adm1069ast-reel Analog Devices, Inc., adm1069ast-reel Datasheet - Page 13

• Manufacturer Part Number: adm1069ast-reel
• Description: Super Sequencer With Margining Control
• Manufacturer: Analog Devices, Inc.

INPUTS
SUPPLY SUPERVISION
The ADM1069 has eight programmable inputs. Four of these
are dedicated supply fault detectors (SFDs). These dedicated
inputs are called VH and VPn (VP1 to VP3) by default. The
other four inputs are labeled VXn (VX1 to VX4) 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 device. Therefore, the ADM1069
can have up to eight analog inputs, a minimum of four analog
inputs and four 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 eight analog inputs has no
available digital inputs. Table 6 shows the details of each input.
VPn
PROGRAMMING THE SUPPLY FAULT DETECTORS
The ADM1069 has up to eight supply fault detectors (SFDs) on
its eight input channels. These highly programmable reset gen-
erators enable the supervision of up to eight 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 ADM1069. This translates to a voltage
resolution that is dependent on the range selected.
Table 6. Input Functions, Thresholds, and Ranges
Input
VH
VPn
VXn
ULTRA
LOW
LOW
MID
Function
High V Analog Input
Positive Analog Input
High Z Analog Input
Digital Input
SELECT
RANGE
Figure 21. Supply Fault Detector Block
VREF
+
–
+
–
COMPARATOR
COMPARATOR
OV
UV
Voltage Range (V)
2.5 to 6.0
6.0 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
FAULT TYPE
SELECT
GLITCH
FILTER
FAULT
OUTPUT
Maximum Hysteresis
425 mV
1.02 V
97.5 mV
212 mV
425 mV
97.5 mV
N/A
Rev. A | Page 13 of 36
The resolution is given by
Therefore, if the high range is selected on VH, the step size can
be calculated as follows:
Table 5 lists the upper and lower limit of each available range,
the bottom of each range (V
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
The threshold value required is given by
where:
V
V
N is the decimal value of the 8-bit code.
V
Reversing the equation, the code for a desired threshold is
given by
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
Therefore, N = 182 (1011 0110 or 0xB6).
T
R
B
is the desired threshold voltage (UV or OV).
is the voltage range.
is the bottom of the range.
Step Size = Threshold Range/255
(14.4 V − 6.0 V)/255 = 32.9 mV
V
N = 255 × (V
N = 255 × (5 − 2.5)/3.5
T
= (V
R
× N)/255 + V
Voltage Resolution (mV)
13.7
32.9
3.14
6.8
13.7
3.14
N/A
AN-721 Application
T
− V
B
)/V
B
R
B
), and the range itself (V
V
0.573
1.25
2.5
6.0
B
(V)
Note) is given by
Glitch Filter (μs)
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
ADM1069
V
0.802
1.75
3.5
8.4
R
R
(V)
).