XL2551

XD2551 DIP8 / XL2551 SOP8 Features TXD 1 8 RS VSS 2 7 CANH VDD 3 6 CANL RXD 4 5 VREF 2551 • Suitable for 12V and 24V systems • Externally-controlled slope for reduced RFI emissions • Detection of ground fault (permanent Dominant) on TXD input • Power-on Reset and voltage brown-out protection • An unpowered node or brown-out event will not disturb the CAN bus • Low current standby operation • Protection against damage due to short-circuit conditions (positive or negative battery voltage) • Protection against high-voltage transients • Automatic thermal shutdown protection • Up to 112 nodes can be connected • High-noise immunity due to differential bus implementation • Temperature ranges: - Industrial (I): -40°C to +85°C - Extended (E): -40°C to +125°C Block Diagram VDD TXD Dominant Detect VDD Driver Control TXD RS Slope Control Power-On Reset RXD VREF Thermal Shutdown CANH 0.5 VDD GND Reference Voltage CANL Receiver VSS 1 XD2551 DIP8 / XL2551 SOP8 TABLE 1-1: MODES OF OPERATION Mode Current at Rs Pin Standby Slope-Control High-Speed TABLE 1-2: Resulting Voltage at RS Pin -IRS < 10 µA 10 µA < -IRS < 200 µA -IRS < 610 µA VRS > 0.75 VDD 0.4 VDD < VRS < 0.6 VDD 0 < VRS < 0.3VDD TRANSCEIVER TRUTH TABLE VDD VRS TXD CANH CANL Bus State( 1) HIGH LOW Dominant Not Driven Not Driven Recessive VRS > 0.75 VDD Not Driven Not Driven Recessive HIGH LOW Dominant VRS < 0.75 VDD VPOR < VDD < 4.5V Not Driven Not Driven Recessive (See Note 3) VRS > 0.75 VDD Not Driven Not Driven Recessive Not Driven/ Not Driven/ 0 < VDD < VPOR X X High Impedance No Load No Load Note 1: If another bus node is transmitting a Dominant bit on the CAN bus, then RXD is a logic ‘0’. 2: X = “don’t care”. 3: Device drivers will function, although outputs are not ensured to meet the ISO-11898 specification. VRS < 0.75 VDD 4.5V ≤ VDD ≤ 5.5V FIGURE 1-1: 0 1 or floating X 0 1 or floating X SLEW RATE VS. SLOPE-CONTROL RESISTANCE VALUE 25 Slew Rate V/μs 20 15 10 5 0 10 20 30 40 49 60 70 76 Resistance (k) 2 90 100 110 120 RXD( 1) 0 1 1 0 1 1 X XD2551 DIP8 / XL2551 SOP8 1.0 TXD Permanent Dominant Detection 1.2.1 TXD is a TTL-compatible input pin. The data on this pin is driven out on the CANH and CANL differential output pins. It is usually connected to the transmitter data output of the CAN controller device. When TXD is Low, CANH and CANL are in the Dominant state. When TXD is High, CANH and CANL are in the Recessive state, provided that another CAN node is not driving the CAN bus with a Dominant state. TXD has an internal pull-up resistor (nominal 25 kΩ to VDD). If the 2551 detects an extended Low state on the TXD input, it will disable the CANH and CANL output drivers in order to prevent the corruption of data on the CAN bus. The drivers are disabled if TXD is Low for more than 1.25 ms (minimum). This implies a maximum bit time of 62.5 µs (16 kb/s bus rate), allowing up to 20 consecutive transmitted Dominant bits during a multiple bit error and error frame scenario. The drivers remain disabled as long as TXD remains Low. A rising edge on TXD will reset the timer logic and enable the CANH and CANL output drivers. 1.1 1.2.2 GROUND SUPPLY (VSS) Ground supply pin. 1.2.3 Power-on Reset SUPPLY VOLTAGE (VDD) Positive supply voltage pin. When the device is powered on, CANH and CANL remain in a high-impedance state until VDD reaches the voltage-level VPORH. In addition, CANH and CANL will remain in a high-impedance state if TXD is Low when VDD reaches VPORH. CANH and CANL will become active only after TXD is asserted High. Once powered on, CANH and CANL will enter a high-impedance state if the voltage level at VDD falls below VPORL, providing voltage brown-out protection during normal operation. 1.2 TRANSMITTER DATA INPUT (TXD) 1.2.4 RECEIVER DATA OUTPUT (RXD) RXD is a CMOS-compatible output that drives High or Low depending on the differential signals on the CANH and CANL pins and is usually connected to the receiver data input of the CAN controller device. RXD is High when the CAN bus is Recessive and Low in the Dominant state. 1.2.5 Pin Descriptions REFERENCE VOLTAGE (VREF) Reference Voltage Output (defined as VDD/2). The 8-pin pinout is listed in Table 1-3. 1.2.6 TABLE 1-3: MCP2551 PINOUT CAN LOW (CANL) The CANL output drives the Low side of the CAN differential bus. This pin is also tied internally to the receive input comparator. Pin Number Pin Name 1 TXD Transmit Data Input 1.2.7 2 VSS Ground 3 VDD Supply Voltage 4 RXD Receive Data Output The CANH output drives the high-side of the CAN differential bus. This pin is also tied internally to the receive input comparator. 