MIC4950
Hyper Speed Control™ 5A Buck Regulator
General Description
The MIC4950 is a high-efficiency, 5A synchronous buck
regulator with ultra-fast transient response. It is perfectly
suited for supplying processor core and I/O voltages from
a 5V or 3.3V bus. The MIC4950 provides a switching
frequency up to 3.3MHz while achieving peak efficiencies
up to 95%. An additional benefit of high-frequency
operation is very low output ripple voltage throughout the
entire load range with the use of a small output capacitor.
The MIC4950 is designed for use with a very small
inductor, down to 1µH, and an output ceramic capacitor as
small as 10µF, without the need for external ripple
injection. A wide range of output capacitor types and
values can also be accommodated.
The MIC4950 supports safe start-up into a pre-biased
output, and offers short-circuit and thermal shutdown
protections.
The MIC4950 is available in 8-Pin SOIC and 10-Pin 3mm
× 4mm DFN packages with an operating junction
temperature range from –40°C to +125°C.
Datasheets and support documentation are available on
Micrel’s web site at:
www.micrel.com.
Features
Input voltage: 2.7V to 5.5V
5A output current
Up to 95% efficiency
Up to 3.3MHz operation
Safe start-up into a pre-biased output
Power Good output
Ultra-fast transient response
Low output voltage ripple
Low R
DSON
integrated MOSFET switches
0.01µA shutdown current
Thermal shutdown and current limit protection
Output voltage as low as 0.7V
8-Pin SOIC and 3mm × 4mm DFN-10L
–40°C to +125°C junction temperature range
Applications
DTVs
Set-top boxes
Printers
DVD players
Distributed power supplies
Typical Application
Hyper Speed Control 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
March 20, 2014
Revision 1.1
Micrel, Inc.
MIC4950
Ordering Information
Part Number
(1)
Top Mark
4950YFM
MIC4950
Temperature Range
–40°C ≤ T
J
≤ +125°C
–40°C ≤ T
J
≤ +125°C
Package
8-pin SOIC
10-pin 3mm x 4mm DFN
(2)
Lead Finish
Pb-Free
Pb-Free
MIC4950YFM
MIC4950YFL
Note:
1. Other options are available. Contact Micrel for details.
2. DFN is GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
8-Pin SOIC (FM)
(Top View)
3mm x 4mm DFN (FL)
(Top View)
Pin Description
Pin Number
SOIC-8 (YFM)
1
2
Pin Number
DFN-10 (YFL)
1, 2, EP
3, 8
Pin Name
PGND
PVIN
Pin Function
Power Ground.
Power Input Voltage: Connect a 10µF ceramic capacitor between PVIN and
PGND for input decoupling. Pins 3 and 8 are internally connected in the
DFN-10 package.
Analog Input Voltage: Connect a 1µF ceramic capacitor between AVIN and
AGND to decouple the noise from the internal reference and error comparator.
Analog Ground Input: Connect to a quiet ground plane for best operation. Do
not route power switching currents on the AGND net. Connect AGND and
PGND nets together at a single point.
Feedback (Input): Connect an external divider between VOUT and AGND
(Analog Ground) to program the output voltage.
Power Good (Output): Open-drain output. A pull-up resistor from this pin to a
voltage source is required to detect an output power-is-good condition.
Enable (Input): Logic high enables operation of the regulator. Logic low shuts
down the device. Do not leave floating.
Switch (Output): Internal power MOSFET output switches.
3
4
4
5
AVIN
AGND
5
6
7
8
6
7
9
10
FB
PG
EN
SW
March 20, 2014
2
Revision 1.1
Micrel, Inc.
MIC4950
Absolute Maximum Ratings
(3)
PVIN, AVIN Supply Voltage (V
IN
) ...................... –0.3V to 6V
SW Output Switch Voltage (V
SW
) ...................... –0.3V to V
IN
EN, PG (V
EN
, V
PG
) ............................................. –0.3V to V
IN
FB Feedback Input Voltage (V
FB
) ...................... –0.3V to V
IN
Storage Temperature Range .................... –65°C to +150°C
(5)
ESD Rating ........................................................ 2kV, HBM
Operating Ratings
(4)
Supply Voltage (V
IN
) ......................................... 2.7V to 5.5V
Enable Input Voltage (V
EN
) .................................... 0V to VIN
Junction Temperature Range (T
J
).......–40°C ≤ T
J
≤ +125°C
Thermal Resistance
SOIC-8 (
JA
) ..................................................... 120°C/W
DFN-10 (
JA
) ...................................................... 35°C/W
Electrical Characteristics
(6)
V
IN
= V
EN
= 3.3V; L = 1.0µH; C
IN
= 10µF; C
OUT
= 10µF; T
A
= 25°C,
bold
values indicate –40°C≤ T
J
≤ +125°C, unless noted.
