LTM2884 Isolated USB Transceiver with Isolated Power Features n n n n n n n n n n n Description Isolated USB Transceiver: 2500VRMS for 1 Minute UL-CSA Recognized File #E151738 USB 2.0 Full Speed and Low Speed Compatible Integrated Isolated DC/DC Converter, External or Bus Powered Auto-Configuration of Bus Speed 2.5W (500mA at 5V) Output Power from External Input Supply (VCC = 8.6V to 16.5V) 1W (200mA at 5V) Output Power from USB Bus Supply (VBUS) 3.3V LDO Output Supply Signal References VLO, VLO2 High Common Mode Transient Immunity: 30kV/s ESD: 15kV HBM on USB Interface Pins 15mm x 15mm x 5mm Surface Mount BGA Package Applications n n n Isolated USB Interfaces Host, Hub, or Device Isolation Industrial/Medical Data Acquisition L, LT, LTC, LTM, Linear Technology, the Linear logo and Module are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LTM(R)2884 is a complete galvanically isolated USB 2.0 compatible Module(R) (micromodule) transceiver. An upstream supply powers both sides of the interface through an integrated, isolated DC/DC converter. The LTM2884 is ideal for isolation in host, hub, bus splitter or peripheral device applications. It is compatible with USB 2.0 full speed (12Mbps) and low speed (1.5Mbps) operation. Automatic speed selection configures integrated pull-up resistors on the upstream port to match those sensed on the downstream device. The isolator Module technology uses coupled inductors and an isolated power transformer to provide 2500VRMS of isolation between the upstream and downstream USB interface. This device is ideal for systems requiring isolated ground returns or large common mode voltage variations. Uninterrupted communication is guaranteed for common mode transients greater than 30kV/s. Enhanced ESD protection allows this part to withstand up to 15kV (human body model) on the USB transceiver interface pins to local supplies and 15kV through the isolation barrier to supplies without latch-up or damage. Typical Application Powered 2.5W Isolated Hub Port VBUS 8.6V TO 16.5V VCC VBUS LTM2884 VCC2 VLO PWR ISOLATION BARRIER ON SPNDPWR HUB C D1+ 15k + D2+ VCC LTM2884 VCC2 VLO PWR ON 100F VLO2 DOWNSTREAM USB PORT D2- GND VBUS VBUS2 SPNDPWR D1- 15k 200mA AT 5V 500mA AT 5V D1+ UPSTREAM USB PORT PERIPHERAL ISOLATION BARRIER 4.4V TO 16.5V Bus Powered 1W Isolated Peripheral Device VLO2 1.5k D2+ D1- GND2 D2- GND GND GND2 2884 TA01b 2884 TA01a 2884fb For more information www.linear.com/LTM2884 1 LTM2884 Absolute Maximum Ratings Pin Configuration (Note 1) TOP VIEW Supply Voltages VCC to GND............................................. -0.3V to 18V VBUS to GND........................................... -0.3V to 18V VCC2 to GND2........................................ -0.3V to 10V VLO to GND................................................... -0.3V to 4V VLO2 to GND2................................................ -0.3V to 4V ON, SPNDPWR to GND..................-0.3V to (VLO + 0.3V) D1+, D1- to GND......................................... -0.3V to 5.3V D2+, D2- to GND2...................................... -0.3V to 5.3V Operating Ambient Temperature Range (Note 3) LTM2884C................................................ 0C to 70C LTM2884I.............................................-40C to 85C LTM2884H.......................................... -40C to 105C Storage Temperature Range................... -55C to 125C Maximum Internal Operating Temperature............. 125C Peak Body Reflow Temperature............................. 245C 1 A 2 3 4 5 6 7 8 9 SPNDD1- D1+ PWR ON VLO GND VBUS 10 11 VCC B GND C D E F G H J GND2 K L D2- D2+ GND2 VLO2 GND2 VCC2 BGA PACKAGE 44-LEAD (15mm x 15mm x 5mm) TJMAX = 125C, PCB = JESD51-9 2s2p: JA = 18.7C/W, JCtop = 16C/W, JCbottom = 5.7C/W, JB = 5.6C/W PCB = DC1746A: JA = 33.5C/W, JCtop = 15.7C/W, JCbottom = 6.1C/W, JB = 5.3C/W HEAT FLOW: JA = NORMAL, JCtop = 100%, JCbottom = 100%, JB = 100% WEIGHT = 2.4g Order Information http://www.linear.com/product/LTM2884#orderinfo PART MARKING PART NUMBER PAD OR BALL FINISH DEVICE FINISH CODE PACKAGE TYPE MSL RATING LTM2884CY#PBF LTM2884IY#PBF TEMPERATURE RANGE 0C to 70C SAC305 (RoHS) LTM2884Y e1 BGA LTM2884HY#PBF 4 -40C to 85C -40C to 105C * Device temperature grade is indicated by a label on the shipping container. * Recommended BGA PCB Assembly and Manufacturing Procedures: www.linear.com/BGA-assy * Pad or ball finish code is per IPC/JEDEC J-STD-609. * BGA Package and Tray Drawings: www.linear.com/packaging * Terminal Finish Part Marking: www.linear.com/leadfree * This product is moisture sensitive. For more information, go to: www.linear.com/BGA-assy * This product is not recommended for second side reflow. For more information, go to: www.linear.com/BGA-assy 2 2884fb For more information www.linear.com/LTM2884 LTM2884 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V, VBUS = 5V, GND = GND2 = 0V, ON = VLO, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 12 16.5 V 5 16.5 V 100 500 A Power Supply VCC Operating Supply Range (Isolated Power Input) l 4.4 VBUS