TYPICAL APPLICATIONS
POWER-UP AND VDD GOING LOW WITH SLEEP MODE AS DEFAULT LOW POWER MODE IS SELECTED
The first part of Figure 35 is identical to Figure 34. If VDD is pulled below the VDD under voltage reset (typ 4.6V), say by an
overcurrent or short circuit (for instance, short to 4.0 V), and if the low power mode previously selected was Sleep mode and if
the BATFAIL flag has been cleared, the 33742 enters in Reset mode for a time period of 100 ms. The WDOG pin stays HIGH,
but the high level (Voh) follows VDD level. The RST and INT pins are low. After 100 ms the 33742 goes into Sleep mode, and
the VDD and V2 are off.
Figure 35 shows an example wherein VDD is shorted to 4.0 V, and after 100 ms the 33742 enters Sleep mode.
.
Under voltage at VDD
VDD
Watchdog refresh
SPI (CS)
100 ms
WD
RST
INT
SBC in Sleep mode
SBC in Normal request
& reset modes
SBC in Normal
mode
SBC in
RESET
mode
SBC in Reset mode for
100ms, then enter
Sleep mode
Reset each 350 ms
Figure 35. Undervoltage at VDD. Sleep mode selected.
CANH
CANH (33742)
CANL (33742)
CANH (33742)
CANH
R6
R7
CH
CL
CH
R5
CANL
CANL (33742)
CANL
CAN Connector
CS
CL
CAN Connector
Legend
Legend
R5: 60 Ω
CL, CH: 220 pF
R6, R7: 30 Ω
CL, CH: 220 pF
CS: > 470 pF
Figure 37. CAN Bus Split Termination
Figure 36. CAN Bus Standard Termination
33742
Analog Integrated Circuit Device Data
Freescale Semiconductor
55
FREESCALE [ Freescale ]
