® REG1118 REG 1118 800mA Low Dropout Positive Regulator with Current Source and Sink Capability FEATURES DESCRIPTION ● SOURCES 800mA, SINKS 400mA ● 2.85V OUTPUT FOR SCSI ACTIVE NEGATION TERMINATION ● 1.3V max DROPOUT VOLTAGE AT IO = 800mA ● INTERNAL CURRENT LIMIT ● THERMAL OVERLOAD PROTECTION The REG1118-2.85 is a three-terminal voltage regulators capable of sourcing up to 800mA and sinking up to 400mA. The sinking capability is important in SCSI applications where active negation line drivers are used. The REG1118-2.85 is useful for making a 27-line Boulay terminator capable of interfacing with active negation drivers required in FAST-20 SCSI applications. The regulator has active current limits for both sink and source currents as well as internal thermal limiting. Laser trimming assures excellent output voltage accuracy. An NPN output stage allows output stage drive current to contribute to the source load current for maximum efficiency. ● SOT-223 SURFACE MOUNT PACKAGE APPLICATIONS ● SCSI-2 AND SCSI-3 DEVICES ● FAST-20 SCSI ● ACTIVE NEGATION SCSI TERMINATORS ● SUPPLY SPLITTER GROUND GENERATION REG1118 is packaged in a SOT-223 surface-mount package, suitable for reflow soldering techniques. 110Ω Signal Line 1 110Ω Signal Line 2 TERMPWR 110Ω REG1118 VIN 10µF Signal Line 3 Up To 27 Lines VOUT GND 4.7µF 110Ω Signal Line N User Supplied Resistor Network REG1118-2.85 Used to Make Active Negation SCSI Terminator InternationalAirportIndustrialPark • MailingAddress:POBox11400,Tucson,AZ85734 • StreetAddress:6730S.TucsonBlvd.,Tucson,AZ 85706 • Tel:(520)746-1111 • Twx:910-952-1111 Internet:http://www.burr-brown.com/ • FAXLine:(800)548-6133(US/CanadaOnly) • Cable:BBRCORP • Telex:066-6491 • FAX:(520)889-1510 • ImmediateProductInfo:(800)548-6132 © 1996 Burr-Brown Corporation PDS-1352B Printed in U.S.A. January, 1997 SPECIFICATIONS At TA = 0°C to 70°C, TERMPWR = +5V, unless otherwise noted. REG1118-2.85 PARAMETER CONDITIONS MIN TYP MAX UNITS No Load, TA = 25°C All Operating Conditions(1) 2.82 2.79 2.85 2.85 2.88 2.91 V V IO = 0, VIN = 4.75V to 6V 0.3 4 mV IO = 0 to 800mA IO = –400 to 0mA 2 25 25 60 mV mV TA = 25°C IO = 100mA IO = 800mA 0.8 1.1 1.1 1.3 V V VOUT = 3.7V 1450 –750 –400 mA mA 7 mA OUTPUT VOLTAGE LINE REGULATION(2) LOAD REGULATION(2) DROPOUT VOLTAGE(3) CURRENT LIMIT Positive (ISC+)(4) Negative (ISC–) TA = 25°C 800 QUIESCENT CURRENT RIPPLE REJECTION IO = 0 3 TA = 25°C f = 120Hz, VIN – VOUT = 2V, VRIPPLE = 0.5Vp-p 56 dB TA = +125°C, 1000Hr 0.2 % 150 140 °C °C LONG-TERM STABILITY THERMAL SHUTDOWN Junction Temperature Shutdown Junction Temperature Reset THERMAL RESISTANCE Specified Junction Temperature Range Operating Junction Temperature Range Storage Range Thermal Resistance θJC 0 0 –55 (Junction-to-Case at Tab) 70 125 125 °C °C °C °C/W 15 NOTES: (1) All operating conditions include the combined effects of load current, input voltage, and temperature over each parameter’s full specified range. (2) Load and line regulation are tested at a constant junction temperature by low duty cycle testing. (3) Dropout voltage is defined as the minimum input-to-output voltage that produces a 1% decrease in output voltage. (4) VOUT to ground through 1Ω. ABSOLUTE MAXIMUM RATINGS CONNECTION DIAGRAM Input Voltage .......................................................................................... 7V Output Voltage ........................................................... –0.2V to (V+) +0.5V Short-Circuit Duration .................................................................. Indefinite Operating Junction Temperature Range ............................. 0°C to +125°C Storage Temperature Range .......................................... –55°C to +125°C Lead Temperature (soldering, 10s)(1) ............................................. +300°C Front View SOT-223 Tab is connected to Ground NOTE: (1) See “Soldering Methods.” PACKAGE INFORMATION PRODUCT REG1118-2.85 PACKAGE PACKAGE DRAWING NUMBER(1) SOT-223 311 VOUT Ground VIN Plastic SOT-223 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ELECTROSTATIC DISCHARGE SENSITIVITY ORDERING INFORMATION PRODUCT(1) REG1118-2.85 PART MARKING PACKAGE BB11182 SOT-223 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: (1) Available in Tape and Reel, add –TR to Model Number. ® REG1118 2 TYPICAL PERFORMANCE CURVE At TA = 25°C, TERMPWR = +5V, unless otherwise specified. LINE TRANSIENT RESPONSE Input Voltage Deviation (V) Sourcing 800mA 0.5 0 –0.5 1 0 –1 CIN = 2.2µF COUT = 1µF Sinking 400mA 0.2 0 Output Voltage Deviation (V) Output Voltage Deviation (V) Load Current (A) LOAD TRANSIENT RESPONSE –0.2 4.7µF || 0.1µF (Tantalum) (Ceramic) 10µF || 0.1µF (Tantalum) (Ceramic) 0 25 50 75 100 125 150 175 200 0.1 0 –0.1 225 250 0 0.25 0.5 0.75 Time (µs) 1 1.25 1.5 1.75 2 2.25 2.5 Time (ms) SHORT-CIRCUIT CURRENT vs TEMPERATURE QUIESCENT CURRENT vs TEMPERATURE 1.8 5 Quiescent Current (mA) 1.4 1.2 1 0.8 0.6 4 3 Sink 2 0.4 –10 0 10 20 30 40 50 60 70 80 –10 90 0 10 20 30 40 50 60 70 80 90 Temperature (°C) Temperature (°C) DROPOUT VOLTAGE vs TEMPERATURE 1.3 1.2 IOUT = 800mA Dropout Voltage (V) Short-Circuit Current mA Source 1.6 1.1 1 0.9 0.8 0.7 IOUT = 100mA 0.6 –10 0 10 20 30 40 50 60 70 80 90 Temperature (°C) ® 3 REG1118 APPLICATIONS INFORMATION ambient temperature above that expected in normal operation until the device’s thermal shutdown is activated. If this occurs at more than 40°C above the maximum expected ambient temperature, then the TJ will be less than 125°C during normal operation. Figure 1 shows the basic hookup diagram for the REG1118. An output capacitor is required for proper operation and to improve high frequency load regulation. A high quality capacitor should be used to assure that the ESR (effective series resistance) is less than 0.5Ω. A capacitor of at least 1µF is recommended. Increasing COUT improves output voltage deviation, see the typical curve “Load Transient Response.” It is suggested that the input be decoupled with 10µF low ESR capacitor. VIN VO REG1118 10µF SOLDERING METHODS The REG1118 package is suitable for infrared reflow and vapor-phase reflow soldering techniques. The high rate of temperature change that occurs with wave soldering, or hand soldering can damage the REG1118. Total Area: 50 x 50mm 4.7µF 35 x 17 mm FIGURE 1. Basic Connections. 16 x 10 mm THERMAL CONSIDERATIONS The REG1118 has current limit and thermal shutdown circuits that protect it from overload. The thermal shutdown activates at approximately TJ = 150°C. For continuous operation, however, the junction temperature should not be allowed to exceed 125°C. Any tendency to activate the thermal shutdown in normal use is an indication of an inadequate heat sink or excessive power dissipation. The power dissipation is equal to: Without back-side copper: θJA ≈ 59°C/W With solid back-side copper: θJA ≈ 49°C/W FIGURE 2. Circuit Board Layout Example. PD = (VIN – VOUT) IOUT TOPSIDE(1) COPPER AREA BACKSIDE COPPER AREA 2500mm2 2500mm2 2500mm2 46°C/W 2500mm2 1250mm2 2500mm2 47°C/W 2500mm2 950mm2 2500mm2 49°C/W 2500mm2 2500mm2 0 51°C/W 2500mm2 1800mm2 0 53°C/W 1600mm2 600mm2 1600mm2 55°C/W 2500mm2 1250mm2 0 58°C/W 2500mm2 915mm2 0 59°C/W 1600mm2 600mm2 0 67°C/W 900mm2 340mm2 900mm2 72°C/W 900mm2 340mm2 0 85°C/W TOTAL PC BOARD AREA The junction temperature can be calculated by: TJ = TA + PD (θJA) where TA is the ambient temperature, and θJA is the junction-to-ambient thermal resistance The REG1118 derives heat sinking from conduction through its copper leads, especially the large mounting tab. These must be soldered to a circuit board with a substantial amount of copper remaining (see Figure 2). Circuit board traces connecting to the tab and the leads should be made as large as practical. Other nearby circuit traces, including those on the back side of the circuit board, help conduct heat away from the device, even though they are not electrically connected. Make all nearby copper traces as wide as possible and leave only narrow gaps between traces. In addition, multiple contacts to internal power and ground planes increase heat sinking with minimal increase in circuit board area. THERMAL RESISTANCE JUNCTION-TO-AMBIENT NOTE: (1) Tab is attached to the topside copper. TABLE I. INSPEC Abstract Number: B91007604, C91012627 Kelly, E.G. “Thermal Characteristics of Surface 5WK9Ω Packages.” The Proceedings of SMTCON. Surface Mount Technology Conference and Exposition: Competitive Surface Mount Technology, April 3-6, 1990, Atlantic City, NJ, USA. Abstract Publisher: IC Manage, 1990, Chicago, IL, USA. Table I shows approximate values of θJA for various circuit board and copper areas. Nearby heat dissipating components, circuit board mounting conditions and ventilation can dramatically affect the actual θJA. A simple experiment will determine whether the maximum recommended junction temperature is exceeded in an actual circuit board and mounting configuration: Increase the ® REG1118 16 x 10 mm 4 TERMPWR 5V TERMPWR 2.85V 110Ω 110Ω REG1118-2.85 10µF 5V 1N5817 1N5817 2.85V REG1118-2.85 4.7µF 10µF 4.7µF (Up to 27 Lines) 110Ω 110Ω FIGURE 3. SCSI Active Termination Configuration. 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. ® 5 REG1118