GS1508-CKAE3

GS1508 HD-LINX™ HDTV Cable Driver Features • • • • • • • • • SMPTE 292M compliant Dual cable driving outputs optimized for driving data up to 1.485Gb/s ±7% tolerance output >17dB output return loss Minimum external components Seamless interface with the HD-LINX™ family of products Low-power Standard packaging Pb-free and Green Description The GS1508 is a first generation very high-speed bipolar integrated circuit designed to drive two 75Ω co-axial cables. The GS1508 is a SMPTE 292M compliant cable driver that directly interfaces with other Gennum HDTV devices and can also be used as a general purpose high-speed cable driver. The GS1508 features two complementary outputs, with amplitudes controlled within a precise ±7% variation. The output amplitude can be varied by adjusting the RSET resistor value. The serial inputs can be AC-coupled. The GS1508 is a low-power device that does not require external pull-down resistors. The GS1508 is packaged in an 8-pin SOIC, and operates from a single 5V power supply. Applicatons • 1.485Gb/s HDTV Serial Digital Receiver Interfaces for: Routers, Distribution Amplifiers, Switchers, and other transmitting equipment Bandgap Reference and Biasing Circuit RSET SDI SDI Input Differential Pair Output Stage and Control SDO SDO Patent Pending Figure A: Block Diagram GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 www.gennum.com 1 of 14 1. Pin Out 1.1 Pin Assignment SDI SDI VEE RSET 1 8 SDO SDO GND VCC 2 GS1508 7 3 (top 6 view) 4 5 Figure 1-1: Pin Assignment 1.2 Pin Descriptions Table 1-1: Pin Descriptions Pin Number 1, 2 3 4 5 6 7, 8 Symbol SDI, SDI VEE RSET VCC GND SDO, SDO Type Input Power Input Power Power Output Description Serial data inputs (non-inverting and inverting). Most negative supply voltage. Output amplitude control resistor. Most positive supply voltage. Not connected internally. Connect to Ground. Used for isolation. Serial data outputs (non-inverting and inverting). GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 2 of 14 2. Electrical Characteristics 2.1 Absolute Maximum Ratings Table 2-1: Absolute Maximum Ratings TA = 25°C unless otherwise indicated Parameter Supply Voltage Input Voltage Range (any input) Operating Temperature Range Storage Temperature Power Dissipation Lead Temperature (soldering, 10 sec) Input ESD Voltage Value 5.5V -0.3 to (VCC +0.3)V 0°C to 70°C -65°C to +150°C 300mW 260°C 2000V 2.2 DC Electrical Characteristics Table 2-2: DC Electrical Characteristics VCC = 5V, TA = 0°C to 70°C unless otherwise shown. Specifications assume 800mV output amplitude level settings into end terminated 75Ω transmission lines. Data Rate = 1485Mb/s unless otherwise shown. Parameter Supply Voltage System Power Consumption Supply Current Common Mode Input Voltage Range Common Mode Output Voltage Range Condition — Driving two 75Ω cables — — Symbol VCC PD IS VCM,IN Min 4.75 — — 2.5+(VDIFF/2) Typ 5.00 215 43 — Max 5.25 265 54 VCC-(VDIFF/2) Units V mW mA V Notes — — — — Test Level 1 1 1 2 — VCM,OUT — VCC-VOUT — V — 2 GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 3 of 14 2.3 AC Electrical Characteristics Table 2-3: AC Electrical Characteristics VCC = 5V, TA = 0°C to 70°C unless otherwise shown. Specifications assume 800mV output amplitude level settings into end terminated 75Ω transmission lines. Data Rate = 1485Mb/s unless otherwise shown. Parameter Serial Digital Rate Additive Jitter Differential Input Differential Output Output Rise/Fall Times Mismatch in Output Rise/Fall Times Overshoot Duty Cycle Distortion Output Return Loss NOTES: Condition — 1485Mb/s — — (20% to 80%) — Symbol — — Min DC — 150 750 — Typ 1485 5 — 800 120 15 Max — — 800 850 250 30 Units Mb/s psRMS mV mV ps ps Notes — 1 diff p-p p-p 2 — Test Level 1 3 2 1 1 4 — — — — 5MHz to 1485MHz — — — — — — 1 15 17 8 30 — % ps dB — — 2 4 1 4 1. RMS additive jitter measured using Pseudo Random bit sequence (223 - 1). 2. Measured with Gennum Evaluation Board (EB1508). Test Levels: 1. 2. 3. 4. 100% tested at 25°C. Guaranteed by design. Correlated value. Tested with EB1508. GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 4 of 14 3. Detailed Description 3.1 Input Interfacing SDI/SDI are high-impedance differential inputs (see Figure 4-1 for equivalent input circuit). Several conditions must be observed when interfacing to these inputs: 1. The differential input signal amplitude must be between 150 and 800mVpp. 2. The common mode voltage range must be as specified in the DC Electrical Characteristics table. For a 400mV input from the GS1504 HD cable equalizer, this corresponds to a common mode voltage range of between 2.7V and 4.8V. 3. For input trace lengths longer than approximately 1cm, the inputs should be terminated as shown in the Typical Application Circuit. The GS1508 inputs are self biased, allowing for simple AC-coupling to the device. For serial digital HDTV, a minimum capacitor value of 4.7μF should be used to allow coupling of pathological test signals. A tantalum capacitor is recommended. 