5 VREF Reference Output Voltage 1.2.8 6 CANL CAN Low-Level Voltage I/O 7 CANH CAN High-Level Voltage I/O The RS pin is used to select High-Speed, Slope-Control or Standby modes via an external biasing resistor. 8 RS Pin Function Slope-Control Input 3 CAN HIGH (CANH) SLOPE RESISTOR INPUT (RS) XD2551 DIP8 / XL2551 SOP8 2.0 ELECTRICAL CHARACTERISTICS 2.1 Terms and Definitions 2.1.5 Differential voltage of the two-wire CAN bus, value VDIFF = VCANH - VCANL. 2.1.6 A number of terms are defined in ISO-11898 that are used to describe the electrical characteristics of a CAN transceiver device. These terms and definitions are summarized in this section. 2.1.1 BUS VOLTAGE 2.1.7 INTERNAL RESISTANCE, RIN (OF A CAN NODE) Resistance seen between CANL (or CANH) and ground during the Recessive state when the CAN node is disconnected from the bus (see Figure 2-1). COMMON MODE BUS VOLTAGE RANGE Boundary voltage levels of VCANL and VCANH with respect to ground, for which proper operation will occur, if up to the maximum number of CAN nodes are connected to the bus. 2.1.3 INTERNAL CAPACITANCE, CIN (OF A CAN NODE) Capacitance seen between CANL (or CANH) and ground during the Recessive state when the CAN node is disconnected from the bus (see Figure 2-1). VCANL and VCANH denote the voltages of the bus line wires CANL and CANH relative to ground of each individual CAN node. 2.1.2 DIFFERENTIAL VOLTAGE, VDIFF (OF CAN BUS) FIGURE 2-1: PHYSICAL LAYER DEFINITIONS ECU DIFFERENTIAL INTERNAL CAPACITANCE, CDIFF (OF A CAN NODE) RIN Capacitance seen between CANL and CANH during the Recessive state when the CAN node is disconnected from the bus (see Figure 2-1). RIN CANL CANH CIN 2.1.4 CDIFF RDIFF DIFFERENTIAL INTERNAL RESISTANCE, RDIFF (OF A CAN NODE) CIN GROUND Resistance seen between CANL and CANH during the Recessive state when the CAN node is disconnected from the bus (see Figure 2-1). 4 XD2551 DIP8 / XL2551 SOP8 Absolute Maximum Ratings† VDD .............................................................................................................................................................................7.0V DC Voltage at TXD, RXD, VREF and VS ............................................................................................ -0.3V to VDD + 0.3V DC Voltage at CANH, CANL (Note 1) .......................................................................................................... -42V to +42V Transient Voltage on Pins 6 and 7 (Note 2) ............................................................................................. -250V to +250V Storage temperature ...............................................................................................................................-55°C to +150°C Operating ambient temperature ..............................................................................................................-40°C to +125°C Virtual Junction Temperature, TVJ (Note 3).............................................................................................-40°C to +150°C Soldering temperature of leads (10 seconds) .......................................................................................................+300°C ESD protection on CANH and CANL pins (Note 4) ...................................................................................................6 kV ESD protection on all other pins (Note 4) ..................................................................................................................4 kV Note 1: Short-circuit applied when TXD is High and Low. 2: In accordance with ISO-7637. 3: In accordance with IEC 60747-1. 4: Classification A: Human Body Model. 5 XD2551 DIP8 / XL2551 SOP8 2.2 DC Characteristics Electrical Characteristics: Industrial (I): TAMB = -40°C to +85°C VDD = 4.5V to 5.5V Extended (E): TAMB = -40°C to +125°C VDD = 4.5V to 5.5V DC Specifications Param No. Sym Characteristic Min Max Units Conditions D1 — 75 mA Dominant; VTXD = 0.8V; VDD D2 — 10 mA Recessive; VTXD = +2V; RS = 47 kW — 365 µA -40°C ≤ TAMB ≤ +85°C, Standby; (Note 2) — 465 µA -40°C ≤ TAMB ≤ +125°C, Standby; (Note 2) Supply IDD Supply Current D3 D4 VPORH High-level of the Power-on Reset comparator 3.8 4.3 V CANH, CANL outputs are active when VDD > VPORH D5 VPORL Low-level of the Power-on Reset comparator 3.4 4.0 V CANH, CANL outputs are not active when VDD < VPORL D6 VPORD Hysteresis of Power-on Reset comparator 0.3 0.8 V Note 1 2.0 3.0 V VTXD = VDD; no load. -2 +2 mA -2V < V(CAHL,CANH) < +7V, 0V