www.fairchildsemi.com FAN1084 4.5A Adjustable/Fixed Low Dropout Linear Regulator Features Description • • • • • The FAN1084, FAN1084-1.5, and FAN1084-3.3 are low dropout three-terminal regulators with 4.5A 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 FAN1084 is ideal for low voltage microprocessor applications requiring a regulated output from 1.5V to 3.6A with an input supply of 5V or less. The FAN1084-1.5 offers fixed 1.5V with 4.5A current capabilities for GTL+ bus VTT termination. The FAN1084-3.3 offers a fixed 3.3V output at 4.5A. Fast transient response Low dropout voltage at up to 4.5A Load regulation: 0.5% typical On-chip thermal limiting Standard TO-220, TO-263 center cut, and TO-252 packages Applications • • • • • • • Desktop PCs, RISC and embedded processors’ supply GTL, SSTL logic Reference bus supply Low voltage VCC logic supply Battery-powered circuitry Post regulator for switching supply Cable and ADSL modems’ DSP core supply Set Top Boxes and Web Boxes modules’ supply On-chip thermal limiting provides protection against any combination of overload and ambient temperature that would create excessive junction temperatures. The FAN1084 series regulators are available in the industrystandard TO-220, TO-263 center cut, and TO-252 (DPAK) power packages. Application Diagrams FAN1084 VOUT VIN VIN = 5V + ADJ 10µF 2.5V at 4.5A + 124Ω 22µF 124Ω FAN1084-1.5 VIN VOUT VIN = 3.3V + 10µF GND 1.5V at 4.5A + 22µF REV. 1.0.8 11/10/03 FAN1084 PRODUCT SPECIFICATION Pin Assignments FAN1084M-3.3† FAN1084M-1.5 FRONT VIEW FAN1084M FAN1084D-3.3 FAN1084D-1.5 FRONT VIEW FAN1084T FAN1084T-3.3 FAN1084T-1.5 FRONT VIEW FRONT VIEW FAN1084D FRONT VIEW FRONT VIEW Tab is out. 1 2 1 3 2 3 Tab is out. 1 2 3 1 IN ADJ 2 1 2 3 3 GND GND IN 1 2 3 ADJ IN 3-Lead Plastic TO-263 ΘJC=3°C/W* GND OUT IN ADJ OUT IN IN 3-Lead Plastic TO-220 ΘJC=3°C/W* 3-Lead Plastic TO-252 ΘJC=3°C/W* *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 may provide better power dissipation than 30°C/W. † FAN1084M-3.3 also available with uncut center lead. Absolute Maximum Ratings Parameter Min. Max. Unit 7 V 0 125 °C –65 150 °C 300 °C VIN Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 seconds) 2 REV. 1.0.8 11/10/03 PRODUCT SPECIFICATION FAN1084 Electrical Characteristics Operating Conditions: 4.75 ≤ VIN < 5.25V, Tj = 25°C unless otherwise specified. Parameter Conditions Min. Typ. Max Units Reference Voltage Adj connected to ground, IOUT = 10mA 1.23 1.250 1.27 V Output Voltage5 IOUT = 10mA 1.475 1.5 1.525 V 6 Output Voltage IOUT = 10mA 3.234 3.3 3.366 V Line Regulation1, 2 IOUT = 10mA 0.5 2 % 10mA ≤ IOUT ≤ 4.5A 0.5 2.5 % 1.5 V 3 Load Regulation1, 2 Dropout Voltage ∆VREF% = 2%, IOUT = 4.5A Current Limit (VIN – VOUT) = 2V 5.5 Adjust Pin Current3 35 A 100 µΑ 1.5V ≤ (VIN – VOUT) ≤ 5.75V 10 mA Quiescent Current4 VIN = 5V 4 mA Thermal Resistance, Junction to Case TO-220 3 °C/W TO-263 Center Cut, TO-252 3 °C/W 150 °C Mimimum Load Thermal Current4 Shutdown4 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. Power dissipation is determined by input/ output differential and the output currrent. Guaranteed maximum output power will not be available over the full input/output voltage range. 3. FAN1084 only. 4. Guaranteed by design. 