MIC2208
3mmx3mm 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 3mm x
3mm MLF-12L package with a junction operating
range from –40°C to +125°C.
Features
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•
•
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•
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•
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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 3mm x 3mm MLF-10L package
–40°C to +125°C junction temperature range
Internal soft-start
5V or 3.3V Point of Load Conversion
Telecom/Networking Equipment
Set Top Boxes
Storage Equipment
Video Cards
Applications
Typical Application
MIC2208
3A 1MHz Buck Regulator
MLF and
MicroLeadFrame
are trademarks of Amkor Technology
Micrel, Inc • 2180 Fortune Drive • San Jose, Ca 95131 • USA • tel +1 (408) 944-0800 • fax +1 (408) 474-1000 • http://www.micrel.com
September 2005
M9999-092905
www.micrel.com
Micrel, Inc.
MIC2208
Ordering Information
Part Number
MIC2208YML
.
Output
Voltage
(1)
Adj.
Junction Temp. Range
–40° to +125°C
Package
3mmx3mm MLF-10L
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
3mm x 3mm MLF-12 (ML)
Pin Description
Pin Number
1,12
2,11
Pin Name
SW
VIN
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 0.1uF 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 5uA.
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.
3,10
4
5
6
7
8
9
EP
PGND
SGND
BIAS
FB
COMP
EN
PGOOD
GND
September 2005
2
M9999-092905
www.micrel.com
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
3mmx3mm MLF-12L (θ
JA
) ....................... 60°C/W
Electrical Characteristics
(4)
V
IN
= V
EN
= 3.6V; L = 1
µ
H; C
OUT
= 4.7
µ
F; 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:
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
720
0.1
0.99
0.98
1
1
950
5
1.01
1.02
µA
µA
V
nA
A
%
±
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)
100
10
8
0.13
0.2
95
1
200
%
m
Ω
MHz
V
µA
µs
300
0.9
0.5
V
OUT
=10% to V
OUT
=90%
1
0.85
0.1
450
160
20
±7
I
PGOOD
145
±10
1.1
1.3
2
°
C
°
C
%
200
Ω
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.
September 2005
3
M9999-092905
www.micrel.com
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
EFFICIENCY (%)
100
98
96
94
92
90
88
86
84
82
80
0
2.5V
OUT
MIC2207
Efficiency
94
92
EFFICIENCY (%)
90
88
86
84
82
2.5V
OUT
MIC2207
Efficiency
IN
4.5V
3.3V
IN
3.6V
IN
5V
IN
5.5V
IN
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
80
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
1.8V
95
93
EFFICIENCY (%)
91
89
87
85
83
81
79
77
75
0
3V
OUT
MIC2208
Efficiency
90
88
EFFICIENCY (%)
86
84
82
80
78
76
74
72
70
0
1.8V
OUT
IN
MIC2208
Efficiency
95
90
EFFICIENCY (%)
85
80
75
70
0
1.5V
OUT
MIC2208
Efficiency
4.5V
IN
3V
IN
3.3V
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
EFFICIENCY (%)
81
79
77
75
73
71
69
67
65
0
5V
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
EFFICIENCY (%)
81
79
77
75
73
71
69
67
65
0
1.2V
OUT
MIC2208
Efficiency
3V
IN
3.3V
IN
4.5V
IN
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
1.008
OUTPUT VOLTAGE (V)
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
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
100
120
80
100
3
TEMPERATURE (°C)
TEMPERATURE (°C)
September 2005
4
M9999-092905
www.micrel.com
120
-40
-20
-40
-20
0.9940
0.9920 3.3V
IN
0.9900
0.85 3.3V
IN
0.80
Micrel, Inc.
MIC2208
1.2
FEEDBACK VOLTAGE (V)
1.0
0.8
0.6
0.4
0.2
0
0
Feedback Voltage
vs. Supply Voltage
700
QUIESCENT CURRENT (µA)
600
500
400
300
200
100
0
0
Quiescent Current
vs. Supply Voltage
P-CHANNEL RDSON (mOhms)
120
115
110
105
100
95
90
85
80
75
70
2.7
RDSON
vs. Supply Voltage
1
2
3
4
5
SUPPLY VOLTAGE (V)
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
80
100
120
-40
-20
0
3.3V
IN
0
20
40
60
80
100
TEMPERATURE (°C)
120
-20
TEMPERATURE (°C)
3.5
MAX. OUTPUT CURRENT (A)
3
Max. Continuous Current
vs. Ambient Temp 3.3V
OUT
*
*Using recommended
layout (1oz copper)
and B.O.M.
3.5
MAX. OUTPUT CURRENT (A)
3
Max. Continuous Current
vs. Ambient Temp 2.5V
OUT
*
*Using
recommended
layout (1oz copper)
and B.O.M.
3.5
MAX. OUTPUT CURRENT (A)
3
Max. Continuous Current
vs. Ambient Temp 1.8V
OUT
*
2.5
2
2.5
2
3.3V
IN
2.5
2
3.3V
IN
5V
5V
1.5
1
5V
IN
1.5
1
IN
1.5
1
*Using
IN
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
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
3.5
MAX. OUTPUT CURRENT (A)
3
Max. Continuous Current
vs. Ambient Temp 1.0V
OUT
*
2.5
2
3.3V
IN
5V
1.5
1
*Using
IN
0.5
layout (1oz copper)
0
60 70 80 90 100 110 120
AMBIENT TEMPERATURE (°C)
and B.O.M.
recommended
September 2005
5
M9999-092905
www.micrel.com
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