MIC2203
High Efficiency 1MHz Synchronous
Buck Regulator
General Description
The Micrel MIC2203 is a high efficiency 1MHz PWM
synchronous buck switching regulator. The MIC2203
features low noise constant frequency PWM
operation with a low dynamic supply current of
<1mA. The low noise and efficient operation both
make the MIC2203 well suited for sensitive RF, and
audio power applications.
The MIC2203 operates from 2.3V to 5.5V input and
can supply over 300mA of output current with output
voltages down to 0.5V. Additionally, the MIC2203
can be synchronized to an external clock, or multiple
MIC2203s can easily be daisy-chained with the
SYNCLOCK feature.
The MIC2203 has a high loop bandwidth with
corresponding ultra fast transient response times.
This reduces the output capacitor size, and is very
useful when powering applications that require fast
dynamic response such as CPU cores and RF
circuitry in high performance cellular phones and
PDAs.
The MIC2203 is available in 10-pin MSOP and
3mm x 3mm MLF™-10L package options with an
operating junction temperature range from –40ºC to
125ºC.
Features
•
•
•
•
•
•
•
•
•
•
•
Input voltage range: 2.3V to 5.5V
Output voltage adjustable down to 0.5V
300mA output current
Constant 1MHz PWM switching frequency
> 95% efficiency
< 1mA switching supply current
< 350µA static quiescent current
< 1µA shutdown current
All-ceramic capacitors
Easily synchronized to external clock
SYNCLOCK feature to daisy chain multiple
devices
•
Thermal shutdown and current limit protection
•
10 pin MSOP, and 3mm x 3mm MLF-10L package
options
•
–40ºC to +125ºC junction temperature range
Applications
•
802.11 WLAN modules
•
MD players
•
MP3 players
_____________________________________________________________________
Typical Application
10µH
MIC2203BMM
2.3V to 5.5V
SYNC_IN
1µF
SYNC_OUT
EN
1
2
3
4
5
10
9
8
7
6
10nF
R2
3.83k
R1
10k
2.2µF
1.8V
300mA
High Efficiency Buck Regulator
MicroLead Frame and MLF are trademarks of Amkor Technologies.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax +1 (408) 474-1000 • http://www.micrel.com
December 2004
M9999-120604
(408) 955-1690
Micrel, Inc.
MIC2203
Ordering Information
Part Number
Standard
Pb-Free
MIC2203BMM MIC2203YMM
MIC2203BML
MIC2203YML
Output Voltage
Adjustable
Adjustable
Junction Temperature
Range
-40°C to +125°C
-40°C to +125°C
Package
MSOP-10L
3mm x 3mm MLF-10L
Pin Configuration
MSOP-10 (MM)
MLF-10 (ML)
Top View
Pin Description
Pin Number
1
2
3
4
5
6
7
8,9,10
EP
Pin Name
SW
VIN
SYNC_IN
SYNC_OUT
EN
FB
BIAS
GND
GND
Pin Function
Switch (Output): Internal power MOSFET output switches.
Supply Voltage (Input): Requires a bypass capacitor to GND.
SYNC_IN for the MIC2203, Sync the main switching frequency to a external
clock. Should be tied to ground when not in use.
SYNC_OUT a 50ns wide sync pulse to feed into SYNC_IN on MIC2203.
Can be left open or tied to ground when not used.
A low level EN will power down the device, reducing the quiescent current to
under 1µA.
Input to the error amplifier, connect to the external resistor divider network to set
the output voltage.
Internal circuit bias supply, nominally 2.3V. Must be de-coupled to signal ground
and can have a minimum of external DC loading.
Ground
Exposed backside pad, connect to Ground (MLF option only)
December 2004
2
M9999-120604
(408) 955-1690
Micrel, Inc.
MIC2203
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .............................................. 6V
Output Switch Voltage (V
SW
) ................................. 6V
Logic Input Voltage (V
EN
, V
SYNC_IN
) .............V
IN
to –3V
Power Dissipation ............................................Note
5
Storage Temperature (T
s
)............... –65°C to +150°C
ESD Rating
(3)
........................................................2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)................................2.3V to 5.5V
Junction Temperature Range ......... –40°C to +125°C
Package Thermal Resistance
MSOP-10L (θ
JA
)..................................... 115°C/W
3mmX3mm MLF-10L (θ
JA
)....................... 60°C/W
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
= V
EN
= 3.5V, unless otherwise specified.
Bold
values indicate –40ºC < T
J
< +125ºC
Parameter
Supply Voltage Range
Quiescent Current
No Load Supply Current
MIC2203 [Adjustable]
Feedback Voltage
Output Voltage Line
Regulation
Output Voltage Load
Regulation
Bias Regulator Output
Voltage
Maximum Duty Cycle
Current Limit
Switch ON-Resistance
Enable Input Current
Sync Frequency Range
SYNC_IN Threshold
Sync Minimum Pulse
Width
SYNC_IN Input Current
Oscillator Frequency
Enable Threshold
Enable Hysteresis
Over Temperature
Shutdown
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. Absolute maximum power dissipation is limited by maximum junction temperature where P
D(MAX)
= (T
J(MAX)
– T
A
) ÷
θ
JA.
Condition
V
FB
= 0.6V (not switching)
EN = 0V (shutdown)
(switching)
Min
2.3
Typ
320
0.01
870
Max
5.5
450
1
0.5125
0.5
0.5
2.6
Units
V
µA
µA
µA
V
%
%
V
%
0.4875
V
OUT
< 2V; V
IN
= 2.3V to 5.5V, I
LOAD
= 50mA
0mA < I
LOAD
< 300mA
2.2
V
FB
≤
0.4V
V
FB
= 0.4V
I
SW
= 300mA V
FB
= 0.4V
I
SW
= -300mA V
FB
= 0.6V
0.8
0.7
100
0.375
0.5
0.13
0.2
2.32
0.6
1.5
1
0.01
1
10
1.5
2.2
1.6
2
1.25
1.7
A
Ω
µA
MHz
V
ns
1
0.8
0.5
1
0.7
20
Hysteresis
160
20
1.2
1.3
µA
MHz
V
mV
°C
December 2004
3
M9999-120604
(408) 955-1690
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