ir3840 International Rectifier Corp., ir3840 Datasheet - Page 4

• Manufacturer Part Number: ir3840
• Description: Integrated 12a Synchronous Buck Regulator
• Manufacturer: International Rectifier Corp.

Pin Description
Pin
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
02/09/09
SS/SD
PGood
Enable
Name
OCSet
Comp
PGnd
Boot
Gnd
Gnd
Seq
V
SW
V
Fb
Rt
CC
IN
¯¯
Sequence pin. Use two external resistors to set Simultaneous Power up
sequencing. If this pin is not used connect to Vcc.
Inverting input to the error amplifier. This pin is connected directly to the
output of the regulator via resistor divider to set the output voltage and
provide feedback to the error amplifier.
Output of error amplifier. An external resistor and capacitor network is
typically connected from this pin to Fb pin to provide loop
compensation.
Signal ground for internal reference and control circuitry.
Set the switching frequency. Connect an external resistor from this pin
to Gnd to set the switching frequency.
Soft start / shutdown. This pin provides user programmable soft-start
function. Connect an external capacitor from this pin to Gnd to set the
start up time of the output voltage. The converter can be shutdown by
pulling this pin below 0.3V.
Current limit set point. A resistor from this pin to SW pin will set the
current limit threshold.
Power Good status pin. Output is open drain. Connect a pull up resistor
from this pin to Vcc. If unused, it can be left open.
This pin powers the internal IC and the drivers. A minimum of 1uF high
frequency capacitor must be connected from this pin to the power
ground (PGnd).
Power Ground. This pin serves as a separated ground for the MOSFET
drivers and should be connected to the system’s power ground plane.
Switch node. This pin is connected to the output inductor.
Input voltage connection pin.
Supply voltage for high side driver. A 0.1uF capacitor must be
connected from this pin to SW.
Enable pin to turn on and off the device. Use two external resistors to
set the turn on threshold (see Enable section). Connect this pin to Vcc if
it is not used.
Signal ground for internal reference and control circuitry.
Description
IR3840MPbF
4