SPF MPT3 02 Plastic Fiber Optic Transmitter for MOST(R) Data Sheet Description Features The 4-pin MOST Optical Transmitter (MPT3 02) is a highly integrated CMOS IC combined with a high speed LED designed to transmit up to 25Mbit/s optical data which is biphase coded at up to 50Mbaud. Excellent solution for converting high speed data from TTL to Plastic Optical Fiber (POF) The internal peaking circuit minimizes PWD. The current through the LED will be setup by an external resistor connected to VCC. This makes it possible to control the optical output power of the LED. MPT3 02 * High speed transmitter up to 50 Mbaud * TTL Data Input (Logic to Light Function) * 650 nm for working in a low attenuation range of PMMA Fiber * High coupled power in1000 micron plastic fiber * Low cost Applications * Optical Transmitter for MOST Systems Actual design status: IC Revision package type device marking J CAI MPT3 02 Maximum Ratings Recommended Operating Conditions Parameter Symbol Min Max Unit Parameter Symbol Min Storage Temperature Range TSTG -40 100 C Supply Voltage VCC 4.75 5.25 V Junction Temperature TJ -40 100 C Operating Temperature Range (Rext =13.5 kOhm) TA -40 Soldering Temperature (>2.5 mm from case bottom t5s) TS - 235 C Power Dissipation PTOT - 300 mW Power Supply Voltage VCCMax -0.5 6.0 V Max Unit 85 C All the data in this specification refers to the operating conditions above unless otherwise stated. Optical Signal Characteristics (22.5 Mbit/s MOST Data, VCC=4.75 .. 5.25 V) Parameter Symbol Min Typ Max Unit Peak wavelength at TA=25C l Peak25 640 650 660 nm Temperature coefficient lPeak TCl - 0.16 - nm/K Peak wavelength at TA=-40..85C lPeak 630 650 670 nm Spectral bandwidth (FWHM) Delta l - 20 30 nm Average Output Power coupled into plastic fiber at TA=25C, Rext=15 kOhm [1] Popt25, O -7.4 (185) -5.2 (300) -3.6 (435) dBm (W) TCPopt [1] Average Output Power coupled into plastic fiber at TA=-40..85C, Rext=15 kOhm Popt - - 0.4 - %/K -8.6 (140) -5.2 (300) -3.1 (490) dBm (W) Average Output Power coupled into plastic fiber at TA=-40..85C, Rext=15 kOhm, over lifetime [1] Popt, lifetime -9.6 (110) -5.2 (300) -2.1 (615) dBm (W) Gain in Popt when using 13.5 KOhm instead of 15 KOhm 0.35 0.4 0.45 dB Temperature coefficient Popt Optical Rise Time (20% - 80%) tr - 4 6 ns Optical Fall Time (20% - 80%) tf - 4 6 ns Extinction Ratio re 10 11 - dB Pulse Width Variation[2] tPWV 20.9 - 24.4 ns Average Pulse Width Distortion[2] tAPWD -0.5 - 1.5 ns Notes: 1. The output power coupled into plastic fiber Popt is measured with a large area detector at the end of a short length of a fiber (about 30 cm), which is ideally coupled to the Sidelooker. This value must not be used for calculating the power budget for a fiber optic system with a long fiber because the numerical aperture of plastic fibers decreases on the first meters. Therefore the fiber seems to have a higher attenuation over the first few meters compared with the specified value. Due to the direct coupling of the fiber to the LED at the end of the short fiber UMD (uniform mode distribution) will be observed. Therefore the following section of the cable has higher losses compared with EMD (equilibrium mode distribution) 2. The electrical input signal fulfills tPWV(min) = 22.9 ns and tPWV(max) = 24.1 ns. Pulse Width Variation (tPWV ) and Average Pulse Width Distortion (tAPWD) The SPF MPT3 02 generates negative Puls Width Distortion. This means the optical output signal is shortened compared to the electrical input signal. Therefore the parameters tPWV and tAPWD do not meet the MOST Specification of Physical Layer Rev 1.0 (MOST SPL Rev. 1.0) either at the electrical input signal (SP1 in the MOST SPL Rev. 1.0) or at the optical output signal (SP2 in the MOST SPL Rev. 1.0). This characteristic is shown in the following table. Electrical Input Signal Optical Output Signal a b Parameter Symbol Min Max Mix Max Unit Remarks Pulse Width Variation tPWV 22.9 24.1 20.9 24.4 ns Average Pulse Width Distortion tAPWD 1.0 1.5 -0.5 1.5 ns Optical Output Signal according to MOST Specification of Physical Layer Rev. 1.0 Pulse Width Variation 21.1 