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AD5100
V
1MON
V
2MON
t
2SD_HOLD*
SHDN
AND RESET
SHDNWARN
NOTES
1. * = PROGRAMMABLE.
2. # = THE DURATION OF THE
Figure 7. V
V
2MON
is a high voltage monitoring input that controls the SHDN
V
2MON
and RESET functions of the external devices. V
inputs from 3 V to 30 V. It has a 16-level programmable turn-on
and turn-off (on, off) hysteresis thresholds (Register 0x03 and
Register 0x04), with an 8-step 0.07 ms to 200 ms shutdown hold
time (t
) and 0.07 ms to 1200 ms shutdown delay
2SD_HOLD
(t
).
2SD_DELAY
The V
pin is monitored by two comparators, one for turn-
2MON
on and one for turn-off detection, in the level-sensitive power-
up mode. Both are designed with 1.5% hysteresis. Only the
turn-on monitoring comparator is used if the rising edge
triggered wake-up mode is selected.
When the V
input goes above the programmed V
2MON
threshold, the comparator becomes active immediately, indicat-
ing that an on condition has occurred. Due to hysteresis, the
V
input must be brought below the programmed threshold
2MON
by 1.5% before the comparator becomes inactive, indicating that
the on condition has gone away (see Figure 8).
When the V
input drops below the programmed threshold,
2MON
the comparator becomes active immediately, indicating that a
V
off condition has occurred. Similarly, due to hysteresis,
2MON
the V
input must be brought above the programmed threshold
2MON
by 1.5% before the comparator becomes inactive, indicating that
the off condition has gone away.
t
t
1SD_DELAY*
1SD_DELAY*
t
t
1SD_HOLD*
1SD_HOLD*
t
t
FD_DELAY
FD_DELAY
t
MUST BE SHORTER THAN
MIN
Shutdown Timing Diagrams in Level-Sensitive Mode (Note that RESET Follows SHDN )
and V
1MON
2MON
monitors
2MON
on
2MON
t
GLITCH
t
GLITCH
t
#
MIN
t
2SD_HOLD*
t
2SD_DELAY*
t
FD_DELAY
t
OR ELSE THE AD5100 WILL BE POWERED OFF.
VREG_OFF_DELAY
V
2MON_ON
V
2MON
V
2MON_OFF
COMPARATOR
ACTIVE
By default, V
2MON
are both monitored. The on threshold chosen must be greater
than the off threshold.
When the SHDN output is activated by the input reaching
the V
threshold, such fault condition is temporarily
2MON_OFF
recorded in the fault detection register. The SHDNWARN
output transitions low for signaling before the shutdown output,
SHDN , activates. The timing of the SHDN output is dependent
on how long the shutdown programmed delay (t
relative to the SHDNWARN propagation delay (t
feature allows the system to finish any critical housekeeping
tasks before shutting down the external device. SHDN activates
once the voltage on V
than t
. RESET follows SHDN delay and hold timings when
GLITCH
triggered by V
2MON
The V
, shutdown, and shutdown warning timing diagrams
2MON
are shown in Figure 7.
Rev. A | Page 14 of 36
t
2SD_DELAY*
t
FD_DELAY
HYSTERESIS
ON
ON
COMPARATOR
INACTIVE
OFF
COMPARATOR
ACTIVE
Figure 8. V
Hysteresis
2MON
is level sensitive and the on and off thresholds
is outside the threshold for a time longer
2MON
.
V
1MON_OV*
V
1MON_UV*
V
2MON_ON*
V
2MON_OFF*
HYSTERESIS
OFF
COMPARATOR
INACTIVE
) is set
2SD_DELAY
). This
FD_DELAY
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