350mA Low Drop Out Voltage Regulator with Shutdown

SPX2955/56/57 350mA Low Drop Out Voltage Regulator with Shutdown (PRELIMINARY INFORMATION) FEATURES • Output Accuracy 5V, 3.3V@ 350mA Output • Very Low Quiescent Current • Low Dropout Voltage • Extremely Tight Load And Line Regulation • Very Low Temperature Coefficient • Current & Thermal Limiting • Error Flag Warns Of Output Dropout • Logic-Controlled Electronic Shutdown • Output Programmable From 1.24V to 29V APPLICATIONS • Battery Powered Systems • Cordless Telephones • Radio Control Systems • Portable/Palm Top/Notebook Computers • Portable Consumer Equipment • Portable Instrumentation • Automotive Electronics • SMPS Post-Regulator • Voltage Reference PRODUCT DESCRIPTION The SPX2955/56/57 is a low power voltage regulator. This device is an excellent choice for use in battery-powered applications such as cordless telephones, radio control systems, and portable computers. The SPX2955/56/57 features very low quiescent current (100µA Typ.) and very low dropout voltage. This includes a tight initial tolerance of 1% max and 2% max., and very low output temperature coefficient, making the SPX2955/56/57 useful as a low-power voltage reference. The error flag output feature is used as power-on reset for warning of a low output voltage, due to a falling voltage input of batteries. Another feature is the logic-compatible shutdown input which enables the regulator to be switched on and off. The SPX2955/56/57 is offered in 3-pin and 5-pin TO-220 package compatible with other 5 volt and adjustable regulators, in 8-Pin Plastic Dip SO-8 (same pin out as SPX2951) and surface mount TO-263 packages. The regulator output voltage (of the 8-pin package and 5-pin TO-220 & TO-263) may be pin-strapped for a 5V and 3.3V or programmed from 1.24V to 29V with an external pair of resistors. Look for SPX2951 for 150mA and SPX2954 for 250mA applications. PIN CONNECTIONS TO-220-3 Package TO-263-5 Package TO-220-5 Package 8-Pin Surface Mount OUTPUT 1 2 SPX2955 3 2 1 VOUT GND VIN 8 INPUT FEEDBACK 5V/ 3.3V TAP ERROR SPX2956/57 SENSE Five Lead Package Pin Functions: SPX2956 SPX2957 1) ERROR 2) INPUT 3) GND 4) OUTPUT 5) SHUTDOWN ADJUST SHUTDOWN GND INPUT OUTPUT SPX2956/57 SHUTDOWN GROUND ALPHA 7 AS2930 3 SPX29556 4 5 Front View TO-263-3 Package Top View 1 2 345 3 VOUT 12345 SPX2955 Top View 2 GND 1 V IN Top View Front View Rev. 11/21/00 SPX2955/56/57 ABSOLUTE MAXIMUM RATINGS Power Dissipation..........................................Internally Limited Lead Temp. (Soldering, 5 Seconds) ................................ 260°C Storage Temperature Range .............................. -65° to +150°C Operating Junction Temperature Range (Note 9) SPX2955/56/57...................................... -40C° to +125°C Operating Input Supply Voltage....................... 3.0V to +60V Feedback Input Voltage ..................................-1.5V to +30V Shutdown Input Voltage..................................-0.3V to +30V Error Comparator Output ................................-0.3V to +30V ESD Rating ............................................................ 2KV Min ELECTRICAL CHARACTERISTICS at VS=±15V,TA=25°C, unless otherwise specified. Boldface applies over the full operating temperature range. PARAMETER 3.3V Version Output Voltage -40°C ≤TJ ≤+125°C CONDITIONS (Note 2) Typ. SPX2955/56/57A Min Max 3.267 3.217 3.333 3.382 SPX2955/56 Min Max 3.234 3.185 3.366 3.415 UNITS 3.3 3.3 V 1mA ≤IL ≤ 350mA 5V Version Output Voltage -40°C ≤TJ ≤+125°C 1mA ≤IL ≤ 350mA 5.0 5.0 4.950 4.880 5.050 5.120 4.900 4.870 5.100 5.130 V All Voltage Options Output Voltage Temperature Coefficient Line Regulation ( Note 3) Load Regulation ( Note 3 ) Dropout Voltage ( Note 5 ) 20 (Note 1) 6V ≤ VIN ≤30V (Note 4) IL = 1 to 350mA IL = 0.1 to 1mA IL = 1mA IL = 100mA IL = 250mA IL = 350mA Ground Current IL = 1mA IL = 100mA IL = 250mA IL = 350mA Current Limit Thermal Regulation Output Noise, 10Hz to 100kHz IL = 100mA VOUT = 0 0.05 400 260 0.03 0.04 60 220 250 375 50 0.5 4 5 SPX2955/56/57A 100 0.1 0.40 0.20 0.30 100 150 250 300 300 420 400 500 100 150 1 2 8 10 10 15 700 800 0.2 SPX2955/56/57 150 0.20 0.80 0.30 0.50 100 150 250 300 350 420 500 600 100 150 1 2 8 10 10 15 700 800 0.2 ppm/°C %max %max mV µA mA mA %/w µV Vrms CL = 2.2µF CL = 33µF Rev. 11/21/00 SPX2955/56/57 (Continued) PARAMETER Adjustable Versions only Reference Voltage Reference Voltage Feedback Pin Bias Current Reference Voltage Temperature Coefficient Feedback Pin Bias Current Temperature