±15kV ESD-Protected, +3.0V to +5.5V, 10nA, RS-232/RS-485/RS-422 Multiprotocol Transceivers

Transcription

1 9-358; Rev ; /5 EVALUATION KIT AVAILABLE ±5kV ESD-Protected, +3.V to +5.5V, na, General Description The are programmable RS-3/RS-485/RS-4 multiprotocol transceivers. The MAX36E/MAX36E are pin programmable as a Tx/Rx RS-3 interface or a single RS-485/RS-4 transceiver. The MAX36E is configured as a Tx/Rx RS-3 interface, and a single RS-485/RS-4 transceiver simultaneously. The feature enhanced electrostatic discharge (ESD) protection. All of the transmitter outputs and receiver inputs are protected to ±5kV using the Human Body Model. All devices incorporate a proprietary low-dropout transmitter output stage, and an on-board dual charge pump to allow RS-3- and RS-485-/RS-4-compliant performance from a +3V to +5.5V supply. The receivers feature true fail-safe circuitry that guarantees a logic-high receiver output when the receiver inputs are open or shorted. These devices also feature pin-selectable transmitter slew rates for RS-3 and RS-485/RS-4 modes. Slewrate limiting minimizes EMI and reduces reflections caused by improperly terminated cables, allowing errorfree data transmission up to 5kbps. Disabling slew-rate limiting allows these devices to transmit at data rates up to Mbps in RS-485/RS-4 mode and up to Mbps in RS-3 mode. The feature a na shutdown mode, short-circuit limiting, and thermal shutdown circuitry to protect against excessive power dissipation. The MAX36E/MAX36E offer a flow-through pinout that facilitates board layout. The MAX36E/ MAX36E/MAX36E are available in tiny SSOP packages and operate over the commercial and extended temperature ranges. Features Single Supply Operation from +3V to +5.5V ESD Protection ±5kV Human Body Model Pin-Selectable as Tx/Rx RS-3 or Single RS-485/RS-4 (MAX36E/MAX36E) Tx/Rx RS-3 and Single RS-485/RS-4 (MAX36E) Pin-Selectable RS-3/RS-485 Transmitter Slew Rates Reduce EMI Mbps RS-485 and Mbps RS-3 Data Rates Pin-Selectable Half-Duplex or Full-Duplex RS-485/RS-4 Operation (MAX36E/MAX36E) RS-485/RS-4 True Fail-Safe Receivers na Shutdown Supply Current /8-Unit Load Allows up to 56 Transceivers on the Bus PART TEMP RANGE Ordering Information Typical Operating Circuit +3V TO +5.5V PIN- PACKAGE PACKAGE CODE MAX36ECAP C to +7 C SSOP A- MAX36EEAP -4 C to +85 C SSOP A- MAX36ECAG C to +7 C 4 SSOP A4-3 MAX36EEAG -4 C to +85 C 4 SSOP A4-3 MAX36ECAI C to +7 C 8 SSOP A8- MAX36EEAI -4 C to +85 C 8 SSOP A8- Applications Point-of-Sales Equipment Peripherals Industrial Controls Networking RS-3 to RS-485 Security Systems Interface Converters RS-485/RS3 MAX36E TX DI/TIN Z(B)/TOUT RTS DE485/TIN Y(A)/TOUT 5 6 MAX3 RX RO/ROUT A/RIN 8 3 DB9 CTS SPI ROUT B/RIN 7 4 GND FAST HDPLX 4 9 RJ45 µp Pin Configurations appear at end of data sheet. Selector Guide appears at end of data sheet. Maxim Integrated Products For price, delivery, and to place orders, please contact Maxim Distribution at , or visit Maxim s website at

2 ABSOLUTE MAXIMUM RATINGS to GND...-.3V to +6V V+ to GND...-.3V to +7V V- to GND....-7V to +.3V V+ - V- (Note )...+3V Input Voltages TIN, TIN, DI, DE485, RE485, TE3, RE3,, FAST, HDPLX, RS485/RS3 to GND V to +6V A, B, RIN, RIN to GND...±5V Output Voltages TOUT, TOUT, Y, Z to GND ( = or = GND)...±3.V TOUT, TOUT to GND ( = 5.5V and = )...-3.V to +9V ROUT, ROUT, RO to GND...-.3V to ( +.3V) ELECTRICAL CHARACTERISTICS Output Short-Circuit Duration TOUT, TOUT, Y, Z...Continuous Continuous Power Dissipation (T A = +7 C) -Pin SSOP (derate 8.mW/ C above +7 C)...64mW 4-Pin SSOP (derate 8.mW/ C above +7 C)...64mW 8-Pin SSOP (derate 9.mW/ C above +7 C)...77mW Operating Temperature Ranges MAX36_CA_... C to +7 C MAX36_EA_...-4 C to +85 C Storage Temperature Range C to +5 C Junction Temperature...+5 C Lead Temperature (soldering, s)...+3 C Note : V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 3V. 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. ( = +3V to +5.5V, C C4 =.µf when tested at +3.3V ±%; C =.47µF and C, C3, C4 =.33µF when tested at +5V±%; T A = T MIN to T MAX, unless otherwise noted. Typical values are at = +3.3V and T A = +5 C.) (Note ) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC CHARACTERISTICS Standby Current I CC MAX36E/MAX36E, no load, RS-485/ RS-3 = GND..8 MAX36E/MAX36E, no load, RS-485/ RS-3 = MAX36E, no load 3 6 Shutdown Current I = GND, receiver inputs open or grounded ma. µa TRANSMITTER AND (DI, TIN, TIN, DE485, RE485, TE3, RE3, FAST, HDPLX,, RS-485/ RS-3 ) Logic-Input Low V IL.8 V = +3.3V. Logic-Input High V IH = +5V.4 V Logic-Input Leakage Current I INL ±. ± µa Transmitter Logic Hysteresis V HYS.5 V RS-3 AND RS-485/RS-4 RECEIVER (ROUT, ROUT, RO) Receiver Output-Voltage Low V OL I OUT =.5mA.4 V Receiver Output-Voltage High V OH I OUT = -.5mA -.6 V Receiver Output Short-Circuit Current I OSR V O ± ±85 ma Receiver Output Leakage Current I OZR Receivers disabled ±.5 ± µa

