LTM2885

LTM2885 (Rev. B)

Document overview

• Manufacturer or author: Analog Devices Inc.
• PDF pages: 22

Technical content

Rev. BFor more information www.analog.comDocument Feedback TYPICAL APPLICATION

DESCRIPTION

RS485/RS422 µModule Transceiver + Power The LT M®2885 is a complete galvanically isolated full-duplex RS485/RS422 µModule ® ( micromodule) transceiver. No external components are required. A single supply powers both sides of the interface through an integrated, isolated, low noise, efficient 5 V output DC/DC converter. Coupled inductors and an isolation power transformer provide 6500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems where the ground loop is broken allowing for large common mode voltage variation. Uninterrupted communication is guaranteed for common mode transients up to 50kV/μs. Maximum data rates are 20Mbps or 250kbps in slew limited mode. T ransmit data, DI, and receive data, RO, are implemented with event driven low jitter processing. The receiver has a one-eighth unit load supporting up to 256 nodes per bus. A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply. Enhanced ESD protection allows this part to withstand up to ±15kV (human body model) on the transceiver interface pins to isolated supplies and ±25kV through the isolation barrier to logic supplies without latch-up or damage. Isolated Half-Duplex RS485 μModule Transceiver

FEATURES

APPLICATIONS

n RS485/RS422 T ransceiver: 6500VRMS for 1 Minute n CSA (IEC/UL) Approved, File #255632 n Isolated DC Power: 5V at 200mA n No External Components Required n 20Mbps or Low EMI 250kbps Data Rate n High ESD: ±15kV HBM on T ransceiver Interface n High Common Mode T ransient Immunity: 50kV/μs n Integrated Selectable 120Ω Termination n Extended Creepage and Clearance ~14.6mm n 1.62V to 5.5V Logic Supply Pin for Flexible Digital Interface n Maximum Continuous Working Voltage: 690VRMS n High Input Impedance Failsafe RS485 Receiver n Current Limited Drivers and Thermal Shutdown n Compatible with TIA/EIA-485-A and PROFIBUS n High Impedance Output During Internal Fault Condition n Low Current Shutdown Mode (< 10µA) n General Purpose CMOS Isolated Channel n 22mm × 9mm × 5.16mm Surface Mount BGA Package n Isolated RS485/RS422 Interface n Industrial Networks n Breaking RS485 Ground Loops n Isolated PROFIBUS-DP Networks

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A VCC2 5V OUT RO VL TE RE DE DI GND GND2 VCC L TM2885 B Y Z PWR ISOLATION BARRIER LTM2885 Operating Through 100kV/μs CM Transients All registered trademarks and trademarks are the property of their respective owners.

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Rev. B For more information www.analog.com PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS Interface Voltages Signal Voltages ON, RO, DI, DE, (Note 1) ORDER INFORMATION Signal Voltages SLO, Operating Temperature Range (Note 4) ON V L RO RE DE DI TE V CC DOUT NC NC DIN SLO GND2 Y Z B A V CC2 A B P R S T C D E F G H J K L M N GND BGA PACKAGE 42-PIN (22mm × 9mm × 5.2mm) TJMAX = 125°C, θJA = 35°C/W , θJC(BOTTOM) = 23.9°C/W , θJC(TOP) = 29.6°C/W , θJBOARD = 22.7°C/W θ VALUES DETERMINED PER JESD51-9, WEIGHT = 1.9g TOP VIEW PART NUMBER PAD OR BALL FINISH PART MARKING PACKAGE TYPE MSL RATING TEMPERATURE RANGEDEVICE FINISH CODE LTM2885CY#PBF SAC305 (RoHS) LTM2885Y e1 42-BGA 3 0°C to 70°C LTM2885IY#PBF –40°C to 85°C LTM2885HY#PBF –40°C to 105°C

• Contact the factory for parts specified with wider operating temperature ranges. *Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Recommended LGA and BGA PCB Assembly and Manufacturing Procedures
• LGA and BGA Package and Tray Drawings

