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| * DATA SHEET LND2950 / LND2951 100mA Low Dropout Voltage Regulators GENERAL DESCRIPTION The LND2950-XX is a low power voltage regulator.This device is an excellent choice for use in battery powered application such as cordless telephone, radio control systems, and portable computers. The LND2950-XX/LND2951-XX features very low quiescent current (75A Typ.) and very low drop output voltage (Typ. 40mV at light load and 380mV at 100mA).This includes a tight initial tolerance of 0.5% typ., extremely good load and line regulation of 0.05% typ., and very low output temperature coefficient, making the LND2950-XX/LND2951-XX useful as a low-power voltage reference. The error flag output feature is used as power-on reset, warning of a low output voltage, due to falling battery voltage on input. Another feature is the logiccompatible shutdown input, which enables the regulator to be switched on and off. 8 dip The LND2951-XX is available in 8 pin plastic packages. The regulator output voltage may be pinstrapped for a -XX voltage or programmed from 1.24 volts to 29 volts with an external pair of resistors. The LND2950-XX is offered in a 3-pin TO-92 package compatible with other fixed regulators. FEATURES * * * * * * * * * * High accuracy output voltage Guaranteed 100mA output Very low quiescent current Low dropout voltage Extremely tight load and line regulation Very low temperature coefficient Needs only 1F for stability Error Flag warns of output dropout Logic-Controlled electronic shutdown Output programmable from 1.24 to 29V APPLICATIONS * * * * * * * * * Battery powered systems Cordless telephones Radio control systems Portable/Palm Top/ notebook computers Portable Instrumentation Avionics Automotive Electronics SMPS Post-Regulator Voltage Reference DEVICE SELECTION GUIDE VOUT, Volts 2.85* 3.0 3.3 5.0 Device LND2950-2.85,LND2951-2.85 LND2950-3.0,LND2951-3.0 LND2950-3.3, LND2951-3.3 LND2950-5.0, LND2951-5.0 *Other versions are also available Vout=2.0V TO 5.0V. Please consult for more information * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND2950 / LND2951 ABSOLUTE MAXIMUM RATING Power Dissipation Lead Temperature (Soldering, 5 seconds) Storage Temperature Range Operating Junction Temperature Range Input Supply Voltage Feedback Input Voltage Shutdown Input Voltage Error Comparator Output Internally Limited 260 -65C to+150C -55C to +150 -0.3 to+30V -1.5 to+30V -0.3 to +30V -0.3 to +30V PIN CONFIGURATION Output Sense Shutdown GND 1 2 3 4 8 7 6 5 Input Feedback -XX V tap Error OUTPUT GND INPUT LND2951-XX 8-Pin Plastic (Top View) +V IN TO-92 (Bottom View) 100k ERROR OUTPUT 5 ERROR 8 VIN V OUT 1 V OUT 1.2 0.01F R1 GND 4 FB 7 1.23V 30V + 3.3 F LND2951 SHUTDOWN 3 INPUT Off On Note : pins 2 and 6 are left open V OUT =V (1+ R1/R2) REF V REF R2 Figure 1: Adjustable Regulator * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND2950 / LND2951 ELECTRICAL CHARACTERISTICS PARAMETER Output Voltage Output Voltage Output Voltage Temperature Coefficient Line Regulation(Note 3) Load Regulation( Note3) Dropout Voltage(Note 5) Ground Current Dropout Ground Current Current Limit Thermal regulation Output Noise,10Hz to 100KHz 8-PIN Versions Only Reference Voltage Reference Voltage Feedback Pin Bias Current Reference Voltage Temperature Coefficient Feedback Pin Bias Current Temperature Coefficient 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 (TA=25 C, VIN=15V Unless otherwise noted) CONDITIONS (note 2) -25C Tj 85C Full Operating Temperature 100A IL 100mA, TJ TJMAX (note 1) VO+1VVIN 30V(Note 4) 100A IL 100mA IL= 100A IL= 100mA IL= 100A IL= 100mA VIN =V0 =-0.5V,IL =100A Vout=0 CL= 1F CL=200F CL= 