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.
关键特性
应用/使用
+0.7V to MAINOUT Battery Input Voltage
Dual Output Voltages
+3.3V Main Output and +20V LCD Bias Output
+3.3V Main Output and -20V LCD Bias Output
All Outputs Also Adjustable with External Resistors
Up to 350mA from 2-Cell Input (Main Output )
Up to 140mA from 1-Cell Input (Main Output)
Up to 12mA Output Current (LCD Bias Output)
Internal N-Channel Switches and Synchronous Rectifier
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