www.fairchildsemi.com FAN1581 5A Adjustable/Fixed Ultra Low Dropout Linear Regulator Features Description • • • • • • • • The FAN1581, FAN1581-1.2, FAN1581-1.5, and FAN15812.5 are ultra-low dropout regulators with 5A output current capability. These devices have been optimized for low voltage applications including VTT bus termination, where transient response and minimum input voltage are critical. The FAN1581 is ideal for low voltage microprocessor applications requiring a regulated output from 1.3V to 5.7V with a power input supply of 1.75V to 6.5V. The FAN1581-1.5 offers fixed 1.5V with 5A current capabilities for GTL+ bus VTT termination. Additionally, the FAN1581-1.2 offers fixed 1.2V output for CPU Bus termination. The FAN1581-2.5 offers fixed 2.5V with 5A current capability for logic IC operation and processors while minimizing the overall power dissipation. Ultra Low dropout voltage, 0.4V typical at 5A 1.2V Versions available for GTL termination Remote sense operation Fast transient response Load regulation: 0.05% typical 0.5% typical initial accuracy On-chip thermal limiting TO-263, TO-252 and TO-220 packages Applications • • • • • • Support of GTL+ bus supply Low voltage logic supply Embedded Processor supplies Split plane regulator 2.5V, and 1.8V Logic Families DDR Termination Supply Current limit ensures controlled short-circuit current. On-chip thermal limiting provides protection against any combination of overload and ambient temperature that would create excessive junction temperatures. The FAN1581 series regulators are available in the 5-pin TO-263, TO-252 and TO-220 packages. Typical Applications VIN = 3.3V + 10µF VIN = 3.3V + 10µF VIN + + + Adj 1µF 124Ω 22µF VIN = 5.75V + 10µF 86.6Ω + 10µF FAN1581-1.2 VOUT VCNTL VCNTL = 5V + 1µF 1µF VSENSE Gnd VSENSE 5V at 5A VCNTL + VIN VIN FAN1581 VOUT VCNTL = 12V VIN = 3.3V 22µF 2.1V at 5A VCNTL VCNTL = 5V 2.5V at 5A + GND 1µF FAN1581 VOUT VSENSE FAN1581–2.5 VOUT VCNTL VCNTL = 5V VSENSE VIN Adj + 124Ω 22µF 374Ω 1.2V at 5A 22µF Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation. REV. 1.2.0 11/6/03 FAN1581 PRODUCT SPECIFICATION Pin Assignments FAN1581D FAN1581D-1.2, -1.5, -2.5 FRONT VIEW FRONT VIEW FRONT VIEW FRONT VIEW 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 S ADJ OUT CNTL IN S ADJ OUT CNTL IN S GND OUT CNTL IN 5-Lead Plastic TO-263 ΘJC=3°C/W* Tab is out. FRONT VIEW 1 2 3 4 5 CNTL IN FAN1581M S ADJ OUT FAN1581M-1.2, -1.5, -2.5 S GND OUT CNTL IN FAN1581T 5-Lead TO-220 ΘJC=3°C/W* Tab is VOUT. 5-Lead Plastic TO-252 DPAK ΘJC=3°C/W* Tab is out. *With package soldered to 0.5 square inch copper area over backside ground plane or internal power plane, θJA can vary from 30 °C/W to more than 40 °C/W. Other mounting techniques can provide a thermal resistance lower than 30 °C/W. Pin Definitions Pin Number Pin Name Pin Function Descrition 1 VSense Remote Voltage Sense. Connect this pin to the load to permit true remote sensing and avoid trace drops. 2 ADJ/GND Adjust or Ground. On the FAN1581, this pin forms the feedback to determine the output voltage. On the FAN1581-1.2, -1.5 and -2.5, connect this pin to ground. 3 VOUT Output Voltage. This pin and the tab are output. 4 VCNTL Control Voltage. This pin draws small-signal power to control the FAN1581 circuitry. Connect to a voltage higher than VIN, as shown in the applications circuits. 