Datasheet
SLVS184C − NOVEMBER 1998 − REVISED DECEMBER 2005
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description
The TPS3705, TPS3707 family of microprocessor supply-voltage supervisors provide circuit initialization and
timing supervision, primarily for DSP and processor-based systems.
During power-on, RESET
is asserted when the supply voltage V
DD
becomes higher than 1.1 V. Thereafter, the
supply voltage supervisor monitors V
DD
and keeps RESET active as long as V
DD
remains below the threshold
voltage V
IT+
. An internal timer delays the return of the output to the inactive state (high) to ensure proper system
reset. The delay time, t
d
typ
= 200 ms, starts after V
DD
has risen above the threshold voltage V
IT+
. When the supply
voltage drops below the threshold voltage V
IT–
, the output becomes active (low) again. No external components
are required. All the devices of this family have a fixed-sense threshold voltage V
IT–
set by an internal voltage
divider.
The TPS3705-xx and TPS3707-xx devices incorporate a manual reset input, MR
. A low level at MR causes
RESET
to become active.
The TPS370x-xx families integrate a power-fail comparator which can be used for low-battery detection,
power-fail warning, or for monitoring a power supply other than the main supply.
The TPS3705-xx devices 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,
t
t(out)
= 1.6 s, WDO becomes active. This event also reinitializes the watchdog timer. Leaving WDI unconnected
disables the watchdog.
The TPS3707-xx devices do not have the Watchdog function, but include a high-level output RESET.
The product spectrum is designed for supply voltages of 2.5 V, 3 V, 3.3 V, and 5 V. The circuits are available in
either 8-pin MSOP or standard SOIC packages. The TPS3705, TPS3707 devices are characterized for
operation over a temperature range of −40°C to 85°C.
AVAILABLE OPTIONS
PACKAGED DEVICES
T
A
THRESHOLD
VOLTAGE
SMALL OUTLINE
(D)
POWER−PAD
µ-SMALL OUTLINE
(DGN)
MARKING DGN
PACKAGE
CHIP FORM
(Y)
2.63 V TPS3705−30D TPS3705−30DGN TIAAT TPS3705-30Y
2.93 V TPS3705−33D TPS3705−33DGN TIAAU TPS3705−33Y
4.55 V TPS3705−50D TPS3705−50DGN TIAAV TPS3705−50Y
−40°C to 85°C
2.25 V TPS3707−25D TPS3707−25DGN TIAAW TPS3707−25Y
−40 C to 85 C
2.63 V TPS3707−30D TPS3707−30DGN TIAAX TPS3707−30Y
2.93 V TPS3707−33D TPS3707−33DGN TIAAY TPS3707−33Y
4.55 V TPS3707−50D TPS3707−50DGN TIAAZ TPS3707−50Y