ADM1064 Analog Devices, ADM1064 Datasheet - Page 14

• Manufacturer Part Number: ADM1064
• Manufacturer: Analog Devices

Specifications of ADM1064

• # Supplies Monitored: 10
• Volt Monitoring Accuracy: 1%
• # Output Drivers: 10
• Fet Drive/enable Output: Both
• Voltage Readback: 12-bit ADC
• Package: 40 ld LFCSP ,48 ld TQFP

ADM1064
INPUTS
SUPPLY SUPERVISION
The ADM1064 has 10 programmable inputs. Five of these are
dedicated supply fault detectors (SFDs). These dedicated inputs
are called VH and VPx (VP1 to VP4) by default. The other five
inputs are labeled VXx (VX1 to VX5) and have dual functionality.
They can be used either as SFDs with functionality similar to
VH and VPx, or as CMOS-/TTL-compatible logic inputs to the
device. Therefore, the ADM1064 can have up to 10 analog inputs,
a minimum of five analog inputs and five digital inputs, or
a combination thereof. 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 input.
PROGRAMMING THE SUPPLY FAULT DETECTORS
The ADM1064 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 prepro-
grammed value), an overvoltage fault (the input voltage rises above
a preprogrammed value), or an out-of-window fault (the input
voltage is outside a preprogrammed range). The thresholds can be
programmed to an 8-bit resolution in registers provided in the
ADM1064. This translates to a voltage resolution that is dependent
on the range selected.
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 limits 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
Table 6. Input Functions, Thresholds, and Ranges
Input
VH
VPx
VXx
Step Size = Threshold Range/255
(14.4 V − 6.0 V)/255 = 32.9 mV
Function
High Voltage Analog Input
Positive Analog Input
High-Z Analog Input
Digital Input
B
), and the range itself (V
V
0.573
1.25
2.5
6.0
B
(V)
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 5.0
V
0.802
1.75
3.5
8.4
R
R
(V)
).
Rev. D | Page 14 of 32
Maximum Hysteresis
425 mV
1.02 V
97.5 mV
212 mV
425 mV
97.5 mV
N/A
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 overvoltage threshold
on VP1, the code to be programmed in the PS1OVTH register
(as discussed in the AN-698 Application Note at www.analog.com)
is given by
Therefore, N = 182 (1011 0110 or 0xB6).
INPUT COMPARATOR HYSTERESIS
The UV and OV comparators shown in Figure 19 are always
monitoring VPx. To avoid chatter (multiple transitions when the
input is very close to the set threshold level), these comparators
have digitally programmable hysteresis. The hysteresis can be
programmed up to the values shown in Table 6.
The hysteresis is added after a supply voltage goes out of tolerance.
Therefore, the user can program the amount above the under-
voltage threshold to which the input must rise before an
undervoltage fault is deasserted. Similarly, the user can program
the amount below the overvoltage threshold to which an input
must fall before an overvoltage fault is deasserted.
VPx
T
R
B
is the desired threshold voltage (undervoltage or overvoltage).
is the voltage range.
is the bottom of the range.
ULTRA
LOW
LOW
MID
V
N = 255 × (V
N = 255 × (5 − 2.5)/3.5
T
= (V
SELECT
RANGE
R
× N)/255 + V
Voltage Resolution (mV)
13.7
32.9
3.14
6.8
13.7
3.14
N/A
Figure 19. Supply Fault Detector Block
VREF
T
− V
B
)/V
+
–
+
–
R
B
COMPARATOR
COMPARATOR
OV
UV
FAULT TYPE
SELECT
Glitch Filter (μs)
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
0 to 100
GLITCH
FILTER
FAULT
OUTPUT