Analog Devices Inc./Maxim Integrated ICL7616ACPA

Overview

ICL7616ACPA from Maxim Integrated is a single-channel, ultra-low-input-bias-current CMOS operational amplifier with pin-selectable quiescent current (10 µA / 100 µA / 1 mA), ±1 V to ±8 V dual-supply or 2 V to 16 V single-supply operation, and extended common-mode voltage range down to V− (–1.3 V at IQ = 10 µA). It delivers 1 pA typical input bias current, 10¹² Ω input impedance, and rail-to-rail output swing-ideal for pH meter front-ends and photodiode amplification.

For engineers reviewing the ICL7616ACPA datasheet, ICL7616ACPA pinout, ICL7616ACPA application, or ICL7616ACPA equivalent, this page provides verified pin configuration, real-world design meaning of key specs (e.g., VCMR extension enabling true single-supply sensor interfacing), and two validated alternative op amps with documented functional trade-offs in low-leakage signal chains.

Technical Context

The ICL7616ACPA implements a monolithic CMOS input stage with programmable quiescent current via the IOSET pin, directly controlling unity-gain bandwidth (0.044–1.4 MHz) and slew rate (0.016–1.6 V/µs) while preserving rail-swing capability. Its extended common-mode input range includes the negative rail (V−) under IQ = 10 µA or 100 µA, enabling direct connection to grounded sensors without level-shifting.

This architecture supports high-impedance source interfacing (e.g., glass pH electrodes, photodiodes) with <0.01 pA/√Hz input noise current and 100 nV/√Hz voltage noise-critical for sub-picoampere current measurement and long-time-constant integrators where bias current drift dominates error.

Key Specifications

Pinout & Package

ICL7616ACPA uses an 8-pin plastic DIP (Dual In-line Package) with industry-standard pinout matching legacy precision op amps. The package is through-hole mountable, RoHS-compliant, and rated for 0°C to +70°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-bias-current op amp applications.

Compared with LTC1050CN8#PBF and TLC27L2CP, the ICL7616ACPA uniquely combines programmable IQ, 1 pA bias, and extended V−-inclusive common-mode range-making it the only choice for ultra-low-power, single-supply, high-impedance sensor interfaces demanding sub-microvolt stability.

Availability

ICL7616ACPA is available at Aetrix Electronics and suitable for pH meter manufacturing, photodiode-based optical sensing, and low-leakage integrator circuits requiring stable component supply across production lifecycles.

Supply support for ICL7616ACPA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications systems.

The ICL761X family was engineered specifically for ultra-high-impedance, low-power signal conditioning-targeting electrochemical sensors, scientific instrumentation, and battery-operated test equipment where input leakage must be minimized.

FAQ

What is the maximum allowable capacitive load for stable operation of the ICL7616ACPA?

The ICL7616ACPA is not guaranteed stable with capacitive loads exceeding 100 pF. At IQ = 1 mA, avoid resistive loads below 5 kΩ. However, very large capacitive loads (>10 µF) introduce a dominant pole and restore stability-even with low-resistance loads-due to its transconductance-output architecture. Always verify phase margin in final layout using SPICE models from Maxim's website.

Can the ICL7616ACPA operate from a single 3.3 V supply while accepting input signals down to ground?

Yes. With IQ set to 10 µA (IOSET tied to V+), the ICL7616ACPA's extended common-mode range includes V−-so at V− = 0 V (single 3.3 V supply), inputs from 0 V to +0.6 V are fully supported. This enables direct interfacing with grounded sensors like thermistors or pH electrodes without level-shifting circuitry.

How does the IOSET pin configure quiescent current in the ICL7616ACPA?

The IOSET pin selects quiescent current: tie to V+ for 10 µA, leave floating for 100 µA, or tie to V− for 1000 µA. Each setting scales unity-gain bandwidth (0.044/0.48/1.4 MHz) and slew rate (0.016/0.16/1.6 V/µs) linearly while maintaining rail-to-rail output swing and 1 pA input bias current across all modes.

Is input offset nulling supported on the ICL7616ACPA, and what are its limitations?

Yes-via 25 kΩ potentiometer between Pins 1 and 8, wiper to V+. Nulling range is sufficient for all VOS grades (2–20 mV) at IQ = 100 µA or 1 mA, but may be inadequate at IQ = 10 µA with higher-VOS variants (e.g., ICL7616D). For guaranteed nulling across temperature, use IQ ≥ 100 µA or select ICL7616A (2 mV max VOS).

Why does the ICL7616ACPA specify different common-mode voltage ranges depending on quiescent current?

The extended common-mode range (including V−) is only active at IQ = 10 µA or 100 µA. At IQ = 1 mA, the input stage reverts to standard CMVR (–0.4 V to +0.6 V), because the higher bias current enables faster input stage switching but sacrifices rail-inclusive operation. This trade-off ensures optimal performance across both precision and speed use cases.