Detailed Description

The MAX3053 interfaces between the protocol controller

and the physical wires of a CAN bus. It is primarily intend-

ed for industrial applications requiring data rates up to

2Mbps and features ±80V fault protection against shorts

in high-voltage systems. This fault protection allows the

device to withstand up to ±80V with respect to ground

with no damage to the device. The built-in fault tolerance

allows the device to survive in industrial and automotive

environments with no external protection devices. The

device provides differential transmit capability to the bus

and differential receive capability to the CAN controller

(Figure 4).

The device has three modes of operations: high-speed,

slope control, and shutdown. In high-speed mode, slew

rates are not limited, making 2Mbps transmission speeds

possible. Slew rates are controlled in slope control mode,

minimizing EMI and allowing use of unshielded twisted or

parallel cable. The device goes into low-power operation

in shutdown mode.

The transceiver is designed to operate from a single +5V

supply, and draws 56mA of supply current in dominant

state and 3.6mA in recessive state. In shutdown mode,

supply current is reduced to 15μA.

CANH and CANL are output short circuit current limited

and are protected against excessive power dissipation by

thermal-shutdown circuitry that places the driver outputs

into a high-impedance state.

Fault Protection

The MAX3053 features ±80V fault protection. This extend-

ed voltage range of CANH and CANL bus lines allows its

use in high-voltage systems and communicating to high-

voltage buses. If data is transmitting at 2Mbps, the fault

protection is reduced to ±70V.

Transmitter

The transmitter converts a single-ended input (TXD) from

the CAN controller to differential outputs for the bus lines

(CANH, CANL). Table 1 is the truth table for the transmit-

ter and receiver.

High Speed

Connect RS to ground to set the MAX3053 to highspeed

mode. When operating in high-speed mode, the MAX3053

can achieve transmission rates up to 2Mbps. Line drivers

are switched on and off as quickly as possible. However,

in this mode, no measures are taken to limit the rise and

fall slope of the data signal, allowing for potential EMI

emissions. If using the MAX3053 in high-speed mode,

use shielded twisted-pair cable to avoid EMI problems.

Figure 4. Block Diagram

THERMAL

SHUTDOWN

CANH

TXD

RS

RXD

CANL

GND

AUTOSHUTDOWN

TRANSMITTER

CONTROL

MODE

SELECTION

RECEIVER

WAKE

0.75V

7.5V

SHDN

MAX3053

MAX3053

±80V Fault-Protected, 2Mbps,

Low Supply Current CAN Transceiver

www.maximintegrated.com

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