IL3185/IL3122 Low Cost Passive Input RS-485 and RS-422 Isolated Transceivers Functional Diagrams Features • 5 Mbps data rate • 3 V to 5 V power supplies • Supports up to 32 nodes • 15 kV bus ESD protection • 2500 VRMS isolation per UL 1577 • 20 kV/µs typical common mode rejection • No carrier or clock for low EMI emissions and susceptibility • −40°C to +85°C temperature range • Thermal shutdown protection • UL 1577 recognized; IEC 60747-5-5 (VDE 0884) certified • 0.15", 0.3" or True 8™ mm 16-pin SOIC packages DE VCOIL1 D VCOIL2 A B R RE IL3185 DE Applications • P.O.S. systems • Security networks • Building environmental controls • Industrial control networks • Gaming systems • Factory automation VCOIL1 Y Z D VCOIL2 A B R RE IL3122 IL3185 Truth Table DE D R V(A-B) ≥ 200 mV H H H ≤−200 mV H L L ≥ 200 mV L X H ≤−200 mV L X L X X X Z Open L X H Z = High Impedance X = Irrelevant IL3122 Receiver RE R V(A-B) H Z X L H ≥ 200 mV L L ≤−200 mV L H Open RE L L L L H L Description The IL3185 and IL3122 are galvanically isolated, differential bus transceivers designed for bidirectional data communication over balanced transmission lines. The devices use NVE’s patented* IsoLoop spintronic Giant Magnetoresistance (GMR) technology. The IL3185 delivers at least 1.5 V into a 54 Ω load, and the IL3122 at least 2 V into a 100 Ω load for excellent data integrity over long cables. These devices are also compatible with 3 V input supplies, allowing interface to standard microcontrollers without additional level shifting. Mode Drive Drive Receive Receive X Receive IL3122 Driver DE D L X H H H L V(Y-Z) Z ≥ 200 mV ≤−200 mV Both the IL3185 and IL3122 have current limiting and thermal shutdown features to protect against output short circuits and bus contentions that may cause excessive power dissipation. The receivers also incorporate a “fail-safe if open” design, ensuring a logic high on R if the bus lines are disconnected or “floating.” Selection Table Model IL3185 IL3122 Full/Half Duplex half full No. of Devices Allowed on Bus 32 32 Data Rate Mbps 5 5 Fail-Safe yes yes IsoLoop® is a registered trademark of NVE Corporation. *U.S. Patent numbers 5,831,426; 6,300,617 and others. NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 REV. P Phone: (952) 829-9217 www.isoloop.com [email protected] ©NVE Corporation IL3185/IL3122 Absolute Maximum Ratings Operating at absolute maximum ratings will not damage the device. However, extended periods of operation at the absolute maximum ratings may affect performance and reliability. Parameters Symbol Min. Typ. Max. Storage Temperature TS −55 150 Ambient Operating Temperature TA −40 85 Voltage Range at A or B Bus Pins −7 12 Supply Voltage(1) VDD1, VDD2 −0.5 7 Digital Input Voltage −0.5 VDD+0.5 Digital Output Voltage −0.5 VDD+1 ESD Protection ±15 Input Current IIN −25 +25 ESD (all bus nodes) 15 Note 1. All voltage values are with respect to network ground except differential I/O bus voltages. Units °C °C V V V V kV mA kV Test Conditions HBM Recommended Operating Conditions Parameters Supply Voltage Ambient Operating Temperature Input Voltage at any Bus Terminal (separately or common mode) Input Threshold for Output Logic High Input Threshold for Output Logic Low Differential Input Voltage High-Level Output Current (Driver) High-Level Digital Output Current (Receiver) Low-Level Output Current (Driver) Low-Level Digital Output Current (Receiver) Ambient Operating Temperature Digital Input Signal Rise, Fall Times Symbol VDD1 VDD2 TA VI VIC IINH IINL VID IOH Min. 3.0 4.5 −40 Typ. −60 +12/−7 60 mA mA V mA IOH −8 8 mA IOL −60 60 mA IOL −8 8 mA TA tIR,tIF −40 85 1 °C µs Symbol CTI Min. ≥175 1000 Max. Units V VRMS 1.5 3.5 5 Max. 5.5 5.5 85 12 −7 0.8 Units Test Conditions V °C V Insulation Specifications Parameters Comparative Tracking Index Endurance Voltage AC (Maximum Working Voltage for Indefinite Life) DC Creepage Distance 0.15" SOIC (external) 0.3" SOIC Total Barrier Thickness (internal) Barrier Resistance(5) Barrier Capacitance(5) Leakage Current VIO Typ. VDC 1500 4.03 8.03 0.012 8.3 0.013 >1014 7 0.2 RIO CIO Test Conditions Per IEC 60112 At maximum operating temperature mm Per IEC 60601 mm Ω pF μA 500 V f = 1 MHz 240 VRMS, 60 Hz 2 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Safety Approvals IEC 60747-5-5 (VDE 0884) (File Number 5016933-4880-0001) • Working Voltage (VIORM) 600 VRMS (848 VPK); basic insulation; pollution degree 2 • Transient overvoltage (VIOTM) and surge voltage (VIOSM) 4000 VPK • Each part tested at 1590 VPK for 1 second, 5 pC partial discharge limit • Samples tested at 4000 VPK for 60 sec.; then 1358 VPK for 10 sec. with 5 pC partial discharge limit IEC 61010-1 (Edition 2; TUV Certificate Numbers N1502812; N1502812-101) Reinforced Insulation; Pollution Degree II; Material Group III Part No. Suffix -3 None Package SOIC Wide-body SOIC/True 8™ Working Voltage 150 VRMS 300 VRMS UL 1577 (Component Recognition Program File Number E207481) Each part tested at 3000 VRMS (4240 VPK) for 1 second; each lot sample tested at 2500 VRMS (3530 VPK) for 1 minute Soldering Profile Per JEDEC J-STD-020C, MSL 1 Electrostatic Discharge Sensitivity This product has been tested for electrostatic sensitivity to the limits stated in the specifications. However, NVE recommends that all integrated circuits be handled with appropriate care to avoid damage. Damage caused by inappropriate handling or storage could range from performance degradation to complete failure. 3 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 IL3185-3 Pin Connections (0.15" SOIC Package) Input power supply 1 VDD1 2 GND1 3 R 4 RE Read enable (if RE is high, R is high impedance) 5 DE Drive enable 6 VCOIL1 7 D 8 NC 9 GND2 10 NC 11 VDD2 12 A Non-inverting bus line 13 B Inverting bus line 14 NC 15 GND2 Ground return for VDD2 (internally connected to pin 9) 16 VCOIL2 Coil for R Ground return for VDD1 Output data from bus Coils for DE and D (connect to VDD1) VDD1 VCOIL2 GND1 GND2 R NC Data input to bus No internal connection RE B Ground return for VDD2 (internally connected to pin 15) DE A VDD2 VCOIL1 No internal connection Output power supply NC D NC GND2 IL3185-3 No internal connection IL3122-3 Pin Connections (0.15" SOIC Package) 1 VDD1 Input power supply 2 GND1 Ground return for VDD1 3 R 4 Output data from bus Read enable (if RE is high, R is high impedance) RE 5 DE 6 VCOIL1 Drive enable 7 D 8 NC 9 GND2 10 Y 11 VDD2 Coils for DE and D (connect to VDD1) VDD1 VCOIL2 GND1 GND2 R A No internal connection RE B Ground return for VDD2 (internally connected to pin 15) DE Z Data input to bus Output power supply 12 Z Inverting driver bus line 13 B Inverting receiver bus line 14 A Non-inverting receiver bus line 15 GND2 Ground return for VDD2 (internally connected to pin 9) 16 VCOIL2 Coil for R VDD2 VCOIL1 Non-inverting driver bus line Y D NC GND2 IL3122-3 4 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 IL3185 Pin Connections (0.3" SOIC Package) Input power supply 1 VDD1 2 GND1 3 R 4 RE Read enable (if RE is high, R is high impedance) 5 DE Drive enable 6 VCOIL1 7 D Ground return for VDD1 Output data from bus Coils for DE and D (connect to VDD1) Data input to bus VDD1 VCOIL2 GND1 GND2 R 8 GND1 Internally connected to pin 2 for 0.3" package; no internal connection on 0.15" IL3285-3 9 GND2 Ground return for VDD2 (internally connected to pin 15) 10 NC 11 VDD2 12 A Non-inverting bus line 13 B Inverting bus line 14 NC RE B DE A VCOIL1 No internal connection Output power supply 15 GND2 16 VCOIL2 Coil for R VDD2 D NC GND2 GND1 No internal connection Ground return for VDD2 (internally connected to pin 9) NC IL3185 IL3122 Pin Connections (0.3" SOIC Package) 1 VDD1 2 GND1 3 R 4 RE Read enable (if RE is high, R is high impedance) 5 DE Drive enable 6 VCOIL1 7 D Input power supply Ground return for VDD1 Output data from bus Coils for DE and D (connect to VDD1) Data input to bus 8 GND1 Internally connected to pin 2 for 0.3" package; no internal connection on 0.15" IL3122-3 9 GND2 Ground return for VDD2 (internally connected to pin 15) 10 Y 11 VDD2 12 Z Inverting driver bus line 13 B Inverting receiver bus line 14 A Non-inverting receiver bus line 15 GND2 Ground return for VDD2 (internally connected to pin 9) 16 VCOIL2 Coil for R VDD1 VCOIL2 GND1 GND2 R A RE B DE Z VDD2 VCOIL1 Non-inverting driver bus line Output power supply D Y GND2 GND1 IL3122 5 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Driver Section Electrical Specifications (VDD1 = 3 V − 5.5 V; VDD2 = 4.5 V − 5.5 V; T = −40°C − 85°C unless otherwise stated) Parameters Symbol Min. Typ. Max. Units Test Conditions Coil Input Resistance RCOIL 47 85 112 Ω T = 25°C Coil Input Resistance RCOIL 31 85 128 Ω T = −40°C − 85°C Coil Resistance Temperature Coefficient TC RCOIL 0.2 0.25 Ω/°C Coil Inductance LCOIL 9 nH High Level Input Current IINH 0.5 1 mA tIR = tIF = 3 ns; CBOOST = 16 pF Low Level Input Current IINL 3.5 5 