Wideband transconductance operational amplifier and buffer circuit composed of OPA660

The OPA660 is a general-purpose integrated circuit designed for broadband systems, including high-performance video, RF, and IF circuits. The OPA660 contains a broadband bipolar voltage-controlled current source and a voltage buffer amplifier. The voltage-controlled current source or transconductance operational amplifier (OTA) can be considered an "ideal triode". Like a triode, the OPA660 has three poles: a high-impedance input (base), a low-impedance input/output (emitter), and a current output (collector). The OTA is self-biased and bipolar, and the output current is zero when the differential input voltage is zero. The alternating current (AC) input is centered at zero, producing an output bipolar current centered at zero. The transconductance of the OTA can be adjusted with external resistors, allowing a trade-off between bandwidth, quiescent current, and gain to determine the optimal design. The open-loop buffer amplifier provides 850MHz bandwidth and a 3000V/μs conversion rate. Like the basic component module, OPA660 has simple AGC amplification, driving LED as optical fiber emitting light, fast pulse integrator, fast control loop amplifier, capacitive sensor and control amplifier of effective filter. OPA660 adopts 8-pin plastic DIP and SO-8 surface package, which can be used for basic line recovery circuit, video/broadcasting equipment, communication equipment, high-speed data acquisition, broadband LED driver, AGC multiplier, nanosecond pulse integrator, control loop amplifier, 400MHz differential input amplifier, etc. The pin arrangement of OPA660 and its equivalent circuit are shown in the figure. In the figure, Io=20mA, G=1 R3/2Rs=3.