FAN1587A

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FAN1587A

3A Adjustable/Fixed Low Dropout Linear Regulator

Features

••••••

Fast transient response

Low dropout voltage at up to 3ALoad regulation: 0.05% typicalTrimmed current limitOn-chip thermal limiting

Standard TO-220, TO-263, TO-263 center cut, and TO-252 packages

Description

The FAN1587A, FAN1587A-1.5, and FAN1587A-3.3 are low dropout three-terminal regulators with 3A output current capa-bility. These devices have been optimized for low voltage applications including VTT bus termination, where transient response and minimum input voltage are critical. The

FAN1587A is ideal for low voltage microprocessor applica-tions requiring a regulated output from 1.5V to 3.6V with an input supply of 12V or less. The FAN1587A-1.5 offers fixed 1.5V with 3A current capability for GTL+ bus VTT termina-tion. The FAN1587A-3.3 offers fixed 3.3V current capability for logic IC operation.

Current limit is trimmed to ensure specified output current and controlled short-circuit current. On-chip thermal limiting pro-vides protection against any combination of overload and ambient temperature that would create excessive junction temperatures.

The FAN1587A, FAN1587A-1.5, and FAN1587A-3.3 are available in the industry-standard TO-220, TO-263, TO-263 center cut, and TO-252 (DPAK) power packages.

Applications

•••••

Pentium® Class GTL+ bus supplyLow voltage logic supply

Post regulator for switching supply12V to 5V linear regulator3.3V to 1.5V linear regulator

Typical ApplicationsVIN = 12V22µF+FAN1587AVINVOUTADJR1124ΩR2768Ω+9V at 3A22µFVOUT = VREF (1+R2/R1)+IADJ*R2FAN1587A-3.3VIN = 9V22µF+VINVOUTGND3.3V at 3A+22µF65-1587-16Pentium is a registered trademark of Intel Corporation.

REV. 1.0.3 3/14/02

PRODUCT SPECIFICATION

FAN1587A

Pin Assignments

FAN1587ATFRONT VIEWFAN1587AT-1.5, -3.3VFRONT VIEWFAN1587AM-1.5FRONT VIEWFAN1587AMFRONT VIEWTab is Out.Tab is Out.123123123123GNDOUTINADJOUTINADJOUTINGNDOUTIN3-Lead Plastic TO-263θJC = 3°C/W*3-Lead Plastic TO-220θJC = 3°C/WFAN1587AMC-1.5, 3.3FRONT VIEWFAN1587AMCFRONT VIEWFAN1587AD-1.5, 3.3FRONT VIEWFAN1587ADFRONT VIEWTab is Out.Tab is Out.123123GNDGNDINADJININADJIN1231233-Lead Plastic TO-263 Center CutθJC = 3°C/W*3-Lead Plastic TO-252θJC = 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 can provide a thermal resistance lower than 30°C/W. 2REV. 1.0.3 3/14/02

PRODUCT SPECIFICATIONFAN1587A

Absolute Maximum RatingsParameterVIN(VIN – VOUT) * IOUTOperating Junction Temperature RangeStorage Temperature RangeLead Temperature (Soldering, 10 sec.)0-65Min.Max.18See Figure 1125150300°C°C°CUnitV4IOUT (Amps)321002468101214VIN–VOUT (V)Figure 1. Absolute Maximum Safe Operating AreaREV. 1.0.3 3/14/023

FAN1587A

PRODUCT SPECIFICATION

Electrical Characteristics

Tj = 25°C unless otherwise specified.

The • denotes specifications which apply over the specified operating temperature range.ParameterReference Voltage3Output Voltage4, 6Output Voltage5, 6Line Regulation1, 2Load Regulation1, 2Dropout VoltageCurrent LimitAdjust Pin Current3Adjust Pin Current Change3, 6

Minimum Load CurrentQuiescent CurrentRipple RejectionThermal RegulationTemperature StabilityLong-Term StabilityRMS Output Noise (% of VOUT)Thermal Resistance, Junction to CaseThermal Shutdown

TA = 125°C, 1000 hrs.TA = 25°C, 10Hz ≤ f ≤ 10kHzTO-220TO-263, TO-252

1.5V ≤ (VIN – VOUT) ≤ 12V, 10mA ≤ IOUT ≤ 3A1.5V ≤ (VIN – VOUT) ≤ 12VVIN = 5V

f = 120Hz, COUT = 22µF Tantalum, (VIN – VOUT) = 3V, IOUT = 3ATA = 25°C, 30ms pulse

