ADM6315 查看數據表（PDF） - Analog Devices
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ADM6315 Datasheet PDF : 8 Pages
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INTERFACING TO OTHER DEVICES
OUTPUT
The ADM6315 series is designed to integrate with as many
devices as possible. One feature of the ADM6315 is the RESET
open drain output, which can sink current from sources with a
voltage greater than the VCC of the ADM6315 input making it
suitable for use in more diverse applications.
THE BENEFITS OF A VERY ACCURATE RESET
THRESHOLD
Because the ADM6315 series can operate effectively even when
there are large degradations of the supply voltages (due to an
accurate internal voltage reference circuit), the possibility of a
malfunction during a power failure is greatly reduced.
VCC
VCC TRIP-POINT(MAX)
VCC TRIP-POINT
RST
VCC TO RESET
DELAY
VCC TRIP-POINT(MIN)
VOL
Figure 8. VCC Power-Down/Brownout Timing Diagram
DETAILED DESCRIPTION
The ADM6315 is designed to protect the integrity of a systems
operation by ensuring the proper operation of the system during
power-up, power-down and brownout conditions.
When the ADM6315 is powered-up (depending on the selected
reset active timeout), the RESET output of the ADM6315 will
remain low for a period typically equalling the 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 ex-
ecuting instructions. Initializing a system in this way provides a
more reliable start-up for microprocessor systems.
When a brownout condition occurs (assuming VCC is falling at
1 mV/µs), the ADM6315 will produce a reset in typically 35 µs.
Producing a reset this fast means that the entire system can be
reset together before any part of the systems’ voltage falls below
its recommended operating voltage. This can avoid dangerous
and/or erroneous operation of a microprocessor-based system.
MANUAL RESET INPUT
The ADM6315 also provides an additional input, MR. This
input can be used as either a means for the system operator to
manually reset the system via a switch or for a digital circuit to
reset the system.
ADM6315
The MR input will (typical) ignore negative going pulses faster
than 100 ns and is guaranteed to accept any negative going
input pulse of a duration greater than or equal to 1 µs. If MR is
connected to long cables or used in a noisy environment, then
placing a 1 µF decoupling capacitor between the MR input and
ground will further improve the glitch immunity of the ADM6315.
VCC TRIP-POINT (MIN)
VCC
VCC TRIP-POINT (MAX)
VCC TRIP-POINT
RESET ACTIVE TIMEOUT
RST
Figure 9. VCC Power-Up Timing Diagram
TRANSIENT IMMUNITY
As well as being an accurate reset circuit, the ADM6315 has
good immunity to negative going transients (Figure 5). Because
of this characteristic, the ADM6315 is suitable for use in noisy
environments.
Figure 5 shows the reset comparator overdrive (the maximum
magnitude of negative going pulses with respect to the typical
reset threshold) versus pulse duration, without causing a reset.
REV. 0
–5–
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