CN-0273: High Speed FET Input Instrumentation Amplifier
A high-speed FET input instrumentation amplifier circuit offering 35 MHz bandwidth and 55 dB common-mode rejection at 10 MHz using ADA4817-2 and ADA4830-1.
Overview
The CN-0273 reference design describes a high-speed FET input instrumentation amplifier (in-amp) featuring a fixed gain of 5 and a wide 35 MHz bandwidth. The circuit uses the ADA4817-2 dual FastFET op-amp for the input stage to provide high input impedance and a low 2 pA input bias current. The second stage utilizes the ADA4830-1 integrated high-speed difference amplifier, which incorporates laser-trimmed thin film resistors to achieve an excellent common-mode rejection (CMR) of 55 dB at 10 MHz. This integrated approach eliminates the need for expensive external matched resistor networks while reducing board space. The design is optimized for high-frequency signal processing, offering 10 nV/√Hz input voltage noise and low harmonic distortion of -60 dBc at 10 MHz.
Use Cases
- RF signal sensing
- video signal processing
- optical signal sensing
- high speed instrumentation
- wideband differential line receiver
Topics
Referenced Parts
Analog Devices
ADA4830-1 High Speed Difference Amplifier with Input Short-to-Battery Protection
Analog Devices
The difference amplifier at the second stage can be replaced by the AD8274 in lower speed applications.
V/G1
Maxim
• Input differential voltage: ±3.5 V/G1 maximum, where G1
| ADA4817-2 | Analog Devices | ADA4817-2 Low Noise, 1 GHz FastFET Dual Op Amp |
| ADA4830-1 | Analog Devices | ADA4830-1 High Speed Difference Amplifier with Input Short-to-Battery Protection |
| AD8065 | Analog Devices | a rail-to-rail high speed FET input amplifier, such as the AD8065/ AD8066 |
| AD8066 | Analog Devices | a rail-to-rail high speed FET input amplifier, such as the AD8065/ AD8066 |
| AD8274 | Analog Devices | The difference amplifier at the second stage can be replaced by the AD8274 in lower speed applications. |
| V/G1 | Maxim | • Input differential voltage: ±3.5 V/G1 maximum, where G1 |