TC815

TC815 MICROCHIP | Alldatasheet

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Technical content

Features

• Auto-Range Operation for AC and DC Voltage and Resistance Measurements - Two User Selected AC/DC Current Ranges 20mA and 200mA  22 Operating Ranges - 9 DC/AC Voltage - 4 AC/DC Current - 9 Resistance and Low Power Ohms  Display HOLD Function  3-1/2 Digit Resolution in Auto-Range Mode: - 1/2000  Extended Resolution in Manual Mode: 1/3000  Memory Mode for Relative Measurements: -± 5 % F . S .  Internal AC to DC Conversion Op Amp  Triplex LCD Drive for Decimal Points, Digits and Annunciators  Continuity Detection and Piezoelectric Transducer Driver  Compact Surface Mounted 64-pin Plastic Flat Package  Low Drift Internal Reference: 75ppm/°C  9V Battery Operation: 10mW  Low Battery Detection and LCD Annunciator Device Selection Table General Description The TC815 is a 3-1/2 digit integrating analog-to-digital converter with triplex LCD display drive and automatic ranging. A display hold function is on-chip. Input volt- age/ohm attenuators ranging from 1 to 1/10,000 are automatically selected. Five full scale ranges are pro- vided. The CMOS TC815 contains all the logic and analog switches needed to manufacture an auto- ranging instrument for ohms and voltage measure- ments. User selected 20mA and 200mA current ranges are available. Full scale range and decimal point LCD annunciators are automatically set in auto-range oper- ation. Auto-range operation is available during ohms (high and low power ohms) and voltage (AC and DC) measurements, eliminating expensive range switches in hand-held DMM designs. The auto-range feature may be bypassed allowing decimal point selection and input attenuator selection control through a single line input. Expensive rotary switches are not required. During Manual mode operation, resolution is extended to 3000 counts full scale. The extended range opera- tion is indicated by a flashing 1 MSD. The extended resolution is also available during 200k Ω and 2000V full scale auto-range operation. The Memory mode subtracts a reading, up to ±5% of full scale from subsequent measurements. Typical applications involve probe resistance compensation for resistance measurements, tolerance measurements, and tare weight measurements. The TC815 includes an AC to DC converter for AC measurements. Only external diodes/resistors/ capacitors are required. A complete LCD annunciator set describes the TC815 meter function and measurement range during ohms, voltage and current operation. AC measurements are indicated as well as auto-range operation. A low battery detection circuit also sets the low battery display annunciator. The triplex LCD display drive levels may be set and temperature compensation applied via the V DISP pin. With HOLD low, the display is not updated. A HOLD mode LCD annunciator is activated. The “low ohms” measurement option allows in-circuit resistance measurements by preventing semiconduc- tor junctions from being forward biased. Part Number Package Operating Temperature Range TC815CBU 64-Pin PQFP 0 °Ct o+ 7 0°C 3-1/2 Digit Auto-Ranging A/D Converter with Triplex LCD Drive and Display Hold Function

DS21474B-page 2  2002 Microchip Technology Inc. A continuity buzzer output is activated with inputs less than 1% of full scale. An overrange input signal also enables the buzzer, except during resistance measure- ments, and flashes the MSD display. Featuring single 9V battery operation, 10mW power consumption, a precision internal voltage reference (75ppm/°C max TC) and a compact surface mounted 64-pin quad flat package, the TC815 is ideal for porta- ble instruments. Package Type 52 51 50 4964 63 62 58 57 56 55 54 5360 59 24 25 26 27 28 29 3018 19 20 21 22 23 3217 TC815 CREFL RMREFH ANALOG COM VCC AC/–/AUTO BCP3 VSSD FE2 AGD2 -MEM/BATT BCP2 FE1 AGD1 BCP1 OHM 20mA BUZ FE0 AGD0 BCP0 XTAL1 XTAL2 VDISP BP1 BP2 BP3 LOΩ/A Ω/V k/m/ HOLD NC ΩR1 ΩR4 ΩR2 ΩR3 CI ACVL II CREFH REFHI VI VR4 VR5 VR2 VR3 ΩR5 NC NC RMREFL RX CFI AD1 AD0 RΩBUF RVIBUF ACVH VSSA DGND RANGE -MEM I HOLD CAZ NC DC/AC Ω/LOWΩ 64-Pin PQFP

 2002 Microchip Technology Inc. DS21474B-page 3 TC815 Typical Application and Test Circuit -MEM AUTO HOLD LO kΩ mVA AC – + 1150 7 8 9 10 12 13 25 26 24 23 22 21 20 19 18 16 15 14 R6/100kΩ R7/100kΩ R8/220Ω (PTC) Positive Temperature Coefficient Resistor R5/1.6385MΩ 38R4/163.85kΩ 37R3/16.385kΩ 36R2/1638.5Ω 42 53 52 56 46 54 55 49 47 60 51 32 33 29 34 ADI ACVH ACVL R ΩBUF RVIBUF C AZ INT HOLD CIF C REFL CREFH ANALOG COM REFHI RM REFH -MEM Manual RANGE Change DC/AC or Ω/LOWΩ I OHMS 20mA Digital GND VSSD VSSA VCC XTAL1BUZ XTAL2 VI (÷1) VR2 (÷10) VR3 (÷100) VR4 (÷1,000) VR5 (÷10,000) ADO R1/163.85 R14/9.9MΩ R12/1.11MΩ R11/101kΩ R10/10kΩ R9/1kΩ R13 500kΩ 6.2V 20mA 200mA Current Input Voltage Input Common 0.01 µF Ohms Input 0.1µF If LCD Bias is Connected to DIG GND, Peak Drive Signal ≈ 5V. LCD Bias Tri-Plex LCD Display Segment & Decimal Point Drive 1's10's100's 1000'sDisplay Annunciators Backplane Drivers Ohms Range Attenuator RMREFL ΩR5 (÷ 10,000) ΩR4 (÷ 1,000) ΩR3 (÷ 100) ΩR2 (÷ 10) R1 (÷ 1) II RX VDISP BP1 BP2 BP3 LO Ω/AΩV K/m HOLD AC/–/AUTO -MEM/ BATT BCP3 BCP2FE2 AGD2 BCP1 FE1 AGD1 BCP0 FE0 AGD0 R15 R16 D3 D4 EnableAudio Transducer 32.768kHz ( 33kHz) 9V+ – 39pf V V Ω Ω 20mA 20mA 200mA 200mA SIB SIA To VCC 153.850mV R19/5kΩ R18/24kΩ CREF 0.1µF R20 100 kΩ 0.01µF C INTCAZ150 kΩ 200 kΩ 0.1µF0.1µF RΩBUF RVIBUFR26/3kΩR24/10kΩ R23/10kΩ R22/470kΩ R21/2.2MΩ C4/µf4.7µf C2/0.22µF R27/2kΩ C1/1µF C5/1µf– + – + Voltage Range Attenuator *Not Required when Resistor Network is used. TC815 3-1/2 Digit Auto-Ranging DMM with HOLD Function

DS21474B-page 4  2002 Microchip Technology Inc.