3 ELECTRICAL CHARACTERISTICS (continued) ( = +3V to +5.5V, C C4 =.µf when tested at +3.3V ±%; C =.47µF and C, C3, C4 =.33µF when tested at +5V±%; T A = T MIN to T MAX, unless otherwise noted. Typical values are at = +3.3V and T A = +5 C.) (Note ) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RS-3 RECEIVER (RIN, RIN) Input Voltage Range V Logic-Input Low.8 Logic-input High = +3.3V. = +5V.4 Input Hysteresis.5 V Input Resistance RS-485/RS-4 RECEIVER (Note 3) = +3.V to 5.5V = 6 6 MAX36E 48 Input Resistance R IN -7V < V CM < +V MAX36E/ MAX36E V CM = +V.5 MAX36E V CM = -7V -.5 Input Current I IN ma V CM = +V.5 MAX36E/MAX36E V CM = -7V -.75 Input Differential Threshold V TH -7V V CM +V - -5 mv Input Hysteresis V TH 3 mv RS-3 TRANSMITTER (TOUT, TOUT) Output Voltage Swing Both transmitter outputs loaded with 3kΩ to GND 96 V kω kω ±5 ±5.4 V Output Resistance = V+ = V- =, T_OUT = ±V 3 M Ω Output Short-Circuit Current I SC T_OUT = GND ±3 ±6 ma Output Leakage Current I O TE3 = GND or = MAX36E ±5 V OUT = ±9V MAX36E ±5 GND MAX36E ±5 RS-485/RS-4 TRANSMITTER (Y, Z) Differential Output Voltage V OD Figure R = 7Ω (RS-485) R = 5Ω (RS-4).5 µa V Change in Magnitude of Differential Output Voltage for Complementary Output States V OD R = 7Ω or 5Ω, Figure. V Common-Mode Output Voltage V OC R = 7Ω or 5Ω, Figure 3 V Change in Magnitude of Common-Mode Output Voltage for Complementary Output States V OC R = 7Ω or 5Ω, Figure. V 3

4 ELECTRICAL CHARACTERISTICS (continued) ( = +3V to +5.5V, C C4 =.µf when tested at +3.3V ±%; C =.47µF and C, C3, C4 =.33µF when tested at +5V±%; T A = T MIN to T MAX, unless otherwise noted. Typical values are at = +3.3V and T A = +5 C.) (Note ) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Output Short-Circuit Current I SC V Y or V Z = -7V to +V ±5 ma Output Leakage Current IO V Y or V Z = -7V or +V, MAX36E ±5 DE485 = GND or = MAX36E ±5 GND MAX36E ±5 RS-3 TRANSMITTER TIMING CHARACTERISTICS (SLOW MODE, FAST = GND, 5kbps, one transmitter switching) Maximum Data Rate R L = 3kΩ, C L = pf 5 kbps Transmitter Skew t TSKEW R L = 3kΩ, C L = 5pF, Figure 6 5 ns Transition-Region Slew Rate = +3.3V, T A = +5 C, R L = 3kΩ to 7kΩ, measured from +3.V to -3.V or -3.V to +3.V C L = 5pF to pf C L = 5pF to 5pF RS-3 TRANSMITTER TIMING CHARACTERISTICS (FAST MODE, FAST =, Mbps, one transmitter switching) Maximum Data Rate = +3V to +4.5V, R L = 3kΩ, C L = 5pF = +4.5V to +5.5V, R L = 3kΩ, C L = pf Transmitter Skew t TSKEW R L = 3kΩ, C L = 5pF, Figure 6 ns Transition-Region Slew Rate RS-3 RECEIVER TIMING CHARACTERISTICS = +3.3V, T A = +5 C, R L = 3kΩ to 7kΩ, C L = 5pF to pf, measured from +3.V to -3.V or -3.V to +3.V MAX36E 3 5 MAX36E MAX36E 4 5 Receiver Propagation Delay t PHL,t PLH R_IN to R_OUT, C L = 5pF, Figure 5.5 µs Receiver Output Enable Time t RZL,t RZH C L = 5pF, Figures,, MAX36E ns Receiver Output Disable Time t RLZ,t RHZ C L = 5pF, Figures,, MAX36E ns Receiver Skew t RSKEW C L = 5pF, Figure 5 ns RS-485/RS-4 DRIVER TIMING CHARACTERISTICS (SLOW MODE, FAST = GND, 5kbps) Differential Driver Propagation Delay Differential Driver Rise and Fall Time Differential Driver Propagation Delay Skew t DPHL, t DPLH R DIFF = 54Ω, C L = 5pF, Figures 3, ns µa V/µs Mbps t DR, t DF R DIFF = 54Ω, C L = 5pF, Figures 3, ns t DSKEW R DIFF = 54Ω, C L = 5pF, Figures 3, 7 ns Driver Output Enable Time t DZH, t DZL C L = 5pF, Figures 4, ns Driver Output Disable Time t DLZ, t DHZ C L = 5pF, Figures 4, 8 4 ns V/µs 4

