MIC22400
4A Integrated Switch Synchronous
Buck Regulator with Frequency
Programmable up to 4MHz
General Description
The Micrel MIC22400 is a high efficiency 4A integrated
switch synchronous buck (step-down) regulator. The
MIC22400 is optimized for highest efficiency and achieves
over 90% efficiency while still switching at 1MHz 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 to address all low voltage power needs. A full
range of sequence options are available with the
MIC22400. The enable/delay pin combined with the power
good pin allows multiple outputs to be sequenced in any
way on turn on and turn off. The RC (Ramp Control™) pin
allows the device to be connected to another MIC22400
family of products to keep the output voltages within a
certain
∆V
on start up.
The MIC22400 is available in a 20-pin 3mm x 4mm MLF
®
and thermally enhanced 20-pin e-TSSOP 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
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Input voltage range: 2.6V to 5.5V
Output voltage adjustable down to 0.7V
Output current up to 4A
Full sequencing and tracking ability
Power on reset
Efficiency > 90% across a broad load range
Programmable frequency 800kHz to 4MHz
Easy RC compensation
Ultra fast transient response
100% maximum duty cycle
Fully integrated MOSFET switches
Micropower shutdown
Thermal shutdown and current limit protection
20-pin 3mm x 4mm MLF
®
20-pin e-TSSOP
–40°C to +125°C junction temperature range
Applications
•
•
•
•
•
•
High power density point of load conversion
Servers and routers
DVD recorders
Computing peripherals
Base stations
FPGAs, DSP and low voltage ASIC power
Typical Application
Efficiency V
O
= 3.3V
100
95
90
85
80
75
70
65
60
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
OUTPUT CURRENT (A)
MIC22400 4A Synchronous Buck Regulator
Ramp Control is a trademark of Micrel, Inc.
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Sequencing & 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 2008
M9999-022108-A
Micrel, Inc.
MIC22400
Ordering Information
Part Number
MIC22400YML
MIC22400YTSE*
Voltage
Adj.
Adj.
Junction Temp. Range
–40° to +125°C
–40° to +125°C
Package
20-Pin 3x4 MLF
®
20-Pin e-TSSOP
Lead Finish
Pb-Free
Pb-Free
*
Contact Micrel Marketing for YTSE availability.
Pin Configuration
DELAY
PVIN
RC
EN
EN
DELAY
1
2
3
4
5
6
7
8
9
20 PVIN
19 NC
18 PGND
17 SW
16 SW
15 SW
14 SW
13 PGND
12 NC
11 PVIN
POR
CF
NC
COMP
NC
FB
SVIN
SGND
PVIN
NC
PGND
SW
SW
SW
SW
PGND
RC
POR
CF
COMP
NC
FB
SGND
SVIN 10
20-Pin 3mm x 4mm MLF
®
(ML)
20-Pin e-TSSOP (TS)
February 2008
2
M9999-022108-A
Micrel, Inc.
MIC22400
Pin Description
Pin Number
MLF-20
1
2
3, 5, 9
4
6
7
8
10, 17
11, 16
12, 13, 14, 15
18
Pin Number
e-TSSOP-20
4
5
7, 12, 19
6
8
9
10
11, 20
13, 18
14, 15, 16, 17
1
Pin Name
POR
CF
NC
COMP
FB
SGND
SVIN
PVIN
PGND
SW
EN
Description
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.
Adjustable frequency with external capacitor.
Not connected internally.
Compensation pin (Input): Place a RC to GND to compensate the device, see
applications section.
Feedback: Input to the error amplifier, connect to the external resistor divider
network to set the output voltage.
Signal Ground (Signal): Ground
Signal Power Supply Voltage (Input): Requires bypass capacitor to GND.
Power Supply Voltage (Input): Requires bypass capacitor to GND.
Power Ground (Signal): Ground
Switch (Output): Internal power MOSFET output switches.
Enable (Input): When this pin is pulled higher than the enable threshold, the part
will start up. Below this voltage the device is in its low quiescent current mode.
The pin has a 1µA current source charging it to VIN. By adding a capacitor to this
pin a delay may easily be generated. The enable function will not operate with an
input voltage lower than the min specified.
Delay (Input): Capacitor-to-ground sets internal delay timer. Timer delays power-
on reset (POR) output at turn-on and ramp down at turn-off.
Ramp Control: 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.
Exposed Pad (Power): Must make a full connection to a GND plane for full output
power to be released.
19
20
2
3
DELAY
RC
EP
EP
GND
February 2008
3
M9999-022108-A
Micrel, Inc.