Rev. BFor more information www.analog.com

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply VCC VCC Supply Voltage l 4.5 5.0 5.5 V VL VL Supply Voltage l 1.62 5.5 V ICCPOFF VCC Supply Current in Off Mode ON = 0V l 0 10 µA ICCS VCC Supply Current in On Mode DE = 0V, RE = VL, No Load l 38 50 mA VCC2 Regulated VCC2 Output Voltage, Loaded DE = 0V, RE = VL, ILOAD = 150mA l 4.75 5.0 V VCC2NOLOAD Regulated VCC2 Output Voltage, No Load DE = 0V, RE = VL, No Load 4.8 5.0 5.35 V Efficiency ICC2 = 100mA (Note 2) 50 % ICC2S VCC2 Short-Circuit Current DE = 0V, RE = VL, VCC2 = 0V 200 mA Driver |VOD| Differential Driver Output Voltage R = ∞ (Figure 1) R = 27Ω (RS485) (Figure 1) R = 50Ω (RS422) (Figure 1) l l l 2.1 2.1 VCC2 VCC2 VCC2 V V V ∆|VOD| Difference in Magnitude of Driver Differential Output Voltage for Complementary Output States R = 27Ω or R = 50Ω (Figure 1) l 0.2 V VOC Driver Common Mode Output Voltage R = 27Ω or R = 50Ω (Figure 1) l 3 V ∆|VOC| Difference in Magnitude of Driver Common Mode Output Voltage for Complementary Output States R = 27Ω or R = 50Ω (Figure 1) l 0.2 V IOZD Driver Three-State (High Impedance) Output Current on Y and Z DE = 0V, (Y or Z) = –7V, +12V DE = 0V, (Y or Z) = –7V, +12V, H-Grade l l ±10 ±50 µA µA IOSD Maximum Driver Short-Circuit Current –7V ≤ (Y or Z) ≤ 12V (Figure 2) l – 250 250 mA Receiver RIN Receiver Input Resistance RE = 0V or VL, VIN = –7V, –3V, 3V, 7V, 12V (Figure 3) RE = 0V or VL, VIN = –7V, –3V, 3V, 7V, 12V (Figure 3), H-Grade l l 125 125 kΩ kΩ RTE Receiver Termination Resistance Enabled TE = VL, VAB = 2V, VB = –7V, 0V, 10V (Figure 8) l 105 120 156 Ω IIN Receiver Input Current (A, B) ON = 0V VCC2 = 0V or 5V, VIN = 12V (Figure 3) ON = 0V VCC2 = 0V or 5V, VIN = 12V (Figure 3), H-Grade l l 125 250 µA µA ON = 0V VCC2 = 0V or 5V, VIN = –7V (Figure 3) ON = 0V VCC2 = 0V or 5V, VIN = –7V (Figure 3), H-Grade l l –100 –145 µA µA VTH Receiver Differential Input Threshold Voltage (A-B) –7V ≤ B ≤ 12V l –0.2 0.2 V ∆VTH Receiver Input Failsafe Hysteresis B = 0V 25 mV Receiver Input Failsafe Threshold B = 0V –0.2 –0.05 0 V The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5.0V, VL = 3.3V, GND = GND2 = 0V, ON = VL unless otherwise noted.

Rev. B For more information www.analog.com SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Logic VIL Logic Input Low Voltage 1.62V ≤ VL ≤ 5.5V l 0.4 V VIH Logic Input High Voltage DIN SLO DI, TE, DE, ON, RE: VL ≥ 2.35V 1.62V ≤ VL < 2.35V l l l l 0.67•VCC2 0.67•VL 0.75•VL V V V V IINL Logic Input Current l 0 ±1 µA VHYS Logic Input Hysteresis (Note 2) 150 mV VOH Output High Voltage Output High, ILOAD = –4mA (Sourcing), 5.5V ≥ VL ≥ 3V Output High, ILOAD = –1mA (Sourcing), 1.62V ≤ VL < 3V l l VL –0.4 VL –0.4 V V VOL Output Low Voltage Output Low, ILOAD = 4mA (Sinking), 5.5V ≥ VL ≥ 3V Output High, ILOAD = 1mA (Sinking), 1.62V ≤ VL < 3V l l 0.4 0.4 V V IOZR Three-State (High Impedance) Output Current on RO RE = VL, 0V ≤ RO ≤ VL l ±1 µA IOSR Short-Circuit Current 0V ≤ (RO or DOUT) ≤ VL l ±85 mA ESD (HBM) (Note 2) RS485 Driver and Receiver Protection (Y, Z, A, B) to (GND, GND2) ±15 kV Isolation Boundary (VCC2, GND2) to (VCC, VL, GND) ±25 kV ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5.0V, VL = 3.3V, GND = GND2 = 0V, ON = VL unless otherwise noted.

