MPQ8636-10_MPQ8636H-10 — 10A, 18V, SYNCHRONOUS, STEP-DOWN CONVERTER
PIN FUNCTIONS
MPQ8636GL-10, MPQ8636HGL-10
PIN #
Name
Description
Enable. Digital input that turns the regulator on or off. Drive EN high to turn on the
regulator; drive it low to turn it off. Connect EN to IN through a pull-up resistor or a
resistive voltage divider for automatic startup. Do not float this pin.
1
EN
Frequency Set. Require a resistor connected between FREQ and IN to set the switching
frequency. The input voltage and the resistor connected to the FREQ pin determine the
ON time. The connection to the IN pin provides line feed-forward and stabilizes the
frequency during input voltage’s variation.
2
3
FREQ
Feedback. Connect to the tap of an external resistor divider from the output to GND to
set the output voltage. FB is also configured to realize over-voltage protection (OVP) by
monitoring output voltage. MPQ8636-10 and MPQ8636H-10 provide different OVP
mode. Please refer to the section “Over-Voltage-Protection (OVP)”. Place the resistor
divider as close to FB pin as possible. Avoid using vias on the FB traces.
FB
SS
Soft-Start. Connect an external capacitor to program the soft start time for the switch
mode regulator.
4
5
AGND Analog Ground. The control circuit reference.
Power-Good. The output is an open drain signal. Requires a pull-up resistor to a DC
6
PG
voltage to indicate HIGH if the output voltage exceeds 91% of the nominal voltage.
There is a delay from FB ≥ 91% to when PG goes high.
Internal 4.8V LDO Output. Powers the driver and control circuits. Decouple with a ≥1µF
ceramic capacitor as close to the pin as possible. For best results, use X7R or X5R
dielectric ceramic capacitors for their stable temperature characteristics.
7
8
VCC
BST
Bootstrap. Require a capacitor connected between SW and BST pins to form a floating
supply across the high-side switch driver.
Switch Output. Connect to the inductor and bootstrap capacitor. The high-side switch
drives these pins up to VIN during the PWM duty cycle’s ON time. The inductor current
drives the SW pin negative during the OFF-time. The low-side switch’s ON-resistance
and the internal Schottky diode holds the negative voltage. Connect using wide PCB
traces.
9,10
SW
System Ground. Reference ground of the regulated output voltage. PCB layout requires
extra care. Connect using wide PCB traces.
11,12
13
PGND
IN
Supply Voltage. Supplies power to the internal MOSFET and regulator. The MPQ8636-
10/MPQ8636H-10 operates from a 4.5V-to-18V input rail. Requires an input decoupling
capacitor. Connect using wide PCB traces and multiple vias.
MPQ8636-10, MPQ8636H-10 Rev. 1.22
www.MonolithicPower.com
6
8/2/2013
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