SPX1085 3A Low Dropout Voltage Regulator Adjustable & Fixed Output, Fast Response FEATURES APPLICATIONS • Adjustable Output Down To 1.2V • Fixed Output Voltages 1.5, 2.5, 3.3, 5.0V • Output Current Of 3A • Low Dropout Voltage 1.1V Typ. • Extremely Tight Load And Line Regulation • Current & Thermal Limiting • Standard 3-Terminal Low Cost TO-220, TO-263 & TO-252 • Similar To Industry Standard LT1085/LT1585 • Powering VGA & Sound Card • Power PC Supplies • SMPS Post-Regulator • High Efficiency “Green” Computer Systems • High Efficiency Linear Power Supplies • Portable Instrumentation • Constant Current Regulators • Adjustable Power Supplies • Battery charger PRODUCT DESCRIPTION The SPX1085 are low power 3A adjustable and fixed voltage regulators that are very easy to use. It requires only 2 external resistors to set the output voltage for adjustable version. The SPX1085 is designed for low voltage applications that offer lower dropout voltage and faster transient response. This device is an excellent choice for use in powering low voltage microprocessor that require a lower dropout, faster transient response to regulate from +2.5V to 3.8V supplies and as a post regulator for switching supplies applications. The SPX1085 features low dropout of a maximum of 1.5 volts. The SPX1085 offers full protection against over-current faults, reversed input polarity, reversed load insertion, and positive and negative transient voltage. On-Chip trimming adjusts the reference voltage to 1%. The IQ of this device flows into load which increases efficiency. The SPX1085 are offered in a 3-pin TO-220, TO-263 & TO-252 packages compatible with other 3 terminal regulators. For a 8A low dropout regulator refer to the SPX1085 data sheet. PIN CONNECTIONS TO-263-3 (T) TO-220-3 (U) SPX1085 1 2 TO-252 (R) SPX1085 3 SPX1085 1 2 1 2 3 3 ADJ/GND VOUT VIN Front View ADJ/GND VOUT VIN Top View ADJ/GND VOUT VIN Front View Rev. 10/30/00 SPX1085 ABSOLUTE MAXIMUM RATINGS Lead Temp. (Soldering, 10 Seconds) .............................. 300°C Storage Temperature Range ............................ -65° to +150°C Operating Junction Temperature Range ...................... SPX1085 Control Section.......................... -45°C +125°C SPX1085 Power Transistor.........................-45°C +150°C Input Voltage........................................................ 30V Input to Output Voltage Differential Max ............ 30V ELECTRICAL CHARACTERISTICS (NOTE 1) at IOUT = 10mA, TA=25°C, unless otherwise specified. SPX1085A PARAMETER CONDITIONS Typ Min Max SPX1085 Min Max Units 1.5V Version Output Voltage (Note 2) SPX1085-1.5V, 0 ≤IOUT≤3A, 2.75V≤VIN ≤29V 1.5 1.5 1.485 1.470 1.515 1.530 1.470 1.455 1.530 1.545 V 2.5V Version Output Voltage (Note 2) SPX1085-2.5V,0 ≤IOUT≤3A, 3.5V≤VIN ≤29V 2.5 2.5 2.475 2.450 2.525 2.550 2.450 2.425 2.550 2.575 V 3.3V Version Output Voltage (Note 2) SPX1085-3.3V, 0 ≤IOUT≤3A, 4.75V≤VIN ≤29V 3.3 3.3 3.270 3.240 3.330 3.360 3.230 3.201 3.370 3.399 V 5.0V Version Output Voltage (Note 2) SPX1085-5.0V, 0 ≤IOUT≤3A, 5.5V≤VIN ≤29V 5.0 5.0 4.95 4.90 5.05 5.10 4.900 4.850 5.100 5.150 V 1.250 1.238 1.263 1.225 1.270 V Adjustable Version Reference Voltage (VREF) All Voltage Options Min. Load Current (Note 3) Line Regulation (∆VREF(VIN)) VIN≤ 7V, P≤ PMAX 1.5V≤ (VIN -VOUT)≤(VIN-VOUT)MAX, 10mA≤IOUT≤3A 5 10 10 mA 2.75V≤VIN ≤29V, IOUT=10mA, TJ=25°C (Note 3) 0.005 0.2 0.2 % VIN ≤29V, IOUT=0mA, TJ=25°C (Note 2) 0.005 0.2 0.2 % 10mA≤IOUT ≤3A, (VIN-VOUT)=3V, TJ=25°C (Note 3) 0.05 0.3 0.3 % 0≤IOUT ≤3A, VIN=7V, TJ=25°C (Note 2) 0.05 0.3 0.3 % Dropout Voltage ∆VREF=1% 1.1 1.5 1.5 V Current Limit IOUT(MAX) Long Term Stability VIN=7V 1.4V≤ (VIN- VOUT) (Note3) TA=125°C, 1000 Hrs. 0.3 (Note 2) 1 1 % Thermal Regulation (∆VOUT(Pwr)) Temperature Stability (∆VOUT(T)) Output Noise, RMS Thermal Resistance TA=25°C, 20 ms pulse 0.01 0.020 0.020 %/W Load Regulation(∆VREF(IOUT)) 1.5V≤ (VIN -VOUT)≤ (VIN-VOUT)MAX IOUT =3A (Note 3) IOUT≤ 3A (Note 2) A 4.0 3.2 3.2 0.25 10Hz to 10kHz TO-220 DD Package TA=25°C Junction to Tab Junction to Ambient Junction to Tab Junction to Ambient % 0.003 3.0 60 3.0 60 % VO 3.0 60 3.0 60 3.0 60 3.0 60 °C/W °C/W The Bold specifications apply to the full operating temperature range. Note 1: Changes in output voltage due to heating effects are covered under the specification for thermal regulation. Note 2: Fixed Version Only Note 3: Adjustable Version Only Rev. 10/30/00 SPX1085 APPLICATION HINTS The SPX1085 incorporates protection against over-current faults, reversed load insertion, over temperature operation, and positive and negative transient voltage. However, the use of an output capacitor is required in order to insure the stability and the performances. Reducing parasitic resistance and inductance One solution to minimize parasitic resistance and inductance is to connect in parallel capacitors. This arrangement will improve the transient response of the power supply if your system requires rapidly changing current load condition. Stability The output capacitor is part of the regulator’s frequency compensation system. Either a 220µF aluminum electrolytic capacitor or a 47µF solid tantalum capacitor between the output terminal and ground guarantees stable operation for all operating conditions. However, in order to minimize overshoot and undershoot, and therefore optimize the design, please refer to the section ‘Ripple Rejection’. Thermal Consideration Although the SPX1085 offers some limiting circuitry for overload conditions, it is necessary not to exceed the maximum junction temperature, and therefore to be careful about thermal resistance. The heat flow will follow the lowest resistance path, which is the Junction-to-case thermal resistance. In order to insure the best thermal flow of the component, a proper mounting is required. Note that the case of the device is electrically connected to the output. In case the case has to be electrically isolated, a thermally conductive spacer can be used. However do not forget to consider its contribution to thermal resistance. Ripple Rejection Ripple rejection can be improved by adding a capacitor between the ADJ pin and ground. When ADJ pin bypassing is used, the value of the output capacitor required increases to its maximum (220µF for an aluminum electrolytic capacitor, or 47µF for a solid tantalum capacitor). If the ADJ pin is not bypass, the value of the output capacitor can be lowered to 100µF for an electrolytic aluminum capacitor or 15µF for a solid tantalum capacitor. However the value of the ADJ-bypass capacitor should be chosen with respect to the following equation: C = 1 / ( 6.28 * FR * R1 ) Where C = value of the capacitor in Farads (select an equal or larger standard value), FR = ripple frequency in Hz, R1 = value of resistor R1 in Ohms. If an ADJ-bypass capacitor is use, the amplitude of the output ripple will be independent of the output voltage. If an ADJbypass capacitor is not used, the output ripple will be proportional to the ratio of the output voltage to the reference voltage: M = VOUT / VREF Where M = multiplier for the ripple seen when the ADJ pin is optimally bypassed. VREF = Reference Voltage Assuming: VIN = 10V, VOUT = 5V, IOUT = 1.5A, TA = 50°C θ Heatsink = 6°C/W, θ Case-Heatsink = 0.5°C/W, θ JC = 3°C/W Power dissipation under this condition PD = (VIN – VOUT) * IOUT = 7.5W Junction Temperature TJ = TA + PD * (θCase – HS + θ HS + θ JC) For the Control Sections TJ = 50 + 7.5*(0.5 +6=3) = 121.25°C 121.25°C < TJ(max) for the control section. In both case reliable operation is insured by adequate junction temperature. Rev. 10/30/00 SPX1085 Basic Adjustable Regulator VIN VOUT SPX1085 VREF R1 IADJ 50µA R2 VOUT = VREF * ( 1 + R2/R1) + IADJ * R2 Fig.2 Basic Adjustable Regulator Output Voltage Consider Figure 2. The resistance R1 generates a constant current flow, normally the specified load current of 10mA. This current will go through the resistance R2 to set the overall output voltage. The current IADJ is very small and constant. Therefore its contribution to the overall output voltage is very small and can generally be ignored Load Regulation Parasitic line resistance can degrade load regulation. In order not to affect the behavior of the regulator, it is best to connect directly the R1 resistance from the resistor divider to the case, and not to the load. For the same reason, it is best to connect the resistor R2 to the Negative side of the load. VIN R P Parasitic Line Resistance SPX1085 Connect R 1 to Case of Regulator R1 RL R2 Connect R 2 to Load Fig.3 Basic Adjustable Regulator Rev. 10/30/00 SPX1085 TYPICAL APPLICATIONS VIN IN SPX1085 VIN OUT C2 Fig. 5 Typical Adjustable Regulator Fig. 4 3A Current output Regulator IN SPX1085 + 10µF 5V *C 1 improves ripple rejection. Xc should be ~ R 1 at ripple frequency. VOUT OUT ADJ R2 VOUT = VREF (1 + R2 ) + IADJ R2 R1 LOAD (Note A) R1 ADJ R1 ADJ VOUT OUT C1 C1 VIN SPX1085 IN VIN IN C1 10µF* 121Ω 1% ADJ + 150µF + 5V (Note A) R1 121Ω 1% R2 365Ω 1% SPX1085 OUT TTL Input + 10µF 100µF 1k 2N3904 365Ω 1% 1k Note A: VIN(MIN) = (Intended VOUT) + (VDROPOUT (MAX)) Note A: VIN(MIN)= (Intended VOUT) + (VDROPOUT (MAX)) Fig. 6 Improving Ripple Rejection Fig.7 5V Regulator with Shutdown Rev. 10/30/00 SPX1085 TYPICAL CHARACTERISTICS Rev. 10/30/00 SPX1085 ORDERING INFORMATION Ordering No. Precision Output Voltage SPX1085T SPX1085T-1.5 SPX1085T-2.5 SPX1085T-3.3 SPX1085T-5.0 SPX1085AT SPX1085AT-1.5 SPX1085AT-2.5 SPX1085AT-3.3 SPX1085AT-5.0 SPX1085U SPX1085U-1.5 SPX1085U-2.5 SPX1085U-3.3 SPX1085U-5.0 SPX1085AU SPX1085AU-1.5 SPX1085AU-2.5 SPX1085AU-3.3 SPX1085AU-5.0 SPX1085R SPX1085R-1.5 SPX1085R-2.5 SPX1085R-3.3 SPX1085R-5.0 SPX1085AR SPX1085AR-1.5 SPX1085AR-2.5 SPX1085AR-3.3 SPX1085AR-5.0 2% 2% 2% 2% 2% 1% 1% 1% 1% 1% 2% 2% 2% 2% 2% 1% 1% 1% 1% 1% 2% 2% 2% 2% 2% 1% 1% 1% 1% 1% Adj 1.5V 2.5V 3.0V 5.0V Adj 1.5V 2.5V 3.0V 5.0V Adj 1.5V 2.5V 3.0V 5.0V Adj 1.5V 2.5V 3.0V 5.0V Adj 1.5V 2.5V 3.0V 5.0V Adj 1.5V 2.5V 3.0V 5.0V Packages 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-263 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-220 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 3 Lead TO-252 Corporation SIGNAL PROCESSING EXCELLENCE Sipex Corporation Headquarters and Main Offices: 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: [email protected] 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 935-7600 FAX: (408) 934-7500 Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described hereing; neither does it convey any license und under it patent rights nor the rights of others. Rev. 10/30/00