Operating Supply Range (USB Bus Power Input) l 4.4 VCC Supply Current Power Off ICC IBUS VCC2 ON = 0V, VCC = 4.4V to 16.5V l VCC Supply Current Power On ICC2 = 0mA, Figure 1 l 50 100 mA VBUS Supply Current Power Off ON = 0V l 10 100 A VBUS Supply Current Power On IVLO = 0mA, Figure 1 l 6 9 mA VBUS Supply Current Suspend Mode SPNDPWR = 3.3V USB Suspend Timeout SPNDPWR = 0, USB Suspend Timeout 500 A 1.5 2.0 mA 5 5 5.25 5.25 V V l l Regulated VCC2 Output Voltage, Loaded VCC = 4.4V, ICC2 = 200mA, Figure 1 VCC = 8.6V, ICC2 = 500mA, Figure 1 l l 4.75 4.75 VCC2 Source Current High Power Mode VCC = 8.6V, Figure 1 l 500 mA VCC2 Source Current Bus Power Mode VCC = VBUS = 4.4V, Figure 1 l 200 mA VLO VLO Regulated Output Voltage IVLO = 0mA to 10mA, Figure 1 l 3.15 3.3 3.45 VLO Output Voltage Maximum Current Figure 1 l VLO2 VLO2 Regulated Output Voltage IVLO2 = 0mA to 10mA, Figure 1 l 3.15 3.3 3.45 VLO2 Output Voltage Maximum Current Figure 1 l 10 10 V mA V mA USB Input Levels (D1+, D1-, D2+, D2-) VIH Single-Ended Input High Voltage l VIL Single-Ended Input Low Voltage l VHYS Single-Ended Input Hysteresis VDIFF Differential Input Sensitivity |(D1+ - D1-)| or |(D2+ - D2-)| l 0.2 Common Mode Voltage Range |(D1+ + D1-)|/2 l 0.8 2.0 VCM 2.0 V 0.8 200 or |(D2+ + D2-)|/2 V mV V 2.5 V Logic Input Levels (ON, SPNDPWR) VIHL Logic Input High Voltage l VILL Logic Input Low Voltage l 0.8 V V IINL Logic Input Current l 1 A VHYSL Logic Input Hysteresis 200 mV USB Output Levels (D1+, D1-, D2+, D2-) VOL Output Low Voltage RPU = 1.5k to 3.6V, Figure 4 l 0 0.3 V VOH Output High Voltage RPD = 15k to 0V, Figure 4 l 2.8 3.6 V VCRS Differential Output Signal Cross-Point Voltage l 1.3 2.0 V 1.425 1.575 k 14.25 15.75 k Terminations Bus Pull-Up Resistance on Upstream Facing Port D2+ or D2- Pull-Up to 3.3V RPD Bus Pull-Down Resistance on Downstream Facing Port D2+ and D2- Pull-Down to GND2 ZDRV USB Driver Output Resistance CINUSB USB Transceiver Pad Capacitance to GND RPU l (Note 2) 28 44 10 pF 2884fb For more information www.linear.com/LTM2884 3 LTM2884 Switching Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V, VBUS = 5V, GND = GND2 = 0V, ON = VLO, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Low Speed USB t LDR Low Speed Data Rate CL = 50pF to 450pF (Note 4) t LR Rise Time Figure 2, CL = 50pF to 600pF l 75 1.5 300 ns t LF Fall Time Figure 2, CL = 50pF to 600pF l 75 300 ns t LPRR, t LPFF Propagation Delay Figure 2, CL = 50pF to 600pF l 300 ns t LDJ1 Differential Jitter To Next Transition (Note 2) 45 ns t LDJ2 Differential Jitter To Paired Transitions (Note 2) 15 ns t FDR Full Speed Data Rate CL = 50pF (Note 4) 200 Mbps Full Speed USB 12 Mbps t FR Rise Time Figure 3, CL = 50pF l 4 20 ns t FF Fall Time Figure 3, CL = 50pF l 4 20 ns t FPRR, t FPFF Propagation Delay Figure 3, CL = 50pF l 60 115 ns t FDJ1 Differential Jitter To Next Transition (Note 2) 2 ns t FDJ2 Differential Jitter To Paired Transitions (Note 2) 1 ns 80 Power Supply Generator t WUSPND VCC2 - GND2 Supply Start-Up Time (ON VLO, VCC2 to 4.5V) RLOAD = 50, CLOAD = 100F RLOAD = 10, CLOAD = 100F, VCC = 12V l l 2 3 5 10 ms ms Wake Up from Suspend Mode Resume Signal, SPNDPWR = 0 l 0.25 10 s ESD (HBM) (Note 2) Isolation Barrier D1+, D1-, D2+, D2- GND to GND2 15 kV D1+/D1- to GND, VCC, VBUS, or VLO and D2+/D2- to GND2, VCC2, or VLO2 15 kV 3 kV ON, SPNDPWR Isolation Characteristics SYMBOL PARAMETER TA = 25C. CONDITIONS MIN TYP MAX UNITS Rated Dielectric Insulation Voltage (Notes 6, 7) 1 Minute (Derived from 1 Second Test) 2500 1 Second (Note 5) 3000 VRMS Common Mode Transient Immunity VBUS = VCC = 5V, ON = 3.3V, 1000V in 33ns Transient Between GND and GND2 (Note 2) 30 kV/s Maximum Working Insulation Voltage (Notes 2, 5) 560 400 VPEAK VRMS Partial Discharge VPR = 750VRMS (Note 5) Comparative Tracking Index IEC 60112 (Note 2) Depth of Erosion IEC 60112 (Note 2) Distance Through Insulation (Note 2) Isolation Barrier: GND to GND2 VISO VIORM CTI DTI 4 VRMS <5 600 pC VRMS 0.017 mm 0.1 mm 1012 Input to Output Resistance (Notes 2, 5) Input to Output Capacitance (Notes 2, 5) 13 pF Creepage Distance (Notes 2, 5) 9.48 mm 2884fb For more information www.linear.com/LTM2884 LTM2884 Electrical Characteristics 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 production tested. Note 3: This Module transceiver includes over temperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125C when over temperature protection is active. Continuous operation above specified maximum operating junction temperature may result in device degradation or failure. Note 4: Maximum data rate is guaranteed by other measured parameters and is not directly tested. Note 5: Device considered a 2-terminal device. Measurement between groups of pins A1 through B11 shorted together and pins K1 through L11 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 2500VRMS rating by applying the equivalent positive and negative peak voltage multiplied by an acceleration factor of 1.2 for one second. 