MIC23303 
4MHz PWM 3A Buck Regulator with 
HyperLight Load and Power Good 
 
 
 
 
General Description  Features 
The MIC23303 is a high-efficiency 4MHz 3A synchronous  Input voltage: 2.7V to 5.5V 
buck regulator with HyperLight Load mode, Power Good 
 Output voltage: down to 0.65 
output indicator, and programmable soft-start. HyperLight 
 Up to 3A output current 
Load provides very high efficiency at light loads and ultra-
 Up to 93% peak efficiency  
fast transient response, which makes the MIC23303 
perfectly suited for supplying processor core voltages. An  80% typical efficiency at 1mA 
additional benefit of this proprietary architecture is very low 
 Power Good output 
output ripple voltage throughout the entire load range with 
 Programmable soft-start 
the use of small output capacitors. The tiny 3mm  3mm 
 24A typical quiescent current 
DFN package saves precious board space and requires 
 4MHz PWM operation in continuous mode 
only six external components. 
 Ultra-fast transient response 
The MIC23303 is designed for use with a very small 
 Low ripple output voltage 
inductor, down to 0.33H, and an output capacitor as small 
as 10F that enables a total solution size less than 1mm in 
 35mVpp ripple in HyperLight Load mode 
height.  
 5mV output voltage ripple in full PWM mode 
The MIC23303 has very low quiescent current of 24A and 
 Fully-integrated MOSFET switches 
can achieve peak efficiency of 93% in continuous 
 0.01A shutdown current 
conduction mode. In discontinuous conduction mode, the 
 Thermal-shutdown and current-limit protection 
MIC23303 can achieve 80% efficiency at 1mA. 
 12-pin 3mm  3mm DFN 
 
The MIC23303 is available in a 12-pin 3mm  3mm DFN
 40C to +125C junction temperature range 
package with an operating junction temperature range 
from 40C to +125C. 
Applications 
Datasheets and support documentation are available on 
 Portable media/MP3 players 
Micrels web site at: www.micrel.com.  
 Portable navigation devices (GPS) 
 WiFi/WiMax/WiBro modules 
 Digital Cameras 
 Wireless LAN cards 
 Portable applications 
 
Typical Application 
 
 
 
 
HyperLight Load is a trademark of Micrel, Inc. 
 
 
Micrel Inc.  2180 Fortune Drive  San Jose, CA 95131  USA  tel +1 (408) 944-0800  fax + 1 (408) 474-1000  Micrel, Inc. MIC23303 
 
Ordering Information 
Marking Nominal Output Junction 
Part Number Package 
Code Voltage Temperature Range 
(1, 2)
MIC23303YML WYA Adjustable 40C to +125C 12-Pin 3mm  3mm DFN 
Notes: 
1. DFN is a GREEN RoHS compliant package.  Lead finish is NiPdAu.  Mold compound is Halogen Free. 
2. DFN Pin 1 identifier is  . 
 
 
Pin Configuration 
 
 
3mm x 3mm DFN (ML) 
(Top View) 
 
Pin Description 
Pin Number 
Pin Name Pin Function 
(Adjustable) 
1, 2 SW Switch (Output): Internal power MOSFET output switches. 
Power Good: Open-drain output for the power good indicator. Use a pull-up resistor from 
3 PG 
this pin to a voltage source to detect a power good condition. 
Enable (Input): Logic high enables operation of the regulator. Logic low shuts down the 
4 EN 
device. Do not leave floating. 
5 SNS Sense: Connect to V as close to output capacitor as possible to sense output voltage. 
OUT
6 FB Feedback: Connect a resistor divider from the output to ground to set the output voltage. 
Soft Start: Place a capacitor from this pin to ground to program the soft start time. Do not 
7 SS 
leave floating, 2.2nF minimum C is required. 
SS
Analog Ground: Connect to central ground point where all high current paths meet (C , 
IN
8 AGND 
C , and PGND) for best operation. 
OUT
9 AVIN Supply Voltage (Power Input): Analog control circuitry. Connect to PVIN. 
10, 11 PVIN Input Voltage: Connect a capacitor to ground to decouple the noise. 
12 PGND Power Ground. 
EP ePad Thermal pad: Connect to Ground plane for improved heat sinking. 
  
090613-2.0  
September 6, 2013 2