5 ELECTRICAL CHARACTERISTICS (continued) ( = +3V to +5.5V, C C4 =.µf when tested at +3.3V ±%; C =.47µF and C, C3, C4 =.33µF when tested at +5V±%; T A = T MIN to T MAX, unless otherwise noted. Typical values are at = +3.3V and T A = +5 C.) (Note ) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RS-485/RS-4 DRIVER TIMING CHARACTERISTICS FAST MODE, FAST =, Mbps) Differential Driver Propagation Delay Differential Driver Rise and Fall Times t DPHL, t DPLH R DIFF = 54Ω, C L = 5pF, Figures 3, 7 6 ns t DR, t DF R DIFF = 54Ω, C L = 5pF, Figures 3, 7 5 ns Differential Driver Propagation Delay Skew t DSKEW R DIFF = 54Ω, C L = 5pF, Figures 3, 7 ns Driver Output Enable Time t DZH,t DZL C L = 5pF, Figures 4, ns Driver Output Disable Time t DHZ,t DLZ C L = 5pF, Figures 4, 8 4 ns RS-485/RS-4 RECEIVER TIMING CHARACTERISTICS Receiver Propagation Delay t RPLH, t RPHL C L = 5pF, Figures 9, 8 5 ns Receiver Propagation Delay Skew t RSKEW C L = 5pF, Figures 9, ns Receiver Output Enable Time t RZL, t RZH MAX36E, C L = 5pF, Figures, ns Receiver Output Disable Time t RLZ, t RHZ MAX36E, C L = 5pF, Figures, ns ESD PROTECTION R_IN, T_OUT, A, B, Y, Z Human Body Model ±5 kv Note : All currents into the device are positive. All currents out of the device are negative. Note 3: Applies to A, B for MAX36E and MAX36E/MAX36E with HDPLX = GND, or Y, Z for MAX36E/MAX36E with HDPLX =. Typical Operating Characteristics ( = +3.3V, 5kbps data rate, C BYPASS, C, C, C3, C4 =.µf, all RS-3 transmitters (RS-3 mode) loaded with 3kΩ to ground, T A = +5 C, unless otherwise noted.) TRANSMITTER OUTPUT VOLTAGE (V) RS-3 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (FAST = GND) MAX36E toc TRANSMITTER OUTPUT VOLTAGE (V) RS-3 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (FAST = ) DATA RATE = Mbps MAX36E toc SLEW RATE (V/µs) RS-3 TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE (FAST = GND) FALLING RISING MAX36E toc LOAD CAPACITANCE (pf) LOAD CAPACITANCE (pf) LOAD CAPACITANCE (pf) 5

6 Typical Operating Characteristics (continued) ( = +3.3V, 5kbps data rate, C BYPASS, C, C, C3, C4 =.µf, all RS-3 transmitters (RS-3 mode) loaded with 3kΩ to ground, T A = +5 C, unless otherwise noted.) SLEW RATE (V/µs) SHUTDOWN CURRENT (na) RS-3 TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE (FAST = ) RISING FALLING LOAD CAPACITANCE (pf) SHUTDOWN CURRENT vs. TEMPERATURE MAX36E toc4 MAX36E toc7 SUPPLY CURRENT (ma) OUTPUT CURRENT (ma) OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA (RS-3 MODE) DATA RATE = Mbps DATA RATE = 5kbps DATA RATE = kbps LOAD CAPACITANCE (pf) RS-485/RS-4 OUTPUT CURRENT vs. DRIVER-OUTPUT LOW VOLTAGE MAX36E to5 MAX36E toc8 SUPPLY CURRENT (ma) OUTPUT CURRENT (ma) MAX36E/MAX36E NO-LOAD SUPPLY CURRENT vs. TEMPERATURE RS-485 MODE RS-3 MODE TEMPERATURE ( C) RS-485/RS-4 OUTPUT CURRENT vs. DRIVER-OUTPUT LOW VOLTAGE MAX36E toc6 MAX36E toc TEMPERATURE ( C) OUTPUT LOW VOLTAGE (V) OUTPUT LOW VOLTAGE (V) OUTPUT CURRENT (ma) RS-485/RS-4 DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE MAX36E toc OUTPUT VOLTAGE (V) RS-485/RS-4 DRIVER DIFFERENTIAL OUTPUT vs. TEMPERATURE R DIFF = Ω FIGURE MAX36E toc OUTPUT CURRENT (ma) RECEIVER OUTPUT CURRENT vs. RECEIVER- OUTPUT LOW VOLTAGE MAX36E toc OUTPUT LOW VOLTAGE (V) TEMPERATURE ( C) OUTPUT LOW VOLTAGE (V) 6

7 Typical Operating Characteristics (continued) ( = +3.3V, 5kbps data rate, C BYPASS, C, C, C3, C4 =.µf, all RS-3 transmitters (RS-3 mode) loaded with 3kΩ to ground, T A = +5 C, unless otherwise noted.) OUTPUT CURRENT (ma) PROPAGATION DELAY (ns) RECEIVER OUTPUT CURRENT vs. RECEIVER-OUTPUT HIGH VOLTAGE OUTPUT-HIGH VOLTAGE (V) RS-485/RS-4 DRIVER PROPAGATION DELAY vs. TEMPERATURE (FAST = GND) RISING FALLING C L = 5pF R DIFF = 54Ω DATA RATE = 5kbps TEMPERATURE ( C) MAX36E toc3 MAX36E toc6 PROPAGATION DELAY (ns) RS-485/RS-4 RECEIVER PROPAGATION DELAY vs. TEMPERATURE RISING FALLING TEMPERATURE ( C) RS-485/RS-4 DRIVER PROPAGATION (FAST =, Mbps) C L = 5pF R DIFF = 54Ω ns/div MAX36E toc7 MAX36E toc4 DI V/div V Y - V Z V/div PROPAGATION DELAY (ns) RS-485/RS-4 DRIVER PROPAGATION DELAY vs. TEMPERATURE (FAST = ) C L = 5pF R DIFF = 54Ω DATA RATE = Mbps RISING FALLING TEMPERATURE ( C) RS-485/RS-4 DRIVER PROPAGATION (FAST = GND, 5kbps) C L = 5pF R DIFF = 54Ω.µs/div MAX36E toc8 MAX36E toc5 DI V/div V Y - V Z V/div OUTPUT CURRENT (µa) I-V OUTPUT IMPEDANCE CURVE IN RS-3 SHUTDOWN MODE MAX36E toc9 RS-485/RS-4 RECEIVER PROPAGATION (FAST =, 5Mbps) C L = 5pF MAX36E toc V Y - V Z V/div RO V/div RS-485/RS-4 RECEIVER PROPAGATION (FAST =, 5Mbps) C L = 5pF R DIFF = 54Ω MAX36E toc DE485 V/div V Y - V Z V/div OUTPUT VOLTAGE (V) 4ns/div ns/div 7

