19-2536; Rev 0; 7/02 ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT Features ♦ True Fail-Safe Receiver While Maintaining EIA/TIA-485 Compatibility The MAX3060E features slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 115kbps. The MAX3061E, also slewrate limited, transmits up to 500kbps. The MAX3062E driver is not slew-rate limited, allowing transmit speeds up to 20Mbps. All transmitter outputs are protected to ±15kV using the Human Body Model. ♦ ESD Protection: ±15kV Human Body Model These transceivers typically draw 910µA of supply current when unloaded, or 790µA when fully loaded with the drivers disabled. All devices have a 1/8-unit-load receiver input impedance that allows up to 256 transceivers on the bus. These devices are intended for half-duplex communication. ♦ Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission (MAX3060E and MAX3061E) ♦ 1nA Low-Current Shutdown Mode ♦ Hot-Swappable for Telecom Applications ♦ Allow Up to 256 Transceivers on the Bus ♦ Space-Saving 8-Pin SOT23 Package Ordering Information PART TEMP RANGE PINPACKAGE TOP MARK MAX3060EEKA-T -40°C to +85°C 8 SOT23-8 AAKI MAX3061EEKA-T -40°C to +85°C 8 SOT23-8 AAKJ MAX3062EEKA-T -40°C to +85°C 8 SOT23-8 AAKK Selector Guide Applications RS-422/RS-485 Communications Level Translators Transceivers for EMI-Sensitive Applications Industrial-Control Local-Area Networks PART DATA RATE (Mbps) SLEWRATE LIMITED TRANSCEIVERS ON BUS MAX3060E 0.115 Yes 256 MAX3061E 0.5 Yes 256 MAX3062E 20 No 256 Typical Operating Circuit/Pin Configuration +5V 0.1µF TOP VIEW RO 1 R RE 2 DE 3 DI 4 D 8 VCC 7 B Rt 6 A 5 GND MAX3060E MAX3061E MAX3062E DE D DI B Rt A RO R RE ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3060E/MAX3061E/MAX3062E General Description The MAX3060E/MAX3061E/MAX3062E high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature failsafe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This means that the receiver output is a logic high if all transmitters on a terminated bus are disabled (high impedance). These devices also feature hot-swap circuitry that eliminates data glitches during hot insertion. MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT ABSOLUTE MAXIMUM RATINGS All Voltages with Respect to GND Supply Voltage (VCC) ............................................................+7V Input Voltage (RE, DE, DI)..........................-0.3V to (VCC + 0.3V) Driver Output/Receiver Input Voltage (A, B) .......-7.5V to +12.5V Receiver Output Voltage (RO)....................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) 8-Pin SOT23 (derate 8.9mW/°C above +70°C)............714mW Operating Temperature Range MAX306_EE_ _ ................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Junction Temperature ......................................................+150°C Lead Temperature (soldering, 10s) .................................+300°C 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. DC ELECTRICAL CHARACTERISTICS (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5 V DRIVER Differential Driver Output (No Load) VOD1 Differential Driver Output VOD2 Change in Magnitude of Differential Output Voltage ∆VOD Figure 1, R = 50Ω or R = 27Ω (Note 3) Driver Common-Mode Output Voltage VOC Figure 1, R = 50Ω or R = 27Ω Change in Magnitude of Common-Mode Voltage ∆VOC Figure 1, R = 50Ω or R = 27Ω (Note 3) VCC = 5V Figure 1, R = 50Ω (RS-422) 2.0 Figure 1, R = 27Ω (RS-485) 1.5 VIH DE, DI, RE Input Low Voltage VIL DE, DI, RE DI Input Hysteresis VHYS Input High Voltage Input Current Hot-Swap Driver Input Current Input Current (A and B) Driver Short-Circuit Output Current IIN1 IHOTSWAP IIN2 VOD1 2 0.2 V 3 V 0.2 V 2.0 V 0.8 100 DE, DI, RE DE, RE (Note 4) DE = GND, VCC = GND or 5.25V VIN = +12V VIN = -7V -7V ≤ VOUT ≤ +12V, TA = +25°C (Note 5) IEC 1000-4-2 Air-Gap Discharge ESD Protection for A, B V ±1 µA ±200 µA 125 -100 ±15 V mV ±250 µA mA ±7 IEC 1000-4-2 Contact Discharge ±7 Human Body Model ±15 _______________________________________________________________________________________ kV ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS -200 -125 -50 mV RECEIVER Receiver Differential