MIC2225
2MHz 600mA Synchronous Buck
Regulator with 300mA LDO
General Description
The Micrel MIC2225 is a dual output regulator featuring a
high efficiency 2MHz PWM synchronous buck (step-down)
regulator and a 300mA LDO. The MIC2225 is an ultra-low
noise, small size, and high efficiency solution for portable
power applications, providing core and I/O supply rails for
applications like application processors, camera DSPs and
multimedia chipsets.
In PWM mode, the MIC2225 operates with a constant
2MHz frequency. The MIC2225 switching regulator
operates from 2.7V to 5.5V input and features internal
power MOSFETs that can supply up to 600mA output
current in PWM mode.
The MIC2225 is available in the 10-pin 2mm x 2mm Thin
MLF
®
package with a junction operating range from –40°C
to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
DC-DC Converter
•
2.7 to 5.5V supply voltage
•
2MHz PWM mode
•
Output current to 600mA
•
>95% efficiency
•
100% maximum duty cycle
•
Fixed output voltage option down to 1V
•
Ultra-fast transient response
•
Stable with 2.2µF ceramic output capacitor
•
Fully integrated MOSFET switches
•
Micropower shutdown (1mA in shutdown)
•
Thermal shutdown and current limit protection
•
Pb-free 10-pin 2mm x 2mm Thin MLF
®
package
•
–40°C to +125°C junction temperature range
LDO
•
V
IN
range 2.7V to 5.5V
•
300mA output current
•
Output voltage down to 0.8V
•
Thermal shutdown protection
•
Current limit protection
Applications
•
Cellular phones
•
PDAs
•
USB peripherals
___________________________________________________________________________________________________________
Typical Application
1.8V Efficiency @ 25°C
100
90
80
70
60
50
40
30
20
10
0
0
3.6V
IN
2.7V
IN
5.5V
IN
0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6
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 2008
M9999-022008-D
Micrel, Inc.
MIC2225
Ordering Information
Part Number
MIC2225-4KYMT
MIC2225-4MYMT
MIC2225-4OYMT
MIC2225-4SYMT
MIC2225-G4YMT
MIC2225-GFYMT
MIC2225-GJYMT
MIC2225-GMYMT
Note:
MLF® is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Other voltage options available. Please contact Micrel for details.
* Refers to nominal output voltage of DC/DC and LDO respectively.
Marking
Code
4TK
4TM
4TO
4TS
GT4
GTF
GTJ
GTM
Voltage*
1.2V/2.6V
1.2V/2.8V
1.2V/2.9V
1.2V/3.3V
1.8V/1.2V
1.8V/1.5V
1.8V/2.5V
1.8V/2.8V
Temperature Range
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
Package
10-Pin 2x2 Thin MLF
®
10-Pin 2x2 Thin MLF
10-Pin 2x2 Thin MLF
®
®
Lead Finish
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
10-Pin 2x2 Thin MLF
®
10-Pin 2x2 Thin MLF
®
10-Pin 2x2 Thin MLF
®
10-Pin 2x2 Thin MLF
®
10-Pin 2x2 Thin MLF
®
Pin Configuration
AGND
LDO
BIAS
AVIN
FB
1
2
3
4
5
10 PGND
9
8
7
6
SW
VIN
ENLDO
EN
10-Pin 2mm x 2mm Thin MLF
®
(MT)
February 2008
2
M9999-022008-D
Micrel, Inc.
MIC2225
Pin Description
Pin Number
1
2
3
4
Pin Name
AGND
LDO
BIAS
AVIN
Pin Function
Analog (signal) Ground.
LDO Output (Output): Connect to a 2.2µF output capacitor.
Internal circuit bias supply. Must be de-coupled to signal ground with a 0.1µF
capacitor and should not be loaded.
Analog Supply Voltage (Input): Supply voltage for the analog control circuitry
and LDO input power. Requires bypass capacitor to GND. It must be tied to
VIN.
Feedback. Input to the error amplifier. For the Adjustable option, connect to the
external resistor divider network to set the output voltage. For fixed output
voltage options, connect to V
OUT
and an internal resistor network sets the output
voltage.
Enable (Input). Logic low will shut down the switching regulator reducing the
quiescent current to less than 5µA.
Enable LDO (Input): Logic low will shut down the LDO, reducing the quiescent
current to less than 5µA.
Supply Voltage (Input): Supply voltage for the internal switches and drivers.
