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EVAL-ADM1067LFEB View Datasheet(PDF) - Analog Devices

Part Name
Description
MFG CO.
EVAL-ADM1067LFEB
ADI
Analog Devices ADI
'EVAL-ADM1067LFEB' PDF : 32 Pages View PDF
ADM1067
INPUTS
SUPPLY SUPERVISION
The ADM1067 has 10 programmable inputs. Five of these are
dedicated supply fault detectors (SFDs). These dedicated inputs
are called VH and VPn (VP1 to VP4) by default. The other five
inputs are labeled VXn (VX1 to VX5) and have dual
functionality. They can be used as either supply fault detectors,
with similar functionality as VH and VPn, or CMOS-/TTL-
compatible logic inputs to the devices. Therefore, the ADM1067
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 available digital
inputs. Table 6 shows the details of each of the inputs.
ULTRA
LOW
VPn
RANGE
SELECT
OV
+ COMPARATOR
VREF
–
GLITCH
FILTER
FAULT
OUTPUT
LOW
MID
+
–
UV
FAULT TYPE
COMPARATOR SELECT
Figure 19. Supply Fault Detector Block
PROGRAMMING THE SUPPLY FAULT DETECTORS
The ADM1067 has up to 10 supply fault detectors (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 (undervoltage or overvoltage). The thresholds can
be programmed to an 8-bit resolution in registers provided in
the ADM1067. This translates to a voltage resolution that is
dependent on the range selected.
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 − 6.0 V)/255 = 32.9 mV
Table 5 lists the upper and lower limit of each available range,
the bottom of each range (VB), and the range itself (VR).
Table 5. Voltage Range Limits
Voltage Range (V)
0.573 to 1.375
1.25 to 3.00
2.5 to 6.0
6.0 to 14.4
VB (V)
0.573
1.25
2.5
6.0
VR (V)
0.802
1.75
3.5
9.6
The threshold value required is given by
VT = (VR × N)/255 + VB
where:
VT is the desired threshold voltage (UV or OV).
VR is the voltage range.
N is the decimal value of the 8-bit code.
VB is the bottom of the range.
Reversing the equation, the code for a desired threshold is given
by
N = 255 × (VT − VB)/VR
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 AN-698 Application Note) is given by
N = 255 × (5 − 2.5)/3.5
Therefore, N = 182 (1011 0110 or 0xB6).
Table 6. Input Functions, Thresholds, and Ranges
Input Function
Voltage Range (V)
VH
High V Analog Input
2.5 to 6.0
6.0 to 14.4
VPn Positive Analog Input 0.573 to 1.375
1.25 to 3.00
2.5 to 6.0
VXn High-Z Analog Input
0.573 to 1.375
Digital Input
0 to 5
Maximum Hysteresis
425 mV
1.02 V
97.5 mV
212 mV
425 mV
97.5 mV
N/A
Voltage Resolution (mV)
13.7
32.9
3.14
6.8
13.7
3.14
N/A
Glitch Filter (μs)
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
Rev. B | Page 14 of 32
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