Analog Devices Inc. AD745JRZ-16

Overview

AD745JRZ-16 from Analog Devices is an ultralow-noise, high-speed, FET-input operational amplifier optimized for gains ≥ +5 (or –4). It delivers 20 MHz gain bandwidth, 12.5 V/µs slew rate, 2.9 nV/√Hz input voltage noise at 10 kHz, and 0.5 mV max input offset voltage. It is used in photodiode amplifiers, sonar preamplifiers, and precision accelerometer signal conditioning.

For engineers reviewing the AD745JRZ-16 datasheet, AD745JRZ-16 pinout, AD745JRZ-16 application, or AD745JRZ-16 equivalent, key selection criteria include low-frequency noise performance (0.38 µV p-p, 0.1 Hz to 10 Hz), current noise (6.9 fA/√Hz at 1 kHz), open-loop gain (≥2000 V/mV), and SOIC-16 package compatibility with high-impedance sensor interfaces.

Technical Context

The AD745JRZ-16 employs a BiFET architecture combining JFET input stage for sub-nA bias current (250 pA max) with bipolar-like speed and voltage noise. Its internal compensation is tailored for stable operation at closed-loop gains ≥ +5, enabling higher bandwidth than unity-gain-stable op amps at those configurations.

It features no output phase reversal when common-mode voltage exceeds –10.7 V, supports ±4.8 V to ±18 V dual supply operation, and maintains THD of 0.0002% at 1 kHz with G = –4 into 2 kΩ load - critical for high-fidelity audio and precision instrumentation signal chains.

Key Specifications

Pinout & Package

The AD745JRZ-16 is housed in a 16-lead SOIC (R) package with standard JEDEC outline dimensions (10.0 mm × 7.4 mm × 2.35 mm height), gull-wing leads, and exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OP37GP and AD829ARZ, the AD745JRZ-16 uniquely balances ultralow current noise (6.9 fA/√Hz), sub-microvolt offset (0.5 mV max), and high gain-bandwidth (20 MHz at G ≥ +5), making it the optimal choice for charge-sensitive, high-impedance, wideband sensor interfaces demanding both AC fidelity and DC stability.

Availability

AD745JRZ-16 is available at Aetrix Electronics and suitable for photodiode amplifiers, sonar preamplifiers, and accelerometer signal chains requiring stable component supply across industrial, test & measurement, and aerospace programs.

Supply support for AD745JRZ-16 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.

The AD745JRZ-16 belongs to Analog Devices' precision BiFET op amp product line, designed specifically for applications requiring simultaneous ultralow voltage noise, femtoampere-level input bias current, and high-speed operation in sensor signal conditioning and instrumentation front-ends.

FAQ

What is the maximum input common-mode voltage range for the AD745JRZ-16?

The AD745JRZ-16 supports a common-mode input voltage range of +13.3 V to –10.7 V with ±15 V supplies. It does not exhibit output phase reversal even when the negative common-mode limit is exceeded, allowing safe operation down to –10 V under overrange conditions. This behavior is explicitly guaranteed in the Absolute Maximum Ratings and Electrical Characteristics tables of the REV. D datasheet.

Does the AD745JRZ-16 require external compensation for stability?

No, the AD745JRZ-16 is internally compensated for closed-loop gains of +5 (or –4) and greater. It is not unity-gain stable; attempting G = 1 or G = –1 configurations may cause oscillation. For lower gains, external compensation networks or alternative op amps like the OP37GP must be used. The internal compensation directly enables its 20 MHz bandwidth at G ≥ +5.

What is the typical input bias current of the AD745JRZ-16 at 85°C?

At 85°C, the AD745JRZ-16 exhibits approximately 2.2 nA typical input bias current - derived from the datasheet's "Either Input @ TMAX" specification (2.2 nA max at 70°C) and the documented doubling every 10°C rule. This value assumes proper thermal management; junction temperature rise due to power dissipation further increases bias current, as shown in Figure 9 of the REV. D datasheet.

Can the AD745JRZ-16 drive a 600 Ω load effectively?

Yes, the AD745JRZ-16 delivers ±13 V output swing into 600 Ω loads with <0.01% THD at 1 kHz, as specified in the Output Characteristics table. Its short-circuit current limit of 20–40 mA provides robust protection during fault conditions. For sustained 600 Ω operation, ensure adequate PCB copper area and thermal relief to manage 120 mW+ dissipation per rail.

Is the AD745JRZ-16 suitable for single-supply operation?

The AD745JRZ-16 is specified for dual-supply operation (±4.8 V to ±18 V) and lacks rail-to-rail input or output capability. While it can operate from asymmetric supplies (e.g., +15 V/–5 V), true single-supply use (e.g., 0 V/+15 V) violates its –10.7 V minimum common-mode input requirement and risks phase reversal or saturation. For single-supply sensor interfaces, level-shifting or dedicated rail-to-rail op amps are recommended instead of the AD745JRZ-16.