Threshold Voltage VTH Receiver Input Hysteresis ∆VTH Receiver Output High Voltage VOH IO = -4mA, VID = -50mV Receiver Output Low Voltage VOL IO = 4mA, VID = -200mV Three-State Output Current at Receiver IOZR 0V ≤ VO ≤ VCC Receiver Input Resistance RIN -7V ≤ VCM ≤ +12V 96 Receiver Output Short-Circuit Current IOSR 0V ≤ VRO ≤ VCC ±8 ICC No load, DI = GND or VCC -7V ≤ VCM ≤ +12V 25 mV VCC - 1.5 V 0.01 0.4 V ±1 µA kΩ ±80 mA SUPPLY CURRENT Supply Current Supply Current in Shutdown Mode ISHDN DE = GND, RE = VCC DE = RE = GND 790 1400 DE = RE = VCC 910 1500 0.001 1 µA µA _______________________________________________________________________________________ 3 MAX3060E/MAX3061E/MAX3062E DC ELECTRICAL CHARACTERISTICS (continued) MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT SWITCHING CHARACTERISTICS—MAX3060E (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS tDPLH, tDPHL Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF 1.0 1.7 2.4 µs Driver Output Skew (tDPLH - tDPHL) tDSKEW Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF -200 -7 +200 ns Driver Rise or Fall Time tDR, tDF Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF 1.3 1.85 2.5 µs Driver Input to Output Maximum Data Rate fMAX Driver Enable to Output High tDZH Figures 4 and 6, CL = 100pF, S2 closed 0.6 1.5 µs Driver Enable to Output Low tDZL Figures 4 and 6, CL = 100pF, S1 closed 0.5 1.5 µs Driver Disable Time from Low tDLZ Figures 4 and 6, CL = 15pF, S1 closed 60 200 ns tDHZ Driver Disable Time from High 115 kbps Figures 4 and 6, CL = 15pF, S2 closed 85 200 ns Receiver Input to Output tRPLH, tRPHL Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF 47 80 ns Differential Receiver Skew (tRPLH - tRPHL) tRSKD Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF -3 +10 ns -10 Receiver Enable to Output Low tRZL Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Enable to Output High tRZH Figures 2 and 8, CL = 15pF, S2 closed 50 ns Receiver Disable Time from Low tRLZ Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Disable Time from High tRHZ Figures 2 and 8, CL = 15pF, S2 closed 50 ns 600 ns Time to Shutdown tSHDN (Note 6) 50 180 Driver Enable from Shutdown to Output High tDZH(SHDN) Figures 4 and 6, CL = 100pF, S2 closed 2 µs Driver Enable from Shutdown to Output Low tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed 2 µs Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed 1.5 µs Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed 1.5 µs 4 _______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E SWITCHING CHARACTERISTICS—MAX3061E (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Driver Input to Output tDPLH, tDPHL Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF 250 470 800 ns Driver Output Skew (tDPLH - tDPHL) tDSKEW Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF -100 -4 +100 ns Driver Rise or Fall Time tDR, tDF Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF 200 530 750 ns Maximum Data Rate fMAX Driver Enable to Output High tDZH Figures 4 and 6, CL = 100pF, S2 closed 500 330 1000 ns Driver Enable to Output Low tDZL Figures 4 and 6, CL = 100pF, S1 closed 200 1000 ns Driver Disable Time from Low tDLZ Figures 4 and 6, CL = 15pF, S1 closed 60 200 ns Driver Disable Time from High tDHZ Figures 4 and 6, CL = 15pF, S2 closed 80 200 ns Receiver Input to Output tRPLH, tRPHL Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF 47 80 ns Differential Receiver Skew (tRPLH - tRPHL) tRSKD Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF -3 +10 ns -10 kbps Receiver Enable to Output Low tRZL Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Enable to Output High tRZH Figures 2 and 8, CL = 15pF, S2 closed 50 ns Receiver Disable Time from Low tRLZ Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Disable Time from High tRHZ Figures 2 and 8, CL = 15pF, S2 closed 50 ns 600 ns Time to Shutdown tSHDN (Note 6) 50 180 Driver Enable from Shutdown to Output High tDZH(SHDN Figures 4 and 6, CL = 100pF, S2 closed 1.5 µs Driver Enable from Shutdown to Output Low tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed 1.5 µs Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed 1.5 