ADM6339 Analog Devices, ADM6339 Datasheet - Page 9

• Manufacturer Part Number: ADM6339
• Description: Quad Voltage Microprocessor Supervisory Circuit
• Manufacturer: Analog Devices

Specifications of ADM6339

• # Of Monitored Voltages: 4
• Backup-battery Switch: n/a
• Manual Reset Capability: No
• Package: SOT
• Reset Threshold Summary: 13 Options-- -5 to 5V
• Reset Output-stage: Active-Low/Open-Drain
• Min Reset Timeout (ms): 140
• Watchdog Timer: No

When monitoring a voltage more negative than −0.5 V, a
scheme similar to that previously described in the Monitoring
Negative Voltages < −5.0 V section is used. For an input
monitor current error of <1%, the resistor network current
should be ≥500 μA (for I
based on the desired V
following equation:
where V
internal threshold voltage, −0.487 V (typical).
RESET OUTPUT CONFIGURATION
The RESET output asserts low if a monitored INx voltage
drops below its voltage threshold (or goes above its associated
threshold in the case of the −0.5 V and −5.0 V input options).
After all voltages exceed their associated threshold level, the
reset signal remains low for the reset timeout period, t
(200 ms typical).
RESET
=
INTH
IN
x
((
is the desired threshold voltage and V
V
TH
Figure 16. ADM6339 RESET Timing
/
t
RD
INTH
) − 1)
IN4
reset threshold voltage, using the
= 5 μA maximum). Calculate R
10%
t
RP
TH
is the
90%
RP
1
Rev. A | Page 9 of 12
RESET is open drain with a weak internal pull-up to IN
10 μA (typical). 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, the resistor
overdrives the internal pull-up. Reverse current flow from the
external pull-up voltage to IN
circuitry.
Figure 17. Interfacing with a Different Logic Supply Voltage
ADM6339
IN
2
= 3.3V
RESET
100kΩ
2
is prevented by the internal
RESET
V
5V
CC
ADM6339
2
of