MIC4723
3A 2MHz Integrated Switch
Buck Regulator
General Description
The Micrel MIC4723 is a high efficiency PWM buck (step-
down) regulator that provides up to 3A of output current.
The MIC4723 operates at 2.0MHz and has proprietary
internal compensation that allows a closed loop bandwidth
of over 200KHz.
The low on-resistance internal p-channel MOSFET of the
MIC4723 allows efficiencies over 92%, reduces external
components count and eliminates the need for an
expensive current sense resistor.
The MIC4723 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 MIC4723 is available in the exposed pad 12-pin
3mm x 3mm MLF
®
and 10-pin ePAD MSOP packages with
a junction operating range from –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2.7/3.0V to 5.5V supply voltage
2.0MHz PWM mode
Output current to 3A
Up to 94% efficiency
100% maximum duty cycle
Adjustable output voltage option down to 1V
Ultra-fast transient response
Ultra-small external components
Stable with a 1µH inductor and a 4.7µF output
capacitor
Fully integrated 3A MOSFET switch
Micropower shutdown
Thermal shutdown and current limit protection
Pb-free 12-pin 3mm x 3mm MLF
®
package
Pb-free 10-pin ePAD MSOP package
–40°C to +125°C junction temperature range
Applications
•
FPGA/DSP/ASIC applications
•
General point of load
•
Broadband communications
•
DVD/TV recorders
•
Point of sale
•
Printers/Scanners
•
Set top boxes
•
Computing peripherals
•
Video cards
___________________________________________________________________________________________________________
Typical Application
96
94
92
90
88
86
84
82
80
MIC4723
3.3V
OUT
Efficiency
4.5V
IN
5V
IN
5.5V
IN
3A 2MHz Buck Regulator
78
76
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
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
June 2008
M9999-060308-E
Micrel, Inc.
MIC4723
Ordering Information
Part Number
MIC4723YML
MIC4723YMME
Note
MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
®
Voltage
Adj.
Adj.
Temperature Range
–40° to +125°C
–40° to +125°C
Package
12-Pin 3x3 MLF
®
10-Pin ePAD MSOP
Lead Finish
Pb-Free
Pb-Free
Pin Configuration
SW 1
VIN 2
PGND 3
SGND 4
BIAS 5
FB 6
EP
12 SW
11 VIN
10 NC
9 PGOOD
8 EN
7 NC
SW
VIN
SGND
BIAS
FB
1
2
3
4
5
EP
10 SW
9
8
7
6
VIN
PGND
PGOOD
EN
12-Pin 3mm x 3mm MLF (ML)
10-Pin ePAD MSOP (MME)
Pin Description
Pin Number
MLF-12
Pin Number
MSOP-10
Pin Name
Pin Function
1, 12
2, 11
3
4
5
6
7, 10
8
9
EP
1, 10
2, 9
8
3
4
5
—
SW
VIN
PGND
SGND
BIAS
FB
NC
EN
PGOOD
GND
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 (Analog) 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.
No Connect. Not internally connected to die. This pin can be tied to any other pin if
desired.
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.
6
7
EP
June 2008
2
M9999-060308-E
Micrel, Inc.
MIC4723
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .......................................................+6V
Output Switch Voltage (V
SW
) ..........................................+6V
Output Switch Current (I
SW
)............................................11A
Logic Input Voltage (V
EN
) .................................. –0.3V to V
IN
Storage Temperature (T
s
) .........................–60°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +2.7V to +5.5V
Logic Input Voltage (V
EN
) ....................................... 0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
3mm x 3mm MLF-12 (θ
JA
) .................................60°C/W
3mm x 3mm MLF-12 (θ
Jc
) .................................28°C/W
ePAD MSOP-10 (θ
JA
) ........................................76°C/W
ePAD MSOP-10 (θ
Jc
) ........................................28°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
Condition
Min
Typ
Max
5.5
5.5
Units
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
Maximum Duty Cycle
PWM Switch ON-
Resistance
Oscillator Frequency
Enable Threshold
Enable Hysteresis
Enable Input Current
Power Good Range
Power Good Resistance
Over-Temperature
Shutdown
Over-Temperature
Hysteresis
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Specification for packaged product only.
MIC4723YML
MIC4723YMME
(turn-on)
2.7
3.0
2.45
V
V
V
mV
2.55
100
2.65
V
FB
= 0.9 * V
NOM
(not switching)
V
EN
= 0V
±
2% (over temperature) I
LOAD
= 100mA
0.98
570
2
900
10
1.02
µA
µA
V
nA
A
%
%
%
%
1
V
FB
= 0.9 * V
NOM
V
OUT
> 2V; V
IN
= V
OUT
+500mV to 5.5V; I
LOAD
= 100mA
V
OUT
< 2V; V
IN
= 2.7V to 5.5V; I
LOAD
= 100mA
20mA < I
LOAD
< 3A
V
FB
≤
0.4V
I
SW
= 50mA; V
FB
= GND (High Side Switch)
1.8
0.5
100
3.5
5
0.07
0.2
95
2
0.85
50
0.1
±7
200
300
2.2
1.3
2.3
mΩ
mΩ
MHz
V
mV
µA
%
Ω
°
C
°
C
±10
250
I
PGOOD
= 500µA
150
160
25
June 2008
3
M9999-060308-E
Micrel, Inc.
