LTC4443/LTC4443-1

10

4443fa

APPLICATIONS INFORMATION

TYPICAL APPLICATION

LTC7510/LTC4443-1 12V to 1.5V/30A Digital Step-Down DC/DC Converter with PMBus Serial Interface

Bypassing and Grounding

(nanoseconds) and large AC currents (Amperes). Careless

component placement and PCB trace routing may cause

excessive ringing and undershoot/overshoot.

To obtain the optimum performance from the LTC4443:

A. Mount the bypass capacitors as close as possible

pins, and the BOOST and TS pins. The leads should

be shortened as much as possible to reduce lead

inductance.

B. Use a low inductance, low impedance ground plane

to reduce any ground drop and stray capacitance.

Remember that the LTC4443 switches greater than

5A peak currents and any significant ground drop will

degrade signal integrity.

C. Plan the power/ground routing carefully. Know where

the large load switching current is coming from and

going to. Maintain separate ground return paths for

the input pin and the output power stage.

D. Keep the copper trace between the driver output pin

and the load short and wide.

E. Be sure to solder the Exposed Pad on the back side of

the LTC4443 packages to the board. Correctly soldered

to a double-sided copper board, the LTC4443 has a

thermal resistance of approximately 43°C/W. Failure

to make good thermal contact between the exposed

back side and the copper board will result in thermal

resistances far greater.

TG

BOOST

C5

0.22μF

M1

RJK0305

2

M2

RJK0301

2

330μF

6

4443 TA02

L1

0.3μH

R3

C6

GND

TS

LTC4443-1

BG

IN

C4

C3

1μF

R2

+

C2

C1

1k

D1

R1

LOAD

RTN

SDATA

SCLK

SMB_AL_N

PWRGD

OUTEN

SYNC_IN

SYNC_OUT

FAULT1

FAULT2

PMBus

INTERFACE

7V DRIVE

12V

5V

GND

LTC7510

PWM

TEMPSEN

RESET_N

SADDR

FSET

1k

1k

1k

1k

POWER

MANAGEMENT

INTERFACE

MULTIPHASE

INTERFACE

FAULT

OUTPUTS

I-SHARE

+