FEATURES

2.7-V to 7-V Input Operating Range

Voltage-Mode PWM Control

High-Speed, Source-Sink Output Drive (200 mA)

Internal Oscillator (up to 2 MHz)

Standby Mode

0−100 Controllable Maximum Duty-Cycle

DESCRIPTION

The Si9145 switchmode controller IC is ideally suited for high

efficiency dc/dc converters in low input voltage systems.

Operation is guaranteed down to 2.7 V, with a minimum

start-up voltage of 3.0 V making the Si9145 ideal for use with

NiCd, NMH, and lithium ion battery packs. A mode select pin

allows the output driver polarity to be programmed allowing the

device to function as a step-up or step-down converter.

Features include a precision bandgap reference, a wide

bandwidth error amplifier, a 2-MHz oscillator, an input voltage

monitor with standby mode and a 200-mA output driver.

Supply current in normal operation is typically 1.1 mA and

250 A in standby mode.

The Si9145 implements conventional voltage mode control.

The maximum duty cycle in boost mode can be limited by

voltage on DMAX/SS pin. Frequency can be externally

programmed by selection of ROSC and COSC.

The Si9145 is available in both standard and lead (Pb)-free

16-pin SOIC and TSSOP packages and is specified over the

industrial temperature range (−25 C to 85 C).