ADM803RAKS-REEL-7 AD [Analog Devices], ADM803RAKS-REEL-7 Datasheet - Page 7

• Manufacturer Part Number: ADM803RAKS-REEL-7
• Description: Microprocessor Supervisory Circuits in 3-Lead SC70 and SOT-23
• Manufacturer: AD [Analog Devices]

TPC 7. Maximum Transient Duration without Causing a
Reset Pulse vs. Reset Comparator Overdrive
INTERFACING TO OTHER DEVICES’ OUTPUT
The ADM803/ADM809/ADM810 series is designed to integrate
with as many devices as possible and, therefore, has a standard
output dependent on V
both 3 V and 5 V or any nominal voltage within the minimum
and maximum specifications for V
approach, interfacing this device to other devices is simplified.
Ensuring a Valid Reset Output Down to V
When V
no longer sinks current. A high impedance CMOS logic input
connected to RESET may, therefore, drift to undetermined
logic levels. To eliminate this problem, a 100 kΩ resistor should
be connected from RESET to ground.
REV. C
Figure 3. Ensuring a Valid Reset Output Down
to V
400
350
300
250
200
150
100
CC
50
CC
0
1
falls below 0.8 V, the ADM803/ADM809’s RESET
= 0 V
ADM8_R/S/T/Z
RESET COMPARATOR OVERDRIVE, V
ADM809
GND
V
V
ADM8_L/M/J
CC
CC
CC
10
. This enables the part to be used in
RESET
CC
. Because of this design
100
TH
CC
– V
= 0 V
CC
(mV)
1000
–7–
Benefits of a Very Accurate Reset Threshold
In other microprocessor supervisory circuits, tolerances in supply
voltages lead to an overall increase in reset tolerance levels due
to the deterioration of the microprocessor reset circuit’s power
supply. The possibility of a malfunction during a power failure is
greatly reduced because the ADM803/ADM809/ADM810 series
can operate effectively even when there are large degradations
of the supply voltages. Another advantage of the ADM803/
ADM809/ADM810 series is its very accurate internal voltage
reference circuit. These benefits combine to produce an excep-
tionally reliable voltage monitor circuit.
Interfacing to Microprocessors with Multiple Interrupts
In a number of cases, it is necessary to interface many interrupts
from different devices (e.g., thermal, altitude, and velocity sensors).
The ADM803/ADM809/ADM810 can easily be integrated into
existing interrupt-handling circuits (Figure 4) or be used as a
standalone device.
Figure 4. Interfacing to Microprocessors with
Multiple Interrupts
ADM809
GND
V
V
CC
CC
RESET
ADM803/ADM809/ADM810
PRIORITY ENCODER
74LS147
OTHER SENSING
DEVICES
4-LINE BCD TO
MICROPROCESSOR