Product specification
Supersedes data of 1997 Mar 14
File under Integrated Circuits, IC18
2000 Jan 13
Philips SemiconductorsProductspecification
CAN transceiver for 24 V systemsPCA82C251
FEATURES
• Fully compatible with the
“ISO 11898-24 V”
standard
• Slope control to reduce RFI
• Thermally protected
• Short-circuit proof to battery and ground in 24 V
powered systems
GENERAL DESCRIPTION
The PCA82C251 is the interface between the CAN
protocol controller and the physical bus. It is primarily
intended for applications (up to 1 Mbaud) in trucks and
buses. The device provides differentialtransmit capability
to the bus and differential receive capability to the CAN
controller.
• 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 Mbaud)
• High immunity against electromagnetic interference.
QUICK REFERENCE DATA
SYMBOLPARAMETERCONDITIONSMIN.MAX.UNIT
V
I
1/t
V
V
T
CC
CC
bit
CAN
diff
amb
supply voltage4.55.5V
supply currentstandby mode−275µA
maximum transmission speednon-return-to-zero1−Mbaud
CANH, CANL input/output voltage−36+36V
differential bus voltage1.53.0V
ambient temperature−40+125°C
5reference voltage output
CANL6LOW-level CAN voltage
input/output
CANH7HIGH-level CAN voltage
input/output
Rs8slope resistor input
2000 Jan 133
handbook, halfpage
1TXD
2
GNDCANH
V
RXD
CC
PCA82C251
3
4
MBG612
8Rs
7
6
CANL
V
5
ref
Fig.2 Pin configuration.
Philips SemiconductorsProductspecification
CAN transceiver for 24 V systemsPCA82C251
FUNCTIONAL DESCRIPTION
The PCA82C251 is the interface between the CAN
protocol controller and the physical bus. It is primarily
intended for applications up to 1 Mbaud 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.
A current limiting circuit protects the transmitter output
stage against short-circuit to positive and negative battery
voltage. Although the power dissipation is increased
during this fault condition, this feature will prevent
destruction of the transmitter output stage.
If the junction temperature exceeds a value of
approximately 160 °C, the limiting current of both
transmitter outputs is decreased. Because the transmitter
is responsible for the major part of the power dissipation,
this will result in a reduced power dissipation and hence a
lowerchip temperature. All other partsof the IC will remain
operating. The thermal protection is particularly needed
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 or 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 slope. Use of a shielded cable is
recommended to avoid RFI problems. The high-speed
mode is selected by connecting pin 8 to ground.
The slope control mode allows the use of an unshielded
twisted pair or a parallel pair of wires as bus lines.
To reduce RFI, the rise and fall slope should be limited.
The rise and fall slope 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 receiver is switched to a low current.
If dominant bits are detected (differential bus voltage
>0.9 V), RXD will be switched to a LOW level.
The microcontroller should react to this condition by
switching the transceiver back to normal operation
(via pin 8). Because the receiver is slower in standby
mode, the first message will be lost at higher bit rates.
Table 1 Truth table of the CAN transceiver
V
CC
TXDCANHCANLBUS STATERXD
4.5 to 5.5 V0HIGHLOWdominant0
4.5 to 5.5 V1 (or floating)floatingfloatingrecessive1
4.5<VCC< 5.5 VX
(1)
floating if
VRs> 0.75V
CC
floating if
VRs> 0.75V
floating1
CC
0<VCC< 4.5 VfloatingfloatingfloatingfloatingX
Notes
1. X = don’t care.
2. If another bus node is transmitting a dominant bit, then RXD is logic 0.
Table 2 Pin Rs summary
CONDITION FORCED AT PIN RsMODERESULTING VOLTAGE OR CURRENT AT PIN Rs
> 0.75V
V
Rs
10 µA<−I
VRs< 0.3V
CC
< 200 µAslope control0.4VCC<VRs< 0.6V
Rs
CC
standby−IRs<10µA
CC
high-speed−IRs< 500 µA
(2)
(2)
(1)
2000 Jan 134
Philips SemiconductorsProductspecification
CAN transceiver for 24 V systemsPCA82C251
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 60134); all voltages are referenced to pin 2;
positive input current.
SYMBOLPARAMETERCONDITIONSMIN.MAX.UNIT
V
CC
V
n
V
6
V
7
V
tr
T
stg
T
amb
T
vj
V
esd
supply voltage−0.3+7.0V
DC voltage at pins 1, 4, 5 and 8−0.3VCC+ 0.3 V
DC voltage at pin 6 (CANL)0V<VCC< 5.5 V; TXD HIGH
−36+36V
or floating
0V<V
< 5.5 V; no time
CC
−36+36V
limit; note 1
0V<V
< 5.5 V; no time
CC
−36+36V
limit; note 2
DC voltage at pin 7 (CANH)0V<VCC< 5.5 V; no time limit −36+36V
transient voltage on pins 6 and 7 see Fig.8−200+200V
storage temperature−55+150°C
ambient temperature−40+125°C
virtual junction temperaturenote 3−40+150°C
electrostatic discharge voltagenote 4−2500+2500V
note 5−250+250V
Notes
1. TXD is LOW. Short-circuit protection provided for slew rates up to 5 V/µs for voltages above +30 V.
2. Short-circuit applied when TXD is HIGH, followed by TXD switched to LOW.
3. In accordance with
Tvj=T
amb+Pd×Rth(vj-a)
“IEC 60747-1”
, where R
the allowable combinations of power dissipation (Pd) and ambient temperature (T
. An alternative definition of virtual junction temperature is:
is a fixed value to be used for the calculation of Tvj. The rating for Tvj limits
th(vj-a)
).
amb
4. Classification A: human body model; C = 100 pF; R = 1500 Ω; V = ±2500 V.
5. Classification B: machine model; C = 200 pF; R = 0 Ω; V = ±250 V.
THERMAL CHARACTERISTICS
SYMBOLPARAMETERCONDITIONSVALUEUNIT
R
th(j-a)
thermal resistance from junction to ambientin free air
PCA82C251100K/W
PCA82C251T160K/W
QUALITY SPECIFICATION
According to
“SNW-FQ-611 part E”
.
2000 Jan 135
Philips SemiconductorsProductspecification
CAN transceiver for 24 V systemsPCA82C251
CHARACTERISTICS
VCC= 4.5 to 5.5 V; T
to ground (pin 2); positive input current; all parameters are guaranteed over the ambient temperature range by design,
but only 100% tested at +25 °C.