REG5601

® RE G5 60 1 REG5601 RE G5 60 1 18-LINE SCSI ACTIVE TERMINATOR FEATURES q COMPLIES WITH SCSI-2 SPECIFICATIONS q INTERNAL 2.9V REGULATOR q ON-CHIP TERMINATION RESISTORS q DISCONNECT ALL TERMINATION RESISTORS WITH A SINGLE LOGIC COMMAND q POWER-DOWN MODE: 150µA max q LINE CAPACITANCE: 10pF typ q CURRENT LIMIT AND THERMAL SHUTDOWN PROTECTION q 28-Lead SOIC and SSOP PACKAGES DESCRIPTION The REG5601 is an 18-line active terminator for SCSI-2 (Small Computer Systems Interface) circuitry. On-chip resistors and 2.9V regulator provide the prescribed 110Ω termination for low power dissipation and high speed data transmission. All line connections can be disconnected from the bus with a single logic control line to reduce standby power consumption. Output lines remain high impedance without power applied. Each line is individually clamped at ground to dissipate negative-going glitches. The 2.9V regulator is current-limited and thermally protected. Regulated output is available for external circuitry. The REG5601 is available in 28-lead SOIC and finepitch SSOP packages and is specified for operation over the 0°C to 70°C temperature range. Termpwr Termpwr Thermal Shutdown Current Limit Clamp 110Ω 2.9V Reg Out Switch Signal Line 1 Ground 110Ω 2.9V Signal Line 2 • • • (18 Lines) Disconnect Switch Drive International Airport Industrial Park • Mailing Address: PO Box 11400 • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706 Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 © 1994 Burr-Brown Corporation PDS-1216B Printed in U.S.A. August, 1995 SPECIFICATIONS TA = 0° C to +70°C, Termpwr = 4.75V, and Disconnect = 0V unless otherwise specified. REG5601U PARAMETERS POWER SUPPLY Termpwr Supply Voltage Termpwr Supply Current Power-Down Mode TERMINATION LINES Termination Impedance Output High Voltage Maximum Output Current Output Clamp Level Output Leakage Output Capacitance REGULATOR Regulator Output Voltage Line Regulation Load Regulation Drop-Out Voltage Short-Circuit Current Current Sink Thermal Shutdown DISCONNECT LOGIC INPUT Disconnect Threshold Threshold Hysterisis Input Current (Internal Pull-Up) TEMPERATURE RANGE Operating Storage θJL (junction to lead) CONDITIONS MIN 4.0 All Termination Lines = Open All VTERM = 0.5V Disconnect = Open (High) ∆ITERM = 5mA to 15mA Termpwr = 4V(1) VTERM = 0.5V Termpwr = 4V, VTERM = 0.5V(1) ITERM = –30mA Disconnect = Open (High), Tempwr = 0V to 5.25V Disconnect = Open (High) 107 2.65 20.5 19.4 –0.2 14 385 100 110 2.8 21.7 21 –0.05 20 10 2.9 6 20 1.0 1350 11 170 1.6 200 6 TYP MAX 5.25 25 430 150 115 22.4 22.4 0.1 400 MIN 4.0 14 385 100 107 2.65 19.8 19 –0.2 110 2.8 21.7 21 –0.05 20 10 2.9 6 20 1.0 1350 11 170 1.6 200 6 REG5601E TYP MAX 5.25 25 430 150 115.5 22.4 22.4 0.1 400 UNIT V mA mA µA Ω V mA mA V nA pF V mV mV V mA mA °C V mV µA °C °C °C/W 2.8 Termpwr = 4V to 6V IREG = 0 to 400mA All VTERM = 0.5V, ∆VREG = 100mV VREG = 0V VREG = 3.5V 450 8 3.0 20 50 1.2 1650 2.8 450 8 3.0 20 50 1.2 1650 0.8 Disconnect = 0V 0 –40 2.0 15 70 150 0.8 2.0 15 70 150 0 –40 20 20 NOTE: (1) Measurement of each termination line while the other 17 lines are held low (0.5V). CONNECTION DIAGRAM Top View Disconnect Termination Line 1 Termination Line 2 Termination Line 3 Termination Line 4 Termination Line 5 (Thermal) GND (Thermal) GND (Thermal) GND Termination Line 6 Termination Line 7 Termination Line 8 Termination Line 9 Termpwr 1 2 3 4 5 6 7 REG5601 8 9 10 11 12 13 14 21 20 19 18 17 16 15 GND (Thermal) GND (Thermal) Termination Line 13 Termination Line 12 Termination Line 11 Termination Line 10 Reg Out 28 27 26 25 24 23 22 GND Termination Line 18 Termination Line 17 Termination Line 16 Termination Line 15 Termination Line 14 GND (Thermal) ABSOLUTE MAXIMUM RATINGS SOIC SSOP Termpwr Voltage ................................................................................. +7V Signal Line Voltage ................................................................... 