TL-SCSI285 FIXED-VOLTAGE REGULATORS FOR SCSI ACTIVE TERMINATION SLVS065F – NOVEMBER 1991 – REVISED JULY 1999 D D D D D D D D D PW PACKAGE (TOP VIEW) Fully Matches Parameters for SCSI Alternative 2 Active Termination Fixed 2.85-V Output ±1% Maximum Output Tolerance at TJ = 25°C 0.7-V Maximum Dropout Voltage 620-mA Output Current ±2% Absolute Output Variation Internal Overcurrent-Limiting Circuitry Internal Thermal-Overload Protection Internal Overvoltage Protection HEAT SINK GND INPUT HEAT SINK description 1 20 2 19 3 18 4 17 5 16 6 15 7 14 8 13 9 12 10 11 HEAT SINK GND OUTPUT HEAT SINK HEAT SINK – These terminals have an internal resistive connection to ground and should be grounded or electrically isolated. The TL-SCSI285 is a low-dropout (0.7-V) fixed-voltage regulator specifically designed for small computer systems interface (SCSI) alternative 2 active signal termination. The TL-SCSI285 0.7-V maximum dropout ensures compatibility with existing SCSI systems, while providing a wide TERMPWR voltage range. At the same time, the ±1% initial tolerance on its 2.85-V output voltage ensures a tighter line-driver current tolerance, thereby increasing the system noise margin. KC PACKAGE (TOP VIEW) OUTPUT GND INPUT The GND terminal is in electrical contact with the mounting base. The fixed 2.85-V output voltage of the TL-SCSI285 supports the SCSI alternative 2 termination standard, while reducing system power consumption. The 0.7-V maximum dropout voltage brings increased TERMPWR isolation, making the device ideal for battery-powered systems. The TL-SCSI285, with internal current limiting, overvoltage protection, ESD protection, and thermal protection, offers designers enhanced system protection and reliability. When configured as a SCSI active terminator, the TL-SCSI285 low-dropout regulator eliminates the 220-Ω and the 330-Ω resistors required for each transmission line with a passive termination scheme, reducing significantly the continuous system power drain. When placed in series with 110-Ω resistors, the device matches the impedance level of the transmission cable and eliminates reflections. The TL-SCSI285 is characterized for operation over the virtual junction temperature range of 0°C to 125°C. AVAILABLE OPTIONS PACKAGED DEVICES TJ PLASTIC POWER (KC) SURFACE MOUNT (PW) 0°C to 125°C TL-SCSI285KC TL-SCSI285PWR CHIP FORM (Y) TL-SCSI285Y The PW package is only available taped and reeled. Chip forms are tested at 25°C. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 1999, 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 1 TL-SCSI285 FIXED-VOLTAGE REGULATORS FOR SCSI ACTIVE TERMINATION SLVS065F – NOVEMBER 1991 – REVISED JULY 1999 absolute maximum ratings over operating virtual junction temperature range (unless otherwise noted)† Continuous input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 V Operating virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C Package thermal impedance, θJA (see Notes 1 and 2): KC package . . . . . . . . . . . . . . . . . . . . . . . . . . . 22°C/W PW package . . . . . . . . . . . . . . . . . . . . . . . . . . . 83°C/W Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: KC or PW package . . . . . . . . . . . . . 260°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°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. NOTES: 1. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can impact reliability. Due to variations in individual device electrical characteristics and thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated dissipation. 2. The package thermal impedance is calculated in accordance with JESD 51, except for through-hole packages, which use a trace length of zero. recommended operating conditions TL-SCSI285 Input voltage, VI MIN MAX 3.55 5.5 KC package 0 620 PW package 0 500 0 125 TJ = 25°C TJ = 0°C to 125°C Input voltage, VI Output current, current IO Operating virtual junction temperature range, TJ UNIT V V mA °C electrical characteristics, VI = 4.5 V, IO = 500 mA, TJ = 25°C (unless otherwise noted) Output voltage Input regulation Ripple rejection IO = 20 mA to 500 mA, IO = 500 mA to 620 mA, VI = 3.55 V to 5.5 V, VI = 3.65 V to 5.5 V, VI = 3.55 V to 5.5 V f = 120 Hz, Vripple = 1 VO(PP) TJ = 25°C TJ = 0 to 125°C MIN TYP MAX 2.82 2.85 2.88 2.79 2.91 5 Output regulation IO = 20 mA to 620 mA IO = 20 mA to 500 mA Output noise voltage f = 10 Hz to 100 kHz Dropout voltage IO = 500 mA IO = 620 mA Bias current TL-SCSI285KC TEST CONDITIONS‡ PARAMETER 15 –62 5 30 5 30 0.8 IO = 500 mA, equivalent 18 lines asserted (8-bit) IO = 620 mA mV mV µV 0.7 2 V dB 500 IO = 0 IO = 27 mA, equivalent 1 line asserted UNIT V 5 3 6 26 49 mA 37 62 ‡ Pulse-testing techniques are used to maintain the virtual junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately. All characteristics are measured with a 0.1-µF capacitor across the input and a 22.0-µF tantalum capacitor with equivalent series resistance of 1.5 Ω on the output. