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® SP3481/SP3485 +3.3V Low Power Half-Duplex RS-485 Transceivers with 10Mbps Data Rate ■ RS-485 and RS-422 Transceivers ■ Operates from a single +3.3V supply Interoperable with +5.0V logic ■ Driver/Receiver Enable Low Power Shutdown Mode (SP3481) -7V to +12V Common-Mode Input Voltage Range ■ Allows up to 32 transceivers on the serial bus ■ Compatibility with the industry standard 75176 pinout ■ Driver Output Short-Circuit Protection DESCRIPTION The SP3481 and the SP3485 are a family of +3.3V low power half-duplex transceivers that meet the specifications of the RS-485 and RS-422 serial protocols. These devices are pin-to- pin compatible with the Sipex SP481, SP483, and SP485 devices as well as popular industry standards. The SP3481 and the SP3485 feature Sipex's BiCMOS process, allowing low power operation without sacrificing performance. The SP3481 and SP3485 meet the electrical specifications of RS-485 and RS-422 serial protocols up to 10Mbps under load. The SP3481 is equipped with a low power Shutdown mode. RO RE RE DE DI 1 2 3 4 R D Vcc 8 7 B 6 A 5 GND SP3481 and SP3485 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation 1 ■ ■ ■

ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. VCC ............................................................................................. +6.0V Input Voltages Logic ..................................................... -0.3V to +6.0V Drivers ................................................... -0.3V to +6.0V Receivers ............................................................ ±15V Output Voltages Drivers .................................................................. ±15V Receivers .............................................. -0.3V to +6.0V Storage Temperature ................................................ .-65˚C to +150˚C Power Dissipation per Package 8-pin NSOIC (derate 6.90mW/oC above +70oC) ..................... 600mW 8-pin PDIP (derate 11.8mW/oC above +70oC) ...................... 1000mW SPECIFICATIONS TAMB = TMIN to TMAX and VCC = +3.3V ± 5% unless otherwise noted. TYP. MIN. PARAMETERS SP3481/SP3485 DRIVER DC Characteristics Differential Output Voltage Differential Output Voltage Differential Output Voltage Change in Magnitude of Driver Differential Output Voltage for Complimentary States Driver Common-Mode Output Voltage Input High Voltage Input Low Voltage Input Current Driver Short-Circuit Current VOUT = HIGH VOUT = LOW SP3481/SP3485 DRIVER AC Characteristics Maximum Data Rate Driver Input to Output, tPLH Driver Input to Output, tPHL Differential Driver Skew Driver Rise or Fall Time Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High SP3481/SP3485 RECEIVER DC Characteristics Differential Input Threshold Input Hysteresis Output Voltage High Output Voltage Low Three-State (High Impedance) Output Current Input Resistance Input Current (A, B); VIN = 12V Input Current (A, B); VIN = -7V Short-Circuit Current GND 2 1.5 2.0 10 20 20 -0.2 12 7 40 40 2 5 52 60 40 60 20 15 VCC-0.4 MAX. UNITS CONDITIONS VCC VCC VCC 0.2 3 0.8 ±10 Volts Unloaded; R = ∞; Figure 1 Volts with load; R = 50Ω; (RS-422); Figure 1 Volts with load; R = 27Ω; (RS-485); Figure 1 Volts R = 27Ω or R = 50Ω; Figure 1 Volts R = 27Ω or R = 50Ω; Figure 1 Volts Applies to DE, DI, RE Volts Applies to DE, DI, RE µA Applies to DE, DI, RE ±250 ±250 mA mA -7V ≤ VO ≤ +12V -7V ≤ VO ≤ +12V Mbps RE = VCC, DE = VCC 60 60 10 20 120 120 120 120 +0.2 0.4 +1 1.0 -0.8 60 ns ns ns ns ns ns ns ns Volts mV Volts Volts µA kΩ mA mA mA Figures 2 and 8 Figures 2 and 8 tDO1 - tDO2 Figures 2 and 9 From 10% to 90% ; Figures 3 and 9 Figures 4 and 10 Figures 5 and 10 Figures 5 and 10 Figures 4 and 10 -7V ≤ VCM ≤ +12V VCM = 0V VID = +200mV, -1.5mA VID = -200mV, 2.5mA 0V ≤ VO ≤ VCC; RE = VCC -7V ≤ VCM ≤ +12V DE = 0V, VCC = 0V or 3.6V, VIN = 12V DE = 0V, VCC = 0V or 3.6V, VIN = -7V 0V ≤ VCM ≤ VCC 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation 2

