TC510CPF

TC500 TELCOM | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 17

Technical content

3-19TELCOM SEMICONDUCTOR, INC. PRECISION ANALOG FRONT ENDS

FEATURES

n Precision (up to 17 Bits) A/D Converter "Front End" n 3-Pin Control Interface to Microprocessor n Flexible: User Can Trade-Off Conversion Speed for Resolution n Single Supply Operation (TC510/514) n 4 Input, Differential Analog MUX (TC514) n Automatic Input Voltage Polarity Detection TC510/514: 18mW n Directly Accepts Bipolar and Differential Input Signals GENERAL DESCRIPTION The TC500/500A/510/514 family are precision analog front ends that implement dual slope A/D converters having a maximum resolution of 17 bits plus sign. As a minimum, each device contains the integrator, zero crossing compara- tor and processor interface logic. The TC500 is the base (16 bit max) device and requires both positive and negative power supplies. The TC500A is identical to the TC500, except it has improved linearity allowing it to operate to a maximum resolution of 17 bits. The TC510 adds an on- board negative power supply converter for single supply operation. The TC514 adds both a negative power supply converter and a 4 input differential analog multiplexer. Each device has the same processor control interface consisting of 3 wires: control inputs A and B and zero- crossing comparator output (CMPTR). The processor ma- nipulates A, B to sequence the TC5xx through four phases of conversion: Auto Zero, Integrate, Deintegrate and Inte- grator Zero. During the Auto Zero phase, offset voltages in the TC5xx are corrected by a closed-loop feedback mecha- nism. The input voltage is applied to the integrator during the Integrate phase. This causes an integrator output dv/dt directly proportional to the magnitude of the input voltage. The higher the input voltage, the greater the magnitude of the voltage stored on the integrator during this phase. At the start of the Deintegrate phase, an external voltage reference is applied to the integrator, and at the same time, the external host processor starts its on-board timer. The processor main- FUNCTIONAL BLOCK DIAGRAM LEVEL SHIFT CONTROL LOGIC ANALOG SWITCH CONTROL SIGNALS ACOM + VREF – BUF C AZ BUFFER INTEGRATORSW R SW IZ CMPTR 1 CMPTR 2 CMPTR OUTPUT DGND CONTROL LOGIC SW 1 TC500 TC500A TC510 TC514 C REF C REF SW R C REF C AZ R INT C INT C INT SW RI +SW RI +SW RI –SW RI SW Z SW I SW Z VS OSC PHASE DECODING LOGIC POLARITY DETECTION DC-TO-DC CONVERTER (TC510 & TC514) A B 0 0 ZERO INTEGRATOR OUTPUT 0 1 AUTO-ZERO 1 0 SIGNAL INTEGRATE 1 1 DEINTEGRATE VREF VOUT C OUT 1.0µF 1.0µF VSS SW I BA A0 A1 DIF. MUX (TC514) CH1 + CH2 + CH3 + CH4 + CH1 – CH2 – CH3 – CH4 – CAP – CAP + (TC500 TC500A) CONVERTER STATE TC500 TC500A TC510 TC514 TC500/A/510/514-3 10/3/96

ORDERING INFORMATION

Part No. Package Temp. Range TC500ACOE 16-Pin SOIC 0 °C to +70°C TC500ACPE 16-Pin Plastic DIP (Narrow) 0 °C to +70°C TC500COE 16-Pin SOIC 0 °C to +70°C TC500CPE 16-Pin Plastic DIP (Narrow) 0 °C to +70°C TC510COG 24-Pin SOIC 0 °C to +70°C TC510CPF 24-Pin Plastic DIP (300 Mil.) 0 °C to +70°C TC514COI 28-Pin SOIC 0 °C to +70°C TC514CPJ 28-Pin Plastic DIP (300 Mil.) 0 °C to +70°C TC500EV Evaluation Kit for TC500/500A/510/514 EVALUATION KIT AVAILABLE