mA Output voltage VDD V IO = 0 Differential Output Voltage |VOD1| VDD V IO = 0 Differential Output Voltage |VOD2| 2 3 V RL = 100 Ω, VDD = 5 V Differential Output Voltage(6) VOD3 1.5 2.3 V RL = 54 Ω, VDD = 5 V Change in Magnitude(7) of Differential Δ|VOD| ±0.2 V RL = 54 Ω or 100 Ω Output Voltage Common Mode Output Voltage VOC 3 V RL = 54 Ω or 100 Ω Change in Magnitude(7) of Common Δ|VOC| 0.2 V RL = 54 Ω or 100 Ω Mode Output Voltage Output disabled, 1 mA Output Current(4) VO = 12 V −0.8 mA VO = −7 V |Short-circuit Output Current| IOS 60 250 mA −7 V < VO < 12 V IDD2 (VDD2 = +5 V) 6 7 No Load Supply Current mA IDD1 (VDD1 = +5 V) 2.5 3 (Outputs Enabled) No Load Supply Current (VDD1 = +3.3 V) IDD2 1.3 2 mA (Outputs Enabled) Common Mode Rejection |CMH|,|CML| 15 20 kV/μs VT = 300 Vpeak Switching Specifications (VDD1 = 5 V; VDD2 = 5 V; T = −40°C − 85°C) Parameters Symbol Min. Typ. Max. Units Data Rate 5 Mbps Differential Output Prop Delay tD(OD) 40 65 ns Pulse Skew(10) tSK(P) 6 15 ns Differential Output Rise and Fall Time tT(OD) 3 12 25 ns Drive Enable Time to High Level tPZH 25 40 ns Drive Enable Time to Low Level tPZL 25 40 ns Drive Disable Time from High Level tPHZ 25 40 ns Drive Disable Time from Low Level tPLZ 25 40 ns Skew Limit(3) tSK(LIM) 8 ns Switching Specifications (VDD1 = 3.3 V; VDD2 = 5 V; T = −40°C − 85°C) Parameters Symbol Min. Typ. Max. Units Data Rate 5 Mbps Differential Output Prop Delay tD(OD) 40 65 ns Pulse Skew(10) tSK(P) 6 20 ns Differential Output Rise and Fall Time tT(OD) 3 12 25 ns Drive Enable Time to High Level tPZH 25 40 ns Drive Enable Time to Low Level tPZL 25 40 ns Drive Disable Time from High Level tPHZ 25 40 ns Drive Disable Time from Low Level tPLZ 25 40 ns Skew Limit(3) tSK(LIM) 8 ns Test Conditions RL = 54 Ω; CL = 50 pF; Cboost = 16pF Test Conditions RL = 54 Ω; CL = 50 pF; Cboost = 16pF 6 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Receiver Section Electrical Specifications (VDD1 = 3 V − 5.5 V; VDD2 = 4.5 V − 5.5 V; T = −40°C − 85°C unless otherwise stated) Symbol Min. Typ. Max. Units Test Conditions 47 85 112 Ω T = 25°C Coil Resistance RCOIL 31 85 128 Ω T = −40°C − 85°C Coil Resistance Temperature Coefficient TC RCOIL 0.2 0.25 Ω/°C Positive-going Input Threshold VIT+ 0.2 V −7 V < VCM < 12 V Negative-going Input Threshold VIT− −0.2 V −7 V < VCM < 12 V Hysteresis Voltage (Vit+ − Vit−) VHYS 70 mV VCM = 0V, T = 25°C High Level Digital Output Voltage VOH VDD − 0.2 VDD − 0.2 V VID = 200 mV IOH = 4 mA Low Level Digital Output Voltage VOL 0.8 V VID = −200 mV IOL = 4 mA High impedance state output current IOZ 10 µA 0.4≤VO≤(VDD2 − 0.5) V Line Input Current(8) II 1 mA VI = 12 V −0.8 VI = −7 V Input Resistance rI 12 25 kΩ Parameters Switching Specifications (VDD1 = 5 V; VDD2 = 5 V; Cboost = 16pF; T = −40°C − 85°C) Symbol Min. Typ. Max. Units 5 Mbps Parameters Data Rate Propagation Delay(9) Pulse Skew(10) (3) Skew Limit Read Enable Time to High Level Read Enable Time to Low Level Read Disable Time from High Level Read Disable Time from Low Level tPD 50 85 ns tSK(P) 10 17 ns tSK(LIM) tPZH tPZL tPHZ tPLZ 2 4 4 4 4 8 40 40 40 40 ns ns ns ns ns Switching Specifications (VDD1 = 3.3 V; VDD2 = 5 V; Cboost = 16pF; T = −40°C − 85°C) Symbol Min. Typ. Max. Units 5 Mbps Parameters Data Rate Propagation Delay(9) Pulse Skew(10) (3) Skew Limit Read Enable Time to High Level Read Enable Time to Low Level Read Disable Time from High Level Read Disable Time from Low Level tPD 55 85 ns tSK(P) 12 20 ns tSK(LIM) tPZH tPZL tPHZ tPLZ 4 5 5 5 17 10 10 10 10 10 ns ns ns ns ns Test Conditions RL = 54 Ω, CL = 50 pF −1.5 ≤ VO ≤ 1.5 V, CL = 15 pF −1.5 ≤ VO ≤ 1.5 V, CL = 15 pF RL = 54 Ω, CL = 50 pF CL = 15 pF Test Conditions RL = 54 Ω, CL = 50 pF −1.5 ≤ VO ≤ 1.5 V, CL = 15 pF −1.5 ≤ VO ≤ 1.5 V, CL = 15 pF RL = 54 Ω, CL = 50 pF CL = 15 pF Notes (apply to both driver and receiver sections): 1. 2. 3. 4. 5. 6. 7. 8. All voltages are with respect to network ground except differential I/O bus voltages. Differential input/output voltage is measured at the non-inverting terminal A with respect to the inverting terminal B. Skew limit is the maximum difference in any two channels in one device. The power-off measurement in ANSI Standard EIA/TIA-422-B applies to disabled outputs only and is not applied to combined inputs and outputs. All typical values are at VDD1, VDD2 = 5 V or VDD1= 3.3 V and TA = 25°C. While −7 V < VCM < 12 V, the minimum VOD2 with a 54 Ω load is either ½ VOD1 or 1.5 V, whichever is greater. Δ|VOD| and Δ|VOC| are the changes in magnitude of VOD and VOC, respectively, that occur when the input is changed from one logic state to the other. This applies for both power on and power off; refer to ANSI standard RS-485 for exact condition. The EIA/TIA-422-B limit does not apply for a combined driver and receiver terminal. 