NXP PCA 82C251 T Datasheet

PCA82C251

CAN transceiver for 24 V systems

Rev. 04 — 25 August 2011 Product data sheet

1. General description

The PCA82C251 is the interface between a CAN protocol controller and the physical b us.
The device provides differential transmit capability to the bus and differential receive
capability to the CAN controller.

2. Features and benefits

 Fully compatible with the “ISO 11898-24 V” standard
 Slope control to reduce Radio Frequency Interference (RFI)
 Thermally protected
 Short-circuit proof to battery and ground in 24 V powered systems
 Low-current Standby mode
 An unpowered node does not disturb the bus lines
 At least 110 nodes can be connected
 High speed (up to 1 MBd)
 High immunity against electromagnetic interference.

3. Applications

 High-speed applications (up to 1 MBd) in trucks and busses.

4. Quick reference data

Table 1. Quick reference data

Symbol Parameter Conditions Min Max Unit

V

CC

I

CC

1/t

bit

V

CAN

V

diff

t

PD

T

amb

supply voltage 4.5 5.5 V
supply current Standby mode - 275 A
maximum transmission speed non-return-to-zero 1 - MBd
CANH, CANL input/output voltage 36 +36 V
differential bus voltage 1.5 3.0 V
propagation delay High-speed mode - 50 ns
ambient temperature 40 +125 C

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mbg613

SLOPE/

STANDBY

1

8

RECEIVER

4

REFERENCE

VOLT AGE

5

DRIVER

PROTECTION

2

7

3

6

V

CC

CANH
CANL

GND

V

ref

RXD

Rs

TXD

PCA82C251

PCA82C251

TXD

Rs

GND

CANH

V

CC

CANL

RXD V

ref

mbg612

1
2
3
4

6
5

8
7

5. Ordering information

PCA82C251

CAN transceiver for 24 V systems

Table 2. Ordering information

Type number Package

Name Description Version

PCA82C251T SO8 plastic small outline package; 8 leads; body width 3.9 mm SOT96-1

6. Block diagram

7. Pinning information

PCA82C251 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.

Product data sheet Rev. 04 — 25 August 2011 2 of 17

7.1 Pinning

Fig 1. Block diagram

Fig 2. Pin configuration

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7.2 Pin description

Table 3. Pin description

Symbol Pin Description

TXD 1 transmit data input
GND 2 ground
V

CC

RXD 4 receive data output
V

ref

CANL 6 LOW-level CAN voltage input/output
CANH 7 HIGH-level CAN voltage input/output
Rs 8 slope resistor input

8. Functional description

The PCA82C251 is the interface between a CAN protocol controller and the physical b us.
It is primarily intended for applications up to 1 MBd in trucks and buses. The device
provides differential transmit capability to the bus and differential receive capability to the
CAN controller. It is fully compatible with the “ISO 11898-24 V” standard.

PCA82C251

CAN transceiver for 24 V systems

3 supply voltage

5 reference voltage output

A current-limiting circuit protects the transmitter output stage against short-circuits to
positive and negative battery voltage. Although power dissipation will increase as a result
of a short circuit fault condition, this feature will prevent destruction of the transmitter
output stage.

If the junction temperature exceeds approximately 160 C, the limiting current of both
transmitter outputs is decreased. Because the transmitter is responsible for most of the
power dissipated, this will result in reduced power dissipation and hence a lower chip
temperature. All other parts of the IC will remain operational. The thermal protection is
needed, in particular, when a bus line is short-circuited.

The CANH and CANL lines are also protected against electrical transients which may
occur in an automotive environment.

Pin 8 (Rs) allows three different modes of operation to be selected: High-speed, Slope
control and Standby.

For high-speed operation, the transmitter output transistors are simply switched on and off
as fast as possible. In this mode, no measures are taken to limit the rise and fall slopes. A
shielded cable is recommended to avoid RFI problems. High-speed mode is selected by
connecting pin 8 to ground.

Slope control mode allows the use of an unshielded twisted pair or a p arallel pair of wires
as bus lines. To reduce RFI, the rise and fall slopes should be limited. The rise and fall
slopes can be programmed with a resistor connected from pin 8 to ground. The slope is
proportional to the current output at pin 8.

If a HIGH level is applied to pin 8, the circuit enters a low-current Standby mode. In this
mode, the transmitter is switched off and the recei ver is switched to a low current. If
dominant bits are detected (differential bus voltage >0.9 V), RXD will be switched to a

PCA82C251 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.