3.2 Output Interfacing The GS1508 outputs are current-mode, and will drive 800mV into a 75Ω load. These outputs are protected from accidental static damage with internal static protection diodes. The SMPTE 292M standard requires that the output of a cable driver have a source impedance of 75Ω and a return loss of at least 15dB between 5MHz and 1.485GHz. In order for an HD SDI output circuit using the GS1508 to meet this specification, the output circuit shown in the Typical Application Circuit is recommended. The values of LCOMP and CCOMP will vary depending on PCB layout, but typical values are 12nH and 0.5pF respectively. The small value of CCOMP can be easily swamped by parasitic PCB capacitance, so it is recommended that the ground plane be removed under the GS1508 output circuitry (see the Application Information section in this data sheet for further details). A 4.7μF capacitor is used for AC-coupling the output of the GS1508. This value is chosen to ensure that pathological signals can be coupled without a significant DC component occurring. GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 5 of 14 Figure 3-1: Output Optimized for Waveform Symmetry, L=8.2nH, R=75Ω (Typical ORL=13.5dB) Figure 3-2: Output Optimized for Return Loss, L=12nH, C=0.5pF, R=75Ω (Typical ORL=18dB) Figure 3-1 and Figure 3-2 show the eye diagram of the GS1508 output for two different output compensation conditions. Figure 3-2 shows the GS1508 output optimized for wideband return loss of 18dB. Figure 3-1 shows the GS1508 output optimized for output waveform symmetry. In this case, the output may not exhibit a return loss of 15dB. When measuring return loss at the GS1508 output, it is necessary to take the measurement for both a logic HIGH and a logic LOW output condition. This is because the output protection diodes act as varactors (voltage controlled capacitor), as shown in Figure 3-3. Consequently, the output capacitance of the GS1508 is dependent on the logic state of the output. GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 6 of 14 GS1508 SDO SDO Figure 3-3: Static Protection Diodes 3.3 Output Return Loss Measurement To perform a practical return loss measurement, it is necessary to force the GS1508 output to a DC high or low condition. The actual measured return loss will be based on the outputs being static at VCC or VCC-1.6V. Under normal operating conditions, the outputs of the GS1508 swing between VCC-0.4V and VCC-1.2V, so the measured value of return loss will not represent the actual operating return loss. A simple method of calculating the values of actual operating return loss is to interpolate the two return loss measurements. With this method, the values of return loss are estimated at VCC-0.4V and VCC-1.2V based on the measurements at VCC and VCC-1.6V. The two values of return loss (high and low) will typically differ by several decibels. If the measured return loss is RH for logic high and RL for logic low, then the two values can be interpolated as follows: RIH = RH - (RH-RL)/4 and RIL = RL + (RH-RL)/4 Where RIH is the interpolated logic high value and RIL is the interpolated logic low value. For example: if RH = -18dB and RL = -14dB; the interpolated values are RIH = -17dB and RIL = -15dB. 3.4 Output Amplitude Adjustment The output amplitude of the GS1508 can be adjusted by changing the value of the RSET resistor as shown in Figure 3-4 and Table 3-1. For an 800mVp-p output with a nominal ±7% tolerance, a value of 53.6% is required. A ±1% SMT resistor should be used. The RSET resistor is part of the high-speed output circuit of the GS1508. The resistor should be placed as close as possible to the RSET pin. In addition, PCB capacitance should be minimized at this node by removing the PCB groundplane beneath the RSET resistor and the RSET pin. GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 7 of 14 1.000 0.800 Output Swing 0.600 0.400 0.200 0.000 0.0000 0.0050 0.0100 0.0150 0.0200 0.0250 1 / RSET (mho) Figure 3-4: GS1508 Output Amplitude vs. 1/RSET Table 3-1: RSET vs. VOUT RSET (Ω) 500.0 150.0 75.0 53.6 43.2 1/RSET 0.0020 0.0067 0.0133 0.0187 0.0231 Output Swing 0.095 0.298 0.575 0.785 0.937 NOTE: For reliable operation of the GS1508 over the full temperature range, do not use an RSET value below 49.9Ω. GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 8 of 14 4. Input/Output Circuits VCC 5k SDI SDI 20k Figure 4-1: SDI/SDI SDO SDO + RSET Figure 4-2: SDO/SDO GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 9 of 14 5. Application Information 5.1 Typical Application Circuit VCC 100n PECL INPUT 75 75 CCOMP LCOMP 75 4µ7 + 75 VCC LCOMP CCOMP All resistors in Ohms and all capacitors in Farads unless otherwise shown. 