TC826 MICROCHIP | Alldatasheet
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Technical content
Features
- Bipolar A/D Conversion 2.5% Resolution Direct LCD Display Drive ‘Thermometer’ BAR or DOT Display 40 Data Segments Plus Zero Over Range Plus Polarity Indication Precision On-Chip Reference: 35ppm/°C Differential Analog Input Low Input Leakage: 10pA Display Flashes on Over Range Display HOLD Mode Auto-Zero Cycle Eliminates Zero Adjust Potentiometer 9V Battery Operation Low Power Consumption: 1.1mW 20mV to 2.0V Full Scale Operation Non-Multiplexed LCD Drive for Maximum Viewing Angle Device Selection Table General Description In many applications, a graphical display is preferred over a digital display. Knowing a process or system operates, for example, within design limits is more valu- able than a direct system variable read out. A bar or moving dot display supplies information precisely with- out requiring further interpretation by the viewer. The TC826 is a complete analog-to-digital converter with direct liquid crystal (LCD) display drive. The 40 LCD data segments plus zero driver give a 2.5% reso- lution bar display. Full scale differential input voltage range extends from 20mV to 2V. The TC826 sensitivity is 500µV. A low drift 35ppm/°C internal reference, LCD backplane oscillator and driver, input polarity LCD driver, and over range LCD driver make designs simple and low cost. The CMOS design required only 125µA from a 9V battery. In +5V systems, a TC7660 DC to DC converter can supply the -5V supply. The differential analog input leakage is a low 10pA. Two display formats are possible. The BAR mode dis- play is like a ‘thermometer’ scale. The LCD segment driver that equals the input, plus all below it are on. The DOT mode activates only the segment equal to the input. In either mode, the polarity signal is active for negative input signals. An over range input signal causes the display to flash and activates the over range annunciator. A HOLD mode can be selected that freezes the display and prevents updating. The dual slope integrating conversion method with auto-zero phase maximizes noise immunity and elimi- nates zero scale adjustment potentiometers. Zero scale drift is a low 5 µV/°C. Conversion rate is typically 5 per second and is adjustable by a single external resistor. A compact, 0.5" square, flat package minimizes PC board area. The high pin count LSI package makes multiplexed LCD displays unnecessary. Low cost, direct drive LCD displays offer the widest viewing angle and are readily available. A standard display is avail- able now for TC826 prototyping work. Part Number Package Temperature Range TC826CBU 64-Pin PQFP 0 °Ct o+ 7 0°C Analog-to-Digital Converter with Bar Graph Display Output
DS21477B-page 2 2002 Microchip Technology Inc. Package Type Typical Application 302928 5051 BAR 35 BAR 36 BAR 37 BAR 38 BAR 39 BAR 40 OR POL- BAR/DOT HOLD TEST 626364 49 BAR 15 NC BAR 34 4 45 BAR 30 BAR 14 BAR 13 BAR 12 BAR 11 BAR 10 BAR 9 BAR 8 BAR 7 BAR 6 BAR 5 BAR 4 BAR 3 BAR 2 BAR 1 BAR 29 BAR 28 BAR 27 BAR 26 BAR 25 BAR 24 BAR 23 BAR 22 BAR 21 BAR 20 BAR 19 BAR 18 NC OSC1 BP ANALOG COMMON +IN -IN REF IN V DD VSS OSC2 BAR 0 CREF+ CREF- VBUF CAZ VINT NC NC BAR 17 BAR 16 BAR 32 BAR 33 BAR 31 TC826CBU 64-Pin PQFP 58 2 43 60 Segment Drive TC826 CINT CAZRINT R2R1 -IN +IN CREF 1.0mf ROSC 430kΩ Backplane
41 Segment LCD
V SS VDD REF IN ANALOG COMMON -IN +IN BAR 0- BAR 40 POL- –O R 1MΩ 1MΩ 1MΩ Component 2V Full Scale 200mV Full Scale 20mV Full Scale RINT CINT CREF 2MΩ 20kΩ 20kΩ 0.033mf 0.033mf 0.033mf 1mf 1mf 1mf CAZ 0.068mf 0.068mf 0.014mf R 1 + R2 = 250kΩ
2002 Microchip Technology Inc. DS21477B-page 3 TC826
