APX823/APX824/APX825A
PROCESSOR SUPERVISORY CIRCUITS
Description
Pin Assignments
(Top View)
The APX823/APX824/APX825A family of supervisors
provides circuit initialization and timing supervision, primarily
for DSP and processor-based systems.
5
4
1
2
3
VCC
RESET
GND
During power-on,
is asserted when supply voltage
RESET
APX823
VCC becomes higher than 1.1V. Thereafter, the supply
voltage supervisor monitors VCC and keeps active as
RESET
WDI
MR
long as VCC remains below the threshold voltage VTH-. An
internal timer delays the return of the output to the inactive
state (high) to ensure proper system reset. The delay time, td
SOT25
starts after VCC has risen above the threshold voltage VTH-
When the supply voltage drops below the threshold voltage
TH-, the output becomes active (low) again. No external
components are required. All the devices of this family have a
fixed-sense threshold voltage VTH- set by an internal voltage
divider.
.
(Top View)
V
5
4
1
2
3
VCC
RESET
GND
APX824
The APX823/APX825A devices incorporate a manual reset
WDI
RESET
input,
. A low level at
causes
MR
to become
RESET
MR
active. The APX824/APX825A devices include a high-level
output RESET. APX823/APX824/APX825A have a watchdog
timer that is periodically triggered by a positive or negative
transition at WDI. When the supervising system fails to
retrigger the watchdog circuit within the time-out interval,
SOT25
(Top View)
6
1
VCC
ttout,
becomes active for the time period td. This
RESET
GND
RESET
event also reinitializes the watchdog timer. Leaving WDI
unconnected disables the watchdog.
2
3
APX825A
SOT26
5
4
WDI
In applications where the input to the WDI pin may be active
(transitioning high and low) when the APX823/APX824/APX8
RESET
MR
25A asserting
the APX823/APX824/APX825A does
RESET
not return to a non-reset state when the input voltage is
above Vt. The product spectrum is designed for supply
voltage of 2.5V, 3V, 3.3V and 5V. The circuits are available in
a
SOT25
and
SOT26
packages.
The
APX823/APX824/APX825A devices are characterized for
operation over a temperature range of -40oC to 105oC.
Applications
Features
•
Applications Using DSPs, Microcontrollers, or
Microprocessors
•
Power-on reset generator with fixed delay time of 200ms
Typ
•
•
•
•
•
•
•
Industrial Equipment
Programmable Controls
Automotive Systems
Portable/Battery-Powered Equipment
Intelligent Instruments
•
•
Manual reset input (APX823/APX825A)
Reset output available in active-low
(APX823/APX824/APX825A), active-high
(APX824/APX825A)
Supply voltage supervision range 2.5V, 3V, 3.3V, 5V
Watchdog timer
•
•
•
•
•
Wireless Communications Systems
Notebook/Desktop Computers
Supply current of 30μA (Typ.)
Temperature range: -40°C to 85°C
SOT25 and SOT26: Available in “Green” Molding
Compound (No Br, Sb)
•
Lead Free Finish/RoHS Compliant (Note 1)
Note:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.
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www.diodes.com
May 2011
© Diodes Incorporated
APX823/APX824/APX825A
Document number: DS31323 Rev. 4 - 2