2884fb For more information www.linear.com/LTM2884 5 LTM2884 Typical Performance Characteristics TA = 25C, VCC = 5V, VBUS = 5V, GND = GND2 = 0V, ON = 3.3V, unless otherwise noted. Full Speed Propagation Delay vs Temperature 100 Low Speed Propagation Delay vs Temperature 250 CLOAD = 120pF PROPAGATION DELAY (ns) PROPAGATION DELAY (ns) 95 90 85 80 75 Full Speed Differential Jitter CLOAD = 120pF D1- 240 D1+ 230 1V/DIV D2- 220 210 -25 0 50 25 75 TEMPERATURE (C) 100 200 -50 125 -25 25 75 0 50 TEMPERATURE (C) 100 VCC2 Output Current vs Temperature Low Speed Differential Jitter 800 D1+ JITTER 7.5nsP-P 2884 G04 50ns/DIV VCC = 5V 60 VCC = 12V 600 EFFICIENCY (%) D2+ OUTPUT CURRENT (mA) 1V/DIV 70 500 400 VCC = 5V 300 200 -50 -25 1.0 50 0.8 40 VCC = 5V 30 0 50 25 75 TEMPERATURE (C) 100 125 0 0.2 0.2 0 200 4.75 VCC = 5V 4.50 VCC = 4.4V 4.25 0.35 0.30 0.25 0.20 0.15 0.05 0 0.4 0.2 0.6 OUTPUT CURRENT (A) 0.8 2884 G07 2884 G06 0.40 0.10 50 4.00 0 0.8 0.45 VCC = 12V 150 100 0.6 0.50 VCC = 8.1V 300 250 0.4 IOUT (A) 0.55 5.00 VCC2 (V) INPUT CURRENT (mA) 350 VCC = 12V 0.4 Derating for 125C Maximum Internal Operating Temperature LOAD CURRENT (A) VCC = 5V 0.6 20 5.25 400 VCC = 12V POWER LOSS VCC2 Output Voltage vs Load Current 450 1.2 VCC = 12V 2884 G05 VCC Input Current vs VCC2 Output Current 1.4 EFFICIENCY POWER LOSS (W) D1- VCC to VCC2 Efficiency and Power Loss VCC2 = 4.75V 700 D2- 125 2884 G02 2884 G01 6 2884 G03 10ns/DIV 70 -50 0 JITTER 1.4nsP-P D2+ 0 0.2 0.6 0.4 LOAD CURRENT (A) 0.8 1.0 2884 G08 0 VBUS - VCC = 5V VBUS - VCC = 8.6V VBUS - VCC = 12V VBUS - VCC = 16.5V 25 35 45 55 65 75 85 95 105 115 125 TEMPERATURE (C) 2884 G09 2884fb For more information www.linear.com/LTM2884 LTM2884 Typical Performance Characteristics ON = 3.3V, unless otherwise noted. VCC2 Ripple, VCC = 5V, ICC2 = 200mA TA = 25C, VCC = 5V, VBUS = 5V, GND = GND2 = 0V, VCC2 Ripple, VCC = 12V, ICC2 = 500mA VCC2 Start-Up Ramp VCC2 100mV/DIV 100mV/DIV 2s/DIV 2884 G10 2884 G11 2s/DIV VCC2 = Load Step Response, 0mA to 500mA (VCC = 12V) VCC2 = Load Step Response, 0mA to 200mA (VCC = 5V) ICC vs Temperature ICC2 500mV/DIV VCC2 100s/DIV 2884 G13 ICC2 = 0mA VCC = 4.4V 60 ICC2 SUPPLY CURRENT (mA) 500mV/DIV 200mA/DIV VCC2 100s/DIV 2884 G12 500s/DIV 70 200mA/DIV ON 1V/DIV 2884 G14 VCC = 5V 50 40 VCC = 8.1V 30 VCC = 12.5V 20 VCC = 16.5V 10 0 -50 -25 25 50 75 0 TEMPERATURE (C) 100 125 2884 G15 Upstream VBUS Droop During Plug-In with CLOAD = 100F VCC2 Droop/Plug-In Response Full Speed Data Start of Packet VCC D2+ HOST VBUS VCC2 1V/DIV 1V/DIV PLUG IN TO HOST 500mV/DIV ISOLATED VCC2 D2- 200s/DIV 2884 G16 500s/DIV 2884 G16 100ns/DIV 2884 G17 2884fb For more information www.linear.com/LTM2884 7 LTM2884 Pin Functions Upstream Side (VCC, VBUS, VLO, GND) Isolated Downstream Side (VCC2, VLO2, GND2) D1- (A1): USB Data Bus Upstream Facing Negative Transceiver Pin. A 1.5k pull-up resistor is automatically configured to indicate the idle condition of the D2- pin. GND2 (K1-K11, L3, L4, L6, L7): Downstream Circuit Ground. D1+ (A2): USB Data Bus Upstream Facing Positive Transceiver Pin. A 1.5k pull-up resistor is automatically configured to indicate the idle condition of the D2+ pin. SPNDPWR (A3): Suspend Power Control. A high input enables the DC/DC converter shutdown control if the USB bus is suspended. A low input (GND) disables the shutdown control to the DC/DC converter maintaining power to the isolated downstream side during suspend mode. The recovery time from suspend mode may be equivalent to the power supply start-up time if the DC/DC converter was shut down. The SPNDPWR pin is referenced to VLO and GND. ON (A4): Enable for Power and Data Communication Through the Isolation Barrier. If ON is high, the part is enabled. If ON is low, the upstream side is held in reset and the isolated side is unpowered by the DC/DC converter. The ON pin is referenced between VLO and GND. D2 - (L1): USB Data Bus Downstream Facing Negative Transceiver Pin. The pin has a 15k pull-down resistor to GND2. D2+ (L2): USB Data Bus Downstream Facing Positive Transceiver Pin. The pin has a 15k pull-down resistor to GND2. VLO2 (L5): Internally Regulated 3.3V Logic Voltage Output. The VLO2 pin can source up to 10mA of surplus current. Internally bypassed to GND2 with 2.2F. Output supply, no external connection necessary. VCC2 (L8-L11): Isolated Voltage Supply Output from DC/ DC Converter. Output voltage is 5V and can support up to 500mA of peripheral device current referenced to GND2. Output current is dependant on input supply voltage and current limit. Internally bypassed to GND2 with 22F. Output supply, no external connection necessary. VLO (A5): Internally Regulated 3.3V Logic Voltage Output. The VLO pin is used as a positive reference for the ON and SPNDPWR pins and can source up to 10mA of surplus current. Internally bypassed to GND with 2.2F. Output supply, no external connection necessary. GND (A6, B1-B11): Upstream Circuit Ground. VBUS (A7): Voltage Supply Input to USB Transceiver. The operating range is 4.4V to 16.5V. Connect to the USB VBUS supply or an external source. Internally bypassed to GND with 2.2F. VCC (A8-A11): Voltage Supply Input to DC/DC Converter. The operating range is 4.4V to 16.5V. Connect to an external supply greater than 8.6V for 500mA on VCC2,VBUS must be connected to the external supply or USB power. Connect to the USB VBUS for up to 200mA on VCC2. Connect VCC to VBUS when the peripheral device has an external power source. Internally bypassed to GND with 4.7F. 8 2884fb For more information www.linear.com/LTM2884 LTM2884 Block Diagram VBUS VCC 2.2F 4.7F VCC2 22F DC/DC VLO2 3.3V REG 3.3V REG 2.2F VLO 2.2F ISOLATED COMMUNICATION INTERFACE ON D1+ UPSTREAM PORT 1.5k ISOLATED COMMUNICATION INTERFACE 1.5k D2+ D2- D1- 15k SPNDPWR GND DOWNSTREAM PORT 15k GND2 2884 BD = UPSTREAM SIDE COMMON = DOWNSTREAM SIDE COMMON 2884fb For more information www.linear.com/LTM2884 9 LTM2884 Test Circuits ICC LTM2884 VCC2 VCC IBUS VLO + - VCC + - VBUS IVLO ISOLATION BARRIER VBUS VLO2 IVLO2 ICC2 GND2 GND 2884 F01 Figure 1. Power Supply Loads 10 2884fb For more information www.linear.com/LTM2884 LTM2884 Test Circuits D1+ OR D2+ D2+ OR D1+ 3.3V CL 0V 3.6V D1- OR D2- 3.3V 1.5k D2- OR D1- 0V D1- OR D2- D1+ OR D2+ tLPRR tLPFF D2- OR D1- D2+ OR D1+ 90% 10% 90% 10% 2884 F02 CL tLR tLF Figure 2. Low Speed Timing Measurements D1+ OR D2+ D2+ OR D1+ 3.3V CL 0V 3.3V D1- OR D2- D2- OR D1- 0V D1+ OR D2+ D1- OR D2- tFPFF tFPRR D2+ OR D1+ D2- OR D1- 90% 10% CL 90% 10% 2884 F03 tFF tFR Figure 3. Full Speed Timing Measurements 2884fb For more information www.linear.com/LTM2884 11 LTM2884 Functional Table USB Transceiver Functional Table D1+ MODE D1- AUTOMATIC PULL-UP CONNECTION D2+ Full Speed (Idle) 1.5k Pull-Up Host Pull-Down D1+ Low Speed (Idle) Host Pull-Down 1.5k Pull-Up D1- D2- SPNDPWR Peripheral Pull-Up 15k Pull-Down X 15k Pull-Down Peripheral Pull-Up X Disconnected (Idle) Host Pull-Down Host Pull-Down None 15k Pull-Down 15k Pull-Down X Suspend (Idle >3ms) Set at Device Connect Set at Device Connect Set at Device Connect Peripheral or 15k Peripheral or 15k 0 Suspend No Power (Idle >3ms) Set at Device Connect Set at Device Connect Set at Device Connect 15k Pull-Down 15k Pull-Down 3.3V D1 to D2 Data IN+ IN- Set at Device Connect OUT+ OUT- X D2 to D1 Data OUT+ OUT- Set at Device Connect IN+ IN- X Power Functional Table MODE ON SPNDPWR VCC VBUS DC/DC CONVERTER Off 0 X X X OFF On 3.3V X >4.4V >4.4V ON On, Suspend (Idle >3ms) 3.3V 0 >4.4V >4.4V ON On, Suspend (Idle >3ms), Power Off 3.3V 3.3V >4.4V >4.4V OFF On, USB Transceiver Only Power Off 3.3V X 0 >4.4V OFF 12 2884fb For more information www.linear.com/LTM2884 LTM2884 Operation The LTM2884 Module transceiver provides a galvanically isolated robust USB interface, powered by an integrated, regulated DC/DC converter, complete with decoupling capacitors. This flexible device can support a variety of USB configurations, either bus powered or externally powered. Applications include isolation in hosts, hubs, peripherals, or standalone inline bus splitters. Automatically configured pull-up resistors are included to represent the condition of the isolated downstream USB bus to the upstream USB bus. The LTM2884 is ideal for use in USB connections where grounds between upstream hub/host and downstream devices can take on different voltages. Isolation in the LTM2884 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 exceeding 30kV/s providing excellent noise isolation. The LTM2884 contains a fully integrated DC/DC converter including the transformer, so that no external components are necessary in many configurations. The upstream side contains a flyback converter that regulates the downstream output voltage through primary sensing techniques. The internal power solution is sufficient to support the transceiver interface and supply up to 500mA at 5V through VCC2 to an attached device dependent on the supply voltage and available current on VCC. The integrated USB transceivers on both sides of the isolation barrier support full and low speed modes defined in the USB 2.0 specification. The communication through the isolation barrier for USB is bidirectional and as such the LTM2884 determines data flow direction based on which side a start of packet (SOP) begins first. The direction of data is maintained until an end of packet (EOP) pattern is observed or a timeout occurs due to a lack of activity. The USB interface maintains a consistent propagation delay representative of a hub delay and transfers all data. Pull-up resistors integrated in the upstream interface automatically indicate device connections and disconnections. A downstream device connection automatically selects the proper pull-up resistor at the upstream facing port after sensing the idle state of the downstream device at connection time. Disconnection of a downstream device automatically releases the pull-up resistor on the upstream facing port allowing the upstream 15k pull-down resistors to pull the bus signals to a disconnect condition. This function makes the LTM2884 ideal for host, hub, bus splitter, or peripheral device integration. Isolator Module Technology The