LM13700

The LM13700 is an integrated circuit consisting of two current controlled operational transconductance amplifiers (OTA), each having differential inputs and a push-pull output.[1] The LM13700 is like a standard op-amp: each has a pair of differential inputs and a single output, but an OTA is voltage in and current out rather than voltage in and voltage out; and OTAs are programmable via the IABC pin. Linearizing diodes at the input reduce distortion and allow increased input levels. The darlington output buffers provided are specifically designed to complement the wide dynamic range of the OTA. This chip is very useful in audio electronics especially in analog synthesizer circuits like voltage controlled oscillators, voltage controlled filters, and voltage controlled amplifiers. The darlington output buffers on the LM13700 are different from those on the LM13600 in that their bias currents (and hence their output DC levels) are independent of IABC pin. This may result in performance superior to that of the LM13600 in audio applications.

Schematic symbol for the OTA — Like the standard operational amplifier, it has both inverting (−) and noninverting (+) inputs; power supply lines (V+ and V−); and a single output. Unlike the traditional op-amp, it has two additional biasing inputs, I_abc and I_bias