Datasheet
LTM4637
1
4637fc
For more information www.linear.com/LTM4637
Typical applicaTion
DescripTion
20A DC/DC µModule
Step-Down Regulator
The LT M
®
4637 is a complete 20A output high efficiency
switch mode step-down DC/DC µModule (micromodule)
regulator. Included in the package are the switching control
-
ler, power FETs, inductor and compensation components.
Operating over an input voltage range from 4.5V to 20V,
the LTM4637 supports an output voltage range of 0.6V
to 5.5V, set by a single external resistor. Only a few input
and output capacitors are needed.
Current mode operation allows precision current sharing
of up to four LTM4637 regulators to obtain up to 80A
output. High switching frequency and a current mode
architecture enable a very fast transient response to line
and load changes without sacrificing stability. The device
supports frequency synchronization, multiphase/current
sharing, Burst Mode operation and output voltage tracking
for supply rail sequencing. A diode-connected PNP transis
-
tor is available for use as an internal temperature monitor.
The LTM4637 is offered in 15mm × 15mm × 4.32mm LGA
and 15mm × 15mm × 4.92mm packages. The LTM4637
is available with SnPb (BGA) or RoHS compliant terminal
finish. The LTM4637 is pin compatible with the LTM4627,
a 15A DC/DC µModule regulator.
L, LT , LT C , LT M , PolyPhase, Burst Mode, µModule, Linear Technology, the Linear logo are
registered trademarks and LTpowerCAD is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 5481178, 5847554, 6580258, 6304066, 6476589, 6774611, 6677210, 8163643.
12V
IN
, 1.2V
OUT
, 20A DC/DC µModule
®
Regulator
FeaTures
applicaTions
n
Complete 20A Switch Mode Power Supply
n
4.5V to 20V Input Voltage Range
n
0.6V to 5.5V Output Voltage Range
n
±1.5% Total DC Output Voltage Error
(–40°C to 125°C)
n
Differential Remote Sense Amplifier for Precision
Regulation for (V
OUT
≤ 3.3V)
n
Current Mode Control/Fast Transient Response
n
Parallel Current Sharing (Up to 80A)
n
Frequency Synchronization
n
Selectable Pulse-Skipping or Burst Mode
®
Operation
n
Soft-Start/Voltage Tracking
n
Up to 88% Efficiency (12V
IN
, 1.8V
OUT
)
n
Overcurrent Foldback Protection
n
Output Overvoltage Protection
n
Internal Temperature Monitor
n
Overtemperature Protection
n
15mm × 15mm × 4.32mm LGA and
15mm × 15mm × 4.92mm BGA Packages
n
SnPb (BGA) or RoHS Compliant (LGA and BGA) Finish
n
Telecom Servers and Networking Equipment
n
Industrial Equipment
n
Medical Systems
n
High Ambient Temperature Systems
12V
IN
Efficiency vs Load Current
COMP
TRACK/SS
RUN
f
SET
MODE_PLLIN
TEMP
PGOOD
V
OUT
V
OUT_LCL
DIFF_OUT
V
OSNS
+
V
OSNS
–
V
FB
LTM4637
V
IN
10k
R
FB
**
60.4k
22µF
16V
×4
0.1µF
100µF*
6.3V
×2
470µF
6.3V
×2
V
OUT
1.2V
20A
330pF
INTV
CC
2.2µF
EXTV
CC
* SEE TABLE 5
** SEE TABLE 1
4637 TA01a
V
IN
12V
SGND GND
+
OUTPUT CURRENT (A)
0
65
EFFICIENCY (%)
70
80
85
90
100
2
10
14
4637 TA01b
75
95
8
18
20
4
6
12 16
1.2V
OUT
250kHz
CCM