MIC22950
10A Integrated Switch Synchronous
Buck Regulator with Frequency
Programmable to 2MHz
General Description
The Micrel MIC22950 is a high-efficiency 10A integrated
switch, synchronous buck (step-down) regulator. The
MIC22950 switching frequency is programmable from
400kHz to 2MHz, allowing the customer to optimize
designing either for efficiency or for the smallest footprint.
The MIC22950 achieves over 95% efficiency while still
switching at 2MHz over a broad load range.
The ultra-high-speed control loop keeps the output voltage
within regulation, even under extreme transient load
swings commonly found in FPGAs and low voltage ASICs.
The output voltage can be adjusted down to 0.7V in order
to address all low-voltage power needs.
The MIC22950 features a full range of sequencing and
tracking options. The EN/DLY and the DELAY pins,
combined with the POR/PG pin, allow multiple outputs to
be sequenced in several ways during turn-on and turn-off
by using EN pin. The RC (Ramp Control™) pin allows the
device to be connected to any another device in the
MIC22x00 family of products, to keep the output voltages
within a certain delta V during start-up.
The MIC22950 is available in a 32-pin 5mm x 5mm MLF
®
with a junction operating range from
−40°C
to
+125°C.
Datasheet and supporting documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2.6V to 5.5V supply voltage
Fully-integrated MOSFET switches
Adjustable output voltage option down to 0.7V
Output load current up to 10A
Full sequencing and tracking capability
Power-On Reset
Efficiency >95% across a broad load range
Operating frequency programmable: 400kHz to 2MHz
Ultra-fast transient response
100% maximum duty cycle
Micropower shutdown
Thermal-shutdown and current-limit protection
Available in a 32-pin 5mm x 5mm MLF
®
package
−40°C
to
+125°C
junction temperature range
Applications
•
•
•
•
•
High-power density point-of-load conversion
Base stations, Servers and Routers
Blu-ray players, DVD Recorders
Computer Peripherals
FPGAs, DSP, and low-voltage ASIC power
_________________________________________________________________________________________________________________________
Typical Application
Efficiency vs. Load Current
100
95
EFFICIENCY (%)
90
85
80
75
70
65
60
0
2
4
6
V
IN
= 5V
V
OUT
= 3.3V
T
A
= 25°C
8
10
LOAD CURRENT (A)
MIC22950 10A Synchronous DC-DC Converter
Ramp Control is a trademark of Micrel, Inc
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Sequencing and Tracking
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
February 2010
M9999-021910-B
Micrel, Inc.
MIC22950
Ordering Information
Part Number
MIC22950YML
Nominal Output Voltage
Adjustable
Temperature Range
−40°
to
+125°C
Package
32-Pin 5mm x 5mm MLF
®
Lead Finish
Lead Free
Note:
®
MLF is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
32-Pin 5mm x 5mm MLF
®
(ML)
Pin Description
Pin Number
1,2,7,8,17,23,24
3
Pin Name
PVIN
EN/DLY
Pin Function
Power Supply Voltage (Input): Requires bypass capacitor to PGND.
Enable/ delay (Input): This pin has a 1.24V band gap reference. When the pin is pulled higher
that this the part will start up. Below this voltage the device is in its low quiescent current mode.
The pin has a 1µA current source pull-up to VIN. By adding a capacitor to this pin, a delay may
be generated. The enable function will not operate with an input voltage lower than UVLO.
Delay (Input): A capacitor sets the internal delay timer. Timer delays power-on reset (POR) at
power-up and power-down.
Ramp Control (Input): Capacitor-to-ground from this pin determines slew rate of output voltage
during start-up. This can be used for tracking capability as well as soft start. RC pin cannot be
left floating. Use a minimum capacitor value of 120pF or larger.
Power-On-Reset (Output): Open-drain output device indicates when the output is out of
regulation and is active after the delay set by the DELAY pin.
Power Ground (Power): Power Ground.
Switch (Output): Internal power MOSFET output switches.
Signal Ground (Signal): Signal Ground.
Frequency Set (Input): Adjustable Frequency with external capacitor.
Feedback (Input): Input to the error amplifier, connect to the external resistor divider network to
set the output voltage.
Compensation pin (Input): Place a RC-to-SGND to compensate the device, see applications
section.