9. Includes 10 ns read enable time. Maximum propagation delay is 25 ns after read assertion. 10. Pulse skew is defined as the |tPLH − tPHL| of each channel. 7 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Applications Information Input Resistor Values The IL3122 and IL3185 are current-mode devices. Changes in input coil current switch internal spintronic GMR sensors. Inputs are logically high when the coil voltage is high, that is when there is no coil current. A single resistor is required to limit the input coil current to the 5 mA threshold current. The absolute maximum current through any coil is 25 mA. Typical Input Resistor Values The table shows typical values for the external resistor in 5 V and 3 V logic systems. As always, these values as approximate and should be adjusted for temperature or other application specifics. If the expected temperature range is large, 1% tolerance resistors may provide additional design margin. 0.125W, 5% Resistor 510 Ω 820 Ω VCOIL 3.3 V 5V Boost Capacitor The boost capacitor in parallel with the current-limiting resistor boosts the instantaneous coil current at the signal transition. This ensures switching and reduces propagation delay and reduces pulse-width distortion. 50 1000 1000 Signal Rise/Fall Time (ns) 20 500 3 16 100 2500 CBoost (pF ) 210 5000 Select the value of the boost capacitor based on the rise and fall times of the signal driving the inputs. The instantaneous boost capacitor dV current is proportional to input edge speeds ( C dt ). Select a capacitor value based on the rise and fall times of the input signal to be isolated that provides approximately 20 mA of additional “boost” current. Figure 2 is a guide to boost capacitor selection. For high-speed logic signals (tr,tf < 10 ns), a 16 pF capacitor is recommended. The capacitor value is generally not critical; if in doubt, choose a higher value up to a maximum of 470 pF. Figure 2. Cboost Selector RS-485 and RS-422 Busses RS-485 and RS-422 are differential (balanced) data transmission standards for use over long distances or in noisy environments. RS-422 is an RS-485 subset, so RS-485 transceivers are also RS-422-compliant. RS-422 is a multi-drop standard allowing only one driver and up to 10 receivers on each bus (assuming unit load receivers). RS-485 is a true multipoint standard which allows up to 32 unit load devices (any combination of drivers and receivers) on each bus. To allow for multipoint operation, RS-485 requires drivers to handle bus contention without damage. Another important advantage of RS-485 is the extended common-mode range (CMR), which requires driver outputs and receiver inputs withstand +12 V to −7 V. RS-422 and RS-485 are intended for runs as long as 4,000 feet (1,200 m), so the wide CMR is necessary for ground potential differences, as well as voltages induced in the cable by external fields. Receiver Features IL3000 transceivers have differential input receivers for maximum noise immunity and common-mode rejection. Input sensitivity is ±200 mV as required by the RS-422 and RS-485 specifications. The receivers include a “fail-safe if open” function that guarantees a high level receiver output if the receiver inputs are unconnected (floating). Receivers easily meet the data rates supported by the corresponding driver. IL3000-Series receiver outputs have tri-state capabilities with active low RE inputs. Driver Features The RS485/422 driver is a differential output device that delivers at least 1.5 V across a 54 Ω load (RS-485), and at least 2 V across a 100 Ω load (RS-422). The driver features low propagation delay skew to maximize bit width and minimize EMI. IL3222 and IL3285 drivers have tri-state capability with an active high DE input. 