3-20 TELCOM SEMICONDUCTOR, INC. * Static-sensitive device. Unused devices must be stored in conductive material. Protect devices from static discharge and static fields. Stresses above those listed under "Absolute Maximum Ratings" may cause perma- nent 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. GENERAL DESCRIPTION (Cont.) tains this state until a transition occurs on the CMPTR output, at which time the processor halts its timer. The resulting timer count is the converted analog data. Integrator Zero (the final phase of conversion) removes any residue remain- ing in the integrator in preparation for the next conversion. The TC500/500A/510/514 offer high resolution (up to 17 bits) superior 50Hz/60Hz noise rejection, low power opera- tion, minimum I/O connections, low input bias currents and lower cost compared to other converter technologies having similar conversion speeds. ABSOLUTE MAXIMUM RATINGS * TC510/514 Positive Supply Voltage TC500/500A Supply Voltage TC500/500A Positive Supply Voltage TC500/500A Negative Supply Voltage Analog Input Voltage (V+IN or V_ ELECTRICAL CHARACTERISTICS: TC510/514: VDD = +5V, TC500/500A: VS = ±5V unless otherwise specified. CAZ = CREF = 0.47 µF TA = +25°C TA = 0°C to +70°C Symbol Parameter Test Conditions Min Typ Max Min Typ Max Unit Analog Resolution Note 1 60 — — — — — µV with Auto Zero Phase TC500A — — 0.003 — 0.003 0.009 NL Best Case Straight TC500/510/514, Notes 1, 2, — 0.003 0.008 — — — % F.S. Line Linearity TC500A — — 0.005 — — — % F.S. ZS TC Zero-Scale Over Operating — — — 1 2 µV/°C Temperature Temperature Range Coefficient SYE Full-Scale Symmetry Note 3 — 0.01 — — 0.03 — % F.S. Error (Roll-Over Error) FS TC Full-Scale Temperature Over Operating — — — — 10 — ppm/°C Coefficient Temperature Range External Reference TC = 0ppm/°C IIN Input Current V IN = 0V — 6 — — — — pA VCMR Common-Mode V SS +1.5 — V DD – 1.5 VSS +1.5 — V DD – 1.5 V Voltage Range Integrator Output Swing V SS +0.9 — V DD – 0.9 VSS +0.9 — V SS +0.9 V Analog Input Signal RangeACOM = GND = 0V V SS +1.5 — V DD – 1.5 VSS +1.5 — V SS +1.5 V VREF Voltage Reference Range V REF V+REF VSS +1 — V DD – 1 V SS +1 — V DD – 1 V PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514

3-21TELCOM SEMICONDUCTOR, INC. PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514 ELECTRICAL CHARACTERISTICS: (Cont.) TA = +25°C TA = 0°C to +70°C Symbol Parameter Test Conditions Min Typ Max Min Typ Max Unit Digital VOH Comparator Logic 1, I SOURCE = 400µA4 — — 4 — — V Output High VOL Comparator Logic 0, I SINK = 2.1mA — — 0.4 — — 0.4 V Output Low VIH Logic 1, Input High Voltage 3.5 — — 3.5 — — V VIL Logic 0, Input Low Voltage — — 1 — — 1 V IL Logic Input Current Logic 1 or 0 — — — — 0.3 — µA tD Comparator Delay — 2 — — 3 — µsec Multiplexer (TC514 Only) Maximum Input Voltage V DD = 5V – 2.5 — 2.5 – 2.5 — 2.5 V R DS ON Drain/Source ON Resistance VDD = 5V — 6 10 — — — k Ω Power (TC510/514 Only) IS Supply Current V DD = 5V, A = 1, B = 1 — 1.8 2.4 — — 3.5 mA PD Power Dissipation V DD = 5V — 18 — — — — mW VDD Positive Supply 4.5 — 5.5 4.5 — 5.5 V Operating Voltage Range R OUT Operating Source Resistance IOUT = 10mA — 60 85 — — 100 Ω Oscillator Frequency (Note 3) — 100 — — — — kHz IOUT Maximum Current Out V DD = 5V — — – 10 — — – 10 mA Power (TC500/500A Only) IS Supply Current V S = ±5V, A = B = 1 — 1 1.5 — — 2.5 mA PD Power Dissipation V DD = 5V, VSS = – 5V — 10 — — — — mW VDD Positive Supply 4.5 — 7.5 4.5 — 7.5 V Operating Voltage Range VSS Negative Supply – 4.5 — – 7.5 – 4.5 — – 7.5 V Operating Voltage Range NOTES: 1. Integrate time ≥ 66msec, auto-zero time ≥ 66msec, VINT (peak) ≈ 4V. 2. End point linearity at ±1/4, ±1 /2, ±3/4 F.S. after full-scale adjustment. 3. Roll-over error is related to CINT, CREF , CAZ characteristics.

