MAX3140 19-1453 Rev 1 9/10 SPI/MICROWIRE-Compatible UART with Integrated True Fail-Safe RS-485/RS-422 Transceivers General Description Features The MAX3140 is a complete universal asynchronous Integrated UART and RS-485/RS-422 Transceiver receiver-transmitter (UART) and a true fail-safe RS- in a Single 28-Pin QSOP 485/RS-422 transceiver combined in a single 28-pin SPI/MICROWIRE-Compatible Interface Saves C QSOP package for space-, cost-, and power-con- I/O Pins strained applications. The MAX3140 saves additional True Fail-Safe Receiver Output Eliminates board space as well as microcontroller (C) I/O pins by Complex Network Termination featuring an SPI/QSPI/MICROWIRE-compatible serial interface. It is pin-programmable for configuration Pin-Programmable RS-485/RS-422 Features in all RS-485/RS-422 networks. Half/Full-Duplex Operation Slew-Rate Limiting for Reduced EMI The MAX3140 includes a single RS-485/RS-422 driver 115kbps/500kbps/10Mbps Data Rates and receiver featuring true fail-safe circuitry, which Receiver/Transmitter Phase for Twisted-Pair guarantees a logic-high receiver output when the Polarity Reversal receiver inputs are open or shorted. This feature pro- vides immunity to faults without requiring complex ter- Full-Featured UART mination. The MAX3140 provides software-selectable Programmable Up to 230k baud with a control of half- or full-duplex operation, data rate, slew 3.6864MHz Crystal rate, and transmitter and receiver phase. The RS-485 8-Word Receive FIFO Minimizes Processor driver slew rate is programmable to minimize EMI and Overhead results in maximum data rates of 115kbps, 500kbps, 9-Bit Address-Recognition Interrupt and 10Mbps. Independent transmitter/receiver phase Allows Up to 256 Transceivers on the Bus control enables software correction of twisted-pair Low 20A Hardware Shutdown Mode polarity reversal. A 1/8-unit-load receiver input imped- ance allows up to 256 transceivers on the bus. Hardware/Software-Compatible with MAX3100 and MAX3089 The MAX3140s UART includes an oscillator circuit derived from an external crystal, and a baud-rate gen- Ordering Information erator with software-programmable divider ratios for all common baud rates from 300 baud to 230k baud. The PART TEMP. RANGE PIN-PACKAGE UART features an 8-word-deep receive FIFO that mini- MAX3140CEI+ 0C to +70C 28 QSOP mizes processor overhead and provides a flexible inter- MAX3140EEI+ -40C to +85C 28 QSOP rupt with four maskable sources, including address +Denotes a lead(Pb)-free/RoHS-compliant package. recognition on 9-bit networks. Two control lines are included for hardware handshakingone input and Typical Application Circuit one output. The MAX3140 operates from a single +5V supply and typically consumes only 645A with the receiver active. Hardware-invoked shutdown reduces supply current to MAX3140 only 20A. The UART and RS-485/RS-422 functions can CONTROL RS-485 SPI/ be used together or independently since the two func- MICRO- LOGIC RS-422 WIRE tions share only supply and ground connections (the R t MAX3140 is hardware- and software-compatible with the CS MAX3100 and MAX3089). SCLK UART DIN P Applications DOUT Industrial-Control Transceivers for EMI- Local Area Networks Sensitive Applications IRQ HVAC and Building Control Embedded Systems R t Point-of-Sale Devices Intelligent Instrumentation SPI/QSPI are trademarks of Motorola, Inc. HALF/FULL-DUPLEX MICROWIRE is a trademark of National Semiconductor Corp. H/F SRLTXP RXP RS-485/RS-422 Pin Configuration appears at end of data sheet. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.SPI/MICROWIRE-Compatible UART with Integrated True Fail-Safe RS-485/RS-422 Transceivers ABSOLUTE MAXIMUM RATINGS V to GND ..........................................................................+6V X2, DOUT, IRQ Short-Circuit Duration CC Input Voltage to GND (CS, SHDN, X1, CTS, RX, DIN, SCLK, (to V or GND) ......................................................Continuous CC RE, DE, H/F, SRL, TXP, RXP, Dl) .............-0.3V to (V + 0.3V) Continuous Power Dissipation (T = +70C) CC A Output Voltage to GND 28-pin QSOP (derate 10.8mW/C above +70C)..........860mW DOUT, RTS, TX, X2, RO...........................-0.3V to (V + 0.3V) CC Operating Temperature Ranges IRQ ........................................................................-0.3V to +6V MAX3140CEI .......................................................0C to +70C Driver Output Voltage (Y, Z) ...............................................13V MAX3140EEI ....................................................-40C to +85C Receiver Input Voltage, Half Duplex (Y, Z)......................... 13V Storage Temperature Range .............................-65C to +150C Receiver Input Voltage, Full Duplex (A, B) .........................25V Lead Temperature (soldering, 10sec) .............................+300C TX, RTS Output Current ...................................................100mA Soldering Temperature (reflow) .......................................+260C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = +5V 5%, DE = V , RE = GND, SHDN = V , f = 1.8432MHz, T = T to T , unless otherwise noted. Typical values CC CC CC XTL A MIN MAX are measured with V = +5V, UART configured for 9600 baud, T = +25C.) (Note 1) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLY Supply Voltage V 4.75 5.25 V CC DE = V 0.7 1.9 CC SRL = V CC SHDN = V CC DE = GND 0.64 1.6 Supply Current I SHDNi bit = 0, mA CC DE = V 0.74 2 SRL = GND CC no load or open DE = GND 0.69 1.8 I Supply Current with Only UART CC SHDN SHDN = GND or SHDNi bit = 1 0.47 1 mA Shut Down UART Supply Current with Both I SHDN = GND or SHDNi bit = 1 CC SHDN RS-485 Transceiver and UART 20 A DE = GND RE = V (FULL) CC Shut Down UART OSCILLATOR INPUT (X1) Input High Voltage V 0.7V V IH1 CC Input Low Voltage V 0.2V V IL1 CC SHDNi bit = 0 25 Input Current I V = 0 or V A IN1 X1 CC SHDNi bit = 1 2 Input Capacitance C 5 pF IN1 UART LOGIC INPUTS (DIN, SCLK, CS, SHDN, CTS, RX) Input High Voltage V 0.7V V IH2 CC Input Low Voltage V 0.3V V IL2 CC Input Hysteresis V 250 mV HYST2 Input Leakage Current I 1 A LKG1 Input Capacitance C 5 pF IN2 UART OUTPUTS (DOUT, TX, RTS) I = 5mA DOUT, RTS V - 0.5 SOURCE CC Output High Voltage V V OH1 I = 10mA TX only V - 0.5 SOURCE CC I = 4mA DOUT, RTS 0.4 SINK Output Low Voltage V V OL1 I = 25mA TX only 0.9 SINK Output Leakage I CS = V D only 1 A LKG2 CC OUT Output Capacitance C 5 pF OUT1 2 MAX3140