ADM693AN Analog Devices Inc, ADM693AN Datasheet - Page 10
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ADM693AN
Manufacturer Part Number
ADM693AN
Description
IC SUPER MPU 4.4 100MA WD 16DIP
Manufacturer
Analog Devices Inc
Type
Battery Backup Circuitr
Datasheet
1.ADM694ANZ.pdf
(16 pages)
Specifications of ADM693AN
Rohs Status
RoHS non-compliant
Number Of Voltages Monitored
1
Output
Open Drain, Push-Pull
Reset
Active High/Active Low
Reset Timeout
35 ms Minimum
Voltage - Threshold
4.4V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Through Hole
Package / Case
16-DIP (0.300", 7.62mm)
Number Of Elements
1
Monitored Voltage 1 (typ)
4.5 to 5.5V
Threshold Voltage 1 (max)
4.48V
Watchdog Timer
Yes
Chip Enable Signals
Yes
Reset Active Time
70ms
Package Type
PDIP
Operating Supply Voltage (min)
4.5V
Operating Supply Voltage (max)
5.5V
Reset Threshold Voltage (max)
4.48V
Reset Threshold Voltage (min)
4.25V
Family Name
ADM693
Power Dissipation
600mW
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Power Fail Detection
Yes
Mounting
Through Hole
Pin Count
16
Supply Current
1.95mA
Battery Backup Switching
Yes
Manual Reset
No
Lead Free Status / RoHS Status
Not Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ADM693ANZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
ADM690–ADM695
+APPLICATION INFORMATION
Increasing the Drive Current
If the continuous output current requirements at V
100 mA or if a lower V
an external PNP pass transistor may be connected in parallel
with the internal transistor. The BATT ON output (ADM691/
ADM693/ADM695) can directly drive the base of the external
transistor.
Using a Rechargeable Battery for Back Up
If a capacitor or a rechargeable battery is used for back up then
the charging resistor should be connected to V
eliminates the discharge path that would exist during power
down if the resistor is connected to V
Adding Hysteresis to the Power Fail Comparator
For increased noise immunity, hysteresis may be added to the
power fail comparator. Since the comparator circuit is nonin-
verting, hysteresis can be added simply by connecting a resistor be-
tween the PFO output and the PFI input as shown in Figure 19.
POWER
POWER
INPUT
INPUT
RECHARGEABLE
+5V
+5V
BATTERY
BATTERY
Figure 17. Increasing the Drive Current
0.1 F
Figure 18. Rechargeable Battery
0.1 F
CC
–V
V
V
OUT
BATT
BATT
V
V
CC
CC
PNP TRANSISTOR
voltage differential is desired,
I =
ADM691
ADM693
ADM695
ADM69x
BATT
V
R
OUT
ON
CC
– V
R
.
BATT
V
V
OUT
OUT
OUT
0.1 F
0.1 F
since this
OUT
exceed
–10–
When PFO is low, resistor R
junction at the PFI pin. When PFO is high, the series combina-
tion of R
tion. This results in differing trip levels for the comparator.
Monitoring the Status of the Battery
The power fail comparator can be used to monitor the status of
the backup battery instead of the power supply if desired. This
is shown in Figure 20. The PFI input samples the battery volt-
age and generates an active low PFO signal when the battery
voltage drops below a chosen threshold. It may be necessary to
apply a test load in order to determine the loaded battery volt-
age. This can be done under processor control using CE
Since CE
test load will not be applied to the battery while it is in use, even
if the microprocessor is not powered.
Figure 19. Adding Hysteresis to the Power Fail Comparator
+7V TO +15V
POWER
INPUT
3
OUT
and R
is forced high during the battery backup mode, the
PFO
R
R
4
5V
0V
V
V
ASSUMING R
HYSTERESIS V
1
2
H
L
source current into the PFI summing junc-
= 1.3V
= 1.3V
0V
7805
(
(
1+ ––– – –––––––––––––
1+ ––– + –––
4
R
R
R
R
< <
H
+5V
1
2
1
2
3
PFI
V
– V
R
L
sinks current from the summing
ADM69x
3
L
R
R
R
1.3V (R
THEN
= 5V
1
3
1
1.3V
V
(5V – 1.3V)
IN
)
(
3 +
–––
V
R
R
V
CC
1
2
R
H
R
4
)
3
)
)
PFO
R
P NMI
4
OUT.
TO
REV. A