Datasheet

LTC4232
13
4232fa
applicaTions inForMaTion
There are two V
DD
pins on opposite sides of the package
that connect to the sense resistor and MOSFET. The PCB
layout should be balanced and symmetrical to each V
DD
pin to balance current in the MOSFET bond wires. Figure 6
shows a recommended layout for the LTC4232.
Although the MOSFET is self protected from overtem-
perature, it is recommended to solder the backside of the
package to a copper trace to provide a good heat sink. Note
that the backside is connected to the SENSE pin and can-
not be soldered to the ground plane. During normal loads
the power dissipated in the MOSFET is as high as 1.9W.
A 10mm × 10mm area of 1oz copper should be sufficient.
This area of copper can be divided in many layers.
It is also important to put C1, the bypass capacitor for
the INTV
CC
pin as close as possible between the INTV
CC
and GND.
4232 F06
HEAT SINK
VIA TO
SINK
GND
C
OUTV
DD
Figure 6. Recommended Layout
Figure 7. 12V, 5A Backplane Resident Application with Insertion Activated Turn-On
Additional Applications
The LTC4232 has a wide operating range from 2.9V to 15V.
The UV, OV and PG thresholds are set with few resistors.
All other functions are independent of supply voltage.
In addition to Hot Swap applications, the LTC4232 also
functions as a backplane resident switch for removable
load cards (see Figure 7.)
The last page shows a 3.3V application with a UV threshold
of 2.87V, an OV threshold of 3.77V and a PG threshold
of 3.05V.
R5
150k
R6
20k
ADC
C1
0.1µF
R
MON
20k
4232 F07
V
DD
PG
OUT
FB
UV
GND
I
MON
I
SET
GATE
LTC4232DHC
OV
INTV
CC
TIMER
F LT
V
OUT
12V
5A
12V
R7
10k
R1
226k
R2
20k
12V
R4
20k
R3
140k
LOAD