1.0 ELECTRICAL

Absolute Maximum Ratings* Power Dissipation (T A ≤ 70°C) Operating Temperature Range: *Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. TC815 ELECTRICAL SPECIFICATIONS Electrical Characteristics: VA =9 V ,TA = +25°C, unless otherwise specified (see Typical Application and Test Circuit Figure). Symbol Parameter Min Typ Max Unit Test Conditions Zero Input Reading Input Resistor -0000 0000 +0000 Digital Reading 200mV Range w/o 10M Ω Input -0001 — +0001 Digital Reading 200mV Range w/10M Ω Input -0000 0000 +0000 Digital Reading 20mA and 200mA Range RE Rollover Error — — ±1 Count 200mV Range w/o 10M Ω Input Resistor — — ±3 200mV Range w/10M Ω Input — — ±1 20mA and 200mA Range NL Linearity Error — — ±1 Count Best Case Straight Line I IN Input Leakage Current — — 10 pA EN Input Noise — 20 — µVp-p BW = 0.1 to 10Hz AC Frequency Error — ±1 — % 40Hz to 500Hz — ±5 — % 40Hz to 200Hz Open Circuit Voltage — 570 660 mV Excludes 200 Ω Range for OHM Measurements Open Circuit Voltage — 285 350 mV Excludes 200 Ω Range for LO OHM Measurement VCOM Analog Common Voltage 2.5 2.6 3.3 V (V + -V COM) VCTC Common Voltage Temperature Coefficient — — 50 ppm/°C Display Multiplex Rate — 100 — Hz VIL Low Logic Input — — 1 V 20mA ,A C,I ,L O WΩ,H O L D Range, -MEM, OHMs (Relative to DGND Pin 58) Logic 1 Pull-up Current — 25 — µA2 0 m A ,A C,I ,L O WΩ,H O L D Range, -MEM, OHMs (Relative to DGND Pin 58) Buzzer Drive Frequency — 4 — kHz Low Battery Flag Voltage 6.3 6.6 7.0 V V CC to VSSA Operating Supply Current — 0.8 1.5 mA

 2002 Microchip Technology Inc. DS21474B-page 5 TC815

2.0 PIN DESCRIPTIONS

T h ed e s c r i p t i o n so ft h ep i n sa r el i s t e di nT a b l e2 - 1 . TABLE 2-1: PIN FUNCTION TABLE Pin Number (64-Pin Plastic) Quad Flat Package Symbol Description 1 NC Logic Input. “0” (Digital Ground) for resistance measurement. 2O H M Logic Input. “0” (Digital Ground) for 20mA full scale current measurement. 32 0 m A Audio frequency, 4kHz, output for continuity indication during resistance measurement. 4 BUZ Audio frequency, 4kHz, output for continuity indication during resistance measurement. A non-continuous 4kHz signal is output to indicate an input overrange during voltage or current measurements. 5 XTAL1 32.768kHz Crystal Connection. 6 XTAL2 32.768kHz Crystal Connection. DISP Sets peak LCD drive signal: VP -V DD -V DISP.V DISP m a ya l s ob eu s e dt oc o m p e n s a t ef o r temperature variation of LCD crystal threshold voltage. 8 BP1 LCD Backplane #1. 9 BP2 LCD Backplane #2. 10 BP3 LCD Backplane #3.

11 LO Ω/A LCD Annunciator segment drive for low ohms resistance measurement and current

measurement. 12 Ω/V LCD Annunciator segment drive for resistance measurement and voltage measurement. 13 k/m/HOLD LCD Annunciator segment drive for k (“kilo-ohms”), m (“milliamps” and “millivolts”) and HOLD mode.

14 BCP0

(One’s digit) LCD segment drive for “b,” “c” segments and decimal point of least significant digit (LSD). 15 ADG0 LCD segment drive for “a,” “g,” “d” segments of LSD. 16 FE0 LCD segment drive for “f” and “e” segments of LSD. 17 NC No connection. 18 BCP1 LCD segment drive for “b,” “c” segments and decimal point of 2nd LSD. 19 AGD1 LCD segment drive for “a,” “g,” “d” segments of 2nd LSD (Ten’s digit). 20 FE1 LCD segment drive for “f” and “e” segments of 2nd LSD.

21 BCP2 LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD

(Hundred’s digit). 22 AGD2 LCD segment drive for “a,” “g,” “d” segments of 3rd LSD. 23 FE2 LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD.

24 BCP3 LCD segment drive for “b,” “c” segments and decimal point of MSD

(Thousand’s digit). 25 AC/-/AUTO LCD annunciator drive signal for AC measurements, polarity, and auto-range operation. 26 -MEM/BATT LCD annunciator drive signal for low battery indication and Memory (Relative Measurement) mode. 27 V SSD Negative battery supply connection for internal digital circuits. Connect to negative terminal of battery. 28 V CC Positive battery supply connection.

29 ANALOG

Analog circuit ground reference point. Nominally 2.6V below V CC. 30 RM REFH Ratiometric (Resistance measurement) reference high voltage. 31 RM REFL Ratiometric (Resistance measurement) reference low voltage. 32 C REFL Reference capacitor negative terminal C REF 0.1µf. 33 C REFH Reference capacitor positive terminal C REF 0.1µf. 34 REFHI Reference voltage for voltage and current measurement; nominally 163.85mV.

DS21474B-page 6  2002 Microchip Technology Inc. 35 ΩR1 Standard resistor connection for 200 Ω full scale. 36 ΩR2 Standard resistor connection for 2000 Ω full scale. 37 ΩR3 Standard resistor connection for 20k Ω full scale range. 38 ΩR4 Standard resistor connection for 200k Ω full scale range. 39 ΩR5 Standard resistor connection for 2000k Ω full scale range. 40 VR3 Voltage measurement ÷ 100 attenuator. 41 VR2 Voltage measurement ÷ 10 attenuator. 42 VR5 Voltage measurement ÷ 10,000 attenuator. 43 VR4 Voltage measurement ÷ 1000 attenuator. 44 V I Unknown voltage input ÷ 1 attenuator. 45 I I Unknown current input. 46 ACVL Low output of AC to DC converter. 47 C I Integrator capacitor connection. Nominally 0.1µf. (Low dielectric absorption. Polypropylene dielectrics suggested.) 48 NC No connection. 49 C AZ Auto-zero capacitor connection; nominally 0.1µf. 50 R X Unknown resistance input. 51 CFI Input filter connection. 52 AD1 Negative input of internal AC to DC operational amplifier. 53 AD0 Output of internal AC to DC operational amplifier. 54 R ΩBUF Active buffer output for resistance measurement. Integration resistor connection. Integrator resistor nominally 220kΩ. 55 RVIBUF Active buffer output for voltage and current measurement. Integration resistor connection. Integration resistor nominally 150kΩ. 56 ACVH Positive output of AC to DC converter. 57 V SSA Negative supply connection for analog circuits. Connect to negative terminal of 9V battery. 58 DGND Internal logic digital ground. The logic “0” level. Nominally 4.7V below VCC. 59 RANGE Input to set manual operation and change ranges. 60 HOLD Input to hold display. Connect to DIG GND. 61 -MEM Input to enter Memory Measurement mode for relative measurements. The two LSD’s are stored and subtracted from future measurements.