8 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Cabling, Data Rate and Terminations Cabling Use twisted-pair cable. The cable can be unshielded if it is short (less than 10 meters) and the data rate is slow (less than 100 Kbps). Otherwise, use screened cable with the shield tied to earth ground at one end only. Do not tie the shield to digital ground. The other end of the shield may be tied to earth ground through an RC network. This prevents a DC ground loop in the shield. Shielded cable minimizes EMI emissions and external noise coupling to the bus. Data Rate The longer the cable, the slower the data rate. The RS-485 bus can transmit ground over 4,000 feet (1,200 meters) or at 10 Mbps, but not both at the same time. Transducer and cable characteristics combine to act as a filter with the general response shown in Figure 3. Other parameters such as acceptable jitter affect the final cable length versus data rate tradeoff. Less jitter means better signal quality but shorter cable lengths or slower data rates. Figure 4 shows a generally accepted 30% jitter and a corresponding data rate versus cable length. 4000 1000 Cable Length (feet) 100 40 100 1K 10K 100K Data Rate (bps) 1M 10M Figure 3. Cable Length vs. Data Rate (30% jitter). Terminations Transmission lines should be terminated to avoid reflections that cause data errors. In RS-485 systems both ends of the bus, not every node, should be terminated. In RS-422 systems only the receiver end should be terminated. 100 Ω Unterminated Parallel Proper termination is imperative when using IL3185 and IL3122 to minimize reflections. Unterminated lines are only suitable for very low data rates and very short cable runs, otherwise line reflections cause problems. Parallel terminations are the most popular. They allow high data rates and excellent signal quality. Occasionally in noisy environments, fast pulses or noise appearing on the bus lines cause errors. One way of alleviating such errors without adding circuit delays is to place a series resistor in the bus line. Depending on the power supply, the resistor should be between 300 Ω (3 V supply) and 500 Ω (5 V supply). 9 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Typical Coil Connections 16pF ±50% 16pF ±50% DE VDD1 D R1 DE VCOIL1 VDD1 16pF ±50% R2 16pF ±50% R VCOIL2 R3 D VDD2 R1 VCOIL1 Y Z 16pF ±50% R2 VCOIL2 16pF ±50% A B R RE R3 VDD2 A B RE VDD1 = VDD2 = 5 V R1, R2, R3 = 820 Ω VDD1 = 3.3 V R1, R2 = 510 Ω; R3 = 820 Ω VDD1 = VDD2 = 5 V R1, R2, R3 = 820 Ω R1, R2 = 510 Ω; R3 = 820 Ω VDD1 = 3.3 V Fail-Safe Operation “Fail-safe operation” is defined here as the forcing of a logic high state on the “R” output in response to an open-circuit condition between the “A” and “B” lines of the bus, or when no drivers are active on the bus. Proper biasing can ensure fail-safe operation, that is a known state when there are no active drivers on the bus. IL3185 and IL3122 Isolated Transceivers include internal pull-up and pull-down resistors of approximately 30 kΩ in the receiver section (RFS-INT; see figure on following page). These internal resistors are designed to ensure failsafe operation but only if there are no termination resistors. The entire VDD will appear between inputs “A” and “B” if there is no loading and no termination resistors, and there will be more than the required 200 mV with up to four RS-485/RS-422 worst-case Unit Loads of 12 kΩ. Many designs operating below 1 Mbps or less than 1,000 feet are unterminated. Termination resistors may not be necessary for very low data rates and very short cable runs because reflections have time to settle before data sampling, which occurs at the middle of the bit interval. In busses with low-impedance termination resistors, however, the differential voltage across the conductor pair will be close to zero with no active drivers. In this case the state of the bus is indeterminate, and the idle bus will be susceptible to noise. For example, with 120 Ω termination resistors (RT) on each end of the cable, and four Unit Loads (12 kΩ each), without external failsafe biasing resistors the internal pull-up and pull-down resistors will produce a voltage between inputs “A” and “B” of only about 5 mV. This is not nearly enough to ensure a known state. External fail-safe biasing resistors (RFS-EXT) at one end of the bus can ensure fail-safe operation with a terminated bus. Resistors should be selected so that under worst-case power supply and resistor tolerances there is at least 200 mV across the conductor pair with no active drivers to meet the input sensitivity specification of the RS-422 and RS-485 standards. Using the same value for pull-up and pull-down biasing resistors maintains balance for positive- and negative going transitions. Lower-value resistors increase inactive noise