0V to +7V Regulator Output Current ................................................................. 1.65A Power Dissipation .............................................................................. 2.5W Operating Junction Temperature ................................... –40° C to +150°C Storage Temperature ..................................................... –40° C to +150°C PACKAGE/ORDERING INFORMATION MODEL REG5601U REG5601E PACKAGE Plastic 28-Lead SOIC Plastic 28-Lead SSOP PACKAGE DRAWING NUMBER(1) 217 324 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. ELECTROSTATIC DISCHARGE SENSITIVITY This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. NOTE: Pin 28 is electrical ground. Connect pins 7, 8, 9, 20, 21, 22 to large circuit trace for proper heat sinking. Connect to ground or leave open-circuit. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® REG5601 2 4V to 5.25V 4.7µF Tantalum + 14 Termpwr 0 = Termination On 1 = Disconnect 1 28 Disconnect Gnd T18 27 (18 Lines) T1 2 SCSI Cable Regulator 15 Output REG5601 2.9V + 4.7µF Tantalum 2.9V 4.7µF Tantalum + 4V to 5.25V 4.7µF Tantalum + 14 Termpwr 1 15 Regulator Disconnect Output REG5601 28 Gnd T18 27 (18 Lines) T1 2 0 = Termination On 1 = Disconnect To Controller Transceivers (18 Lines) To Controller Transceivers FIGURE 1. Standard SCSI Termination Application. Thermal ground (leads 7, 8, 9, 20, 21, 22). Connect to circuit ground or leave open-circuit. TJ = TA + PD θJA PACKAGE SO-28 CIRCUIT BOARD MATERIAL 1-Layer(1) 3-Layer(2) Aluminum(3) 1-Layer(1) 3-Layer(2) Aluminum(3) θJL JUNCTION TO LEAD + (°C/W) 20 20 20 20 20 20 + + + + + + θBA BOARD TO AMBIENT (°C/W) 30 21 12 36 23 13 θJA = JUNCTION TO AMBIENT (°C/W) = = = = = = 50 41 32 56 43 33 SSOP-28 NOTES: (1) Single-side layout on 0.062 inch FR4, 1 oz copper. (2) Three-layer layout on 0.062 inch FR4, 1 oz copper. (3) Aluminum 0.062 inch substrate, 0.003 insulation, one layer, 1 oz copper (Thermal Clad, Bergqueist Co.) FIGURE 2. Circuit Board Layout. The REG5601 has current limit and thermal shutdown that protect it from damage during output short-circuit or overload. The current limit is approximately 1350mA and thermal shutdown activates at a junction temperature of approximately 175°C. For good reliability, the junction temperature should not exceed 125°C. Any tendency to activate the thermal shutdown during normal operation is an indication of inadequate heat sinking and/or excessive power dissipation. Heat is dissipated primarily by conduction through the leads to circuit board traces. It is important to connect the six thermal ground leads (7, 8, 9, 20, 21, 22) to a large circuit trace—see Figure 2. Measured values of thermal resistance for various circuit board materials are shown. These are approximate values. Variations in circuit board pattern, mounting techniques, air flow, proximity to other circuit boards and heat sources will affect thermal performance. 3 A simple experiment will determine whether the actual circuit board layout is adequate (i.e., θBA is low enough) so that the maximum recommended junction temperature of the REG5601 will not be exceeded. The procedure uses the internal thermal shutdown feature of the REG5601 (at TJ ≈ 175°C) to determine when the junction is approximately 50°C above the maximum recommended junction temperature (TJ = 125°C). Operate the circuit with normal or other desired test electrical conditions. Increase the ambient temperature and determine the value at which thermal limit occurs (by sensing a sudden drop in VREG output). At this point TJ is approximately 175°C. If this occurs at an ambient temperature of more than 50°C above the system ambient temperature design goal, the TJ will not exceed 125°C under the same electrical conditions when the ambient temperature is at the system design goal value. ® REG5601