MIC22405 Datasheet, PDF (3/30 Pages) Micrel Semiconductor – 4A Integrated Switch High-Efficiency Synchronous Buck Regulator

Micrel, Inc.
MIC22405
Pin Description (Continued)
Pin Number
18
19
20
EP
Pin Name
EN/DLY
NC
RC
GND
Description
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.
No Connect: Leave this pin open. Do not connect to ground or route other signal through this.
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.
Exposed Pad (Power): Must be connected to the GND plane for full output power to be realized.
June 2011
3
M9999-061511-A