SPECIFICATIONS (continued) TAMB = TMIN to TMAX and VCC = +3.3V ± 5% unless otherwise noted. TYP. PARAMETERS SP3481/SP3485 RECEIVER MIN. MAX. UNITS CONDITIONS AC Characteristics Maximum Data Rate Receiver Input to Output, tPLH 10 40 Receiver Input to Output, tPHL 40 50 Differential Receiver Skew Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable from Low Receiver Disable from High SP3481 Shutdown Timing Time to Shutdown Driver Enable from Shutdown to Output High Driver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low POWER REQUIREMENTS Supply Current SP3481/3485 No Load SP3481 Shutdown Mode 70 70 4 35 35 35 35 75 65 65 50 50 100 70 100 70 60 60 60 60 200 150 150 200 200 1000 800 2000 1500 10 Mbps ns ns RE = 0V, DE = 0V Figures 6 and 11 TAMB = +25oC, VCC = +3.3V, Figures 6 and 11 ns ns ns ns ns ns ns ns ns ns ns ns µA µA µA Figures 6 and 11 TAMB = +25oC, VCC = +3.3V, Figures 6 and 11 tRSKEW = tRPHL - tRPLH, Figures 6 and 11 Figures 7 and 12; S1 closed, S2 open Figures 7 and 12; S2 closed, S1 open Figures 7 and 12; S1 closed, S2 open Figures 7 and 12; S2 closed, S1 open RE = 3.3V, DE = 0V Figures 4 and 10 Figures 5 and 10 Figures 7 and 12; S2 closed, S1 open Figures 7 and 12; S1 closed, S2 open RE, DI = 0V or VCC; DE = VCC RE = 0V, DI = 0V or VCC; DE = 0V DE = 0V, RE=VCC 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation 3

RO 1 RE 2 DE 3 DI 4 R 8 VCC 7 B 6 A D SP485 5 GND Top View SP3481/SP3485 Pinout (Top View) PIN FUNCTION Pin 1 – RO – Receiver Output. Pin 2 – RE – Receiver Output Enable Active LOW. Pin 3 – DE – Driver Output Enable Active HIGH. Pin 4 – DI – Driver Input. Pin 5 – GND – Ground Connection. Pin 6 – A – Driver Output/Receiver Input Non-inverting. Pin 7 – B – Driver Output/Receiver Input Inverting. Pin 8 – VCC DESCRIPTION Receivers The SP3481 and the SP3485 are 2 members in the family of +3.3V low power half-duplex transceivers that meet the specifications of the RS-485 and RS-422 serial protocols. These devices are pin-to-pin compatible with the Sipex SP481, SP483, and SP485 devices as well as popular industry standards. The SP3481 and the SP3485 feature Sipex's BiCMOS process allowing low power operation without sacrificing performance. Drivers The driver outputs of the SP3481 and SP3485 are differential outputs meeting the RS-485 and RS-422 standards. The typical voltage output swing with no load will be 0 Volts to +3.3 Volts. With a load of 54Ω across the differential outputs, the drivers maintain greater than 1.5V voltage levels. The drivers of the SP3481 and SP3485 have an enable control line which is active HIGH. A logic HIGH on DE (pin 3) will enable the differential driver outputs. A logic LOW on DE (pin 3) will tri-state the driver outputs. The tranceivers in the SP3481 and SP3485 operate up to 10Mbps. The 250mA ISC maximum limit on the driver output allows the SP3481 and the SP3485 to withstand an infinite short circuit over the -7.0V to +12.0V common mode range without catastrophic damage to the IC. The SP3481 and SP3485 receivers have differential inputs with an input sensitivity as low as ±200mV. Input impedance of the receivers is typically 15kΩ (12kΩ minimum). A wide common mode range of -7V to +12V allows for large ground potential differences between systems. The receivers of the SP3481 and SP3485 have a tri-state enable control pin. A logic LOW on RE (pin 2) will enable the receiver, a logic HIGH on RE (pin 2) will disable the receiver. The receivers of the SP3481 and SP3485 operate up to 10Mbps. The receiver for each of the three devices is equipped with fail-safe. Fail-safe guarantees that the receiver output will be in a HIGH state when the input is left unconnected. Shutdown Mode for the SP3481 The SP3481 is equipped with a Shutdown mode. To enable the Shutdown state, both the driver and receiver must be disabled simultaneously. A logic LOW on DE (pin 3) and a logic HIGH on RE (pin 2) will put the SP3481 into Shutdown mode. In Shutdown, supply current will drop to typical 1µA, 10µA maximum. 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation 4

