LTC7004 datasheet(13/18 Pages) LINER

13 / 18 page

LTC7004

7004fa

For more information www.linear.com/LTC7004

Figure 7. Protecting Load from Voltage Drops on VIN

TGUP

TGDN

INP

7004 F07

LTC7004

M1A

M1B

VIN

LOAD

Reverse Input Protection

To protect the load from discharging back into VIN when

the external MOSFET is off and the VIN voltage drops

below the load voltage, two external N-channel MOSFETs

should be used and must be in a back-to-back arrange-

ment as shown in Figure 7. Dual N-channel packages

such as the following devices are good choices for space

saving designs:

• FDS3890, Fairchild/ON Semiconductor

• IRF7380PbF, Infineon/IR

• SQJB80EP, Vishay/Siliconix

PC Board Layout Considerations

1. Solder the exposed pad on the backside of the LTC7004

package directly to the ground plane of the board.

2. Limit the resistance of the TS trace, by making it short

and wide.

3. CB needs to be close to chip.

4. Always include an option in the PC board layout to place

aresistorinserieswiththegateofanyexternalMOSFET.

High frequency oscillations are design dependent, and

having the option to add a series dampening resistor

can save a design iteration of the PC board.

APPLICATIONS INFORMATION

LTC7004 Datasheet(PDF) 13 Page - Linear Technology