Symbol
V
IN
V
UVLO
V
UVLOH
I
Q
I
SD
V
FB
I
LIMIT
LINEREG
Parameter
Supply Voltage Range
Under-Voltage Lockout
Threshold
Under-Voltage Lockout
Hysteresis
Quiescent Current
Shutdown Current
Feedback Voltage
Current Limit
Output Voltage Line
Regulation
FB = 0.9*V
FB (Nominal)
V
IN
= 2.7 to 3.5V, V
OUTNOM
= 1.8V, I
LOAD
= 20mA
V
IN
= 4.5V to 5.5V if V
OUTNOM
≥ 2.5V, I
LOAD
=
20mA
20mA < I
LOAD
< 500mA,
V
IN
= 3.6V if V
OUTNOM
< 2.5V
LOADREG
Output Voltage Load
Regulation
20mA < I
LOAD
< 500mA,
V
IN
= 5.0V if V
OUTNOM
≥ 2.5V
20mA < I
LOAD
< 5A, V
IN
= 3.6V if V
OUTNOM
< 2.5V
20mA < I
LOAD
< 5A, V
IN
= 5.0V if V
OUTNOM
≥ 2.5V
R
DSON-P
R
DSON-N
PWM Switch ON-Resistance
I
SW
= 1A P-Channel MOSFET
I
SW
= –1A N-Channel MOSFET
V
IN
= 4.5V, V
FB
= 0.5V
t
ON
Maximum Turn-On Time
V
IN
= 3.0V, V
FB
= 0.5V
V
IN
= 2.7V, V
FB
= 0.5V
t
OFF
t
SOFT-ON
V
EN
Notes:
3. Exceeding the absolute maximum ratings may damage the device.
4. The device is not guaranteed to function outside its operating ratings.
5. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
6. Specification for packaged product only.
Condition
Min.
2.7
Typ.
Max.
5.5
Units
V
V
mV
Turn-On
2.41
2.5
400
2.61
I
OUT
= 0mA , FB > 1.2*V
FB (Nominal)
V
EN
= 0V
0.609
5.5
0.8
0.01
0.625
7.5
1
2
2
0.64
10
mA
µA
V
A
%/V
0.3
%
1
30
25
665
1000
1120
176
500
0.5
0.8
1.2
%
Ω
ns
Minimum Turn-Off Time
Soft Start Time
Enable Threshold
V
IN
= 3.0V, V
FB
= 0.5V
V
OUT
= 90% of V
OUTNOM
Turn-On
ns
µs
V
March 20, 2014
3
Revision 1.1
Micrel, Inc.
MIC4950
Electrical Characteristics
(6)
(Continued)
Symbol
I
EN
V
OUTPG
V
OUTPGH
T
SD
T
SDH
Parameter
Enable Input Current
Power Good Threshold
Power Good Hysteresis
Overtemperature Shutdown
Overtemperature Shutdown
Hysteresis
Rising
82
Condition
Min.
Typ.
0.1
88
7
150
20
Max.
1
94
Units
µA
%
%
C
C
March 20, 2014
4
Revision 1.1
Micrel, Inc.
MIC4950
Typical Characteristics
Efficiency
vs. Output Current
100
95
90
V
IN
= 5V
V
OUT
= 3.3V
100
95
90
V
IN
= 3.3V
V
OUT
= 1.8V
Efficiency
vs. Output Current
100
95
90
Efficiency
vs. Output Current
V
IN
= 3.3V
V
OUT
= 1.2V
EFFICIENCY (%)
85
80
75
70
65
60
0
1
EFFICIENCY (%)
85
80
75
70
65
60
V
IN
= 5.0V
V
OUT
= 1.8V
EFFICIENCY (%)
85
80
75
70
65
60
V
IN
= 5V
V
OUT
= 1.2V
2
3
4
5
0
1
2
3
4
5
0
1
2
3
4
5
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
Current Limit
vs. Input Voltage
12
Current Limit
vs. Feedback Voltage
12
3.0
Line Regulation
vs. Input Voltage
10
LINE REGULATION (%/V)
10
CURRENT LIMIT (A)
CURRENT LIMIT (A)
2.0
8
8
6
1.0
6
4
2
0
V
IN
= 5V
V
OUT
= 1.8V
0.0
I
OUT
= 0A
-1.0
4
V
OUT
= 1.8V
2
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0.0
0.1
0.2
0.3
0.4
0.5
-2.0
2.7
3.0
3.3
3.6
INPUT VOLTAGE (V)
FEEDBACK VOLTAGE (V)
INPUT VOLTAGE (V)
Line Regulation
vs. Input Voltage
3
3
Line Regulation
vs. Input Voltage
3
Line Regulation
vs. Input Voltage
LINE REGULATION (%/V)
2
LINE REGULATION (%/V)
LINE REGULATION (%/V)
2
2
1
1
1
0
0
0
-1
V
OUT
= 1.8V
I
OUT
= 0A
-1
V
OUT
= 1.8V
I
OUT
= 1A
-1
V
OUT
= 1.8V
I
OUT
= 1A
-2
4.50
-2
4.75
5.00
5.25
5.50
2.7
3.0
3.3
3.6
-2
4.50
4.75
5.00
5.25
5.50
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
March 20, 2014
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Revision 1.1
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