3-22 TELCOM SEMICONDUCTOR, INC. CAP DGND V A B C REF C INT C AZ BUF ACOM N/C N/C N/C TC510CPF CREF REF V REF VOUT – VOUT VOUT V C REF C INT C AZ BUF ACOM N/C N/C N/C CREF REF V REF VDD OSC CMPTR OUT VIN –VIN N/C N/C CAP + CAP DGND A B VDD OSC CMPTR OUT VIN –VIN N/C N/C CAP + TC510COG CAP DGND V A B C REF C INT C AZ BUF ACOM CH4 – CH3 – CH2 – TC514CPJ CREF REF V REF VDD OSC CMPTR OUT CAP + CH1 – N/C CH1 + CH2 + CH3 + CH4+ V VOUT C REF C INT C AZ BUF ACOM CREF REF V REF CAP DGND VDD OSC CMPTR OUT CAP + TC514COI N/C CH4 – CH3 – CH2 – CH1 – A B CH1 + CH2 + CH3 + CH4 + 13BUF CMPTR OUT A VSS C INT DIGITAL GND B VDD ACOM ACOM TC500/ TC500A CPE VIN VIN VREF VREF C REF C REF C AZ TC500/ TC500A COE BUF VSS C INT –VREF C REF C REF C AZ CMPTR OUT A DIGITAL GND B VDD VIN VIN VREF PIN CONFIGURATIONS PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514

3-23TELCOM SEMICONDUCTOR, INC. PIN DESCRIPTION Pin No Pin No Pin No (TC500, 500A) (TC510) (TC514) Symbol Description 122 C INT Integrator output. Integrator capacitor connection. 2 Not Used Not Used V SS Negative power supply input (TC500/500A only). 333 C AZ Auto-zero input. The Auto-zero capacitor connection. 4 4 4 BUF Buffer output. The Integrator capacitor connection. 5 5 5 ACOM This pin is grounded in most applications. It is recommended that ACOM and the input common pin (V–IN or C –HN ) be within the analog common mode range (CMR). 666 C –REF Input. Negative reference capacitor connection. 777 C +REF Input. Positive reference capacitor connection. 888 V –REF Input. External voltage reference (–) connection. 999 V +REF Input. External voltage reference (+) connection. 10 15 Not Used V –IN Negative analog input. 11 16 Not Used V +IN Positive analog input. 12 18 22 A Input. Converter phase control MSB. (See input B.) 13 17 21 B Input. Converter phase control LSB. The states of A, B place the TC5xx in one of four required phases. A conversion is complete when all four phases have been executed: 00: Integrator Zero Phase control input pins: AB =01: Auto Zero 10: Integrate 11: Deintegrate 14 19 23 CMPTR OUT Zero crossing comparator output. CMPTR is HIGH during the Integration phase when a positive input voltage is being integrated and is LOW when a negative input voltage is being integrated. A HIGH-to-LOW transition on CMPTR signals the processor that the Deintegrate phase is completed. CMPTR is undefined during the Auto-Zero phase. It should be monitored to time the Integrator Zero phase (see text). 15 23 27 DGND Input. Digital ground. 16 21 25 V DD Input. Power supply positive connection. 22 26 CAP + Input. Negative power supply converter capacitor (+) connection. 24 28 CAP – Input. Negative power supply converter capacitor (–) connection. 11 V –OUT Output. Negative power supply converter output and reservoir capacitor connection. This output can be used to power other devices in the circuit requiring a negative bias voltage. 20 24 OSC Oscillator control input. The negative power supply converter normally runs at a frequency of 100kHz. The converter oscillator frequency can be slowed down (to reduce quiescent current) by connecting an external capacitor between this pin and V DD . (See Typical Character- istics Curves). 18 CH1 + Positive analog input pin. MUX channel 1. 13 CH1 – Negative analog input pin. MUX channel 1. 17 CH2 + Positive analog input pin. MUX channel 2. 12 CH2 – Negative analog input pin. MUX channel 2. 16 CH3 + Positive analog input pin. MUX channel 3. 11 CH3 – Negative analog input pin. MUX channel 3. 15 CH4 + Positive analog input pin. MUX channel 4. PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514