62 DS/AC

Ω/LOWΩ Input that selects AC or DC option during voltage/current measurements. For resistance measurements, Ω/LOWΩ, the ohms or low power (voltage) ohms option can be selected. 63 I Input to select current measurement. Set to logic “0” (Digital ground) for current measurement 64 NC No connection. TABLE 2-1: PIN FUNCTION TABLE (CONTINUED) Pin Number (64-Pin Plastic) Quad Flat Package Symbol Description

 2002 Microchip Technology Inc. DS21474B-page 7 TC815

3.0 DETAILED DESCRIPTION

3.1 Resistance, Voltage, Current

The TC815 is designed to measure voltage, current, and resistance. Auto-ranging is available for resistance and voltage measurements. The OHMS (Pin 2) and I (Pin 63) input controls are normally pulled internally to VCC. By tying these pins to Digital Ground (Pin 58), the TC815 is configured internally to measure resistance, voltage, or current. The required signal combinations are shown in Table 3-1. TABLE 3-1: MEASUREMENT SELECTION LOGIC Note 1: 0=D i g i t a lG r o u n d 2: 1 = Floating or Tied to VCC 3: OHM and I are normally pulled internally high to VCC (Pin 28). This is considered a logic “1.” 4: Logic “0” is the potential at digital ground (Pin 58).

3.2 Resistance Measurements

(Ohms and Low Power Ohms) The TC815 can be configured to reliably measure in- circuit resistances shunted by semiconductor junc- tions. The TC815 Low Power Ohms Measurement mode limits the probe open circuit voltage. This pre- vents semiconductor junctions in the measured system from turning on. In the Resistance Measurement mode, the Ω/LOW Ω (Pin 62) input selects the Low Power Ohms Measure- ment mode. For low power ohms measurements, Ω/LOW Ω (Pin 62) is momentarily brought low to digital ground potential. The TC815 sets up for a low power ohms measurement with a maximum open circuit probe voltage of 0.35V above analog common. In the Low Power Ohms mode, an LCD display annunciator, LOW Ω, will be activated. On power-up, the Low Power Ohms mode is not active. If the Manual mode has been selected, toggling Ω/LOWΩ will reset the TC815 back to the Auto-Range mode. In Manual mode, the decision to make a normal or low power ohms measurement should be made before selecting the desired range. The low power ohms measurement is not available on the 100Ω full scale range. Open circuit voltage on this range is below 2.8V. The standard resistance values are listed in Table 3-2. R8, a positive temperature coefficient resistor, and the 6.2V zener Z1 in Figure 3-1, provide input voltage pro- tection during ohms measurements. TABLE 3-2: OHMS RANGE LADDER NETWORK

3.3 Ratiometric Resistance

The TC815 measures resistance ratiometrically. Accu- racy is set by the external standard resistors connected to Pin 35 through 39. A Low Power Ohms mode may be selected on all but the 200 Ω full scale range. The Low Power Ohms mode limits the voltage applied to the measured system. This allows accurate “in-circuit” measurements when a resistor is shunted by semicon- ductor junctions. Full auto-ranging is provided. External precision standard resistors are automatically switched to provide the proper range. Figure 3-1 shows a detailed block diagram of the TC815 configured for ratiometric resistance measure- ments. During the signal integrate phase, the reference capacitor charges to a voltage inversely proportional to the measured resistance, R X. Figure 3-2 shows the conversion accuracy relies on the accuracy of the external standard resistors only. Normally the required accuracy of the standard resis- tances will be dictated by the accuracy specifications of the users end product. T able 3-3 gives the equivalent ohms per count for various full scale ranges to allow users to judge the required resistor for accuracy. TABLE 3-3: REFERENCE RESISTORS Function Select Pin Selected MeasurementOHM (Pin 2) I (Pin 63) 0 0 Voltage 0 1 Resistance 1 0 Current 1 1 Voltage Full Scale Range Standard Resistance Low Power Ohms Mode 200Ω 163.85 Ω (R1) NO 2000Ω 1638.5 kΩ (R2) YES 20kΩ 16,385Ω (R3) YES 200kΩ 16385Ω (R4) YES 2,000kΩ 1,638,500Ω (R5) YES Full Scale Range Reference Resistor Ω/Count 200k 163.85 0.1 2k 1638.5 1 20k 16385 10 200k 163850 100 2M 1638500 1000

 2002 Microchip Technology Inc. DS21474B-page 9 TC815

3.4 Voltage Measurement

Resistive dividers are automatically changed to provide in range readings for 200mV to 2000V full scale readings (Figure 3-3). The input resistance is set by external resistors R14/R13. The divider leg resistors are R9-R12. The divider leg resistors give a 200mV signal V I (Pin 44) for full scale voltages from 200mV to 2000V. For applications which do not require a 10m Ω input impedance, the divider network impedances may be lowered. This will reduce voltage offset errors induced by switch leakage currents. FIGURE 3-3: TC815 ANALOG SECTION TC815 –2.8V REF AMP 10kΩ VCC 1.5k S43 VCC R18/24k VCC R19/5k ANALOG COM REFHI RMREFH 163.85mV≈ 0.1µFCREFH