3.3F (Bypass=0.01F pins 7 to 1 (LND2951-XX)) MIN 0.985 |Vo| 0.98 |Vo| 0.976 |Vo| TYP VO VO 50 0.04 0.1 50 380 75 8 110 160 0.05 430 160 100 MAX 1.015 |Vo| 1.02 |Vo| 1.024 |Vo| 150 0.4 0.3 80 450 120 12 170 200 0.2 UNITS V ppm/C % % mV A mA A mA %/W V rms Over temperature(Note 6) (note 7) 1.21 1.185 1.235 20 50 0.1 1.26 1.285 40 V nA ppm/C nA/C Voh=30V Vin=4.5V,IOL=400A (note 8) (note 8) (note 8) Low(Regulator ON) High (Regulator OFF) Vs= 2.4V Vs=30V (Note 9) Vout=5.0V 3.3VVout<5.0V 2.0VVout<3.3V 40 0.01 150 60 75 15 1.3 1.0 250 95 A mV 0.7 50 600 10 20 30 2 30 450 3 V Regulator Output current in Shutdown A * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND2950 / LND2951 Note 1: Output or reference voltage temperature coefficients is defined as the worst case voltage change divided by the total temperature range. Note 2: Unless otherwise specified all limits guaranteed for Tj =25C, Vin=Vo +1V,IL=100Aand CL =1F. Additional conditions for the 8 pin versions are feedback tied to -XX V tap and output tied to output sense(Vout =XX V) and V shutdown 0.8 V. Note 3: Regulations 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 LND2951-xx is tested at 150Cfor IL=1mA. For IL =100A and Tj=125C, line regulation is guaranteed by design to 0.2%. See typical performance characteristics for line regulation verse temperature and load current. Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV 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), 2.3V Vin 30V,100AIL 100mA,TJ TJMAX Note 7: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 8: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at VO +1V 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 95mVx5V/1.235V=384mV. 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 9: Vshutdown 2V,Vin 30V,Vout =0, Feed-back pin tied to -XX V tap. APPLICATION HINTS External Capacitors A 1.0 F (or greater ) capacitor is required between the output and the ground for stability at output voltages of 5V or more. At lower output voltages, more capacitance is required. 2.2 F or more is recommended for 3 V and 3.3 V versions. Programming the Output Voltage The LND2951 may be pin-strapped for the nominal fixed output voltage. Alternatively it may be programmed for any output voltage between 1.24 V and 29 V depending upon the requirements. BLOCK DIAGRAM AND TYPICAL APPLICATIONS Unregulated DC + Unregulated DC 7 FEEDBACK INPUT 8 1 OUTPUT 2 OUTPUT Vout I <= 100mA L + ERROR AMPLIFIER + See Application Hints From CMOS or TTL 3 SHUTDOWN + + 60 mV + 1.23 V Reference + Vout I <= 100mA L INPUT SENSE + See Application Hints + - 6 ERROR AMPLIFIER XX VTAP 330k 5 II 60k ERROR + 1.23 V Reference To CMOS or TTL 4 GROUND Error detection Comparator GROUND * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * LND2950 / LND2951 TYPICAL APPLICATIONS +V IN 8 ERROR OUTPUT 5 ERROR +V IN V OUT 1 *V OUT V IN 5V BUS +V IN OUT LND29500Z-5.0 V *V OUT 5V + 1 F LND2951 SHUTDOWN 3 INPUT GND 4 FB 7 GND *Minimum input-output voltage ranges from 40mV to 400mV, depending on load current. Current limit is typically 160mA. *Minimum input-output voltage ranges from 40mV to 400mV, depending on load current. Current limit is typically 160mA. Wide Input Voltage Range Current Limiter 5V Current Limiter +V=1.2 I L +V IN 8 470k V 8 5 470k ERROR +V IN V OUT 1 V OUT F + 1 R1 FB 7 GND 4 SHUTDOWN 3 SD INPUT GND 4 FB 7 R 1% IN LOAD 30V I = 1.23/R L 1 V OUT *V OUT LND2951 1 F LND2951 3 SD RESET + 1 F R2 Latch Off When Error Flag Occurs Low Drift Current Source * Linear Dimensions, Inc. * 445 East Ohio Street, Chicago IL 60611 USA * tel 312.321.1810 * fax 312.321.1830 * www.lineardimensions.com * |
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