MIC22400
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .........................................................6V
Output Switch Voltage (V
SW
) ............................................6V
Output Switch Current (I
SW
)..............................................6A
Logic Input Voltage (V
EN
, V
LQ
)........................... V
IN
to –0.3V
Storage Temperature (T
s
) .........................–65°C to +150°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)......................................... 2.6V to 5.5V
Junction Temperature (T
J
) ..................–40°C
≤
T
J
≤
+125°C
Thermal Resistance
3x4 MLF-20 (θ
JA
) ...............................................45°C/W
e-TSSOP-20 (θ
JA
) ...........................................32.2°C/W
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
= V
EN
= 3.3V; V
OUT
= 1.2V, C
OSC
= 400pF, unless otherwise specified.
Bold
values indicate
–40°C< T
J
< +125°C.
Parameter
Supply Voltage Range
Under-Voltage Lockout Threshold
UVLO Hysteresis
Quiescent Current, PWM Mode
Shutdown Current
[Adjustable] Feedback Voltage
Oscillator Current
FB Pin Input Current
Current Limit in PWM Mode
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)
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. Devices are ESD sensitive. Handling precautions recommended.
4. Specification for packaged product only.
Condition
(turn-on)
V
EN
=>1.34V; V
FB
= 0.9V (not switching)
V
EN
= 0V
±
1%
±
2% (over temperature)
Min
2.6
2.4
Typ
2.5
280
1.3
5
0.7
400
1
6
0.2
0.2
0.060
0.035
1
1.24
1
1
Max
5.5
2.6
2.0
10
0.707
0.714
480
100
7.5
Units
V
V
mV
mA
µA
V
V
µA
nA
A
%
%
%
Ω
Ω
MHz
V
µA
µA
µA
µA
mV
0.693
0.686
320
V
FB
= 0.5V
V
OUT
1.2V; V
IN
= 2.6 to 5.5V, I
LOAD
= 100mA
100mA < I
LOAD
< 4000mA, V
IN
= 3.3V
V
FB
≤
0.5V
I
SW
= 1000mA; V
FB
=0.5V
I
SW
= 1000mA; V
FB
=0.9V
4.4
100
V
IN
= 2.6 to V
IN
= 5.5V
Ramp Control Current
V
PORH
= 5.5V; POR = High
Output Logic-Low Voltage (undervoltage condition),
I
POR
= 5mA
Threshold, % of V
OUT
below nominal
Hysteresis
0.8
1.14
0.7
0.7
1.2
1.34
1.3
1.3
1
2
135
7.5
10
2.7
150
10
12.5
%
%
°
C
°
C
February 2008
4
M9999-022108-A
Micrel, Inc.
MIC22400
Typical Characteristics
10
8
6
4
2
0
2.5
25°C
Shutdown Current
vs. Input Voltage
10
8
6
4
2
0
Shutdown Current
vs. Temperature
2.0
1.6
1.2
0.8
0.4
Operating Current
vs. Input Voltage
No Switching
V
IN
= 3.3V
TEMPERATURE (°C)
3.0 3.5 4.0 4.5 5.0
INPUT VOLTAGE (V)
5.5
0
2.5
FB = 0.9V
25°C
3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
2.0
1.6
1.2
Operating Current
vs. Temperature
0.710
Reference Voltage
vs. Input Voltage
0.710
Reference Voltage
vs. Temperature
0.705
0.705
0.700
0.8
0.4
0
No Switching
25°C
0.700
0.695
0.695
V
IN
= 3.3V
TEMPERATURE (°C)
FB = 0.9V
V
IN
= 3.3V
TEMPERATURE (°C)
0.690
2.5
3.0 3.5 4.0 4.5 5.0
INPUT VOLTAGE (V)
5.5
0.690
1.30
1.26
1.22
1.18
1.14
1.10
Enable Voltage
vs. Temperature
8
7
6
5
4
3
2
Enable Hysterisis
vs. Temperature
1060
1040
1020
1000
980
960
940
Frequency
vs. Temperature
V
IN
= 3.3V
TEMPERATURE (°C)
1
0
V
IN
= 3.3V
TEMPERATURE (°C)
920
900
TEMPERATURE (°C)
65
63
61
59
57
55
P-Channel RDS
ON
vs. Temperature
40
38
36
34
32
30
N-Channel RDS
ON
vs. Temperature
TEMPERATURE (°C)
TEMPERATURE (°C)
February 2008
5
M9999-022108-A
RF/Wirelessly
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