SC1652 Datasheet | SEMTECH

DESCRIPTION The SC1652 is a high performance inverting DC-DC converter, designed to drive an external power switch to generate programmable negative voltages. In the particularly suitable LCD bias contrast application, efficiency of 87% can be achieved with low cost PNP bipolar transistor drivers. The output voltage can be scaled to -40V by two external resistors. A pulse frequency modulation scheme is employed to maintain high efficiency conversion under wide input voltage ranges. Quiescent current is about 80µA and can be reduced to 0.7µA in shutdown mode. With a switching frequency range of 70k Hz to 160k Hz, small size switching ponents may be used, which is ideal for battery powered portable equipment such as notebook and palmtop puters. Features - 2.4V to 7V input voltage operation - Adjustable output voltage up to -40V - Low quiescent current at 80µA - Pulse frequency modulation maintains high - - - efficiency (max 87%) 70k Hz to 160k Hz switching frequency Power-saving shutdown mode (0.7µA typical) High efficiency with low cost external PNP bipolar transistor APPLICATIONS - Negative LCD Contrast Bias for 1. Notebook & palmtop puters 2. Pen-based data systems 3. Portable data collection terminals 4. Personal digital assistants Negative voltage supplies BLOCK DIAGRAM - ORDERING INFORMATION DEVICE (1) VOUT Adj PACKAGE SO-8 SC1652CS Note: (1) Add suffix ‘TR’ for tape and reel. PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS Parameter Supply Voltage Operating Temperature Range Storage Temperature Range Symbol V+ TA TSTG Maximum 7.0 0 to 70 -65 to 125 Units V °C °C © 1997 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER INVERTING DC-DC CONVERTER January 29, 1998 ELECTRICAL CHARACTERISTICS Unless otherwise specified, TA = 25°C, V+ = 5V Test Conditions Parameter Input Voltage Switch Off Current Shutdown Mode Current VREF Voltage VREF Source Current DLOW “ON Resistance” DHI “ON Resisance” CL Threshold Shutdown Threshold 45 0.8...