8 Typical Operating Characteristics (continued) ( = +3.3V, 5kbps data rate, C BYPASS, C, C, C3, C4 =.µf, all RS-3 transmitters (RS-3 mode) loaded with 3kΩ to ground, T A = +5 C, unless otherwise noted.) MAX36E RS-3 TRANSMITTER PROPAGATION (FAST = GND, 5kbps) C L = pf R L = 7kΩ.µs/div MAX36E toc MAX36E/MAX36E RS-3 TRANSMITTER PROPAGATION (FAST = GND, 5kbps) C L = pf R L = 7kΩ MAX36E toc4 DI V/div T_OUT 5V/div DI V/div T_OUT 5V/div MAX36E RS-3 TRANSMITTER PROPAGATION (FAST =, 5kbps) C L = 5pF R L = 7kΩ.µs/div MAX36E toc3 MAX36E/MAX36E RS-3 TRANSMITTER PROPAGATION (FAST =, 5kbps) C L = 5pF R L = 7kΩ MAX36E toc5 DI V/div T_OUT 5V/div DI V/div T_OUT 5V/div.µs/div.µs/div TRANSMITTER OUTPUT VOLTAGE (V) TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (FAST = GND) AT AND GND TRANSMITTERS LOADED WITH 3kΩ SUPPLY VOLTAGE (V) MAX36E toc6 SUPPLY CURRENT (ma) SUPPLY CURRENT vs. SUPPLY VOLTAGE WITH RS-3 RUNNING (FAST = GND) C L = 5pF R L = 3kΩ TRANSMITTER AT 5kbps SUPPLY VOLTAGE (V) MAX36E toc7 8

9 PIN MAX36E MAX36E MAX36E NAME FUNCTION C+ Positive Terminal of the Positive Flying Capacitor Positive Supply Voltage C- Negative Terminal of the Positive Flying Capacitor GND Ground 5 5 TOUT RS-3 Driver Output 5 Z(B)/TOUT Pin Description Inverting RS-485/RS-4 Driver Output in Full-Duplex Mode (and Inverting RS-485/RS-4 Receiver Input in Half-Duplex Mode)/RS-3 Driver Output 6 Z Inverting RS-485/RS-4 Driver Output 6 Z(B) 6 Y(A)/TOUT Inverting RS-485/RS-4 Driver Output in Full-Duplex Mode (and Inverting RS-485/RS-4 Receiver Input in Half-Duplex Mode) Noninverting RS-485/RS-4 Driver Output in Full-Duplex Mode (and Noninverting RS-485/RS-4 Receiver Input in Half-Duplex Mode)/RS-3 Driver Output 7 Y Noninverting RS-485/RS-4 Driver Output 7 Y(A) Noninverting RS-485/RS-4 Driver Output in Full-Duplex Mode (and Noninverting RS-485/RS-4 Receiver Input in Half-Duplex Mode) ROUT RS-3 Receiver Output 8 8 TOUT RS-3 Driver Output 8 RO/ROUT RS-485/RS-4 Receiver Output/RS-3 Receiver Output 9 3 Active-Low Shutdown-Control Input. Drive low to shut down transmitters and charge pump. ROUT RS-3 Driver Output 4 FAST Transmitter Speed-Select Input. Select slew-rate limiting for RS-3 and RS-485/RS-4. Slew-rate limits with a logic-level low. RO RS-485/RS-4 Receiver Output 3 RS - 485/RS - 3 Pin-Selectable Mode Functionality Input. Operates as RS-485/RS-4 with a logic-level high; operates as RS-3 with a logic-level low. RE485 4 HDPLX RS-485/RS-4 Receiver Enable Input. Logic-level low enables RS-485/RS-4 receivers. Pin-Selectable Mode Functionality Input. Operates in fullduplex mode when low; operates in half-duplex mode when high. 9

10 PIN MAX36E MAX36E MAX36E NAME 3 A/RIN Pin Description (continued) FUNCTION Noninverting RS-485/RS-4 Receiver Input/RS-3 Receiver Input 4 B/RIN Inverting RS-485/RS-4 Receiver Input/RS-3 Receiver Input 5 RE3 RS-3 Receiver Enable. Logic-level low enables RS-3 receivers. 5 7 A Noninverting RS-485/RS-4 Receiver Input 5 9 DE485/TIN RS-485/RS-4 Driver Enable/RS-3 Driver Input 6 TE3 RS-3 Transmitter Output Enable 6 8 B Inverting RS-485/RS-4 Receiver Input 6 DI/TIN RS-485/RS-4 Driver Input/RS-3 Driver Input 7 9 RIN RS-3 Receiver Input 7 5 V- Negative Charge-Pump Rail 8 RIN RS-3 Receiver Input 8 6 C- Negative Terminal of the Negative Flying Capacitor C+ Positive Terminal of the Negative Flying Capacitor 4 8 V+ Positive Charge-Pump Rail TIN RS-3 Driver Input DE485 RS-485/RS-4 Driver Enable Input 3 DI RS-485/RS-4 Driver Input 4 TIN RS-3 Driver Input

11 C+ C C BYPASS RS GND ESD PROTECTION FAST RS-3 MODE T T R R CHARGE PUMP MAX36E ESD PROTECTION V+ C+ V- HDPLX RS-485/RS C3 C C4 RS-3 MAX36E Functional Diagram C+ C RS-485 C+ 9 C- 8 V- 7 C- 3 C BYPASS GND 4 OUTPUT R Z Y FAST R RS-485 MODE ESD PROTECTION CHARGE PUMP MAX36E D DE485 ESD PROTECTION V+ RS-485/RS-3 C- C- B A HDPLX C4 C3 RS-485 INPUT C