Rev. BFor more information www.analog.com SWITCHING CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5.0V, VL = 3.3V, GND = GND2 = 0V, ON = VL unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Driver SLO = VCC2 fMAX Maximum Data Rate (Note 3) 20 Mbps tPLHD tPHLD Driver Input to Output RDIFF = 54Ω, CL = 100pF (Figure 4) l 60 85 ns ∆tPD Driver Input to Output Difference |tPLHD – tPHLD| RDIFF = 54Ω, CL = 100pF (Figure 4) l 1 8 ns tSKEWD Driver Output Y to Output Z RDIFF = 54Ω, CL = 100pF (Figure 4) l 1 ±8 ns tRD tFD Driver Rise or Fall Time RDIFF = 54Ω, CL = 100pF (Figure 4) l 4 12.5 ns tZLD, tZHD, tLZD, tHZD Driver Output Enable or Disable Time RL = 500Ω, CL = 50pF (Figure 5) l 170 ns Driver SLO = GND2 fMAX Maximum Data Rate (Note 3) 250 kbps tPLHD tPHLD Driver Input to Output RDIFF = 54Ω, CL = 100pF (Figure 4) 1 1.55 µs ∆tPD Driver Input to Output Difference |tPLHD – tPHLD| RDIFF = 54Ω, CL = 100pF (Figure 4) 50 500 ns tSKEWD Driver Output Y to Output Z RDIFF = 54Ω, CL = 100pF (Figure 4) ±200 ±750 ns tRD tFD Driver Rise or Fall Time RDIFF = 54Ω, CL = 100pF (Figure 4) l 0.9 1.5 µs tZLD, tZHD, tLZD, tHZD Driver Output Enable or Disable Time RL = 500Ω, CL = 50pF (Figure 5) l 400 ns Receiver tPLHR tPHLR Receiver Input to Output CL = 15pF, VCM = 2.5V, |VAB| = 1.4V, tR and tF < 4ns, (Figure 6) l 100 140 ns tSKEWR Differential Receiver Skew |tPLHR – tPHLR| CL = 15pF (Figure 6) l 1 8 ns tRR tFR Receiver Output Rise or Fall Time CL = 15pF (Figure 6) l 3 12.5 ns tZLR, tZHR, tLZR, tHZR Receiver Output Enable or Disable Time RL =1kΩ, CL = 15pF (Figure 7) l 50 ns tRTEN, tRTZ Termination Enable or Disable Time RE = 0V, DE = 0V, VAB = 2V, VB = 0V (Figure 8) l 100 µs Generic Logic Input tPLHL1 tPHLL1 DIN to DOUT Input to Output CL = 15pF, tR and tF < 4ns l 60 100 ns Power Supply Generator VCC2 – GND2 Supply Start-Up Time (0V to 4.5V) ON VL, No Load l 200 500 µs

Rev. B For more information www.analog.com ISOLATION CHARACTERISTICS TA = 25°C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VISO Rated Dielectric Insulation Voltage 1 Minute (Derived from 1 Second Test) 6500 VRMS

