SBVS157B
–
APRIL 2011
–
REVISED AUGUST 2011
APPLICATION INFORMATION
V
DD
TRANSIENT REJECTION
The TLV803 has built-in rejection of fast transients on the V
DD
pin. The rejection of transients depends on both
the duration and the amplitude of the transient. The amplitude of the transient is measured from the bottom of the
transient to the negative threshold voltage of the TLV803, as shown in
V
DD
V
IT-
Transient
Amplitude
t
w
Duration
Figure 7. Voltage Transient Measurement
The TLV803 does not respond to transients that are fast duration/low amplitude or long duration/small amplitude.
shows the relationship between the transient amplitude and duration needed to trigger a reset. Any
combination of duration and amplitude above the curve generates a reset signal.
RESET DURING POWER UP/DOWN
The TLV803 output is valid when V
DD
is greater than 1.1 V. When V
DD
is less than 1.1 V, the output transistor
turns off and becomes high impedance. The voltage on the RESET pin rises to the voltage level connected to the
pull-up resistor.
shows a typical waveform for power-up, assuming the RESET pin has a pull-up resistor
connected to the V
DD
pin.
V
IT
-
+ V
HYS
1.1 V
V
DD
t
d
RESET
Valid Output
Figure 8. Power-Up Response
6
Copyright
©
2011, Texas Instruments Incorporated
TI [ TEXAS INSTRUMENTS ]