LTM2884 utilizes isolator Module 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 differential signaling through coreless transformers formed in the Module 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 Module technology provides the means to combine the isolated signaling with a USB transceiver and powerful isolated DC/DC converter in one small package. USB Transceiver Pin Protection The LTM2884 USB transceiver pins D1+, D1-, D2+, and D2- have protection from ESD and short-circuit faults. The transceiver pins withstand 15KV HBM ESD events. Overcurrent circuitry on the transceiver pins monitor fault conditions from D1+ and D1- to GND, VLO, or VBUS and from D2+ and D2- to GND2, VLO2, or VCC2. A current detection circuit disables the transceiver pin if the pin sinks about 40mA for greater than 600ns. The VLO and VLO2 output supplies protect the USB transceiver pins from shorts to GND or GND2 respectively with a 40mA current limit. 2884fb For more information www.linear.com/LTM2884 13 LTM2884 Applications Information Idle State Communication and Automatic Speed Selection USB Connectivity The LTM2884 Module transceiver connects directly to USB ports on the upstream side and the downstream side without the addition of external components. The transceiver passes through all data and does not act as a hub or intelligent device. The bus lines are monitored for idle conditions, start of packet, and end of packet conditions to properly maintain bus speed and data direction. The series resistance, pull-up, and pull-down resistors are built into the LTM2884. The upstream facing USB port contains automatically configured 1.5k pull-up resistors which are switched in or out based on the downstream side peripheral device configuration. This implementation allows upstream reporting of the downstream bus speed and connection/disconnection conditions. Built-in 15k pulldown resistors are included from the D2+ and D2- signals to GND2 supporting the downstream bus configuration. The LTM2884 Module transceiver maintains the conditions of the USB bus idle state by monitoring the downstream side bus idle condition and refreshing the state across the isolation barrier at a consistent rate. Furthermore, the LTM2884 monitors the speed of the downstream peripheral once connected and sets its own operation to match. Figure 4 shows the abbreviated circuitry of the automatic monitoring and reporting of the bus speeds. The D2+ or D2- signals are monitored for a connection to pull-ups on D2+ or D2- and the result is processed as full speed or low speed, otherwise disconnect. The idle state is communicated to the upstream side through a refresh transmission. The switches SW1 or SW2 are controlled based on the received information. SW1 is closed if D2+ is detected to have a pull-up and D2- was open. SW2 is closed if D2- is detected to have a pull-up and D2+ was open. Both SW1 and SW2 are opened if the downstream USB bus is disconnected. During a USB suspend, the pullup resistor will maintain the condition prior to detecting the suspend command. Monitoring the USB data pins, the LTM2884 detects a K-state to begin a data packet and set the data direction. The data is monitored for an end of packet signature and a finishing J-state before the bus is released. The data payload between the K-state and J-state is transferred through the LTM2884 isolator with a delay of approximately 80ns. UPSTREAM CONNECTION DOWNSTREAM CONNECTION LTM2884 3.3V SW1 D1+ D1- 15k 15k RPU 1.5k SW2 RPU 1.5k ISOLATION BARRIER VLO REFRESH 3.3V FULL SPEED LOW SPEED 1.5k 1.5k D2+ D2- RPD 15k RPD 15k OR OR DISCONNECTED 2884 F04 Figure 4. Idle State Automatic Resistor Setting 14 2884fb For more information www.linear.com/LTM2884 LTM2884 Applications Information Suspend Mode DC/DC Power Supply When the upstream USB bus is idle for greater than 3ms, the LTM2884 enters suspend mode. The power savings and behavior in suspend mode depend on the state of the SPNDPWR pin, as summarized in Table 1. The internal DC/DC converter converts the input power from the VCC pin to the VCC2 output. The power delivered to the VCC2 pin is regulated and current limited to protect against overcurrent conditions. The voltage supply, VCC , is sensed to limit the maximum current that can be delivered before USB specifications are exceeded. Connecting the VCC and VBUS supply pins to the USB VBUS pin (4.4V to 5.5V) limits the maximum downstream side supply current to 200mA before VCC2 supply degradation. When VCC is connected to a high voltage external DC source (8.6V to 16.5V) the current limit is increased so that 500mA is sourced from VCC2. If a downstream device sinking current from VCC2 draws more than 25mA, the input current on VCC may exceed 100mA, the USB single unit load specification for low power devices. The LTM2884 does not enforce a 100mA current limit for low power peripherals. Table 1. Suspend Mode Operation WAKE-UP WAKE-UP TIME SPNDPWR VCC2 IBUS ICC High Off < 500A VCC/45k Resume 3ms Low On 1.5mA 50mA Resume or Remote Wake-Up 