LTC1428-50

The LTC1428-50 is a micropower 8-bit current sink output D/A converter (DAC) with an output range of 0µA to 50µA. In 3.3V or 5V systems, the DAC I_OUT pin can be biased from 2V to 10V. Supply current is only 130µA. Shutdown mode drops the supply current to 0.2µA.

The LTC1428-50 communicates with external circuitry by using one of three interface modes: standard 3-wire serial mode or one of two pulse modes. Upon power-up, the internal counter resets to 10000000B, the DAC output assumes midrange and the chip configures to 3-wire or pulse mode depending on the CS signal level.

In 3-wire mode, the system MPU can serially transfer 8-bit data to and from the LTC1428-50. In pulse mode, the upper six bits of the DAC output program for increment-only (1-wire interface) or increment/decrement (2-wire interface) operation depending on the D_IN signal level. In increment-only mode, the counter rolls over and sets the DAC to zero if the counter increases beyond full scale. In increment/decrement mode, the counter stops incrementing at full scale, stops decrementing at zero scale and does not roll over.

LTC1428-50 is available in an 8-pin SO package.

Applications

• LCD Contrast Control
• Backlight Brightness Control
• Power Supply Voltage Adjustment
• Battery Charger Voltage/Current Adjustment
• GaAs FET Bias Adjustment
• Trimmer Pot Elimination