immunity at the expense of quiescent power consumption. Note that each Unit Load on the bus adds a worst-case loading of 12 kΩ across the conductor pair, and 32 Unit Loads add 375 Ω worst-case loading. The more loads on the bus, the lower the required values of the biasing resistors. In the example with two 120 Ω termination resistors and four Unit Loads, 560 Ω external biasing resistors provide more than 200 mV between “A” and “B” with adequate margin for power supply variations and resistor tolerances. This ensures a known state when there are no active drivers. Other illustrative examples are shown in the following table: 10 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Fail-Safe Biasing 5V RFS-EXT VDD 30K RFS-INT A RT None 120 Ω 120 Ω 120 Ω RFS-EXT 30K RFS-INT B GND RFS-EXT Internal Only Internal Only 560 Ω 510 Ω RT RT R Loading Four unit loads (12 kΩ ea.) Four unit loads (12 kΩ ea.) Four unit loads (12 kΩ ea.) 32 unit loads (12 kΩ ea.) Nominal VA-B Fail-Safe Operation? (inactive) 238 mV Yes 5 mV No 254 mV Yes 247 mV Yes Power Supply Decoupling Both VDD1 and VDD2 should be bypassed with 47 nF low-ESR ceramic capacitors. These should be placed as close as possible to VDD pins. VDD2 should also be bypassed with a 10 µF tantalum capacitor. Maintaining Creepage Creepage distances are often critical in isolated circuits. In addition to meeting JEDEC standards, NVE isolator packages have unique creepage specifications. Standard pad libraries often extend under the package, compromising creepage and clearance. Similarly, ground planes, if used, should be spaced to avoid compromising clearance. Package drawings and recommended pad layouts are included in this datasheet. Magnetic Field Immunity IsoLoop Isolators operate by imposing a magnetic field on a GMR sensor, which translates the change in field into a change in logic state. A magnetic shield and a Wheatstone Bridge configuration provide good immunity to external magnetic fields. Immunity to external magnetic fields can be enhanced by proper orientation of the device with respect to the field direction and larger boost capacitors. An applied field in the “H1” direction is the worst case for magnetic immunity. In this case the external field is in the same direction as the applied internal field. In one direction it will tend to help switching; in the other it will hinder switching. This can cause unpredictable operation. VDD1 VCOIL2 GND1 GND2 R RE DE NC H2 VCOIL1 D GND1 B H1 A VDD2 NC GND2 Figure 3. Orientation of External Magnetic Field An applied field in the direction of “H2” has considerably less effect on the sensor and will result in significantly higher immunity levels as shown in Table 1. The greatest magnetic immunity is achieved by adding a larger boost capacitor across the input resistor. Very high immunity can be achieved with this method. 11 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Method Approximate Immunity Field applied in direction H1 ±20 Gauss Field applied in direction H2 ±70 Gauss Field applied in any direction but with boost capacitor (470 pF) in circuit Table 1. Magnetic Immunity ±250 Gauss Immunity Description A DC current of 16 A flowing in a conductor 1 cm from the device could cause disturbance A DC current of 56 A flowing in a conductor 1 cm from the device could cause disturbance A DC current of 200 A flowing in a conductor 1 cm from the device could cause disturbance Data Rate and Magnetic Field Immunity It is easier to disrupt an isolated DC signal with an external magnetic field than it is to disrupt an isolated AC signal. Similarly, a DC magnetic field will have a greater effect on the device than an AC magnetic field of the same effective magnitude. For example, signals with pulses longer than 100 μs are more susceptible to magnetic fields than shorter pulse widths. For input signals faster than 1 MHz, rising in less than 3 ns, a 470 pF field-boost capacitor provides as much as 400 Gauss immunity, while the same input capacitor might provide just 70 Gauss immunity at 50 kHz. 12 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Package Drawings 0.15" 16-pin SOIC Package (-3 suffix) Dimensions in inches (mm); scale = approx. 5X 0.013 (0.3) 0.020 (0.5) NOM 0.007 (0.2) 0.013 (0.3) 0.386 (9.8) 0.394 (10.0) Pin 1 identified by either an indent or a marked dot 0.016 (0.4) 0.050 (1.3) 0.055 (1.40) 0.062 (1.58) 0.054 (1.4) 0.072 (1.8) 0.150 (3.81) 0.157 (3.99) 0.049 (1.24) 0.051 (1.30) 0.228 (5.8) 0.244 (6.2) NOTE: Pin spacing is a BASIC dimension; tolerances do not accumulate 0.004 (0.1) 0.012 (0.3) 0.3" 16-pin SOIC Package (no suffix) Dimensions in inches (mm); scale = approx. 