Datasheet

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AVAILABLE OPTIONS
DESCRIPTION (CONTINUED)
TPS3306-15
TPS3306-18 , TPS3306-20
TPS3306-25 , TPS3306-33
SLVS290C – APRIL 2000 – REVISED DECEMBER 2006
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be
more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
Table 1. SUPPLY VOLTAGE MONITORING
NOMINAL SUPERVISED VOLTAGE THRESHOLD VOLTAGE (TYP)
DEVICE
SENSE1 SENSE2 SENSE1 SENSE2
TPS3306-15 3.3 V 1.5 V 2.93 V 1.4 V
TPS3306-18 3.3 V 1.8 V 2.93 V 1.68 V
TPS3306-20 3.3 V 2 V 2.93 V 1.85 V
TPS3306-25 3.3 V 2.5 V 2.93 V 2.25 V
TPS3306-33 5 V 3.3 V 4.55 V 2.93 V
For the most current package and ordering information, see the Package Option Addendum at the end of this
document, or see the TI website at www.ti.com .
The various supervisory circuits are designed to monitor the nominal supply voltage, as shown in the Supply
Voltage Monitoring table.
During power-on, RESET is asserted when the supply voltage V
DD
becomes higher than 1.1 V. Thereafter, the
supervisory circuits monitor the SENSEn inputs and keep RESET active as long as SENSEn remains below the
threshold voltage V
IT
.
An internal timer delays the return of the RESET output to the inactive state (high) to ensure proper system
reset. The delay time, t
d(typ)
= 100 ms, starts after SENSE1 and SENSE2 inputs have risen above the threshold
voltage V
IT
. When the voltage at SENSE1 or SENSE2 input drops below the threshold voltage V
IT
, the output
becomes active (low) again.
The integrated power-fail (PFI) comparator with separate open-drain ( PFO) output can be used for low-battery
detection, power-fail warning, or for monitoring a power supply other than the main supply.
The TPS3306-xx devices integrate a watchdog timer that is periodically triggered by a positive or negative
transition of WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval,
t
t(out)
= 0.50 s, RESET becomes active for the time period t
d
. This event also reinitializes the watchdog timer.
Leaving WDI unconnected disables the watchdog.
The TPS3306-xx devices are available in either 8-pin MSOP or standard 8-pin SO packages, and are
characterized for operation over a temperature range of –40 ° C to +85 ° C.
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