1 Second (Notes 5, 6, 7) 7800 VRMS

Common Mode T ransient Immunity VCC = 5V, VL = ON = 3.3V, ∆VCM = 1kV, ∆T = 20ns (Note 2) 50 kV/µs VIORM Maximum Working Insulation Voltage (Note 2) 1000 690 VPEAK, VDC VRMS Partial Discharge VPR = 1300VRMS (Notes 2, 5) 5 pC CTI Comparative T racking Index IEC 60112 (Note 2) 600 VRMS Depth of Erosion IEC 60112 (Note 2) 0.017 mm DTI Distance Through Insulation (Note 2) 0.2 mm Input to Output Resistance (Notes 2, 5) 1 5 TΩ Input to Output Capacitance (Notes 2, 5) 6 pF Creepage Distance (Notes 2, 5) 14.6 mm Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Guaranteed by design and not subject to production test. Note 3: Maximum Data rate is guaranteed by other measured parameters and is not tested directly. Note 4: This µModule transceiver includes over temperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when over temperature protection is active. Continuous operation above specified maximum operating junction temperature may result in device degradation or failure. Note 5: Device considered a 2-terminal device. Pin group A1 through C7 shorted together and pin group R1 through T7 shorted together. Note 6: The rated dielectric insulation voltage should not be interpreted as a continuous voltage rating. Note 7: In accordance with UL1577, each device is proof tested for the 1 minute RMS rating by applying the equivalent RMS voltage multiplied by an acceleration factor of 1.2 for one second. Note 8: Ratings are for pollution degree 2, material group 3 and overvoltage category II where applicable. Ratings for other environmental and electrical conditions to be determined from the appropriate safety standard. REGULATORY INFORMATION CSA (Note 8) CSA 60950-1-07+A1+A2 and IEC 60950-1, second edition, +A1 +A2: Basic Insulation at 1440VRMS Reinforced Insulation at 720VRMS CSA 62368-1-14 and IEC 62368-1-14:2014, second edition: Basic Insulation at 600VRMS Reinforced Insulation at 300VRMS CSA 60601-1:14 and IEC 60601-1, third edition, +A1: Tw o means of patient protection (2 MOPP) at 250VRMS UL 1577-2015: Single Protection, 6500VRMS Isolation Voltage File 255632

Rev. BFor more information www.analog.com TEMPERATURE (°C) RECEIVER SKEW (ns) 2.0 0.5 1.5 1.0 –0.5 –1.0

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1251007550250–25–50 Receiver Skew vs Temperature Driver Skew vs Temperature Driver Propagation Delay vs Temperature TEMPERATURE (°C) DRIVER SKEW (ns) 2.0 0.5 1.5 1.0 –0.5 –1.0

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1251007550250–25–50 TEMPERATURE (°C) DRIVER PROP DELAY (ns)

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1251007550250–25–50 TYPICAL PERFORMANCE CHARACTERISTICS Receiver Output Voltage vs Output Current (Source and Sink) Receiver Propagation Delay vs Temperature RTERM vs Temperature Driver Output Low/High Voltage vs Output Current Driver Differential Output Voltage vs Temperature TEMPERATURE (°C) RESISTANCE (/uni03A9) 130 110 112 114 116 118 120 122 124 126 128

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1251007550250–25–50 OUTPUT CURRENT (mA) OUTPUT VOL TAGE (V) 5.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

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TEMPERATURE (°C) OUTPUT VOL TAGE (V)

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1251007550250–25–50 R = ∞ R = 100/uni03A9 R = 54/uni03A9 TA = 25°C, VCC = 5.0V, VL = 3.3V unless otherwise noted. OUTPUT CURRENT (mA) OUTPUT VOL TAGE (V)

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TEMPERATURE (°C) RECEIVER PROP DELAY (ns) 120 115 110 105 100

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1251007550250–25–50 DATA RATE (Mbps) 0.1 100 110 120 130 140 150 SUPPL Y CURRENT (mA) Supply Current vs Data Rate

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R = 100Ω R = 54Ω

Rev. B For more information www.analog.com TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, VCC = 5.0V, VL = 3.3V unless otherwise noted. VCC Supply Current vs Temperature at ILOAD = 100mA on VCC2 VCC2 200mV/DIV ILOAD 50mA/DIV

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100µs/DIV 10mV/DIV

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200µs/DIV VCC2 Load Step (100mA) VCC2 Noise TEMPERATURE (°C) –50 –25 100 125 100 125 150 175 200 225 250 275 300 I CC2 CURRENT (mA) vs Temperature Available V CC2 Current

