MIC2208
3mm x 3mm 1MHz 3A PWM Buck
Regulator
General Description
The Micrel MIC2208 is a high efficiency PWM buck (step-
down) regulator that provides up to 3A of output current.
The MIC2208 operates at 1MHz and has external
compensation that allows a closed loop bandwidth of over
100kHz.
The low on-resistance internal p-channel MOSFET of the
MIC2208 allows efficiencies over 94% reduces external
component count and eliminates the need for an
expensive current sense resistor.
The MIC2208 operates from 2.7V to 5.5V input and the
output can be adjusted down to 1V. The devices can
operate with a maximum duty cycle of 100% for use in low-
dropout conditions.
The MIC2208 is available in the exposed pad 12-pin
3mm x 3mm MLF
®
package with a junction operating
range from –40°C to +125°C.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
2.7 to 5.5V supply voltage
1MHz PWM mode
Output current to 3A
>90% efficiency
Adjustable output voltage option down to 1V
Ultra-fast transient response
External Compensation
Stable with a wide range of output capacitance
Fully integrated 5A MOSFET switch
Micropower shutdown
Thermal shutdown and current limit protection
Pb-free 12-pin 3mm x 3mm MLF
®
package
–40°C to +125°C junction temperature range
Applications
•
•
•
•
•
5V or 3.3V Point of Load Conversion
Telecom/Networking Equipment
Set Top Boxes
Storage Equipment
Video Cards
___________________________________________________________________________________________________________
Typical Application
3A 1MHz 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
May 2010
M9999-051410-D
Micrel, Inc.
MIC2208
Ordering Information
Part Number
MIC2208YML
Note:
MLF is GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Voltage
Adj.
Temperature Range
–40° to +125°C
Package
12-Pin 3x3 MLF
®
Lead Finish
Pb-Free
Pin Configuration
SW 1
VIN 2
PGND 3
SGND 4
BIAS 5
FB 6
EP
12 SW
11 VIN
10 PGND
9 PGOOD
8 EN
7 COMP
12-Pin 3mm x 3mm MLF
®
(ML)
Pin Description
Pin Number
1, 12
2, 11
3, 10
4
5
6
7
8
9
EP
Pin Name
SW
VIN
PGND
SGND
BIAS
FB
COMP
EN
PGOOD
GND
Pin Function
Switch (Output): Internal power P-Channel MOSFET output switch.
Supply Voltage (Input): Supply voltage for the source of the internal P-channel
MOSFET and driver. Requires bypass capacitor to GND
Power Ground. Provides the ground return path for the high-side drive current.
Signal Ground. Provides return path for control circuitry and internal reference.
Internal circuit bias supply. Must be bypassed with a 0.1µF ceramic capacitor to
SGND.
Feedback. Input to the error amplifier, connect to the external resistor divider
network to set the output voltage.
Compensation. This is the internal error amplifier output. Connect external
compensation components for type II or type III compensation.
Enable (Input). Logic level low will shutdown the device, reducing the current
draw to less than 5µA.
Power Good. Open drain output that is pulled to ground when the output voltage
is within ±7.5% of the set regulation voltage
Connect to ground.
May 2010
2
M9999-051410-D
Micrel, Inc.
MIC2208
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ........................................ –0.3V to +6V
Output Switch Voltage (V
SW
) .............................. –1V to +6V
Output Switch Current (I
SW
)............................................10A
Logic Input Voltage (V
EN
) .................................. –0.3V to V
IN
Storage Temperature (T
s
) ........................... –60°C to 150°C
ESD Rating
(3)
.......................................................2kV (HBM)
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +2.7V to +5.5V
Logic Input Voltage (V
EN
, V
LOWQ
)............................ 0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
3x3 MLF-12 (θ
JA
) ...............................................60°C/W
Electrical Characteristics
(4)
V
IN
= V
EN
= 3.6V; L = 1µH; C
OUT
= 4.7µF; T
A
= 25°C, unless noted.
Bold
values indicate –40°C< T
J
< +125°C.
Parameter
Supply Voltage Range
Under-Voltage Lockout
Threshold
UVLO Hysteresis
Quiescent Current
Shutdown Current
[Adjustable] Feedback
Voltage
FB pin input current
Current Limit in PWM Mode
Output Voltage Line
Regulation
Output Voltage Load
Regulation
PWM Switch ON-
Resistance
Oscillator Frequency
Enable Threshold
Enable Input Current
Soft Start Time
Over-Temperature
Shutdown
over-Temperature
Hysteresis
Power Good Range
Power Good Resistance
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, 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
Condition
(turn-on)
Min
2.7
2.45
Typ
2.55
100
Max
5.5
2.65
Units
V
V
mV
V
FB
= 0.9 * V
NOM
(not switching)
V
EN
= 0V
± 1%
± 2% (over temperature)
V
FB
= 0.9 * V
NOM
V
OUT
> 2.2V; V
IN
= V
OUT
+ 500mV to 5.5V; I
LOAD
= 20mA
V
OUT
< 2.2V; V
IN
= 2.7V to 5.5V; I
LOAD
= 20mA
20mA < I
LOAD
< 3A
I
SW
= 50mA V
FB
= 0.7V
FB_NOM
(High Side Switch)
0.9
0.5
V
OUT
=10% to V
OUT
= 90%
0.99
0.98
720
0.1
1
1
8
0.13
0.2
95
1
0.85
0.1
450
160
20
±7
950
5
1.01
1.02
100
10
µA
µA
V
V
nA
A
%
1
20
300
1.1
1.3
2
%
mΩ
mΩ
MHz
V
µA
µs
°C
°C
±10
250
%
Ω
I
PGOOD
145
May 2010
3
M9999-051410-D
Micrel, Inc.
