±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers

Transcription

1 9-4; ev 3; 7/96 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers General escription The MX48E, MX483E, MX485E, MX487E MX49E, Features ES Protection: ±5kV Human ody Model and MX487E are low-power traceivers for S-485 and Slew-ate Limited for Error-Free ata S-422 communicatio in harsh environments. Each driver output and receiver input is protected agait ±5kV electrostatic Tramission (MX483E/487E/488E/489E) discharge (ES) shocks, without latchup. These parts Low Quiescent Current: contain one driver and one receiver. The MX483E, MX487E, MX488E, and MX489E feature reduced slewrate drivers that minimize EMI and reduce reflectio caused 23µ (MX487E) 2µ (MX483E/487E/488E/489E) by improperly terminated cables, thus allowing error-free 3µ (MX48E/485E/49E/49E) data tramission up to 25kbps. The driver slew rates of the -7V to +2V Common-Mode Input Voltage ange MX48E, MX485E, MX49E, MX49E, and MX487E are not limited, allowing them to tramit up to 2.5Mbps. Three-State Outputs These traceivers draw as little as 2µ supply current 3 Propagation elays, 5 Skew when unloaded or when fully loaded with disabled drivers (MX48E/485E/49E/49E/487E) (see Selection Table). dditionally, the MX48E, MX483E, and MX487E have a low-current shutdown Full-uplex and Half-uplex Versio vailable mode in which they coume only.5µ. ll parts operate llows up to 28 Traceivers on the us from a single +5V supply. (MX487E/MX487E) rivers are short-circuit current limited, and are protected agait excessive power dissipation by thermal shutdown Current Limiting and Thermal Shutdown for circuitry that places their outputs into a high-impedance river Overload Protection state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit. The MX487E and MX487E feature quarter-unit-load receiver input impedance, allowing up to 28 traceivers on the bus. The MX488E MX49E are designed for fullduplex communicatio, while the MX48E, MX483E, Ordering Information MX485E, MX487E, and MX487E are designed for halfduplex applicatio. For applicatio that are not ES sen- PT TEMP. NGE PIN-PCKGE sitive see the pin- and function-compatible MX48, MX48ECP C to +7 C 8 Plastic IP MX483, MX485, MX487 MX49, and MX487. pplicatio Low-Power S-485 Traceivers MX48ECS MX48EEP MX48EES C to +7 C -4 C to +85 C -4 C to +85 C 8 Plastic IP Low-Power S-422 Traceivers Ordering Information continued on last page. Level Tralators Traceivers for EMI-Seitive pplicatio Industrial-Control Local rea Networks Selection Table PT NUME MX48E MX483E MX485E MX487E MX488E MX489E MX49E MX49E MX487E HLF/FULL UPLEX Half Half Half Half Full Full Full Full Half T TE (Mbps) SLEW-TE LIMITE LOW-POWE SHUTOWN ECEIVE/ IVE ENLE QUIESCENT CUENT (µ) NUME OF TNSMITTES ON US PIN COUNT MX48E/MX483E/MX485E/MX487E MX49E/MX487E Maxim Integrated Products For free samples & the latest literature: or phone

