ADM6710 Analog Devices, ADM6710 Datasheet - Page 8

• Manufacturer Part Number: ADM6710
• Description: Low Voltage, High Accuracy, Triple/Quad Voltage Microprocessor Supervisory Circuit
• Manufacturer: Analog Devices

Specifications of ADM6710

• # Of Monitored Voltages: 4
• Manual Reset Capability: No
• Package: SOT
• Reset Threshold Summary: 11 Options-- 0.62 to 5V
• Reset Output-stage: Active-Low/Open-Drain
• Min Reset Timeout (ms): 140
• Typ Watchdog Timeout (ms): ---

ADM6710
THEORY OF OPERATION
The ADM6710 is a compact, low power supervisory circuit
capable of monitoring up to four voltages in a multisupply
application.
The device includes several factory-set voltage threshold
options for monitoring 1.8 V, 2.5 V, 3.0 V, 3.3 V and 5.0 V
supplies. It also provides up to three adjustable thresholds for
monitoring voltages down to 0.62 V. See the Ordering Guide
section for a list and description of all available options.
The ADM6710Q has three adjustable voltage inputs and is
powered by V
ADM6710 devices are powered by IN
voltage, and therefore monitors up to four voltages. If a monitored
voltage drops below its associated threshold, the active low reset
output asserts low and remains low while either IN
above 1.0 V.
INPUT CONFIGURATION
The ADM6710 provides numerous monitor choices with
adjustable reset thresholds. Typically, the threshold voltage at
each adjustable IN
than 0.62 V, connect a resistor divider network to the circuit as
depicted in Figure 13, where
The internal comparators each typically have a hysteresis of 0.3%
with respect to the reset threshold. This built-in hysteresis
improves the device’s immunity to ambient noise without
noticeably reducing the threshold accuracy. The ADM6710
is unaffected by short input transients.
The ADM6710 is powered from the monitored IN
case of the ADM6710Q. Monitored inputs are resistant to short
power supply glitches. Figure 7 depicts the ADM6710 glitch
immunity data. To increase noise immunity in noisy applications,
place a 0.1 μF capacitor between the IN
MONITORED
SUPPLIES
=
. 0
CC
Figure 13. Setting the Adjustable Monitor
62
, which is not a monitored voltage. All other
Figure 12. Typical Applications Circuit
x
input is 0.62 V. To monitor a voltage greater
⎛
⎜
⎜
⎝
R1
R2
V
1
IN
IN
IN
IN
INTH
ADM6710
+
1
2
3
4
2
GND
2
RESET
⎞
⎟
⎟
⎠
V
REF
= 0.62V
2
, which is a monitored
MICROPROCESSOR
2
input and ground.
2
1
, or V
or IN
CC
2
remains
in the
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Adding capacitance to IN
immunity.
Do not allow unused monitor inputs to float or to be grounded.
Connect these inputs to a supply voltage greater than their specified
threshold voltages. In the case of unused IN
limit the bias current by connecting a 1 MΩ series resistor between
the unused input and IN
RESET OUTPUT CONFIGURATION
The RESET output asserts low if a monitored IN
below its voltage threshold. Once all voltages rise above the
selected threshold level, the reset signal remains low for the
reset timeout period (200 ms typical). The reset output is open
drain with a weak internal pull-up to the monitored IN
supply, typically 10 μA.
Many applications that interface with other logic devices do not
require an external pull-up resistor. However, if an external
pull-up resistor is required and it is connected to a voltage
ranging from 0 V to 5.5 V, it will overdrive the internal pull-up.
Reverse current flow from the external pull-up voltage to IN
prevented by the internal circuitry.
ADDITION OF MANUAL RESET
Use the circuit shown in Figure 15 to add manual reset to any of
the ADM6710 adjustable inputs. When the switch is closed, the
analog input shorts to ground and a RESET output commences.
The switch must remain open for a minimum of 140 ms for the
RESET output to deassert.
Figure 15. Addition of Manual Reset (IN
Figure 14. Interface with a Different Logic Supply Voltage
ADM6710
IN
R2
R1
2
V
=3.3V
RESET
IN4
2
(or V
1
, IN
100kΩ
IN
IN
IN
IN
CC
ADM6710
3
, and IN
1
2
3
4
in the case of the ADM6710Q).
GND
RESET
RESET
4
4
is an Adjustable Input)
also improves noise
V
5V
CC
x
adjustable inputs,
x
voltage drops
2
or V
2
CC
is