•

Conditions

1.5V ≤ (VIN – VOUT) ≤ 8.25V, 10mA ≤ IOUT ≤ 3A3.0V ≤ VIN ≤ 8.5V10mA ≤ IOUT ≤ 3A4.8V ≤ VIN ≤ 10.3V10mA ≤ IOUT ≤ 3A

(VOUT + 1.5V) ≤ VIN ≤ 12V, IOUT = 10mA(VIN – VOUT) = 3V10mA ≤ IOUT ≤ 3A∆VREF = 1%, IOUT = 3A(VIN – VOUT) = 2V

•••••••••••

6010

4720.0040.50.030.00333150

1.00.0213

3.1Min.1.225(-2%)1.473.234

Typ.1.2501.53.30.0050.051.1504350.2

1205Max1.275(+2%)1.533.3660.20.51.300

UnitsVVV%%VAµAµAmAmAdB%/W%%%°C/W°C/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 currrent. Guaranteed maximum output power will not be available over the full input/output voltage range.3.FAN1587A only.4.FAN1587A-1.5 only.5.FAN1587A-3.3 only.

6.Output current must be limited to meet the absolute maximum ratings of the part.

REV. 1.0.3 3/14/024

FAN1587APRODUCT SPECIFICATION

Typical Performance Characteristics

1.5OUTPUT VOLTAGE DEVIATION (%)0.100.050-0.05-0.1065-1587-04∆I = 3A1.4DROPOUT VOLTAGE (V)1.31.21.11.00.90.80.70.60.500.511.522.5T=25°CT=0°CT=125°C65-1587-03-0.15-0.20-75-50-253.00255075100125150175OUTPUT CURRENT (A)JUNCTION TEMPERATURE (°C)Figure 2. Dropout Voltage vs. Output CurrentFigure 3. Load Regulation vs. Temperature

1.2601.255REFERENCE VOLTAGE (V)REFERENCE VOLTAGE (V)3.703.653.603.553.503.453.403.353.303.25VOUT SET WITH 1% RESISTORSVOUT = 3.6V11.2501.2451.2401.2351.2301.22565-1587-05VOUT = 3.3V21.2151.210-75-50-2502550751001251501753.20-75-50-25Note:1. FAN1587A Only2. FAN1587A, -3.30255075100125150175JUNCTION TEMPERATURE (°C)JUNCTION TEMPERATURE (°C)Figure 4. Reference Voltage vs. TemperatureFigure 5. Output Voltage vs. Temperature

5MINIMUM LOAD CURRENT (mA)10090Note:1. FAN1587A Only4ADJUST PIN CURRENT (µA)80706050403065-1587-083265-1587-07120100-75-50-2500-75-50-250255075100125150175255075100125150175JUNCTION TEMPERATURE (°C)JUNCTION TEMPERATURE (°C)Figure 6. Minimum Load Current vs. TemperatureFigure 7. Adjust Pin Current vs. Temperature

5REV. 1.0.3 3/14/02

65-1587-061.220PRODUCT SPECIFICATIONFAN1587A

Typical Performance Characteristics (continued)5.0SHORT-CIRCUIT CURRENT (A)9080RIPPLE REJECTIONS (dB)4.57060504030201001065-1587-104.03.565-1587-09(VIN – VOUT) ≤ 3V0.5V ≤ VRIPPLE ≤ 2VIOUT = 3A1001KFREQUENCY (Hz)10K3.0-75-50-250255075100125150175100KJUNCTION TEMPERATURE (°C)Figure 8. Short-Circuit Current vs. TemperatureFigure 9. Ripple Rejection vs. Frequency20151065-1587-11POWER (W)505060708090100110120130140150CASE TEMPERATURE (°C)Figure 10. Maximum Power DissipationREV. 1.0.3 3/14/026

