1 Features

1• High Gain Bandwidth Product: 1.6 GHz

• High Bandwidth 275 MHz (G = 10)

• Slew Rate 700 V/μs (G = 10, 1-V Step)

• Low-Input Offset Voltage: ±250 μV

• Low-Input Bias Current: 2 pA

• Low-Input Voltage Noise: 4.8 nV/√Hz

• High-Output Current: 70 mA

• Fast Overdrive Recovery

2 Applications

• Wideband Photodiode Amplifiers

• Wafer Scanning Equipment

• ADC Input Amplifiers

• Test and Measurement Front Ends

• High Gain Precision Amplifiers

• Optical Time Domain Reflectometry (OTDR)

3 Description

The OPA657 device combines a high gain-bandwidth,

low-distortion, voltage-feedback operational amplifier

with a low voltage noise JFET-input stage to offer a

very high dynamic range amplifier for high-precision

analog-to-digital converter (ADC) driving or wideband

transimpedance applications. Photodiode applications

achieve improved noise and bandwidth using this

decompensated, high gain-bandwidth amplifier.

Very low level signals can be significantly amplified in

a single OPA657 gain stage with exceptional

bandwidth and accuracy. The very low input bias

current and capacitance supports this performance

even for relatively high source impedance.

Broadband photodetector applications benefit from

the low voltage noise JFET inputs for the OPA657.

The JFET input contributes virtually no current noise,

which makes the device ideal for high-gain

photodiode applications.