5X 0.033 (0.85)* 0.043 (1.10) 0.260 (6.60)* 0.280 (7.11) 0.013 (0.3) 0.020 (0.5) 0.007 (0.2) 0.013 (0.3) 0.397 (10.08) 0.413 (10.49) 0.017 (0.43)* 0.022 (0.56) 0.016 (0.4) 0.050 (1.3) 0.007 (0.18)* 0.010 (0.25) 0.092 (2.34) 0.105 (2.67) Pin 1 identified by either an indent or a marked dot 0.08 (2.0) 0.10 (2.5) 0.292 (7.42)* 0.299 (7.59) 0.049 (1.24) 0.051 (1.30) 0.394 (10.00) 0.419 (10.64) NOTE: Pin spacing is a BASIC dimension; tolerances do not accumulate *Specified for True 8™ package to guarantee 8 mm creepage per IEC 60601. 0.004 (0.1) 0.012 (0.3) 13 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Recommended Pad Layouts 0.15" 16-pin SOIC Pad Layout Dimensions in inches (mm); scale = approx. 5X 0.160 (4.06) 0.050 (1.27) 0.020 (0.51) 16 PLCS 0.275 (6.99) 0.3" 16-pin SOIC Pad Layout Dimensions in inches (mm); scale = approx. 5X 0.317 (8.05) 0.050 (1.27) 0.020 (0.51) 16 PLCS 0.449 (11.40) 14 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Ordering Information and Valid Part Numbers IL 31 85 -3 E TR13 Valid Part Numbers Bulk Packaging Blank = Tube TR13 = 13'' Tape and Reel IL3185E IL3185E TR13 IL3185-3E IL3185-3E TR13 Package E = RoHS Compliant IL3122E IL3122E TR13 IL3122-3E IL3122-3E TR13 Package Type Blank = 0.3'' SOIC -3 = 0.15'' SOIC Channel Configuration 22 = RS-422 85 = RS-485 Base Part Number 31 = Passive-In, 5 Mbps Transceiver Product Family IL = Isolators RoHS COMPLIANT 15 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Revision History ISB-DS-001 IL3185/22-P November 2013 ISB-DS-001 IL3185/22-O ISB-DS-001 IL3185/22-N ISB-DS-001-IL3185/22-M ISB-DS-001-IL3185/22-L Changes • IEC 60747-5-5 (VDE 0884) certification. • Upgraded from MSL 2 to MSL 1. • Rearranged low level input current specification so maximum is more than minimum. Changes • Added VDE 0884 pending. • Clarified switching specifications. • Updated package drawings. • Added recommended solder pad layouts. Changes • Detailed isolation and barrier specifications. • Cosmetic changes. Changes • Added minimum/maximum coil resistance specifications. • Misc. cosmetic changes. Changes • ISB-DS-001-IL3185/22-K Changes • ISB-DS-001-IL3185/22-J ISB-DS-001-IL3185/22-I • Changes to current-limiting resistor values (pp. 7 and 10). • Details for boost capacitor selection (p. 7). Changes ISB-DS-001-IL3185/22-F Added bus-protection ESD specification (15 kV). Changes • Added typical coil resistance and temperature coefficient specifications. • Added note on package drawings that pin-spacing tolerances are non-accumulating. Changes • ISB-DS-001-IL3185/22-E Noted UL1577 approval. Changes • ISB-DS-001-IL3185/22-G Clarified ground pin connections (pp. 3-4). Changes • ISB-DS-001-IL3185/22-H Update terms and conditions. Changed ordering information to reflect that devices are now fully RoHS compliant with no exemptions. Changes • Eliminated soldering profile chart 16 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 Datasheet Limitations The information and data provided in datasheets shall define the specification of the product as agreed between NVE and its customer, unless NVE and customer have explicitly agreed otherwise in writing. All specifications are based on NVE test protocols. In no event however, shall an agreement be valid in which the NVE product is deemed to offer functions and qualities beyond those described in the datasheet. Limited Warranty and Liability Information in this document is believed to be accurate and reliable. However, NVE does not give any representations or warranties, expressed or implied, as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information. In no event shall NVE be liable for any indirect, incidental, punitive, special or consequential damages (including, without limitation, lost profits, lost savings, business interruption, costs related to the removal or replacement of any products or rework charges) whether or not such damages are based on tort (including negligence), warranty, breach of contract or any other legal theory. Right to Make Changes NVE reserves the right to make changes to information published in this document including, without limitation, specifications and product descriptions at any time and without notice. This document supersedes and