2 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E SOLUTE MXIMUM TINGS Supply Voltage (V CC)...2V Control Input Voltage ( E, E)...-.5V to (V CC +.5V) river Input Voltage (I)...-.5V to (V CC +.5V) river Output Voltage (, ;, )...-8V to +2.5V eceiver Input Voltage (, )...-8V to +2.5V eceiver Output Voltage (O)...-.5V to (V CC +.5V) Continuous Power issipation (T = +7 C) 8-Pin Plastic IP (derate 9.9mW/ C above +7 C)...727mW C ELECTICL CHCTEISTICS (V CC = 5V ±5%, T = T MIN to T MX, unless otherwise noted.) (tes, 2) 4-Pin Plastic IP (derate.mw/ C above +7 C)..8mW 8-Pin SO (derate 5.88mW/ C above +7 C)...47mW 4-Pin SO (derate 8.33mW/ C above +7 C)...667mW Operating Temperature anges MX4 C /MX487EC_... C to +7 C MX4 E /MX487EE_...-4 C to +85 C Storage Temperature ange C to +6 C Lead Temperature (soldering, sec)...+3 C Stresses beyond those listed under bsolute Maximum atings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditio beyond those indicated in the operational sectio of the specificatio is not implied. Exposure to absolute maximum rating conditio for extended periods may affect device reliability. PMETE SMOL CONITIONS MIN TP MX UNITS ifferential river Output (no load) V O 5 V ifferential river Output = 5Ω (S-422) 2 V O2 (with load) = 27Ω (S-485), Figure V Change in Magnitude of river ifferential Output Voltage for Complementary Output States V O = 27Ω or 5Ω, Figure 8.2 V river Common-Mode Output Voltage V OC = 27Ω or 5Ω, Figure 8 3 V Change in Magnitude of river Common-Mode Output Voltage for Complementary Output States V O = 27Ω or 5Ω, Figure 8.2 V Input High Voltage V IH E, I, E 2. V Input Low Voltage V IL E, I, E.8 V Input Current I IN E, I, E ±2 µ Input Current (, ) eceiver ifferential Threshold V V Voltage TH -7V V CM 2V eceiver Input Hysteresis V TH V CM = V 7 mv eceiver Output High Voltage V OH I O = -4m, V I = 2mV 3.5 eceiver Output Low Voltage V OL I O = 4m, V I = -2mV.4 Three-State (high impedance) Output Current at eceiver I IN2 E = V; V CC = V or 5.25V, all devices except MX487E/MX487E MX487E/MX487E, E = V, V CC = V or 5.25V V IN = 2V V IN = -7V V IN = 2V V IN = -7V I O.4V V O 2.4V ± µ -7V V CM 2V, all devices except MX487E/MX487E 2 kω eceiver Input esistance IN -7V V CM 2V, MX487E/MX487E 48 kω m m V V 2

3 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers C ELECTICL CHCTEISTICS (continued) (V CC = 5V ±5%, T = T MIN to T MX, unless otherwise noted.) (tes, 2) PMETE -Load Supply Current (te 3) Supply Current in Shutdown river Short-Circuit Current, V O = High river Short-Circuit Current, V O = Low eceiver Short-Circuit Current ES Protection SMOL I CC I SHN I OS I OS2 I OS CONITIONS MX483E MX483E/MX487E, E = V CC MX487E 25 4 E = V or V CC E = V 2 25 MX48E/483E/487E, E = V, E = V CC.5-7V V O 2V (te 4) -7V V O 2V (te 4) V V O V CC,, and pi, tested using Human ody Model MIN TP MX MX488E/MX489E, E, I, E = V or V CC 2 25 MX49E/MX49E, E, I, E = V or V CC 3 5 MX48E/MX485E, E E = V CC 5 9 = V or V CC E = V 3 5 MX487E, E E = V CC 3 5 = V or V CC E = V ±5 SWITCHING CHCTEISTICS MX48E/MX485E, MX49E/MX49E, MX487E (V CC = 5V ±5%, T = T MIN to T MX, unless otherwise noted.) (tes, 2) Figures and 2, MX48E, MX485E, MX487E river ise or Fall Time t, t F IFF = 54Ω, C L = C L2 = pf MX49EC/E, MX49EC/E UNITS PMETE SMOL CONITIONS MIN TP MX UNITS t PLH Figures and 2, 4 6 river Input to Output IFF = 54Ω, t PHL C L = C L2 = pf 4 6 river Output Skew to Output t SKEW Figures and 2, IFF = 54Ω, C L = C L2 = pf 5 river Enable to Output High t H Figures and 3, C L = pf, S2 closed 45 7 river Enable to Output Low t L Figures and 3, C L = pf, S closed 45 7 river isable Time from Low t L Figures and 3, C L = 5pF, S closed 45 7 river isable Time from High t H Figures and 3, C L = 5pF, S2 closed 45 7 Figures and 4, MX48E, MX485E, MX487E eceiver Input to Output t PLH, t PHL IFF = 54Ω, C L = C L2 = pf MX49EC/E, MX49EC/E t PLH - t PHL ifferential Figures and 4, t IFF = 54Ω, SK eceiver Skew C L = C L2 = pf 5 eceiver Enable to Output Low t L Figures 9 and 5, C L = 5pF, S closed 2 5 eceiver Enable to Output High t H Figures 9 and 5, C L = 5pF, S2 closed 2 5 eceiver isable Time from Low t L Figures 9 and 5, C L = 5pF, S closed 2 5 eceiver isable Time from High t H Figures 9 and 5, C L = 5pF, S2 closed 2 5 Maximum ata ate f MX 2.5 Mbps Time to Shutdown t SHN MX48E (te 5) µ µ m m m kv MX48E/MX483E/MX485E/MX487E MX49E/MX487E 3