3-24 TELCOM SEMICONDUCTOR, INC. Figure 2. Basic Dual-Slope Converter 20 A0 Multiplexer input channel select input LSB. (See A1). 19 A1 Multiplexer input channel select input MSB. input signal Integration and reference voltage Deintegration. (having a polarity opposite that of VIN) to the integrator input. the magnitude of the applied input voltage.

3-26 TELCOM SEMICONDUCTOR, INC. within the device's common-mode range VCMR . polarity; CMPTR = 0 for negative polarity. voltage range, common-mode rejection is typically 80dB. no less than 1.5V from either supply. of either supply without loss of linearity. common, a common-mode voltage exists in the system. This signal is rejected by the excellent CMR of the converter. –IN is not connected to analog common. capacitor in comparison to the stray capacitance. microprocessor I/O port or external logic. Table 1. Internal Analog Gate Status *Assumes a positive polarity input signal. SW–RI would be closed for a negative input signal.

3-27TELCOM SEMICONDUCTOR, INC. Figure 5. Comparator Output mined by the microprocessor controlling the conversion. processor that the conversion is complete.

3-28 TELCOM SEMICONDUCTOR, INC. PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514

APPLICATIONS

The procedure outlined below allows the user to arrive at values for the following TC5xx design variables: (1) Integration Phase Timing (2) Integrator Timing Components (RINT, CINT) (3) Auto Zero and Reference Capacitors (4) Voltage Reference Select Integration Time Integration time must be picked as a multiple of the period of the line frequency. For example, t INT times of 33msec, 66msec and 132msec maximize 60Hz line rejec- tion. D INT and IZ Phase Timing The duration of the DINT phase is a function of the amount of voltage stored on the integrator during TINT, and the value of V REF . The DINT phase must be initiated imme- diately following INT and terminated when an integrator output zero-crossing is detected. In general, the maximum number of counts chosen for DINT is twice that of INT (with V REF chosen at VIN (max)/2). Calculate Integrating Resistor (RINT) The desired full-scale input voltage and amplifier output current capability determine the value of RINT. The buffer and integrator amplifiers each have a full-scale current of 20µA. The value of R INT is therefore directly calculated as follows: R INT(in MΩ ) = VIN MAX where: VIN MAX = Maximum input voltage (full count voltage) RINT =Integrating Resistor (in MΩ ) For loop stability, RINT should be ≥ 50kΩ . Select Reference (CREF ) and Auto Zero (CAZ ) Capacitors C REF and CAZ must be low leakage capacitors (such as polypropylene). The slower the conversion rate, the larger the value C REF must be. Recommended capacitors for CREF and CAZ are shown in Table 1. Larger values for CAZ and C REF may also be used to limit roll-over errors. Table 1. CREF and CAZ Selection *WIMA Corp. listing on the last page of this data sheet. capacitor is calculated using the following equation. capacitors may also be used in less critical applications. Table 2. Recommend Capacitor for CINT *WIMA Corp. listing on the last page of this data sheet.