PRODUCT SPECIFICATIONFAN1587A

Applications InformationGeneralThe FAN1587A, FAN1587A-1.5, and FAN1587A-3.3 are three-terminal regulators optimized for GTL+ VTT termina-tion 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 FAN1587A 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 microproces-sor buses like GTL+.D11N4002(OPTIONAL)FAN1587AVINC122µF+INADJ+CADJOUTR1+VOUTC222µFR2StabilityThe FAN1587A series require 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. It is recommended to use bypass capacitors such as a 22µF tantalum or a 100µF aluminum on the adjust pin of the FAN1587A for low ripple and fast transient response. When these bypassing capacitors are not used at the adjust pin, larger values of output capacitors provide equally good results.D11N4002(OPTIONAL)FAN1587A-1.5, -3.3VINC122µF+INGNDOUT+VOUTC222µF65-1587-13Figure 11. Optional ProtectionProtection DiodesIn normal operation, the FAN1587A series does not require any protection diodes. For the FAN1587A, 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 shortcircuit condi-tions.A protection diode between the input and output pins is usu-ally not needed. An internal diode between the input and out-put pins on the FAN1587A 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 cur-rents 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 cur-rent; a diode from output to input is then recommended, as shown in Figure 11. Usually, normal power supply cycling or system “hot plugging and unplugging” will not generate current large enough to do any damage.The adjust pin can be driven on a transient basis ±7V with respect to the output, 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.Ripple RejectionIn applications that require improved ripple rejection, a bypass capacitor from the adjust pin of the FAN1587A to ground reduces the output ripple by the ratio of VOUT/1.25V. The impedance of the adjust pin capacitor at the ripple fre-quency should be less than the value of R1 (typically in the range of 100Ω to 120Ω) in the feedback divider network in Figure 11. 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 VoltageThe FAN1587A regulator develops a 1.25V reference volt-age between the output pin and the adjust pin (see Figure 12). 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. The current out of the adjust pin adds to the current from R1 and is typically 35µA. Its output voltage contribution is small and only needs consideration when very precise output voltage setting is required.REV. 1.0.3 3/14/027

FAN1587APRODUCT SPECIFICATION

FAN1587AVIN+INC122µFADJIADJ35µAVOUT = VREF (1 + R2/R1) + IADJ (R2)OUTVREFR1+VOUTC222µFVININFAN1587AOUTADJRP PARASITICLINE RESISTANCER265-1587-14R1*RLFigure 12. Basic Regulator Circuit*CONNECT R1 TO CASECONNECT R2 TO LOADR2*Load RegulationIt is not possible to provide true remote load sensing because the FAN1587A series are three-terminal devices. Load regu-lation is limited by the resistance of the wire connecting the regulators 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 13.FAN1587A-1.5, -3.3OUTINGNDRP PARASITICLINE RESISTANCERL65-1587-15Figure 14. Connection for Best Load RegulationThermal ConsiderationsThe FAN1587A 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 impor-tant to consider all sources of thermal resistance from junc-tion-to-ambient. 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 tempera-ture and ensure safe operating temperatures. For example, look at using an FAN1587AT to generate 3A @ 1.5V ± 2% from a 3.3V source (3.2V to 3.6V).Assumptions:VIN65-1587-17Figure 13. Connection for Best Load RegulationFor 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 regu-lation is obtained when the top of resistor divider R1 con-nects directly to the regulator output and not to the load. Figure 14 illustrates this point. If R1 connects to the load, then the effective resistance between the regulator and the load would be:RP × (1 + R2/R1), RP = Parasitic Line ResistanceThe connection shown in Figure 14 does not multiply RP by the divider ratio. 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 repre-sents 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.•••••VIN = 3.6V worst caseVOUT = 1.46V worst caseIOUT = 3A continuousTA = 70°CθCase-to-Ambient = 3°C/W (assuming both a heatsink and a thermally conductive material)The power dissipation in this application is:PD = (VIN – VOUT) * (IOUT) = (3.6 – 1.46) * (3) = 6.42WFrom the specification table:TJ = TA + (PD) * (θCase-to-Ambient + θJC) = 70 + (6.42) * (3 + 3) = 109°CThe junction temperature is below the maximum rating.8REV. 1.0.3 3/14/02

FAN1587APRODUCT 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 electri-cally isolated and include its contribution to the total thermal resistance. The cases of the FAN1587A series are directly connected to the output of the device.