4 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E SWITCHING CHCTEISTICS MX48E/MX485E, MX49E/MX49E, MX487E (continued) (V CC = 5V ±5%, T = T MIN to T MX, unless otherwise noted.) (tes, 2) PMETE river Enable from Shutdown to Output High (MX48E) river Enable from Shutdown to Output Low (MX48E) eceiver Enable from Shutdown to Output High (MX48E) eceiver Enable from Shutdown to Output Low (MX48E) SMOL t H(SHN) t L(SHN) t H(SHN) t L(SHN) CONITIONS Figures and 3, C L = pf, S2 closed Figures and 3, C L = pf, S closed Figures 9 and 5, C L = 5pF, S2 closed, - = 2V Figures 9 and 5, C L = 5pF, S closed, - = 2V MIN TP MX SWITCHING CHCTEISTICS MX483E, MX487E/MX488E/MX489E (V CC = 5V ±5%, T = T MIN to T MX, unless otherwise noted.) (tes, 2) PMETE river Input to Output river Output Skew to Output river ise or Fall Time river Enable to Output High river Enable to Output Low river isable Time from Low river isable Time from High eceiver Input to Output I t PLH - t PHL I ifferential eceiver Skew eceiver Enable to Output Low eceiver Enable to Output High eceiver isable Time from Low eceiver isable Time from High Maximum ata ate Time to Shutdown river Enable from Shutdown to Output High river Enable from Shutdown to Output Low eceiver Enable from Shutdown to Output High eceiver Enable from Shutdown to Output Low SMOL CONITIONS t PLH Figures and 2, IFF = 54Ω, t PHL C L = C L2 = pf t SKEW Figures and 2, IFF = 54Ω, C L = C L2 = pf t, t F t H t L t L t H t PLH t PHL t SK t L t H t L t H f MX t SHN t H(SHN) t L(SHN) t H(SHN) t L(SHN) Figures and 2, IFF = 54Ω, C L = C L2 = pf Figures and 3, C L = pf, S2 closed Figures and 3, C L = pf, S closed Figures and 3, C L = 5pF, S closed Figures and 3, C L = 5pF, S2 closed Figures and 4, IFF = 54Ω, C L = C L2 = pf Figures and 4, IFF = 54Ω, C L = C L2 = pf Figures 9 and 5, C L = 5pF, S closed Figures 9 and 5, C L = 5pF, S2 closed Figures 9 and 5, C L = 5pF, S closed Figures 9 and 5, C L = 5pF, S2 closed t PLH, t PHL < 5% of data period MX483E/MX487E (te 5) MX483E/MX487E, Figures and 3, C L = pf, S2 closed MX483E/MX487E, Figures and 3, C L = pf, S closed MX483E/MX487E, Figures 9 and 5, C L = 5pF, S2 closed MX483E/MX487E, Figures 9 and 5, C L = 5pF, S closed MIN TP MX UNITS UNITS kbps 4

5 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers NOTES FO ELECTICL/SWITCHING CHCTEISTICS te : ll currents into device pi are positive; all currents out of device pi are negative. ll voltages are referenced to device ground unless otherwise specified. te 2: ll typical specificatio are given for V CC = 5V and T = +25 C. te 3: Supply current specification is valid for loaded tramitters when E = V. te 4: pplies to peak current. See Typical Operating Characteristics. te 5: The MX48E/MX483E/MX487E are put into shutdown by bringing E high and E low. If the inputs are in this state for less than 5, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 6, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section. Typical Operating Characteristics (V CC = 5V, T = +25 C, unless otherwise noted.) OUTPUT CUENT (m) OUTPUT CUENT vs. ECEIVE OUTPUT LOW VOLTGE OUTPUT LOW VOLTGE (V) OUTPUT LOW VOLTGE (V) ECEIVE OUTPUT LOW VOLTGE vs. TEMPETUE TEMPETUE ( C) MX48E- OUTPUT CUENT (m) OUTPUT HIGH VOLTGE (V) I O = 8m OUTPUT CUENT vs. ECEIVE OUTPUT HIGH VOLTGE MX48E-4 OUTPUT CUENT (m) MX48E-2 5. OUTPUT HIGH VOLTGE (V) ECEIVE OUTPUT HIGH VOLTGE vs. TEMPETUE I O = 8m TEMPETUE ( C) IVE OUTPUT CUENT vs. IFFEENTIL OUTPUT VOLTGE IFFEENTIL OUTPUT VOLTGE (V) MX48E-5 MX48E-3 MX48E/MX483E/MX485E/MX487E MX49E/MX487E 5