10s The biggest power savings in suspend mode comes when SPNDPWR is high. In this case, the DC/DC converter is disabled, shutting down power to the isolated side, while the current draw on VCC and VBUS are minimized. However, in this mode, if a downstream device is connected or disconnected from the bus or remote wake-up functionality is configured, it will not be recognized by the LTM2884 and will not be relayed to the host. A resume command at the upstream side will wake up the LTM2884 and a renumeration by the host will be required. Recovery time is about 3ms from the start of the resume command on the upstream side. If SPNDPWR is low in suspend mode, the LTM2884 operates in a low power mode but maintains a higher functional state with the DC/DC converter on and the downstream transceiver powered. The VBUS current is reduced to 1.5mA and VCC current is about 50mA when there is no external draw on VCC2. Wake-up is initiated with disconnects, reconnects, or a remote wake-up command from a downstream device or a resume command from the host. Recovery time from suspend mode is about 10s from when the first state change is detected. During suspend mode DC current drawn from VLO into external circuits will be supplied from VBUS and may exceed the limits set in the USB specification. VCC2 is internally decoupled to GND2 with a 22F capacitor. Add an additional low ESR 100F capacitor to VCC2 to meet the VBUS downstream supply decoupling minimum specification of 120F when supporting device plug in. Locate the additional 100F capacitor adjacent to the downstream USB connector. Additional capacitance may not be necessary when the LTM2884 is used in a peripheral device, or upstream hub application. VLO and VLO2 Supplies The VLO and VLO2 output supply pins are available for use as low current 3.3V supplies on both sides of the isolation barrier. They also serve as supplies for the USB interface circuitry. An internal linear regulator maintains 3.3V on VLO from the VBUS input supply. A separate linear regulator maintains 3.3V on VLO2 from VCC2. The current is limited to 10mA for external applications. Exceeding this limit may cause degradation in the VLO or VLO2 supplies and undesirable operation from the USB isolator. Connection of signals ON or SPNDPWR to VLO will not cause a significant change in the available VLO current. These supplies are available to support interface logic to the isolated USB port. In order to meet the suspend mode current limit, minimize the DC current of external applications on the VLO output supply. VLO and VLO2 are protected from overcurrent and overtemperature conditions. 2884fb For more information www.linear.com/LTM2884 15 LTM2884 Applications Information Supply Current Loading the multiple output supply pins of the LTM2884 affects the supply current on VBUS and VCC. The VBUS input supplies current to the the upstream side of the transceiver and to the VLO pin. The VCC input supplies power to VCC2 and VLO2 through an isolated DC/DC converter. The efficiency () of the DC/DC converter is shown in the Typical Performance Characteristics section for 5V and 12V inputs from VCC to VCC2. Supply Current Equations IBUS = 6mA + IVLO ( VCC2 * 6mA + ICC2 + IVLO2 * VCC ) Suspend: SPNDPWR = 0 IBUS = 1.5mA + IVLO ICC = ( VCC2 * 6mA + ICC2 + IVLO2 * VCC ) Suspend: SPNDPWR = VLO IBUS = 0.45mA + IVLO ICC = VCC 45k Off: IBUS = 10A ICC = VCC 45k USB 2.0 Compatibility The LTM2884 Module transceiver is compatible with the USB 2.0 specification of full and low speed operation. Some characteristics and implementations may not support full compliance with the USB 2.0 specification. Three specific 16 First, the propagation delay for full speed data of 80ns exceeds the specification for a single hub of 44ns plus the attached cable delay of 26ns. This is due to driving the signal to the 3.3V rail prior to a K-state transition to maintain balanced crossover voltages equivalent to the cross over voltages of the successive data transitions. USB ports commonly drive the idle state bus to the 3.3V rail prior to the k-state start of packet transition. Second, setting SPNDPWR = VLO will cause the DC/DC power converter to turn off during a bus suspend. VCC2 will lose power causing the downstream device to lose enumeration. Remote wake-up, disconnect, and reconnect events are ignored. A resume command from the host or upstream hub will start the DC/DC converter and wake up the downstream device. The downstream device will require re-enumeration, which causes a failure in USB compliance testing. After a resume command initiates, a delay of 3ms will elapse before the isolated device is fully powered. When SPNDPWR = 0V, the DC/DC power converter remains on during suspend, therefore power and enumeration information is retained. The VCC supply consumes 50mA to support the isolated power during suspend. Separate the VBUS and VCC supplies to comply with the 2.5mA USB 2.0 VBUS suspend current specification. Operating: ICC = cases exist within the LTM2884 Module transceiver