MIC2267
Input Current Limiting
Synchronous Buck Regulator
USB Power Maximizer™
General Description
The MIC2267 is a USB Power Maximizer™ which
transfers the maximum power from the limited USB current
source by shaping the input current limit profile. It
incorporates a high efficiency, integrated synchronous step
down regulator. Internal 150mΩ switches and adjustable
operating frequency allows the MIC2267 to achieve
greater than 90% efficiency across a broad load range. It
replaces the USB current limit switch, 5V buck regulator
and minimizes capacitance for many USB applications.
The adjustable frequency control can be utilized to move
harmonics away from sensitive frequency bands.
The MIC2267 allows the input current limit profile to be
shaped for various applications. With a current mode
control with external compensation, the MIC2267 transient
response can be optimized over load and output
capacitance making it highly flexible for many applications.
Additional features include 1µA shutdown current, output
current limit and thermal shutdown protection. The
MIC2267 is available in a 12-pin 3mm x 3mm MLF
®
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
•
•
•
•
•
•
•
•
•
•
•
•
•
Input voltage range: 3.0V to 5.5V
Output voltage adjustable down to 1.0V
Up to 96% efficiency at 500mA output
Efficiency >90% across a broad load range
Fast transient response
Adjustable frequency from 400kHz to 1.5MHz
Adjustable input current limiting 100mA to over 1A
100% maximum duty cycle
Fully integrated MOSFET switches
Micropower shutdown
Thermal shutdown and output current limit protection
12-pin 3mm x 3mm MLF
®
Junction temperature range:
−40°C
to +125°C
Applications
•
USB power
•
Wireless router cards
•
General buck converter applications
_______________________________________________________________________________________________________
Typical Application
Efficiency vs.
Output Current
100
95
90
EFFICIENCY (%)
85
80
75
70
65
60
55
50
0
0.5
1
1.5
2
OUTPUT CURRENT (A)
V
OUT
= 3.3V
V
IN
= 5.5V
V
IN
= 4.2V
MIC2267 USB Input Current Limiting Synchronous Buck Regulator
Efficiency 5V
IN
to 3.3V
OUT
USB Power Maximizer is a trademark of Micrel, 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
January 2011
M9999-011711-A
Micrel Inc.
MIC2267
Ordering Information
Part Number
MIC2267YML
Note:
1. Package is GREEN RoHS compliant. Lead finish is NiPdAu. Mold compound is halogen free.
Voltage
Adjustable
Mark Code
2267
Temperature Range
–40°C to +125°C
Package
(1)
12-Pin 3mm x 3mm MLF
®
Pin Configuration
12-Pin 3mm x 3mm MLF
®
(ML)
(Top View)
Pin Description
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
ePAD
Pin Name
AGND
FB
COMP
PGOOD
SW
PGND
VIN
EN
FILTER
LIMIT
SLOPEC
FREQ
HS Pad
Pin Function
Analog Ground: The ground return for the low power blocks of the MIC2267.
Feedback (Input): Input to the error amplifier. Connect a resistor divider between VOUT and
ground to adjust the output voltage.
Compensation Pin: Output of the internal gm error amplifier. Place a series connected,
Resistor and Capacitor to GND for external compensation.
Power Good (Output): Open drain of an N-Channel MOSFET. Connect a resistor to VIN or
VOUT for power good signalling.
Switch (Output): Internal power MOSFET output switches.
Power Ground: The ground return for the switching currents.
Power Supply Voltage (Input): Requires bypass capacitor to GND
Enable/Delay (Input): Apply a Logic High to start the device. Apply Logic Low to stop the
device; placing it in a low quiescent current mode.
Input Current Limit Filter: Place a capacitor to VIN to adjust the time constant for the input
current limit filter.
Input Current Limit: Place a resistor to ground to adjust the average current limit from the input
supply.
Slope Compensation: Sets current mode slope compensation
Frequency Control: The switching frequency is adjusted from 400kHz to 1.5MHz with a resistor
from this pin to ground.
Exposed Heatsink Pad: Thermal connection between die and external ground plane. A solid
connection to a large ground plane is required for full output power. This pad must be
connected to ground.
January 2011
2
M9999-011711-A
Micrel Inc.
MIC2267
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ........................................
−0.3V
to +6V
Output Switch Voltage (V
SW
) ...........................