1.0 ELECTRICAL
Absolute Maximum Ratings* Analog Input Voltage (Either Input) (Note 1)... V+ to V- Power Dissipation (TA ≤ 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. TC826 ELECTRICAL SPECIFICATIONS Note 1: Input voltages may exceed the supply voltages when the input current is limited to 100 µA. 2: Static sensitive device. Unused devices should be stored in conductive material to protect devices from static discharge and static fields. 3: Backplane drive is in phase with segment drive for ‘off’ segment and 180°C out of phase for ‘on’ segment. Frequency is 10 times conversion rate. 4: Logic input pins 58, 59, and 60 should be connected through 1M Ω series resistors to VSS for logic 0. Electrical Characteristics: VS =9 V ;ROSC =4 3 0 kΩ;T A = 25°C; Full Scale = 20mV, unless otherwise stated. Symbol Parameter Min Typ Max Unit Test Conditions Zero Input -0 ±0 +0 Display V IN =0 . 0 V Zero Reading Drift — 0.2 1 µV/°C V IN =0 . 0 V 0°C ≤ TA ≤ +70°C NL Linearity Error -1 0.5 +1 Count Max Deviation from Best Straight Line R/O Rollover Error -1 0 +1 Count -V IN =+ VIN EN Noise — 60 — µVP-P VIN =0 V ILK Input Leakage Current — 10 20 pA V IN =0 V CMRR Common Mode Rejection Ratio — 50 — µV/V VCM = ±1V VIN =0 V Scale Factor Temperature Coefficient — 1 — ppm/°C 0 ≤ TA ≤ 7+ 0 ° C External Ref. T emperature Coefficient = 0ppm/°C V CTC Analog Common Temperature Coefficient — 35 100 ppm/°C 250k Ω between Common and V+, 0°C ≤ TA ≤ +70°C VCOM Analog Common Voltage 2.7 2.9 3.35 V 250k Ω between Common and VDD VSD LCD Segment Drive Voltage 4 5 6 V P-P VBD LCD Backplane Drive Voltage 4 5 6 V P-P IDD Power Supply Current — 125 175 µA
DS21477B-page 4 2002 Microchip Technology Inc.
2.0 PIN DESCRIPTION
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 PQFP) Symbol Description 1 NC Positive analog signal input. 2A N A L O G COMMON Establishes the internal analog ground point. Analog common is set to 2.9V below the positive supply COMMON by an internal zener reference circuit. The voltage difference between VDD and analog common can be used to supply the TC826 voltage reference i n p u ta tR E FI N( P i n5 ) . 3 +IN Positive analog signal input. 4 -IN Negative analog signal input. 5 REF IN Reference voltage positive input. Measured relative to analog common. REF IN ≈ Full Scale/2. REF+ Reference capacitor connection. 7C REF- Reference capacitor connection. 8V DD Positive supply terminal. 9V BUF Buffer output. Integration resistor connection. 10 C AZ Negative comparator input. Auto-zero capacitor connection. 11 V INT Integrator output. Integration capacitor connection. 12 V SS Negative supply terminal. 13 OSC1 Oscillator resistor (R OSC) connection. 14 OSC2 Oscillator resistor (R OSC) connection. 15 BP LCD Backplane driver. 16 BAR 0 LCD Segment driver: Bar 0. 17 NC No connection. 18 BAR 1 LCD Segment driver: Bar 1. 19 BAR 2 LCD Segment driver: Bar 2. 20 BAR 3 LCD Segment driver: Bar 3. 21 BAR 4 LCD Segment driver: Bar 4. 22 BAR 5 LCD Segment driver: Bar 5. 23 BAR 6 LCD Segment driver: Bar 6. 24 BAR 7 LCD Segment driver: Bar 7. 25 BAR 8 LCD Segment driver: Bar 8. 26 BAR 9 LCD Segment driver: Bar 9. 27 BAR 10 LCD Segment driver: Bar 10. 28 BAR 11 LCD Segment driver: Bar 11. 29 BAR 12 LCD Segment driver: Bar 12. 30 BAR 13 LCD Segment driver: Bar 13. 31 BAR 14 LCD Segment driver: Bar 14. 32 BAR 15 LCD Segment driver: Bar 15. 33 BAR 16 LCD Segment driver: Bar 16. 34 BAR 17 LCD Segment driver: Bar 17. 35 BAR 18 LCD Segment driver: Bar 18. 36 BAR 19 LCD Segment driver: Bar 19. 37 BAR 20 LCD Segment driver: Bar 20. 38 BAR 21 LCD Segment driver: Bar 21. 39 BAR 22 LCD Segment driver: Bar 22. 40 BAR 23 LCD Segment driver: Bar 23.
