MPQ8632 HIGH EFFICIENCY 18V SYNCHRONOUS STEP-DOWN CONVERTER FAMILY FOR 4A TO 20A
PIN FUNCTIONS
MPQ8632GLE-4, MPQ8632GLE-6,
MPQ8632HGLE-10, MPQ8632GLE-12
MPQ8632GLE-8,
MPQ8632GLE-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
FB
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. MPQ8632 and MPQ8632H 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.
Soft Start. Connect an external capacitor to program the soft start time for the
switch mode regulator.
4
5
SS
AGND
Analog ground. The control circuit reference.
Power Good. The output is an open drain signal. Require a pull-up resistor to a DC
voltage to indicate high if the output voltage exceeds 91% of the nominal voltage.
There is a delay from FB ≥ 91% to PG goes high.
6
PG
Internal 4.8V LDO Output. Power the driver and control circuits. 5V external bias
can disable the internal LDO. 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
VCC
BST
IN
Bootstrap. Require a capacitor connected between SW and BST pins to form a
floating supply across the high-side switch driver.
8
Supply Voltage. Supply power to the internal MOSFET and regulator. The
MPQ8632 operates from a +2.5V to +18V input rail with 5V external bias and a
+4.5V to +18V input rail with internal bias. Require an input decoupling capacitor.
Connect using wide PCB traces and multiple vias.
9, 14
10-13
System Ground. Reference ground of the regulated output voltage. PCB layout
requires extra care. Connect using wide PCB traces.
PGND
Switch Output. Connect to the inductor and bootstrap capacitor. The high-side
switch drives the pin up to the 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 clamp the negative voltage.
Connect using wide PCB traces.
15, 16
SW
MPQ8632 Rev.1.24
8/28/2013
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