DEMO MANUAL DC1789A LTM2884 Isolated USB Transceiver with Isolated Power Description Demonstration circuit 1789A is an isolated USB transceiver with isolated power featuring the LTM(R)2884. The demo circuit features an EMI optimized circuit configuration and printed circuit board layout. All components are integrated into the Module(R) isolator. The demo circuit operates from a supply on VCC and/or VBUS. The part generates an isolated output voltage on VCC2 and communicates all Performance Summary SYMBOL PARAMETER necessary signaling across the isolation barrier through LTC's isolator Module technology. Design files for this circuit board are available at http://www.linear.com/demo 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. (TA = 25C) CONDITIONS MIN TYP MAX UNITS VCC Operating Supply Range (Isolated Power Input) 4.4 12 16.5 V VBUS Operating Supply Range (USB Bus Power Input) 4.4 5 16.5 V VCC2 Regulated Output Voltage 4.75 4.75 5 5 5.25 5.25 V V VCC = VBUS = 4.4V, ICC2 = 200mA VCC = 8.1V, ICC2 = 500mA tLDR Low Speed Data Rate 1.5 Mbps tFDR Full Speed Data Rate 12 Mbps VIORM Maximum Working Insulation Voltage GND to GND2 Common Mode Transient Immunity 560 400 VDC VRMS 30 kV/s Operating Principles The LTM2884 contains an isolated DC/DC converter delivering power to VCC2 at 5V from the input supply VCC and/or VBUS. Isolation is maintained by the separation of GND and GND2 where significant operating voltages and transients can exist without affecting the operation of the LTM2884. The logic side ON pin enables or shuts down the LTM2884. All logic side signals are referenced to the logic supply pin VLO. The LTM2884 has two power supply inputs, VCC and VBUS. For applications requiring more than 200mA from VCC2, VCC must be connected to an external supply of 8.1V to 16.5V. VBUS may be connected to USB bus power or to the external supply. For applications requiring 200mA or less connect VCC and VBUS to USB bus power. Upstream USB signaling is controlled by the bidirectional pins D1+ and D1-. A 1.5k pull-up resistor is automatically configured dependent upon the connected downstream peripheral device. For full speed and low speed devices the pull-up is asserted on D1+ and D1-, respectively. The downstream USB data pins, D2+ and D2-, each have integrated 15k pull-down resistors. dc1789afa 1 DEMO MANUAL DC1789A Operating PriNciples The demo circuit has been designed and optimized for low RF emissions. EMI mitigation techniques used include the following: 1. Board/ground plane size has been minimized. This reduces the dipole antenna formed between the logic side and isolated side ground planes. 2. Top signal routing and ground floods have been optimized to reduce signal loops, minimizing differential mode radiation. EMI performance is shown in Figure 1, measured using a gigahertz transverse electromagnetic (GTEM) cell and method detailed in IEC 61000-4-20, "Testing and Measurement Techniques - Emission and Immunity Testing in Transverse Electromagnetic Waveguides." 54 48 42 CISPR 22 CLASS B LIMIT 36 30 dBV/m The LTM2884 includes a suspend power feature that when enabled (high) reduces the supply current on VCC and VBUS when the upstream USB bus is idle. 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 relayed to the host. A resume command at the upstream side will wake up the LTM2884 and a re-numeration by the host will be required. If suspend power is configured low the LTM2884 operates in a low power mode but will respond to disconnects, reconnects, downstream wake-up commands, or host resume commands. 24 18 DC1789A 12 6 0 DETECTOR = PEAK-HOLD RBW = 120kHz, VBW = 300kHz SWEEP TIME = 680ms, 10 SWEEPS # OF POINTS = 501 -6 -12 -18 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) DC1789A F01 Figure 1. DC1789A Radiated Emissions, Normalized to 10m per IEC 61000-4-20 dc1789afa 2 DEMO MANUAL DC1789A Quick Start Procedure Demonstration circuit 1789A makes it easy to set up and evaluate the performance of the LTM2884. Refer to Figure 2 for proper measurement equipment setup and follow the procedure below. NOTE: When measuring the input or output voltage ripple or high speed signals, care must be taken to avoid a long ground lead on the oscilloscope probe. 1. Place jumpers in their default positions: JP1 VCC supply in the VBUS position JP2 VBUS supply in the VBUS position JP3 SUSPEND POWER in the OFF position JP4 C2 in the OUT position NOTE: To simulate a hub/splitter output, C2 can be jumpered IN. The additional capacitance reduces VBUS droop on downstream device plug-in. 2. Connect USB cable from computer to input side (J1) of the demo board. 3. Connect computer mouse, low speed device, or USB memory stick, typically high speed device, to output side (J2) of demo board. 4. Verify proper operation of mouse or memory stick. MEMORY STICK MOUSE Figure 2. Demo Board Setup dc1789afa 3 DEMO MANUAL DC1789A Layer 1. Top Layer PCB Layout dc1789afa 4 DEMO MANUAL DC1789A Layer 2. Bottom Layer PCB Layout dc1789afa 5 DEMO MANUAL DC1789A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER I.C., LTM2884CY LINEAR LTM2884CY#PBF Required Circuit Components 1 1 U1 Hardware/Components (For Demo Board Only) 2 1 C1 CAP., TANT 22F 25V 20% `C' AVX TAJC226M025R 3 1 C2 CAP., TANT 100F 10V 20% `C' AVX TPSC107M010R0150 4 1 J1 USB RECEPTACLE TYPE B MILL-MAX 897-43-004-90-00000 5 1 J2 USB RECEPTACLE TYPE A MILL-MAX 896-43-004-90-00000 6 3 JP1-4 0.1" SINGLE ROW HEADER, 3-PIN SAMTEC TSW-103-26-L-S 7 3 JP1-4 SHUNT SAMTEC SNT-100-BK-G 8 4 TP1-4 TESTPOINT, TURRET, 0.095 MILL-MAX 2501-2-00-80-00-00-07-0 dc1789afa 6 DEMO MANUAL DC1789A Schematic Diagram dc1789afa 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. 7 DEMO MANUAL DC1789A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright (c) 2004, Linear Technology Corporation dc1789afa 8 Linear Technology Corporation LT 0314 REV A * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2013