µs Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed 1.5 µs _______________________________________________________________________________________ 5 MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT SWITCHING CHARACTERISTICS—MAX3062E (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) (Notes 1, 2) PARAMETER SYMBOL CONDITIONS Driver Input to Output tDPLH, tDPHL Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF Driver Output Skew (tDPLH - tDPHL) tDSKEW Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF Driver Rise or Fall Time tDR, tDF Figures 3 and 5, RDIFF = 54Ω, CDIFF = 50pF MIN -10 TYP MAX UNITS 20 30 ns +1 +10 ns 8 15 ns Maximum Data Rate fMAX Driver Enable to Output High tDZH Figures 4 and 6, CL = 100pF, S2 closed 250 500 ns Driver Enable to Output Low tDZL Figures 4 and 6, CL = 100pF, S1 closed 250 500 ns Driver Disable Time from Low tDLZ Figures 4 and 6, CL = 15pF, S1 closed 100 200 ns tDHZ Driver Disable Time from High 20 Mbps Figures 4 and 6, CL = 15pF, S2 closed 100 200 ns Receiver Input to Output tRPLH, tRPHL Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF 45 80 ns Differential Receiver Skew (tRPLH - tRPHL) tRSKD Figures 7 and 9; | VID | ≥ 2.0V; rise and fall time of VID ≤ 4ns, CL = 15pF -4 +10 ns -10 Receiver Enable to Output Low tRZL Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Enable to Output High tRZH Figures 2 and 8, CL = 15pF, S2 closed 50 ns Receiver Disable Time from Low tRLZ Figures 2 and 8, CL = 15pF, S1 closed 50 ns Receiver Disable Time from High tRHZ Figures 2 and 8, CL = 15pF, S2 closed 50 ns 600 ns Time to Shutdown tSHDN (Note 6) 50 180 Driver Enable from Shutdown to Output High tDZH(SHDN) Figures 4 and 6, CL = 100pF, S2 closed 100 ns Driver Enable from Shutdown to Output Low tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed 100 ns Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed 1.5 µs Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed 1.5 µs Note 1: Overtemperature limits are guaranteed by design and are not production tested. Devices are tested at TA = +25°C. Note 2: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device ground, unless otherwise noted. Note 3: ∆VOD and ∆VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 4: This input current level is for the hot-swap enable (DE, RE) inputs and is present until the first transition only. After the first transition, the input reverts to a standard high-impedance CMOS input with input current IIN1. For the first 10µs, the input current can be as high as 1mA. During this period the input is disabled. Note 5: Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during current limiting. Note 6: The device is put into shutdown by bringing RE high and DE low. If the enable inputs are in this state for less than 50ns, the device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteed to have entered shutdown. 6 _______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E A R RECEIVER OUTPUT 1kΩ TEST POINT VCC S1 CL 15pF VOD2 R 1kΩ VOC S2 B Figure 2. Receiver Enable/Disable Timing Test Load Figure 1. Driver DC Test Load 5V DE DI A VOD2 RDIFF VCC S1 500Ω OUTPUT UNDER TEST CDIFF B CL S2 Figure 3. Driver Timing Test Circuit Figure 4. Driver Enable/Disable Timing Test Load 5V DI 1.5V 0 5V 1.5V tDPLH DE tDPHL tDLZ A, B A VO 0 -VO 1.5V tDZL(SHDN), tDZL B VDIFF 1.5V 0 VOL 2.3V OUTPUT NORMALLY LOW VDIFF = V (A) - V (B) 10% tDR 90% 90% tDF tDSKEW = | tDPLH - tDPHL | Figure 5. Driver Propagation Delays OUTPUT NORMALLY HIGH A, B 10% VOL + 0.5V VOH - 0.5V 2.3V 0 tDZH(SHDN), tDZH tDHZ Figure 6. Driver Enable and Disable Times _______________________________________________________________________________________ 7 5V RE 1.5V 1.5V 0 RO VOH A -1V B tRLZ tRZL(SHDN), tRZL 1.5V VOL 1V 1.5V OUTPUT tRPHL VCC RO 1.5V OUTPUT NORMALLY LOW RO 1.5V VOL + 0.5V tRPLH OUTPUT NORMALLY HIGH INPUT VOH - 0.5V 0 tRZH(SHDN), tRZH Figure 7. Receiver Propagation Delays tRHZ Figure 8. Receiver Enable and Disable Times B VID ATE RECEIVER OUTPUT RR A Figure 9. Receiver Propagation Delay Test Circuit Typical Operating Characteristics (VCC = +5V, TA = +25°C, unless otherwise noted.) 