2002 Microchip Technology Inc. DS21477B-page 5 TC826 41 BAR 24 LCD Segment driver: Bar 24. 42 BAR 25 LCD Segment driver: Bar 25. 43 BAR 26 LCD Segment driver: Bar 26. 44 BAR 27 LCD Segment driver: Bar 27. 45 BAR 28 LCD Segment driver: Bar 28. 46 BAR 29 LCD Segment driver: Bar 29. 47 BAR 30 LCD Segment driver: Bar 30. 48 NC No connection. 49 BAR 31 LCD Segment driver: Bar 31. 50 BAR 32 LCD Segment driver: Bar 32. 51 BAR 33 LCD Segment driver: Bar 33. 52 BAR 34 LCD Segment driver: Bar 34. 53 BAR 35 LCD Segment driver: Bar 35. 54 BAR 36 LCD Segment driver: Bar 36. 55 BAR 37 LCD Segment driver: Bar 37. 56 BAR 38 LCD Segment driver: Bar 38. 57 BAR 39 LCD Segment driver: Bar 39. 58 BAR 40 LCD Segment driver: Bar 40. 59 OR LCD segment driver that indicated input out-of-range condition. 60 POL- LCD segment driver that indicates input signal is negative.
61 BAR/DOT
Input logic signal that selects BAR or DOT display format. Normally in BAR mode. Connect to VSS through 1MΩ resistor for DOT format. 62 HOLD Input logic signal that prevents display from changing. Pulled high internally to inactive state. Connect to VSS through 1MΩ series resistor for HOLD mode operation. 63 TEST Input logic signal. Sets TC826 to BAR Display mode. BAR 0 to 40, plus OR flash on and off. The POL- LCD driver is on. Pulled high internally to inactive state. Connect to V SS with 1MΩ series resistor to activate. 64 NC No connection. TABLE 2-1: PIN FUNCTION TABLE (CONTINUED) Pin Number (64-Pin PQFP) Symbol Description
DS21477B-page 6 2002 Microchip Technology Inc.
3.0 DETAILED DESCRIPTION
3.1 Dual Slope Conversion Principles
The TC826 is a dual slope, integrating analog-to-digital converter. The conventional dual slope converter mea- surement cycle has two distinct phases: Input Signal Integration Reference Voltage Integration (De-integration) The input signal being converted is integrated for a fixed time period (T SI). Time is measured by counting clock pulses. An opposite polarity constant reference voltage is then integrated until the integrator output voltage returns to zero. The reference integration time is directly proportional to the input signal (T RI) (Figure 3-1). In a simple dual slope converter, a complete conver- sion requires the integrator output to ‘ramp-up’ and ‘ramp-down’. A simple mathematical equation relates the input signal reference voltage and integration time: EQUATION 3-1: FIGURE 3-1: BASIC DUAL SLOPE CONVERTER RC tINT
0 VIN(t)dt = VRTRI
RC∫ Where: VR = Reference Voltage VSI = Signal Integration Time (Fixed) TRI = Reference Voltage Integration Time (Variable) Integrator REF Voltage Switch Driver Phase Control Polarity Control Control Logic Comparator C R Clock Counter Display Analog Input Signal +/– Fixed Signal Integrate Time Variable Reference Integrate Time Integrator Output VIN ≈ 1/2 VFULL SCALE VIN ≈ 1/4 VFULL SCALE
2002 Microchip Technology Inc. DS21477B-page 7 TC826 For a constant VIN: EQUATION 3-2: The dual slope converter accuracy is unrelated to the integrating resistor and capacitor values, as long as they are stable during a measurement cycle. An inher- ent benefit is noise immunity. Noise spikes are inte- grated or averaged to zero during the integration periods. Integrating ADCs are immune to the large con- version errors that plague successive approximation converters in high noise environments. Interfering sig- nals with frequency components at multiples of the averaging period will be attenuated (Figure 3-2). The TC826 converter improves the conventional dual slope conversion technique by incorporating an auto- zero phase. This phase eliminates zero scale offset errors and drift. A potentiometer is not required to obtain a zero output for zero input. FIGURE 3-2: NORMAL MODE REJECTION OF DUAL SLOPE CONVERTER VIN =V R TRI TSI T = Measurement Period 0.1/T 1/T 10/ T Input Frequency Normal Mode Rejection (dB)
DS21477B-page 8 2002 Microchip Technology Inc.