replaces all information supplied prior to its publication. Use in Life-Critical or Safety-Critical Applications Unless NVE and a customer explicitly agree otherwise in writing, NVE products are not designed, authorized or warranted to be suitable for use in life support, life-critical or safety-critical devices or equipment. NVE accepts no liability for inclusion or use of NVE products in such applications and such inclusion or use is at the customer’s own risk. Should the customer use NVE products for such application whether authorized by NVE or not, the customer shall indemnify and hold NVE harmless against all claims and damages. Applications Applications described in this datasheet are illustrative only. NVE makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Customers are responsible for the design and operation of their applications and products using NVE products, and NVE accepts no liability for any assistance with applications or customer product design. It is customer’s sole responsibility to determine whether the NVE product is suitable and fit for the customer’s applications and products planned, as well as for the planned application and use of customer’s third party customers. Customers should provide appropriate design and operating safeguards to minimize the risks associated with their applications and products. NVE does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the customer’s applications or products, or the application or use by customer’s third party customers. The customer is responsible for all necessary testing for the customer’s applications and products using NVE products in order to avoid a default of the applications and the products or of the application or use by customer’s third party customers. NVE accepts no liability in this respect. Limiting Values Stress above one or more limiting values (as defined in the Absolute Maximum Ratings System of IEC 60134) will cause permanent damage to the device. Limiting values are stress ratings only and operation of the device at these or any other conditions above those given in the recommended operating conditions of the datasheet is not warranted. Constant or repeated exposure to limiting values will permanently and irreversibly affect the quality and reliability of the device. Terms and Conditions of Sale In case an individual agreement is concluded only the terms and conditions of the respective agreement shall apply. NVE hereby expressly objects to applying the customer’s general terms and conditions with regard to the purchase of NVE products by customer. No Offer to Sell or License Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other industrial or intellectual property rights. Export Control This document as well as the items described herein may be subject to export control regulations. Export might require a prior authorization from national authorities. Automotive Qualified Products Unless the datasheet expressly states that a specific NVE product is automotive qualified, the product is not suitable for automotive use. It is neither qualified nor tested in accordance with automotive testing or application requirements. NVE accepts no liability for inclusion or use of non-automotive qualified products in automotive equipment or applications. In the event that customer uses the product for design-in and use in automotive applications to automotive specifications and standards, customer (a) shall use the product without NVE’s warranty of the product for such automotive applications, use and specifications, and (b) whenever customer uses the product for automotive applications beyond NVE’s specifications such use shall be solely at customer’s own risk, and (c) customer fully indemnifies NVE for any liability, damages or failed product claims resulting from customer design and use of the product for automotive applications beyond NVE’s standard warranty and NVE’s product specifications. 17 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation IL3185/IL3122 An ISO 9001 Certified Company NVE Corporation 11409 Valley View Road Eden Prairie, MN 55344-3617 USA Telephone: (952) 829-9217 Fax: (952) 829-9189 www.nve.com e-mail: [email protected] ©NVE Corporation All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. ISB-DS-001-IL3185/22-P November 2013 18 NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 Phone: (952) 829-9217 Fax: (952) 829-9189 www.IsoLoop.com ©NVE Corporation