12 C+ C C BYPASS RS-3 OUTPUT RS-3 OUTPUT C- C- GND FAST ESD PROTECTION RS-3 MODE T T R R CHARGE PUMP MAX36E ESD PROTECTION V+ C+ C+ C 3 C- C BYPASS 4 GND V- HDPLX RS-485/RS C3 C C4 RS-3 MAX36E Functional Diagram C+ 3 C- V- RS-485 OUTPUT R FAST Z Y R ESD PROTECTION RS-485 MODE CHARGE PUMP D DE485 ESD PROTECTION V+ 4 B A HDPLX 4 MAX36E RS-485/RS-3 3 C3 C4 C RS-485 INPUT

13 MAX36E Functional Diagram C+ C C BYPASS RS-3 OUTPUT RS-485 RS-3 OUTPUT INPUT C+ 7 C- 6 V- 5 C- GND Z Y RO RE485 FAST ESD PROTECTION R R CHARGE PUMP D R MAX36E T DE485 T ESD PROTECTION TE3 V+ 8 RE B 8 A C3 C C4 RS-3 RS-485 RECEIVER OUTPUT DE485 DI Y Z TEST POINT C L 3V V OD Figure. RS-485/RS-4 Driver DC Test Load Y Z k V OD R DIFF S C L kω Figure. RS-485/RS-4 and RS-3 Receiver Enable/Disable Timing Test Load R R Test Circuits V OC S Figure 3. RS-485/RS-4 Driver Timing Test Circuit OUTPUT UNDER TEST 5Ω C L S S Figure 4. RS-485/RS-4 Driver Enable/Disable Timing Test Load 3

14 INPUT OUTPUT t PHL V +3V.5V 5% t RSKEW = t PLH - t PHL.5V 5% GND Figure 5. RS-3 Receiver Propagation-Delay Timing 3V DI Z Y V O V DIFF -V O V O.5V / V O t DR % t DPLH t DPHL.5V V DIFF = V y - V z 9% 9% t DF t DSKEW = t DPLH - t DPHL Figure 7. RS-485/RS-4 Driver Propagation Delays V OH RO V OL V -V A B / OUTPUT / t RPHL t RPLH INPUT t RSKEW = t RPLH - t RPHL tplh / V O % INPUT +3V OUTPUT t PLH Test Circuits (continued).5v.5v V t SKEW = t PLH - t PHL Figure 6. RS-3 Transmitter Propagation-delay Timing 3V DE485 Y, Z V OL Y, Z.5V.5V.3V OUTPUT NORMALLY LOW.3V t DZL t DZH t DLZ OUTPUT NORMALLY HIGH t DHZ t PHL V OL +.5V V OH -.5V Figure 8. RS-485/RS-4 Driver Enable and Disable Times 3V RE3 OR RE485 RO RO.5V.5V.5V OUTPUT NORMALLY LOW.5V t RZL t RZH t RLZ OUTPUT NORMALLY HIGH t RHZ V+ V V- V OL +.5V V OH -.5V Figure 9. RS-485/RS-4 Receiver Propagation Delays Figure. MAX36 RS-485/RS-4 and RS-3 Receiver Enable and Disable Times B V ID R RO A C L Figure. RS-485/RS-4 Receiver Propagation Delays Test Circuit 4

15 Detailed Description The +3V to +5.5V, multiprotocol transceivers can be pin-configured in a number of RS-3 and RS-485/RE-4 interface combinations. These circuit configurations are ideal for the design of RS-3 to RS-485 converters, multiprotocol buses, or any application that requires both RS-3 and RS-485 transceivers. The slew rate of these devices is on-the-fly pin selectable, allowing reduced EMI data rates, or up to Mbps RS-485 communications. Power consumption can be reduced to na by using the shutdown function, but the RS-3 receivers remain active allowing other devices to query the interface controller. A flow-through pinout and the space-saving SSOP packages (available in commercial and extended temperature ranges) facilitate board layout. Device Selection The contain RS-3 transceivers and an RS-485/RS-4 transceiver. The primary difference between the devices is the multiplexing of the I/O ports. The MAX36E has common transmitter outputs and receiver inputs for its RS-3 and RS-485/RS-4 transceivers, and common digital I/O ports. The MAX36E is optimized for multiprotocol operation on a single interface bus and comes in a -pin SSOP package. The MAX36E has separate transmitter outputs and receiver inputs for its RS-3 and RS-485/RS-4 transceivers, and common digital I/O ports. The MAX36E is optimized for multiplexing a single UART across two interface buses and is available in a 4-pin SSOP package. The MAX36E has separate transmitter outputs and receiver inputs for its RS-3 and RS-485/RS-4 transceivers, and separate digital I/O ports. The MAX36E is optimized for protocol translation between two interface buses and comes in a 8-pin SSOP package. See Tables, the Functional Diagrams, and the following descriptions for details on each device. MAX36E The MAX36E is a TX/RX RS-3 transceiver in RS-3 mode, capable of RS-3-compliant communication. Assertion of RS-485/RS-3 converts the device to a single RS-485 transceiver by multiplexing the RS- 3 I/O ports to an RS-485 driver and receiver pair. The logic inputs now control the driver input and the driver enable. One logic output carries the RS-485 receiver output, and the other is tri-stated. The receiver input impedance is dependent on the device mode and is /4-unit load for RS-485 operation and 5kΩ for RS-3 operation. MAX36E The MAX36E is a T X /R X RS-3 transceiver in RS-3 mode or a single RS-485/RS-4 transceiver in RS-485 mode. When in RS-485 mode, the unused RS- 3 transmitter and receiver outputs are disabled. When in RS-3 mode, the RS-485 transmitter outputs are disabled and the RS-3 receiver inputs are 5kΩ to GND. The RS-485 receiver inputs are always /8-unit load. Logic lines are shared between the two protocols and are used for signal inputs and as an RS-485 driver enable. MAX36E The MAX36E is a Tx/Rx RS-3 transceiver and a single RS-485/RS-4 transceiver simultaneously. All drivers, receivers, and transmitters can be enabled or disabled by pin selection. All outputs are high-impedance when not activated. RS-3 receiver inputs are 5kΩ when enabled, and RS-485 receiver inputs are /8-unit load. Fast-Mode Operation The FAST control input is used to select the slew-rate limiting of the RS-3 transmitters and the RS-485/ RS-4 drivers. With FAST unasserted, the RS-3 transmitters and the RS-485/RS-4 driver are slew-rate limited to reduce EMI. RS-3 data rates up to Mbps and RS-485/RS-4 data rates up to Mbps are possible when FAST is asserted. FAST can be changed during operation without interrupting data communications. Half-Duplex RS-485/RS-4 Operation Asserting HDPLX places the MAX36E/MAX36E in half-duplex mode. The RS-485 receiver inputs are internally connected to the driver outputs. To receive RS-485 data, disable the RS-485 outputs by driving DE485 low. HDPLX has no affect on RS-3 operation. Low-Power Shutdown The have an activelow shutdown control input,. When is driven low, the charge pump and transmitters are shut down and supply current is reduced to na. The RS-3 receiver outputs remain active if in RS-3 mode. The charge-pump capacitors must be recharged when coming out of shutdown before resuming operation in either RS-3 or RS-485/RS-4 mode (Figure ). Dual Charge-Pump Voltage Converter The s internal power supply consists of a regulated dual charge pump that provides output voltages of +5.5V (doubling charge pump), and -5.5V (inverting charge pump), for input voltages ( ) over the +3.V to +5.5V range. The charge pumps operate in a discontinuous mode. If the 5