Signal Power Supply Voltage (Input): Requires bypass capacitor-to-SGND.
Center Tab (Power): Must make a full connection to a GND plane for full output power to be
realized.
4
5
6
9,10,15,16,25,26,
31,32
11,12,13,14,27,
28,29,30
18
19
20
21
22
EP
DELAY
RC
POR/PG
PGND
SW
SGND
CF
FB
COMP
SVIN
GND
February 2010
2
M9999-021910-B
Micrel, Inc.
MIC22950
Absolute Maximum Ratings
(1)
Supply Voltage (
PVIN, SVIN
)..............................
−0.3V
to
+6V
Output Switch Voltage (V
SW
) ...........................
−0.3V
to
+6V
Output Switch Current (I
SW
) ......................Internally Limited
Logic Input Voltage (V
EN
, V
POR,
V
DLY
)................. –0.3V to V
IN
Control Voltage (
CF, RC, COMP, FB
) .................... –0.3V to V
IN
Lead Temperature (soldering, 10sec.)....................... 260°C
Storage Temperature (Ts).........................–65°C to +150°C
Operating Ratings
(2)
Supply Voltage (V
IN
)......................................... 2.6V to 5.5V
Junction Temperature (T
J
) ..................–40°C
≤
T
J
≤
+125°C
Thermal Resistance
MLF
®
(θ
JC
)..........................................................11°C/W
MLF
®
(θ
JA
)..........................................................30°C/W
Electrical Characteristics
(3)
T
A
= 25°C with V
IN
= V
EN
= 3.3V; V
OUT
= 1.8V, unless otherwise specified.
Bold
values indicate –40°C
≤
T
J
≤
+125°C.
Parameter
Supply Voltage Range
V
IN
Turn On Voltage Threshold
UVLO Hysteresis
Quiescent Current (PWM Mode)
Shutdown Current
[Adjustable] Feedback Voltage
FB pin input current
Current Limit
Output Voltage Line Regulation
Output Voltage Load Regulation
Maximum Duty Cycle
Switch ON-Resistance PFET
Switch ON-Resistance NFET
Oscillator Frequency
EN/DLY threshold voltage
EN/DLY source current
RC Pin I
RAMP
Power On Reset I
PG(LEAK)
V
IN
= 2.6 to V
IN
= 5.5V
Ramp Control Current
V
PORH
= 5.5V; POR = High
Output Logic-Low Voltage (undervoltage condition),
Power On Reset V
PG(LO)
Power On Reset V
PG
Over-temperature Shutdown
Over-temperature Shutdown 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.
Condition
Min.
2.6
Typ.
Max.
5.5
Units
V
V
mV
mA
µA
V
nA
A
%
%
%
mΩ
mΩ
(V
IN
Rising)
V
EN
= >1.34V; V
FB
= 1.1*V
NOM
(not switching)
V
EN
= 0V
±
2% (over temperature)
V
FB
= 0.9*V
NOM
V
OUT
1.8V; V
IN
= 2.6 to 5.5V, I
LOAD
= 100mA
100mA < I
LOAD
< 10A, Vin = 3.3V
V
FB
≤
0.5V
I
SW
= 1000mA V
FB
=0.5V
I
SW
= -1000mA V
FB
=0.9V
CF = 390pF
2.35
2.5
260
1
5
2.6
2
10
0.714
0.686
1
10
16.5
0.2
0.2
100
11
8
325
1.14
0.6
0.6
510
1.24
1
1
21
610
1.34
1.8
1.8
1
2
kHz
V
µA
µA
µA
µA
mV
%
I
POR
= 5mA
Hysteresis
Threshold, % of V
OUT
below nominal
7.5
77
2
10
160
20
12.5
%
°C
°C
February 2010
3
M9999-021910-B
Micrel, Inc.
