SBOS859B March 2018 – July 2018 INA1620
The INA1620 integrates a dual, bipolar-input, audio operational amplifier with four high-precision thin-film resistor pairs on the same die. The internal amplifiers and resistor pairs are pinned out to allow for many circuit configurations.
The internal amplifiers of the INA1620 use a unique topology to deliver high output current with extremely low distortion while consuming minimal supply current. A single gain-stage architecture, combining a high-gain transconductance input stage and a unity-gain output stage, allows the INA1620 to achieve an open-loop gain of 136 dB, even with 600-Ω loads.
A separate enable circuit maintains control of the input and output stage when the amplifier is placed into its shutdown mode and limits transients at the amplifier output when transitioning to and from this state. The enable circuit features logic levels referenced to the amplifier ground pin. This configuration simplifies the interface between the amplifier and the ground-referenced GPIO pins of microcontrollers. The addition of a ground pin to the amplifier provides several additional benefits. For example, the compensation capacitor between the input and output stages of the INA1620 is referenced to the ground pin, greatly improving PSRR.