850 DE = RE = GND 750 40 30 20 700 10 650 0 18 16 OUTPUT CURRENT (mA) 50 OUTPUT CURRENT (mA) 900 20 MAX3060E toc02 DE = RE = VCC 800 60 MAX3060E toc01 950 RECEIVER OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE RECEIVER OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE MAX3060E toc03 NO-LOAD SUPPLY CURRENT vs. TEMPERATURE NO-LOAD SUPPLY CURRENT (µA) MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT 14 12 10 8 6 4 2 -40 -15 10 35 TEMPERATURE (°C) 8 60 85 0 0 1 2 3 OUTPUT LOW VOLTAGE (V) 4 5 0 1 2 3 OUTPUT HIGH VOLTAGE (V) _______________________________________________________________________________________ 4 5 ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT 3.0 2.5 2.0 1.5 1.0 0.35 0.30 0.25 0.20 IRO = -8mA 4.0 3.8 3.6 3.4 0 3.2 0.10 -40 -15 10 35 60 85 -40 -15 10 35 60 -40 85 -15 10 35 60 TEMPERATURE (°C) TEMPERATURE (°C) RECEIVER PROPAGATION DELAY (MAX3060E/MAX3061E) vs. TEMPERATURE RECEIVER PROPAGATION DELAY (MAX3062E) vs. TEMPERATURE DRIVER PROPAGATION DELAY (MAX3060E) vs. TEMPERATURE 50 45 40 35 CL = 15pF 65 60 55 50 45 40 35 1.80 1.76 1.74 1.72 1.70 1.68 1.66 30 30 1.64 25 25 1.62 20 20 -15 10 35 60 1.60 -40 85 -15 10 35 60 85 -15 10 35 60 85 TEMPERATURE (°C) TEMPERATURE (°C) DRIVER PROPAGATION DELAY (MAX3061E) vs. TEMPERATURE DRIVER PROPAGATION DELAY (MAX3062E) vs. TEMPERATURE DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE 520 500 480 460 440 30 Rt = 54Ω 25 20 15 10 5 420 -15 10 35 TEMPERATURE (°C) 60 85 Rt = 54Ω 3.2 3.0 2.8 2.6 2.4 2.2 2.0 0 400 3.4 MAX3060E toc12 Rt = 54Ω OUTPUT VOLTAGE (V) MAX3060E toc10 540 -40 -40 TEMPERATURE (°C) PROPAGATION DELAY (ns) -40 Rt = 54Ω 1.78 PROPAGATION DEALY (µs) 55 MAX3060E toc08 60 70 PROPAGATION DEALY (ns) MAX3060E toc07 CL = 15pF 65 85 MAX3060E toc09 TEMPERATURE (°C) 70 PROPAGATION DEALY (ns) 0.40 4.2 0.15 0.5 PROPAGATION DELAY (ns) IRO = 8mA 0.45 OUTPUT HIGH VOLTAGE (V) 3.5 MAX3060E toc05 4.0 0.50 MAX3060E toc11 SHUTDOWN CURRENT (nA) 4.5 OUTPUT LOW VOLTAGE (V) MAX3060E toc04 5.0 RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE MAX3060E toc06 SHUTDOWN CURRENT vs. TEMPERATURE -40 -15 10 35 TEMPERATURE (°C) 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 9 MAX3060E/MAX3061E/MAX3062E Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) DRIVER OUTPUT CURRENT vs. OUTPUT LOW VOLTAGE 1 0.1 MAX3060E toc14 120 80 70 DRIVER OUTPUT CURRENT (mA) 10 90 DRIVER OUTPUT CURRENT (mA) MAX3060E toc13 100 DRIVER OUTPUT CURRENT vs. OUTPUT HIGH VOLTAGE 60 50 40 30 20 MAX3060E toc15 DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE OUTPUT CURRENT (mA) MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT 100 80 60 40 20 10 0.01 0 0 0 1 2 3 4 5 0 6 DIFFERENTIAL OUTPUT VOLTAGE (V) 2 4 6 8 10 -8 12 OUTPUT LOW VOLTAGE (V) RECEIVER PROPAGATION DELAY (MAX3060E/MAX3061E) -4 -2 0 2 4 6 OUTPUT HIGH VOLTAGE (V) DRIVER PROPAGATION DELAY (MAX3061E) RECEIVER PROPAGATION DELAY (MAX3062E) MAX3060E toc16 -6 MAX3060E toc18 MAX3060E toc17 DI 5V/div VA - VB 1V/div VA - VB 1V/div RO 5V/div RO 5V/div VA - VB 2V/div 20ns/div 20ns/div 1µs/div DRIVER PROPAGATION DELAY (MAX3060E) DRIVER PROPAGATION DELAY (MAX3061E) DRIVER PROPAGATION DELAY (MAX3062E) MAX3060E toc20 MAX3060E toc19 MAX3060E toc21 DI 5V/div DI 5V/div VA - VB 2V/div VA - V B 2V/div 2µs/div 10 10ns/div 20ns/div ______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT PIN NAME FUNCTION 1 RO Receiver Output. When RE is low and when A - B ≥ -50mV, RO is high; if A - B ≤ -200mV, RO is low. RO is high impedance when RE is high. 2 RE Receiver Output Enable. Drive RE low to enable RO; RO is high impedance when RE is high. Drive RE high and DE low to enter low-power shutdown mode. RE is a hot-swap input and reverts to a standard CMOS input after the first low transition. 3 DE Driver Output Enable. Drive DE high to enable driver outputs. Driver outputs are high impedance when DE is low. Drive RE high and DE low to enter low-power shutdown mode. DE is a hot-swap input and reverts to a standard CMOS input after the first high transition. 