220-MHz CMOS input fully differential amplifier with VICM and VOCM control

The THS4567 device is

a novel fully-differential amplifier (FDA) that includes independent input

common-mode (VICM) and output-common mode (VOCM) control. Standard FDAs only possess

output common-mode control. The THS4567 is a

decompensated amplifier with a minimum stable gain of 10 V/V.

The THS4567 operates as a fully differential transimpedance

amplifier (TIA) and analog-to-digital converter (ADC) driver in a single integrated

stage.

The VICM

loop decouples the reverse bias across the photodiode(PD) from the amplifiers input

and output swing compliance ranges thereby allowing the designer to maximize the PD

reverse bias and minimize the PD capacitance. The VICM loop can be disabled which

then allows the THS4567 to operate as a standard FDA.

The VOCM

loop sets the differential output common-mode voltage and is typically set at the

subsequent ADC stage common-mode reference voltage.