LTM4637 Datasheet, PDF (1/28 Pages) Linear Technology – 20A DC/DC μModule Step-Down Regulator

FEATURES
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 (12VIN, 1.8VOUT)}
n _{Overcurrent Foldback Protection}
n _{Output Overvoltage Protection}
n _{Internal Temperature Monitor}
n _{Overtemperature Protection}
n _{15mm × 15mm × 4.32mm LGA Package}
APPLICATIONS
n _{Telecom Servers and Networking Equipment}
n _{Industrial Equipment}
n _{Medical Systems}
n _{High Ambient Temperature Systems}
LTM4637
20A DC/DC µModule
Step-Down Regulator
DESCRIPTION
The LTM^®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 a 15mm × 15mm × 4.32mm
LGA package. The LTM4637 is RoHS compliant. The
LTM4637 is pin compatible with the LTM4627, a 15A
DC/DC µModule regulator.
L, LT, LTC, LTM, 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.
TYPICAL APPLICATION
12V_IN, 1.2V_OUT, 20A DC/DC µModule^® Regulator
2.2µF
V_IN
12V
22µF
16V 10k
×4
V_IN EXTV_CC INTV_CC PGOOD
0.1µF COMP
V_OUT
TRACK/SS
V_{OUT_LCL}
RUN
LTM4637
f_SET
MODE_PLLIN
DIFF_OUT
V_OSNS+
V_OSNS–
330pF
100µF*₊
6.3V
×2
V_OUT
1.2V
20A
470µF
6.3V
×2
TEMP
* SEE TABLE 5
** SEE TABLE 1
SGND GND
VFB
R_FB**
60.4k
4637 TA01a
For more information www.linear.com/LTM4637
12V_IN Efficiency vs Load Current
100 _1.2VOUT
95
250kHz
CCM
90
85
80
75
70
65
0 2 4 6 8 10 12 14 16 18 20
OUTPUT CURRENT (A)
4637 TA01b
4637f
1