51 CIF

0.01µF R20/100kΩ To Digital Section S38 AZ Comparator Integrator 49 47 INT 0.01µF0.01µF CINT RVI BUF 150 k 54 R BUF 220 kRBUF RBUF S34 DE  S20 DE S18 DE S19 DE+ S16 DE+ S17 DE- Buffer S35 S37 INT+ +DC C1/1µF 0.22 µF ACVH S15 AZ 50R7/100kΩ R6/100kΩ R5/1.638MΩ R1/163.85Ω R4/163.85kΩ R3/16385Ω R2/1638.5Ω RMREFL ΩR ΩR ΩR ΩR ΩR 0.01µF Ohms Input Current Input R8/220 0.1µF (PTC) 6.2V 200mA R15/9 20mA R16/1 I 45I R12/1.11M R11/101k R10/10k R9/1k ACVL 46 R24 10k R23 10kΩ R26 33kΩ R27/2kΩ Common 1µF 1µF V 44I VR2 41 VR3 40 VR4 43 VR2 42 ADO ADI Voltage Input R22 470 k R21 2.2 M R14/9.9MΩ R13/500kΩ* 4.7µF S28 S27 S26 S25 S21 DE  S12 V  1/1 1/1k 1/1 +AC INT( +DC) S11 S13 AC-to-DC Converter Op Amp V1/1 V1/10 V1/100 V1/1k V1/10k 1/10 1/100 1/1k 1/10k S32S33 S31 S30 S29 CCV S10 + 1 S6 S7 S8 S9 *Not required when Resistor Network is used. INT AC k 1/10k DE

33 CREFH

32 CREFL

S24 1/10k   CAZ S44 HI S14 S40 INT AC LO S22 S22 S39 1.5k Ω Ω Ω Ω Ω Ω W ΩΩ Ω Ω Ω Ω Ω ΩΩ WΩ Ω Ω ΩΩ Ω Ω Ω Ω ΩΩ Ω Ω Ω Ω Ω Ω ΩΩ Ω Ω Ω Ω Ω Ω Ω W Ω ΩRX

DS21474B-page 10  2002 Microchip Technology Inc.

3.5 Current Measurement

The TC815 measures current only under manual range operation. The two user selectable full scale ranges are: 20mA and 200mA. Select the current Measure- ment mode by holding the I input (Pin 63) low at digital ground potential. The OHM input (Pin 2) is left floating or tied to the positive supply. Two ranges are possible. The 20mA full scale range is selected by connecting the 20mA input (Pin 3) to digital ground. If left floating the 200mA full scale range is selected. External current to voltage conversion resistors are used at the I I input (Pin 45). For 20mA measurements a1 0Ω resistor is used. The 200mA range needs a 1 Ω resistor; full scale is 200mV. PC board trace resistance between analog common and R16 (see Figure 2-1) must be minimized. In the 200mA range, for example, a 0.05 trace resistance will cause a 5% current to voltage conversion error at I I (Pin 45). The extended resolution measurement option operates during current measurements. T o minimize rollover error the potential difference between ANALOG COM (Pin 29) and system common must be minimized.

3.6 Measurement Options

(AC to DC Measurements) In voltage and current measurements, the TC815 can be configured for AC measurements. An on-chip oper- ational amplifier and external rectifier components per- form the AC to DC conversion. When power is first applied, the TC815 enters the DC Measurement mode. For AC measurements (current or voltage), AC /DC (Pin 62) is momentarily brought low to digital ground potential; the TC815 sets-up for AC mea- surements and the AC liquid crystal display annuncia- tor activates. Toggling AC /DC low again will return the TC815 to DC operation. If the Manual Operating mode has been selected, tog- gling AC /DC will reset the TC815 back to the Auto- Range mode. In Manual mode operation, AC or DC operation should be selected first and then the desired range selected. The minimum AC voltage full scale voltage range is 2V. The DC full scale minimum voltage is 200mV. AC cur- rent measurements are available on the 20mA and 100mA full scale current ranges.

 2002 Microchip Technology Inc. DS21474B-page 11 TC815

4.0 CONVERSION TIMING

The TC815 analog-to-digital converter uses the con- ventional dual slope integrating conversion technique with an added phase that automatically eliminates zero offset errors. The TC815 gives a zero reading with a zero volt input. The TC815 is designed to operate with a 32.768kHz crystal. The 32kHz crystal is low cost and readily avail- able; it serves as a time-base oscillator crystal in many digital clocks. (See External Crystal Sources.) The external clock is divided by two. The internal clock frequency is 16.348kHz, giving a clock period of 61.04µsec. The total conversion — auto-zero phase, signal integrate and reference deintegrate — requires 8000 clock periods or 488.3msec. There are approxi- mately two complete conversions per second. The integration time is fixed at 1638.5 clock periods or 100msec. This gives rejection of 50/60Hz AC line noise. The maximum reference de-integrate time, represent- ing a full scale analog input, is 3000 clock periods or 183.1msec during manual extended resolution opera- tion. The 3000 counts are available in Manual mode, extended resolution operation only. In Auto-Ranging mode, the maximum de-integrate time is 2000 clock periods. The 1000 clock periods are added to the auto- zero phase. An auto-ranging, or manual conversion takes 8000 clock periods. After a zero crossing is detected in the Reference De-integrate mode, the auto- zero phase is entered. Figure 4-1 shows the basic TC815 timing relationships. FIGURE 4-1: BASIC TC815 CONVERSION TIMING External Crystal = 32.768kHz Internal Clock Period = TP = 2/32.768 = 61.04µsec Total Conversion Time = TCONV =8 0 0 0( TP) =4 8 8 . 3 m e c≈ 2C o n v / S e c . Integration Time = TI = 1638.5 (TP) = 100.0msec. Maximum Reference De-integration Time = TDE =3 0 0 0( TP) = 183.1msec (Manual Extended Resolution) Minimum Auto-Zero Time = (8000-3000-1638.5) (T P)=2 0 5 . 1 m s e c (Manual, Extended Resolution) = (8000-2000-1638.5) (T P)=2 6 6 . 2 m s e c (Auto-Range) Auto-Zero Phase Min. Auto-Zero Time 3361.5TP TI TDE To Input Signal TCONV 8000 TP Fixed 1638.5 TP *Max 3000.0 TP Extended Resolution Zero Crossing *In Auto-Range Operation Maximum is 2000TP and Minimum Auto-Zero time i s 4361.5TP Signal Integrate Phase Reference De-integrate Phase Next Conversion Auto-Zero Cycle TC815

DS21474B-page 12  2002 Microchip Technology Inc.