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TL-SCSI285 FIXED-VOLTAGE REGULATORS FOR SCSI ACTIVE TERMINATION SLVS065F – NOVEMBER 1991 – REVISED JULY 1999 electrical characteristics, VI = 4.5 V, IO = 500 mA, TJ = 25°C (unless otherwise noted) Output voltage IO = 20 mA to 500 mA mA, VI = 3.55 3 55 V to 5.5 55V Input regulation VI = 3.55 V to 5.5 V f = 120 Hz, Vripple = 1 VO(PP) Ripple rejection Output regulation Output noise voltage TL-SCSI285PW TEST CONDITIONS† PARAMETER TJ = 25°C TJ = 0 to 125°C MIN TYP MAX 2.82 2.85 2.88 2.79 2.91 5 15 –62 IO = 20 mA to 500 mA f = 10 Hz to 100 kHz 5 IO = 500 mA IO = 0 Bias current IO = 27 mA, equivalent 1 line asserted IO = 500 mA, equivalent 18 lines asserted (8-bit) V mV dB 30 mV µV 500 Dropout voltage UNIT 0.7 2 V 5 3 6 26 49 mA † Pulse-testing techniques are used to maintain the virtual junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately. All characteristics are measured with a 0.1-µF capacitor across the input and a 22.0-µF tantalum capacitor with equivalent series resistance of 1.5 Ω on the output. electrical characteristics, VI = 4.5 V, IO = 500 mA, TJ = 25°C TEST CONDITIONS† PARAMETER Output voltage IO = 20 mA to 500 mA, VI = 3.55 V to 5.5 V VI = 3.55 V to 5.5 V Input regulation Ripple rejection f = 120 Hz, Vripple = 1 VO(PP) Output regulation IO = 20 mA to 620 mA IO = 20 mA to 500 mA Output noise voltage f = 10 Hz to 100 kHz Bias current TL-SCSI285Y MIN TYP 2.85 UNIT V 5 mV –62 dB 5 5 500 IO = 0 IO = 27 mA, equivalent 1 line asserted MAX mV µV 2 3 IO = 500 mA, equivalent 18 lines asserted (8-bit) IO = 620 mA 26 mA 37 † Pulse-testing techniques are used to maintain the virtual junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately. All characteristics are measured with a 0.1-µF capacitor across the input and a 22.0-µF tantalum capacitor with equivalent series resistance of 1.5 Ω on the output. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 TL-SCSI285 FIXED-VOLTAGE REGULATORS FOR SCSI ACTIVE TERMINATION SLVS065F – NOVEMBER 1991 – REVISED JULY 1999 APPLICATION INFORMATION Connector TERMPWR 1N5817 5-V Logic Supply 110 Ω 1% TL-SCSI285 INPUT OUTPUT GND DB(0) DB(1) 0.1 µF 0.1 µF Ceramic + 22 µF Tantalum Figure 1. Typical Application Schematic 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 ATN BSY ACK RST MSG SEL C/D REQ I/O TL-SCSI285 FIXED-VOLTAGE REGULATORS FOR SCSI ACTIVE TERMINATION SLVS065F – NOVEMBER 1991 – REVISED JULY 1999 COMPENSATION CAPACITOR SELECTION INFORMATION The TL-SCSI285 is a low-dropout regulator. This means that the capacitance loading is important to the performance of the regulator because it is a vital part of the control loop. The capacitor value and the equivalent series resistance (ESR) both affect the control loop and must be defined for the load range and the temperature range. Figures 2 and 3 can be used to establish the capacitance value and ESR range for best regulator performance. ESR OF OUTPUT CAPACITOR vs LOAD CURRENT 3 2.6 2.4 0.04 Not Recommended Potential Instability 0.03 2.2 2 ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇÇ 1.6 1.4 1.2 400 µF 0.02 200 µF 0.015 1 Min ESR Boundary 0.8 0.6 0.4 100 µF 0.01 22 µF 0.005 0.2 0 0 0.1 0.2 0.4 0.3 0.5 10 µF 0 0 0.5 Load Voltage 1 1.5 2 2.5 3 3.5 4 4.5 5 1/ESR IL – Load Current – A Applied Load Current 1000 µF Region of Best Stability 0.025 Max ESR Boundary 1.8 ÇÇÇ ÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ ÇÇÇÇÇÇÇÇÇÇÇÇÇ Not Recommended Potential Instability Recommended Min ESR 0.035 CL ESR – Equivalent Series Resistance – Ω ÇÇ ÇÇ CL = 22.0 µF CI = 0.1 µF TJ = 25°C 2.8 STABILITY vs ESR Figure 3 ∆ IL ∆ VL Figure 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 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. 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