A4410 Datasheet, PDF (24/41 Pages) Allegro MicroSystems – Programmable watchdog timer with a 30 ms activation delay

A4410
Adjustable Frequency Buck or Buck/Boost Pre-Regulator with a
Synchronous Buck, 3 Internal LDOs, Window Watchdog Timer, and NPOR
Table 3: Summary of Fault Mode Operation (continued)
FAULT TYPE and
CONDITION
A4410 RESPONSE TO FAULT
Slew pin open circuit
(SLEW_UC)
Results in an MPOR, so all regulators are shut off
NPOR
Low
Slew pin shorted to
ground (SLEW_OC)
Results in an MPOR, so all regulators are shut off
Low
The A4410 operates at a default oscillator frequency of 450
kHz. If the fault occurs before power up: 1V25 and 3 LDOs
Low
FSET/SYNC pin shorted ^{are OFF. VREG (unloaded) runs in pulse skipping mode.}
to ground or open circuit _{The A4410 operates at a default oscillator frequency of}
450 kHz. If the fault occurs after power up: 1V25 is OFF and
Low
3 LDOs are ON.
Charge pump (VCP)
over voltage
Results in an MPOR, so all regulators are shut off
Low
Charge pump (VCP)
under voltage
Results in an MPOR, so all regulators are shut off
Low
VCP pin open circuit
Results in VCP_UV and an MPOR, so all regulators are
shut off
Low
VCP pin shorted to
ground
Results on high current from the charge pump and
(intentional) fusing of an internal trace. Also results in
MPOR so all regulators are shut off.
Low
CP1 or CP2 pin open
circuit
Results in VCP_UV and an MPOR, so all regulators are
shut off
Low
CP1 pin shorted to
ground
Results in VCP_UV and an MPOR, so all regulators are
shut off
Low
CP2 pin shorted to
ground
Results on high current from the charge pump and
(intentional) fusing of an internal trace. Also results in
MPOR so all regulators are shut off.
Low
BG_VREF or BG_FAULT
under voltage
Results in an MPOR, so all regulators are shut off
Low
BG_VREF or BG_FAULT over
voltage
If BG_VREF is too high, all regulators will appear to be OV
(because BG_FAULT is good). If BG_FAULT is too high, all
regulators will appear to be UV (because BG_VREF is good)
Low
VCC under voltage or
shorted to ground
Results in an MPOR, so all regulators are shut off
Low
WD_ADJ pin shorted to A WD_ADJ fault only effects the NPOR output. The remainder
ground or open circuit
of the A4410 operates normally.
Low
Thermal shutdown
Results in an MPOR, so all regulators are shut off
Low
POK5V
Low
Low
LATCHED
FAULT?
YES
YES
RESET METHOD
Connect SLEW
pin then cycle EN
or VIN
Remove the short
then cycle EN or
VIN
Low
High
Remove the short
NO
circuit or connect
the pin
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
High
Low
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Check VCP/
CP1/CP2 pins &
components, then
cycle EN or VIN
Check VCP/CP1/
CP2 pins and
components
Connect the VCP
pin
Remove the
short circuit
and replace the
A4410
Connect the CP1
or CP2 pins
Remove the short
circuit
Remove the
short circuit
and replace the
A4410
Raise VIN or wait
for BGs to power
up
Replace the
A4410
Raise VIN or
remove short
from VCC pin
Remove the short
circuit or connect
the pin
Let the A4410
cool
Allegro MicroSystems, LLC
24
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com