3-30 TELCOM SEMICONDUCTOR, INC. Figure 8. Typical Dual Slope A/D Converter System Timing

0 FOR NEGATIVE INPUT

1 FOR POSITIVE INPUT

underway, the comparator will be in a defined state. timing this phase. The typical delay is specified to be 2µsec. Integrator Output Zero phase.

3-31TELCOM SEMICONDUCTOR, INC. PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514 USING THE TC510/514 Negative Supply Voltage Converter (TC510, TC514) A capacitive charge pump is employed to invert the voltage on VDD for negative bias within the TC510/514. This voltage is also available on the V–OUT pin to provide negative bias elsewhere in the system. Two external capacitors are required to perform the conversion. Timing is generated by an internal state machine driven from an on-board oscillator. During the first phase, capacitor C F is switched across the power supply and charged to V+ This charge is transferred to capacitor C–OUT during the second phase. The oscillator normally runs at 100kHz to ensure minimum output ripple. This frequency can be re- duced by placing a capacitor from OSC to V DD . The relation- ship between the capacitor value is shown in the typical characteristics curves at the end of this data sheet. Analog Input Multiplexer (TC514) The TC514 is equipped with a four input differential analog multiplexer. Input channels are selected using select inputs (A1, A0). These are high-true control signals (i.e., channel 0 is selected when (A1, A0 = 00). EVALUATION KIT (TC500EV) The TC500EV consists of a pre-assembled, 4 inch by 6 inch printed circuit board that connects to the serial port of any PC or dumb terminal. Design software is also included. TC500EV helps reduce design time and optimize converter performance. Please contact your local TelCom representa- tive for more information. Design Example Given: Required Resolution: 16 Bits (65,536 counts). Maximum V IN: ±2V Power Supply Voltage: +5V 60Hz System Step 1: Pick integration time (t INT) as a multiple of the line frequency: 1/60Hz = 16.6msec. Use 4x line frequency = 66msec Step 2: Calculate RINT R INT (in MΩ ) = VINMAX /20 = 2/20 = 100kΩ Step 3: Calculate CINT for maximum (4V) integrator output swing: C INT (in µF) = (tINT) (20 x 10 –6) / (VS – 0.9) = .32µF (use closest value: 0.33µF) NOTE: TelCom recommended capacitor: WIMA p/n: MK12 .33/63/10 Step 4: Choose CREF and CAZ based on conversion rate: Conversions/sec = 1/(tAZ + tINT + 2 tINT + 2msec) = 1/(66msec + 66msec +132msec+2msec) = 3.7 conversions/sec From which CAZ = CREF = 0.22µF (see Table 1) NOTE: TelCom recommended capacitor: WIMA p/n: MK12 .22/63/10 Step 5: Calculate VREF VREF (in Volts) = (VS – 0.9) (CINT) (RINT) 2(tINT) = 1.025V

