Texas Instruments TPS386040EVM Evaluation Module TPS386040EVM TPS386040EVM Ficha De Dados
Códigos do produto
TPS386040EVM
(
)
CT
CT
DELAY
CT
CT
DELAY
CT
DELAY
CT
CT
DELA
V
= 1.24V, I
= 300 nA, T
= 1.4 ms
I
C
=
T
0.5 ms
V
Example for EVM CT pins with a desired T
= 1.4 ms
300 nA
C
=
(1.4 ms
0.5 ms) = 218 pF (choose C
= 220 pF)
1.24 V
T
´
-
´
-
Y
1.24 V
= 220 pF
+ 0.5 ms = 1.41 ms
300 nA
´
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Description
4.2.3
RESET Outputs
The TPS386000/40 RESET outputs are used on the EVM to enable the associated power supplies. The
TPS386000 has open drain outputs and are pulled up by R3-R6 pullup resistors by default on the
TPS386000EVM. The TPS386040 has push-pull outputs and R3-R6 are not installed on the
TPS386040EVM.
TPS386000 has open drain outputs and are pulled up by R3-R6 pullup resistors by default on the
TPS386000EVM. The TPS386040 has push-pull outputs and R3-R6 are not installed on the
TPS386040EVM.
Jumpers allow the RESET pins to be connected to an external power supply enable for use with a user
system.
system.
4.2.4
Timing Delay on CT Pins
Delay from SENSE input to output RESET can be adjusted with the value at the CT1-CT4 pins. Use the
following equations to adjust the delay from the nominal 1.3mS EVM value.
following equations to adjust the delay from the nominal 1.3mS EVM value.
4.3
Watch Dog Timer Function
The TPS386000/40 contains a watch dog timer (WDT) and the EVM contains a local WDT (LWDT) as well
as a provision for an external WDT connection. LWDT provides a pulse approximately every 140ms to the
TPS386000/40 WDI pin when configured by J11. LED D2 indicates when the LWDT is active.
as a provision for an external WDT connection. LWDT provides a pulse approximately every 140ms to the
TPS386000/40 WDI pin when configured by J11. LED D2 indicates when the LWDT is active.
The TPS386000/40 WDT function can be tested in the LWDT mode by holding LWDT in reset by placing
a shunt on J12 (RST LWDT). When a shunt is installed on J12, the WDO output on J9 will go to logic low
after approximately 600ms. WDO can be reset to logic high by pressing the S1 push-button switch to reset
the TPS386000/40.
a shunt on J12 (RST LWDT). When a shunt is installed on J12, the WDO output on J9 will go to logic low
after approximately 600ms. WDO can be reset to logic high by pressing the S1 push-button switch to reset
the TPS386000/40.
A system WDT can also be provided externally through J10 when J11 is set to the EXT WDT position.
9
SLVU341 – October 2009
Evaluation Module for TPS386000 and TPS386040
Copyright © 2009, Texas Instruments Incorporated