5. FAN1084-1.5 only. 6. FAN1084-3.3 only. Typical Performance Characteristics POWER (W) 20 15 10 5 0 25 45 65 85 105 125 CASE TEMPERATURE Figure 1. Maximum Power Dissipation REV. 1.0.8 11/10/03 3 FAN1084 PRODUCT SPECIFICATION Typical Performance Characteristics (Continued) 1.5 ∆I = 4.5A DROPOUT VOLTAGE (V) 1.4 1.3 1.2 1.1 1.0 T=0°C 0.9 T=125°C T=25°C 0.8 0.7 0.6 0.5 0 1 2 3 4 5 6 OUTPUT CURRENT (A) Figure 2. Dropout Voltage vs. Output Current 1.275 1 1.270 REFERENCE VOLTAGE (V) Figure 3. Load Regulation vs. Temperature OUT 1 VOUT = 3.6V 1.265 1.260 1.255 1.250 1.245 1.240 1.235 VOUT = 3.3V 1 1.230 1.225 -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) Figure 4. Reference Voltage vs. Temperature Figure 5. Output Voltage vs. Temperature MINIMUM LOAD CURRENT (mA) 5 4 3 2 1 0 -75 -50 -25 0 25 50 75 100 125 150 175 JUNCTION TEMPERATURE (°C) Figure 6. Minimum Load Current vs. Temperature 4 Figure 7. Adjust Pin Current vs. Temperature REV. 1.0.8 11/10/03 PRODUCT SPECIFICATION FAN1084 Typical Performance Characteristics (continued) 90 8.0 RIPPLE REJECTIONS (dB) SHORT-CIRCUIT CURRENT (A) 80 7.0 6.0 5.0 70 60 50 40 30 (VIN – VOUT) ≤ 3V 0.5V ≤ VRIPPLE ≤ 2V IOUT = 5A 20 10 4.0 -75 -50 -25 0 0 10 25 50 75 100 125 150 175 100 1K 10K 100K FREQUENCY (Hz) JUNCTION TEMPERATURE (°C) Figure 8. Short-Circuit Current vs. Temperature Figure 9. Ripple Rejection vs. Frequency OUTPUT CAPACITANCE ESR, (Ω) 2.5 2 1.5 Area of Instability 1 0.5 Stable Area 0 0 1000 2000 3000 4000 LOAD CURRENT (mA) Figure 10. Stability Region VIN/VOUT = 5V/1.5V REV. 1.0.8 11/10/03 5 FAN1084 Applications Information General The FAN1084, FAN1084-1.5, and FAN1084-3.3 are threeterminal regulators optimized for 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 FAN1084 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+. PRODUCT SPECIFICATION The adjust pin can be driven on a transient basis ±7V with respect to the ouput, without any device degradation. As with any IC regulator, exceeding the maximum input-to-output voltage differential causes the internal transistors to break down and none of the protection circuitry is then functional. D1 1N4002 (OPTIONAL) FAN1084 VIN + IN C1 10µF OUT + ADJ R1 VOUT C2 22µF Stability The FAN1084 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 <0.2Ω. It is also recommended to use bypass capacitors such as a 22µF tantalum or a 100µF aluminum on the adjust pin of the FAN1084 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. Refer to Typical Performance Characteristics for graph of stability of output capacitance ESR vs load current. Protection Diodes In normal operation, the FAN1084 series does not require any protection diodes. For the FAN1084, 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. 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 FAN1084 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 2. Usually, normal power supply cycling or system “hot plugging and unplugging” will not generate current large enough to do any damage. 6 + CADJ R2 D1 1N4002 (OPTIONAL) FAN1084-1.5 VIN + IN C1 10µF OUT GND + VOUT C2 22µF Figure 2. Optional Protection Ripple Rejection In applications that require improved ripple rejection, a bypass capacitor from the adjust pin of the FAN1084 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 2. 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 FAN1084 regulator develops a 1.25V reference voltage between the ouput pin and the adjust pin (see Figure 3). 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. 