Analog Devices Inc. ADA4637-1ACPZ-R2

Overview

ADA4637-1ACPZ-R2 from Analog Devices is a 30 V, decompensated JFET-input operational amplifier optimized for high-speed precision applications requiring ultra-low noise (6.1 nV/√Hz at 1 kHz), very low input bias current (5 pA max), and high slew rate (170 V/μs). It operates on ±5 V to ±15 V dual supplies and is stable at noise gain ≥5 - used in photodiode amplifiers, DAC output stages, and phase-locked loop filters where dc accuracy and wide bandwidth must coexist.

For engineers reviewing the ADA4637-1ACPZ-R2 datasheet, ADA4637-1ACPZ-R2 pinout, ADA4637-1ACPZ-R2 application, or ADA4637-1ACPZ-R2 equivalent, key selection criteria include its 79 MHz gain bandwidth, 170 V/μs slew rate, 1 μV/°C offset drift, −40°C to +125°C extended temperature rating, and LFCSP package thermal performance - all critical for high-fidelity signal conditioning in instrumentation and medical systems.

Technical Context

The ADA4637-1ACPZ-R2 is a decompensated variant of the ADA4627-1, requiring minimum noise gain of 5 for stability - unlike unity-gain-stable predecessors. Its JFET input stage delivers 5 pA max input bias current and 6.1 nV/√Hz voltage noise at 1 kHz, enabling high-impedance sensor interfacing without significant current-induced error or Johnson noise degradation.

It features 120 dB typical open-loop gain, 116 dB CMRR, and 112 dB PSRR - preserving signal integrity in noisy industrial environments. The device supports rail-compatible input voltage range (−10.5 V to +10.5 V at full temperature range) and delivers ±45 mA output drive into 1 kΩ loads, with 300 ns settling time to 0.01% for 10 V steps at AV = −4.

Key Specifications

Pinout & Package

ADA4637-1ACPZ-R2 is housed in an 8-lead LFCSP_VD (CP-8-13) package with exposed pad, measuring 3 mm × 3 mm × 0.85 mm. Thermal resistance θJA = 77°C/W (with exposed pad soldered to PCB copper plane), enabling high-power-density designs without forced airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed precision op amp applications.

Compared with ADA4627-1ACPZ-R2 and OPA828IDBVR, ADA4637-1ACPZ-R2 uniquely combines 79 MHz bandwidth, 170 V/μs slew, and full −40°C to +125°C qualification - making it the only option for high-gain, high-speed precision signal chains in automotive, aerospace, and energy infrastructure systems.

Availability

ADA4637-1ACPZ-R2 is available at Aetrix Electronics and suitable for photodiode amplification, DAC output buffering, and phase-locked loop filter applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADA4637-1ACPZ-R2 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with R&D and manufacturing operations worldwide.

The ADA4637-1ACPZ-R2 belongs to Analog Devices' high-speed precision op amp family, engineered specifically for applications demanding simultaneous excellence in dc accuracy (low VOS, low drift), ac performance (high GBW, high slew), and ruggedness (extended temperature, high PSRR/CMRR).

FAQ

What is the minimum stable gain for ADA4637-1ACPZ-R2?

The ADA4637-1ACPZ-R2 is decompensated and requires a minimum noise gain of 5 for stable operation. This means it is not unity-gain stable; configurations with AV = 1–4 risk oscillation or peaking. For AV < 5, use the pin-compatible ADA4627-1ACPZ-R2 instead. Stability is verified per Figure 36 and Figure 41 in the Rev. F datasheet, showing 85° phase margin at AV = −4 and AV = +5.

Does ADA4637-1ACPZ-R2 have offset adjust pins?

No - the ADA4637-1ACPZ-R2 in the LFCSP package (ACPZ) does not include offset adjust pins. Only the SOIC_N variants (e.g., ADA4637-1ARZ) feature pins 1 and 5 designated for external nulling. The LFCSP version relies on laser-trimmed thin-film resistors for <200 μV max offset and 1 μV/°C drift, eliminating need for manual adjustment in most precision applications.

What is the recommended power supply bypassing for ADA4637-1ACPZ-R2?

Each supply rail (V+ and V−) of the ADA4637-1ACPZ-R2 must be bypassed within 3 mm using a 0.01 μF X7R ceramic capacitor in parallel with a 1 μF tantalum or aluminum electrolytic capacitor. The ceramic cap must be placed closest to the pins. The exposed pad must be soldered to the V− plane to ensure θJA = 77°C/W and suppress ground bounce during 170 V/μs slewing events.

Can ADA4637-1ACPZ-R2 drive capacitive loads?

Yes - the ADA4637-1ACPZ-R2 can drive moderate capacitive loads (≤100 pF) directly, as confirmed in Figure 24 and Figure 43 of the datasheet. For larger loads (e.g., >200 pF), isolate with a series resistor (20–100 Ω) placed close to the output pin. Avoid using the amplifier in unity-gain follower mode with heavy capacitive loads, as its decompensated topology increases sensitivity to phase margin loss.

Is ADA4637-1ACPZ-R2 suitable for single-supply operation?

No - the ADA4637-1ACPZ-R2 is specified exclusively for dual-supply operation from ±5 V to ±15 V (30 V total). It lacks rail-to-rail input or output capability, and its input voltage range is limited to (V−) + 1.5 V to (V+) − 1.5 V. Single-supply applications require level-shifting circuitry or alternative amplifiers such as the ADA4898-1 or AD8676.