Application of the GXSC DAC as a Replacement for the LTC2642 in High-Resolution Offset and Gain Adjustment

In precision measurement and control, data acquisition, automated testing, and analog signal conditioning systems, signal offset errors and gain deviations are key factors that limit the measurement accuracy of the entire system and the stability of closed-loop control. In precision analog signal chains, zero-point offset and gain errors are common during long-term operation and under varying temperature conditions. This requires a digital-to-analog converter (DAC) chip with high resolution, ultra-low differential nonlinearity, and low-drift stable output. The GXSC 16-bit DAC is an ideal solution for this application.

The GXSC DAC is a series of low-power, 16-bit, unbuffered voltage-output digital-to-analog converters powered by a single 2.7V to 5.5V supply, ensuring monotonicity across the entire temperature range. The chip delivers 16-bit performance (±1 LSB INL and ±1 LSB DNL) throughout the temperature range. The unbuffered DAC output results in a supply current as low as 120 µA, while maintaining an offset error as low as ±1 LSB.

The GXSC DAC features a reference input range of 2 V to VDD, with a VOUT range from 0 V to VREF. For bipolar operation, it includes matched voltage-divider resistors that can be used with an external precision operational amplifier to generate a ±VREF output swing at the RFB pin. A simple SPI/MICROWIRE-compatible 3-wire serial interface is provided, supporting clock rates up to 50 MHz, and can interface directly with optocouplers for applications requiring isolation.

GXSC DAC Features:

Pin-to-pin replacement for the LTC2642

Maximum 16-bit INL error: +1 LSB over the entire temperature range

Low supply current: 120 μA, guaranteed to be monotonically decreasing over the entire temperature range

2.7 V to 5.5 V single-supply operation

1μs settling time to 16 bits

Unbuffered voltage output capable of directly driving a 60kΩ load

50MHz SPITM/QSPITM/MICROWIRE™-compatible serial interface

Power-on reset clears the DAC output to zero or mid-scale

3mm x 3mm 8-pin DFN package