5 VIN Input Voltage. Internal Block Diagram 4 VCNTL, Control 5 Vin, Power Thermal Shutdown Current Limit Vref 2 Voltage Loop Amplifier 3 Output 1 Sense 2 Adj REV. 1.2.0 11/6/03 PRODUCT SPECIFICATION FAN1581 Absolute Maximum Ratings Parameter VIN VCNTL Operating Junction Temperature Range Lead Temperature (Soldering, 10 sec.) Storage Temperature Range Min. Max. 7 13.2 125 300 150 0 -65 Unit V V °C °C °C Electrical Characteristics TJ=25°C, VOUT = VSENSE, VADJ = 0V unless otherwise specified. The • denotes specifications which apply over the specified operating temperature range. Parameter Reference Voltage3 Adjustable Output Voltage Output Voltage4 Output Voltage5 Output Voltage6 Line Regulation1,2 Load Regulation1,2 Dropout Voltage Minimum (VCNTL–VOUT) Dropout Voltage Minimum (VIN–VOUT) Dropout Voltage Minimum VIN Current Limit Control Pin Current Adjust Pin Current3 Minimum Load Current Ripple Rejection Thermal Resistance, Junction to Case Thermal Regulation Thermal Shutdown Conditions 2.05V ≤ VIN ≤ 5.5V, 2.7V ≤ VCNTL ≤ 12V, 10mA ≤ IOUT ≤ 5A 3V ≤ VIN ≤ 7V (function of Vout), 10mA ≤ IOUT ≤ 5A 3V ≤ VIN ≤ 7V, 10mA ≤ IOUT ≤ 5A 4V ≤ VIN ≤ 7V, 10mA ≤ IOUT ≤ 5A 2.7V ≤ VIN ≤ 7V, 10mA ≤ IOUT ≤ 5A 1.75V ≤ VIN ≤ 5.5V, 2.5V ≤ VCNTL ≤ 12V, IOUT = 10mA VIN = 2.1V, VCNTL = 2.75V, 10mA ≤ IOUT ≤ 5A VIN = 2.05V, ∆VREF = 1%, IOUT = 5A VCNTL = 2.75V, ∆VREF = 1%, IOUT = 5A VCNTL = 2.75V, ∆VREF = 1%, IOUT = 5A VIN = 2.05V, VCNTL = 2.75V VIN = 2.05V, VCNTL = 2.75V, IOUT = 10mA VIN = 2.05V, VCNTL = 2.75V VIN = 3.3V, VCNTL = 5V VIN = 3.75V, VCNTL = 3.75V, f = 120Hz, COUT = 22µF Tantalum, IOUT = 2.5A TO-263 SPAK TA = 25°C, 30ms pulse • Min. 1.237 Typ. 1.250 Max. 1.263 Units V • Vref 1.5 5.7 V • • • • 1.47 2.474 1.176 1.5 2.5 1.200 1 1.53 2.526 1.224 3 V V V mV • 1 5 mV • 1.05 1.18 V 0.4 0.5 V 0.5 0.6 V 3 6 A mA 50 5.0 80 120 10 • • • 5.2 • • 60 3 2 0.002 150 µA mA dB °C/W 0.02 %/W °C Notes: 1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant junction temperature by low duty cycle pulse testing. 2. Line and load regulation are guaranteed up to the maximum power dissipation (18W). Power dissipation is determined by input/output differential and the output current. Guaranteed maximum output power will not be available over the full input/ output voltage range. 3. FAN1581 only. 4. FAN1581-1.5 only. 5. FAN1581-2.5 only. 6. FAN1581-1.2 only. REV. 1.2.0 11/6/03 3 FAN1581 PRODUCT SPECIFICATION OUTPUT VOLTAGE DEVIATION (%) Typical Perfomance Characteristics 0.8 DROPOUT VOLTAGE (V) 0.7 0.6 T=125°C 0.5 0.4 0.3 T=25°C T=0°C 0.2 0.1 0.0 0 1 2 3 4 5 6 0.10 ∆Ι=5A 0.05 0 -0.05 -0.10 -0.15 -0.20 -50 -25 OUTPUT CURRENT (A) Dropout Voltage vs. Output Current 2.60 OUTPUT VOLTAGE (V) REFERENCE VOLTAGE 1.28 1.26 1.24 1.22 1.20 -75 -50 -25 2.5V 2.35 2.10 1.85 1.60 1.5V 1.35 1.2V 1.10 0 25 50 75 TJ (°C) 100 125 150 175 -75 -50 Reference Voltage vs. Temperature -25 0 25 50 TJ (°C) 75 100 125 150 175 Output Voltage vs. Temperature 70 10 ADJUST PIN CURRENT (µA) MINIMUM LOAD CURRENT (mA) 150 Load Regulation vs. Temperature 1.30 8 6 4 2 0 -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) Mimimum Load Current vs. Temperature 4 0 25 50 75 100 125 JUNCTION TEMPERATURE (°C) 60 50 40 30 20 10 0 -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) Adjust Pin Current vs. Temperature REV. 1.2.0 11/6/03 PRODUCT SPECIFICATION FAN1581 Typical Perfomance Characteristics (continued) 11 3.0 SHORT-CIRCUIT CURRENT (A) CONTROL PIN CURRENT (mA) 3.5 10mA Load 2.5 2.0 1.5 1.0 0.5 9 7 5 3 0 -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) Short-Circuit Current vs.Temeperature Control Pin Current vs. Temperature 90 20 70 15 60 POWER (W) RIPPLE REJECTIONS (dB) 80 50 40 10 30 (VIN—VOUT) ≤ 3V 20 5 0.5V ≤ VRIPPLE ≤ 2V 10 IOUT = 5A 0 0 10 100 1K 10K FREQUENCY (HZ) 100K 25 45 Ripple Rejection vs. Frequency 65 85 105 CASE TEMPERATURE 125 Maximum Power Dissipation MAX. ACCEPTABLE ESR, OHM 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 1 2 3 LOAD CURRENT, A 4 5 FAN1581 Stability REV. 1.2.0 11/6/03 5 FAN1581 General The FAN1581, FAN1581-1.2, FAN1581-1.5, and