ICL7135CPI+

ADCs/DACs - Special Purpose Overview

The ICL7135CPI+ is a monolithic 4½-digit analog-to-digital converter featuring dual-slope conversion and multiplexed BCD outputs. It provides ±20,000 count resolution with guaranteed ±1 count accuracy over the operating temperature range. The device operates on single or split supplies, typically +5V and -5V, consuming a maximum of 6mA total supply current. Key electrical parameters include a full-scale input capability of 2.0000V, an auto-zero accuracy better than 10µV, zero drift of 0.5µV/°C, and a maximum input bias current of 10pA. It utilizes a 28-pin Plastic DIP package.

ADCs/DACs - Special Purpose Feature Summary

• Dual-slope integration architecture providing high precision and noise immunity
• Multiplexed BCD outputs compatible with TTL logic for direct display interfacing
• True differential inputs with high impedance CMOS buffer
• Status outputs including BUSY, STROBE, OVER-RANGE, and UNDERRANGE

ADCs/DACs - Special Purpose Applications

• Digital Voltmeters (DVMs)
• Panel Meters
• Microprocessor-based data acquisition systems
• Precision measurement instruments requiring ratiometric operation

ADCs/DACs - Special Purpose Procurement Notes

Verify the suffix 'CPI+' indicates a lead-free, RoHS-compliant version in the 28-lead plastic DIP package. Confirm the manufacturer source, as Analog Devices acquired Maxim Integrated. Ensure the specific revision level matches the design requirements for absolute maximum ratings and electrical characteristics.

ADCs/DACs - Special Purpose Selection Notes

Select external components carefully to optimize performance. Use polypropylene or Teflon integrating capacitors to minimize dielectric absorption errors. Choose a reference capacitor with low leakage to maintain scale factor stability. Set the clock frequency to reject power line interference, such as 120kHz for 60Hz rejection.

ADCs/DACs - Special Purpose Part Context

The ICL7135 is part of the ICL713x family of integrating ADCs. It serves as a higher-resolution alternative to the 3½-digit ICL7136 and offers multiplexed outputs unlike the parallel output ICL7129. It is designed for applications requiring direct interface to LCD or LED displays without complex external decoding logic.

ADCs/DACs - Special Purpose Replacement Considerations

The ICL7135CPI+ is functionally equivalent to the older ICL7135CPI. Verify pinout compatibility if replacing non-Maxim variants. No direct drop-in replacement with different pin counts is available within this specific family.