4.0 THEORY OF OPERATION
4.1 Analog Section
In addition to the basic signal integrate and de- integrate cycles discussed above, the TC826 incorpo- rates an auto-zero cycle.This cycle removes buffer amplifier, integrator, and comparator offset voltage error terms from the conversion. A true digital zero reading results without external adjusting potentiome- ters. A complete conversion consists of three cycles: an auto-zero, signal integrate and reference cycle (Figure 4-1 and Figure 4-2).
4.1.1 AUTO-ZERO CYCLE
During the auto-zero cycle, the differential input signal is disconnected from the circuit by opening internal analog gates. The internal nodes are shorted to analog common (internal analog ground) to establish a zero input condition. Additional analog gates close a feed- back loop around the offset voltage error compensation. The voltage level established on C AZ compensates for device offset voltages. The auto-zero cycle length is 19 counts minimum. Unused time in the de-integrate cycle is added to the auto-zero cycle.
4.1.2 SIGNAL INTEGRATION CYCLE
The auto-zero loop is opened and the internal differen- tial inputs connect to +IN and -IN. The differential input signal is integrated for a fixed time period. The TC826 signal integration period is 20 clock periods or counts. The externally set clock frequency is divided by 32 before clocking the internal counters. The integration time period is: EQUATION 4-1: FIGURE 4-1: TC826 ANALOG SECTION Where: FOSC = External Clock Frequency TSI = 32 FOSC x2 0 DE- DE+ DE+ DE- AZ Buffer AZ Comparator Integrator RINT To Digital Section CMPTR REF IN 56 79 1 0 CAZ CINT VDD INT INT ≈ VDD – 2.9V 3+Input Analog Common -INPUT 4 CREF ≈ VDD AZ INT AZ 1µA VDD VDD ≈ 6.3V TC826 Analog Switch From Digital Control Center AZ INT DE+ DE-
2002 Microchip Technology Inc. DS21477B-page 9 TC826 The differential input voltage must be within the device Common mode range when the converter and mea- sured system share the same power supply common (ground). If the converter and measured system do not share the same power supply common, -IN should be tied to analog common. This is the usual connection for battery operated systems. Polarity is determined at the end of signal integrate signal phase. The sign bit is a true polarity indication, in that signals less than 1LSB are correctly determined. This allows precision null detection limited only by device noise and system noise.
4.1.3 REFERENCE INTEGRATE CYCLE
The final phase is reference integrate or de-integrate. -IN is internally connected to analog common and +IN is connected with the correct polarity to cause the inte- grator output to return to zero. The time required for the output to return to zero is proportional to the input sig- nal and is between 0 and 40 counts. The digital reading displayed is: EQUATION 4-2: FIGURE 4-2: CONVERSION HAS THREE PHASES 20 = VIN VREF Internal System Clock (FSYS) Auto-Zero Phase (AZ) Signal Integrate Phase (SI) Reference Integrate Phase (RI) (De-integrate) Integrator Output Internal Data Latch Update Signal
19 Counts
41 Counts
TI TD ≈ VIN Number of Counts Proportional to V IN One Conversion Cycle = 80 Counts (T CONV = 80 X 1 FSYS ) True Zero Crossing Sign Bit Determined Zero Crossing Detected Analog Common Potential
DS21477B-page 10 2002 Microchip Technology Inc.
