Inputs; Supply Supervision; Programming The Supply Fault Detectors - Analog Devices ADM1063 Manual

INPUTS

SUPPLY SUPERVISION

The ADM1063 has 10 programmable inputs. Five of these are
dedicated supply fault detectors (SFDs). These dedicated inputs
are called VH and VP1 to VP4 by default. The other five inputs
are labeled VX1 to VX5 and have dual functionality. They can
be used as either SFDs with similar functionality to VH and
VP1 to VP4, or CMOS-/TTL-compatible logic inputs to the
devices. Therefore, the ADM1063 can have up to 10 analog
inputs, a minimum of five analog inputs and five digital inputs,
or a combination. If an input is used as an analog input, it
cannot be used as a digital input. Therefore, a configuration
requiring 10 analog inputs has no digital inputs available.
Table 5 shows the details of each of the inputs.
RANGE
SELECT
ULTRA
LOW
COMPARATOR
+
VPn
–
VREF
+
LOW
–
MID COMPARATOR
Figure 22. Supply Fault Detector Block

PROGRAMMING THE SUPPLY FAULT DETECTORS

The ADM1063 can have up to 10 SFDs on its 10 input
channels. These highly programmable reset generators enable
the supervision of up to 10 supply voltages. The supplies can be
as low as 0.573 V and as high as 14.4 V. The inputs can be
configured to detect an undervoltage fault (the input voltage
drops below a preprogrammed value), an overvoltage fault (the
input voltage rises above a preprogrammed value), or an out-of-
window fault (an undervoltage or overvoltage). The thresholds
can be programmed to an 8-bit resolution in registers provided
in the ADM1063. This translates to a voltage resolution that is
dependent on the range selected.
Table 5. Input Functions, Thresholds, and Ranges
Input Function
VH High V analog input
VPn Positive analog input
VXn High Z analog input
Digital input
OV
GLITCH FAULT
FILTER OUTPUT
UV FAULT TYPE
SELECT
Voltage Range (V)
2.5 to 6.0
4.8 to 14.4
0.573 to 1.375
1.25 to 3.00
2.5 to 6.0
0.573 to 1.375
0 to 5
The resolution is given by
Step Size = Threshold Range/255
Therefore, if the high range is selected on VH, the step size can
be calculated as follows:
(14.4 V − 4.8 V)/255 = 37.6 mV
Table 4 lists the upper and lower limits of each available range,
the bottom of each range (V
Table 4. Voltage Range Limits
Voltage Range (V)
0.573 to 1.375
1.25 to 3.00
2.5 to 6.0
4.8 to 14.4
The threshold value required is given by
V = (V × N)/255 + V
T R
where:
V is the desired threshold voltage (UV or OV).
T
V is the voltage range.
R
N is the decimal value of the 8-bit code.
V is the bottom of the range.
B
Reversing the equation, the code for a desired threshold is given by
N = 255 × (V
For example, if the user wants to set a 5 V OV threshold on
VP1, the code to be programmed in the PS1OVTH register
(discussed in the
N = 255 × (5 − 2.5)/3.5
Therefore, N = 182 (1011 0110 or 0xB6).
Maximum Hysteresis Voltage Resolution (mV)
425 mV 13.7
1.16 V 37.6
97.5 mV 3.14
212 mV 6.8
425 mV 13.7
97.5 mV 3.14
N/A N/A
Rev. 0 | Page 13 of 36
), and the range itself (V
B
V (V)
B
0.573
1.25
2.5
4.8
B
− V )/V
T B R
AN-698 application note) is given by
Glitch Filter (µs)
ADM1063
).
R
V (V)
R
0.802
1.75
3.5
9.6
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100