MIC2204
Micrel, Inc.
MIC2204
High-Efficiency 2MHz Synchronous Buck Converter
General Description
The Micrel MIC2204 is a high-efficiency, 2MHz PWM syn-
chronous buck switching regulator. Power conversion effi-
ciency of above 95% is easily obtainable over a wide range
of applications. A proprietary internal compensation tech-
nique ensures stability with the smallest possible inductor
and ceramic output capacitor.
The MIC2204 operates from 2.3V to 5.5V input and features
internal power MOSFETs that can supply over 600mA of
output current with output voltages down to 1V. The MIC2204
implements a constant 2MHz pulse-width-modulation (PWM)
control scheme which reduces spurious noise in sensitive RF
and communication applications. Additionally, the MIC2204
can be synchronized to an external clock, or multiple MIC2204s
can easily be daisy-chained with the SYNCLOCK feature.
The MIC2204 has a high bandwidth loop (typ. 200kHz) which
allows ultra-fast transient response times. This is very useful
when powering applications that require fast dynamic re-
sponses, such as the CPU cores and RF circuitry in high-
performance cellular phones and PDAs.
The MIC2204 is available in 10-pin MSOP and 3mm
×
3mm
MLF™-10L package options with an operating junction tem-
perature range from –40°C to 125°C .
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Input voltage range: 2.3V to 5.5V
Output down to 1V/ 600mA
2MHz PWM operation
Ultra-fast transient response (typical 200kHz GBW)
Internal compensation
All ceramic capacitors
>95% efficiency
Fully integrated MOSFET switches
Easily synchronized to external clock
SYNCLOCK feature to daisy-chain multiple 2204s
<340µA quiescent current
Logic controlled micropower shutdown
Thermal shutdown and current limit protection
10-pin MSOP and 3mm×3mm MLF™-10L
–40°C to +125°C junction temperature range
Applications
•
•
•
•
•
•
High-efficiency portable power
Cellular phones
PDAs
802.11 WLAN power supplies
RF power supplies
Li Ion battery powered applications
Typical Application
4.7µH
MIC2204BMM
1
2.3V to 6V
SYNC_IN
3
SYNC_OUT
4
EN
5
6
7
10nF
8
2
10
EFFICIENCY (%)
3.3V
500mA
100
95
90
85
80
75
70
65
60
55
50
0
Efficiency
vs. Output Current
4.2V
IN
3.6V
IN
5V
IN
9
4.7µF
3.3V
OUT
100 200 300 400 500
OUTPUT CURRENT (mA)
Adjustable Output Synchronous Buck Converter
MLF and
MicroLeadFrame
are 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
April 2005
1
M9999-042205
MIC2204
Micrel, Inc.
Ordering Information
Part Number
MIC2204BMM
MIC2204YMM
MIC2204BML
MIC2204YML
Voltage
Adjustable
Adjustable
Adjustable
Adjustable
Junction Temp. Range
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
Package
10-pin MSOP
10-pin MSOP
10-pin MLF™
10-pin MLF™
Lead Finish
Standard
Lead-Free
Standard
Lead-Free
Pin Configuration
SW 1
VIN 2
SYNC_IN 3
SYNC_OUT 4
EN 5
10 GND
9 GND
8 GND
7 BIAS
6 FB
SW
VIN
SYNC_IN
SYNC_OUT
1
2
3
4
EN
5
10
GND
9
GND
8
GND
7
BIAS
6
FB
MSOP-10 (MM)
MLF-10 (ML)
Pin Description
Pin Number
1
2
3
Pin Name
SW
VIN
SYNC_IN
Pin Function
Switch (Output): Internal power MOSFET output switches.
Supply Voltage (Input): Requires bypass capacitor to GND.
SYNC_IN for the MIC2204: Sync the main switching frequency to an
external clock. Tie pin to ground if not using this function. Tying SYNC_IN
high reduces the switching frequency to 1.6MHz (See “Applications Informa-
tion” section).
SYNC_OUT an open collector output to feed into SYNC_IN. Float or ground
the SYNC_OUT pin if not using sync out function.
A low level EN will power down the device, reducing the quiescent current to
under 15µA (typ. 6.5µA).
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 with a 0.01µF capacitor.
Ground.
4
5
6
7
8, 9, 10
M9999-042205
SYNC_OUT
EN
FB
BIAS
GND
2
April 2005
MIC2204
Micrel, Inc.
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 –0.3V
Power Dissipation
(2)
Storage Temperature (T
S
) ....................... –65°C to +150°C
Operating Ratings
(3)
Supply Voltage (V
IN
) ................................... +2.3V to +5.5V
Junction Temperature (T
J
) ................ –40°C
≤
T
J
≤
+125°C
Package Thermal Resistance
MSOP (θ
JA
) ....................................................... 115°C/W
3mm×3mm MLF™-10L (θ
JA
) ............................... 60°C/W
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
=V
EN
= 3.5V, unless otherwise noted.
Bold
values indicate –40°C < T
J
< +125°C
Parameter
Supply Voltage Range
Current Limit
Quiescent Current
V
FB
= 0.7V
V
FB
= 1.1V
EN = 0V
Feedback Voltage
Output Voltage Line Regulation
Output Voltage Load Regulation
Maximum Duty Cycle
Switch On-Resistance
V
OUT
= 1V, V
IN
= 2.3V to 5.5V, I
LOAD
= 100mA
0mA < I
LOAD
< 500mA
V
FB
= 0.7V
I
SW
= 300mA, V
FB
= 0.7V
I
SW
= –300mA, V
FB
= 1.1V
Oscillator Frequency
Sync Frequency Range
SYNC_IN Threshold
Sync Minimum Pulse Width
SYNC_IN Input Current
Enable Threshold
Enable Hysteresis
Enable Input Current
Overtemperature Shutdown
Overtemperature Shutdown
Hysteresis
Notes:
1.
2.
3.
4.
Exceeding the ABSOLUTE MAXIMUM RATINGS may damage device.
Absolute maximum power dissipation is limited by maximum junction temperature where P
D(MAX)
= (T
J(MAX)
–T
A
)
÷
θ
JA
.
The device is not guaranteed to function outside its operating rating.
Specification for packaged product only.
Condition
Min
2.3
0.6
Typ
Max
5.5
Units
V
A
µA
µA
V
%
%
%
1.2
320
6.0
2
450
15
1.02
0.98
1.0
0.2
0.2
100
0.72
0.55
1.8
1.8
1.2
10
1
0.52
0.72
20
1
160
20
2
2
0.96
2
2.2
2.5
Ω
Ω
MHz
MHz
V
ns
µA
V
mV
µA
°C
°C
April 2005
3
M9999-042205
PCB设计
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