SC1578
SC1578 is HIGH-EFFICIENCY STEP-DOWN DC-DC CONVERTER manufactured by SEMTECH.
HIGH-EFFICIENCY STEP-DOWN DC-DC CONVERTER
January 29, 1998
TEL:805-498-2111 FAX:805-498-3804 WEB:http://.semtech.
DESCRIPTION
The SC1578 is a high performance step-down DC-DC converter, designed to drive an external P-channel MOSFET to generate programmable output voltages. Two main schemes of pulse-skipping and pulsefrequency modulation are employed to maintain low quiescent current and high conversion efficiency over wide ranges of input voltage and loads. The SC1578 delivers 10m A to 2A of output current with 87%-93% efficiency at VIN=9V, VOUT=5V. A current sense parator with both inverting and non-inverting inputs unmitted is included to provide the crucial function of either current limit protection or constant output current control. When the SC1578 is used in a highside current sensing step-down constant current source, the efficiency is typically greater than 90%. Duty cycle can be adjusted to greater than 90% by connecting a resistor from the DUTY pin to VIN. Quiescent current is about 90µA and can be reduced to 8µA in shutdown mode. With a switching frequency range of 90k Hz to 280k Hz, small size switching ponents may be used, which is ideal for battery powered portable equipment.
Features
- 4V to 24V input voltage operation.
- High efficiency (up to 95%).
- Low quiescent current at 90µA.
- Pulse-skipping and pulse-frequency modulation.
- Inputs-unmitted current sense parator.
- Duty cycle adjustable
- 90k Hz to 280k Hz oscillator frequency
- Power-saving shutdown mode (8µA Typical).
- Push-pull driver output APPLICATIONS
- Notebook 5V/3.3V main power
- Step-down DC-DC converter module.
- Constant current source for battery chargers.
BLOCK DIAGRAM
ORDERING INFORMATION
DEVICE
(1)
PACKAGE SO-8
SC1578CS Note: (1) Add suffix ‘TR’ for tape and reel.
PIN...