1.0.8 11/10/03 PRODUCT SPECIFICATION FAN1084 The current out of the adjust pin adds to the current from R1. Its output voltage contribution is small and only needs consideration when a very precise output voltage setting is required. RP Parasitic Line Resistance FAN1084 FAN1084 VIN + IN VIN OUT C1 10µF ADJ + VREF IADJ 35µA R1 IN VOUT C2 22µF OUT ADJ R1* R2 *Connect R1 to case Connect R2 to load RL R2* Figure 3. Connection for Best Load Regulation Figure 5. Connection for Best Load Regulation Load Regulation It is not possible to provide true remote load sensing because the FAN1084 series are three-terminal devices. Load regulation is limited by the resistance of the wire connecting the regulator to the load. Load regulation per the data sheet specification is measured at the bottom of the package. For fixed voltage devices, negative side sensing is a true Kelvin connection with the ground pin of the device returned to the negative side of the load. This is illustrated in Figure 4. RP Parasitic Line Resistance FAN1084-1.5 VIN IN OUT GND RL Thermal Conditions The FAN1084 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-to-ambient. These sources include the junction-to-case resistance, the case-to-heatsink 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 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. For example, look at using a FAN1084T to generate 4.5A @ 1.5V from a 3.3V source (3.2V to 3.6V). Figure 4. Connection for Best Load Regulation For adjustable voltage devices, negative side sensing is a true Kelvin connection with the bottom of the output divider returned to the negative side of the load. The best load regulation is obtained when the top of the resistor divider R1 connects directly to the regulator output and not to the load. Figure 5 illustrates this point. If R1 connects to the load, then the effective resistance between the regulator and the load would be: RP X (1 + R2/R1), RP = Parasitic line Resistance The connection shown in Figure 5 does not multiply RP by the divider ration. As an example, RP is about four milliohms per foot with 16-gauge wire. This translates to 4mV per foot at 1A load current. At higher load currents, this drop represents a significant percentage of the overall regulation. It is important to keep the positive lead between the regulator and the load as short as possible and to use large wire or PC board traces. REV. 1.0.8 11/10/03 Assumptions • • • • • VIN = 3.4V worst case VOUT = 1.475V worst case IOUT = 4.5A continuous TA = 60°C θCase-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 – 1.475) * (4.5) = 9.6W From the specification table: TJ = TA + (PD) * (θCase-to-Ambient + θJC) = 60 + (9.6) * (5 + 3) = 137°C The junction temperature is below the maximum thermal limit. 7 FAN1084 PRODUCT SPECIFICATION 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. The cases of the FAN1084 series are directly connected to the output of the device. U1 FAN1084 VIN + IN C1 10µF OUT R1 124Ω ADJ + C2 100µF + VOUT C3 2.5V 100µF R2 124Ω Figure 6. Application Circuit Table 1. Bill of Materials for Application Circuit for the FAN1084 Item Quantity Manufacturer Part Number Description C1 1 Xicon L10V10 10µF, 10V Aluminum C2, C3 2 Xicon L10V100 100µF, 10V Aluminum FAN1084T 4.5A Regulator R1, R2 2 Generic U1 1 Fairchild 124Ω, 1% U1 RC1084-1.5 VIN = 3.3V IN C1 10µF + VOUT 1.5V OUT + GND C3 100µF Figure 7. Application Circuit (FAN1084-1.5) Table 2. Bill of Materials for Application Circuit for the FAN1084-1.5 8 Item Quantity Manufacturer Part Number Description C1 1 Xicon L10V10 10µF, 10V Aluminum C3 1 Xicon L10V100 100µF, 10V Aluminum U1 1 Fairchild FAN1084T-1.5 4.5A Regulator REV. 1.0.8 11/10/03 PRODUCT SPECIFICATION FAN1084 Mechanical Dimensions 3-Lead TO-263 Center Cut Package Inches Symbol Millimeters Notes Min. Max. Min. Max. A b b2 c2 D E e .160 .020 .190 .036 4.06 0.51 4.83 0.91 L L1 L2 .575 .090 — .050 .017 0° .049 .051 .045 .055 .340 .380 .380 .405 .100 BSC L3 R α .625 .110 .055 .070 .019 8° 1.25 1.30 1.14 1.40 8.64 9.65 9.65 10.29 2.54 BSC 14.61 2.29 — 1.27 0.43 0° Notes: 1. Dimensions are exclusive of mold flash and metal burrs. 