Document
Features
n Complete Switch Mode Power Supply n Wide Input Voltage Range: 4.5V to 20V n 6A DC Typical, 8A Peak Output Current n 0.6V to 5V Output Voltage n Output Voltage Tracking and Margining n Remote Sensing for Precision Regulation (LTM4603
Only) n Typical Operating Frequency: 1MHz n PLL Frequency Synchronization n 1.5% Regulation n Current Foldback Protection (Disabled at Start-Up) n Pin Compatible with the LTM4601 n Pb-Free (e4) RoHS Compliant Package with Gold
Finish Pads n Ultrafast Transient Response n Current Mode Control n Up to 93% Efficiency at 5VIN, 3.3VOUT n Programmable Soft-Start n Output Overvoltage Protection n Small Footprint, Low Profile (15mm × 15mm ×
2.82mm) Surface Mount LGA Package
Applications
n Telecom and Networking Equipment n Servers n Industrial Equipment n Point of Load Regulation
LTM4603/LTM4603-1 20V, 6A DC/DC µModule Regulator with PLL, Output
Tracking and Margining Description
The LTM®4603 is a complete 6A step-down switch mode DC/DC µModule® regulator with onboard switching controller, MOSFETs, inductor and all support components. The device is housed in a small surface mount 15mm × 15mm × 2.82mm LGA package. Operating over an input voltage range of 4.5V to 20V, the LTM4603 supports an output voltage range of 0.6V to 5V as well as output voltage tracking and margining. The high efficiency design delivers 6A continuous current (8A peak). Only bulk input and output capacitors are needed to complete the design. The low profile (2.82mm) and light weight (1.7g) package easily mounts on the unused space on the back side of PC boards for high density point of load regulation. The µModule regulator can be synchronized with an external clock for reducing undesirable frequency harmonics and allows PolyPhase® operation for high load currents. A high switching frequency and adaptive on-time current mode architecture deliver a very fast transient response to line and load changes without sacrificing stability. An onboard remote sense amplifier can be used to accurately regulate an output voltage independent of load current. The onboard remote sense amplifier is not available in the LTM4603-1. The LTM4603/LTM4603-1 are pin compatible with the 12A LTM4601/LTM4601-1.
L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule and PolyPhase are registered trademarks and LTpowerCAD is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
1.5V/6A Power Supply with 4.5V to 20V Input
VIN 4.5V TO 20V
CIN
CLOCK SYNC TRACK/SS CONTROL
ON/OFF 392k
VIN PGOOD
PLLIN TRACK/SS VOUT
RUN
COMP
INTVCC DRVCC MPGM
LTM4603
SGND PGND
VFB MARG0
MARG1
VOUT_LCL DIFFVOUT
VOSNS+ VOSNS– fSET
100pF MARGIN CONTROL
40.2k
VOUT 1.5V 6A COUT
5% MARGIN
4603 TA01a
EFFICIENCY (%)
Efficiency vs Load Current with 12VIN
100 95 90 85 80 75 70 65 60 55 50 45 40 0
1
12VIN, 1.2VOUT 12VIN, 1.5VOUT 12VIN, 1.8VOUT 12VIN, 2.5VOUT 12VIN, 3.3VOUT 12VIN, 5VOU.