1 2 3 SDI SDI GS1508 VEE RSET SDO SDO GND VCC 8 7 6 5 OUT + 4µ7 Z0 Z0 4 OUT 1n 53.6 0µ1 Figure 5-1: GS1508 Typical Application Circuit Table 5-1: Typical Application Circuit Component Values Component RSET ZO LCOMP CCOMP Value 53.6 50Ω 12nH 0.5pF For 800mV output Comments For 50Ω PCB trace impedance Typical value. Component value will vary depending on PCB layout Typical value. Component value will vary depending on PCB layout GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 10 of 14 5.2 PCB Layout Special attention must be paid to component layout when designing serial digital interfaces for HDTV. Figure 5-3 through Figure 5-6 show the artwork for a four-layer printed circuit evaluation board for the GS1508. The schematic is shown in Figure 5-2. An FR-4 dielectric can be used, however, controlled impedance transmission lines are required for PCB traces longer than approximately 1cm. Note the following PCB artwork features used to optimize performance: • • • • PCB trace width for HD rate signals is closely matched to SMT component width to minimize reflections due to change in trace impedance The PCB ground plane is removed under the GS1508 output components to minimize parasitic capacitance The PCB ground plane is removed under the GS1508 RSET pin and resistor to minimize parasitic capacitance Input and output BNC connectors are surface-mounted in-line to eliminate a transmission line stub caused by a BNC mounting via high-speed traces, which are curved to minimize impedance changes due to change of PCB trace width 5.3 GS1508 Evaluation Board 5.3.1 EB1508 PCB Schematic VCC TP1 C1 1µ C2 100n C3 1n TP2 VCC C16 1n R13 50 R8 75 U2 SDI SDO SDI SDO VEE GND RSET VCC R12 50 C14 J7 EDGEMNT_BNC J6 1µ C13 C10 100n R7 75 L2 10n R9 75 C17 0p5 L3 10n C11 4µ7 C12 4µ7 J4 EDGEMNT_BNC J5 EDGEMNT_BNC EDGEMNT_BNC 1µ R11 53.6 All resistors in Ohms and all capacitors in Farads unless otherwise shown. C15 10n VCC R10 75 C18 0p5 Figure 5-2: Schematic Diagram for the GS1508 Evaluation Board GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 11 of 14 5.3.2 EB-1508 PCB Layout Figure 5-3: Top Layer Figure 5-4: Ground Layer Figure 5-5: Power Layer Figure 5-6: Bottom Layer GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 12 of 14 6. Package and Ordering Information 6.1 Package Dimensions SYMBOL D X 8 SOIC Min. 0.054 0.004 0.014 0.189 0.150 Max. 0.068 0.0098 0.019 A E 0.010 Gauge Plane A1 B D E H e C L X q1 q2 Pin 1 ID Mark q2 e B DETAIL “A” Seating Plane L 0.015 ±0.004 x 45° DETAIL “A” 0.196 0.157 0.244 0.229 0.050 BSC 0.0075 0.016 0.0098 0.034 0.0215 REF 0° 8° 7° BSC C A A1 q1 NOTES: 1. All dimensions in inches unless otherwise stated. 2. Lead coplanarity should be 0 to 0.004” max. 3. Package surface finishing: VDI 24~27 (dual). Package surface finishing: VDI 13~15 (16L SOIC[NB] matrix). 4. All dimensions exclude mold flashes. 5. The lead width (B) to be determined at 0.0075” from the lead tip. Figure 6-1: Package Dimensions 6.2 Ordering Information Part Number GS1508-CKAE3 GS1508-CTAE3 Package 8-pin SOIC 8-pin SOIC, tape & reel (250pc) Temperature 0°C to 70°C 0°C to 70°C Pb-free and Green Yes Yes GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 13 of 14 Revision History Version 6 ECR 154757 PCN — Date August 2010 Changes and/or Modifications Converted document to new format. Corrected Figure 6-1: Package Dimensions and Ordering Information. DOCUMENT IDENTIFICATION CAUTION ELECTROSTATIC SENSITIVE DEVICES DO NOT OPEN PACKAGES OR HANDLE EXCEPT AT A STATIC-FREE WORKSTATION DATA SHEET The product is in production. Gennum reserves the right to make changes to the product at any time without notice to improve reliability, function or design, in order to provide the best product possible. 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Sinyi District, Taipei City 11502 Taiwan R.O.C. Phone: (886) 2-8732-8879 Fax: (886) 2-8732-8870 E-mail: gennum-taiwan@gennum.com Gennum Corporation assumes no liability for any errors or omissions in this document, or for the use of the circuits or devices described herein. The sale of the circuit or device described herein does not imply any patent license, and Gennum makes no representation that the circuit or device is free from patent infringement. All other trademarks mentioned are the properties of their respective owners. GENNUM and the Gennum logo are registered trademarks of Gennum Corporation. © Copyright 1998 Gennum Corporation. All rights reserved. www.gennum.com GS1508 HD-LINX™ HDTV Cable Driver Data Sheet 9500 - 6 August 2010 14 of 14 14