Analog Devices Inc./Maxim Integrated ICL7614DCPA

Overview

ICL7614DCPA from Maxim Integrated is a single, externally compensated, ultra-low-input-bias-current CMOS operational amplifier in an 8-pin plastic DIP package. It delivers 1pA typical input bias current, ±1V to ±8V dual-supply operation (or 2V–16V single supply), and programmable quiescent current (10µA/100µA/1mA) - enabling precision low-leakage amplification in pH meters, photodiode front-ends, and long-time-constant integrators.

For engineers reviewing the ICL7614DCPA datasheet, ICL7614DCPA pinout, ICL7614DCPA application, or ICL7614DCPA equivalent, this page provides verified pin assignments, real-world use cases for high-impedance signal conditioning, quiescent current selection guidance, and two validated alternative op amps with documented performance trade-offs.

Technical Context

The ICL7614DCPA uses monolithic CMOS architecture to achieve 1pA input bias current and 10¹²Ω input resistance, making it suitable for sensor interfaces with source impedances >100MΩ. Its external compensation (via 39pF capacitor between COMP and OUT pins) enables bandwidth optimization - unity-gain bandwidth scales from 44kHz at 10µA IQ to 1.4MHz at 1mA IQ.

It supports three quiescent current modes selected by the IOSET pin voltage: 10µA (low-power, low-noise), 100µA (balanced speed/power), or 1mA (high slew rate: 1.6V/µs). Output swing reaches within millivolts of rails under light loads (1MΩ), and common-mode input range extends to V− −0.4V and V+ +0.6V at 10µA IQ.

Key Specifications

Pinout & Package

ICL7614DCPA is housed in an 8-pin plastic DIP (Dual In-line Package) with industry-standard pinout and pin 7 internally connected to case (ground reference). The device requires external compensation via a capacitor between pins 6 (COMP) and 8 (OUT).

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 TLC27L7CP, the ICL7614DCPA uniquely combines programmable quiescent current, external compensation for bandwidth tuning, and guaranteed 1pA bias across its full temperature range - making it optimal for battery-constrained, high-impedance, multi-range analog front-ends.

Availability

ICL7614DCPA is available at Aetrix Electronics and suitable for pH meter design, photodiode signal conditioning, and long-time-constant integrator circuits requiring stable component supply across industrial and medical instrumentation programs.

Supply support for ICL7614DCPA 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-high-impedance, low-power signal conditioning - targeting electrochemical sensors, photodetectors, and precision integrators where input leakage dominates error budgets.

FAQ

What is the function of the IOSET pin on the ICL7614DCPA?

The IOSET pin (pin 5) on the ICL7614DCPA selects quiescent current: connecting it to V+ sets IQ = 10µA, to mid-supply (~V+/2) sets IQ = 100µA, and to V− sets IQ = 1mA. This directly controls unity-gain bandwidth (44kHz to 1.4MHz), slew rate (0.016V/µs to 1.6V/µs), and output drive capability - allowing dynamic optimization for each application's speed/power trade-off. The ICL7614DCPA must be configured before operation to avoid undefined behavior.

Why does the ICL7614DCPA require external compensation while other ICL761X parts do not?

The ICL7614DCPA uses external compensation (via a capacitor between COMP pin 6 and OUT pin 8) to provide design flexibility - users can adjust the 39pF default value to increase bandwidth or improve phase margin for specific closed-loop gains. In contrast, ICL7611/ICL7612/ICL7616 are internally compensated for unity-gain stability. This makes the ICL7614DCPA ideal for non-unity-gain configurations (e.g., G = 5–10) where tailored frequency response is needed without sacrificing stability.

Can the ICL7614DCPA operate from a single 3.3V supply?

Yes, the ICL7614DCPA supports single-supply operation from 2V to 16V. At 3.3V, it delivers usable output swing (typically ±1.4V with 1MΩ load) and maintains 1pA input bias current. However, common-mode input range is limited to approximately 0.2V above V− and 0.6V below V+, so input signals must stay within ~0.2V to ~2.7V. For rail-to-rail input capability at 3.3V, consider the ICL7612 variant instead - the ICL7614DCPA is optimized for ultra-low bias, not extended CMVR.

How is input offset voltage nulled on the ICL7614DCPA?

Input offset voltage on the ICL7614DCPA is nulled using pins 1 (OFFSET) and the adjacent OFFSET terminal (not shown in DIP pinout but present as dedicated pins in TO-99; in DIP, pin 1 and pin 8 are used with external circuitry per datasheet Figure 1). A 25kΩ potentiometer is connected between these OFFSET pins, with its wiper tied to V+. Nulling range is sufficient for all VOS grades (2–20mV) at IQ = 100µA or 1mA, but may be insufficient at IQ = 10µA with higher-VOS variants. Always verify nulling margin in final layout.

What PCB layout practices are essential to achieve the specified 1pA input bias current for the ICL7614DCPA?

To achieve the ICL7614DCPA's 1pA input bias current, guard rings must surround both input traces (pins 2 and 3), held at the same potential as the inputs - typically ground for inverting amps or output voltage for unity-gain buffers. Use clean, conformal-coated boards in humid environments; avoid flux residues near inputs; and route high-impedance nodes away from noisy digital lines. The ICL7614DCPA's performance degrades rapidly if surface leakage paths dominate - proper guarding reduces effective input leakage by >100× versus unguarded layouts.