4.2 System Timing
The oscillator frequency is divided by 32 prior to clock- ing the internal counters. The three-phase measure- ment cycle takes a total of 80 clock pulses. The 80 count cycle is independent of input signal magnitude. Each phase of the measurement cycle has the follow- ing length: Auto-Zero Phase: 19 to 59 Counts For signals less than full scale, the auto-zero is assigned the unused reference integrate time period. Signal Integrate: 20 Counts This time period is fixed. The integration period is: EQUATION 4-3: Reference Integrate: 0 to 41 Counts
4.3 Reference Voltage Selection
A full scale reading requires the input signal be twice the reference voltage. The reference potential is mea- sured between REF IN (Pin 5) and ANALOG COMMON (Pin 2). TABLE 4-1: The internal voltage reference potential available at analog common will normally be used to supply the converter’s reference. This potential is stable when- ever the supply potential is greater than approximately 7V. In applications where an externally generated refer- ence voltage is desired, refer to Figure 4-3. The reference voltage is adjusted with a near full scale input signal. Adjust for proper LCD display read out. FIGURE 4-3: EXTERNAL REFERENCE
4.4 Components Value Selection
4.4.1 INTEGRATING RESISTOR (R INT)
The desired full scale input voltage and output current capability of the input buffer and integrator amplifier set the integration resistor value. The internal class A out- put stage amplifiers will supply a 1µA drive current with minimal linearity error. R INT is easily calculated for a 1µA full scale current: EQUATION 4-4:
4.4.2 INTEGRATING CAPACITOR (C INT)
The integrating capacitor should be selected to maxi- mize integrator output swing. The integrator output will s w i n gt ow i t h i n0 . 4 Vo fV S+o rV S- without saturating. The integrating capacitor is easily calculated: EQUATION 4-5: The integrating capacitor should be selected for low dielectric absorption to prevent rollover errors. Polypro- pylene capacitors are suggested.
4.4.3 AUTO-ZERO CAPACITOR (C AZ)
CAZ should be 2-3 times larger than the integration capacitor. A polypropylene capacitor is suggested. Typ- ical values from 0.14µF to 0.068µFa r es a t i s f a c t o r y .
4.4.4 REFERENCE CAPACITOR (C REF)
A1 µF capacitor is suggested. Low leakage capacitors, such as polypropylene, are recommended. Several capacitor/resistor combinations for common full scale input conditions are given in Table 4-2. Required Full Scale Voltage V REF 20mV 10mV 2V 1V TSI =2 0 FOSC Where FOSC is the externally set clock frequency. TC826 REF IN ANALOG COMMON 2.50V Reference (b) MCP1525 1µF Where VFS = Full Scale Analog Input RINT = Full Scale Voltage(V) 1x1 0–6 VFS 1x1 0–6 Where: VINT = Integrator Swing FOSC = Oscillator Frequency CINT = VFS RINT 640 FOSC xV INT
2002 Microchip Technology Inc. DS21477B-page 11 TC826 TABLE 4-2: SUGGESTED COMPONENT VALUES
4.5 Differential Signal Inputs
The TC826 is designed with true differential inputs and accepts input signals within the input stage Common mode voltage range (V CM). The typical range is V+ -1 to V- +1V. Common mode voltages are removed from the system when the TC826 operates from a battery or floating power source (isolated from measured sys- tem) and -IN is connected to analog common (V COM). In systems where Common mode rejection ratio mini- mizes error. Common mode voltages do, however, affect the integrator output level. Integrator output sat- uration must be prevented. A worse case condition exists if a large positive V CM exists in conjunction with a full scale negative differential signal. The negative signal drives the integrator output positive along with V CM. For such applications, the integrator output swing can be reduced below the recommended 2V full scale swing. The integrator output will swing within 0.3V of V DD or VSS without increased linearity error.