4 DI Driver Input. With DE high, a low on DI forces the noninverting output low and the inverting output high. Similarly, a high on DI forces the noninverting output high and the inverting output low. 5 GND 6 A Noninverting Receiver Input and Noninverting Driver Output 7 B Inverting Receiver Input and Inverting Driver Output 8 VCC Ground Positive Supply. Bypass with a 0.1µF capacitor to GND. Detailed Description The MAX3060E/MAX3061E/MAX3062E high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature fail-safe circuitry, which 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). All devices have a hot-swap input structure that prevents disturbances on the differential signal lines when a circuit board is plugged into a hot backplane (see the Hot-Swap Capability section). The MAX3060E features a reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 115kbps (see the Reduced EMI and Reflections section). The MAX3061E is also slew-rate limited, transmitting up to 500kbps. The MAX3062E driver is not slew-rate limited, allowing transmit speeds up to 20Mbps. The MAX3060E/MAX3061E/ MAX3062E are half-duplex transceivers. All of these parts operate from a single +5V supply. Drivers are output short-circuit current limited. Thermalshutdown circuitry protects drivers against excessive power dissipation. When activated, the thermal-shutdown circuitry places the driver outputs into a highimpedance state. Receiver Input Filtering The receivers of the MAX3060E and MAX3061E incorporate input filtering in addition to input hysteresis. This filtering enhances noise immunity with differential signals that have very slow rise and fall times. Receiver propagation delay increases by 2ns due to this filtering. Fail-Safe The MAX3060E family of devices guarantee a logic-high 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 setting the receiver threshold between -50mV and -200mV. If the differential receiver input voltage (A - B) is greater than or equal to -50mV, RO is logic high. If A - B is less than or equal to -200mV, RO is logic low. In the case of a terminated bus with all transmitters disabled, the receiver’s differential input voltage is pulled to 0V by the termination. In the case of an unterminated bus with all transmitters disabled, the receiver’s differential input voltage is pulled to 0V by the receiver’s input resistors. With the receiver thresholds of the MAX3060E family, this results in a logic high output with a 50mV minimum input noise margin. Unlike previous fail-safe devices, the -50mV to -200mV threshold complies with the ±200mV EIA/TIA-485 standard. ______________________________________________________________________________________ 11 MAX3060E/MAX3061E/MAX3062E Pin Description MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT Functional Tables Table 2. Receiver Functional Table Table 1. Transmitter Functional Table TRANSMITTING RECEIVING INPUTS OUTPUTS RE DE DI B A RE INPUTS DE A-B OUTPUT RO X 1 1 0 1 0 X ≥ -0.05V 1 0 X 1 0 1 0 0 X ≤ -0.2V 0 0 X High-Z High-Z 0 X Open/shorted 1 1 0 X 1 1 X High-Z 1 0 X Shutdown Shutdown* X = Don’t care. *Shutdown mode, driver and receiver outputs are high impedance. Hot-Swap Capability Hot-Swap Input When circuit boards are inserted into a hot or powered backplane, differential disturbances to the data bus can lead to data errors. Upon initial circuit board insertion, the data communication processor undergoes its own powerup sequence. During this period, the processor’s logicoutput drivers are high impedance and are unable to drive the DE and RE inputs of the MAX306_E to a defined logic level. Leakage currents up to ±10µA from the highimpedance state of the processor’s logic drivers could cause standard CMOS enable inputs of a transceiver to drift to an incorrect logic level. Additionally, parasitic circuit board capacitance could cause coupling of VCC or GND to the enable inputs. Without the hot-swap capability, these factors could improperly enable the transceiver’s driver or receiver. When VCC rises, an internal pulldown circuit holds DE low for at least 10µs and until the current into DE exceeds 200µA. After the initial positive transition, the pulldown circuit becomes transparent, resetting the hot-swap tolerable input. Hot-Swap Input Circuitry These devices’ enable inputs feature hot-swap