2

GND

SN65HVDA1040A

CANL

6

CANH

7

SPLIT

5

3

V

= ½V

in normal mode,

floating in other modes

SPLIT

CC

V

CC

SN65HVDA1040A-Q1

SLLS995C

– FEBRUARY 2010 – REVISED FEBRUARY 2011

www.ti.com

Application Hints

Using With 3.3-V Microcontrollers

The input level threshold for the digital input pins of this device are 3.3V compatible, however a few application

considerations must be taken if using this device with 3.3-V microcontrollers. Both TXD and STB input pins have

their I/O pins in this case even though the pullup limits the current. As such care must be taken at the application

level that TXD and STB have sufficient pull up to meet system timing requirements for CAN. The internal pullup

on TXD especially may not be sufficient to overcome the parasitic capacitances and allow for adequate CAN

timing; thus, an additional external pullup may be required. Care should also be taken with the RXD pin of the

microcontroller as this device

not 5-V tolerant, this must be addressed at the application level. Other options include using a CAN transceiver

from Texas Instruments with I/O level adapting or a 3.3-V CAN transceiver.

Using SPLIT With Split Termination

The SPLIT pin voltage output provides 0.5

stabilized the common-mode voltage of the bus by connecting it to the center tap of split termination for the CAN

network (see Figure 17 and Figure 4). This pin provides a stabilizing recessive voltage drive to offset leakage

currents of un-powered transceivers or other bias imbalances that might bring the network common mode

voltage away from 0.5

behavior of the network by eliminating fluctuations in the bus common mode voltage levels at the start of

message transmissions.

Figure 4. Split Pin Stabilization Circuitry and Application

PCB and Thermal Considerations for VSON Package

The VSON package verson of this device has an exposed thermal pad which should be connected with vias to a

thermal plane. Even though this pad is not electrically connected internally it is recommended that the exposed

pad be connected to the GND plane. Please refer to the mechanical information on the package at the end of

this datasheet and application report SLUA271

"QFN/SON PCB Attachement" for more information on proper

use of this package.

6

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