VIN12VC122µFU1FAN1587AVIN+ADJC2100µF+VOUTR1124ΩR2768Ω+VOUT9VC3100µF65-1587-18Figure 15. Application Circuit (FAN1587A)

Table 1. Bill of Materials for Application Circuit for the FAN1587A

ItemC1C2, C3R1R2U1

Quantity

12111

Manufacturer

XiconXiconGenericGenericFairchild

FAN1587ATPart NumberL16V22L10V100

Description22µF, 16V Aluminum100µF, 10V Aluminum124Ω, 1%768Ω, 1%3A Regulator

9REV. 1.0.3 3/14/02

FAN1587APRODUCT SPECIFICATION

Mechanical Dimensions3-Lead TO-263 PackageSymbolAbb2c2DEeLL1L2RαInchesMin..160.020Max..190.036MillimetersMin.4.060.51Max.4.830.91NotesNotes: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-..049.051.045.055.340.380.380.405.100 BSC.575.090—.0170°.625.110.055.0198°1.251.301.141.408.9.659.6510.292.54 BSC14.612.29—0.430°15.882.791.400.788°E@PKG/@HEATSINKL2c2DLb2 eE-PINR (2 PLCS)L1b-B--A-A-C-10REV. 1.0.3 3/14/02

PRODUCT SPECIFICATIONFAN1587A

Mechanical Dimensions (continued)3-Lead TO-263 Center Cut PackageSymbolAbb2c2DEeLL1L2L3RαInchesMin..160.020Max..190.036MillimetersMin.4.060.51Max.4.830.91NotesNotes: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-..049.051.045.055.340.380.380.405.100 BSC.575.090—.050.0170°.625.110.055.070.0198°1.251.301.141.408.9.659.6510.292.54 BSC14.612.29—1.270.430°15.882.791.401.780.788°E@PKG/@HEATSINKL2c2DLb2E-PINR (2 PLCS)L1 eL3b-B--A-A-C-REV. 1.0.3 3/14/0211

PRODUCT SPECIFICATIONFAN1587A

Mechanical Dimensions (continued)3-Lead TO-220 PackageInchesMin.Max..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.100.1353°7°MillimetersMin.Max.3.5.83.381.021.141.78.36.563.534.0914.2216.519.6510.672.292.794.835.331.14—.511.405.946.872.042.9212.7014.736.35 BSC2.543.433°7°SymbolAbb1c1øPDEee1e3FH1J1LL1QαNotesNotes:1. Dimension c1 apply for lead finish.H1Le3e1eb1QEbL1E-PINøPα(5X)c1J1DAFREV. 1.0.3 3/14/0212

FAN1587APRODUCT SPECIFICATION

Mechanical Dimensions (continued)

3-Lead TO-252 Package

SymbolAbb2b3cc2DEeHLL1L3L4InchesMin..086.025.030.205.018.018Max..094.035.045.215.024.023MillimetersMin.2.190.0.765.210.460.46Max.2.390.1.145.460.610.584Notes:Notes1. Dimensions are exclusive of mold flash, metal burrs or interlead protrusion.2.3.4.5.116.Stand off-height is measured from lead tip with ref. to Datum -B-. Foot length is measured with ref. to Datum -A- with lead surface.Thermal pad contour optional within dimension b3 and L3.Formed leads to be planar with respect to one another at seating place -C-.Dimensions and tolerances per ASME Y14.5M-1994..210.245.250.265.090 BSC.370.410.055.070.108 REF.035.025.080.0405.336.226.356.732.29 BSC9.4010.411.401.782.74 REF0.0.2.031.0234E@PKG/@HEATSINKb3L3c2DHb2 eα = 0° – 10°-A-E-PINL4L1Lb-B-A-C-13REV. 1.0.3 3/14/02

FAN1587APRODUCT SPECIFICATION

Ordering InformationProduct NumberFAN1587AMXFAN1587AMCXFAN1587ATFAN1587ADXFAN1587AM15XFAN1587AMC15XFAN1587AT15FAN1587AD15XFAN1587AM33XFAN1587AMC33XFAN1587AT33FAN1587AD33XPackageTO-263 in tape-and-reelTO-263 center cut in tape-and-reelTO-220TO-252 in tape-and-reelTO-263 in tape-and-reelTO-263 center cut in tape-and-reelTO-220TO-252 in tape-and-reelTO-263 in tape-and-reelTO-263 center cut in tape-and-reelTO-220TO-252 in tape-and-reelDISCLAIMER

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.

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