TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 available features • • • • • • • • Fully Integrated 9-Channel SCSI Termination No External Components Required Maximum Allowed Current Applied at First High-Level Step 6-pF Typical Power-Down Output Capacitance Wide Vterm† (Termination Voltage) Operating Range, 3.5 V to 5.5 V TTL-Compatible Disable Feature Compatible With Active Negation Thermal Regulation PW PACKAGE (TOP VIEW) TERMPWR NC NC D0 D1 D2 D3 D4 NC GND 1 20 2 19 3 18 4 17 5 16 6 15 7 14 8 13 9 12 10 11 TERMPWR DISABLE NC D8 D7 NC D6 D5 NC GND NC – No internal connection description The TL2218-285 is a current-mode 9-channel monolithic terminator specially designed for single-ended small-computer-systems-interface (SCSI) bus termination. A user-controlled disable function is provided to reduce standby power. No impedance-matching resistors or other external components are required for its operation as a complete terminator. The device operates over a wide termination-voltage (Vterm†) range of 3.5 V to 5.5 V, offering an extra 0.5 V of operating range when compared to the minimum termination voltage of 4 V required by other integrated active terminators. The TL2218-285 functions as a current-sourcing terminator and supplies a constant output current of 23 mA into each asserted line. When a line is deasserted, the device senses the rising voltage level and begins to function as a voltage source, supplying a fixed output voltage of 2.85 V. The TL2218-285 features compatibility with active negation drivers and has a typical sink current capability of 20 mA. The TL2218-285 is able to ensure that maximum current is applied at the first high-level step. This performance means that the device should provide a first high-level step exceeding 2 V even at a 10-MHz rate. Therefore, noise margins are improved considerably above those provided by resistive terminators. A key difference between the TL2218-285 current-mode terminator and a Boulay terminator is that the TL2218-285 does not incorporate a low dropout regulator to set the output voltage to 2.85 V. In contrast with the Boulay termination concept, the accuracy of the 2.85 V is not critical with the current-mode method used in the TL2218-285 because this voltage does not determine the driver current. Therefore, the primary device specifications are not the same as with a voltage regulator but are more concerned with output current. The DISABLE terminal is TTL compatible and must be taken low to shut down the outputs. The device is normally active, even when DISABLE is left floating. In the disable mode, only the device startup circuits remain active, thereby reducing the supply current to just 500 µA. Output capacitance in the shutdown mode is typically 6 pF. The TL2218-285 has on-board thermal regulation and current limiting, thus eliminating the need for external protection circuitry. A thermal regulation circuit that is designed to provide current limiting, rather than an actual thermal shutdown, is included in the individual channels of the TL2218-285. When a system fault occurs that leads to excessive power dissipation by the terminator, the thermal regulation circuit causes a reduction in the asserted-line output current sufficient to maintain operation. This feature allows the bus to remain active during a fault condition, which permits data transfer immediately upon removal of the fault. A terminator with thermal shutdown does not allow for data transfer until sufficient cooling has occurred. Another advantage offered by the TL2218-285 is a design that does not require costly laser trimming in the manufacturing process. The TL2218-285 is characterized for operation over the virtual junction temperature range of 0°C to 125°C. † This symbol is not presently listed within EIA/JEDEC standards for letter symbols. Copyright 1995, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 8–1 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 AVAILABLE OPTIONS SURFACE MOUNT (PW)† TJ CHIP FORM (Y) 0°C to 125°C TL2218-285PWLE TL2218-285Y † The PW package is only available left-end taped and reeled. TL2218-285Y chip information This chip, when properly assembled, displays characteristics similar to the TL2218-285. Thermal compression or ultrasonic bonding may be used on the doped aluminum bonding pads. The chip may be mounted with conductive epoxy or a gold-silicon preform. BONDING PAD ASSIGNMENTS (1) (20) (19) 1, 20 TERMPWR Feedback 19 (17) (4) Active Negation Clamp DISABLE Vref Thermal Regulation (16) (5) 4 Common to All Channels 161 (6) CHIP THICKNESS: 11 MILS TYPICAL BONDING PADS: 4 × 4 MILS MINIMUM (14) (7) TJmax = 150°C TOLERANCES ARE ± 10%. ALL DIMENSIONS ARE IN MILS. (8) (10) (11) (13) 84 8–2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 D0 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 functional block diagram (each channel) 1, 20 TERMPWR Feedback DISABLE Active Negation Clamp 19 Vref 4 D0 Thermal Regulation Common to All Channels absolute maximum ratings over operating free-air temperature range (unless otherwise noted) (see Figures 1, 2, and 3)† Continuous termination voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 V Continuous output voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 5.5 V Continuous disable voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 5.5 V Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table Operating virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 55°C to 150°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 60°C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATING TABLE PACKAGE POWER RATING AT PW TA TC TL‡ T ≤ 25°C POWER RATING DERATING FACTOR ABOVE T = 25°C T = 70°C POWER RATING T = 85°C POWER RATING 430 mW T = 125°C POWER RATING 828 mW 6.62 mW/°C 530 mW 166 mW 4032 mW 32.2 mW/°C 2583 mW 2100 mW 812 mW 2475 mW 19.8 mW/°C 1584 mW 1287 mW 495 mW ‡ RθJL is the thermal resistance between the junction and device lead. To determine the virtual junction temperature (TJ) relative to the device lead temperature, the following calculations should be used: TJ = PD x RθJL + TL , where PD is the internal power dissipation of the device and TL is the device lead temperature at the point of contact to the printed wiring board. RθJL is 50.5°C/W. