The OPA656 device combines a very wideband, unity-gain stable, voltage-feedback
operational amplifier with a FET-input stage to offer an ultra high dynamic-range amplifier for
Analog-to-Digital Converter (ADC) buffering and transimpedance applications. Extremely low DC
errors give good precision in optical applications.
The high unity-gain stable bandwidth and JFET input allows exceptional performance in
high-speed, low-noise integrators.
The high input impedance and low bias current provided by the FET input is supported by
the ultra-low 7-nV/√Hz input voltage noise to achieve a very low integrated
noise in wideband photodiode transimpedance applications.
Broad transimpedance bandwidths are achievable given the OPA656 device’s high 230-MHz
gain bandwidth product. As shown below, a –3-dB bandwidth of 1 MHz is provided even for a high 1-MΩ
transimpedance gain from a 47-pF source capacitance.