TC835CKW

ADCs/DACs - Special Purpose Overview

The TC835CKW is a low-power, 4-1/2 digit (0.005% resolution) BCD analog-to-digital converter manufactured by Microchip Technology. Characterized for 200 kHz clock rate operation, it delivers five conversions per second, which is nearly twice the speed of the ICL7135 or TC7135. The device operates on a single +5V supply when paired with an external charge pump like the TC7660, or standard ±5V supplies. It features multiplexed BCD data outputs and control signals including BUSY, STROBE, RUN/HOLD, OVERRANGE, and UNDERRANGE, facilitating direct interfacing with microprocessors and UARTs without requiring external sample-and-hold circuits.

ADCs/DACs - Special Purpose Feature Summary

• Dual-slope integrating architecture with system zero and integrator output zero phases for enhanced accuracy
• Multiplexed BCD data output compatible with LCD and LED display decoder/drivers
• Input sensitivity of 100 µV with typical nonlinearity error of 0.5 counts
• Supports single +5V operation with external voltage inverter or dual ±5V supplies

ADCs/DACs - Special Purpose Applications

• Personal computer data acquisition systems
• Microprocessor-based scales and intelligent panel meters
• Process controls and measurement systems
• HP-IL bus instrumentation

ADCs/DACs - Special Purpose Procurement Notes

Verify the package type matches the required form factor, as the TC835 is available in 28-pin PDIP, 44-pin MQFP, and 64-pin MQFP. The CKW suffix specifically denotes the 44-pin MQFP package. Confirm that the operating temperature range meets the application requirements, as this variant is characterized for commercial temperatures from 0°C to +70°C. Ensure power supply rails align with the specified absolute maximum ratings to prevent device damage.

ADCs/DACs - Special Purpose Selection Notes

Select the TC835 for applications requiring high-resolution DC measurements with inherent noise immunity due to its integrating nature. It is suitable for designs needing direct BCD output to simplify display logic. Consider the 200 kHz clock frequency limit; higher frequencies may introduce nonlinearity unless compensated. Ensure the external reference voltage stability is sufficient, as it directly impacts overall absolute accuracy. Verify that the analog input common-mode range accommodates the signal source voltages relative to the supply rails.

ADCs/DACs - Special Purpose Part Context

The TC835 serves as a pin-compatible upgrade to the TC7135 and ICL7135, offering improved conversion speed while maintaining similar interface characteristics. Unlike the ICL7135, it does not require external diode resistor rollover error compensation circuits. The device integrates auto-zero and offset compensation internally, reducing calibration steps. It is part of Microchip's legacy precision ADC portfolio, designed for cost-effective, high-resolution data acquisition in industrial and consumer electronics.

ADCs/DACs - Special Purpose Replacement Considerations

The TC835 is a direct pin-compatible replacement for the TC7135 and ICL7135. Designers upgrading from these parts should verify that the faster conversion rate does not impact existing timing constraints. No external rollover compensation components are needed, allowing for potential circuit simplification. Ensure that the new design accounts for the specific power supply configurations supported by the TC835.