LTC4100 datasheet(21/24 Pages) LINER

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LTC4100

sn4100 4100is

CONNECTOR

TO BATTERY

TO SYSTEM

4100 F13

VDD

Figure 10. Recommended SMBus Transient Protection

APPLICATIO S I FOR ATIO

Protecting SMBus Inputs

The SMBus inputs, SCL and SDA, are exposed to uncon-

trolled transient signals whenever a battery is connected

to the system. If the battery contains a static charge, the

SMBus inputs are subjected to transients which can cause

damage after repeated exposure. Also, if the battery’s

positive terminal makes contact to the connector before

the negative terminal, the SMBus inputs can be forced

below ground with the full battery potential, causing a

potential for latch-up in any of the devices connected to the

SMBus inputs. Therefore it is good design practice to

protect the SMBus inputs as shown in Figure 10.

4100 F15

VBAT

VIN

HIGH

FREQUENCY

CIRCULATING

PATH

BAT

SWITCH NODE

Figure 11. High Speed Switching Path

PCB Layout Considerations

For maximum efficiency, the switch node rise and fall

times should be minimized. To prevent magnetic and

electrical field radiation and high frequency resonant prob-

lems, proper layout of the components connected to the IC

is essential. (See Figure 11.) Here is a PCB layout priority

list for proper layout. Layout the PCB using this specific

order.

LTC4100 데이터시트(PDF) 21 Page - Linear Technology