TI introduces zero-drift programmable gain amplifiers

The PGA112 and PGA116 offer binary gains of 1, 2, 4, 8, 16, 64, and 128 while the PGA113 and PGA117 have scope gains of 1, 2, 5, 10, 20, 50, 100 and 200. Programmable gains allow for optimum matching of the sensor output to an analog-to-digital converter (ADC) input voltage range. In addition to eliminating the need for matched discrete components, the PGA11x family includes the added benefits of multi-channel MUXs, calibration and digitally controlled gain. The PGA112 and PGA113 have a two-channel MUX, and the PGA116 and PGA117 have a ten-channel MUX. The op amp output stage can be powered by the same power supply as the ADC, which is useful in multi-supply systems to prevent an over-voltage/lockup condition on an ADC input.

The PGA11x family provides internal calibration channels for system-level calibration. Gain switching time is 200 ns and gain settling is 2.55 µs at 0.01 percent. For all of the devices, DC gain error is 0.1 percent (max with G less than or equal to 32) over temperature. All devices use a standard SPI serial interface with daisy-chain capability.

Other highlights include an offset of 100 uV (max) and an offset drift of 1.2 uV/C (max), low noise (12 nV/rtHz typical) and wide bandwidth (10 MHz in G=1). In addition, the devices feature low input on-channel current (5 nA max) and shutdown that can achieve a supply current of less than 4 uA (typical). The PGA11x family is also specified over an extended temperature range of -40C to +125C.

In combination with the PGA11x family, TI provides customers with a state-of-the-art signal chain solution, including ADCs (such as the ADS8318 and ADS7886) and voltage references (such as the REF32xx). The PGA11x family is optimized to work with TI’s MSP430 ultra low-power microcontroller family.