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 8–3 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 CASE TEMPERATURE DISSIPATION DERATING CURVE 2400 Maximum Continuous Power Dissipation – mW Maximum Continuous Power Dissipation – mW FREE-AIR TEMPERATURE DISSIPATION DERATING CURVE 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 RθJA = 151°C/W 4800 4400 4000 3600 3200 2800 2400 2000 1600 1200 RθJC = 31°C/W 800 400 0 0 25 50 75 100 125 150 25 50 TA – Free-Air Temperature – °C 75 100 125 150 TC – Case Temperature – °C Figure 1 Figure 2 Maximum Continuous Power Dissipation – mW LEAD TEMPERATURE DISSIPATION DERATING CURVE 4800 4400 4000 3600 3200 2800 2400 2000 1600 1200 800 † RθJL = 50.5°C/W 400 0 25 50 75 100 125 150 TL – Lead Temperature – °C Figure 3 † RθJL is the thermal resistance between the junction and device lead. To determine the virtual junction temperature (TJ) relative to the device lead temperature, the following calculations should be used: TJ = PD x RθJL + TL, where PD is the internal power dissipation of the device, and TL is the device lead temperature at the point of contact to the printed wiring board. RθJL is 50.5°C/W. 8–4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 recommended operating conditions MIN MAX 3.5 5.5 V High-level disable input voltage, VIH 2 0 Vterm 0.8 V Low-level disable input voltage, VIL Operating virtual junction temperature, TJ 0 125 °C MIN TYP MAX UNIT 2.5 2.85 Termination voltage UNIT V electrical characteristics, Vterm = 4.75 V, VO = 0.5 V, TJ = 25°C PARAMETER TEST CONDITIONS Output high voltage All data lines open TERMPWR supply current 9 All data lines = 0.5 V 228 DISABLE = 0 V 500 Output current – 20.5 – 23 DISABLE = 4.75 V Disable input current (see Note 1) DISABLE = 0 V Output capacitance, device disabled VO = 0 V, VO = 4 V Termination sink current, total 1 MHz mA µA – 24 1 DISABLE = 0 V Output leakage current V 600 mA µA 100 nA 6 pF 20 mA NOTE 1: When DISABLE is open or high, the terminator is active. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 8–5 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 THERMAL INFORMATION The need for smaller surface-mount packages for use on compact printed-wiring boards (PWB) causes an increasingly difficult problem in the area of thermal dissipation. In order to provide the systems designer with a better approximation of the junction temperature rise in the thin-shrink small-outline package (TSSOP), the junction-to-lead thermal resistance (RθJL) is provided along with the more typical values of junction-to-ambient and junction-to-case thermal resistances, RθJA and RθJC. RθJL is used to calculate the device junction temperature rise measured from the leads of the unit. Consequently, the junction temperature is dependent upon the board temperature at the leads, RθJL, and the internal power dissipation of the device. The board temperature is contingent upon several variables, including device packing density, thickness, material, area, and number of interconnects. The RθJL value depends on the number of leads connecting to the die-mount pad, the lead-frame alloy, area of the die, mount material, and mold compound. Since the power level at which the TSSOP can be used is highly dependent upon both the temperature rise of the PWB and the device itself, the systems designer can maximize this level by optimizing the circuit board. The junction temperature of the device can be calculated using the equation TJ = (PD × RθJL) + TL where TJ = junction temperature, PD = power dissipation, RθJL = junction-to-lead thermal resistance, and TL = board temperature at the leads of the unit. The values of thermal resistance for the TL2218-285 PW are as follows: Thermal Resistance RθJA RθJC RθJL Typical Junction Rise 151°C/W 31 °C/W 50.5°C/W TYPICAL CHARACTERISTICS Table of Graphs FIGURE 8–6 IO VO Output current vs Input voltage 4 Output voltage vs Input voltage 5 IO VO Output current vs Junction temperature 6 Output voltage vs Junction temperature 7 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL2218-285, TL2218-285Y EXCALIBUR CURRENT-MODE SCSI TERMINATOR SLVS072C – DECEMBER 1992 – REVISED OCTOBER 1995 TYPICAL CHARACTERISTICS OUTPUT CURRENT vs INPUT VOLTAGE OUTPUT VOLTAGE vs INPUT VOLTAGE 24 4 TJ = 25°C TJ = 25°C VO – Output Voltage – V VO I O – Output Current – mA 22 20 ÁÁ ÁÁ 18 16 14 3 2 1 0 3 3.5 4 4.5 VI – Input Voltage – V 5 5.5 3 3.5 Figure 4 5 5.5 Figure 5 OUTPUT CURRENT vs JUNCTION TEMPERATURE OUTPUT VOLTAGE vs JUNCTION TEMPERATURE 4 25 Vterm = 4.75 V TA = TJ Vterm = 4.75 V TA = TJ 20 VO – Output Voltage – V VO I O – Output Current – mA 4 4.5 VI – Input Voltage – V 15 ÁÁ ÁÁ 10 3.5 3 2.5 2 5 0 25 50 75 100 125 0 TJ – Junction Temperature – °C Figure 6 100 25 50 75 TJ – Junction Temperature – °C 125 Figure 7 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 8–7 8–8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 1998, Texas Instruments Incorporated