6 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E Typical Operating Characteristics (continued) (V CC = 5V, T = +25 C, unless otherwise noted.) IFFEENTIL OUTPUT VOLTGE (V) SUPPL CUENT (µ) IVE IFFEENTIL OUTPUT VOLTGE vs. TEMPETUE = 54Ω TEMPETUE ( C) MX48E/MX485E/MX49E/MX49E SUPPL CUENT vs. TEMPETUE MX48E/MX485E; E = VCC, E = X MX485E; E =, E = X, MX48E; E = E = MX49E/MX49E; E = E = X MX48E-6 MX48E-9 OUTPUT CUENT (m) SUPPL CUENT (µ) OUTPUT CUENT vs. IVE OUTPUT LOW VOLTGE OUTPUT LOW VOLTGE (V) MX48E; E =, E = V CC MX483E/MX487E; E =, E = VCC TEMPETUE ( C) TEMPETUE ( C) MX483E/MX487E MX489E SUPPL CUENT vs. TEMPETUE MX483E; E = V CC, E = X MX487E; E = VCC, E = X MX483E/MX487E; E = E =, MX488E/MX489E; E = E = X MX48E-7 MX48E- OUTPUT CUENT (m) SUPPL CUENT (µ) OUTPUT CUENT vs. IVE OUTPUT HIGH VOLTGE OUTPUT HIGH VOLTGE (V) MX487E SUPPL CUENT vs. TEMPETUE MX487E; E = VCC, E = X MX487E; E = V, E = X TEMPETUE ( C) MX48E-8 MX48E- 6

7 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers Pin escription MX48E/MX483E MX485E/MX487E MX487E PIN MX488E MX49E eceiver Output: If > by 2mV, O will be high; If < by 2mV, O will be low. eceiver Output Enable. O is enabled when E is low; O is high impedance when E is high. river Output Enable. The driver outputs, and, are enabled by bringing E high. They are high impedance when E is low. If the driver outputs are enabled, the parts function as line drivers. While they are high impedance, they function as line receivers if E is low I river Input. low on I forces output low and output high. Similarly, a high on I forces output high and output low , 7 GN Ground 5 9 ninverting river Output 6 Inverting river Output 6 MX489E MX49E NME O E E FUNCTION ninverting eceiver Input and ninverting river Output 8 2 ninverting eceiver Input 7 Inverting eceiver Input and Inverting river Output 7 Inverting eceiver Input 8 4 V CC Positive Supply: 4.75V V CC 5.25V, 8, 3 N.C. Connect not internally connected MX48E/MX483E/MX485E/MX487E MX49E/MX487E 7

8 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E TOP VIEW TOP VIEW TOP VIEW O E 2 E 3 I 4 V CC O 2 I 3 GN 4 N.C. O E E I GN GN IP/SO IP/SO IP/SO 8 V CC GN V CC 3 N.C N.C. I O O E 2 E 3 I 4 I O , 8, 3 NC V CC E 4 GN 4 E 5 6.µF 8 t 7 Figure 2. MX488E/MX49E Pin Configuration and Typical Operating Circuit MX488E MX49E NOTE: TPICL OPETING CICUIT SHOWN WITH IP/SO PCKGE. V CC , 7 GN 8 V CC 7 t 6 5 GN.µF 2 t Figure 3. MX489E/MX49E Pin Configuration and Typical Operating Circuit.µF MX48E MX483E MX485E MX487E MX487E NOTE: PIN LELS N ON TIMING, TEST, N WVEFOM IGMS EFE TO PINS N WHEN E IS HIGH. TPICL OPETING CICUIT SHOWN WITH IP/SO PCKGE. Figure. MX48E/MX483E/MX485E/MX487E/MX487E Pin Configuration and Typical Operating Circuit MX489E MX49E t t t V CC E GN E E V CC GN E I O O I O I 8