5.0 MANUAL RANGE SELECTION

The TC815 voltage and resistance auto-ranging fea- ture can be disabled by momentarily bringing RANGE (Pin 59) to digital ground potential (Pin 58). When the change from auto-to-manual ranging occurs, the first manual range selected is the last range in the Auto- Ranging mode. The TC815 power-up circuit selects auto-range opera- tion initially. Once the manual range option is entered, range changes are made by momentarily grounding the RANGE control input. The TC815 remains in the Manual Range mode until the measurement function (voltage or resistance), or measurement option (AC / DC, Ω/LOΩ) changes. This causes the TC815 to return to auto-ranging operation. The “Auto” LCD annunciator driver is active only in the Auto-Range mode. Table 5-1 shows typical operation, where the manual range selection option is used. Also shown is the extended resolution display format. Also see Figure 5-1 through Figure 5-3. Note 1: A flashing MSD is shown as a “1”. A flashing MSD indicates the TC815 is over-ranging if all other digits are zero. 2: The first manual range selected is the last range in the Auto-Ranging mode. 3: A flashing MSD with a non-zero display indicates the TC815 has entered the Extended Resolution Operating mode. An additional 1000 counts of resolution is available. This extended operation is available only in manual operation for voltage, resistance and current measurements. 4: = Momentary ground connection. TABLE 5-1: MANUAL RANGE OPERATION Input DC Volts AC Volts Ohm LO Ohm 23.5V 18.2V 18.2kΩ 2.35MΩ Range Display Range Range Display Range Range Display Power-on Auto-Range Operation 200mV “1”00.0V 2V “1”000V 200 Ω “1”00.0Ω 2kΩ “1”.000kΩ 20V “1”0.00V — — 20k Ω 18.20Ω 200kΩ “1”.00.0kΩ 200V 23.5V — — — — 2000k Ω “1”350kΩ Manual Operation Input DC Volts AC Volts Ohm LO Ohm 23.5V 18.2V 18.2kΩ 2.35MΩ # of Range Changes (See Note 4) Range Display Range Range Display Range Range Display 1 200V 23.5V 20V 18.20V 20k Ω 18.20V 2000k Ω “1”350kΩ 2 200mV “1”00.0V 2V “1”.000V 200 Ω “1”00.0ΩkΩ 2kΩ “1”.000kΩ 3 2V 1.000V 20V 18.20V 2k Ω “1”000kΩ 20kΩ “1”0.00kΩ 4 20V “1”3.50V 20V 18.2V 20k Ω 18.20kΩ 200kΩ “1”00.0kΩ 5 200V 23.5V 600V 19V 200k Ω 18.2kΩ 2000kΩ “1”350kΩ 6 1000V 24V 2V “1”.000V 2000k Ω 19kΩ 2kΩ “1”.000kΩ 7 200mV “1”00.0mV 20V 18.20V 200k Ω “1”00.0Ω 20kΩ “1”0.00kΩ 8 2V “1”.000V 200V 18.2V 2k Ω “1”.000kΩ 200kΩ “1”00.0kΩ

 2002 Microchip Technology Inc. DS21474B-page 13 TC815 FIGURE 5-1: MANUAL RANGE SELECTION: RESISTANCE MEASUREMENTS For resistance measurements, the buzzer signal does not indicate an overrange condition. The buzzer is used to indicate continuity. Continuity is defined as a resis- tance reading less than 19 counts. FIGURE 5-2: MANUAL RANGE SELECTION: CURRENT MEASUREMENTS FIGURE 5-3: MANUAL RANGE SELECTION: VOLTAGE MEASUREMENTS

5.1 Extended Resolution

The TC815 extends resolution by 50% when operated in the Manual Range Select mode for current, voltage, and resistance measurements. Resolution increases to 3000 counts from 2000 counts. The extended resolu- tion feature operates only on the 2000k Ω and 2000V ranges during auto-range operation. In the Extended Resolution Operating mode, readings above 1999 are displayed with a blinking “1” most sig- nificant digit. The blinking “1” should be interpreted as the digit 2. The three least significant digits display data normally. An input overrange condition causes the most signifi- cant digit to blink and sets the three least significant digits to display “000.” The buzzer output is enabled for input voltage and current signals with readings greater than 2000 counts in both manual and auto-range operation. Manual Range Select Is RX < 19 Output 4kHz Audio Frequency Is RX > 3000 Is RX > 2000 Display "1" 000 Display Last

3 Digits and Flash

*Mode also operates when Auto-Ranging Operation is selected and 2MΩ < R X < 2.999MΩ "1" = > Flashing MSD No Yes Yes No No Yes* Over Range Indicator Continuity Indicator Continuous 4kHz Buzzer Display True Reading TC815 Range Select Output 4kHz Audio Frequency IsIX > 3000 IsIX > 2000 Display "1" 000 Display Last "1" = > Flashing MSD Yes Yes No No Yes Over Range Indicato r Display True Reading TC815 Range Select Output Noncontinuous 4kHz Audio Frequency Is VX > 3000 Is VX > 2000 Display "1" 000 Display Last 3 Digits and Flash MSD Extended Resolution Feature "1" = > Flashing MSD Yes No No Yes Over Range Indicator Display True Reading TC815

DS21474B-page 14  2002 Microchip Technology Inc. 6.0 -MEM OPERATING MODE Bringing -MEM (Pin 61) momentarily low configures the TC815 “-MEM” Operating mode. The -MEM LCD Annunciator becomes active. In this Operating mode, subsequent measurements are made relative to the last two digits (-99) displayed at the time MEM is low. This represents 5% of full scale. The last two significant digits are stored and subtracted from all the following input conversions. The following examples clarify operation: EXAMPLE 6-1: IN AUTO-RANGING EXAMPLE 6-2: IN FIXED RANGE (200.0Ω FULL SCALE) EXAMPLE 6-3: IN FIXED RANGE On power-up, the TC815 “-MEM” mode is not active. Once the “-MEM” is entered, bringing MEM low again, it returns the TC815 to normal operation. The “-MEM” mode is also cancelled whenever the mea- surement type (resistance, voltage, current AC /DC, Ω/LOΩ) or range is changed. The LCD -MEM annunci- ator will be off in normal operation. In the auto-range operation, if the following input signal cannot be converted on the same range as the stored value, the “-MEM” mode is cancelled. The LCD annun- ciator is turned off. The “-MEM” Operating mode can be very useful in resistance measurements when lead length resistance would cause measurement errors.