and the integrated DC/DC power converter. Third, when connecting a low power device to the downstream side of the LTM2884 and VBUS and VCC are connected together, the input current is higher due to the operating current and the efficiency of the DC/DC converter. The operating current of the DC/DC converter and the USB transceiver function is 46mA. The efficiency of the converter is approximately 55%, resulting in a 1/0.55 increase in the input current due to the load current on VCC2. A 100mA load on VCC2 appears as a 181mA load + operating current at VBUS and VCC. In order to meet a 100mA input current, the VCC2 load current must be less than 25mA. This characteristic of an isolated supply may limit the use of the LTM2884 in bus powered hub applications or downstream connection to a bus powered hub. Connect VCC to an external supply to mitigate this concern. 2884fb For more information www.linear.com/LTM2884 LTM2884 Applications Information Hot Plug Protection RF, Magnetic Field Immunity The VCC and VBUS inputs are bypassed with low ESR ceramic capacitors. During a hot plug event, the supply inputs can overshoot the supplied voltage due to cable inductance. When using external power supply sources greater than 10V that can be hot plugged, add an additional 2.2F tantalum capacitor with greater than 1 of ESR, or a ceramic capacitor with a series 1 resistor to the VCC input to reduce the possibility of exceeding absolute maximum ratings. Refer to Application Note 88, "Ceramic Capacitors Can Cause Overvoltage Transients," for a detailed discussion of this problem. The isolator Module technology used within the LTM2884 has been independently evaluated, and successfully passed the RF and magnetic field immunity testing requirements per European Standard EN 55024, in accordance with the following test standards: PC Board Layout Tests were performed using an unshielded test card designed per the data sheet PCB layout recommendations. Specific limits per test are detailed in Table 2. The high integration of the LTM2884 makes PCB layout simple. However, to optimize its electrical isolation characteristics, EMI, and thermal performance, some layout considerations are necessary. The PCB layout in Figure 5 is a recommended configuration for a low EMI USB application. The following considerations optimize the performance of the LTM2884: * Under loaded conditions, VCC and GND current exceed 700mA, VCC2 and GND2 current is up to 500mA. Use sufficient copper on the PCB to ensure resistive losses do not cause the supply voltage to drop below the minimum allowed level. The heavy copper traces will also help to reduce thermal stress and improve thermal conductivity. * Input and output decoupling is not required on peripheral or hub inputs. Add additional low ESR capacitance to reduce noise induction on the power supply connections. Hub/bus splitter outputs require an additional 100F of low ESR capacitance. EN 61000-4-3 Radiated, Radio-Frequency, Electromagnetic Field Immunity EN 61000-4-8 Power Frequency Magnetic Field Immunity EN 61000-4-9 Pulsed Magnetic Field Immunity Table 2. Test Frequency Field Strength EN 61000-4-3, Annex D, 80MHz to 1GHz 1.4MHz to 2GHz 2GHz to 2.7GHz 10V/m 3V/m 1V/m EN 61000-4-8, Level 4 50Hz and 60Hz 30A/m EN 61000-4-8, Level 5 60Hz 100A/m* EN 61000-4-9, Level 5 Pulse 1000A/m *Non IEC Method EMI Radiated emissions have been measured for the LTM2884 using a gigahertz transverse electromagnetic (GTEM) cell with and without a USB cable attached. The performance shown in Figure 6 was achieved with the layout structure in Figure 5. Results are corrected per IEC 61000-4-20. * Do not place copper between the inner columns of pads on the top or bottom of the PCB. This area must remain open to withstand the rated isolation voltage and maintain the creepage distance. 2884fb For more information www.linear.com/LTM2884 17 LTM2884 Applications Information TECHNOLOGY DC1789a Demo Board DC1789a Top DC1789a Bottom 2884 F04 Figure 5. PC Board Layout 60 50 CISPR 22 CLASS B LIMIT 40 dBV/m 30 20 10 0 -10 -20 -30 DETECTOR = PEAK-HOLD RBW = 120kHz VBW= 300kHz SWEEP TIME = 680ms # OF POINTS = 501 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) 2884 F06 Figure 6. EMI Plot 18 2884fb For more information www.linear.com/LTM2884 LTM2884 Typical Applications 100mA OR 500mA 5V 25mA OR 200mA VBUS VBUS VCC LTM2884 ISOLATION BARRIER ON SPNDPWR UPSTREAM USB PORT D+ D- VBUS2 VCC2 VLO D1+ PWR 100F VLO2 ISOLATED DOWNSTREAM USB PORT D2+ D1- D+ D2- GND D- GND2 GND2 GND 2884 F07 Figure 7. Bus Powered Inline Bus Splitter 5V VBUS VBUS VCC LTM2884 VCC2 VLO SPNDPWR UPSTREAM TO USB HOST D+ D- D1+ ISOLATION BARRIER ON PWR DA+ DA- USB HUB CONTROLLER DB+ DB- VLO2 4 USB DOWNSTREAM DC+ PORTS DC- D2+ D1- D2- DD+ DD- GND GND2 GND 2884 F08 GND2 Figure 8. USB Hub Upstream Isolator 2884fb For more information www.linear.com/LTM2884 19 LTM2884 Typical Applications 4.4V TO 16.5V VBUS VCC 5V UP TO 200mA FOR VCC 4.4V TO 5.5V 500mA FOR VCC 8.6V TO 16.5V LTM2884 ON PWR ISOLATION BARRIER SPNDPWR