23.1 19.1 23.4 ns -0.5 0.5 -2.0 0.5 ns tPWV Average Pulse Width Distortion tAPWD Electrical Input Signal according to MOST Specification of Physical Layer Rev. 1.0 Based on this table, the MOST System may be considered by two aspects: a) In order to meet the MOST SPL Rev 1.0 at SP2 the tPWV and tapwd at SP1 have to be longer than described in the MOST SPL Rev. 1.0. This can be achived e.g. by using OS8104 as MOST transceiver chip. b) If the MOST SPL Rev. 1.0 is met regarding tPWV and tapwd at SP1, then the output signal SP2 is systematically shortened. Within a MOST System, this characteristic can be compensated by the optical receiver which detects the signal at SP3. For this compensation, the optical receiver has to be specified in a range which is smaller than the range described in the MOST SPL Rev. 1.0. For a detailed evaluation of system behavior, see paper "OS8300 Revision J behavior on SP2 (optical output signal)" from Oasis SiliconSystems. DC Characteristics Parameter Symbol Min Typ Max Unit Low Level Input Voltage VIL -0.3 - 0.8 V High Level Input Voltage VIH 2.0 - VCC + 0.3 V Input Leakage Current (VCC=5.0V, VI=0.0V or VI=5.0V) IL - - +/- 20 A Input Capacitance CI - - 7 pF Input Resistance RI 100 - - kOhm Supply Current (Rext = 15 kOhm) ON state, biphase coded data[1] ICC - 25 35 mA Supply Current (Rext = 15 kOhm) OFF state[2] ILP2 - - 1 mA Notes: 1. The current through the LED and therefore the optical output power and overall power consumption depends on the settings of Rext. The nominal value for Rext is 15K. With Rext=30K the optical output power is about -3dB of the nominal value. Typical behaviour see Fiure below. Important: The external resistor of Rext must be within the range of 13.5K to 33K. For values of Rext out of this range functionality may not be given over the whole temperature range and the device lifetime. Using values below 13K for Rext can damage the transmitter. 2. The transmitter jumps to low power mode after TX DATA is low for max. 18s If the transmitter is in low power mode it is switched ON 5s (max.) after TX DATA starts toggling. AC Electrical Characteristics Parameter Test Conditions Symbol Min Typ Max Unit Power Supply Rejection Ratio 25 MHz Power Supply Noise PSRR - 30 - dB Power Up Time Zero - MOST Data TPU 1.0 2.5 5.0 s Power Down Time MOST Data - Zero TPD - - 18.0 s Input Rise Time tTLH - - 5 ns Input Fall Time tTHL - - 5 ns Typical Dependency of Average Output Power Popt on external Resistor Rext (22.5 MBit MOST Data/ VCC=5 V / TA=25C) Typical Output Signal Measured with fast optical receiver (Graviton SPD-1) with 15 kOhm external resistor and 22.579 Mbit/s MOST Data at TA=25C. Mechanical Design MPT3 02: CAI package (cavity as interface) Device information (Lot number etc.) is given on CAI backside by laser marking (for details see drawing marking specification). Application Circuit: Notes: 1. Place these components as close as possible to their corresponding pins of the FOT. 2. Values can change due to different light output power of the LED. 3. This is just a proposal for the Rext application. There can be used also other circuits to switch Rext from 15K to 30K Design & Layout rules * The 100nF bypass capacitors of the FOTs must be located as close as possible between the pins Vcc and GND of the FOTs. Use ceramic caps and tantalum caps with low ESR. * Also the inductor/ferrite bead (receiver) and the -3dB - control circuit (transmitter) must be placed as close as possible to the FOTs. We prefer ferrite beads (e.g. type 74279214 Wurth Elektronik) since the d.c. resistance is very low. If other inductors are used the d.c. resistor should be less than 3Ohm. * For EMC a ferrite bead should be connected to the power supply close to the transmitter and the receiver. Do not use only one ferrite bead together for receiver and transmitter! * For the ground connection a ground plane is recommended (Y-structure). That means the ground planes of the transmitter, the receiver and the shielding must be separated. The three ground planes should be connected together behind the bypass capacitors (refer to the PCB design below). This