ADM6711LAKS Analog Devices, ADM6711LAKS Datasheet - Page 6

• Manufacturer Part Number: ADM6711LAKS
• Description: Microprocessor Supervisory Circuit in 4-Lead SC70
• Manufacturer: Analog Devices

ADM6711/ADM6713
DETAILED DESCRIPTION
The ADM6711/ADM6713 are designed to protect the integrity
of a system’s operation by ensuring the proper operation of the
system during power-up, power-down, and brownout conditions.
When the ADM6711/ADM6713 are powered up, the RESET
output will remain low for a period equal to the typical reset
active timeout period. This is designed to give the system time
to power up correctly and for the power supply to stabilize
before any devices are brought out of reset and allowed to begin
executing instructions. Initializing a system in this way provides
a more reliable startup for microprocessor systems.
MANUAL RESET INPUT
The ADM6711/ADM6713’s manual reset (MR) input allows
the system operator to reset a system by means of an external
manual switch. Alternatively, a logic signal from another digital
circuit can be used to trigger a reset via the MR input.
The MR input will ignore negative-going pulses faster than
100 ns (typically) and is guaranteed to accept any negative-
going input pulse of a duration greater than or equal to 1 µs.
The RESET output will remain low while MR is held low and
for 240 ms (typically) after MR returns high.
If MR is connected to long cables or is used in a noisy environ-
ment, then placing a 0.1 µF capacitor between the MR input
and ground will help to remove any fast, negative-going transients.
POWER SUPPLY GLITCH IMMUNITY
The ADM6711/ADM6713 contain internal filtering circuitry
that provides immunity to fast transient glitches on the power
supply line. TPC 6 illustrates glitch immunity performance by
showing the maximum transient duration without causing a
reset pulse for glitches with amplitudes in the range of 1 mV to
1000 mV.
Glitch immunity makes the ADM6711/ADM6713 suitable for
use in noisy environments. Mounting a 0.1 µF decoupling
capacitor as close as possible to the V
immunity further.
CC
pin improves glitch
–6–
ADM6713 RESET OUTPUT LOGIC LEVELS
The ADM6713’s open-drain RESET output is designed for use
with an external pull-up resistor. This resistor can be tied to V
or any other reasonable voltage level, offering the flexibility to use
the ADM6713 to drive a variety of different logic level circuitry.
ENSURING A VALID RESET OUTPUT DOWN
TO V
When V
longer sinks current. Therefore, a high impedance CMOS logic
input connected to RESET may drift to undetermined logic
levels. To eliminate this problem, a pull-down resistor should be
connected from RESET to ground. A 100 kΩ resistor is large
enough not to load RESET and small enough to pull RESET
to ground.
CC
Figure 2. Ensuring a Valid RESET Output Down
to V
CC
= 0 V
CC
falls below 0.8 V, the ADM6711’s RESET output no
= 0 V
ADM6711
GND
V
V
CC
CC
RESET
100k
REV. 0
CC