Siemens TLE 6252 G User Manual

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Fault Tolerant Differential CAN Transceiver TLE 6252 G

Target Data

Features

• Data transmission rate up to 125 kBaud

• Very low current consumption in stand-by and sleep mode

• Optimized EMI behavior due to limited and symmetric dynamic slopes of CANL and CANH signals

• Switches to single-wire mode during bus line failure events

• Supports one-wire transmission mode with ground offset voltages up to 1.5 V

• Preventation from bus occupation in case of CAN controller failure

• Fully-integrated receiver filters

• Short-circuit detection to battery and ground in 12 V powered systems

• Thermal protection

• Bus line error protection against transients in automotive environment

P-DSO-14-2

Type Ordering Code Package

▼ TLE 6252 G Q67006-A9337 P-DSO-14-2 (SMD)

▼ New type

Functional Description

The CAN Transceiver works as the interface between the CAN protocol c ontroller and the physical differential CAN bus. Figure 1 shows the principle configu ration of a CA N network.

The TLE 6252 is optimized for low-speed data transmission (up to 125 kBaud) in automotive and industrial applications.

In normal operation mode a differential sig nal is transmitted/rec eived. When bus wiring failures are detected t he device au tomaticall y switche s in single -wire mod e to maintain communication.

While no data is transferred, the power consumption c an be minimized by multiple low power modes.

Semiconductor Group 1 1998-11-01

TLE 6252 G

Local Area 1

Controller 1

RxD

TxD

Transceiver 1

Figure 1 CAN Network Example

Bus Line

Local Area 2

Controller 2

RxD

Transceiver 2

TxD

AES02410

Semiconductor Group 2 1998-11-01

Pin Configuration

(top view)

TLE 6252 G

P-DSO-14-2

Figure 2

INH

TxD

RxD

NERR

NSTB

ENT

WAKE

13 12

9 87

BAT

GND CANL CANH

RTL RTH

AEP02411

114 2 3 4 5 6

Semiconductor Group 3 1998-11-01

Table 1 Pin Definitions and Functions Pin No. Symbol Function

1INHInhibit output;

For controlling an external 5 V regulator

2TxDTransmit data input;

LOW: bus is dominant, HIGH: bus is recessive

3RxDReceive data output;

LOW: bus is dominant

4 NERR Error flag output;

LOW: bus error

5 NSTB Not stand-by input;

Digital control signal for low power modes

TLE 6252 G

6ENTEnable transfer input;

Digital control signal for low power modes

7 WAKE Wake-up input;

If level of

changes the device initials a wake-up from

WAKE

sleep mode by switching INH HIGH

8RTHTermination resistor output;

For CANH line, controlled by internal failure management

9RTLTermination resistor output;

For CANL line, controlled by internal failure and mode management

Supply voltage;

+5 V

11 CANH Bus line H;

HIGH: dominant state, external pull-down for termination

12 CANL Bus line L;

LOW: dominant state, external pull-up for termination 13 GND Ground 14

BAT

Battery voltage;

+ 12 V

Semiconductor Group 4 1998-11-01

Functional Block Diagram

TLE 6252 G

RTL

CANH

CANL

RTH

Filter

L Termination

Driver

Temperature

Protection

H Termination

Failure

Management

Output

Stage

BAT

TxD

RxD

Receiver

ENT

NSTB

Figure 3 Block Diagram

Failure Detect

Wake - Up Time - Out

Stand - By

Sleep

Wake - Up

Contol Unit

GND

NERR

INH

WAKE

AEB02412

Semiconductor Group 5 1998-11-01

TLE 6252 G

General Operation Modes

In addition to the normal operation mo de, the CAN transcei ver offers three mult iple l ow power operation modes to save power when there is no bus achieved: sleep mode, stand-by mode and VCC stand-by mode (see Table 2 and Figure 4). Via the control inputs NSTB and ENT the operation modes are selected by the CAN controller.

In sleep operation mode the l owest power consumption is achieved. To deac tivate the external voltage reg ulat or f or 5 V supply, th e INH output is swi tch ed to high impedance in this mode. Also CANL is pull ed-up to the batt ery voltage via the RTL output and the pull-up paths at input pins TxD and RxD are disabled from the internal supply.

On a wake-up request either by bus line activities or by the input WAKE, the transceiver automatically switches on the voltage regulat or (5 V supply). The WAKE input reacts to

rising and falling edges. As soon as

is provided, the wake-u p request can be read

on both the NERR and RxD outputs, upon which the microcontroller c an activate the normal operation mode by setting the control inputs NSTB and ENT high.

Bat

In NERR output in this mode is set l ow wh en the su pply vo ltage at pi n

-stand-by mode the wake up request is only reported at the RxD-output. The

was below the

bat

battery voltage threshold of 1 V.

When entering the normal mode the

-Flag is reseted and the N ERR becomes h igh

bat

again.

In addition the

-Flag is set at a first connection of the device to battery voltage. This

bat

feature is usefull e.g. when c hanging the ECU an d therefore a pre setting routine of the microcontroller has to be started.

If either of the supply voltage drop below the specified limits, the transceiver automatically goes to a stand-by mode.

Semiconductor Group 6 1998-11-01

TLE 6252 G

Table 2 Truth Table of the CAN Transceiver NSTB ENT Mode INH NERR RxD RTL

stand-by

BAT

0 0 sleep mode

bat

floating switched

active LOW wa ke- up i nte rrupt if

is present

switched to V

BAT

0 1 go to sleep

command

10VCC stand-by

1 1 normal mode V

floating switched

active LOW

bat

power-on

BAT

flag

bat

active LOW error flag

active LOW wake-up interrupt

HIGH = receive;

BAT

switched to V

switched

LOW = dominant receive data

Wake-up interrupts are releas ed w hen entering normal operation mo de.

If go to sleep command was used before. ENT may turn LOW as VCC drops, without affecting internal functions.

power-on flag will be reseted whe n ent ering normal operation mode.

BAT

Semiconductor Group 7 1998-11-01

Normal Operation

TLE 6252 G

NSTB = 0

ENT =10

NSTB ENT INH

NSTB10

=ENT

NSTB = 1

NSTB INH

NSTB

ENT11

HIGH

NSTB = ENT

1 =0 =

Go to Sleep

ENT

ENT INH

NSTB

=0ENT

float.

HIGH

(NSTB = 0

ENT = 0)

=00 or =

ENT

NSTB

=ENT 1

NSTB

==1

BAT

==1

NSTB ENT

Stand-ByStand-By

ENT

==1

NSTB ENT

==1

INH

HIGH

(Wake-Up from bus or via WAKE pin)

BAT

Sleep Mode

t>t

1=ENT

NSTB

ENT

INH

float.

AED02413

Figure 4 State Diagram

The transceiver will stay in a present operating mode until a suitable condition disposes a state change. If not otherwise defin ed all conditions are AND-com bined. The signals

and V

show if the supply is available (e.g. VCC = 1 : VCC voltage is present). If at

BAT

minimum one supply voltage is switched on, the start-up procedure begins (not figured). After a delay time the device changes to normal operating or stand-by mode.

Semiconductor Group 8 1998-11-01

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