MIC22705YML EV 
Evaluation Board 
1MHz, 7A Integrated Switch High-
Efficiency Synchronous Buck Regulator 
 
 
 
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. 
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com  
February 2011   M9999-020411-A 
 
General Description 
The  Micrel  MIC22705  is  a  high-efficiency,  7A,  integrated 
switch,  synchronous  buck  (step-down)  regulator.  The 
MIC22705  achieves  more  than  95%  efficiency  and 
switches at 1MHz. The ultra-high speed control loop keeps 
the  output  voltage  within  regulation  even  under  the 
extreme transient load  swings commonly found in  FPGAs 
and low-voltage ASICs. The output voltage is pre-bias safe 
and is adjustable down to 0.7V. 
The  MIC22705  offers  a  full  range  of  sequencing  and 
tracking  options.  The  Enable/Delay  (EN/DLY)  and  Power 
Good  (PG)  inputs  allow  versatile  turn-on  and  turn-off 
sequencing  across  multiple devices. The Ramp Control™ 
(RC)  input  allows  start-up  voltage  tracking,  either  directly 
or ratio-metrically. 
The MIC22705 is available in a 24-pin 4mm x 4mm MLF® 
with a junction operating range from –40° °C to +125 C. 
Data sheets and support documentation are found on the 
Micrel web site: www.micrel.com.  
Requirements 
The MIC22705YML EV requires a power supply of 2.9V to 
5.5V,  and  a  test  load.  Ensure  that  the power  supply  can 
provide the wattage required for the chosen test load. The 
load  can  be  active  (electronic  load)  or  passive  (resistor). 
Additionally,  monitor  the  Power  Good  output  (PG)  with  a 
multimeter or an oscilloscope if desired.  
Precautions 
There is  no  reverse  input  protection on  this  board. When 
connecting  supplies  and  signals  ensure  that  correct 
polarities are observed. 
 
Getting Started 
1.  VIN Supplies 
Connect the VIN supply (2.9V to 5.5V) across the PVIN and 
PGND  terminals.  Monitor  VIN  at  the  PVIN  and  PGND 
terminals with a voltmeter. 
2.  Enable/SHDN Inputs 
The  enable  input  EN  is  internally  pulled  up  with  a  1µA 
current  source.  When  external  on/off  control  is  desired, 
install Q1 and R5, and connect a logic level control signal 
to the SHDN input. When SHDN is high, the output is off, 
and when SHDN is low, the output is on. 
3.  Monitor Outputs 
Monitor  the  output  VOUT  with  a  scope  or  DVM  connected 
across the VOUT and PGND terminals. 
4.  Output Load 
Connect  a  load  across  the  VOUT  and  PGND  terminals. 
Use an active or passive load. 
5.  Turn On the Power 
Turn on the power supply and verify that VOUT = 1.8V. 
 
Ordering Information 
Part Number  Description 
MIC22705YML EV  Evaluation Board for the MIC22705YML