−0.3V
to +6V
Power Good Voltage (V
PGOOD
) ........................
−0.3V
to +6V
Enable Input Voltage (V
EN
)................................
−0.3V
to V
IN
Feedback Voltage (V
FB
) ....................................
−0.3V
to V
IN
AGND to PGND Voltage ..............................
−0.3V
to +0.3V
Switch Current (I
SW
) .................................Internally Limited
Power Dissipation .....................................Internally Limited
Lead Temperature (soldering, 10sec.)....................... 260°C
Storage Temperature (T
s
) .........................−65°C to +150°C
ESD Human Body Model Rating
(3)
................................ 2kV
ESD Machine Model Rating
(3)
.....................................200V
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +3.0V to +5.5V
Power Good Voltage (V
PGOOD
) ......................... 0V to +5.5V
Enable Input Voltage (V
EN
) .................................... 0V to V
IN
Feedback Voltage (V
FB
) ........................................ 0V to V
IN
AGND to PGND Voltage ..............................
−0.3V
to +0.3V
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
3mm x 3mm MLF
®
-12(θ
JA
).................................61°C/W
3mm x 3mm MLF
®
-12(θ
JC
).................................27°C/W
Electrical Characteristics
(4)
V
IN
= V
EN
= 5.0V, V
OUT
= 3.3V, I
LOAD
= 10mA, C
IN
= 10µF, L = 4.7µH, C
OUT
= 47µF, R
FREQ
= 100kΩ; R
SLOPEC
= 100kΩ, R
LIM
= 100kΩ,
R
COMP
= 11.5kΩ, C
COMP
= 15nF, T
A
= 25°C;
bold
values indicate –40°C
≤
T
J
≤
125°C; unless noted.
Parameter
Power Input Supply
Input Voltage Range (V
IN
)
V
IN
UVLO Threshold
V
IN
UVLO Hysteresis
Quiescent Current
Shutdown Current
Reference Voltage
Feedback Voltage
Feedback Bias Current
Output Voltage Line Regulation
Output Voltage Load Regulation
Enable Control
Enable Logic High Threshold
Enable Logic Low Threshold
Input Current Limit
V
FB
= 0.5V, R
LIMIT
= 107kΩ
Input Current Limit
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.
Conditions
Min.
3.0
Typ.
Max.
5.5
Units
V
V
mV
mA
Rising
PWM Mode, V
EN
>
1.8V, V
FB
= 0.9V, I
OUT
= 0A
V
EN
= 0V
±2% over temperature
V
FB
= 1V
V
IN
= V
EN
= 4V to 5.5V, I
LOAD
= 100mA
100mA < I
LOAD
< 1.2A
2.75
2.9
320
1
1
3.0
5
1.02
µA
V
nA
%
%
0.98
1
1
0.2
0.2
1.2
1.8
V
V
0.4
0.5
0.7
1.1
1
0.7
1.1
1.6
0.9
1.5
2.1
V
FB
= 0.5V, R
LIMIT
= 68.1kΩ
V
FB
= 0.5V, R
LIMIT
= 46.4kΩ
A
January 2011
3
M9999-011711-A
Micrel Inc.
MIC2267
Electrical Characteristics
(4)
V
IN
= V
EN
= 5.0V, V
OUT
= 3.3V, I
LOAD
= 10mA, C
IN
= 10µF, L = 4.7µH, C
OUT
= 47µF, R
FREQ
= 100kΩ; R
SLOPEC
= 100kΩ, R
LIM
= 100kΩ,
R
COMP
= 11.5kΩ, C
COMP
= 15nF, T
A
= 25°C;
bold
values indicate –40°C
≤
T
J
≤
125°C; unless noted.
Parameter
Soft Start
Soft Start
Internal FETs
Top MOSFET RDS(ON)
Bottom MOSFET RDS(ON)
Oscillator/PWM
R
FREQ
= 250kΩ
Oscillator Frequency
Maximum Duty Cycle
Thermal Protection
Over Temperature Shutdown
Over Temperature Shutdown
Hysteresis
Power Good
Power Good Threshold
Power Good Output Low
Voltage
Power Good Leakage Current
Note:
4. Specification for packaged product only.
Conditions
Min.
Typ.
Adaptive
Max.
