AD847AR vs AD8479BRZ

The AD8479BRZ is a precision, high common-mode voltage difference amplifier designed to measure signals with very high common-mode voltages (up to ±600 V), featuring a fixed gain of 1 and excellent CMRR. The AD847AR is a high-speed, low-power operational amplifier with a 50 MHz gain-bandwidth product and 300 V/µs slew rate, intended for general-purpose signal conditioning and amplification. They serve fundamentally different roles: the AD8479BRZ is a specialized difference amplifier for high-voltage sensing, while the AD847AR is a general-purpose op-amp.

No. The AD847AR is a standard operational amplifier with a maximum supply voltage of ±18 V and no integrated high-voltage input attenuation network. It cannot directly accept common-mode voltages up to ±600 V as the AD8479BRZ can. Substitution would require external precision resistor networks and careful design, and would not match the AD8479BRZ's integrated performance and safety margins.

The AD8479BRZ is offered in an 8-lead SOIC package (R-8 suffix). The AD847AR is available in an 8-lead SOIC (R-8) as well as other package options depending on grade. While both may use an 8-lead SOIC footprint, the pin functions differ: the AD8479BRZ pinout is dedicated to a difference amplifier (e.g., +IN, -IN, REF, OUT, supply pins), whereas the AD847AR follows a standard single op-amp pinout (e.g., +IN, -IN, V+, V-, OUT, NULL). Direct PCB interchange is not possible without redesign.

The AD847AR offers a gain-bandwidth product of 50 MHz and a slew rate of 300 V/µs, making it suitable for high-speed signal processing. The AD8479BRZ, as a precision difference amplifier, has a much lower bandwidth (typically 480 kHz at gain = 1) and is optimized for DC accuracy and high common-mode rejection rather than high-speed operation. The AD847AR is therefore preferred for wideband amplification, while the AD8479BRZ is preferred for precision high-voltage sensing.

The AD8479BRZ operates from dual supplies typically ranging from ±2.5 V to ±18 V (or single supply 5 V to 36 V), with the ability to handle high common-mode voltages independent of its own supply. The AD847AR operates from dual supplies of ±4.5 V to ±18 V (or single supply 9 V to 36 V). Both are compatible with standard ±15 V analog systems, but the AD8479BRZ's input common-mode range extends far beyond its supply rails.

The AD8479BRZ is specifically designed for high-side current sensing where the common-mode voltage can exceed the supply rails, thanks to its ±600 V common-mode input range and high CMRR (typically 90 dB at DC). The AD847AR lacks this capability and would require external level-shifting or isolation circuitry. For precision current sensing in high-voltage rails, the AD8479BRZ is the appropriate choice; the AD847AR is better suited for low-voltage signal amplification after the sensing element.

No. The AD8479BRZ is a precision difference amplifier with low offset voltage (typically ±0.5 mV max for the B grade) and low offset drift, optimized for DC accuracy. The AD847AR is a high-speed op-amp with offset voltage specifications in the range of a few millivolts (e.g., ±5 mV max for the A grade) and is not trimmed for the same level of DC precision. They are not interchangeable where precision DC accuracy is required.

The AD8479BRZ is typically used in high-voltage current sensing, power supply monitoring, motor control, and battery management systems where common-mode voltages exceed the supply rails. The AD847AR is used in general-purpose amplification, active filters, video and RF signal chains, and high-speed data acquisition where wide bandwidth and fast slew rate are needed. Application requirements should guide selection rather than direct substitution.