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).