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R 485 = OPEN, C 485 = 0pF , 0Mbps, V CM = 0V R 485 = 54Ω, C 485 = 500pF , 10Mbps, V CM = –7V V CC = 5.0V , V CC2 ≥ 4.75V LOAD CURRENT (mA) 100 150 200 250 4.0 4.1 4.2 4.3 4.4 4.6 4.7 4.8 4.9 5.0 5.1 VOL TAGE (V) V CC2 vs Load Current

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V CC = 4.5V V CC = 5.0V V CC = 5.5V LOAD CURRENT (mA) 100 150 200 250 0.0 0.4 0.8 1.2 1.6 2.0 2.4 EFFICIENCY (%) POWER LOSS (W) vs Load Current V CC2 Efficiency and Power Loss

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V CC = 4.5V V CC = 5.0V V CC = 5.5V EFFICIENCY POWER LOSS RS485 ENABLED AND TERMINATED NO LOAD V CC = 4.5V V CC = 5.0V V CC = 5.5V TEMPERATURE (°C) –50 –25 100 125 100 I CC CURRENT (mA) vs Temperature

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Rev. BFor more information www.analog.com LOGIC SIDE TE (Pin A1): Terminator Enable. A logic high enables a termination resistor (typically 120Ω) between pins A and B. Do not float. DI (Pin A2): Driver Input. If the driver outputs are enabled (DE high), then a low on DI forces the driver noninverting output (Y) low and the inverting output (Z) high. A high on DI, with the driver outputs enabled, forces the driver noninverting output (Y) high and inverting output (Z) low. Do not float. DE (Pin A3): Driver Enable. A logic low disables the driver leaving the outputs Y and Z in a high impedance state. A logic high enables the driver. Do not float. RE (Pin A4): Receiver Enable. A logic low enables the receiver output. A logic high disables RO to a high imped- ance state. Do not float. RO (Pin A5): Receiver Output. If the receiver output is ena bled (RE low) and if A – B is > 200mV, RO is a logic high, if A – B is < 200mV RO is a logic low. If the receiver inputs are open, shorted, or terminated without a valid signal for more than approximately 3μs, RO is a logic high. Under the condition of an isolation communication failure RO is in a high impedance state. VL (Pin A6): Logic Supply. Interface supply voltage for pins RO, RE, TE, DI, DE, DOUT, and ON. Recommended operating voltage is 1.62V to 5.5V. Internally bypassed to GND with 2.2µF. ON (Pin A7): Enable. Enables power and data communica- tion through the isolation barrier. If ON is high the part is enabled and power and communications are functional to the isolated side. If ON is low the logic side is held in reset and the isolated side is unpowered. Do not float. DOUT (Pin B1): General Purpose Logic Output. Logic output connected through isolation path to DIN. Under the condition of an isolation communication failure DOUT is in a high impedance state. PIN FUNCTIONS GND (Pins B2-B5): Circuit Ground. VCC (Pins B6-B7): Supply Voltage. Recommended operat- ing voltage is 4.5V to 5.5V. Internally bypassed to GND with 2.2µF. NC ( Pins C1-C7): No Connect. Pins with no internal connection. ISOLATED SIDE NC (Pins R1-R7): No Connect. Pins with no internal connection. DIN (Pin S1): General Purpose Isolated Logic Input. Logic input on the isolated side relative to VCC2 and GND2. A logic high on DIN will generate a logic high on DOUT. A logic low on DIN will generate a logic low on DOUT. Do not float. GND2 (Pins S2-S7): Isolated Side Circuit Ground. The pads should be connected to the isolated ground and/or cable shield. SLO (Pin T1): Driver Slew Rate Control. A low input, rela- tive to GND2, will force the driver into a reduced slew rate mode for reduced EMI. A high input, relative to GND2, puts the driver into full speed mode to support maximum data rates. Do not float. Y (Pin T2): Noninverting Driver Output. High impedance when the driver is disabled. Z (Pin T3): Inverting Driver Output. High impedance when the driver is disabled. B (Pin T4): Inverting Receiver Input. Impedance is > 96kΩ in all modes, powered and unpowered. A (Pin T5): Noninverting Receiver Input. Impedance is > 96kΩ in all modes, powered and unpowered. VCC2 (Pins T6-T7): Isolated Supply Voltage. Internally generated from VCC by an isolated DC/DC converter and regulated to 5V. Internally bypassed to GND2 with 2.2µF.

