TC500/A/510/514 Precision Analog Front Ends with Dual Slope ADC Features: General Description: Precision (up to 17 bits) A/D Converter Front TheTC500/A/510/514 family are precision analog front End ends that implement dual slope A/D converters having a maximum resolution of 17 bits plus sign. As a 3-Pin Control Interface to Microprocessor minimum, each device contains the integrator, zero Flexible: User Can Trade-off Conversion Speed crossing comparator and processor interface logic. The for Resolution TC500 is the base (16-bit max) device and requires Single-Supply Operation (TC510/TC514) both positive and negative power supplies. The 4 Input, Differential Analog MUX (TC514) TC500A is identical to the TC500 with the exception Automatic Input Voltage Polarity Detection that it has improved linearity, allowing it to operate to a Low Power Dissipation: maximum resolution of 17 bits. The TC510 adds an on- board negative power supply converter for single- - (TC500/TC500A): 10 mW supply operation. The TC514 adds both a negative - (TC510/TC514): 18 mW power supply converter and a 4-input differential Wide Analog Input Range: analog multiplexer. - 4.2V (TC500A/TC510) Each device has the same processor control interface Directly Accepts Bipolar and Differential consisting of 3 wires: control inputs (A and B) and zero- Input Signals crossing comparator output (CMPTR). The processor manipulates A, B to sequence the TC5XX through four Applications: phases of conversion: auto-zero, integrate, de- integrate and integrator zero. During the auto-zero Precision Analog Signal Processor phase, offset voltages in the TC5XX are corrected by a Precision Sensor Interface closed loop feedback mechanism. The input voltage is High Accuracy DC Measurements 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 de-integrate 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 maintains 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 remaining in the integrator in preparation for the next conversion. The TC500/A/510/514 offer high resolution (up to 17 bits), superior 50/60 Hz noise rejection, low-power operation, minimum I/O connections, low input bias currents and lower cost compared to other converter technologies having similar conversion speeds. 2008 Microchip Technology Inc. DS21428E-page 1TC500/A/510/514 Package Types 16-Pin PDIP/SOIC/CERDIP 28-Pin PDIP/SOIC C V 1 16 INT DD V 1 28 CAP OUT V 2 15 DGND SS C 2 27 DGND INT C 3 14 CMPTR OUT AZ C 3 26 CAP+ AZ BUF 4 13 B 4 V TC500/ BUF 25 DD TC500A ACOM 5 12 A ACOM 5 24 OSC C V + 6 11 REF IN C 6 23 CMPTR OUT REF C + V 7 10 REF IN C + 7 22 A REF TC514 V V + 8 9 REF REF V B 8 21 REF V + A0 9 20 REF 24-Pin PDIP/SOIC CH4 10 A1 19 V CAP OUT 1 24 11 18 CH1+ CH3 C DGND INT 2 23 12 CH2 17 CH2+ C CAP+ AZ 3 22 CH1 13 16 CH3+ V BUF 14 4 21 DD N/C 15 CH4+ ACOM OSC 5 20 C CMPTR OUT 6 19 REF TC510 C + A 7 18 REF V B REF 8 17 V + V + 9 16 IN REF V N/C 10 15 IN N/C 14 N/C 11 N/C 12 N/C 13 Typical Application Control Logic C A B Converter Sate R INT INT 0 0 Zero Integrator Output C REF 0 1 Auto-Zero C 1 0 Signal Integrate AZ V + V - A1 REF A0 REF 1 1 De-integrate C C C + C - BUF AZ INT REF REF TC500 SW SW Buffer R R Integrator TC500A CH1+ - TC510 CH2+ SW CMPTR 1 I DIF. TC514 CH3+ + CMPTR 2 MUX + CH4+ (TC514) SW - + SW - RI RI Level CMPTR CH1- Shift Output + CH2- CH3- SW SW Z IZ SW CH4- Z SW + Polarity SW - RI RI Detection ACOM SW 1 SW I Analog Phase DGND Switch Decoding Control Logic DC-TO-DC V Signals SS Converter OSC (TC510 & TC514) V - OUT CAP- CAP+ V A B 1.0 F SS C - (TC500 Control Logic 1.0 F OUT TC500A) DS21428E-page 2 2008 Microchip Technology Inc.