Analog Devices Inc./Maxim Integrated ICL7621DESA+

Overview

ICL7621DESA+ from Maxim Integrated is a dual, low-power CMOS operational amplifier optimized for ultra-low input bias current (1 pA typical), wide supply range (±1V to ±8V or 2V–16V single supply), and programmable quiescent current (10 µA/100 µA/1 mA per amplifier). It features rail-to-rail output swing, 10¹² Ω input impedance, and is used in pH meters, photodiode amplifiers, and long-time-constant integrators where leakage and offset stability are critical.

For engineers reviewing the ICL7621DESA+ datasheet, ICL7621DESA+ pinout, ICL7621DESA+ application, or ICL7621DESA+ equivalent, this page delivers verified electrical specifications, temperature-rated performance (−40°C to +85°C), SOIC-8 package details, and real-world design context for precision analog signal conditioning in battery-powered and high-impedance sensor systems.

Technical Context

The ICL7621DESA+ implements a monolithic CMOS architecture with separate, independently configurable quiescent current paths per amplifier-enabling trade-offs between bandwidth (0.044 MHz at 10 µA, up to 1.4 MHz at 1 mA) and power consumption. Its input stage uses guarded, isolated gate structures to achieve 1 pA bias current and 0.01 pA/√Hz noise current.

It supports internal unity-gain compensation (no external capacitor required), offers offset null capability via dedicated pins, and maintains stable operation across its full common-mode voltage range (e.g., −4.0 V to +4.4 V at IQ = 10 µA with ±5 V supplies), making it suitable for single-supply transducer interfaces without level-shifting circuitry.

Key Specifications

Pinout & Package

ICL7621DESA+ is housed in an 8-pin Small Outline Integrated Circuit (SOIC-8) package, surface-mount compatible, with standard JEDEC MS-012AC dimensions (4.9 mm × 3.9 mm × 1.75 mm). Pin 1 is marked by a notch or dot; the device is RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual precision op amp applications.

Compared with LTC1050CS8#PBF and TLC27L2CDR, the ICL7621DESA+ uniquely balances femtoamp-class input leakage, three-tier IQ scalability, and offset trimming - making it the only choice for battery-operated, high-impedance sensor nodes requiring both nanovolt-level stability and multi-year runtime.

Availability

ICL7621DESA+ is available at Aetrix Electronics and suitable for pH meter manufacturing, photodiode-based environmental sensors, and low-leakage data acquisition systems requiring stable component supply across extended production cycles.

Supply support for ICL7621DESA+ 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) is a semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The ICL76xx family was designed specifically for ultra-high-impedance, low-power analog signal conditioning - targeting electrochemical sensors, scientific instrumentation, and portable test equipment where input leakage and supply flexibility are primary constraints.

FAQ

What is the maximum supply voltage rating for the ICL7621DESA+?

The ICL7621DESA+ has an absolute maximum total supply voltage (V+ to V−) of +18 V. It operates across a wide functional range: ±1 V to ±8 V for dual supplies, or 2 V to 16 V for single-ended supplies. Exceeding +18 V risks permanent damage, and operation above ±8 V or 16 V is not characterized or guaranteed.

Does the ICL7621DESA+ support offset nulling, and how is it implemented?

Yes, the ICL7621DESA+ supports offset nulling via dedicated OFFSET pins (pins 1 and 8 in SOIC-8). A 25 kΩ potentiometer is connected between these pins, with its wiper tied to V+. This configuration provides full VOS trimming range for ICL7621DESA+ variants with VOS ≤ 15 mV at 100 µA or 1 mA IQ settings.

Is the ICL7621DESA+ internally compensated, and does it require external frequency compensation?

Yes, the ICL7621DESA+ is internally compensated for stable unity-gain operation - no external capacitor is required. Unlike the ICL7614 (which is externally compensated), the ICL7621DESA+ integrates compensation circuitry, simplifying layout and eliminating risk of oscillation due to incorrect capacitor selection or placement.

What is the input common-mode voltage range for the ICL7621DESA+ at ±5 V supplies and 10 µA quiescent current?

At ±5 V supplies and 10 µA IQ, the ICL7621DESA+ guarantees a common-mode input voltage range of −4.0 V to +4.4 V. This exceeds the supply rails by margins that enable robust operation with AC-coupled inputs or level-shifted sensor outputs without clipping or phase reversal.

How does quiescent current selection affect bandwidth and slew rate in the ICL7621DESA+?

Quiescent current directly scales key dynamic parameters: at 10 µA IQ, GBW = 0.044 MHz and SR = 0.016 V/µs; at 100 µA, GBW = 0.48 MHz and SR = 0.16 V/µs; at 1 mA, GBW = 1.4 MHz and SR = 1.6 V/µs. This enables precise trade-off tuning for each channel based on signal frequency and power budget.