MAX1677

The MAX1677 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that contains two separate switching-regulator circuits. The first circuit is configured for a +3.3V main output and +20V LCD bias voltage. It accepts inputs from +0.7V to +3.3V. The main +3.3V output supplies up to 350mA from a 2-cell input, or 140mA from a 1-cell input, while the LCD bias output supplies up to 12mA at +20V.

The second circuit converts a +0.7V to +3.3V battery voltage to a +3.3V main output and a -20V LCD bias voltage. The main +3.3V output supplies up to 350mA from a 2-cell input, or 140mA from a 1-cell input, while the LCD bias output supplies 10mA at -20V.

The MAX1677 features internal N-channel MOSFET switches, a synchronous rectifier, low-battery comparator,and selectable PFM/PWM mode. The MAX1677 EV kit provides low quiescent current and high efficiency-up to 95% for maximum battery life. Operation at 300kHz allows the use of tiny surface-mount inductors.