Electronic Components Datasheet Search
ADM1069ASTZ Datasheet(PDF) 15 Page - Analog Devices
AD [Analog Devices]
ADM1069ASTZ Datasheet(HTML) 15 Page - Analog Devices
/ 32 page
Rev. C | Page 15 of 32
The hysteresis value is given by
is the desired hysteresis voltage.
is the decimal value of the 5-bit hysteresis code.
Note that N
has a maximum value of 31. The maximum
hysteresis for the ranges is listed in Table 6.
INPUT GLITCH FILTERING
The final stage of the SFDs is a glitch filter. This block provides
time-domain filtering on the output of the SFD comparators,
which allows the user to remove any spurious transitions such
as supply bounce at turn-on. The glitch filter function is in addition
to the digitally programmable hysteresis of the SFD comparators.
The glitch filter timeout is programmable up to 100 μs.
For example, when the glitch filter timeout is 100 μs, any pulse
appearing on the input of the glitch filter block that is less than
100 μs in duration is prevented from appearing on the output of
the glitch filter block. Any input pulse that is longer than 100 μs
appears on the output of the glitch filter block. The output is
delayed with respect to the input by 100 μs. The filtering
process is shown in Figure 23.
INPUT PULSE SHORTER
THAN GLITCH FILTER TIMEOUT
INPUT PULSE LONGER
THAN GLITCH FILTER TIMEOUT
Figure 23. Input Glitch Filter Function
SUPPLY SUPERVISION WITH VXx INPUTS
The VXx inputs have two functions. They can be used as either
supply fault detectors or digital logic inputs. When selected as
analog (SFD) inputs, the VXx pins have functionality that is very
similar to the VH and VPx pins. The primary difference is that the
VXx pins have only one input range: 0.573 V to 1.375 V. Therefore,
these inputs can directly supervise only the very low supplies.
However, the input impedance of the VXx pins is high, allowing
an external resistor divide network to be connected to the pin.
Thus, potentially any supply can be divided down into the input
range of the VXx pin and supervised. This enables the ADM1069
to monitor other supplies, such as +24 V, +48 V, and −5 V.
An additional supply supervision function is available when the
VXx pins are selected as digital inputs. In this case, the analog
function is available as a second detector on each of the dedi-
cated analog inputs, VPx and VH. The analog function of VX1
is mapped to VP1, VX2 is mapped to VP2, and so on. VX4 is
mapped to VH. In this case, these SFDs can be viewed as secondary
or warning SFDs.
The secondary SFDs are fixed to the same input range as the
primary SFDs. They are used to indicate warning levels rather
than failure levels. This allows faults and warnings to be gener-
ated on a single supply using only one pin. For example, if VP1
is set to output a fault when a 3.3 V supply drops to 3.0 V, VX1 can
be set to output a warning at 3.1 V. Warning outputs are available
for readback from the status registers. They are also OR’ed together
and fed into the SE, allowing warnings to generate interrupts on
the PDOs. Therefore, in this example, if the supply drops to 3.1 V,
a warning is generated, and remedial action can be taken before
the supply drops out of tolerance.
VXx PINS AS DIGITAL INPUTS
As discussed in the Supply Supervision with VXX Inputs
section, the VXx input pins on the ADM1069 have dual
functionality. The second function is as a digital logic input to
the device. Therefore, the ADM1069 can be configured for up to
four digital inputs. These inputs are TTL-/CMOS-compatible.
Standard logic signals can be applied to the pins: RESET from
reset generators, PWRGD signals, fault flags, manual resets, and
so on. These signals are available as inputs to the SE and, therefore,
can be used to control the status of the PDOs. The inputs can be
configured to detect either a change in level or an edge.
When configured for level detection, the output of the digital
block is a buffered version of the input. When configured for
edge detection, a pulse of programmable width is output from
the digital block once the logic transition is detected. The width
is programmable from 0 μs to 100 μs.
The digital blocks feature the same glitch filter function that is
available on the SFDs. This enables the user to ignore spurious
transitions on the inputs. For example, the filter can be used to
debounce a manual reset switch.
When configured as digital inputs, each VXx pin has a weak
(10 μA) pull-down current source available for placing the input
into a known condition, even if left floating. The current source,
if selected, weakly pulls the input to GND.
VREF = 1.4V
Figure 24. VXx Digital Input Function
Does ALLDATASHEET help your business so far?
[ DONATE ]
All Rights Reserved©
| English :
| Chinese :
| German :
| Japanese :
| Korean :
| Spanish :
| French :
| Italian :
| Polish :
| Vietnamese :