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Figure 1. Driver DC Characteristics Figure 2. Driver Output Short-Circuit Current Figure 3. Receiver Input Current and Input Resistance

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Figure 4. Driver Timing Measurement Receiver

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Figure 5. Driver Enable and Disable Timing Measurements

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Figure 6. Propagation Delay Measurements

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Figure 7. Receiver Enable/Disable Time Measurements

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Figure 8. Termination Resistance and Timing Measurements

0 X X X Off RIN Hi-Z Off Off

Rev. BFor more information www.analog.com Overview The LTM2885 µModule transceiver provides a galvanically- isolated robust RS485/RS422 interface, powered by an integrated, regulated DC/DC converter, complete with decoupling capacitors. A switchable termination resistor is integrated at the receiver input to provide proper termi- nation to the RS485 bus. The LTM2885 is ideal for use in networks where grounds can take on different voltages. Isolation in the LTM2885 blocks high voltage differences and eliminates ground loops and is extremely tolerant of common mode transients between ground potentials. Error free operation is maintained through common mode events greater than 50kV/μs providing excellent noise isolation. µModule Technology The LTM2885 utilizes isolator µModule technology to translate signals and power across an isolation barrier. Signals on either side of the barrier are encoded into pulses and translated across the isolation boundary using coreless transformers formed in the µModule substrate. This system, complete with data refresh, error checking, safe shutdown on fail, and extremely high common mode immunity, provides a robust solution for bidirectional signal isolation. The µModule technology provides the means to combine the isolated signaling with our RS485 transceiver and powerful isolated DC/DC converter in one small package. DC/DC Converter The LTM2885 contains a fully integrated isolated DC/DC converter, including the transformer, so that no external components are necessary. The logic side contains a full- bridge driver, running about 2MHz, and is AC-coupled to a single transformer primary. A series DC blocking capacitor prevents transformer saturation due to driver duty cycle imbalance. The transformer scales the primary voltage, which is then rectified by a voltage doubler. This topology eliminates transformer saturation caused by secondary imbalances. The DC/DC converter is connected to a low dropout reg- ulator (LDO) to provide a regulated low noise 5V output. The internal power solution is sufficient to support the transceiver interface at its maximum specified load and APPLICATIONS INFORMATION data rate. The logic supplies, VCC and VL have a 2.2µF decoupling capacitance to GND and the isolated supply VCC2 has a 2.2µF decoupling capacitance to GND2 within the µModule package. VCC2 Output The on-board DC/DC converter provides isolated 5V power to output VCC2. VCC2 is capable of suppling up to 1W of power at 5V. This surplus current is available to external applications. The amount of surplus current is dependent upon the implementation and current delivered to the RS485 driver and line load. An example of available surplus current is shown in the Typical Performance Characteristics graph, VCC2 Surplus Current vs Temperature. Figure 21 demonstrates a method of using the VCC2 output directly and with a switched power path that is controlled with the isolated RS485 data channel. Driver The driver provides full RS485 and RS422 compatibility. When enabled, if DI is high, Y–Z is positive. When the driver is disabled, both outputs are high impedance with less than 10µA of leakage current over the entire common mode range of –7V to 12V, with respect to GND2. Driver Overvoltage and Overcurrent Protection The driver outputs are protected from short circuits to any voltage within the absolute maximum range of (VCC2 –15V) to (GND2 +15V) levels. The maximum VCC2 cur- rent in this condition is 250mA. If the pin voltage exceeds about ±10V, current limit folds back to about half of the peak value to reduce overall power dissipation and avoid damaging the part. The device also features thermal shutdown protection that disables the driver and receiver output in case of excessive power dissipation (see Note 4 in the Electrical Characteristics section). SLO Mode The LTM2885 features a logic- selectable reduced slew rate mode ( SLO mode) that softens the driver output edges to reduce EMI emissions from equipment and data cables. The reduced slew rate mode is entered by

caused by stubs or mismatched cables. state of the input with symmetric thresholds around 0V. the common mode transient rejection of the LTM2885.