FAN1581-2.5 are three-terminal regulators optimized for DDR and GTL+ VTT termination and logic applications. These devices are short-circuit protected, and offer thermal shutdown to turn off the regulator when the junction temperature exceeds about 150°C. The FAN1581 series provides low dropout voltage and fast transient response. Frequency compensation uses capacitors with low ESR while still maintaining stability. This is critical in addressing the needs of low voltage high speed microprocessor buses like GTL+. VIN and VCNTL Functions The FAN1581 utilizes a dual supply approach to maximize efficiency. The collector of the power device is brought out to the VIN pin to minimize internal power dissipation under high current loads. VCNTL provides power for the control circuitry and the drive for the output NPN transistor. VCNTL should be at least 1.2 V higher than the output voltage. Special care was taken to ensure there are no supplysequencing problems. The output voltage will not turn on until both supplies are operating. If the control voltage comes up first, the output current will be typically limited to about 3.0 mA until the power input voltage comes up. If the power input voltage comes up first the output will not turn on at all until the control voltage comes up. The output can never come up unregulated. The FAN1581 can also be used as a single supply device with the control and power inputs tied together. In this mode, the dropout is determined by the minimum control voltage. PRODUCT SPECIFICATION A protection diode between the input and output pins is usually not needed. An internal diode between the input and the output pins on the FAN1581 series can handle microsecond surge currents of 50A to 100A. Even with large value output capacitors it is difficult to obtain those values of surge currents in normal operation. Only with large values of output capacitance, such as 1000µF to 5000µF, and with the input pin instantaneously shorted to ground can damage occur. A crowbar circuit at the input can generate those levels of current; a diode from output to input is then recommended, as shown in Figure 1. Usually, normal power supply cycling or system “hot plugging and unplugging” will not generate current large enough to do any damage. D1 1N4002 (OPTIONAL) VOUT VIN The FAN1581 series requires an output capacitor as a part of the frequency compensation. It is recommended to use a 22µF solid tantalum or a 100µF aluminum electrolytic on the output to ensure stability. The frequency compensation of these devices optimizes the frequency response with low ESR capacitors. In general, it is suggested to use capacitors with an ESR of < 0.3Ω. It is also recommended to use bypass capacitors such as a 22µF tantalum or a 100µF aluminum on the adjust pin of the FAN1581 for low ripple and fast transient response. When these bypassing capacitors are not used at the adjust pin, smaller values of output capacitors provide equally good results. A graph showing stability of output capacitance ESR vs load current can be found under Typical Performance Characteristics. Protection Diodes In normal operation, the FAN1581 series does not require any protection diodes. For the FAN1581, internal resistors limit internal current paths on the adjust pin. Therefore, even with bypass capacitors on the adjust pin, no protection diode is needed to ensure device safety under short-circuit conditions. 