Data Sheet

LTM4640

analog.com

Rev. 0

14 of 38

different levels. The LTM4640 has MODE/CLKIN and CLKOUT pins for PolyPhase operation of multiple devices or

frequency synchronization.

Pulling the RUN pin to GND forces the controller into its shutdown state, turning off both power MOSFETs and most

of the internal control circuitry. At light load currents, discontinuous-conduction mode (DCM) operation can be

enabled to achieve higher efficiency compared to continuous-conduction mode (CCM) by pulling the MODE/CLKIN

pin to GND. The TRACK/SS pin is used for power supply tracking and soft start programming. See the Applications

Information section for details.

Simplified Block Diagram

Figure 17. LTM4640 Simplified Block Diagram

Decoupling Requirements

Table 6. Decoupling Requirements

SYMBOL PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

CIN

External input capacitor requirement

(VIN = 3.1V to 20V, VOUT = 1.5V)

IOUT = 20A

33

44

µF

COUT

External output capacitor requirement

(VIN = 3.1V to 20V, VOUT = 1.5V)

IOUT = 20A

330 1

470 1

µF

1

Additional capacitance may be required under extreme temperature and/or capacitor bias voltage conditions

because of the variation of the actual capacitance over bias voltage and temperature.

POWER CONTROL

2.2µF

0.1µF

0.1µF

CIN

22µF

25V

INTVCC

TRACK/SS

RUN

VIN

MODE/CLKIN

CLKOUT

PHMODE

COMPa

COMPb

1µF

VOUT

VOSNS

–

VOSNS

+

FB

VIN

10kΩ

PGOOD

VOUT

1.5V,

20A

RFB

15kΩ

10kΩ

±0.5%

VIN

3.1V TO 20V

INTVCC

GND

0.18µH

FREQ

274kΩ

INTERNAL

COMP

GND

INTERNAL

FILTER

COUT

3 × 100µF

6.3V

DIFF

AMP

TSENSE–

TSENSE+

LTM4640