9 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers Function Tables (MX48E/MX483E/MX485E/MX487E/MX487E) Table. Tramitting Table 2. eceiving INPUTS OUTPUTS E E I X X X X High- High-* High- High-* X = on't care High- = High impedance * Shutdown mode for MX48E/MX483E/MX487E pplicatio Information The MX48E/MX483E/MX485E/MX487E MX49E and MX487E are low-power traceivers for S-485 and S-422 communicatio. These E versio of the MX48, MX483, MX485, MX487 MX49, and MX487 provide extra protection agait ES. The rugged MX48E, MX483E, MX485E, MX497E MX49E, and MX487E are intended for harsh environments where high-speed communication is important. These devices eliminate the need for traient suppressor diodes and the associated high capacitance loading. The standard (non- E ) MX48, MX483, MX485, MX487 MX49, and MX487 are recommended for applicatio where cost is critical. The MX48E, MX485E, MX49E, MX49E, and MX487E can tramit and receive at data rates up to 2.5Mbps, while the MX483E, MX487E, MX488E, and MX489E are specified for data rates up to 25kbps. The MX488E MX49E are full-duplex traceivers, while the MX48E, MX483E, MX487E, and MX487E are half-duplex. In addition, driverenable (E) and receiver-enable (E) pi are included on the MX48E, MX483E, MX485E, MX487E, MX489E, MX49E, and MX487E. When disabled, the driver and receiver outputs are high impedance. INPUTS OUTPUT E E - O > +.2V < -.2V Inputs open X High-* X = on't care High- = High impedance * Shutdown mode for MX48E/MX483E/MX487E ±5kV ES Protection s with all Maxim devices, ES-protection structures are incorporated on all pi to protect agait electrostatic discharges encountered during handling and assembly. The driver outputs and receiver inputs have extra protection agait static electricity. Maxim s engineers developed state-of-the-art structures to protect these pi agait ES of ±5kV without damage. The ES structures withstand high ES in all states: normal operation, shutdown, and powered down. fter an ES event, Maxim s MX48E, MX483E, MX485E, MX487E MX49E, and MX487E keep working without latchup. ES protection can be tested in various ways; the tramitter outputs and receiver inputs of this product family are characterized for protection to ±5kV using the Human ody Model. Other ES test methodologies include IEC4-2 contact discharge and IEC-4-2 air-gap discharge (formerly IEC8-2). ES Test Conditio ES performance depends on a variety of conditio. Contact Maxim for a reliability report that documents test set-up, test methodology, and test results. Human ody Model Figure 4 shows the Human ody Model, and Figure 5 shows the current waveform it generates when discharged into a low impedance. This model coists of a pf capacitor charged to the ES voltage of interest, which is then discharged into the test device through a.5kω resistor. IEC-4-2 The IEC-4-2 standard covers ES testing and performance of finished equipment; it does not specifically refer to integrated circuits (Figure 6). MX48E/MX483E/MX485E/MX487E MX49E/MX487E 9

10 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E HIGH VOLTGE C SOUCE HIGH- VOLTGE C SOUCE C 5M to M CHGE CUENT LIMIT ESISTO Cs 5pF 33Ω ISCHGE ESISTNCE STOGE CPCITO Figure 6. IEC-4-2 ES Test Model C M CHGE CUENT LIMIT ESISTO Cs pf V O Figure 8. river C Test Load 5Ω ISCHGE ESISTNCE STOGE CPCITO Figure 4. Human ody ES Test Model V OC EVICE UNE TEST EVICE UNE TEST MPEES IPEK I P % 9% 36.8% % % 9% % tr =.7 to I t L 3 6 Figure 7. IEC-4-2 ES Generator Current Waveform TEST POINT ECEIVE OUTPUT C L 5pF Figure 9. eceiver Timing Test Load TIME t L CUENT WVEFOM Figure 5. Human ody Model Current Waveform k Ir S S2 PEK-TO-PEK INGING (NOT WN TO SCLE) k V CC t

