XRP7664-65-74-75
2A/3A 18V Synchronous Step-Down Regulator, Constant frequency
(XRP7664-65), Light-Load efficiency (XRP7674-75)
© 2014 Exar Corporation
2/8
Rev. 2.0.0
PIN ASSIGNMENT
Fig. 2: XRP7664-65-74-75 Pin Assignment, Exposed Pad applicable to XRP7665 and XRP7675
PIN DESCRIPTION
Name
Pin Number
Description
BS
1
Bootstrap pin. Connect a 0.01uF or larger bootstrap capacitor between the BS pin and
the SW pin. The voltage across the bootstrap capacitor drives the internal high-side
power MOSFET.
IN
2
Supply input pin. A capacitor should be connected between the IN pin and GND pin to
keep the input voltage constant.
SW
3
Power switch output pin. This pin is connected to the inductor and the bootstrap
capacitor.
GND
4
Ground pin.
FB
5
Feedback pin. An external resistor divider connected to FB programs the output voltage.
If the feedback pin exceeds 1.1V the over-voltage protection will trigger. If the
feedback voltage drops below 0.3V the oscillator frequency is lowered to short-circuit
protection.
COMP
6
Compensation pin. This is the output of transconductance error amplifier and the input
to the current comparator. It is used to compensate the control loop. Connect an RC
network form this pin to GND.
EN
7
Control input pin.
Drive EN high/low in order to turn on/off the regulator. When the IC is in shutdown
mode all functions are disabled to decrease the supply current below 0.1µA nominal.
SS
8
Soft-start control input pin. Connect a capacitor from SS to GND to set the soft-start
period. A 0.1µF capacitor sets the soft start period to 15ms. To disable the soft-start
feature, leave SS unconnected.
ORDERING INFORMATION
Refer to XRP7664-65-74-75’s datasheet and/or
www.exar.com
for exact and up to date ordering
information.
