FAN2106_08 FAIRCHILD [Fairchild Semiconductor], FAN2106_08 Datasheet - Page 12

• Manufacturer Part Number: FAN2106_08
• Manufacturer: FAIRCHILD [Fairchild Semiconductor]

© 2006 Fairchild Semiconductor Corporation
FAN2106 Rev. 1.0.8
A shorted high-side MOSFET condition is detected
when SW voltage exceeds ~0.7V while the low-side
MOSFET is fully enhanced. The fault latch is set
immediately upon detection.
The two fault protection circuits above are active all the
time, including during soft-start.
Auto-Restart
After a fault, EN pin is discharged by a 1µA current sink
to a 1.1V threshold before the 800KΩ pull-up is
restored. A new soft-start cycle begins when EN
charges above 1.35V.
Depending on the external circuit, the FAN2106 can be
configured to remain latched-off or to automatically
restart after a fault.
Table 1. Fault / Restart Provisioning
With EN left open, restart is immediate.
If auto-restart is not desired, tie the EN pin to the VCC
pin or pull it high after V
keep the 1µA current sink from discharging EN to 1.1V.
Figure 24.
EN pin
Pull to GND
V
Open
Cap to GND
CC
Fault Latch with Delayed Auto-Restart
Controller / Restart State
OFF (disabled)
No restart – latched OFF(After V
comes up)
Immediate restart after fault
New soft-start cycle after:
t
DELAY
CC
(ms) = 3.9
comes up with a logic gate to
•
C(nf)
CC
12
Over-Temperature Protection
The chip incorporates an over-temperature protection
circuit that sets the fault latch when a die temperature of
about 150°C is reached. The IC restarts when the die
temperature falls below 125°C.
Power Good (PGOOD) Signal
PGOOD is an open-drain output that asserts LOW
when V
pin.
specifications section. PGOOD does not assert HIGH
until the fault latch is enabled (T1.0).
PCB Layout
Thresholds
Figure 25. Recommended PCB Layout
OUT
is out of regulation, as measured at the FB
are
specified
in
the
www.fairchildsemi.com
Electrical