LTM4639

1

4639f

For more information www.linear.com/LTM4639

µModule Step-Down Regulator

TYPICAL APPLICATION

DESCRIPTION

The LTM®4639 is a complete 20A output high efficiency

switch mode step-down DC/DC µModule (micromodule)

regulator. Included in the package are the switching

controller, power FETs, inductor and compensation

components. Operating over an input voltage range from

2.375V to 7V, the LTM4639 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.

Currentmodeoperationallowsprecisioncurrentsharingof

up to four LTM4639 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 transistor

is included for use as an internal temperature monitor. For

up to 20V input operation, please see the LTM4637.

The LTM4639 is offered in a 15mm × 15mm × 4.92mm

BGA package. The LTM4639 is RoHS compliant.

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, 8163643.

FEATURES

APPLICATIONS

n

Complete 20A Switch Mode Power Supply

n

n

0.6V to 5.5V Output Voltage Range

n

±1.5% Maximum Total DC Output Voltage Error

(–40°C to 125°C)

n

Differential Remote Sense Amplifier for Precision

n

Current Mode Control/Fast Transient Response

n

Parallel Multiphase Current Sharing (Up to 80A)

n

Frequency Synchronization

n

n

Soft-Start/Voltage Tracking

n

n

Overcurrent Foldback Protection

n

Output Overvoltage Protection

n

Internal Temperature Monitor

n

Overtemperature Protection

n

15mm × 15mm × 4.92mm BGA Package

n

Telecom Servers and Networking Equipment

n

Industrial Equipment

n

Medical Systems

n

High Ambient Temperature Systems

n

3.3V Input Systems

3.3V to 1.5V Efficiency

and Power Loss

PGOOD

DIFF_OUT

LTM4639

5k

40.2k

100k

22µF

6.3V

×4

3.3V

0.1µF

4639 TA01a

COMPA

COMPB

TRACK/SS

RUN

MODE_PLLIN

SGND

GND OT_TEST

* SEE TABLE 5

** SEE TABLE 1

2.2µF

1µF

+5V BIAS

180pF

100µF*

6.3V

×2

680µF*

2.5V

×2

1.5V

20A

+

180pF

22pF

OUTPUT CURRENT (A)

0

70

80

85

90

100

4639 TA01b

75

95

0

1.0

1.5

2.0

2.5

3.0

3.5

4.5

0.5

4.0

18 20

14

12

16

6

10

8

2

4

EFFICIENCY

POWER LOSS

FREQ = 400kHz