34726 datasheet(13/19 Pages) FREESCALE

Part #	34726

Description	300mA High Efficiency Low Quiescent Current Synchronous Buck Regulator With Z-mode

PDF	19 Pages

Scroll/Zoom	100%

Manufacturer	FREESCALE [Freescale Semiconductor, Inc]

Direct Link	http://www.freescale.com

Logo

13 / 19 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

34726

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

OVER-TEMPERATURE PROTECTION

To limit its operating temperature, the 34726 shuts down if

the junction temperature of the switching MOSFET

surpasses 140°C. If the junction temperature subsequently

drops to 130°C, the 34726 re-starts.

SOFT-START OPERATION

To limit the in-rush current, an internal timer controls the

output voltage ramp after the part is enabled. The start-up

time is internally set to approximately 2.0ms and is

independent of input voltage, output voltage, or load current.

The soft-start sequence also occurs upon recovery from any

fault condition.

UNDER-VOLTAGE LOCK-OUT

The UVLO threshold is set to 2.7V for rising VIN, and to

2.5V for falling VIN. For a VOUT of 3.3V, the VOUT value will

track VIN below 3.6V until the 2.5V falling VIN threshold is

reached.

If the UVLO falling threshold is met, the part shuts down

and will power up again with soft-start, when the UVLO rising

threshold is surpassed.

34726 Datasheet(PDF) 13 Page - Freescale Semiconductor, Inc