16 magnitude of either output voltage is less than +5.5V, the charge pumps are enabled. If the magnitude of both output voltages exceeds +5.5V, the charge pumps are disabled. Each charge pump requires a flying capacitor (C, C) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies (see the Functional Diagrams). RS-485/RS-4 Transceivers The RS-485/RS-4 transceivers feature fail-safe circuitry that guarantees a logic-high receiver output when the receiver inputs are open or shorted, or when they are connected to a terminated transmission line with all drivers disabled (see the Fail-Safe Section). The MAX36E/MAX36E/ MAX36E also feature pin-selectable reduced slewrate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 5kbps The transmitters can operate at speeds up to Mbps with the slew-rate limiting disabled. Drivers are short-circuit current limited and thermally limited to protect them against excessive power dissipation. Half-duplex communication is enabled by driving HDPLX high (MAX36E/MAX36E.) Fail-Safe The guarantee a logic-high RS-485 receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. This is done by having the receiver threshold between -5mV and -mv. If the differential receiver input voltage (A-B) is greater than or equal to -5mV, RO is logic-high. If A-B is less than or equal to -mv, RO is logic-low. In the case of a terminated bus with all transmitters disabled, the receiver s differential input voltage is pulled to by the termination. This results in a logic-high with a 5mV minimum noise margin. The receivers convert RS-3 signals to CMOS-logic output levels. All receivers have inverting outputs that remain active in shutdown. The MAX36E/MAX36E/ MAX36E permit their receiver inputs to be driven to ±5V. Floating receiver input signals are pulled to ground through internal 5kΩ resistors, forcing the outputs to a logic-high. The MAX36E has transmitter and receiver enable pins that allow its outputs to be tri-stated. ±5kV ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against ESD encountered during handling and assembly. The MAX36E/ MAX36E/MAX36E receiver inputs and transmitter outputs have extra protection against static electricity found in normal operation. Maxim s engineers developed state-of-the-art structures to protect these pins against ±5kV ESD, without damage. After an ESD event, the continue working without latchup. The receiver inputs and transmitter outputs are characterized for ±5kV ESD protection using the Human Body Model ESD Test Conditions ESD performance depends on a number of conditions. Contact Maxim for a reliability report that documents test setup, methodology, and results. Human Body Model Figure 3a shows the Human Body Model, and Figure 3b shows the current waveform it generates when discharged into a low impedance. This model consists of a pf capacitor charged to the ESD voltage of interest, which is then discharged into the device through a.5kω resistor. RS-3 Transceivers The RS-3 transmitters are inverting-level translators that convert CMOS-logic levels to ±5V EIA/TIA-3-compliant levels. The transmitters are guaranteed at a 5kbps data rate in slew-rate limited mode (FAST = GND) with worst-case loads of 3kΩ in parallel with pf. Data rates up to Mbps can be achieved by asserting FAST. When powered down or in shutdown, the MAX36E/ MAX36E/MAX36E outputs are high impedance and can be driven to ±3.V. The transmitter inputs do not have pullup resistors. Connect unused inputs to ground or. 6

17 4µs/div 5V/div TOUT V/div Machine Model The Machine Model for ESD testing uses a pf storage capacitor and zero-discharge resistance. It mimics the stress caused by handling during manufacturing and assembly. Of course, all pins (not just RS-485 inputs) require this protection during manufacturing. Therefore, the Machine Model is less relevant to the I/O ports than are the Human Body Model and IEC -4-. Applications Information Capacitor Selection The capacitor type used for C C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. Ceramic chip capacitors with an X7R dielectric provide the best combination of performance, cost, and size. The charge pump requires.µf capacitors for 3.3V operation. For other supply voltages, see Table 3 for required capacitor values. Do not use values smaller than those listed in Table 3. Increasing the capacitor values reduces ripple on the transmitter outputs and slightly reduces power consumption. C, C3, and C4 can be changed without changing C s value. However, do not increase C without also increasing the values of C, C3, C4, and C BYPASS to maintain the proper ratios to the other capacitors. When using the minimum required capacitor values, make sure the capacitance value does not degrade excessively with temperature or voltage. This is typical of Y5V and Z5U dielectric ceramic capacitors. If in doubt, use capacitors with a larger nominal value. The capacitor s equivalent series resistance (ESR), which GND TOUT V/div Figure. RS-3 Transmitter Outputs when Exiting Shutdown HIGH- VOLTAGE DC SOURCE R C MΩ CHARGE-CURRENT LIMIT RESISTOR Cs pf R D.5kΩ DISCHARGE RESISTANCE STORAGE CAPACITOR Figure 3a. Human Body ESD Test Model AMPERES I P % 9% 36.8% % t RL TIME t DL CURRENT WAVEFORM Figure 3b. Human Body Model Current Waveform DEVICE UNDER TEST PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) usually rises at low temperatures, influences the amount of ripple on V+ and V-. Power-Supply Decoupling In applications that are sensitive to power-supply noise, decouple to ground with a capacitor of the same value as reservoir capacitors C, C3, and C4. Connect the bypass capacitor as close to the IC as possible. Ir 7