4.6 Digital Section
The TC826 contains all the segment drivers necessary to drive a liquid crystal display (LCD). An LCD back- plane driver is included. The backplane frequency is the external clock frequency divided by 256. A 430k Ω OSC gets the backplane frequency to approximately 55Hz, with a 5V nominal amplitude. When a segment driver is in phase with the backplane signal, the seg- ment is ‘OFF’. An out-of-phase segment drive signal causes the segment to be ‘ON’ or visible. This AC drive configuration results in negligible DC voltage across each LCD segment. This insures long LCD display life. The polarity segment drive, -POL, is ‘ON’ for negative analog inputs. If +IN and -IN are reversed, this indicator would reverse. The TC826 transfer function is shown in Figure 4-4. FIGURE 4-4: TRANSFER FUNCTION
4.7 BAR/DOT Input (Pin 61)
The BAR/DOT input allows the user to select the dis- play format. The TC826 powers up in the BAR mode. Select the DOT display format by connecting BAR/DOT to the negative supply (Pin 12) through a 1MΩ resistor.
4.8 HOLD Input (Pin 62)
The TC826 data output latches are not updated at the end of each conversion if HOLD is tied to the negative supply (Pin 12) through a 1M Ω resistor. The LCD dis- play continuously displays the previous conversion results. The HOLD pin is normally pulled high by an internal pull-up.
4.9 TEST Input (Pin 63)
The TC826 enters a Test mode with the TEST input connected to the negative supply (Pin 12). The connec- tion must be made through a 1M Ω resistor. The TEST input is normally internally pulled high. A low input sets the output data latch to all ones. The BAR Display mode is set. The 41 LCD output segments (zero plus 40 data segments) and over range annunciator flash on and off at 1/4 the conversion rate. The polarity annun- ciator (POL-) segment will be on, but not flashing.
4.10 Over Range Display Operation
(OR, Pin 59) An out-of-range input signal will be indicated on the LCD display by the OR annunciator driver (Pin 59) becoming active. In the BAR display format, the 41 bar segments and the over range annunciator, OR, will flash ON and OFF. The f l a s hr a t ei so nf o u r t ht h ec o n v e r s i o nr a t e( F OSC/2560). In the DOT Display mode, OR flashes and all other data segment drivers are off. Comp. Full Scale VREF ≈ 1V 2mV Full Scale VREF ≈ 100V 20mV Full Scale VREF ≈ 10V RINT 2MΩ 200kΩ 20kΩ CINT 0.033µF0 . 0 3 3 µF0 . 0 3 3 µF CREF 1µF1 µF1 µF CAZ 0.068µF0 . 0 6 8 µF1 . 1 4 µF ROSC 430kΩ 430kΩ 430kΩ Note: Approximately 5 conversions/second. -1-2 1 2 3 39 39.5 40 40.5 -0.5 0.5 Digital Display Over Range Indication Analog Input (X VFS 40 )
DS21477B-page 12 2002 Microchip Technology Inc.
4.11 Polarity Indication (POL-, Pin 60)
The TC826 converts and displays data for positive and negative input signals. The POL LCD segment driver (Pin 60) is active for negative signals.
4.12 Oscillator Operation
The TC826 external oscillator frequency, F OSC,i ss e t by resistor R OSC connected between pins 13 and 14. The oscillator frequency versus resistance curve is shown in Figure 4-5. FIGURE 4-5: OSCILLATOR FREQUENCY VS. R OSC FOSC is divided by 32 to provide an internal system clock, FYSY . Each conversion requires 80 internal clock cycles. The internal system clock is divided by 8 to provide the LCD backplane drive frequency. The dis- play flash rate during an input out-of-range signal is set by dividing FSYS by 320. The internal oscillator may be bypassed by driving OSC1 (Pin 13) with an external signal generator. OSC2 (Pin 14) should be left unconnected. The oscillator should swing from V DD to VSS in single supply operation (Figure 4-6). In dual supply operation, the signal should swing from power supply ground to V DD. FIGURE 4-6: EXTERNAL OSCILLATOR CONNECTION
4.13 LCD Display Format
The input signal can be displayed in two formats (Figure 4-7). The BAR/DOT input (Pin 61) selects the format. The TC826 measurement cycle operates identically for either mode. FIGURE 4-7: DISPLAY OPTION FORMATS 0 2468 1 0 1 2 1 4 1 6 1 8 2 0 TA = 25°C VDD to VSS = 9V ROSC (X 100kΩ) FOSC (kHz) CONV (CONV/SEC) TC826 12 13 OSC1 OSC2 0.1µf External Oscillator A. Single 9V Supply TC826 B. Dual Supply 0.1µf
13 Oscillator
VDD = 5V VSS = 5V Bar 4 Off Off Bar 3 Off Off Bar 2 Off On Bar 1 Off On Bar 0 Bar 4 Bar 3 Bar 2 Bar 1 Bar 0 On Off Off Off Off On On 1. Input = 0 A. BAR Mode Off Off On Off Off 1. Input = 0 B. DOT Mode 2. Input = 5% of Full Scale 2. Input = 5% of Full Scale
2002 Microchip Technology Inc. DS21477B-page 13 TC826
4.14 BAR Format
The TC826 powers up in the BAR mode. BAR/DOT is pulled high internally. This display format is similar to a thermometer display. All bars/LCD segments including zero, below the bar/LCD segment equaling the input signal level, are on. A half scale input signal, for exam- ple, would be displayed with BAR 0 to BAR 20 on.
