MIC22705 Datasheet, PDF (2/28 Pages) Micrel Semiconductor – 1MHz, 7A Integrated Switch High-Efficiency Synchronous Buck Regulator

Micrel, Inc.
Ordering Information
Part Number
Voltage
MIC22705YML
Adjustable
Note:
1. Other Voltage available. Contact Micrel for details.
Junction Temperature Range
–40°C to +125°C
Package
24-Pin 4x4 MLF^®
Pin Configuration
MIC22705
Lead Finish
Pb-Free
24-Pin 4mm × 4mm MLF^® (ML)
Pin Description
Pin Number
Pin Name
1, 6, 13, 18
PVIN
2
EN/DLY
3
DELAY
4
RC
5
PG
14
FB
Description
Power Supply Voltage (Input): The PVIN pins are the input supply to the internal P-Channel
Power MOSFET. A 22µF ceramic is recommended for bypassing at each PVIN pin. The SVIN
pin must be connected to a PVIN pin.
Enable/Delay (Input): This pin is internally fed with a 1µA current source from SVIN. A delayed
turn on is implemented by adding a capacitor to this pin. The delay is proportional to the
capacitor value. The internal circuits are held off until EN/DLY reaches the enable threshold of
1.24V. This pin is pulled low when the input voltage is lower than the UVLO threshold.
Delay (Input): Capacitor to ground sets internal delay timer. Timer delays Power Good (PG)
output at turn-on and ramp down at turn-off.
Ramp Control: A capacitor from the RC pin-to-ground determines slew rate of output voltage
during start-up. The RC pin is internally fed with a 1µA current source. The output voltage tracks
the RC pin voltage. The slew rate is proportional by the internal 1µA source and RC pin
capacitor. This feature can be used for tracking capability as well as soft start.
PG (Output): This is an open drain output that indicates when the output voltage is below 90% of
its nominal voltage. The PG flag is asserted without delay when the enable is set low or when the
output goes below the 90% threshold.
Feedback: Input to the error amplifier. The FB pin is regulated to 0.7V. A resistor divider
connecting the feedback to the output is used to adjust the desired output voltage.
December 2010
2
M9999-121710-A