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of less than ±1µA for voltages within the supply range. A and B is shown in Figure 10. Figure 10. Equivalent Input Resistance into A and B

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impedance, reflections will distort the signal waveforms. mance when configuring transceiver networks. abled and the differential resistance from A to B is 120Ω. and B with the termination resistor enabled and disabled. mon mode range of –7V to 12V as shown in Figure 12.

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Figure 11. Curve T race Between A and B with Termination Figure 12. Termination Resistance vs Common Mode Voltage Figure 13. Termination Magnitude and Phase vs Frequency Figure 14. Supply Current vs Data Rate and phase of the termination impedance versus frequency.

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driven, the receiver’s output is high. maintain the specified driver output swing.

• Input and output decoupling is not required, since these components are integrated within the package. An ad- ditional bulk capacitor with a value of 6.8µF to 22µF is recommended. The high ESR of this capacitor reduces board resonances and minimizes voltage spikes caused by hot plugging of the supply voltage. For EMI sensitive applications, an additional low ESL ceramic capacitor of 1µF to 4.7µF, placed as close to the power and ground terminals as possible, is recommended. Alternatively, a number of smaller value parallel capacitors may be used to reduce ESL and achieve the same net capacitance.
• Do not place copper on the PCB between the inner col- umns of pads. This area must remain open to withstand the rated isolation voltage.
• The use of solid ground planes for GND and GND2 is recommended for non-EMI critical applications to optimize signal fidelity, thermal performance, and to minimize RF emissions due to uncoupled PCB trace conduction. The drawback of using ground planes, where EMI is of concern, is the creation of a dipole antenna structure which can radiate differential voltages formed between GND and GND2. If ground planes are used it is recommended to minimize their area, and use contiguous planes as any openings or splits can exacerbate RF emissions.
• For large ground planes a small capacitance (≤330pF) from GND to GND2, either discrete or embedded within the substrate, provides a low impedance current return path for the module parasitic capacitance, minimizing any high frequency differential voltages and substantially reducing radiated emissions. Discrete capacitance will not be as effective due to parasitic ESL. In addition, volt- age rating, leakage, and clearance must be considered for component selection. Embedding the capacitance within the PCB substrate provides a near ideal capacitor and eliminates component selection issues; however, the PCB must be 4 layers. Care must be exercised in applying either technique to insure the voltage rating of the barrier is not compromised. APPLICATIONS INFORMATION

Figure 15. PROFIBUS-DP Connections with Termination layout considerations are necessary.

• Under heavily loaded conditions VCC and GND current can exceed 300mA. Sufficient copper must be used on the PCB to insure resistive losses do not cause the supply voltage to drop below the minimum allowed level. Similarly, the VCC2 and GND2 conductors must be sized to support any external load current. These heavy copper traces will also help to reduce thermal stress and improve the thermal conductivity. A 390/uni03A9 220/uni03A9 390/uni03A9 SHIELD PROFIBUS CABLE TYPE A VL DE RO DI GND VCC VCC2

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in T ransverse Electromagnetic Waveguides”. Figure 17. LTM2885 Demo Circuit 1794A Emissions signed per the data sheet PCB layout recommendations. Specific limits per test are detailed in Table 1. Figure 18. Cable Length vs Data Rate 20Mbps shows the maximum data rate when SLO is high.