4.15 DOT Format
By connecting BAR/DOT to VSS through a 1MΩ resis- tor, the DOT mode is selected. Only the BAR LCD seg- ment equaling the input signal is on. The zero segment is on for zero input. This mode is useful for moving cursor or ‘needle’ appli- cations.
4.16 LCD Displays
Most end products will use a custom LCD display for final production. Custom LCD displays are low cost and available from all manufacturers. The TC826 interfaces to non-multiplexed LCD displays. A backplane driver is included on-chip. To speed initial evaluation and prototype work, a stan- dard TC826 LCD display is available from Varitronix. Varitronix Ltd. LCDs 4/F Liven House 61-63 King Yip Street Kwun Tong, Kowloon Hong Kong Tel: (852)2389-4317 Fax: (852)2343-9555 USA Office: VL Electronics / Varitronix 3250 Wilshire Blvd., Suite 901 Los Angeles, CA 90010 Tel: (213) 738-8700 Fax: (213) 738-5340 Part No.: VBG-413-DP Other standard LCD displays suitable for development work are available in both linear and circular formats. One manufacturer is: UCE Inc.
24 Fitch Street
Norwalk, CT 06855 Tel: 203/838-7509 Part No. 5040: 50 segment circular display with 3-digit numeric scale. Part No. 5020: 50 segment linear display.
4.17 LCD Backplane Driver (BP , Pin 15)
Additional drive electronics are not required to interface the TC826 to an LCD display. The TC826 has an on- chip backplane generator and driver. The backplane frequency is: FBP = F OSC/256 Figure 4-8 gives typical backplane driver rise/fall time versus backplane capacitance. FIGURE 4-8: BACKPLANE DRIVE RISE/ FALL TIME VS. CAPACITANCE
4.18 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 Tel: 415/856-9332 Telex: 910/373-2060 ‘BQ’ Socket Part No.: IC51-064-042 BQ 0 123456780 1 0 Backplane Capacitance (X 100pf) Rise/Fall Time (X 100ns) TA = 25°C VS = 9V
DS21477B-page 14 2002 Microchip Technology Inc.
5.0 PACKAGING INFORMATION
5.1 Package Marking Information
Package marking data not available at this time.
5.2 Taping Form
5.3 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)
2002 Microchip Technology Inc. DS21477B-page 15 TC826 NOTES:
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2002 Microchip Technology Inc. DS21477B-page 17 TC826 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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Itasca, IL 60143 Tel: 630-285-0071 Fax: 630-285-0075 Dallas
4570 Westgrove Drive, Suite 160
Addison, TX 75001 Tel: 972-818-7423 Fax: 972-818-2924 Detroit Tri-Atria Office Building
32255 Northwestern Highway, Suite 190
Farmington Hills, MI 48334 Tel: 248-538-2250 Fax: 248-538-2260 Kokomo 2767 S. Albright Road Kokomo, Indiana 46902 Tel: 765-864-8360 Fax: 765-864-8387 Los Angeles
18201 Von Karman, Suite 1090
Irvine, CA 92612 Tel: 949-263-1888 Fax: 949-263-1338 New York
150 Motor Parkway, Suite 202
Hauppauge, NY 11788 Tel: 631-273-5305 Fax: 631-273-5335 San Jose Microchip Technology Inc.
