AD5100
Rev. A | Page 15 of 36
The ranges of on and off thresholds are shown in Table 6 and
the programming codes for the selected-thresholds are found in
Table 7. The default on threshold is 7.47 V and off threshold is
6.95 V. Similarly, the ranges of shutdown hold and delay times
are shown in Table 8, and the programming codes of the selected
timings are found in Table 9. The default shutdown hold time is
10 ms and the delay time is 100 ms.
V
2MON_OFF
is ignored if V
2MON_OFF
is greater than V
2MON_ON
but
V
2MON_OFF
cannot equal V
2MON_ON.
If V
2MON
is selected with rising edge triggered wake-up mode,
only the on threshold is monitored and the off threshold
is ignored. V
2MON
is put into rising edge triggered mode by
setting V
2MON
off threshold, Register 0x04[3:0] to 1001
The voltage at V
1MON
provides the power for the AD5100, but a
valid signal on V
2MON
must be present before the internal V
REG
starts operating. Details are explained in the Power Requirements
section.
V
2MON
exhibits typical input resistance of 675 kΩ that users
should take into account for loading effect.
V
3MON
V
3MON
is a low voltage monitoring input that controls the
RESET function of an external device.
The V
3MON
pin is monitored by a comparator to detect an
undervoltage condition. It is designed with 1.5% hysteresis.
When the V
3MON
input drops below the programmed UV
threshold, the comparator becomes active immediately, indi-
cating that a UV condition has occurred. Due to hysteresis,
the V
3MON
input must be brought above the programmed UV
threshold by 1.5% before the comparator becomes inactive,
indicating that the UV condition has gone away (see Figure 9).
05
69
2-
0
10
V
3MON
V
3MON_UV
UV
COMPARATOR
INACTIVE
UV
COMPARATOR
INACTIVE
HYSTERESIS
Figure 9. V
3MON
Hysteresis
The V
3MON
comparator is used (in conjunction with a hold
timer) to control the RESET pin.
V
3MON
monitors inputs from 2.0 V to 5.5 V. It has an 8-step
programmable reset threshold (Register 0x05) with an 8-step
0.1 ms to 200 ms reset hold time (t
RS_HOLD
). The reset hold time
means that the RESET output remains activate when V
3MON
goes
above its UV threshold, until t
RS_HOLD
has elapsed. This allows
the reset of an external device to be held until the programmed
time is reached.
The V
3MON
and RESET timing diagrams are shown in
.
The range of thresholds is shown in
and the programming
code for the selected threshold is found in
. The range of
reset hold times is shown in
and the programming code
of the selected timing is found in
.
V
3MON
exhibits typical input resistance of 130 kΩ that users
should take into account for loading effect.
The MR input has an internal resistor pull-up toV
3MON
. The
RESET output is push-pull, between V
3MON
and GND.
05
69
2-
0
09
V
3MON
V
3MON
t
GLITCH
RESET
NOTES
1. * = PROGRAMMABLE
t
RS_HOLD*
t
RS_DELAY
t
RS_HOLD*
t
RS_DELAY
Figure 10. V
3MON
, RESET Timing Diagrams