MP1584 – 3A, 1.5MHz, 28V STEP-DOWN CONVERTER
PIN FUNCTIONS
SOIC
Pin #
1
2
3
4
Name
SW
EN
COMP
FB
Description
Switch Node. This is the output from the high-side switch. A low forward drop Schottky diode to
ground is required. The diode must be close to the SW pins to reduce switching spikes.
Enable Input. Pulling this pin below the specified threshold shuts the chip down. Pulling it up
above the specified threshold or leaving it floating enables the chip.
Compensation. This node is the output of the error amplifier. Control loop frequency
compensation is applied to this pin.
Feedback. This is the input to the error amplifier. The output voltage is set by a resistive divider
connected between the output and GND which scales down V
OUT
equal to the internal +0.8V
reference.
5
6
7
8
GND
Ground. It should be connected as close as possible to the output capacitor to shorten the high
Exposed
current switch paths. Connect exposed pad to GND plane for optimal thermal performance.
Pad
Switching Frequency Program Input. Connect a resistor from this pin to ground to set the
FREQ
switching frequency.
Input Supply. This supplies power to all the internal control circuitry, both BS regulators and the
VIN
high-side switch. A decoupling capacitor to ground must be placed close to this pin to minimize
switching spikes.
Bootstrap. This is the positive power supply for the internal floating high-side MOSFET driver.
BST
Connect a bypass capacitor between this pin and SW pin.
MP1584 Rev. 1.0
8/8/2011
www.MonolithicPower.com
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