Units
I
SW
= 500mA, V
FB
= 0.9V
I
SW
= 500mA, V
FB
= 1.1V
0.32
0.8
1.2
100
136
100
0.4
1
1.5
225
225
0.48
1.2
1.8
mΩ
mΩ
R
FREQ
= 100kΩ
R
FREQ
= 60kΩ
V
FB
<
0.5V
MHz
%
160
20
°C
°C
V
OUT
Rising (V
OUT
% below nominal)
V
FB
= 0.9V, I
PGOOD
= 5mA
V
FB
= 1.0V, V
PGOOD
= 5.5V
6.5
10
130
12.5
200
1
2
%
mV
µA
January 2011
4
M9999-011711-A
Micrel Inc.
MIC2267
Typical Characteristics
Shutdown Current
vs. Input Voltage
100
SHUTDOWN CURRENT (nA)
SHUTDOWN CURRENT (nA)
500
V
EN
= 0V
T
AMB
= 25°C
Shutdown Current
vs. Temperature
10
SUPPLY CURRENT (mA)
V
EN
= 0V
V
IN
= 5V
Supply Current
vs. Input Voltage
9
8
7
6
5
4
3
2
1
0
V
EN
= 1.8V
T
AMB
= 25°C
F
SW
= 1MHz
90
80
70
60
50
40
30
20
10
0
2.5
3
3.5
4
4.5
450
400
350
300
250
200
150
100
50
0
-60 -40 -20
0
20
40
5
5.5
6
60
80 100
2.5
3
INPUT VOLTAGE (V)
TEMPERATURE (°C)
3.5
4
4.5
5
INPUT VOLTAGE (V)
5.5
6
Supply Current
vs. Temperature
10
Reference Voltage
vs. Input Voltage
1.020
REFERENCE VOLTAGE (V)
REFERENCE VOLTAGE (V)
1.020
1.015
1.010
1.005
1.000
0.995
0.990
0.985
Reference Voltage
vs. Temperature
SUPPLY CURRENT (mA)
9
8
7
6
5
4
3
2
1
0
-50 -30 -10 10
30 50
70 90 110 130
TEMPERATURE (°C)
V
EN
= 1.8V
V
IN
= 5V
F
SW
= 1MHz
1.015
1.010
1.005
1.000
0.995
0.990
0.985
0.980
2.5
3
3.5
4
4.5
5
5.5
6
INPUT VOLTAGE (V)
TAMB = 25°C
VIN = 5V
0.980
-50 -30 -10 10 30 50 70 90 110 130
TEMPERATURE (°C)
Enable Threshold
vs. Input Voltage
1.8
ENABLE THRESHOLD (V)
ENABLE THRESHOLD (V)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
Enable Threshold
vs. Temperature
SWITCHING FREQUENCY (kHz)
1200
1150
1100
1050
1000
950
900
850
800
Switching Frequency
vs. Temperature
1.6
1.4
1.2
1
0.8
0.6
0.4
2.5
3
3.5
4
4.5
5
5.5
6
INPUT VOLTAGE (V)
VEN HIGH
VEN LOW
VEN HIGH
VEN LOW
V
IN
= 5V
-50 -30 -10 10 30 50 70 90 110 130
TEMPERATURE (°C)
-50 -30 -10 10
30
50
70 90 110 130
TEMPERATURE (°C)
MOSFET RDS(ON)
vs. Input Voltage
180
160
140
RDS(ON) (mΩ)
120
100
80
60
40
20
0
2.5
3
3.5
4
4.5
5
5.5
6
INPUT VOLTAGE (V)
I
OUT
= 0.5A
T
AMB
= 25°C
PMOS RDSon
NMOS RDSon
MOSFET RDS(ON)
vs. Temperature
160
140
RDS(ON) (mΩ)
120
100
80
60
40
20
0
-50 -30 -10 10
30
50
70
90 110 130
I
OUT
= 0.5A
V
IN
= 5V
PMOS RDSon
NMOS RDSon
Output Voltage
vs. Output Current
3.320
3.315
OUTPUT VOLTAGE (V)
3.310
3.305
3.300
3.295
3.290
3.285
3.280
0
0.5
1
1.5
2
V
IN
= 5.5V
V
OUT
= 3.3V
TEMPERATURE (°C)
OUTPUT CURRENT (A)
January 2011
5
M9999-011711-A
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