11 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers I 3V E V I C L IFF C L2 Figure. river/eceiver Timing Test Circuit 3V I V V O V IFF V -V O V O.5V /2 V O % t t PLH V IFF = V () - V () 9% 9% t F t SKEW = t PLH - t PHL Figure 2. river Propagation elays V OH O V OL V - I -V I V.5V t PHL INPUT E t PHL.5V OUTPUT Figure 4. eceiver Propagation elays t PLH.5V V O /2 V O % OUTPUT UNE TEST C L 5Ω Figure. river Timing Test Load 3V E V, V OL, V.5V.5V S S2 2.3V OUTPUT NOMLL LOW 2.3V t L(SHN), t L t L OUTPUT NOMLL HIGH t H(SHN), t H t H V CC V OL +.5V V OH -.5V Figure 3. river Enable and isable Times (except MX488E and MX49E) 3V E V V CC O O V.5V.5V.5V OUTPUT NOMLL LOW.5V t L(SHN), t L OUTPUT NOMLL HIGH t H(SHN), t H t L t H V OL +.5V V OH -.5V Figure 5. eceiver Enable and isable Times (except MX488E and MX49E) MX48E/MX483E/MX485E/MX487E MX49E/MX487E

12 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E d/div Hz 5kHz/div 5MHz Figure 6. river Output Waveform and FFT Plot of MX485E/MX49E/MX49E/MX487E Tramitting a 5kHz Signal The major difference between tests done using the Human ody Model and IEC-4-2 is higher peak current in IEC-4-2, because series resistance is lower in the IEC-4-2 model. Hence, the ES withstand voltage measured to IEC-4-2 is generally lower than that measured using the Human ody Model. Figure 7 shows the current waveform for the 8kV IEC-4-2 ES contact-discharge test. The air-gap test involves approaching the device with a charged probe. The contact-discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ES tests all pi using a 2pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing. Of course, all pi require this protection during manufacturing not just inputs and outputs. Therefore, after PC board assembly, the Machine Model is less relevant to I/O ports. MX487E/MX487E: 28 Traceivers on the us The 48kΩ, /4-unit-load receiver input impedance of the MX487E and MX487E allows up to 28 traceivers on a bus, compared to the -unit load (2kΩ input impedance) of standard S-485 drivers (32 traceivers maximum). ny combination of MX487E/MX487E and other S-485 traceivers with a total of 32 unit loads or less can be put on the bus. The MX48E, MX483E, MX485E, and MX488E MX49E have standard 2kΩ receiver input impedance. d/div Hz 5kHz/div 5MHz Figure 7. river Output Waveform and FFT Plot of MX483E/MX487E MX489E Tramitting a 5kHz Signal MX483E/MX487E/MX488E/MX489E: educed EMI and eflectio The MX483E and MX487E MX489E are slew-rate limited, minimizing EMI and reducing reflectio caused by improperly terminated cables. Figure 6 shows the driver output waveform and its Fourier analysis of a 5kHz signal tramitted by a MX48E, MX485E, MX49E, MX49E, or MX487E. Highfrequency harmonics with large amplitudes are evident. Figure 7 shows the same information displayed for a MX483E, MX487E, MX488E, or MX489E tramitting under the same conditio. Figure 7 s high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced. Low-Power Shutdown Mode (MX48E/MX483E/MX487E) low-power shutdown mode is initiated by bringing both E high and E low. The devices will not shut down unless both the driver and receiver are disabled. In shutdown, the devices typically draw only.5µ of supply current. E and E may be driven simultaneously; the parts are guaranteed not to enter shutdown if E is high and E is low for less than 5. If the inputs are in this state for at least 6, the parts are guaranteed to enter shutdown. For the MX48E, MX483E, and MX487E, the t H and t L enable times assume the part was not in the low-power shutdown state (the MX485E, MX488E MX49E, and MX487E can not be shut down). The t H(SHN) and tl(shn) enable times assume the parts were shut down (see Electrical Characteristics). 2