Coefficient Over Temperature (Note 6) 20 (Note 7) 50 nA/°C 0.1 V0H = 30V VIN = 4.5V I0L = 400µA (Note 8) (Note 8) (Note 8) Low (Regulator ON) High (Regulator OFF) VS = 2.4V VS = 30V Regulator Output Current in Shutdown 0.01 150 60 75 15 40 25 95 140 1.00 2.00 250 400 40 25 95 140 1.00 2.00 250 400 µA mV mV mV mV V 1.3 30 450 3 10 20 2.0 0.7 50 100 600 750 2.0 0.7 90 150 800 1000 15 25 µA CONDITIONS (Note 2) Typ. Typ. 1.235 SPX2955/57A Min Max SPX2955/57A 1.210 1.260 1.200 1.270 1.185 1.285 40 60 SPX2955/57 Min Max SPX2955/57B 1.200 1.270 1.990 1.280 1.185 1.285 60 80 UNITS V V NA ppm/°C Error Comparator Output Leakage Current Output Low Voltage Upper Threshold Voltage Lower Threshold Voltage Hysteresis Shutdown Input Input logic Voltage Shut down Pin Input Current µA Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range. Note 2: Unless otherwise specified all limits are guaranteed for Tj = 25°C, VIN = 6V, IL = 100µA and CL = 1µF. Additional conditions for the 8-pin versions are feedback tied to 5V tap and output tied to output sense (VOUT = 5V) and VSHUTDOWN ≤ 0.8V. Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered under the specification for thermal regulation. Note 4: Line regulation for the SPX2955/56/57 is tested at 150°C for IL = 1 mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%. See typical performance characteristics for line regulation versus temperature and load current. Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential at very low values of programmed output voltage, the minimum input supply voltage of 2V ( 2.3V over temperature) must be taken into account. Note 6: VREF ≤VOUT ≤ (Vin - 1V), 2.3 ≤Vin≤30V, 100µA≤IL≤ 250 mA, TJ ≤ TJMAX. Note 7: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at 6V input. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed. Note 8: VSHUTDOWN ≥ 2V, VIN ≤ 30V, VOUT =0, Feedback pin tied to 5V Tap. Note 9: The junction -to-ambient thermal resistance of the TO-92 package is 180°C/ W with 0.4” leads and 160°C/ W with 0.25” leads to a PC board. The thermal resistance of the 8-Pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient thermal resistance for the SOIC (S) package is 160°C/W. Rev. 11/21/00 SPX2955/56/57 UNREGULATED DC 7 FEEDBACK 8 INPUT 1 OUTPUT 2 SENSE + _ FROM CMOS OR TTL 3 SHUTDOWN 60k Ω .. 180k Ω .. ERROR AMPLIFIER 6 5V TAP 5 ______ ERROR TO CMOS OR TTL 4 REFERENCE GROUND + 1µF .. 330k Ω .. 5V @ 350mA MAX + + 60 mV + 1.23V + _ ERROR DETECTION COMPARATOR SPX2955/56/57 Block Diagram Rev. 11/21/00 SPX2955/56/57 APPLICATION HINTS EXTERNAL CAPACITORS The stability of the SPX2955/56/57 requires a 2.2µF or greater capacitor between output and ground. Oscillation could occur without this capacitor. Most types of tantalum or aluminum electrolytic works fine here. For operations of below -25°C solid tantalum is recommended since the many aluminum types have electrolytes the freeze at about –30°C. The ESR of about 5Ω or less and resonant frequency above 500kHz are the most important parameters in the value of the capacitor. The capacitor value can be increased without limit. At lower values of output current, less output capacitance is required for stability. For the currents below 10mA the value of the capacitor can be reduced to 0.5µF and 0.15µF for 1mA. More output capacitance needed for the 8-pin version at voltages below 5V since it runs the error amplifier at lower gain. At worst case 5µF or greater must be used for the condition of 250mA load at 1.23V output. The SPX2955/56/57, unlike other low dropout regulators will remain stable and in regulation with no load in addition to the internal voltage divider. This feature is especially important in application like CMOS RAM keep-alive. When setting the output voltage of the SPX2955/56/57, a minimum load of 10mA is recommended. If there is more than 10 inches of wire between the input and the AC filter capacitor or if a battery is used as the input then a 0.1µF tantalum or aluminum electrolytic capacitor should be placed from the input to the ground. Instability can occur if there is stray capacitance to the SPX2955/56/57 feedback terminal (pin 7). This could cause more problems when using a higher value of external resistors to set the output voltage. This problem can be fixed by adding a 100pF capacitor between output and feedback and increasing the output capacitor to at least 3.3µF. ERROR DETECTION COMPARATOR OUTPUT The Comparator produces a logic low output whenever the SPX2955/56/57 output fal