ltc4242cuhf-trpbf Linear Technology Corporation, ltc4242cuhf-trpbf Datasheet - Page 20

• Manufacturer Part Number: ltc4242cuhf-trpbf
• Description: Dual Slot Hot Swap Controller For Pci Express
• Manufacturer: Linear Technology Corporation

LTC4242
Using P
θ
Impedance Graph, the worst-case junction-to-ambient
temperature rise occurs for the 12V MOSFET.
Table 4. MOSFET Power-Up Temperature Rise Calculation
There is a 20µs fi lter time when large current of 2x circuit
breaker’s threshold can fl ow in the switches. This time is
APPLICATIO S I FOR ATIO
20
JA(MAX)
VOLTAGE SUPPLY
3.3V
12V
ON
from the manufacturer’s Transient Thermal
and t
1
to look up the MOSFETs’ single pulse
U
0.5W
11W
P
ON
U
0.75°C/W
θ
0.6°C/W
JA(MAX)
W
8.3°C
0.3°C
U
ΔT
short enough to cause minimal increase in the junction-
to-ambient temperature of the MOSFETs, in the event of
powering up into short circuit or short circuiting after
power up. Therefore, in these events, it can be safely
assumed that the MOSFETs would have minimal thermal
stress on them.
If the LTC4242 operates in the diagnostic mode, user must
ensure a safe joule heating limit of the external MOSFET.
The internal switch will be disabled once the temperature
reaches 150°C, thereby preventing overheating.
4242f