Analog Devices Inc./Maxim Integrated ICL7611DESA

Overview

ICL7611DESA from Maxim Integrated is a single, 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 2–16 V single-supply operation, 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 photodiode amplifiers requiring femtoamp-level leakage control.

For engineers reviewing the ICL7611DESA datasheet, ICL7611DESA pinout, ICL7611DESA application, or ICL7611DESA equivalent, this page delivers verified electrical specs, temperature-rated SOIC-8 package details, offset-nulling implementation guidance, and validated alternatives for low-leakage analog signal conditioning in battery-powered and high-impedance sensor systems.

Technical Context

The ICL7611DESA implements monolithic CMOS architecture with programmable IQ control via the IOSET pin, enabling trade-offs between bandwidth (0.044–1.4 MHz), slew rate (0.016–1.6 V/µs), and power consumption across three discrete quiescent current modes. Its input stage features 10¹² Ω input impedance and 0.01 pA/√Hz input noise current - optimized for transimpedance amplification where source impedance exceeds 1 GΩ.

It supports internal unity-gain compensation (no external capacitor required), operates over –40°C to +85°C, and maintains guaranteed 15 mV max input offset voltage (D-grade) and 4 nA max input bias current at +125°C - critical for long-time-constant integrators and picoammeter designs where drift and leakage dominate error budgets.

Key Specifications

Pinout & Package

ICL7611DESA is housed in an 8-pin Small Outline Integrated Circuit (SOIC) package (SA code), surface-mount compatible, with 1.27 mm pitch and JEDEC MS-012AC footprint. Thermal resistance θ_JA = 160°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1050CS8#PBF and TLC27L1CDR, the ICL7611DESA uniquely balances ultra-low bias current stability over –40°C to +85°C, offset trim capability, and programmable IQ - making it the only choice for production-grade picoammeters and field-deployed pH meters requiring both precision and thermal robustness.

Availability

ICL7611DESA is available at Aetrix Electronics and suitable for pH meter front-ends, photodiode transimpedance amplifiers, picoammeter core circuits, and low-droop sample/hold applications requiring stable component supply across industrial and medical product lifecycles.

Supply support for ICL7611DESA 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 automotive applications.

The ICL761X family was engineered specifically for ultra-high-impedance, low-power sensor signal conditioning - targeting applications where input leakage, offset drift, and supply flexibility outweigh raw speed requirements.

FAQ

What is the maximum operating supply voltage for the ICL7611DESA?

The ICL7611DESA supports a total supply voltage (V+ to V–) of up to +18 V. In dual-supply mode, this translates to ±8 V; in single-supply mode, it operates from 2 V to 16 V. Exceeding these limits risks permanent damage per Absolute Maximum Ratings. The ICL7611DESA datasheet specifies derating curves for power dissipation above +25°C ambient, with 250 mW maximum at 25°C for the SOIC-8 package.

How do I configure the quiescent current (IQ) on the ICL7611DESA?

The ICL7611DESA uses its IOSET pin (Pin 5) to select one of three quiescent current modes: connect IOSET to V+ for 10 μA, to a mid-rail voltage between V– + 0.8 V and V+ – 0.8 V for 100 μA, or to V– for 1 mA. This selection directly scales unity-gain bandwidth (0.044–1.4 MHz) and slew rate (0.016–1.6 V/µs). The ICL7611DESA's IOSET pin does not require pull-up/down resistors - direct connection suffices.

Does the ICL7611DESA require external frequency compensation?

No, the ICL7611DESA is internally compensated for stable unity-gain operation and requires no external capacitor. This distinguishes it from the ICL7614 variant (which uses external compensation between COMP and OUT pins). The internal compensation ensures phase margin >60° across all IQ settings and supply voltages, eliminating layout sensitivity and reducing bill-of-materials cost in the ICL7611DESA design.

Can the ICL7611DESA drive capacitive loads?

The ICL7611DESA can drive moderate capacitive loads (≤100 pF) directly with stable step response. For larger loads (e.g., >500 pF hold capacitors), a series isolation resistor (10–100 Ω) between output and load is recommended to maintain phase margin. The ICL7611DESA's CMOS output stage provides ≥1 mA sink/source capability at 1 mA IQ, but capacitive loading increases settling time and may induce overshoot - verified in the "Voltage Follower Large Signal Pulse Response" plots of the ICL7611DESA datasheet.

What is the purpose of the OFFSET pins (1 and 8) on the ICL7611DESA?

Pins 1 (OFFSET –) and 8 (OFFSET +) on the ICL7611DESA form a dedicated offset null network: a 25 kΩ potentiometer is connected between them, with its wiper tied to V+. Adjusting the potentiometer injects opposing current to cancel input offset voltage. This is especially valuable for the D-grade ICL7611DESA (15 mV max V_OS) when operating at 10 μA IQ, where factory trimming alone may not meet tight DC accuracy targets in production systems.