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Figure 21. Switched 5V Power with Isolated CMOS Logic Connection with Low Voltage Interface Figure 22. 4-Wire Full-Duplex Self Biasing for Unshielded CAT5 Connection Figure 20. Full-Duplex RS485 ConnectionFigure 19. Isolated System Fault Detection

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2885 F21

2885 F22

Rev. B For more information www.analog.com PACKAGE DESCRIPTION PACKAGE TOP VIEW PIN “A1” CORNER Y X aaa Z aaa Z 42-Lead (22mm × 9mm × 5.16mm) (Reference LTC DWG# 05-08-1960 Rev A) NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS BALL DESIGNATION PER JESD MS-028 AND JEP95 DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE DETAIL A Øb (42 PLACES) DETAIL B SUBSTRATE A ccc Z DETAIL B PACKAGE SIDE VIEW MOLD CAP Z M X YZddd M Zeee SYMBOL A b D E e F G aaa bbb ccc ddd eee MIN 4.91 0.50 4.41 0.60 0.60 0.46 3.95 NOM 5.16 0.60 4.56 0.75 0.63 22.0 9.0 1.27 20.32 7.62 0.56 4.00 MAX 5.41 0.70 4.71 0.90 0.66 0.66 4.05 0.15 0.10 0.15 0.15 0.08 NOTES DIMENSIONS TOTAL NUMBER OF BALLS: 42 D E SUGGESTED PCB LAYOUT TOP VIEW 0.00 8.89 10.16 7.62 2.54 1.27 2.54 3.81 3.81 1.27 0.00 10.16 8.89 7.62 9.84 10.48 // bbb Z Z 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. SOLDER BALL COMPOSITION IS 96.5% Sn/3.0% Ag/0.5% Cu 0.63 ±0.025 Ø 42x 4.13 3.49 BGA 42 0314 REV A TRAY PIN 1 BEVEL PACKAGE IN TRAY LOADING ORIENTATION COMPONENT PIN “A1” L TMXXXXXX µModule

7 PACKAGE ROW AND COLUMN LABELING MAY VARY

AMONG µModule PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULL Y PACKAGE BOTTOM VIEW T S R P N M L K J H G F E D C B A 1234567 DETAIL A SEE NOTES PIN 1 e e F G b SEE NOTES b

Rev. BFor more information www.analog.com

REVISION HISTORY

REV DATE DESCRIPTION PAGE NUMBER A 04/17 Added Receiver Output Disable Time. 5 B 03/22 Added CSA (UL/IEC) Certifications. 1, 6 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Rev. B For more information www.analog.com  ANALOG DEVICES, INC. 2016-2022 www.analog.com RELATED PARTS TYPICAL APPLICATION PART NUMBER DESCRIPTION COMMENTS LTM2881 Isolated RS485/RS422 µModule T ransceiver with Power 20Mbps, ±15kV ESD, 2500VRMS Isolation with Power LTM2882 Dual Isolated RS232 µModule T ransceiver with Power 1Mbps, ±10kV ESD, 2500VRMS Isolation with Power LTM2883 SPI/Digital or I2C µModule Isolator with Power 2500VRMS Isolation with Adjustable ±12.5V and 5V Power in BGA Package LTM2884 Isolated USB T ransceiver with Power 2500VRMS, Auto Speed Selection, 1W to 2.5W Isolated Power LTM2886 SPI or I2C μModule Isolator with Adjustable 5V and ±5V Regulated Power 2500VRMS Isolation in Surface Mount BGA LTM2889 Complete 4Mbps CAN FD μModule Isolator + Power 2500VRMS Isolation in Surface Mount BGA LTM2892 SPI/Digital or I2C Isolated μModule 3500VRMS Isolation without Power in 9mm × 6.25mm BGA Package LTM2893 Complete 100MHz SPI ADC μModule Isolator 6000VRMS Isolation in Surface Mount BGA LTM2894 Complete Isolated USB μModule T ransceiver 7500VRMS Isolation in Surface Mount BGA LT C

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2885 TA02

B Y Z A PWR GND2 A VL RE DE TE RO DI GND VCC VCCC B Y Z PWR GND2 AVL RE DE TE RO DI GND VCC VCCB B Y Z PWR GND2 L TM2885 L TM2885L TM2885 VCC2 C B CABLE SHIELD OR GROUND RETURN ISOLATION BARRIER ISOLATION BARRIER ISOLATION BARRIER B Multi-Node Network with End Termination and Single Ground Connection on Isolation Bus