13 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers TTL IN t, t F < 6 pf pf = 54Ω Figure 8. eceiver Propagation elay Test Circuit It takes the drivers and receivers longer to become enabled from the low-power shutdown state (th(shn), tl(shn)) than from the operating mode (th, tl). (The parts are in operating mode if the E, E inputs equal a logical, or, or,.) river Output Protection Excessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. foldback current limit on the output stage provides immediate protection agait short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). In addition, a thermal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively. Propagation elay Many digital encoding schemes depend on the difference between the driver and receiver propagation ECEIVE OUT delay times. Typical propagation delays are shown in Figures 9 22 using Figure 8 s test circuit. The difference in receiver delay times, tplh - tphl, is typically under 3 for the MX48E, MX485E, MX49E, MX49E, and MX487E, and is typically less than for the MX483E and MX487E MX489E. The driver skew times are typically 5 ( max) for the MX48E, MX485E, MX49E, MX49E, and MX487E, and are typically (8 max) for the MX483E and MX487E MX489E. Typical pplicatio The MX48E, MX483E, MX485E, MX487E MX49E, and MX487E traceivers are designed for bidirectional data communicatio on multipoint bus tramission lines. Figures 25 and 26 show typical network application circuits. These parts can also be used as line repeaters, with cable lengths longer than 4 feet. To minimize reflectio, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possible. The slew-rate-limited MX483E and MX487E MX489E are more tolerant of imperfect termination. ypass the VCC pin with.µf. Isolated S-485 For isolated S-485 applicatio, see the MX253 and MX48 data sheets. Line Length vs. ata ate The S-485/S-422 standard covers line lengths up to 4 feet. Figures 23 and 24 show the system differential voltage for the parts driving 4 feet of 26WG twisted-pair wire at khz into Ω loads. MX48E/MX483E/MX485E/MX487E MX49E/MX487E 3

14 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E 5mV/div O 5V/div 25/div Figure 9. MX48E/MX485E/MX49E/MX487E eceiver t PHL 5mV/div O 5V/div 2/div Figure 2. MX483E/MX487E MX489E eceiver t PHL I V - V O 2µs/div Figure 23. MX48E/MX485E/MX49E/MX49E/ MX487E System ifferential Voltage at khz riving 4ft of Cable 5V V -V 5V V 5mV/div 5V/div O 25/div Figure 2. MX48E/MX485E/MX49E/MX49E/ MX487E eceiver t PLH 5mV/div 5V/div O 2/div Figure 22. MX483E/MX487E MX489E eceiver t PLH I V - V O 2µs/div Figure 24. MX483E/MX487E MX489E System ifferential Voltage at khz riving 4ft of Cable 5V V V -V 5V V 4

15 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers I E O E O E E I MX48E MX483E MX485E MX487E MX487E 2Ω 2Ω E E O Figure 26. MX488E MX49E Full-uplex S-485 Network 2Ω NOTE: E N E ON MX489E/MX49E ONL. I I E O E I E I O E Figure 25. MX48E/MX483E/MX485E/MX487E/MX487E Typical Half-uplex S-485 Network 2Ω E E O 2Ω 2Ω MX488E MX489E MX49E MX49E E I O E I E E O MX48E/MX483E/MX485E/MX487E MX49E/MX487E 5

16 ±5kV ES-Protected, Slew-ate-Limited, Low-Power, S-485/S-422 Traceivers MX48E/MX483E/MX485E/MX487E MX49E/MX487E Ordering Information (continued) PT MX483ECP MX483ECS MX483EEP MX483EES MX485ECP MX485ECS MX485EEP MX485EES MX487ECP MX487ECS MX487EEP MX487EES MX488ECP MX488ECS MX488EEP MX488EES TEMP. NGE C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C PIN-PCKGE 8 Plastic IP 8 Plastic IP 8 Plastic IP 8 Plastic IP 8 Plastic IP 8 Plastic IP 8 Plastic IP 8 Plastic IP Chip Information TNSISTO COUNT: 295 PT MX489ECP MX489ECS MX489EEP MX489EES MX49ECP MX49ECS MX49EEP MX49EES MX49ECP MX49ECS MX49EEP MX49EES MX487ECP MX487ECS MX487EEP MX487EES TEMP. NGE C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C PIN-PCKGE 4 Plastic IP 4 SO 4 Plastic IP 4 SO 8 Plastic IP 8 Plastic IP 4 Plastic IP 4 SO 4 Plastic IP 4 SO 8 Plastic IP 8 Plastic IP Maxim cannot assume respoibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. circuit patent licees are implied. Maxim reserves the right to change the circuitry and specificatio without notice at any time. 6 Maxim Integrated Products, 2 San Gabriel rive, Sunnyvale, C 9486 (48) Maxim Integrated Products Printed US is a registered trademark of Maxim Integrated Products.