6 Vsense FAN1581 C1 10µF Vin + Adj Vout + R1 VOUT C2 22µF R2 CADJ D1 1N4002 (OPTIONAL) VCNTL VIN Stability Vcntl + Vcntl + Vsense FAN1581 C1 10µF Vin Gnd Vout + VOUT C2 22µF Figure 1. Optional Protection Diode Ripple Rejection In applications that require improved ripple rejection, a bypass capacitor from the adjust pin of the FAN1581 to ground reduces the output ripple by the ratio of VOUT/1.25V. The impedance of the adjust pin capacitor at the ripple frequency should be less than the value of R1 (typically in the range of 100Ω to 120Ω) in the feedback divider network in Figure 1. Therefore, the value of the required adjust pin capacitor is a function of the input ripple frequency. For example, if R1 equals 100Ω and the ripple frequency equals 120Hz, the adjust pin capacitor should be 22µF. At 10kHz, only 0.22µF is needed. Output Voltage The FAN1581 regulator develops a 1.25V reference voltage between the output pin and the adjust pin (see Figure 2). Placing a resistor R1 between these two terminals causes a constant current to flow through R1 and down through R2 to set the overall output voltage. Normally, this current is the specified minimum load current of 10mA. REV. 1.2.0 11/6/03 PRODUCT SPECIFICATION FAN1581 The current out of the adjust pin adds to the current from R1 and is typically 50µA. Its output voltage contribution is small and only needs consideration when a very precise output voltage setting is required. Vcntl Vcntl For example, look at using an FAN1581M-1.5 to generate 5A @ 1.5V ± 2% from a 3.3V source (3.2V to 3.6V). Vsense FAN1581 Vin Adj Vout VIN + VOUT VREF C1 10µF IADJ 50µA + R1 C2 22µF R2 VOUT = VREF (1+R2/R1) + IADJ (R2) Figure 2. Basic Regulator Circuit Load Regulation The FAN1581 family provides true remote sensing, eliminating output voltage errors due to trace resistance. To utilize remote sensing, connect the VSENSE pin directly to the load, rather than at the VOUT pin. If the load is more than 1" away from the FAN1581, it may be necessary to increase the load capacitance to ensure stability. Thermal Considerations The FAN1581 series protect themselves under overload conditions with internal power and thermal limiting circuitry. However, for normal continuous load conditions, do not exceed maximum junction temperature ratings. It is important to consider all sources of thermal resistance from junction-toambient. These sources include the junction-to-case resistance, the case-to-heat sink interface resistance, and the heat sink resistance. Thermal resistance specifications have been developed to more accurately reflect device temperature and ensure safe operating temperatures. The electrical characteristics section provides a separate thermal resistance and REV. 1.2.0 11/6/03 maximum junction temperature for both the control circuitry and the power transistor. Calculate the maximum junction temperature for both sections to ensure that both thermal limits are met. Assumptions: • • • • • Vin = 3.6V worst case VOUT = 1.47V worst case IOUT = 5A continuous TA = 40°C Θ Case-to-Ambient = 5°C/W (assuming both a heatsink and a thermally conductive material) The power dissipation in this application is: PD = (VIN - VOUT) * (IOUT) = (3.6-1.47) * (5) = 10.65W From the specification table, TJ = TA + (PD) * (Θ Case-to-Ambient + ΘJC) = 40 + (10.65) * (5 + 3) = 125°C The junction temperature is within the maximum rating. Junction-to-case thermal resistance is specified from the IC junction to the bottom of the case directly below the die. This is the lowest resistance path for heat flow. Proper mounting ensures the best thermal flow from this area of the package to the heat sink. Use of a thermally conductive material at the case-to-heat sink interface is recommended. Use a thermally conductive spacer if the case of the device must be electrically isolated and include its contribution to the total thermal resistance. 