Product data sheet Rev. 04 — 25 August 2011 3 of 17

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LOW level. The microcontroller should react to this condition by switching the transceiver
back to normal operation (via pin 8). Because the receiver is slo wer in Standby mode, the
first message will be lost at higher bit rates.

Table 4. Truth table of the CAN transceiver

Supply TXD CANH CANL Bus state RXD

4.5 V to 5.5 V 0 HIGH LOW dominant 0

4.5 V to 5.5 V 1 (or floating) floating floating recessive 1

4.5 V < VCC<5.5V X

0V<VCC< 4.5 V floating floating floating floating X

[1] If another bus node is transmitting a dominant bit, then RXD is logic 0.
[2] X = don’t care.

Table 5. Pin Rs su mmary

Condition forced at pin Rs Mode Resulting voltage or current at pin Rs

V

Rs

10 A<I
VRs<0.3V

>0.75V

Rs

CAN transceiver for 24 V systems

[2]

CC

<200A Slope control 0.4VCC<VRs<0.6V

CC

floating if

>0.75V

V

Rs

CC

floating if

> 0.75V

V

Rs

Standby IRs<10A

High-speed IRs< 500 A

PCA82C251

[1]

floating X

CC

CC

[1]

[2]

9. Limiting values

amb

0V<V
0V<V

. The rating for Tvj limits the allowable combinations of power dissipation (Pd) and ambient

).

vj

< 5.5 V; no time limit

CC

< 5.5 V; no time limit

CC

[1]

36 +36 V

[2]

36 +36 V

[3]

40 +150 C

[4]

2500 +2500 V

[5]

250 +250 V

vj=Tamb+Pd

 R

th(vj-a)

, where R

th(j-a)

Table 6. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134). All voltages are referenced to pin 2; positive input
current.

Symbol Parameter Conditions Min Max Unit

V

CC

V

n

V

6

V

7

V

trt

T

stg

T

amb

T

vj

V

ESD

[1] TXD is LOW. Short-circuit protection provided for slew rates up to 5 V/s for voltages above +30 V.
[2] Short-circuit applied when TXD is HIGH, followed by TXD switched to LOW.
[3] In accordance with “IEC 60747-1”. An alternative definition of virtual junction temperature is: T

[4] Classification A: human body model; C = 100 pF; R = 1500 ; V = 2000 V.
[5] Classification B: machine model; C = 200 pF; R = 25 ; V = 200 V.

supply voltage 0.3 +7.0 V
DC voltage at pins 1, 4, 5 and 8 0.3 VCC+0.3 V
DC voltage at pin 6 (CANL) 0 V < VCC< 5.5 V; TXD HIGH or floating 36 +36 V

DC voltage at pins 7 (CANH) 0V < VCC< 5.5 V; no time limit 36 +36 V
transient voltage at pins 6 and 7 see Figure 8 200 +200 V
storage temperature 55 +150 C
ambient temperature 40 +125 C
virtual junction temperature
electrostatic discharge voltage

fixed value to be used for the calculation of T
temperature (T

is a

PCA82C251 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.

Product data sheet Rev. 04 — 25 August 2011 4 of 17

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10. Thermal characteristics

Table 7. Thermal characteristics

Symbol Parameter Conditions Typ Unit

R

th(j-a)

thermal resistance from junction to ambient in free air 160 K/W

11. Characteristics

PCA82C251

CAN transceiver for 24 V systems

Table 8. Characteristics

VCC= 4.5 V to 5.5 V; T

=40C to +125C; RL=60; I8>10A; unless otherwise specified; all voltages referenced to

amb

ground (pin 2) ; positive input current; all parameters are guaranteed over the ambient temperature range by design, but onl y



100 % tested at +25

C.

Symbol Parameter Conditions Min Typ Max Unit

Supply

I

3

supply current dominant; V1=1V; VCC=5.1V - - 78 mA

dominant; V
dominant; V
recessive; V
Standby

=1V; VCC=5.25V - - 80 mA

1

=1V; VCC=5.5V - - 85 mA

1

=4V; R8=47k --10mA

1

[1]

- - 275 A

DC bus transmitter

V
V
I

IH

I

IL

V
I

LO

V

V
V

IH
IL

6,7

7

6

HIGH-level input voltage output recessive 0.7V
LOW-level input voltage output dominant 0.3 - 0.3V
HIGH-level input current V1=4V 200 - +30 A
LOW-level input current V1=1V  - 600 A
recessive bus voltage V1= 4 V; no load 2.0 - 3.0 V
off-state output leakage current 2V<(V6, V7)<7V 2-+2 mA

