Datasheet

t (s) =
d
C (F)
SSx
0.5 10 (A)´
-6
´ 1.2 (V)
TPS75005
www.ti.com SBVS144C –NOVEMBER 2011–REVISED APRIL 2012
MONITOR BLOCKS
Supply Voltage Supervisors (SVS1 and SVS2)
The TPS75005 integrates two supply voltage supervisors (SVSs) to monitor the V
DD
and V
DDIO
pins of the C2000
controllers.
Delay Setting (CT1 and CT2)
The TPS75005 has a programmable delay function for both SVS1 and SVS2 that work independently of each
other. By default, both CT1 and CT2 are open, and both SVS1 and SVS2 take approximately 33 µs of delay time
from the comparator trip event to its output. By connecting an external capacitor(s) at the CT1 and/or CT2 pins,
the SVS delay time increases proportionately, as shown in the following equation:
(2)
where:
t
d
= delay time
C
CTx
= external capacitor value at CT1 or CT2 pin
See Figure 24 for an actual measurement curve.
For a long delay setting, use a very low leakage current capacitor such as X5R- or X7R-type to minimize
calculation errors from the previous equation.
All supported C2000 controllers work well with the TPS75005 default settings (without external delay capacitors).
NOTE
As with the SS1 and SS2 terminals, CT1 and CT2 are very high-impedance nodes with
very low values of constant current source. These two terminals cannot be monitored by
regular oscilloscope probes. Connecting such regular probes to CT1 or CT2 changes the
behavior of the soft-start function and no valid waveform can be monitored.
To monitor these terminals, use high-impedance probes, such as active FET probes.
Spike Noise Sensitivity
Application Report SBVA033, TPS75005 Advanced Information: Voltage Monitor Noise Immunity, explains
TPS75005 noise immunity performance.
Power-Down Monitoring
The TPS75005 monitors both OUT1 and OUT2 to become 0.3 V in power-down sequence so that next power-up
sequence starts from below 0.3 V.
See the SEQUENCER BLOCK section for more details.
NOTE
In any application circuit, a diode or two diodes in series should not be placed from
OUT1 (anode, 1.8 V) to OUT2 (cathode, 3.3 V). Such diode(s) prevent the TPS75005
from pulling OUT2 below 0.3 V; the device stays in a power-down sequence and will
not power up again.
Copyright © 2011–2012, Texas Instruments Incorporated Submit Documentation Feedback 17
Product Folder Link(s): TPS75005