7 FAN1581 PRODUCT SPECIFICATION U1 VIN = 3.3V 10µF VIN + C1 VSENSE FAN1581 VOUT 2.1V at 5A VCNTL VCNTL = 5V 1µF C4 Adj 10µF C3 + R1 124Ω R2 86.6Ω 100µF C2 Figure 3. Application Circuit (FAN1581) Table 1. Bill of Materials for Application Circuit for the FAN1581 Item Quantity Manufacturer Part Number Description C1, C3 2 Xicon L10V10 10µF, 10V Aluminum C2 1 Xicon L10V100 100µF, 10V Aluminum C4 1 Any 1µF Ceramic R1 1 Generic 124Ω, 1% R2 1 Generic U1 1 Fairchild 86.6Ω, 1% FAN1581P 5A Regulator U1 VIN = 2.5V 10µF C1 VIN + FAN1581–1.5 VOUT VCNTL VCNTL = 3.3V 1µF VSENSE 1.5V at 5A + GND C2 100µF C3 Figure 4. Application Circuit (FAN1581-1.5) Table 2. Bill of Materials for Application Circuit for the FAN1581-1.5 Item 8 Quantity Manufacturer Part Number Description C1 1 Xicon L10V10 10µF, 10V Aluminum C2 1 Any C3 1 Xicon L10V100 100µF, 10V Aluminum U1 1 Fairchild FAN1581P-1.5 5A Regulator 1µF Ceramic REV. 1.2.0 11/6/03 PRODUCT SPECIFICATION FAN1581 U1 VIN = 3.3V + 10µF C1 VIN VSENSE FAN1581–2.5 VOUT VCNTL VCNTL = 5V + 2.5V at 5A + GND 1µF C2 100µF C3 Figure 5. Application Circuit (FAN1581-2.5) Table 3. Bill of Materials for Application Circuit for the FAN1581-2.5 Item Quantity Manufacturer Part Number Description C1 1 Xicon L10V10 10µF, 10V Aluminum C2 1 Any C3 1 Xicon L10V100 100µF, 10V Aluminum U1 1 Fairchild FAN1581P-2.5 5A Regulator REV. 1.2.0 11/6/03 1µF Ceramic 9 PRODUCT SPECIFICATION FAN1581 Mechanical Dimensions 5-Lead TO-263 Package A 10.20 9.80 1.40 1.00 9.50 MIN 9.40 9.00 9.00 MIN 10.00 5.10 4.70 1 5 4.00 MIN 1.37 1.17 0.90 0.70 (1.28) 1.70 1.70 0.25 6.80 M B AM 1.20 MIN 6.80 LAND PATTERN RECOMMENDATION –B– 4.70 4.30 (8.00) (4.40) 1.40 1.14 R0.45 (1.75) (0.90) (6.80) SEE DETAIL A 15.60 15.00 5 1 NOTES: UNLESS OTHERWISE SPECIFIED A) ALL DIMENSIONS ARE IN MILLIMETERS. B) STANDARD LEAD FINISH: 200 MICROINCHES/ 5.08 MICROMETERS MIN. LEAD/TIN 15/85 ON COPPER. C) NO PACKAGE STANDARD REFERENCE AS OF JUNE 2002. D) DIMENSIONING AND TOLERANCING PER ANSI Y14.5M – 1982. GAGE PLANE R0.56 0.75 0.45 SEATING PLANE 2.84 2.24 0.25 0.10 B 8° 0° DETAIL A, ROTATED 90° SCALE: 10X REV. 1.2.0 11/6/03 10 FAN1581 PRODUCT SPECIFICATION Mechanical Dimensions (continued) 5-Lead TO-252 Package 6.00 MIN A 6.80 6.35 5.64 5.04 1.27 0.50 6.56 MIN 6.30 5.90 6.25 1.02 0.60 3.00 MIN C 1 3 2 1 5 4 1.27 (0.44) 0.57±0.07 1.27 1.00 3.81 0.69±0.15 1.27 0.25 M A M C LAND PATTERN RECOMMENDATION 5.08 B 2.40 2.18 0.60 0.40 (5.09) (4.05) 10.42 9.20 SEE DETAIL A 3 5 4 2 1 0.10 B GAGE PLANE 0.60 0.40 0.51 (1.54) NOTES: UNLESS OTHERWISE SPECIFIED 10° 0° 1.78 1.40 A) ALL DIMENSIONS ARE IN MILLIMETERS. B) THIS PACKAGE CONFORMS TO JEDEC, TO-252, ISSUE C, VARIATION AA, DATED NOV. 1999. 0.13 MAX (2.90) SEATING PLANE DETAIL A (ROTATED 90°) SCALE: 2X 11 REV. 1.2.0 11/6/03 FAN1581 PRODUCT SPECIFICATION Mechanical Dimensions (continued) TO-220 Package B 3.96 Ø 3.53 4.82 4.19 1.39 0.88 10.54 9.90 A 7° 15.87 14.47 13.69 11.81 9.39 8.38 5° 5° 26.54 24.00 1.01 0.50 (1.30) 0.635 0.304 0.36 M B A L 1.70 2.92 2.15 6.80 3° 3° NOTES: UNLESS OTHERWISE SPECIFIED A) B) C) D) 12 STANDARD LEAD FINISH: 200 MICROINCHES / 5.08 MICROMETERS MIN. LEAD/TIN 15/85 ON COPPER. REFERENCE JEDEC, TS–001, ISSUE A, VARIATION AA, DATED AUGUST 1989 ALL DIMENSIONS ARE IN MILLIMETERS. DIMENSIONING AND TOLERANCING PER ASME Y14.5M–1994. REV. 1.2.0 11/6/03 FAN1581 PRODUCT SPECIFICATION Ordering Information Product Number Package FAN1581MX TO-263 in Tape and Reel FAN1581DX TO-252 DPAK in Tape and Reel FAN1581M12X TO-263 in Tape and Reel FAN1581D15X TO-252 DPAK in Tape and Reel FAN1581M25X TO-263 in Tape and Reel FAN1581D25X TO-252 DPAK in Tape and Reel FAN1581T TO-220 in Tape and Reel DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 11/6/03 0.0m 002 Stock#DS30001581 2003 Fairchild Semiconductor Corporation