MIC2238_10 Datasheet, PDF (3/16 Pages) Micrel Semiconductor – 2.5MHz Dual Phase PWM Buck Regulator

Micrel, Inc.
Pin Description
Pin Number
Adjustable
1
Pin Number
Fixed
–
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
–
–
1
–
12
EP
EP
MIC2238
Pin Name Pin Name
FB2
EN2
AVIN
SW2
AGND
PGND
/FPWM
SW1
VIN
PGOOD
EN1
FB1
OUT2
OUT1
GND
Feedback 2: For adjustable voltage options connect the
external resistor divider network to FB2 to set the output
voltage of regulator 2. Nominal value is 0.8V.
Enable 2 input. Logic low powers down regulator 2. Logic
high powers up regulator 2. MIC2238 features built-in soft-
start circuitry that reduces in-rush current and prevents the
output voltage from overshooting at start up.
Analog Supply Voltage: Supply voltage for the analog control
circuitry. Requires bypass capacitor to GND.
Switch node for regulator 2, connected to external inductor.
Analog (signal) ground.
Power ground.
Forced PWM Mode Bar. Grounding this pin forces the device
to stay in constant frequency PWM mode only. Pulling this
pin high enables automatic Trickle mode operation.
Switch node for regulator 1, connected to external inductor.
Supply Voltage: Supply voltage for the internal switches and
drivers.
Power Good Output. This output is pulled down unless the
regulator 1 output voltage is within +6.25% and -8.5% of
regulation. After the output voltage is in regulation, the output
starts to go high with an internal 5μA current source. A delay
time could be programmed by tying a capacitor to this pin.
Enable 1 input. Logic low powers down regulator 1. Logic
high powers up regulator 1. MIC2238 features built-in soft-
start circuitry that reduces in-rush current and prevents the
output voltage from overshooting at start up.
Feedback 1: For adjustable voltage options connect to the
external resistor divider network to FB1 to set the output
voltage of regulator 1. Nominal value is 0.8V.
Output Voltage 2. For fixed output voltage options connect
OUT2 to the output voltage of regulator 2.
Output Voltage 1. For fixed output voltage options connect
OUT1 to the output voltage of regulator 1.
Ground, backside pad.
April 2010
3
M9999-040810-A