7.0 AUTOMATIC RANGE

When power is first applied, the TC815 enters the auto- range operating state. The Auto-Range mode may be entered from Manual mode by changing the measure- ment function (resistance or voltage), or by changing the measurement option (AD /DC, Ω/LOΩ). The automatic voltage range selection begins on the most sensitive scale first: 200mV for DC or 2.000V for AC measurements. The voltage range selection flow chart is given in Figure 7-1. Internal input protection diodes to V DD (Pin 28) and VSSA (Pin 57) clamp the input voltage. The external 10MΩ input resistance (see Figure 7-1, R14 and R13) limits current safely in an overrange condition. The voltage range selection is designed to maximize resolution. For input signals less than 9% of full scale (count reading <180), the next most sensitive range is selected. An over range voltage input condition is flagged when- ever the internal count exceeds 2000, by activating the buzzer output (Pin 4). This 4kHz signal can directly drive a piezo electric acoustic transducer. An out of range input signal causes the 4kHz signal to be on 122msec, off for 122 msec, on for 122msec and off for 610msec (see Figure 11-1). During voltage auto-range operation, the extended res- olution feature operates on the 2000V range only. (See Extended Resolution Operating mode discussion.) The resistance automatic range selection procedure is shown in Figure 7-2. The 200 Ω range is the first range selected unless the TC815 low ohms resistance mea- surement option is selected. In low ohms operation, the first full scale range tried is 2k Ω. The resistance range selected maximizes sensitivity. If the conversion results in a reading less than 180, the next most sensitive full scale range is tried. If the conversion is less than 19 in auto-range opera- tion, a continuous 4kHz signal is output at BUZ (Pin 4). An over range input does not activate the buzzer. Out of range input conditions are displayed by a blink- ing most significant digit with the three least significant digits set to “000.” The extended resolution feature operates only on the 2000kΩ and 2000V full scale range during auto-range operation. A blinking “1” most significant digit is inter- preted as the digit 2. The three least significant digits display data normally. R I (N) = 18.21kΩ (20kΩ Range) = > Display 18.21kΩ MEM = > Store 0.21kΩ RI (N+1) = 19.87kΩ (20kΩ Range) = > Display 19.87 - 0.21 = 19.66k Ω RI (N+2) = 22.65kΩ (200kΩ Range) = > Display 22.7kΩ and MEM disappears RI (N) = 18.21kΩ = > Display 18.2kΩ MEM =>S t o r e8 . 2Ω RI (N+1) = 36.7Ω = > Display 36.7 - 8.2 = 28.5 Ω RI (N+2) = 5.8Ω = > Display 5.8 = 2.4Ω* *Will display minus resistance if following input is less than offset stored at fixed range. VI (N) = 0.51V = > Display 0.51V MEM =>S t o r e0 . 5 1 V VI (N+1) = 3.68V = > Display 3.68 - 0.51 = 3.17V VI (N+2) = 0.23V = > Display 0.23 - 0.51 = -0.28V VI (N+3) = -5.21V

 2002 Microchip Technology Inc. DS21474B-page 15 TC815 FIGURE 7-1: AUTO-RANGE OPERATION: VOLTAGE MEASUREMENT TC815N = 0 if DC N = 1 if AC N = 0: 200.0mV Full Scale Range N = 1: 2,000V Full Scale Range Start: Power-on, Function or Measurement Option Change N = 0 if DC N = 1 if AC Kth Conversion VX - (1/10N) VIN VX < 180 VX > 2000 VX > 3000 N = 4 Display "1" 000 Flash MSD N = N + 1 Display Voltae (VX) Display "1" XXX Flash MSD K = K + 1 N = N – 1 Yes Yes Yes Yes No No Yes No No Activate Buzzer Over Range N = NK Remaining in Range Selected during the Kth Conversion

DS21474B-page 16  2002 Microchip Technology Inc. FIGURE 7-2: AUTO-RANGE OPERATION: RESISTANCE MEASUREMENT TC815N = 0 if Ω N = 1 if LOΩ N = 0: 200.0Ω Full Scale Range N = 1: 2,000kΩ Full Scale Range Start: Power-on, Function or Measurement Option Change N = 0 if Ω N =1 if LOWΩ Kth Conversion Continuity Indicator Continuous 4kHz Signal RX = (1/10N) RIN RX < 180 RX < 19 RX >2000 RX >3000 N = 4 N = N + 1 Display Resistance Display "1" XXX Flash MSD Over Range Extended Resolution K = K + 1 N = N – 1Activate Buzzer Yes No Yes Yes Yes No No Yes Yes No No Display "1" 000 Flash MSD Remaining in Range Selected during the Kth Conversion

 2002 Microchip Technology Inc. DS21474B-page 17 TC815

8.0 LOW BATTERY DETECTION

The TC815 contains a low battery detector. When the 9V battery supply has been depleted to a 7V nominal value, the LCD display low battery annunciator is activated. The low battery detector is shown in Figure 8-1. The low battery annunciator remains OFF with the battery supply greater than 0.7V. The annunciator is ON before the supply battery has reached 6.3V. FIGURE 8-1: LOW BATTERY DETECTOR

9.0 TRIPLEX LIQUID CRYSTAL

The TC815 directly drives a triplexed liquid crystal dis- play (LCD) using 1/3 bias drive (see Figure 9-1). All data, decimal point, polarity and function annunciator drive signals are developed by the TC815. A direct connection to a triplex LCD display is possible without external drive electronics. Standard and custom LCD displays are readily available from LCD manufacturers. The LCDs must be driven with an AC signal having zero DC component for long display life. The liquid crystal polarization is a function of the RMS voltage appearing across the backplane and segment driver. The peak drive signal applied to the LCD is: V CC - VDISP. If VDISP, for example, is set at a potential 3V below VCC, the peak drive signal is: VP =V CC – VDISP =3 V An “OFF” LCD segment has an RMS voltage of Vp/3 across it or 1 volt. An “ON” segment has a 0.63Vp sig- nal across it or 1.92V for V CC –VDISP =3 V . Since the V DISP pin is available, the user may adjust the “ON” and “OFF” LCD levels for various manufac- turer’s displays by changing Vp. The liquid crystal threshold voltage moves down with temperature. “OFF” segments may become visible at high LCD oper- ating temperatures. A voltage with a -5 to -20mV/°C temperature coefficient can be applied to V DISP to accommodate the liquid crystal temperature operating characteristics, if necessary. The TC815 internally generates two intermediate LCD drive potentials (V H and V L) from a resistive divider (Figure 9-1), between V CC (Pin 28) and V DISP (Pin 7). The ladder impedance is approximately 150k Ω.T h i s drive method is commonly known as 1/3 bias. With V DISP connected to digital ground VP ≈ 5.0V. The intermediate levels are needed so that drive sig- nals giving RMS “ON” and “OFF” levels can be gener- ated. Figure 9-2 shows a typical drive signal and the resulting wave forms for “ON” and “OFF.” RMS voltage levels across a selected LCD element. Also, see Figure 9-3 and Table 9-1. FIGURE 9-1: 1/3 BIAS LCD DRIVE

9.1 LCD Displays

Although most users will design their own custom LCD display, several manufacturers offer standard displays for the TC815. Figure 9-3 shows a typical display avail- able from Varitronix. 1. Varitronix Ltd. 4/F Liven House, 61-63, King Yip Street Kwun Tong, Hong Kong Tel: (852)2389-4317 Part No.: VIM 310-1 Pin Connector VIM 310-2 Elastomer Connector USA OFFICE: VL Electronics/Varitronix 3250 Wilshire Blvd. Suite 1901 Los Angeles, CA 90010 Tel: (213) 738-8700 2. Adamant Kogyo Co., LTD 16-7, Shinden, 1-Chome, Adachi-Ku, Tokyo, 123, Japan Tel: Tokyo 919-1171 TC815 Comparator+ VCC VSSA Low Battery Detector To LCD Annunciator Selection Logic R VT VT ≈ 7 X = 6.2V VZ 6.2V R1 + R2 TC815 VSSA To Triplex Segment Drive Logic Set VDISP For Proper VP with Resistive Divider VH VL 50k 50k 50k VDISP6 VCC VP = VCC – VDISP "OFF" = VP/3 RMS "ON" = VP RMS11