MIC4723
Typical Characteristics
96
4.5V
IN
94
92
90
88
86
84
82
80
78
76
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
5.5V
IN
MIC4723
3.3V
OUT
Efficiency
5V
IN
94
92
90
88
86
84
82
80
0
MIC4723
2.5V
OUT
Efficiency
4.5V
IN
5V
IN
100
98
96
94
92
90
88
86
84
82
80
0
MIC4723
2.5V
OUT
Efficiency
3V
IN
3.3V
IN
5.5V
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
90
88 4.5V
IN
5V
IN
86
84
82
80
5.5V
IN
78
76
74
72
70
68
66
64
62
60
0.5
1
1.5
2
2.5
0
OUTPUT CURRENT (A)
MIC4723
1.8V
OUT
Efficiency
3
96
94
92 3V
IN
3.3V
IN
90
88
86
84
3.6V
IN
82
80
78
76
74
72
70
68
66
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
MIC4723
1.8V
OUT
Efficiency
3
86
84
82
80
78
76
74
72
70
68
66
64
0
MIC4723
1.5V
OUT
Efficiency
4.5V
IN
5V
IN
5.5V
IN
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
92
90
3V
IN
88
3.3V
IN
86
84
82
3.6V
IN
80
78
76
74
72
70
68
66
64
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
MIC4723
1.5V
OUT
Efficiency
3
90
88
86
84
82
80
78
76
74
72
70
68
66
64
62
60
0
MIC4723
1.2V
OUT
Efficiency
4.5V
IN
5V
IN
5.5V
IN
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
90
88
86 3V
IN
84
3.3V
IN
82
80
78
76
3.6V
IN
74
72
70
68
66
64
62
60
0.5
1
1.5
2
2.5
0
OUTPUT CURRENT (A)
MIC4723
1.2V
OUT
Efficiency
3
78
76
74
72
70
68
66
64
62
60
0
MIC4723
1V
OUT
Efficiency
4.5V
IN
5V
IN
84
82
80
78
76
74
72
70
68
66
MIC4723
1V
OUT
Efficiency
OUTPUT VOLTAGE (V)
Load Regulation
1.010
3V
IN
3.3V
IN
1.005
5.5V
IN
3.6V
IN
1.000
0.995
3.3V
V
IN
= 3.3V
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
64
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
0.990
0
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
3
June 2008
4
M9999-060308-E
Micrel, Inc.
MIC4723
Typical Characteristics (continue)
1.0010
1.0008
1.0006
1.0004
1.0002
1.0000
0.9998
0.9996
0.9994
0.9992
0.9990
2.7
3.2 3.7 4.2 4.7 5.2
SUPPLY VOLTAGE (V)
Line Regulation
1.010
1.008
1.006
1.004
1.002
1.000
0.998
0.996
Feedback Voltage
vs. Temperature
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
Frequency
vs. Temperature
0.994
0.992 V = 3.3V
IN
0.990
20 40 60 80
TEMPERATURE (°C)
1.6 V = 3.3V
IN
1.5
20 40 60 80
TEMPERATURE (°C)
1.2
1.0
0.8
0.6
0.4
0.2
Feedback Voltage
vs. Supply Voltage
800
700
600
500
400
300
200
Quiescent Current
vs. Supply Voltage
120
115
110
105
100
95
90
85
80
R
DSON
vs. Supply Voltage
V
EN
= V
IN
0
0
1
2
3
4
5
SUPPLY VOLTAGE (V)
100
0
0
V
EN
= V
IN
1
2
3
4
5
SUPPLY VOLTAGE (V)
6
75
70
2.7
3.2 3.7 4.2 4.7 5.2
SUPPLY VOLTAGE (V)
160
140
120
100
80
60
40
20
0
R
DSON
vs. Temperature
1.2
1.0
0.8
0.6
0.4
0.2
Enable Threshold
vs. Supply Voltage
1.2
1.0
0.8
0.6
0.4
0.2
Enable Threshold
vs. Temperature
V
IN
= 3.3V
20 40 60 80
TEMPERATURE (°C)
0
2.7
3.2
3.7
4.2
4.7
SUPPLY VOLTAGE (V)
0
V
IN
= 3.3V
20 40 60 80
TEMPERATURE (°C)
June 2008
5
M9999-060308-E
PCB Design
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