Analog Devices Inc./Maxim Integrated ICL7611ACPA

Overview

ICL7611ACPA 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 operation (or 2–16 V single supply), 1 pA typical input bias current at +25°C, and rail-to-rail output swing within millivolts of supply rails - ideal for pH meter front-ends and picoammeter circuits.

For engineers reviewing the ICL7611ACPA datasheet, ICL7611ACPA pinout, ICL7611ACPA application, or ICL7611ACPA equivalent, this page delivers verified specifications, package mapping, functional alternatives, and design-critical context for low-leakage analog signal conditioning in battery-powered instrumentation and high-impedance sensor interfaces.

Technical Context

The ICL7611ACPA implements a monolithic CMOS architecture enabling 1 pA input bias current and 10¹² Ω input resistance, supporting stable DC gain in ultra-high-source-impedance applications such as photodiode transimpedance amplifiers. Its programmable IQ pin directly configures quiescent current, which linearly scales unity-gain bandwidth (0.044–1.4 MHz) and slew rate (0.016–1.6 V/µs).

Internally compensated for unity-gain stability, it features offset-null terminals for precision DC adjustment and operates across –0°C to +70°C. Input common-mode range extends to within 0.4 V of rails at IQ = 10 μA, while output swing reaches ±4.8 V on ±5 V supplies into 1 MΩ load.

Key Specifications

Pinout & Package

ICL7611ACPA uses an 8-pin plastic DIP (Dual In-line Package) with industry-standard pinout and pin 7 internally connected to case ground. The device includes dedicated OFFSET null terminals and an IQ programming pin for quiescent current selection.

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 TLC27L1CP, the ICL7611ACPA uniquely combines programmable quiescent current, dual-supply operation, offset nulling, and 1 pA bias in an industry-standard 8-pin DIP - making it optimal for mixed-rail, high-precision, and field-calibratable analog front-ends.

Availability

ICL7611ACPA is available at Aetrix Electronics and suitable for pH meters, picoammeters, low-leakage amplifiers, and long-time-constant integrators requiring stable component supply across industrial and medical OEM programs.

Supply support for ICL7611ACPA 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 demanding industrial, medical, and communications applications.

The ICL761X family was engineered specifically for ultra-low-input-current signal conditioning - targeting electrochemical sensors, photodetection, and precision metrology where femtoampere-level leakage must be avoided.

FAQ

What is the maximum supply voltage rating for the ICL7611ACPA?

The ICL7611ACPA has an absolute maximum total supply voltage (V+ to V−) of +18 V. It operates reliably across ±1 V to ±8 V dual supplies or 2–16 V single supplies. Exceeding +18 V risks permanent damage, and operation near limits requires thermal derating per the 250 mW dissipation rating for its 8-pin plastic DIP package.

How does the IOSET pin configure quiescent current in the ICL7611ACPA?

The IOSET pin (Pin 8) of the ICL7611ACPA selects quiescent current: connect to V+ for 10 μA, bias between V− + 0.8 V and V+ − 0.8 V for 100 μA, or connect to V− for 1 mA. This direct voltage-level control adjusts bandwidth, slew rate, and output drive while preserving rail-to-rail output swing and ultra-low input bias current.

Does the ICL7611ACPA support offset nulling, and how is it implemented?

Yes, the ICL7611ACPA supports offset nulling via Pins 3 (OFFSET) and 8 (IOSET). A 25 kΩ potentiometer is connected between these pins, with its wiper tied to V+. Nulling range is sufficient for all VOS grades (2–15 mV) at IQ = 100 μA or 1 mA, though limited at IQ = 10 μA for higher-VOS variants.

What is the input common-mode voltage range of the ICL7611ACPA at 10 μA quiescent current?

At IQ = 10 μA, the ICL7611ACPA's input common-mode voltage range is –4.0 V to +4.4 V on ±5 V supplies - i.e., within 0.4 V of V− and 0.6 V of V+. This extended range supports operation with inputs near supply rails, critical for single-supply sensor interfaces where reference voltages sit close to ground or VCC.

Is the ICL7611ACPA internally compensated, and what are the implications for stability?

Yes, the ICL7611ACPA is internally compensated for unity-gain stability - no external capacitor required. This guarantees phase margin >45° and monotonic step response across all IQ settings and load conditions up to 100 pF. Unlike the externally compensated ICL7614, it eliminates layout sensitivity and simplifies design for general-purpose precision amplification.