9

LTC4440

4440i

Bypassing and Grounding

seconds) and large AC currents (Amperes). Careless

component placement and PCB trace routing may cause

excessive ringing and under/overshoot.

To obtain the optimum performance from the LTC4440:

A. Mount the bypass capacitors as close as possible

pins. The leads should be shortened as much as pos-

sible to reduce lead inductance.

B. Use a low inductance, low impedance ground plane to

reduce any ground drop and stray capacitance. Re-

member that the LTC4440 switches >2A peak currents

and any significant ground drop will degrade signal

integrity.

APPLICATIO S I FOR ATIO

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. When using the MS8E package, be sure to solder the

exposed pad on the back side of the LTC4440 package

sided 1oz copper board, the LTC4440 has a thermal

resistance of approximately 40

°C/W. Failure to make

good thermal contact between the exposed back side

and the copper board will result in thermal resistances

far greater than 40

°C/W.