Philips PCA82C251U, PCA82C251, PCA82C251T Datasheet

INTEGRATED CIRCUITS

DATA SHEET

PCA82C251

CAN transceiver for 24 V systems

Product specification

2000 Jan 13

Supersedes data of 1997 Mar 14

File under Integrated Circuits, IC18

Philips Semiconductors	Product specification
CAN transceiver for 24 V systems	PCA82C251

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

∙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

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 differential transmit capability to the bus and differential receive capability to the CAN controller.

SYMBOL		PARAMETER	CONDITIONS	MIN.	MAX.	UNIT
VCC	supply voltage			4.5	5.5	V
ICC	supply current		standby mode	−	275	μA
1/tbit	maximum transmission speed		non-return-to-zero	1	−	Mbaud
VCAN	CANH, CANL input/output voltage			−36	+36	V
Vdiff	differential bus voltage			1.5	3.0	V
Tamb	ambient temperature			−40	+125	°C
ORDERING INFORMATION
TYPE			PACKAGE
NUMBER	NAME		DESCRIPTION			CODE
PCA82C251	DIP8	plastic dual in-line package; 8 leads (300 mil)				SOT97-1
PCA82C251T	SO8	plastic small outline package; 8 leads body width 3.9 mm				SOT96-1
PCA82C251U	−	bare die; 2840 × 1780 × 380 μm				−

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Philips Semiconductors	Product specification
CAN transceiver for 24 V systems	PCA82C251
BLOCK DIAGRAM

				VCC
				3
TXD	1		PROTECTION
			DRIVER
Rs	8	SLOPE/
		STANDBY
	4				7
RXD					CANH
					CANL
			RECEIVER		6
Vref	5	REFERENCE
			PCA82C251
		VOLTAGE
				2	MBG613
				GND

		Fig.1	Block diagram.
PINNING
SYMBOL	PIN	DESCRIPTION
TXD	1	transmit data input			handbook, halfpage
GND	2	ground
					TXD	1		8	Rs
VCC	3	supply voltage			GND	2	PCA82C251	7	CANH
RXD	4	receive data output			VCC	3		6	CANL
Vref	5	reference voltage output
					RXD	4		5	Vref
CANL	6	LOW-level CAN voltage
		input/output					MBG612
CANH	7	HIGH-level CAN voltage
		input/output			Fig.2		Pin configuration.
Rs	8	slope resistor input

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Philips Semiconductors	Product specification
CAN transceiver for 24 V systems	PCA82C251

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 lower chip temperature. All other parts of 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

VCC				TXD	CANH	CANL	BUS STATE	RXD
4.5 to 5.5 V				0	HIGH	LOW	dominant	0
4.5 to 5.5 V				1 (or floating)	floating	floating	recessive	1(2)
4.5 < V	CC		< 5.5 V	X(1)	floating if	floating if	floating	1(2)
					VRs > 0.75VCC	VRs > 0.75VCC
0 < V		< 4.5 V		floating	floating	floating	floating	X(1)
CC

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 Rs	MODE	RESULTING VOLTAGE OR CURRENT AT PIN Rs
VRs > 0.75VCC	standby	−IRs < 10 μA
10 μA < −IRs < 200 μA	slope control	0.4VCC < VRs < 0.6VCC
VRs < 0.3VCC	high-speed	−IRs < 500 μA

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Philips Semiconductors	Product specification
CAN transceiver for 24 V systems	PCA82C251

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
VCC	supply voltage		−0.3	+7.0	V
Vn	DC voltage at pins 1, 4, 5 and 8		−0.3	VCC + 0.3	V
V6	DC voltage at pin 6 (CANL)	0 V < VCC < 5.5 V; TXD HIGH	−36	+36	V
		or floating
		0 V < VCC < 5.5 V; no time	−36	+36	V
		limit; note 1
		0 V < VCC < 5.5 V; no time	−36	+36	V
		limit; note 2
V7	DC voltage at pin 7 (CANH)	0 V < VCC < 5.5 V; no time limit	−36	+36	V
Vtr	transient voltage on pins 6 and 7	see Fig.8	−200	+200	V
Tstg	storage temperature		−55	+150	°C
Tamb	ambient temperature		−40	+125	°C
Tvj	virtual junction temperature	note 3	−40	+150	°C
Vesd	electrostatic discharge voltage	note 4	−2500	+2500	V
		note 5	−250	+250	V

