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
SymbolParameterConditionsMinMaxUnit
V
CC
I
CC
1/t
bit
V
CAN
V
diff
t
PD
T
amb
supply voltage4.55.5V
supply currentStandby mode-275A
maximum transmission speednon-return-to-zero1-MBd
CANH, CANL input/output voltage36+36V
differential bus voltage1.53.0V
propagation delayHigh-speed mode-50ns
ambient temperature40+125C
NXP Semiconductors
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
RXDV
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 numberPackage
NameDescriptionVersion
PCA82C251TSO8plastic small outline package; 8 leads; body width 3.9 mmSOT96-1
Product data sheetRev. 04 — 25 August 2011 2 of 17
7.1 Pinning
Fig 1.Block diagram
Fig 2.Pin configuration
NXP Semiconductors
7.2 Pin description
Table 3.Pin description
SymbolPinDescription
TXD1transmit data input
GND2ground
V
CC
RXD4receive data output
V
ref
CANL6LOW-level CAN voltage input/output
CANH7HIGH-level CAN voltage input/output
Rs8slope 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
3supply voltage
5reference 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
Product data sheetRev. 04 — 25 August 2011 3 of 17
NXP Semiconductors
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
SupplyTXDCANHCANLBus stateRXD
4.5 V to 5.5 V0HIGHLOWdominant0
4.5 V to 5.5 V1 (or floating) floatingfloatingrecessive1
4.5 V < VCC<5.5VX
0V<VCC< 4.5 VfloatingfloatingfloatingfloatingX
[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 RsModeResulting 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
<200ASlope control0.4VCC<VRs<0.6V
CC
floating if
>0.75V
V
Rs
CC
floating if
> 0.75V
V
Rs
StandbyIRs<10A
High-speedIRs< 500 A
PCA82C251
[1]
floatingX
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+36V
[2]
36+36V
[3]
40+150C
[4]
2500+2500V
[5]
250+250V
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 ParameterConditionsMinMaxUnit
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 voltage0.3+7.0V
DC voltage at pins 1, 4, 5 and 80.3VCC+0.3 V
DC voltage at pin 6 (CANL)0 V < VCC< 5.5 V; TXD HIGH or floating36+36V
DC voltage at pins 7 (CANH)0V < VCC< 5.5 V; no time limit36+36V
transient voltage at pins 6 and 7see Figure 8200+200V
storage temperature55+150C
ambient temperature40+125C
virtual junction temperature
electrostatic discharge voltage
fixed value to be used for the calculation of T
temperature (T
Product data sheetRev. 04 — 25 August 2011 5 of 17
NXP Semiconductors
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 +25C.
Product data sheetRev. 04 — 25 August 2011 10 of 17
NXP Semiconductors
14. Soldering of SMD packages
This text provides a very brief insight into a complex technology . A more in-depth account
of soldering ICs can be found in Application Note AN10365 “Surface mount reflow soldering description”.
14.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to
Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both
the mechanical and the electrical connection. There is no single soldering method that is
ideal for all IC packages. Wave soldering is often preferred when through-hole and
Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not
suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high
densities that come with increased miniaturization.
14.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from
a standing wave of liquid solder. The wave soldering process is suitable for the following:
PCA82C251
CAN transceiver for 24 V systems
• Through-hole components
• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reflow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature profile. Leaded packages,
packages with solder balls, and leadless packages are all reflow solderable.
Key characteristics in both wave and reflow soldering are:
• Board specifications, including the board finish, solder masks and vias
• Package footprints, including solder thieves and orientation
• The moisture sensitivity level of the packages
• Package placement
• Inspection and repair
• Lead-free soldering versus SnPb soldering
14.3 Wave soldering
Key characteristics in wave soldering are:
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
Product data sheetRev. 04 — 25 August 2011 11 of 17
NXP Semiconductors
14.4 Reflow soldering
Key characteristics in reflow soldering are:
• L ead-free versus SnPb sold ering; note that a lead-fr ee reflow process usually leads to
• Solder paste printing issues including smearing, release, and adjusting the process
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
Table 9.SnPb eutectic process (from J-STD-020C)
Package thickness (mm)Package reflow temperature (C)
< 2.5235220
2.5220220
PCA82C251
CAN transceiver for 24 V systems
higher minimum peak temperatures (see Figure 11
reducing the process window
window for a mix of large and small components on one board
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joint s (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 9
and 10
Volume (mm3)
< 350 350
) than a SnPb process, thus
Table 10.Lead-free process (from J-STD-020C)
Package thickness (mm)Package reflow temperature (C)
Volume (mm3)
< 350350 to 2000> 2000
< 1.6260260260
1.6 to 2.5260250245
> 2.5250245245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 11
Product data sheetRev. 04 — 25 August 2011 14 of 17
NXP Semiconductors
PCA82C251
CAN transceiver for 24 V systems
16. Legal information
16.1 Data sheet status
Document status
Objective [short] data sheetDevelopmentThis document contains data from the objective specification for product development.
Preliminary [short] data sheet QualificationThis document contains data from the preliminary specification.
Product [short] data sheetProductionThis document contains the product specification.
[1] Please consult the most recently issued document before initiating or completing a design.
[2] The term ‘short data sheet’ is explained in section “Definitions”.
[3] The product status of device(s) d escribed i n this docu ment may have changed si nce this d ocument was p ublished and may dif fer in case of multiple devices. The latest product statu s
information is available on the Internet at URL http://www.nxp.com.
[1][2]
Product status
[3]
Definition
16.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to co nt ain det ailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
16.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semi conductors’ aggregat e and cumulative liabil ity towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use in automotive applications — This NXP
Semiconductors product has been qualified for use in automotive
applications. The product is not designed, authorized or warranted to be
suitable for use in medical, military, aircraft, space or life support equipment,
nor in applications where failure or malfunction of an NXP Semiconductors
product can reasonably be expected to result in personal injury, death or
severe property or environmental damage. NXP Semiconductors accepts no
liability for inclusion and/or use of NXP Semiconductors products in such
equipment or applications and therefore such inclusion and/or use is at the
customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default ,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third part y
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell product s that is open for accept ance or the gr ant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
Product data sheetRev. 04 — 25 August 2011 15 of 17
NXP Semiconductors
PCA82C251
CAN transceiver for 24 V systems
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
Quick reference data — The Quick reference data is an extract of the
product data given in the Limiting values and Characteristics sections of this
document, and as such is not complete, exhaustive or legally binding.
16.4 Trademarks
Notice: All referenced brands, prod uct names, service names and trademarks
are the property of their respective owners.
17. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.