Micropower Dual 6-Bit PWM DAC

The LTC1426 is a dual micropower 6-bit PWM DAC featuring versatile PWM outputs and a flexible pushbutton compatible digital interface. The DAC outputs provide a PWM signal that swings from 0V to VREF, allowing the full-scale output to be varied by adjusting the voltage at VREF. The PWM output frequency is typically 5kHz, easing output filtering requirements. VCC supply current is typically 50µA and drops to 0.2µA in shutdown.

The LTC1426 can be controlled using one of two interface modes: pushbutton and pulse. The LTC1426 automatically configures itself into the appropriate mode at start-up by monitoring the state of the CLK pins. In pushbutton mode, the CLK pins can be directly connected to external pushbuttons to control the DAC output. In pulse mode, the CLK pins can be connected to CMOS compatible logic. The DAC outputs initially power up at half scale and the contents of the internal DAC registers are retained in shutdown.

The LTC1426 is available in 8-pin MSOP and SO packages.

Applications

* LCD Contrast and Backlight Brightness Control

* Power Supply Voltage Adjustment

* Battery Charger Voltage and Current Adjustment

* GaAs FET Bias Adjustment

* Trimmer Pot Elimination

* Wide Supply Range: 2.7V ≤ VCC ≤ 5.5V

* Wide Reference Voltage Range: 0V to 5.5V

* Two Interface Modes:

* Pulse Mode (Increment Only)

* Pushbutton Mode (Increment/Decrement)

* Low Supply Current: 50µA

* 0.2µA Supply Current in Shutdown

* Available in 8-Pin MSOP and SO Packages

* DAC Contents Are Retained in Shutdown

* DACs Power-Up at Midrange

* Low Output Impedance: <100Ω

* Output Frequency: 5kHz Typ