MIC2208
Typical Characteristics
3.3V
96
94
EFFICIENCY (%)
92
90
88
86
84
82
80
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
5V
IN
5.5V
IN
OUT
MIC2208
Efficiency
4.5V
IN
1.8V
95
93
91
EFFICIENCY (%)
89
87
85
83
81
79
77
75
0
3V
OUT
MIC2208
Efficiency
90
88
86
EFFICIENCY (%)
84
82
80
78
76
74
72
70
0
MIC2208
1.8V
Efficiency
OUT
1.5V
95
90
EFFICIENCY (%)
85
80
75
70
0
3.3V
IN
OUT
MIC2208
Efficiency
IN
4.5V
IN
3V
IN
5V
IN
3.3V
IN
3.6V
IN
3.6V
IN
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
1.5V
85
83
81
79
77
75
73
71
69
67
65
0
OUT
MIC2208
Efficiency
4.5V
IN
EFFICIENCY (%)
85
83
81
79
77
75
73
71
69
67
65
0
1.2V
OUT
MIC2208
Efficiency
85
83
81
79
77
75
73
71
69
67
65
0
1.2V
OUT
MIC2208
Efficiency
3V
IN
3.3V
IN
EFFICIENCY (%)
EFFICIENCY (%)
5V
IN
4.5V
IN
5.5V
IN
3.6V
IN
5V
IN
5.5V
IN
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
Load Regulation
1.010
OUTPUT VOLTAGE (V)
1.008
1.006
1.004
1.002
1.000
0.998
0.996
0.994
0.992 3.3V
IN
0.990
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
1.0100
FEEDBACK VOLTAGE (V)
1.0080
1.0060
1.0040
1.0020
1.0000
0.9980
0.9960
0.9940
Feedback Voltage
vs. Temperature
1.20
FEEDBACK VOLTAGE (V)
1.15
1.10
1.05
1.00
0.95
0.90
Feedback Voltage
vs. Temperature
0
20
40
60
80
0
20
40
60
-40
-20
-40
100
120
-20
80
100
3
TEMPERATURE (°C)
TEMPERATURE (°C)
May 2010
4
M9999-051410-D
120
0.9920 3.3V
IN
0.9900
0.85 3.3V
IN
0.80
Micrel, Inc.
MIC2208
Typical Characteristics (continued)
1.2
FEEDBACK VOLTAGE (V)
1.0
0.8
0.6
0.4
0.2
0
0
1
2
3
4
5
SUPPLY VOLTAGE (V)
Feedback Voltage
vs. Supply Voltage
700
QUIESCENT CURRENT (µA)
600
500
400
300
200
100
0
0
Quiescent Current
vs. Supply Voltage
120
P-CHANNEL RDSON (mOhms)
115
110
105
100
95
90
85
80
75
70
2.7
RDSON
vs. Supply Voltage
1
2
3
4
5
SUPPLY VOLTAGE (V)
3.2 3.7 4.2 4.7 5.2
SUPPLY VOLTAGE (V)
160
P-CHANNEL RDSON (mOhms)
140
120
100
80
60
40
20
-40
0
RDSON
vs. Temperature
1.2
ENABLE THRESHOLD (V)
1
Enable Threshold
vs. Supply Voltage
1.2
ENABLE THRESHOLD (V)
1
Enable Threshold
vs. Temperature
0.8
0.6
0.4
0.2
0
2.7
3.2
3.7
4.2
4.7
SUPPLY VOLTAGE (V)
0.8
0.6
0.4
0.2
0
20
40
60
-40
-20
80
100
120
0
3.3V
IN
0
20
40
60
-20
80
100
TEMPERATURE (°C)
120
TEMPERATURE (°C)
Max. Continuous Current
vs. Ambient Temp 3.3V
*
3.5
MAX. OUTPUT CURRENT (A)
3
OUT
Max. Continuous Current
vs. Ambient Temp 2.5V
*
3.5
MAX. OUTPUT CURRENT (A)
3
OUT
Max. Continuous Current
vs. Ambient Temp 1.8V
*
3.5
MAX. OUTPUT CURRENT (A)
3
OUT
*Using recommended
layout (1oz copper)
and B.O.M.
2.5
2
2.5
2
3.3V
IN
*Using
recommended
layout (1oz copper)
and B.O.M.
2.5
2
3.3V
IN
5V
IN
1.5
1
5V
IN
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
1.5
1
5V
IN
1.5
1
*Using
0.5
0.5
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
0.5
layout (1oz copper)
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
and B.O.M.
recommended
Max. Continuous Current
vs. Ambient Temp 1.0V
*
3.5
MAX. OUTPUT CURRENT (A)
3
OUT
2.5
2
3.3V
IN
5V
IN
1.5
1
*Using
0.5
layout (1oz copper)
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
and B.O.M.
recommended
May 2010
5
M9999-051410-D
微控制器 MCU
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