 2002 Microchip Technology Inc. DS21474B-page 19 TC815 TABLE 9-1:

10.0 EXTERNAL CRYSTAL

The TC815 is designed to operate with a 32,768Hz crystal. This frequency is internally divided by two to give a 61.04µsec clock period. One conversion takes 8000 clock periods or 488.3 msec ( ≈ 2 conversions/ second). Integration time is 1638.5 clock periods or 100msec. The 32kHz quartz crystal is readily available and inex- pensive. The 32kHz crystal is commonly used in digital clocks and counters. Several crystal sources exist. A partial listing is:  Statek Corporation 512 N. Main Orange, CA 92668 (714) 639-7810 TWX: 910-593-1355 TELEX: 67-8394  Fox Electronics

5570 Enterprise Parkway

Fort Myers, FL 33905 (941) 693-0099 Contact manufacturer for full specifications. PAD BP1 BP2 BP3 PAD COM1 COM2 COM3 1B P 1 / /1 9/ // 2 / BP2 / 20 / / / 3 / / BP3 21 / / / 4/ L O Ω A2 2 / / / 5/W V 2 3 / / / 6H O L D k m2 4 / / / 7b 1c 1/ 2 5 // / 8a 1g 1 d 1 2 6 // / 9f 1e 1 / 2 7 / / / 10 b2 c2 P2 28 / / / 11 a2 g2 d2 29 / / / 12 f2 e2 / 30 / / / 13 b3 c3 P3 31 / / / 14 a3 g3 d3 32 / / / 15 f3 e3 / 33 / / / 16 b4 c4 P4 34 / / /

17 AC Auto 35 / / /

18 –MEM / 36 / / /

DS21474B-page 20  2002 Microchip Technology Inc. 11.0 “BUZZER” DRIVE SIGNAL The TC815 BUZ output (Pin 4) will drive a piezo electric audio transducer. The signal is activated to indicate an input overrange condition for current and voltage measurements, or continuity during resistance measurements. During a resistance measurement, a reading less than 19 on any full scale range, causes a continuous 4kHz signal to be output. This is used as a continuity indication. A voltage or current input measurement overrange is indicated by a noncontinuous 4kHz signal at the BUZ output. The LCD display MSD also flashes and the three least significant digits are set to display zero. The buzzer drive signal for over range is shown in Figure 11-1 The buzzer output is active for any reading over 2000 counts in both manual and auto-range oper- ation. The buzzer is activated during an extended res- olution measurement. The BUZ signal swings from V CC (Pin 28) to Digital Ground (Pin 58). The signal is at VCC when not active. The BUZ output is also activated for 15msec whenever a range change is made in auto-range or manual oper- ation. Changing the type of measurement (voltage, cur- rent, or resistance) or measurement option (AC /DC, Ω/LOΩ) will also activate the buzzer output for 15msec. A range change during a current measurement will not activate the buzzer output. FIGURE 11-1: TC815 WAVEFORM FOR BUZZER OUTPUT 122ms 122ms 122ms 122ms 122ms610ms Digital Ground 4kHz Signal1 Conversion Noncontinuous Buzzer Signal Indicates Input OverrangePower-up 4000 8000 12000 Change Range Change Range Change Range Change Input VIN = 3.2V VIN = 250mV

1000 Clock Pulses

1638.5CP Integrate De-integrate Auto-Zero BUZ (Pin 4) 200mV Range Over Range 2,000V Range In Range 2,000V Range In Range 2,000V Range In Range 2,000V Range Out of Range 200mV Range Extended Range Manual RangeAuto-Ranging 3000CP250CP2500CP250CP250CP 122ms 2000CP Internal TC815 Signals 4kHz 4kHz 4kHz Due to Range Change Due to Manual Range Change 4kHz15ms15ms15ms 610ms 122ms 122ms122ms Buzzer activated due to Previous Conversion Over Range One Cycle of Over Range Buzzer Buzzer activated due to Power-up Buzzer activated due to Previous Over Range Due to Range Change

 2002 Microchip Technology Inc. DS21474B-page 21 TC815 Vendors for piezo electric audio transducers are:  Gulton Industries Piezo Products Division

212 Durham Avenue

Metuchen, New Jersey 08840 (201) 548-2800 Typical P/Ns: 102-95NS, 101-FB-00 T aiyo Yuden (USA) Inc. Arlington Center

714 West Algonquin Road

Arlington Heights, Illinois 60005 Typical P/Ns: CB27BB, CB20BB, CB355BB

11.1 Display Decimal Point Selection

The TC815 provides a decimal point LCD drive signal. The decimal point position is a function of the selected full scale range, as shown in Table 11-1.

11.2 AC-to-DC Converter Operational

The TC815 contains an on-chip operational amplifier that may be connected as a rectifier for AC-to-DC volt- age and current measurements. Typical operational amplifier characteristics are: S l e w R a t e :1 V / µ s e c  Unity-Gain Bandwidth: 0.4MHz  Open Loop Gain: 44dB  Output Voltage Swing (Load = 10k Ω) ± 1.5V (Referenced to Analog Common) When the AC measurement option is selected, the input buffer receives an input signal through switch S14, rather than switch S11. With external circuits, the AC Operating mode can be used to perform other types of functions within the constraints of the internal opera- tional amplifier. External circuits that perform true RMS conversion, or a peak hold function are typical examples.

11.3 Component Selection

11.3.1 INTEGRATION RESISTOR

The TC815 automatically selects one of two external integration resistors. RVBUF (pin 55) is selected for voltage and current measurement. R ΩBUF (Pin 54) is selected for resistance measurements.

