SP6122_04 Datasheet, PDF(4/19 Page) Sipex Corporation – Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters

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SP6122_04 Datasheet, PDF (4/19 Pages) Sipex Corporation – Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters

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PIN #

PIN NAME

VCC

FFLAG

VOUT

ENABLE

ISENSE

ISET

GND

PDRV

PIN DESCRIPTION

DESCRIPTION

Main Supply Pin: A RC filter as shown in the application circuit is

recommended. The decoupling capacitor needs to be close to the pin.

Fault Flag Pull-down Pin: Sinks current during a fault condition. Can

be hooked up to ENABLE to initiate Hiccup Timing.

Regulated Output Voltage: This voltage is divided internally and

compared to a 1.5%, 1.25V reference at the PFM comparator.

Enable Input: Floating this pin or pulling above 1.45V enables the

part. Pulling this pin to less than 0.9V will disable the part. A minimum

100pF capacitor is required between this pin and Ground to ensure

proper startup. If FFLAG is hooked to ENABLE, the capacitor on

ENABLE will control hiccup timing.

Negative Input to the Over Current Amplifier/Comparator: This input

is subtracted from the ISET input and gained by a factor of 3.3. The

output of this amplifier is compared with a 0.5V threshold, yielding a

150mV threshold. This threshold has a 3800 ppm/Â°C temperature

coefficient. If the subtraction exceeds 150mV, charge is pumped into

a capacitor until the capacitor hits VCC/2. At this time, the over current

fault is activated. If ISET = 0V and ISENSE = VCC, the part enters an

unprotected, 150ÂµA quiescent current mode.

Positive Input to the Over Current Amplifier: 20ÂµA flows into the ISET

pin if it is pulled through a resistor to VIN. This current has a

4300ppm/Â°C temperature coefficient and can be used via external

resistor to raise the overcurrent trip point from 150mV to some higher

value. If ISET = 0V and ISENSE = 0V, the part enters an unprotected,

250ÂµA quiescent current mode.

Power and Analog Ground: Hook directly to output ground.

Drive for PFET High Side Switch: 1nF/20ns Output Driver.

Date: 10/02/04

SP6122 Low Voltage, Micro 8, PFET, Buck Controller

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