3-34 TELCOM SEMICONDUCTOR, INC. TYPICAL PERFORMANCE CHARACTERISTICS OF INTERNAL DC-TO-DC CONVERTER LOAD CURRENT (mA) OUTPUT CURRENT (mA) 0 1 02 03 04 0 50 60 70 0 6 8 10 421 4 1 6 1 8 12 2080 OUTPUT VOLTAGE (V) Output Voltage vs Load Current OUTPUT VOLTAGE (V) Output Voltage vs. Output Current OSCILLATOR CAPACITANCE (pF) 100 11 0 100 1000 OSCILLATOR FREQUENCY (kHz) Oscillator Frequency vs. Capacitance LOAD CURRENT (mA) 0 3 45612 78 9 1 0 100 125 150 175 200 OUTPUT RIPPLE (mV PK-PK) Output Ripple vs. Load Current TEMPERATURE ( °C) 100 –50 02 5–25 50 75 100 OUTPUT SOURCE RESISTANCE ( Ω ) Output Source Resistance vs. Temperature TA = 25°C V+ = 5V TA = +25°C V+ = 5V TA = 25°C Slope 60Ω V+ = 5V, TA = 25°C Osc. Freq. = 100kHz CAP = 1µF CAP = 10µF V+ = 5V IOUT = 10mA TEMPERATURE ( °C) 125 150 100 –50 02 5–25 50 75 125 100 OSCILLATOR FREQUENCY (kHz) Oscillator Frequency vs. Temperature V+ = 5V PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514

3-35TELCOM SEMICONDUCTOR, INC. Australia: ADILAM ELECTRONICS (PTY.) LTD. P.O. Box 664

3 Nicole Close

Tel.: 3-761-4466 Fax: 3-761-4161 Canada: R-THETA INC. 130 Matheson Blvd. East, Unit 2 Mississauga, Ont. L4Z1Y6 Tel.: 905-890-0221 Fax: 905-890-1628 Hong Kong: REALTRONICS CO. LTD. E-3, Hung-On Building 2, King's Road Tel.: 25-70-1151 Fax: 28-06-8474 India: SUSAN AGENCIES P.O. Box 2138 Srirampuram P.O. Bangalore-560 021 Tel.: 080-332-0662 Fax: 080-332-4338 Israel: M.G.R. TECHNOLOGY P.O. Box 2229 Rehavot 76121 Tel.: 972-841-1719 Fax: 972-841-4178 Japan: UNIDUX INC. 5-1-21, Kyonan-Cho Musashino-Shi Tokyo 180 Tel.: 04-2232-4111 Fax: 04-2232-0331 Malaysia: MA ELECTRONICS (M) SDN BHD 346-B Jalan Jelutong

11600 Penang

Tel.: 604-281-4518 Fax: 604-281-4515 Singapore: MICROTRONICS ASSOC. (PTE.) LTD. 8, Lorong Bakar Batu 03-01, Kolam Ayer Ind. Park Singapore 1334 Tel.: 65-748-1835 Tlx: 34 929 Fax: 65-743-3065 South Africa: KOPP ELECTRONICS LIMITED P.O. Box 3853

2128 Rivonia

Tel.: 011-444-2333 Fax: 011-444-1706 South Korea: YONG JUN ELECTRONIC CO. #201, Sungwook Bldg. 1460-16, Seocho-Dong Seocho-Ku Seoul, Korea Tel.: 25-231-8002 Fax: 25-231-803 Taiwan, R.O.C.: SOLOMON TECHNOLOGY CORP. 7th Floor No. 2 Lane 47, Sec. 3 Nan Kang Road Taipei Tel.: 886-2788-8989 Fax: 886-288-8275 Thailand: MICROTRONICS THAI LTD. 50/68 T.T. Court Cheng Wattana Road Amphur Pak-Kreed Nonthaburi 11120 Tel.: 66-2584-5807, Ext. 102 Fax: 66-2583-3775 USA: THE INTER-TECHNICAL GROUP, INC. WIMA DIVISION

175 Clearbrook Road

P.O. Box 535 Elmsford, NY 10523-0535 Tel.: 914-347-2474 Fax: 914-347-7230 TAW ELECTRONICS, INC. 4215, W. Burbank, Blvd. Burbank, CA, 91505 Tel.: 818-846-3911 Fax: 818-846-1194 Venezuela: MAGNETICA, S.A. Apartado 78117 Caracas 1074 A Tel.: 58-2241-7509 Fax: 58-2241-5542 WIMA Corporation Capacitor Representatives (Tables 1 and 2 in Applications Section) PRECISION ANALOG FRONT ENDS TC500 TC500A TC510 TC514