11.3.2 RVIBUF SELECTION (PIN 55)

In auto-range operation, the TC815 operates with a 200mV maximum full scale potential at V I (Pin 44). Resistive dividers at VR2 (Pin 41), VR3 (Pin 40), VR4 (Pin 43), and VR5 (Pin 42) are automatically switched to maintain the 200V full scale potential. In Manual mode, the Extended Operating mode is acti- vated, giving a 300mV full scale potential at V I (Pin 44). The integrator output swing should be maximized, but saturations must be avoided. The integrator will swing within 0.45V of V CC (Pin 28) and 0.5V of V SS (Pin 57) without saturating. A ±2V swing is suggested. The value of RVIBUF is easily calculated, assuming a worst case extended resolution input signal: V INT = Integrator swing = ±2V tI = Integration time = 100msec CI = Integration capacitor = 0.1µF VMAX = Maximum input at V I = 300mV EQUATION 11-1:

11.3.3 R ΩBUF SELECTION (PIN 54)

In ratiometric resistance measurements, the signal at RX (pin 50) is always positive, with respect to analog common. The integrator swings negative. The worst case integrator swing is for the 200 Ω range with the manual, extended resolution option. The input voltage, VX (Pin 50) is easily calculated (see Figure 11-2): VANCOM = Potential at Analog Common ≈ 2.7V R8 = 220 Ω RI = 163.85 Ω RX = 300 Ω RS = Internal switch 33 resistance ≈ 600Ω EQUATION 11-2: TABLE 11-1: DECIMAL POINT SELECTION 1*9 * 9 * 9 Full Scale Range DP3 DP2 DP1 2000V, 2000kΩ OFF OFF OFF 200V, 200.0kΩ OFF OFF ON 20V, 20.00kΩ OFF ON OFF 2V, 2.000kΩ ON OFF OFF 200V, 200.0Ω OFF OFF OFF 200mV, 200.0Ω OFF OFF ON 20mA OFF ON OFF 200mA OFF OFF ON RVIBUF = VMAX(TI) VINT(CI) = 150kΩ RΩBUF = VCC -( VANCOM)RX (RX +R S +R 1 +R 8) =0 . 6 3 V

DS21474B-page 22  2002 Microchip Technology Inc. For a 3.1V integrator swing, the value of R ΩBUF is easily calculated: VINT = Integrator swing = 3.1V tI = Integration time = 100msec CI = Integration capacitor = 0.1µF RXMAX =3 0 0Ω VX MAX = 700mV EQUATION 11-3: FIGURE 11-2: R Ω CALCULATION (200 Ω MANUAL OPERATION) With a low battery voltage of 6.6V, analog common will be approximately 3.6V above the negative supply ter- minal. With the integrator swinging down from analog common toward the negative supply, a 3.1V swing will set the integrator output to 0.5V above the negative supply.

11.4 Capacitors - C INT,C AZ and CREF

The integration capacitor, C INT, must have low dielec- tric absorption. A 0.1µF polypropylene capacitor is sug- gested. The auto-zero capacitor, C AZ, and reference capacitor, C REF, should be selected for low leakage and dielectric absorption. Polystyrene capacitors are good choices.

11.5 Reference Voltage Adjustment

The TC815 contains a low temperature drift internal voltage reference. The analog common potential (Pin 29) is established by this reference. Maximum drift is a low 75ppm/°C. Analog common is designed to be approximately 2.6V below V CC (Pin 28). A resistive divider (R18/R19, Functional Diagram) sets the TC815 reference input voltage (REFHI, Pin 34) to approxi- mately 163.85mV. With an input voltage near full scale on the 200mV range, R19 is adjusted for the proper reading.

11.6 Display Hold Feature

The LCD will not be updated when HOLD (Pin 60) is connected to GND (Pin 58). Conversions are made, but the display is not updated. A HOLD mode LCD annun- ciator is activated when HOLD is low. The LCD HOLD annunciator is activated through the triplex LCD driver signal at Pin 13.

11.7 Flat Package Socket

Sockets suitable for prototype work are available. A USA source is:  Nepenthe Distribution

2471 East Bayshore, Suite 520

Palo Alto, CA 94303 (415) 856-9332 TWX: 910-373-2060 “CBQ” Socket, Part No. IC51-064-042

11.8 Resistive Ladder Networks

Resistor attenuator networks for voltage and resistance measurements are available from:  Caddock Electronics

1717 Chicago Avenue

Riverside, CA 92507 Tel: (714) 788-1700 TWX: 910-332-6108 TABLE 11-2: RESISTIVE LADDER NETWORKS RΩBUF = VXMAX(TI) CI(VINT) = 200kΩ 163.85Ω 220Ω 300Ω RS ≈ 600ΩSW33 VX Analog Common = VCC – 3V VCC = 9V Attenuator Accuracy Attenuator Type Caddock Part Number 0.1% Voltage 1776-C441 0.25% Voltage 1776-C44 0.25% Resistance T1794-204-1

 2002 Microchip Technology Inc. DS21474B-page 23 TC815

12.0 PACKAGING INFORMATION

12.1 Package Marking Information

Package marking data not available at this time.

12.2 Taping Form

12.3 Package Dimensions

Component Taping Orientation for 64-Pin PQFP Devices W User Direction of Feed PIN 1 Standard Reel Component Orientation for TR Suffix Device P Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 64-Pin PQFP 32 mm 24 mm 250 13 in Carrier Tape, Number of Components Per Reel and Reel Size Note: Drawing does not represent total number of pins. .018 (0.45) .012 (0.30) .031 (0.80) TYP. .555 (14.10) .547 (13.90) .555 (14.10) .547 (13.90) .687 (17.45) .667 (16.95) .687 (17.45) .667 (16.95) .010 (0.25) TYP. .130 (3.30) MAX. .120 (3.05) .100 (2.55) .041 (1.03) .031 (0.78) 7° MAX. .009 (0.23) .005 (0.13)PIN 1 64-Pin PQFP Dimensions: mm (inches)

DS21474B-page 24  2002 Microchip Technology Inc. SALES AND SUPPORT Data Sheets Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom- mended workarounds. T o determine if an errata sheet exists for a particular device, please contact one of the following: 1. Your local Microchip sales office 2. The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277 3. The Microchip Worldwide Site (www.microchip.com) Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using. New Customer Notification System Register on our web site (www.microchip.com/cn) to receive the most current information on our products.

 2002 Microchip Technology Inc. DS21474B-page 25 TC815 Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. No representation or warranty is given and no liability is assumed by Microchip T echnology Incorporated with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Use of Microchip’s products as critical com- ponents in life support systems is not authorized except with express written approval by Microchip. No licenses are con- veyed, implicitly or otherwise, under any intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, FilterLab, K EELOQ,m i c r o I D ,M P L A B ,P I C ,P I C m i c r o ,P I C M A S T E R , PICSTART, PRO MATE, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Tech- nology Incorporated in the U.S.A. and other countries. dsPIC, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, MXDEV, PICC, PICDEM, PICDEM.net, rfPIC, Select Mode and Total Endurance are trademarks of Microchip Technology Incorporated in the U.S.A. Serialized Quick Turn Programming (SQTP) is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2002, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received QS-9000 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona in July 1999 and Mountain View, California in March 2002. The Company’s quality system processes and procedures are QS-9000 compliant for its PICmicro ® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, non-volatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001 certified.

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