capability. At the input there are two NMOS devices, M1 and M2 (Figure 10). When VCC ramps from zero, an internal 10µs timer turns on M2 and sets the SR latch, which also turns on M1. Transistors M2, a 300µA current sink, and M1, a 30µA current sink, pull DE to GND through an 8kΩ resistor. M2 is designed to pull DE to the disabled state against an external parasitic capacitance up to 100pF that can drive DE high. After 10µs, the timer deactivates M2 while M1 remains on, holding DE low against threestate leakages that can drive DE high. M1 remains on 12 until an external source overcomes the required input current. At this time, the SR latch resets and M1 turns off. When M1 turns off, DE reverts to a standard, highimpedance CMOS input. Whenever VCC drops below 1V, the hot-swap input is reset. For RE, there is a complementary circuit employing two PMOS devices pulling RE to VCC. VCC 10µs TIMER SR LATCH TIMER 8kΩ DE (HOT SWAP) DE 30µA M1 300µA M2 Figure 10. Simplified Structure of the Driver Enable Input (DE) ______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E Hot-Swap Line Transient The circuit of Figure 11 shows a typical offset termination used to guarantee a greater than 200mV offset when a line is not driven (the 50pF represents the minimum parasitic capacitance that would exist in a typical application). During a hot-swap event when the driver is connected to the line and is powered up, the driver must not cause the differential signal to drop below 200mV. Figures 12, 13, and 14 show the results of the MAX3060E during power-up for three different V CC ramp rates (0.1V/µs, 1V/µs, and 10V/µs). The photos show the VCC ramp, the single-ended signal on each side of the 100Ω termination, as well as the differential signal across the termination. 5V 0 VCC A 200mV/div B 200mV/div 238mV 20mV/div A-B 40µs/div ±15kV 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 MAX3060E family’s receiver inputs/driver outputs (A, B) have extra protection against static electricity found in normal operation. Maxim’s engineers developed stateof-the-art structures to protect these pins against ±15kV ESD without damage. After an ESD event, the devices continue working without latchup. ESD protection can be tested in several ways. The receiver inputs are characterized for protection to the following: • ±15kV using the Human Body Model • ±7kV using the Contact Discharge method specified in IEC 1000-4-2 (formerly IEC 801-2) • ±7kV using the Air-Gap Discharge method specified in IEC 1000-4-2 (formerly IEC 801-2) Figure 12. Differential Power-Up Glitch (0.1V/µs) 5V VCC 0 A 20mV/div B 20mV/div 238mV 20mV/div A-B 2µs/div Figure 13. Differential Power-Up Glitch (1V/µs) 5.0V 5V VCC 0 1kΩ VCC A DI VCC OR GND A 0.1kΩ 50mV/div 50pF B 50mV/div B 1kΩ 238mV 20mV/div A-B 200ns/div Figure 11. Typical Offset Termination Figure 14. Differential Power-Up Glitch (10V/µs) ______________________________________________________________________________________ 13 MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT 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 15a shows the Human Body Model, and Figure 15b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5kΩ resistor. IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The main difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2. Because series resistance is lower in the IEC 1000-4-2 ESD test model (Figure 16), the ESD withstand voltage measured to this standard is generally lower than that measured using the Human Body Model. 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 ESD testing uses a 200pF storage capacitor and zero-discharge resistance. It mimics the stress caused by handling during manufacturing and assembly. 