LTC4244IGN#TRPBF Linear Technology, LTC4244IGN#TRPBF Datasheet - Page 15

• Manufacturer Part Number: LTC4244IGN#TRPBF
• Description: IC CTRLR HOTSWAP PCI 20-SSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC4244IGN#TRPBF

• Applications: CompactPCI™
• Internal Switch(s): No
• Voltage - Supply: 3.3V, 5V, ±12V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.154", 3.91mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIO S I FOR ATIO
Table 1. t
The TIMER pin is immediately pulled low when the BD_SEL#
pin signal goes high.
Thermal Shutdown
The internal switches for the 12V and –12V supplies are
protected by a thermal shutdown circuit. When the junc-
tion temperature of the die reaches 150 C, all switches will
be latched off and the FAULT pin will be pulled low.
C
TIMER
0.22 F
0.33 F
0.47 F
0.68 F
0.82 F
0.1 F
TIMER
( 10%)
vs C
TIMER
U
t
TIMER(MIN)
U
115ms
164ms
238ms
287ms
35ms
77ms
LCL_PCI_RST#
HEALTHY#
BD_SEL#
10V/DIV
10V/DIV
10V/DIV
10V/DIV
10V/DIV
10V/DIV
3.3V
10V/DIV
TIMER
FAULT
GATE
OUT
W
Figure 4. Power-Up Into a Short on a 3.3V Output
10V/DIV
t
5V
TIMER(MAX)
162ms
243ms
346ms
500ms
603ms
74ms
OUT
U
10V/DIV
10V/DIV
12V
V
EEOUT
20ms/DIV
OUT
Short-Circuit Protection
During a normal power-up sequence, if the TIMER pin is
done ramping and any supply is still in current limit all of
the pass transistors will be immediately turned off and
FAULT will be pulled low as shown in Figure 4.
In order to prevent excessive power dissipation in the pass
transistors and prevent voltage spikes on the supplies
during short-circuit conditions, the current limit on each
supply is designed to be a function of the output voltage.
As the output voltage drops, the current limit decreases.
Unlike a traditional circuit breaker function where large
currents can flow before the breaker trips, the current
foldback feature guarantees that the supply current will be
kept at a safe level.
If either the 12V or –12V supply exceeds current limit
after power-up, the shorted supply’s current will drop
4244 F04
LTC4244/LTC4244-1
15
42441f