5
2006 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC1112
PWRGD
DELAY=1.5V
DELAY
VTT
SHORT-CIRCUIT DURING NORMAL
OPERATION
Once VTT drops out of
regulation, VTTGATE turns on
harder to try and raise VTT.
When VTT drops below 1.08V,
the delay capacitor is
discharged and PWRGD goes
low. When VTT drops below
0.7V, the delay capacitor
begins charging.
If VTT is still below 0.7V when
DELAY reaches 1.5V,
VTTGATE is latched off.
VTTIN
VTT=0.7V
VTT=1.08V
VTTGATE
VTT=0.7V
PWRGD
VTT=1.08V
DELAY
SHORT-CIRCUIT AND RECOVERY
DURING NORMAL OPERATION
VTT
Once VTT drops out of
regulation, VTTGATE turns on
harder to try and raise VTT.
When VTT drops below 1.08V,
the delay capacitor is discharged
and PWRGD goes low. When
VTT drops below 0.7V, the delay
capacitor begins charging.
If VTT recovers above 0.7V
before DELAY reaches 1.5V,
DELAY is again discharged.
If VTT reaches 1.08V the delay
capacitor begins charging and
normal operation continues.
VTTIN
VTT=1.08V
VTTGATE
DELAY=1.5V
Timing Diagrams (Cont.)