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 1000-4-2. RC 1MΩ CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE The standard RS-485 receiver input impedance is 12kΩ (one-unit load), and the standard driver can drive up to 32-unit loads. The MAX3060E family of transceivers have a 1/8-unit-load receiver input impedance (96kΩ), allowing up to 256 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 32 unit loads or less can be connected to the line. Reduced EMI and Reflections The MAX3060E and MAX3061E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 17 shows the driver output waveform and its Fourier analysis of a 25kHz 14 DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR Figure 15a. Human Body ESD Test Model IP 100% 90% Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES 36.8% 10% 0 0 tRL TIME tDL CURRENT WAVEFORM Figure 15b. Human Body Current Waveform RC 50MΩ to 100MΩ CHARGE-CURRENT LIMIT RESISTOR Applications Information 256 Transceivers on the Bus Cs 100pF RD 1.5kΩ HIGHVOLTAGE DC SOURCE Cs 150pF RD 330Ω DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Figure 16. IEC 1000-4-2 ESD Test Model signal transmitted by a MAX3062E. High-frequency harmonic components with large amplitudes are evident. Figure 18 shows the same signal displayed for a MAX3061E transmitting under the same conditions. ______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT In general, a transmitter’s rise time relates directly to the length of an unterminated stub, which can be driven with only minor waveform reflections. The following equation expresses this relationship conservatively: Length = tRISE / (10 x 1.5ns/ft) where tRISE is the transmitter’s rise time. For example, the MAX3060E’s rise time is typically 1850ns, which results in excellent waveforms with a stub length up to 123ft. A system can work well with longer unterminated stubs, even with severe reflections, if the waveform settles out before the UART samples them. 20dB/div 0 125kHz/div 1.25MHz Figure 17. Driver Output Waveform and FFT Plot of MAX3062E Transmitting a 25kHz Signal Low-Power Shutdown Mode Low-power shutdown mode is initiated by bringing both RE high and DE low. In shutdown, the devices typically draw only 1nA of supply current. RE and DE can be driven simultaneously. The parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown. Enable times t_ ZH and t_ ZL in the Switching Characteristics tables assume the part was not in a lowpower shutdown state. Enable times t_ZH(SHDN) and t_ZL(SHDN) assume the parts were shut down. It takes drivers and receivers longer to become enabled from low-power shutdown mode (t_ZH(SHDN), t_ZL(SHDN)) than from driver/receiver-disable mode (t_ZH, t_ZL). 20dB/div 0 125kHz/div 1.25MHz Figure 18. Driver Output Waveform and FFT Plot of MAX3061E Transmitting a 25kHz Signal 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 protection after a 20µs delay against short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). The second, a thermal shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature becomes excessive. 20dB/div 0 125kHz/div 1.25MHz Figure 19. Driver Output Waveform and FFT Plot of MAX3060E Transmitting a 25kHz Signal ______________________________________________________________________________________ 15 MAX3060E/MAX3061E/MAX3062E Figure 18’s high-frequency harmonic components are much lower in amplitude, compared with Figure 17’s, and the potential for EMI is significantly reduced. Figure 19 shows the same signal displayed for a MAX3060E transmitting under the same conditions. Figure 19’s high-frequency harmonic components are even lower. MAX3060E/MAX3061E/MAX3062E ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT 120Ω 120Ω DI DE B B D D DI DE RO RE A B A B A A R R RO RE R R D D MAX3060E/MAX3061E/ MAX3062E (HALF-DUPLEX) DI DE RO RE DI DE RO RE Figure 20. Typical Half-Duplex RS-485 Network Typical Applications The MAX3060E family of transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figure 20 shows a typical network application circuit. To minimize reflections, 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 MAX3060E and MAX3061E are more tolerant of imperfect termination. 16 Chip Information TRANSISTOR COUNT: 669 PROCESS: CMOS ______________________________________________________________________________________ ±15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT SOT23, 8L.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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX3060E/MAX3061E/MAX3062E Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)