MIC22400 Datasheet, PDF (3/19 Pages) Micrel Semiconductor – 4A Integrated Switch Synchronous Buck Regulator with Frequency Programmable up to 4MHz

Micrel, Inc.
MIC22400
Pin Description
Pin Number
MLF-20
1
Pin Number
e-TSSOP-20
4
2
3, 5, 9
4
5
7, 12, 19
6
6
8
7
8
10, 17
11, 16
12, 13, 14, 15
18
9
10
11, 20
13, 18
14, 15, 16, 17
1
19
2
20
3
EP
EP
Pin Name Description
POR
CF
NC
COMP
FB
SGND
SVIN
PVIN
PGND
SW
EN
DELAY
RC
GND
Power On Reset (Output): Open-drain output device indicates when the output is
out of regulation and is active after the delay set by the delay pin.
Adjustable frequency with external capacitor.
Not connected internally.
Compensation pin (Input): Place a RC to GND to compensate the device, see
applications section.
Feedback: Input to the error amplifier, connect to the external resistor divider
network to set the output voltage.
Signal Ground (Signal): Ground
Signal Power Supply Voltage (Input): Requires bypass capacitor to GND.
Power Supply Voltage (Input): Requires bypass capacitor to GND.
Power Ground (Signal): Ground
Switch (Output): Internal power MOSFET output switches.
Enable (Input): When this pin is pulled higher than the enable threshold, the part
will start up. Below this voltage the device is in its low quiescent current mode.
The pin has a 1µA current source charging it to VIN. By adding a capacitor to this
pin a delay may easily be generated. The enable function will not operate with an
input voltage lower than the min specified.
Delay (Input): Capacitor-to-ground sets internal delay timer. Timer delays power-
on reset (POR) output at turn-on and ramp down at turn-off.
Ramp Control: Capacitor to ground from this pin determines slew rate of output
voltage during start-up. This can be used for tracking capability as well as soft
start.
Exposed Pad (Power): Must make a full connection to a GND plane for full output
power to be released.
February 2008
3
M9999-022108-A