MIC22950
Typical Characteristics
Shutdown Current
vs. Input Voltage
7
SHUTDOWN CURRENT (µA)
6
5
4
3
2
1
0
2
3
4
5
INPUT VOLTAGE (V)
6
INPUT CURRENT (µA)
10
OPERATING CURRENT (mA)
Shutdown Current
vs. Temperature
1.2
1
0.8
0.6
0.4
0.2
0
Operating Current (no SW)
vs. Input Voltage
9
8
7
6
5
4
3
2
1
0
-40
-20
0
20 40 60 80
TEMPERATURE (°C)
100 120
T
A
= 25°C
V
IN
= 3.3V
T
A
= 25°C
2
3
4
5
INPUT VOLTAGE (V)
6
Input Current (no SW)
vs. Temperature
0.9
REFERENCE VOLTAGE (V)
0.88
INPUT CURRENT (mA)
0.86
0.84
0.82
0.8
0.78
0.76
0.74
-40
-20
0
20 40 60 80
TEMPERATURE (°C)
100 120
0.708
0.706
0.704
0.702
0.7
0.698
0.696
0.694
0.692
2
Reference Voltage
vs. Input Voltage
0.708
REFERENCE VOLTAGE (V)
0.706
0.704
0.702
0.7
0.698
0.696
0.694
0.692
3
4
5
INPUT VOLTAGE (V)
6
-40 -20
Reference Voltage
vs. Temperature
T
A
= 25°C
0
20 40 60 80 100 120
TEMPERATURE (°C)
Enable Threshold
vs. Input Voltage
1.26
1.255
ENABLE VOLTAGE (V)
ENABLE VOLTAGE (V)
Enable Threshold
vs. Temperature
1.26
1.255
650
600
Switching Frequency
vs. Temperature
Enable (ON)
1.245
1.24
1.235
1.23
1.225
1.22
2.5
3
3.5
4
4.5
INPUT VOLTAGE (V)
5
5.5
1.245
1.24
1.235
1.23
1.225
1.22
-40 -20
0
Enable (ON)
FREQUENCY (kHz)
1.25
1.25
550
500
450
400
350
300
-40 -20
0
20 40 60 80
TEMPERATURE (°C)
100 120
T
A
= 25°C
V
IN
= 3.3V
CF = 390pF
20
40
60
80 100 120
TEM PERATURE (°C)
February 2010
4
M9999-021910-B
Micrel, Inc.
MIC22950
Typical Characteristics (Continued)
Switching Frequency
vs. Input Voltage
650
600
FREQUENCY (kHz)
550
500
450
400
350
300
2.5
3
3.5
4
4.5
INPUT VOLTAGE (V)
5
5.5
INPUT VOLTAGE (V)
2.8
2.7
Input Voltage UVLO
vs. Temperature
18
16
RDSon
vs. Temperature
RDS
ON
(P-Channel)
V
IN
= (ON)
RDSon (m
Ω
)
2.6
2.5
2.4
2.3
2.2
-40
-20
0
20
40
60
80
TEM PETATURE (°C)
100
120
14
12
10
8
6
4
2
0
-40
CF = 390pF
V
IN
= (OFF)
RDS
ON
(N-Channel)
-20
0
20 40 60 80
TEMPETATURE (°C)
100 120
RDSon
vs. Input Voltage
16
14
12
RDSon (m
Ω
)
10
8
6
4
2
0
2
3
4
5
INPUT VOLTAGE (V)
6
OUTPUT VOLTAGE (mV)
2000
1800
Output Voltage
vs. RC Voltage
100
95
90
EFFICIENCY (%)
85
80
75
70
65
60
0
200
400
600
800
RC VOLTAGE (mV)
1000
Efficiency vs. Load Current
(V
OUT
=1.2V)
V
IN
= 3.6V
RDS
ON
(P-Channel)
1600
1400
1200
1000
800
600
400
200
0
V
IN
= 2.6V
RDS
ON
(N-Channel)
V
IN
= 5V
T
CASE
= 25°C
T
CASE
= 25°C
V
OUT(NOM)
= 1.8V
0
2
4
6
8
LOAD CURRENT (A)
10
100
95
90
EFFICIENCY (%)
85
80
75
70
65
60
Efficiency vs. Load Current
(V
OUT
=1.8V)
100
95
EFFICIENCY (%)
Efficiency vs. Load Current
(V
OUT
=3.3V)
V
IN
= 3.6V
V
IN
= 2.6V
V
IN
= 5V
T
CASE
= 25°C
90
85
80
75
70
65
60
V
IN
= 5V
T
CASE
= 25°C
0
2
4
6
8
LOAD CURRENT (A)
10
0
2
4
6
8
LOAD CURRENT (A)
10
February 2010
5
M9999-021910-B
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