ground signal should be connected directly to the ground plane of the MOST controller (e.g. OS8104) and the power supply on the top layer and/or bottom layer and ground layer as it is indicated in the example below. * If a multi layer design is used the ground layer must have the same ground separation like shown for the top layer! * A serial resistor in the Rx/Tx data line will also reduce EMC - problems. For Rx the resistor must be placed near the receiver - for Tx the resistor must be placed near the MOST controller chip. The value depends from the distance between the FOTs and the MOST chip (< 5cm) and can be in the range of up to 150R. Higher values for the resistors will increase jitter and can therefore cause locking problems of the MOST PLL! * The Rx/Tx signals should not be routed parallel over a long distance but may be embedded with ground copper, if possible. * The GND pin and the pin of Rext (15K - resistor) of the transmitter are used for heat dissipation. Therefore there should be a good connection to the PCB - no isolation gaps! Both pins should dip into a copper area (see layout example below). Layout example The reference board from OASIS Silicon Systems follows the requirements above. The schematic is very similar to the example above, but does not include the connection to the power supply, the OS8104 or the microcontroller. The examples below for top- and bottom layer is the layout of the reference design board and shows how the layout around the optical receiver and transmitter should look like. It is strongly recommended to follow this examples in your design to get best performance! Note: 1. The buffer circuit (IC1), the connectors and jumpers in the middle to the right section of the schematic are only for use of the reference board and will not be necessary for your HW - design. Top Layer with 180 version of the pigtail: Bottom Layer (seen from the top side of the PCB): Bottom Layer: Bottom side / positions Other items * The shown circuit for the -3dB attenuation is just a proposal. Also any other circuit which can double the value of Rext is permitted. * Due to the fact that the optical average level jumps if the power control signal (/-3dB) is toggled there can occur LOCK/coding - errors at the following device for a short time. This is not very critical, since it does occur only in diagnosis mode. After a time of 10ms the device should lock again if the optical attenuation between the devices is not too high. * The Rx and Tx signals can be measured by using standard probes (>1M/<10pF). However, if the signal quality is very bad and the LOCK signal of the MOST chip is flaky connecting a passive probe to the Rx signal can cause the MOST chip to lock better or worse to the signal. This is due to the capacitance of the analog probe which is usually in the range of 8..12pF and shifts the phase and PWD of the signal. In this case an active probe with a capacitance of less than 1pF is recommended. * The reference test board which corresponds to the layout examples above is available at the Oasis Silicon System AG. Disclaimer The information herein is given to describe certain components and shall not be considered as a guarantee of characteristics. Terms of delivery and rights to technical change reserved.We hereby disclaim any and all warranties, including but not limited to warranties of non-infringement, regarding circuits, descriptions and charts stated herein. Warnings Due to technical requirements components may contain dangerous substances. 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Revision History Current Document: AV02-0985EN - January 11, 2008 Previous Version: AV01-0737EN - July 6, 2007 Page Subjects (major changes since last revision) 9 Addition of "Revision History" For product information and a complete list of distributors, please go to our web site: www.avagotech.com Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Limited in the United States and other countries. Data subject to change. Copyright (c) 2008 Avago Technologies Limited. All rights reserved. Obsoletes AV01-0737EN AV02-0985EN - January 11, 2008