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 “IEC 60747-1”. An alternative definition of virtual junction temperature is:

Tvj = Tamb + Pd × Rth(vj-a), where Rth(vj-a) is a fixed value to be used for the calculation of Tvj. The rating for Tvj limits the allowable combinations of power dissipation (Pd) and ambient temperature (Tamb).

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

SYMBOL	PARAMETER	CONDITIONS	VALUE	UNIT
Rth(j-a)	thermal resistance from junction to ambient	in free air
	PCA82C251		100	K/W
	PCA82C251T		160	K/W

QUALITY SPECIFICATION

According to “SNW-FQ-611 part E”.

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Philips Semiconductors	Product specification
CAN transceiver for 24 V systems	PCA82C251

CHARACTERISTICS

VCC = 4.5 to 5.5 V; Tamb = −40 to + 125 °C; RL = 60 Ω; I8 > −10 μA; unless otherwise specified; all voltages referenced 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.

SYMBOL	PARAMETER	CONDITIONS	MIN.	TYP.	MAX.	UNIT
Supply
I3	supply current	dominant; V1 = 1 V;	−	−	78	mA
		VCC < 5.1 V
		dominant; V1 = 1 V;	−	−	80	mA
		VCC < 5.25 V
		dominant; V1 = 1 V;	−	−	85	mA
		VCC < 5.5 V
		recessive; V1 = 4 V;	−	−	10	mA
		R8 = 47 kΩ
		standby; note 1	−	−	275	μA
DC bus transmitter
VIH	HIGH-level input voltage	output recessive	0.7VCC	−	VCC + 0.3	V
VIL	LOW-level input voltage	output dominant	−0.3	−	0.3VCC	V
IIH	HIGH-level input current	V1 = 4 V	−200	−	+30	μA
IIL	LOW-level input current	V1 = 1 V	−100	−	−600	μA
V6, 7	recessive bus voltage	V1 = 4 V; no load	2.0	−	3.0	V
ILO	off-state output leakage	−2 V< (V6, V7) < 7 V	−2	−	+2	mA
	current	−5 V< (V6, V7) < 36 V	−10	−	+10	mA
V7	CANH output voltage	V1 = 1 V; VCC = 4.75 to 5.5 V	3.0	−	4.5	V
		V1 = 1 V; VCC = 4.5 to 4.75 V	2.75	−	4.5	V
V6	CANL output voltage	V1 = 1 V	0.5	−	2.0	V
V6,7	difference between output	V1 = 1 V	1.5	−	3.0	V
	voltage at pins 6 and 7	V1 = 1 V; RL = 45 Ω	1.5	−	−	V
		V1 = 4 V; no load	−500	−	+50	mV
Isc7	short-circuit CANH current	V7 = −5 V	−	−	−200	mA
		V7 = −36 V	−	−100	−	mA
Isc6	short-circuit CANL current	V6 = 36 V	−	−	200	mA
DC bus receiver [V1 = 4 V; pins 6 and 7 externally driven; −2 V < (V6, V7) < 7 V; unless otherwise specified]
Vdiff(r)	differential input voltage	note 2	−1.0	−	+0.5	V
	(recessive)	−7 V < (V6, V7) < 12 V; note 2	−1.0	−	+0.4	V
Vdiff(d)	differential input voltage		0.9	−	5.0	V
	(dominant)	−7 V < (V6, V7) < 12 V; not	1.0	−	5.0	V
		standby mode
		standby mode	0.97	−	5.0	V
		standby mode;	0.91	−	5.0	V
		VCC = 4.5 to 5.10 V
Vdiff(hys)	differential input hysteresis	see Fig.5	−	150	−	mV

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