2. Standoff-height is measured from lead tip with ref. to Datum -B-. 3. Foot length is measured with ref. to Datum -A- with lead surface (at inner R). 4. Dimensiuon exclusive of dambar protrusion or intrusion. 5. Formed leads to be planar with respect to one another at seating place -C-. 15.88 2.79 1.40 1.78 0.78 8° E @PKG/ @HEATSINK L2 c2 D E-PIN L R (2 PLCS) b2 L1 L3 b e -B- -A- A -C- REV. 1.0.8 11/10/03 9 FAN1084 PRODUCT SPECIFICATION Mechanical Dimensions 3-Lead TO-263 Package Symbol Inches Millimeters Notes Min. Max. Min. Max. A b b2 c2 D E e .160 .020 .190 .036 4.06 0.51 4.83 0.91 L L1 L2 R α .575 .090 — .017 0° .049 .051 .045 .055 .340 .380 .380 .405 .100 BSC .625 .110 .055 .019 8° 1.25 1.30 1.14 1.40 8.64 9.65 9.65 10.29 2.54 BSC 14.61 2.29 — 0.43 0° Notes: 1. Dimensions are exclusive of mold flash and metal burrs. 2. Standoff-height is measured from lead tip with ref. to Datum -B-. 3. Foot length is measured with ref. to Datum -A- with lead surface (at inner R). 4. Dimensiuon exclusive of dambar protrusion or intrusion. 5. Formed leads to be planar with respect to one another at seating place -C-. 15.88 2.79 1.40 0.78 8° E @PKG/ @HEATSINK L2 c2 D E-PIN L R (2 PLCS) b2 L1 b e -B- -A- A -C- 10 REV. 1.0.8 11/10/03 PRODUCT SPECIFICATION FAN1084 Mechanical Dimensions (continued) 3-Lead TO-220 Package Inches Symbol Min. A b b1 c1 øP D E e Millimeters Max. Min. .140 .190 .015 .040 .045 .070 .014 .022 .139 .161 .560 .650 .380 .420 .090 .110 .190 .210 .045 — .020 .055 .230 .270 .080 .115 .500 .580 .250 BSC .100 .135 3° 7° e1 e3 F H1 J1 L L1 Q α Notes Max. 3.56 4.83 .38 1.02 1.14 1.78 .36 .56 3.53 4.09 14.22 16.51 9.65 10.67 2.29 2.79 4.83 5.33 1.14 — .51 1.40 5.94 6.87 2.04 2.92 12.70 14.73 6.35 BSC 2.54 3.43 3° 7° Notes: 1. Dimension c1 apply for lead finish. H1 Q L e3 b1 e e1 E b L1 E-PIN øP α (5X) c1 A J1 D REV. 1.0.8 11/10/03 F 11 FAN1084 PRODUCT SPECIFICATION Mechanical Dimensions (continued) 3-Lead TO-252 Package A 6.73 6.35 5.46 5.21 6.00 MIN L3 4 6.50 MIN D 6.25 1.02 0.84 C 1 3.00 MIN 2 3 1 1.14 0.78 (0.59) 0.89 0.54 2.30 1.40 MIN 4.80 2.29 4.57 0.25 M A M C 3 LAND PATTERN RECOMMENDATION B 2.38 2.18 SEE NOTE D E1 0.58 0.48 4 D1 10.41 9.40 SEE DETAIL A 2 3 1 0.10 B 0.61 0.48 (1.54) 10° 0° 1.78 1.40 0.127 MAX 2.90 SEATING PLANE DETAIL A (ROTATED –90° SCALE 12X 12 NOTES: UNLESS OTHERWISE SPECIFIED A) ALL DIMENSIONS ARE IN MILLIMETERS. B) THIS PACKAGE CONFORMS TO JEDEC, TO-252, ISSUE C. VARIATION AA & AB, DATED NOV. 1999. 0.51 GAGE PLANE C) DIMENSIONING AND TOLERANCING PER ASME Y14.5–1994. D) HEAT SINK TOP EDGE COULD BE IN CHAMFERED CORNERS OR EDGE PROTRUSION. E) DIMENSIONS L3, D, E1 & D1 TABLE: OPTION AA OPTION AB L3 0.89 – 1.27 1.52 – 2.03 D 5.97 – 6.22 5.33 – 5.59 E1 4.32 MIN 3.81 MIN D1 5.21 MIN 4.57 MIN REV. 1.0.8 11/10/03 FAN1084 PRODUCT SPECIFICATION Ordering Information Product Number Package FAN1084MC TO-263 Center Cut FAN1084T TO-220 FAN1084D TO-252 FAN1084MC15 TO-263 Center Cut FAN1084T15 TO-220 FAN1084D15 TO-252 FAN1084MC33 TO-263 Center Cut FAN1084M33 TO-263 FAN1084T33 TO-220 FAN1084D33 TO-252 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 11/10/03 0.0m 003 Stock#DS30001084 2001 Fairchild Semiconductor Corporation