18 RS-3 Transmitter Outputs when Exiting Shutdown Figure shows two transmitter outputs when exiting shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-3 levels (one transmitter input is high, the other is low). Each transmitter is loaded with 3kΩ in parallel with pf. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown. Note that the transmitters are enabled only when V- exceeds approximately -3V. High Data Rates The maintain the RS-3 ±5V required minimum transmitter output voltage even at high data rates. Figure 4 shows a transmitter loopback test circuit. Figure 5 shows a loopback test result at 5kbps, and Figure 6 shows the same test at Mbps. Figure 5 demonstrates a single slew-rate limited transmitter driven at 5kbps (FAST = GND) into an RS-3 load in parallel with pf. Figure 7 shows a single transmitter driven at Mbps (FAST asserted), loaded with an RS-3 receiver in parallel with pf. These transceivers maintain the RS-3 ±5V minimum transmitter output voltage at data rates up to Mbps. 56 Transceivers on the Bus The standard RS-485 receiver input impedance is kω (one-unit load), and the standard driver can drive up to 3-unit loads. The MAX36E has a /4-unit load receiver input impedance (48kΩ), allowing up to 8 transceivers to be connected in parallel on one communication line. The MAX36E/MAX36E have a /8- unit load receiver input impedance (96kΩ), allowing up to 56 transceivers to be connected in parallel on one communication line. Any combination of these devices and/or other RS-485 transceivers with a total of 3-unit loads or fewer can be connected to the line. RS-485/RS-4 Driver Output Protection Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. The first, a foldback current limit on the output stage, provides immediate protection against short circuits over the whole common-mode voltage range (see the Typical Operating Characteristics). The second, a thermal shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature becomes excessive, typically over +5 C. Protection Against Wiring Faults EIA/TIA-485 standards require a common input voltage range of -7V to +V to prevent damage to the device. C C C BYPASS C+ C- C- C+ T_ IN R_ OUT MAX36E MAX36E MAX36E GND Figure 4. Loopback Test Circuit The inputs are protected to RS-3 levels of ±5V for the receiver inputs and ±3V for the transmitter/driver outputs. This provides additional protection for the RS-485 transceivers against ground differential or faults due to miswiring. RS-485/RS-4 Reduced EMI and Reflections The can be configured for slew-rate limiting by pulling FAST low. This minimizes EMI and reduces reflections caused by improperly terminated cables. Operation in slew-rate limited mode reduces the amplitudes of high-frequency harmonics. RS-485/RS-4 Line Length vs. Data Length The RS-485/RS-4 standard covers line lengths up to 4ft. For line lengths greater than 4ft, use the repeater application shown in Figure 7. RS-3/RS-485 Protocol Translator Figure 8 shows the MAX36E configured as an RS-3/RS-485 protocol translator. The direction of translation is controlled through the RTS signal (RIN). The single-ended RS-3 receiver input signal is translated to a differential RS-485 transmitter output. Similarly, a differential RS-485 receiver input signal is translated to a single-ended RS-3 transmitter output. RS-3 data received on R IN is transmitted as an RS- 485 signal on Z and Y. RS-485 signals received on A and B are transmitted as an RS-3 signal on TOUT. 5k V+ V- T_ OUT R_ IN C3 C4 pf 8

19 µs/div µs/div R OUT Multiprotocol Bus The Typical Operating Circuit shows a standard application for the MAX36E. The MAX36E s outputs are multiplexed between RS-3 and RS-485 protocols by a microprocessor (µp). The µp also directs the shutdown functions, enable lines, and the duplex of the MAX36E. Data is transmitted to the MAX3 UART through an SPI port. The UART asynchronously transfers data through the MAX36E to the pin-selected RS-3 or RS-485 protocal. See Table 4 for commonly used cable connections. T IN T OUT 5V/div R OUT Figure 5. MAX36E/MAX36E RS-3 Loopback Test Result at 5kbps, FAST = Low ns/div T OUT 5V/div R OUT Figure 6. MAX36E/MAX36E RS-3 Loopback Test Result at Mbps, FAST = High Multiprotocol Bus Multiplexer The Typical Application Circuit shows the MAX36E configured as a multiprotocol bus multiplexer. The MAX36E separates the RS-3 and RS-485 lines, but shares the logic pins between modes. This application allows the µp to monitor a point-to-point RS-3 bus, and a multidrop RS-485 interface. The MAX3 UART asynchronously transfers data through the MAX36E to the pin-selected RS-3 or RS-485 protocol. T IN SPI is a registered trademark of Motorola, Inc. 9

20 RE485 DE485 RO DI MAX36E MAX36E MAX36E NOTE: RE485 ON MAX36E ONLY Figure 7. RS-485 Line Repeater D R A B Z Y Ω Ω DATA IN DATA OUT RCV TX RTS C nf C3 nf 7 C+ Figure 8. Protocol Translator 3.3V C+ 6 C- MAX36E C TOUT TIN 4 ROUT RO 9 3 DI ROUT RE485 9 RIN DE RIN RE3 TE3 FAST A B Z Y V+ V- GND C BYPASS nf C nf C4 nf