D VOD VCC R R VOC GENERATOR (NOTE 1) 50Ω VDM RL = 27Ω OUT CL = 15pF (NOTE 2) S1 D VCC VOM = 1.5V VOH + VOL 2 Figure 1. Driver DC Test Load Circuit Figure 2. Driver Propagation Delay Test Circuit CL RL = 60Ω OUT GENERATOR (NOTE 1) 50Ω D VCC S1 D CL = 50pF (NOTE 2) OUT RL = 110Ω GENERATOR (NOTE 1) 50Ω CL = 15pF (NOTE 2) VOM = 1.5V VOH + VOL 2 Figure 3. Driver Differential Output Delay and Transition Time Circuit Figure 4. Driver Enable and Disable Timing Circuit, Output HIGH VCC RL = 110Ω OUT S1 CL = 50pF (NOTE 2) 0V OR 3V D GENERATOR (NOTE 1) 50Ω GENERATOR (NOTE 1) 50Ω 1.5V 0V VID R OUT CL = 15pF (NOTE 2) VOM = VCC 2 Figure 5. Driver Enable and Disable Timing Circuit, Output LOW Figure 6. Receiver Propagation Delay Test Circuit S3 1.5V -1.5V VID R GENERATOR (NOTE 1) 50Ω 1k CL = 15pF (NOTE 2) S1 S2 VCC Figure 7. Receiver Enable and Disable Timing Circuit INPUTS OUTPUTS INPUTS OUTPUTS LINE 1 1 0 1 0 X RE DE DI CONDITION B 0 X 1 X X Z No Fault No Fault X Table 1. Transmit Function Truth Table A 1 0 Z RE 0 0 0 1 DE 0 0 0 0 A - B +0.2V -0.2V Inputs Open X Table 2. Receive Function Truth Table R 1 0 1 Z 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation 5

INPUT Y OUTPUT Z OUTPUT 3V 0V VOH VOL VOH VOL 1.5V tPLH 1.5V tPHL VOM VOM tPHL tPLH VOM VOM VOM = VOH + VOL 2 ≈ 1.5V IN 1.5V 1.5V tDO1 tDO2 90% 90% OUT 50% 10% tTD 50% 10% tTD 3V 0V 2.0V -2.0V Figure 8. Driver Propagation Delay Waveforms Figure 9. Driver Differential Output Delay and Transition Time Waveforms DE OUTPUT HIGH OUTPUT LOW 3V 0V VOH 0V VCC VOL 1.5V tPZH 1.5V tPHZ VOM 0.25V tPZL tPLZ VOM 0.25V VOM = VOH + VOL 2 ≈ 1.5V INPUT OUTPUT 3V 0V VCC 0V 1.5V tRPLH 1.5V tRPHL VOM VOM VOM = VCC 2 Figure 10. Driver Enable and Disable Timing Waveforms Figure 11. Receiver Propagation Delay Waveforms S1 is open S2 is closed S3 = 1.5V 1.5V tPRHZ 10% 1.5V tPRZH tPRSH S1 is closed S2 is open S3 = -1.5V 1.5V tPRLZ 10% 1.5V tPRZL tPRSL 1.5V 3V 0V VCC VOL RE 1.5V OUTPUT RE OUTPUT 3V 0V VOH 0V Figure 12. Receiver Enable and Disable Waveforms NOTE 1: The input pulse is supplied by a generator with the following characteristics: PRR=250KHz, 50% duty cycle, tr < 6.0ns, Z0=50Ω. NOTE 2: CL includes probe and stray capacitance. 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation 6

PACKAGE: PLASTIC DUAL–IN–LINE (NARROW) D1 = 0.005" min. (0.127 min.) D E1 E A1 = 0.015" min. (0.381min.) A = 0.210" max. (5.334 max). A2 L B1 B e = 0.100 BSC (2.540 BSC) ALTERNATE END PINS (BOTH ENDS) C Ø eA = 0.300 BSC (7.620 BSC) DIMENSIONS (Inches) Minimum/Maximum 8–PIN (mm) A2 B B1 C D E E1 L Ø 0.115/0.195 (2.921/4.953) 0.014/0.022 (0.356/0.559) 0.045/0.070 (1.143/1.778) 0.008/0.014 (0.203/0.356) 0.355/0.400 (9.017/10.160) 0.300/0.325 (7.620/8.255) 0.240/0.280 (6.096/7.112) 0.115/0.150 (2.921/3.810) 0°/ 15° (0°/15°) 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation 7

PACKAGE: PLASTIC SMALL OUTLINE (SOIC) (NARROW) E H A A1 D e B h x 45° Ø L DIMENSIONS (Inches) Minimum/Maximum 8–PIN (mm) A A1 B D E e H h L Ø 0.053/0.069 (1.346/1.748) 0.004/0.010 (0.102/0.249 0.014/0.019 (0.35/0.49) 0.189/0.197 (4.80/5.00) 0.150/0.157 (3.802/3.988) 0.050 BSC (1.270 BSC) 0.228/0.244 (5.801/6.198) 0.010/0.020 (0.254/0.498) 0.016/0.050 (0.406/1.270) 0°/8° (0°/8°) 10/15/02 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation 8

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