2107 North First Street, Suite 590
San Jose, CA 95131 Tel: 408-436-7950 Fax: 408-436-7955 Toronto
6285 Northam Drive, Suite 108
Mississauga, Ontario L4V 1X5, Canada Tel: 905-673-0699 Fax: 905-673-6509 ASIA/PACIFIC Australia Microchip Technology Australia Pty Ltd Suite 22, 41 Rawson Street Epping 2121, NSW Australia Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 China - Beijing Microchip Technology Consulting (Shanghai) Co., Ltd., Beijing Liaison Office Unit 915 Bei Hai Wan Tai Bldg. No. 6 Chaoyangmen Beidajie Beijing, 100027, No. China Tel: 86-10-85282100 Fax: 86-10-85282104 China - Chengdu Microchip Technology Consulting (Shanghai) Co., Ltd., Chengdu Liaison Office Rm. 2401, 24th Floor, Ming Xing Financial Tower No. 88 TIDU Street Chengdu 610016, China Tel: 86-28-6766200 Fax: 86-28-6766599 China - Fuzhou Microchip Technology Consulting (Shanghai) Co., Ltd., Fuzhou Liaison Office Unit 28F, World Trade Plaza No. 71 Wusi Road Fuzhou 350001, China Tel: 86-591-7503506 Fax: 86-591-7503521 China - Shanghai Microchip Technology Consulting (Shanghai) Co., Ltd. Room 701, Bldg. B Far East International Plaza No. 317 Xian Xia Road Shanghai, 200051 Tel: 86-21-6275-5700 Fax: 86-21-6275-5060 China - Shenzhen Microchip Technology Consulting (Shanghai) Co., Ltd., Shenzhen Liaison Office Rm. 1315, 13/F, Shenzhen Kerry Centre, Renminnan Lu Shenzhen 518001, China Tel: 86-755-2350361 Fax: 86-755-2366086 Hong Kong Microchip Technology Hongkong Ltd. Unit 901-6, Tower 2, Metroplaza
223 Hing Fong Road
Kwai Fong, N.T., Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 India Microchip Technology Inc. India Liaison Office Divyasree Chambers
1 Floor, Wing A (A3/A4)
No. 11, O’Shaugnessey Road Bangalore, 560 025, India Tel: 91-80-2290061 Fax: 91-80-2290062 Japan Microchip Technology Japan K.K. Benex S-1 6F 3-18-20, Shinyokohama Kohoku-Ku, Yokohama-shi Kanagawa, 222-0033, Japan Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Korea Microchip Technology Korea 168-1, Youngbo Bldg. 3 Floor Samsung-Dong, Kangnam-Ku Seoul, Korea 135-882 Tel: 82-2-554-7200 Fax: 82-2-558-5934 Singapore Microchip Technology Singapore Pte Ltd.
200 Middle Road
#07-02 Prime Centre Singapore, 188980 Tel: 65-6334-8870 Fax: 65-6334-8850 Taiwan Microchip Technology Taiwan 11F-3, No. 207 Tung Hua North Road Taipei, 105, Taiwan Tel: 886-2-2717-7175 Fax: 886-2-2545-0139 EUROPE Denmark Microchip Technology Nordic ApS Regus Business Centre Lautrup hoj 1-3 Ballerup DK-2750 Denmark Tel: 45 4420 9895 Fax: 45 4420 9910 France Microchip Technology SARL Parc d’Activite du Moulin de Massy
43 Rue du Saule Trapu
91300 Massy, France
D-81739 Munich, Germany Tel: 49-89-627-144 0 Fax: 49-89-627-144-44 Italy Microchip Technology SRL Centro Direzionale Colleoni Palazzo Taurus 1 V. Le Colleoni 1
20041 Agrate Brianza
Milan, Italy Tel: 39-039-65791-1 Fax: 39-039-6899883 United Kingdom Arizona Microchip Technology Ltd.
505 Eskdale Road
Berkshire, England RG41 5TU Tel: 44 118 921 5869 Fax: 44-118 921-5820 03/01/02 *D S2 14 77 B* WORLDWIDE SALES AND SERVICE