USB HOST CONTROLLER D1+ 100F VLO2 DOWNSTREAM USB PORT D2+ D1- 15k VBUS2 VCC2 VLO D+ D2- D- 15k GND GND2 GND2 2884 F09 Figure 9. USB Host Integration 5V VBUS VBUS VCC LTM2884 VCC2 VLO SPNDPWR UPSTREAM USB PORT D+ D- D1+ ISOLATION BARRIER ON PWR PERIPHERAL VLO2 D2+ D1- D2- GND GND2 2884 F10 GND Figure 10. Powered Peripheral Device with USB Isolation and Low Current Suspend 20 2884fb For more information www.linear.com/LTM2884 LTM2884 Typical Applications SiA921EDJ VIN GND CTL 200mA FOR VCC 4.4V TO 5.5V 500mA FOR VCC 8.6V TO 16.5V VBUS LTC4412 SENSE GATE STAT VCC VCC2 ON SPNDPWR 9V TO 16V (500mA) Si4230DY-TI-GE3 VPLUG UPSTREAM USB PORT 150k PWR PERIPHERAL VLO2 D2+ D1- D- GATE VOUT FAULT GND D2- GND GND2 2884 F11 GND 4.75k OVERVOLTAGE = 16.7V UNDERVOLTAGE = 8.1V Figure 11. Bus or Self Powered USB Isolation with Low Current Suspend and Power Plug Detection 4.4V TO 16.5V (500mA) VPLUG 200mA FOR VCC 4.4V TO 5.5V 500mA FOR VCC 8.6V TO 16.5V VBUS VCC LTM2884 VCC2 VLO ON OFF ON SPNDPWR D1+ ISOLATION BARRIER 4.99k D1+ D+ LTC4365 VIN SHDN UV OV LTM2884 VLO ISOLATION BARRIER VBUS PWR VLO2 D2+ D1- D2- GND GND 5V GND2 2884 F12 Figure 12. Isolated 1W or 2.5W Power Supply 2884fb For more information www.linear.com/LTM2884 21 aaa Z 0.630 0.025 O 44x 2.540 E SUGGESTED PCB LAYOUT TOP VIEW 1.270 PACKAGE TOP VIEW 0.3175 0.000 0.3175 4 2.540 PIN "A1" CORNER 1.270 22 Y Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. For more information www.linear.com/LTM2884 6.350 5.080 0.000 5.080 6.350 X D aaa Z 3.95 - 4.05 SYMBOL A A1 A2 b b1 D E e F G aaa bbb ccc ddd eee NOM 5.02 0.60 4.42 0.78 0.63 15.0 15.0 1.27 12.70 12.70 DIMENSIONS 0.15 0.10 0.20 0.30 0.15 MAX 5.22 0.70 4.52 0.85 0.66 NOTES DETAIL B PACKAGE SIDE VIEW TOTAL NUMBER OF BALLS: 44 MIN 4.82 0.50 4.32 0.71 0.60 DETAIL A b1 0.37 - 0.47 SUBSTRATE ddd M Z X Y eee M Z DETAIL B MOLD CAP ccc Z A1 A2 A Z F b 10 9 7 G 6 5 4 PACKAGE BOTTOM VIEW 8 e 3 2 1 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 4 7 TRAY PIN 1 BEVEL ! PACKAGE IN TRAY LOADING ORIENTATION Module LTMXXXXXX 3 SEE NOTES L K J H G F E D C B A 7 SEE NOTES PIN 1 BGA 44 1212 REV A PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG Module PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULLY 6. SOLDER BALL COMPOSITION CAN BE 96.5% Sn/3.0% Ag/0.5% Cu OR Sn Pb EUTECTIC 5. PRIMARY DATUM -Z- IS SEATING PLANE BALL DESIGNATION PER JESD MS-028 AND JEP95 3 2. ALL DIMENSIONS ARE IN MILLIMETERS NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 11 DETAIL A COMPONENT PIN "A1" e b (Reference LTC DWG # 05-08-1881 Rev A) Ob (44 PLACES) // bbb Z BGA Package 44-Lead (15mm x 15mm x 5.02mm) LTM2884 Package Description Please refer to http://www.linear.com/product/LTM2884#packaging for the most recent package drawings. 2884fb 6.350 5.080 3.810 3.810 5.080 6.350 LTM2884 Revision History REV DATE DESCRIPTION A 08/16 Added UL-CSA logo in Features list PAGE NUMBER 1 B 11/16 Lowered Storage Temperature to -55C 2 2884fb For more information www.linear.com/LTM2884 23 LTM2884 91k 3.3V MAX4594 SPST IN NO GND COM DP0 DM0 LTC1154 STATUS VS EN DS SD GATE IN GND OVRCUR4 SN74LVC04 27 DP0 DM4 DM0 DP4 12V 27 D4D+ D1+ VCC OVRCUR3 GND PWRON_C PWRON3 DM3 XTAL1 DP3 D3C+ D1+ PWRON_B PWRON2 0.2 VCC ON D2B- D1- 27 D2B+ D1+ LTC1154 STATUS VS DS EN GATE SD GND IN OVRCUR1 VCC 12V EEDATA/ GANGED DM1 DP1 ON D1A- D1- 27 D1A+ D1+ 15k SPNDPWR GND DC+ DC- VBUSB 100F GNDB GND2 VLO2 D2+ USB PORT B DB+ DB- VCC2 VBUSA 100F PWR GNDA GND2 VLO2 USB PORT A D2+ D2- 15k USB PORT C PWR LTM2884 VBUS 27 GND D2+ VCC2 VLO PWRON_A PWRON1 GNDC VLO2 SPNDPWR GND 0.2 VBUSC 100F D2- 12V 51k DD- GND2 15k 3.3V BUSPWR VBUS DD+ PWR LTM2884 VLO 12V USB PORT D VCC2 SPNDPWR GND 27 15k D2+ D2- 12V RESET VLO2 15k LTC1154 STATUS VS DS EN GATE SD GND IN OVRCUR2 DP2 ON 27 3.3V DM2 VBUS D1- 51k SYSTEM POWER-ON RESET 12V GNDD GND2 LTM2884 VLO D3C- 15k XTAL2 VCC 27 6MHz CLOCK SIGNAL 100F SPNDPWR GND 0.2 VBUSD PWR D2- 12V LTC1154 STATUS VS DS EN GATE SD GND IN 4.7F 4.7F VCC2 15k 3.3V 51k 3.3V ON D1- C D LTM2884 VBUS D4D- 15k EXTMEM 3.3V LDO LT1762-3.3 12V 27 SN75240 A B VCC VLO PWRON_D PWRON4 1.5k 27 0.2 ISOLATION BARRIER 47k 12V 51k ISOLATION BARRIER VBUS 3.3V TUSB2046B ISOLATION BARRIER 3.3V V+ ISOLATION BARRIER Typical Application DA+ DA- 2884 F13 Figure 13. Self Powered 4-Port Hub with Independent Isolation Related Parts PART NUMBER LTM2881 LTM2882 LTM2883 LTM2892 LTM2894 DESCRIPTION Complete Isolated RS485/RS422 Module Transceiver + Power Dual Isolated RS232 Module Transceiver with Integrated DC/DC Converter SPI or I2C Module Isolator with Adjustable 12.5V and 5V Regulated Power SPI/Digital or I2C Module Isolator USB Module Isolator 24 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTM2884 (408) 432-1900 FAX: (408) 434-0507 www.linear.com/LTM2884 COMMENTS 2500VRMS Isolation in Surface Mount BGA or LGA 2500VRMS Isolation in Surface Mount BGA or LGA 2500VRMS Isolation in Surface Mount BGA 3500VRMS Isolation, 6 Channels 7500VRMS Isolation 2884fb LT 1116 REV B * PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2014