21 RS-3 Transmitters Truth Tables Table. MAX36E RS-485/ RS-3 DI/TIN, DE485/TIN Z(B)/TOUT, Y(A)/TOUT X X /8-unit load X RS-485 mode Table. MAX36E RS-485/ RS-3 DI/TIN, DE485/TIN TOUT, TOUT X X High-impedance X High-impedance Table 3. MAX36E TE3 TIN,TIN TOUT, TOUT X X High-impedance X X High-impedance Table 4. MAX36E RS-485/ RS-3 B/RIN, A/RIN ROUT, RO/ROUT X X X Inputs open X X RS-3 Receivers Truth Tables Table 5. MAX36E RS-485/ RS-3 RIN, RIN ROUT High-impedance, RO/ROUT in RS-485 mode ROUT, RO/ROUT X X X Inputs open X X Table 6. MAX36E ROUT High-impedance, RO/ROUT in RS-485 mode RE3 RIN, RIN ROUT, ROUT X X High-impedance X X X Inputs open

22 RS-485/RS-4 Drivers Truth Tables Table 7. MAX36E RS-485/RS-3 DE485/TIN DI/TIN Z(B)/TOUT Y(A)/TOUT X X X /8-unit load /8-unit load X /8-unit load /8-unit load X X X RS-3 mode Table 8. MAX36E RS-485/RS-3 DE485/TIN DI/TIN Z(B) Y(A) X X X /8-unit load /8-unit load X X X /8-unit load /8-unit load X X X /8-unit load /8-unit load Table 9. MAX36E DE485 DI Z Y X X High-impedance High-impedance X X High-impedance High-impedance RS-485/RS-4 Receivers Truth Tables Table. MAX36E OUTPUT RS-485/RS-3 HDPLX (A - B)* (Y - Z)* RO/ROUT X X X High-impedance up to -5mV X -mv X Floating X X -5mV X -mv X Floating X X X X RS-3 mode *Y and Z correspond to pins Y(A)/TOUT and Z(B)/TOUT. A and B correspond to pins A/RIN and B/RIN.

23 Table. MAX36E SUPPLY VOLTAGE (V) C (µf) OUTPUT RS-485/RS-3 HDPLX A - B Y(A) - Z(B) RO/ROUT X X X High-impedance up to -5mV X -mv X Floating X X -5mV X -mv X Floating X X X X RS-3 mode Table. MAX36E OUTPUT RE485 A - B RO X X High-impedance X X High-impedance -5mV -mv Inputs RS-485/RS-4 Receivers Truth Tables (continued) Table 3. Required Minimum Capacitance Values C, C3, C4, C BYPASS (µf) +3. to to to

24 Table 4. Cable Connections Commonly Used for EIA/TIA-3 and V.4 Asynchronous Interfaces EIA/TIA-3 STANDARD CONNECTOR PIN MAX36E MAX36E MAX36E PIN NUMBER FUNCTION (AS SEEN BY DTE) EQUIVALENT MAX36E MAX36E MAX36E DCD Data carrier detect RD RIN Received data TD 3 TOUT Transmitted data DTR 4 Data terminal ready SG 5 GND Signal ground DSR 6 Data set ready RTS 7 TOUT Req uest to send ( = D TE ready) CTS 8 RIN 4 8 Clear to send (= DCE ready) RI 9 Ring indicator MAX3 UART SPI TX RX RTS CTS V 4 HDPLX DI/TIN TOUT 5 RO/ROUT RIN 7 DE485/TIN TOUT 9 MAX36E 8 ROUT RIN 9 8 Y(A) 7 RS-485/ Z(B) 6 GND FAST RS Typical Application Circuit RS-485 RS-3 DB9 RJ45 µp RS-485/RS-3 MULTIPROTOCOL BUS MULTIPLEXER 4

25 TOP VIEW C+ V+ 9 C+ 8 C- 7 V- 6 DI/TIN 5 DE485/TIN 4 B/RIN 3 A/RIN C- GND Z(B)/TOUT Y(A)/TOUT ROUT RO/ROUT PART FAST MAX36E SSOP DUAL MODE HDPLX RS-485/RS-3 MAX36E 4 3 V+ C+ C- V- DI/TIN C+ C- GND TOUT V+ C+ C- V- TIN DE485/TIN RIN RIN Z Y TOUT MAX36E 3 DI DE485 TIN 6 B ROUT 9 RIN 5 A ROUT 9 RIN 4 HDPLX RO 8 B 3 RS-485/RS-3 RE485 7 A SSOP 3 6 TE3 FAST 4 5 RE3 SSOP FLOW- THROUGH PINOUT C+ GND TOUT Z(B) Y(A) TOUT ROUT 9 RO/ROUT FAST Selector Guide RS-485 INPUT UNIT LOADS MAX36E No Yes /4 MAX36E No No /8 MAX36E Yes Yes /8 C- TRANSISTOR COUNT: 85 PROCESS: CMOS Pin Configurations Chip Information 5

26 e D B N E A A DIM A A B C D E e H L INCHES MILLIMETERS MIN MAX MIN MAX SEE VARIATIONS BSC.65 BSC NOTES:. D&E DO NOT INCLUDE MOLD FLASH.. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED.5 MM (.6"). 3. CONTROLLING DIMENSION: MILLIMETERS. 4. MEETS JEDEC MO5. 5. LEADS TO BE COPLANAR WITHIN. MM. H L D D D D D Package Information PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, SSOP, 5.3 MM APPROVAL INCHES MIN MAX DOCUMENT CONTROL NO. MILLIMETERS MIN MAX C REV. -56 C N 4L 6L L 4L 8L SSOP.EPS Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 6 Maxim Integrated Products, San Gabriel Drive, Sunnyvale, CA Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.