Datasheet

V
DD
V
DD
WDR
WDT
RESET
WDI
GND
TPS3813
V
DD
RESET
I/O
GND
mC
C
WP
0.1 Fm 0.1 Fm
R
3
2
4
6
1
5
GND
WDT
V
DD
RESET
WDI
WDR
DBVPACKAGE
SOT-23
(TOPVIEW)
TypicalOperatingCircuit
TPS3813J25, TPS3813L30
TPS3813K33, TPS3813I50
www.ti.com SLVS331G –DECEMBER 2000–REVISED OCTOBER 2013
Processor Supervisory Circuits with Window-Watchdog
Check for Samples: TPS3813J25, TPS3813L30, TPS3813K33, TPS3813I50
During power on, RESET is asserted when supply
1
FEATURES
voltage (V
DD
) becomes higher than 1.1 V. Thereafter,
2
• Window-Watchdog With Programmable Delay
the supervisory circuit monitors V
DD
and keeps
and Window Ratio
RESET active as long as V
DD
remains below the
• 6-Pin SOT-23 Package
threshold voltage (V
IT
). An internal timer delays the
return of the output to the inactive state (high) to
• Supply Current of 9 μA (Typ)
ensure proper system reset. The delay time, t
d
= 25
• Power On Reset Generator With a Fixed Delay
ms typical, starts after V
DD
has risen above the
Time of 25 ms
threshold voltage (V
IT
). When the supply voltage
• Precision Supply Voltage Monitor 2.5 V, 3 V,
drops below the threshold voltage (V
IT
), the output
becomes active (low) again. No external components
3.3 V, 5 V
are required. All the devices of this family have a
• Open-Drain Reset Output
fixed-sense threshold voltage (V
IT
) set by an internal
• Temperature Range –40°C to +85° C
voltage divider.
For safety critical applications the TPS3813 family
APPLICATIONS
incorporates a so-called window-watchdog with
• Applications Using DSPs, Microcontrollers, or
programmable delay and window ratio. The upper
Microprocessors
limit of the watchdog time-out can be set by either
connecting WDT to GND, V
DD
, or using an external
• Safety Critical Systems
capacitor. The lower limit and thus the window ratio is
• Automotive Systems
set by connecting WDR to GND or V
DD
. The
• Heating Systems
supervised processor now needs to trigger the
TPS3813 within this window not to assert a RESET.
DESCRIPTION
The product spectrum is designed for supply voltages
The TPS3813 family of supervisory circuits provide
of 2.5 V, 3 V, 3.3 V, and 5 V. The circuits are
circuit initialization and timing supervision, primarily
available in a 6-pin SOT-23 package.
for DSPs and processor-based systems.
The TPS3813 devices are characterized for operation
over a temperature range of –40°C to 85°C.
1
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PRODUCTION DATA information is current as of publication date.
Copyright © 2000–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.