CANH output voltage V1=1V; VCC=4.75V to 5.5V 3.0 - 4.5 V

CANL output voltage V1= 1 V 0.5 - 2.0 V
difference between output

6, 7

voltage at pins 6 and 7

I

I

sc7

sc6

short-circuit CANH current V7= 5V - - 200 mA

short-circuit CANL current V6= 36 V - - 200 mA

DC bus receiver: V

V

diff(r)

differential input voltage
(recessive)

V

diff(d)

differential input voltage
(dominant)

5V<(V

V

1

, V7)<36V 10 - +10 mA

6

=1V; VCC= 4.5 V to 4.75 V 2.75 4.5

V1= 1 V 1.5 - 3.0 V

=1V; RL=45 1.5 - - V

V

1

= 4 V; no load 500 - +50 mV

V

1

= 36 V - 100 - mA

V

7

= 4 V; pins 6 and 7 externally driven; 2V<(V6,V7) < 7 V; unless otherwise specified

1

[2]

1.0 - +0.5 V

7V<(V

6,V7

)<12V

[2]

1.0 - +0.4 V

0.9 - 5.0 V

7V<(V

) < 12 V; not Standby

6,V7

1.0 - 5.0 V

-VCC+0.3 V

CC

CC

V

mode
Standby mode 0.97 - 5.0 V
Standby mode; VCC= 4.5 V to 5.10 V 0.91 - 5.0 V

PCA82C251 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.

Product data sheet Rev. 04 — 25 August 2011 5 of 17

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PCA82C251

CAN transceiver for 24 V systems

Table 8. Characteristics …continued

VCC= 4.5 V to 5.5 V; T
ground (pin 2) ; positive input current; all parameters are guaranteed over the ambient temperature range by design, but onl y
100 % tested at +25C.

Symbol Parameter Conditions Min Typ Max Unit

V

diff(hys)

V

OH

V

OL

R

i

R

diff

differential input hysteresis see Figure 5 - 150 - mV
HIGH-level output voltage pin 4; I4= 100 A0.8V
LOW-level output voltage pin 4; I4= 1 mA 0 - 0.2V

input resistance CANH, CANL 5 - 25 k
differential input resistance 20 - 100 k

Reference output

V

ref

Timing (C

t

bit

t

onTXD

t

offTXD

t

onRXD

t

offRXD

t

onRXD

reference output voltage V8=1V;I5 <50A0.45V

= 100 pF; see Figure 3, Figure 4, Figure 6 and Figure 7)

L

minimum bit time R
delay TXD to bus active R
delay TXD to bus inactive R
delay TXD to receiver active R
delay TXD to receiver inactive R

delay TXD to receiver active R
SR CANH, CANL slew rate R
t

WAKE

wake-up time from Standby

(via pin 8)
t

dRXDL

bus dominant to RXD LOW V8= 4 V; see Figure 7 --3 s

Standby/Slope control (pin 8)

V

stb

I

slope

V

slope

input voltage for Standby mode 0.75VCC-- V

Slope control mode current 10 - 200 A

Slope control mode voltage 0.4V

=40C to +125C; RL=60; I8>10A; unless otherwise specified; all voltages referenced to

amb

-VCCV

CC

CC

=10mA 0 - 1.5 V

I

4

- 0.55V

CC

=4V; I5 <5A0.4V

V

8

=0 --1 s

ext

=0 - - 50 ns

ext

=0 -4080ns

ext

=0 - 55 120 ns

ext

=0; T

ext

= 4.5 V to 5.1 V

V

CC

R

=0; VCC= 4.5 V to 5.1 V - 80 170 ns

ext

=0; T

R

ext

=0k - 90 190 ns

R

ext

=47k - 290 400 ns

R

ext

=47k - 440 550 ns

ext

=47k -7- V/s

ext

<+85C

amb

<+85C - 90 170 ns

amb

- 80 150 ns

-0.6VCCV

CC

CC

see Figure 6 --20s

-0.6VCCV

CC

V

V

[1] I1=I4=I5=0mA; 0V<V6<VCC; 0 V < V7<VCC; V8=VCC; T
[2] This is valid for the receiver in all modes: High-speed, Slope control and Standby.

PCA82C251 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.

Product data sheet Rev. 04 — 25 August 2011 6 of 17

amb

< 90 C.