Analog Devices Inc./Maxim Integrated ICL7614BCSA

Overview

ICL7614BCSA from Maxim Integrated is a single-channel, externally compensated CMOS operational amplifier optimized for ultra-low input bias current (1 pA typical), programmable quiescent current (10 µA/100 µA/1 mA), and wide supply range (±1 V to ±8 V or 2 V to 16 V single supply). It features rail-to-rail output swing within millivolts of supply rails and is designed for precision low-leakage applications including pH meters, photodiode amplifiers, and long-time-constant integrators.

For engineers reviewing the ICL7614BCSA datasheet, ICL7614BCSA pinout, ICL7614BCSA application, or ICL7614BCSA equivalent, key selection criteria include confirmed 1 pA input bias current at +25°C, 8-pin SOIC package with exposed metal tab (SA code), 0°C to +70°C temperature grade (C suffix), and external compensation requirement via 39 pF capacitor between COMP and OUT pins.

Technical Context

The ICL7614BCSA implements a monolithic CMOS input stage enabling 10¹² Ω input impedance and 0.01 pA/√Hz input noise current. Its externally compensated architecture uses a dedicated COMP pin (Pin 6) tied to OUT (Pin 1) via 39 pF for unity-gain stability - reducing capacitance increases bandwidth but risks instability. Quiescent current is set by voltage applied to IOSET (Pin 5): V+ selects 10 µA, mid-supply selects 100 µA, and V− selects 1 mA.

Output stage operates in Class A for high linearity with 1 MΩ load (±4.9 V swing at ±5 V supplies), transitioning to Class AB under heavier loads. Common-mode input range is −0.4 V to +0.6 V relative to supplies, and offset nulling is supported via external 25 kΩ potentiometer across OFFSET pins (Pins 2 & 3) referenced to V+ (Pin 4).

Key Specifications

Pinout & Package

ICL7614BCSA is housed in an 8-pin Small Outline Integrated Circuit (SOIC) package with exposed metal thermal pad (SA code), compliant with JEDEC MS-012AC, 1.75 mm body width, and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1050CS8#PBF and TLC27L7CDR, the ICL7614BCSA offers unique programmable quiescent current and external compensation for bandwidth customization, while maintaining industry-standard SOIC-8 footprint and explicit offset null capability - making it optimal for precision, low-power, and layout-controlled analog signal chains.

Availability

ICL7614BCSA is available at Aetrix Electronics and suitable for battery-powered instruments, low-leakage amplifiers, and long-time constant integrators requiring stable component supply across industrial and test equipment lifecycles.

Supply support for ICL7614BCSA 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 high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The ICL761X–ICL764X family was engineered specifically for ultra-low-input-current precision signal conditioning in high-impedance sensor interfaces, electrochemical measurement, and energy-efficient portable instrumentation.

FAQ

What is the correct compensation capacitor value for stable unity-gain operation of the ICL7614BCSA?

The ICL7614BCSA requires a 39 pF capacitor connected between Pin 6 (COMP) and Pin 1 (OUT) for guaranteed unity-gain stability. Reducing this value increases bandwidth and slew rate but may induce peaking or oscillation. The ICL7614BCSA datasheet specifies 39 pF as the minimum value ensuring phase margin >45° across temperature and process variations.

Does the ICL7614BCSA support single-supply operation, and what is its common-mode input range in that configuration?

Yes, the ICL7614BCSA operates from a single supply of 2 V to 16 V. In single-supply mode with V− grounded, its common-mode input range is −0.4 V to +0.6 V relative to the supplies - meaning inputs can go 0.4 V below ground and 0.6 V above V+, enabling true rail-to-rail input capability only when V+ ≥ 1 V and V− ≤ −0.4 V. For ground-referenced sensors, level-shifting or dual supplies are recommended.

How is quiescent current programmed on the ICL7614BCSA, and what are the resulting performance trade-offs?

Quiescent current on the ICL7614BCSA is set via voltage applied to Pin 5 (IOSET): tie to V+ for 10 µA, apply mid-supply voltage (e.g., V+/2) for 100 µA, or tie to V− for 1 mA. Increasing IQ raises unity-gain bandwidth (0.044 → 1.4 MHz) and slew rate (0.016 → 1.6 V/µs), but also increases supply current and thermal dissipation - requiring careful PCB thermal design at 1 mA in SOIC-8.

Can the ICL7614BCSA be used without offset nulling, and what is the impact on system accuracy?

Yes, the ICL7614BCSA functions without external offset nulling, but its B-grade maximum input offset voltage is 5 mV at +25°C - translating to up to ±5 mV DC error in unity-gain configurations. For applications requiring <100 µV offset, the two OFFSET pins (Pins 2 & 3) must be used with a 25 kΩ potentiometer referenced to V+ (Pin 4) to trim VOS down to <50 µV, as verified in production test data for ICL7614BCSA units.

What PCB layout practices are essential to preserve the 1 pA input bias current specification of the ICL7614BCSA?

To maintain the ICL7614BCSA's 1 pA input bias current, inputs (Pins 7 & 8) must be guarded with a low-impedance trace held at the same potential - typically ground for inverting amps or output voltage for non-inverting buffers. The guard ring must surround both input traces and connect to the guard driver. Additionally, the board must be thoroughly cleaned post-soldering and conformally coated if operating in >60% RH environments to prevent surface leakage paths that degrade effective input resistance.