Switch (Output): Internal power MOSFET output switches.
Power Ground.
5
FB
6
7
8
9
10
EN
ENLDO
VIN
SW
PGND
February 2008
3
M9999-022008-D
Micrel, Inc.
MIC2225
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .......................................................+6V
Output Switch Voltage (V
SW
) ..........................................+6V
Output Switch Current (I
SW
)..............................................1A
Logic Input Voltage (V
EN
,V
LOWQ
)........................ –0.3V to V
IN
Storage Temperature (T
s
) .........................–60°C to +150°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +2.7V to +5.5V
Logic Input Voltage (V
EN
,V
LOWQ
)........................ –0.3V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
Thin MLF-10L (θ
JA
) ............................................90°C/W
Electrical Characteristics DC/DC
(4)
V
EN
= V
IN
= 3.6V, L = 2.2µH; C
OUTDC/DC
= 2.2µF, C
LDO
= 2.2µF; I
OUTDC/DC
= 100mA; C
BIAS
= 0.1µF
V
ENLDO
= 0V; T
J
= 25°C,
bold
values indicate –40°C < T
J
< +125°C; unless noted.
Parameter
UVLO Threshold
UVLO Hysteresis
Switcher Ground Pin Current
LDO Ground Pin Current
Ground Pin Current in
Shutdown
Over-temperature Shutdown
Over-temperature Shutdown
Hysteresis
Enable Input Voltage
Enable Input Current
Turn-on Time
Fixed Output Voltages
Current Limit in PWM Mode
Output Voltage Line Regulation
Output Voltage Load Regulation
Maximum Duty Cycle
PWM Switch ON-Resistance
Oscillator Frequency
Logic Low
Logic High
V
IL
< 0.2V
V
IH
> 1.0V
I
LOAD
= 5mA
Nominal V
OUT
tolerance Io=50mA
V
FB
= 0.9*V
NOM
V
IN
= 2.7V to 5.5V, I
LOAD
= 100mA
20mA < I
LOAD
< 300mA
V
FB
≤
0.4V
I
SW
= 150mA; V
FB
= 0.7V
FB_NOM
I
SW
= -150mA; V
FB
= 1.1V
FB_NOM
1.8
100
0.4
0.4
2
2.2
–2
–3
0.675
0.95
0.12
0.2
1
1.5
1.0
0.1
0.1
50
+2
+3
1
1
ENLDO = 0V, V
FB
= GND ; I
L
=0mA
EN = 0V
EN +ENLDO = 0V
Condition
Rising input voltage during turn-on
Min
2.45
Typ
2.55
70
850
67
0.2
160
23
0.2
1100
110
5
Max
2.65
Units
V
mV
µA
µA
µA
°C
°C
V
V
µA
µA
µs
%
%
A
%
%
%
%
Ω
Ω
MHz
February 2008
4
M9999-022008-D
Micrel, Inc.
MIC2225
Electrical Characteristics LDO
(4)
C
OUTLDO
= 2.2µF, I
OUTLDO
= 100µA; T
J
= 25°C,
bold
values indicate –40°C < T
J
< +125°C; unless noted.
Parameter
Input Voltage
Output Voltage Accuracy
Line Regulation
Turn-on Time
Load Regulation
Dropout Voltage,
Note 5
Ripple Rejection
Current Limit
Output Voltage Noise
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Specification for packaged product only.
5. Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value that is initially measured at
a 1V differential. For outputs below 2.7V, the dropout voltage is the input-to-output voltage differential with a minimum input voltage of 2.7V.
Condition
Variation from nominal V
OUT
Variation from nominal V
OUT
; –40°C to +125°C
V
IN
= V
OUT
+1V to 5.5V; I
OUT
= 100µA
I
LOAD
= 300mA
I
OUT
= 100µA to 300mA @ V
IN
= V
OUT
+ 1
I
OUT
= 300mA @ V
IN
= 2.7V
f = 1kHz; C
OUT
= 2.2µF
f = 20kHz; C
OUT
= 2.2µF
V
OUT
= 0V
C
OUT
= 2.2µF, 10Hz to 100kHz
Min
2.7
–2.0
–3.0
Typ
Max
5.5
+2.0
+3.0
Units
V
%
%
%
µs
%
mV
dB
dB
mA
µV
RMS
0.2
30
0.70
210
43
17
400
470
February 2008
5
M9999-022008-D
嵌入式系统
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