Datasheet

Low Power Standby Mode, STB = high
RXD
Bus V
Diff
STB
t
BUS
<t
BUS
t
BUS
t
BUS
<t
BUS
<t
BUS
SN65HVDA1040A-Q1
SLLS995C –FEBRUARY 2010– REVISED FEBRUARY 2011 www.ti.com
Standby Mode and RXD Wake-Up Request
This is the low power mode of the device. It is selected by setting STB high. The CAN driver and main receiver
are turned off and bi-directional CAN communication is not possible. The low power receiver and bus monitor are
enabled to allow for wake up requests via the bus. A wake up request will be output to RXD (driven low) for any
dominant bus transmissions longer than the filter time t
BUS
. The local protocol controller (MCU) should monitor
RXD for transitions and then reactivate the device to normal mode based on the wake up request. The CAN bus
pins are weakly pulled to GND and the SPLIT pin is off (floating).
Figure 3. Standby Mode Low Power Receiver and Bus Monitor Behavior
Driver and Receiver Function Tables
Table 2. Driver Function Table
(1)
INPUTS OUTPUTS
BUS STATE
TXD STB CANH CANL
L L H L Dominant
H L Z Z Recessive
Open L Z Z Recessive
X H or Open Y Y Recessive
(1) H = high level, L = low level, X = irrelevant, Y = weak pull down to GND, ? = indeterminate, Z = high
impedance
Table 3. Receiver Function Table
DIFFERENTIAL INPUTS OUTPUT
STB BUS STATE
V
ID
= V(CANH) – V(CANL) RXD
V
ID
≥ 0.9 V L L Dominant
V
ID
≥ 1.15 V H or Open L Dominant
0.5 V < V
ID
< 0.9 V X ? ?
V
ID
≤ 0.5 V X H Recessive
Open X H Recessive
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