• DATA SHEET LND2950 / LND2951 100mA Low Dropout Voltage Regulators GENERAL DESCRIPTION FEATURES 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 (75µA 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. • • • • • • • • • • 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 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 1µF 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 *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 260º -65ºC to+150ºC -55ºC to +150º -0.3 to+30V -1.5 to+30V -0.3 to +30V -0.3 to +30V PIN CONFIGURATION Output 1 8 Input Sense 2 7 Feedback GND INPUT OUTPUT LND2951-XX Shutdown 3 6 -XX V tap GND 4 5 Error 8-Pin Plastic (Top View) TO-92 (Bottom View) +V IN 100kΩ ERROR OUTPUT 8 VIN 5 1 0.01µF LND2951 SHUTDOWN 3 INPUT Off V OUT 1.2 30V V OUT ERROR + 3.3 µ F R1 GND 4 FB 7 On 1.23V 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 (TA=25 ºC, VIN=15V Unless otherwise noted) MIN TYP MAX 0.985 |Vo| 0.98 |Vo| VO 1.015 |Vo| 1.02 |Vo| 0.976 |Vo| VO 1.024 |Vo| 50 150 ppm/ºC VO+1V≤VIN ≤30V(Note 4) 100µA ≤IL ≤100mA IL= 100µA IL= 100mA IL= 100µA IL= 100mA 0.04 0.4 % 0.1 50 380 75 8 0.3 80 450 120 12 % Dropout Ground Current VIN =V0 =-0.5V,IL =100µA 110 170 µA Current Limit Thermal regulation Vout=0 160 0.05 430 160 100 200 0.2 mA %/W 1.235 1.26 1.285 40 Output Voltage Output Voltage Output Voltage Temperature Coefficient Line Regulation(Note 3) Load Regulation( Note3) Dropout Voltage(Note 5) Ground Current 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 Regulator Output current in Shutdown CONDITIONS (note 2) -25ºC ≤Tj ≤85ºC Full Operating Temperature 100µA ≤IL ≤100mA, TJ ≤ TJMAX (note 1) CL= 1µF CL=200µF CL= 3.3µF (Bypass=0.01µF pins 7 to 1 (LND2951-XX)) Over temperature(Note 6) 1.21 1.185 20 (note 7) Voh=30V Vin=4.5V,IOL=400µA (note 8) (note 8) (note 8) Low(Regulator ON) High (Regulator OFF) Vs= 2.4V Vs=30V (Note 9) Vout=5.0V 3.3V≤Vout<5.0V 2.0V≤Vout<3.3V 40 UNITS V mV µA mA µV rms V nA 50 ppm/ºC 0.1 nA/ºC 0.01 150 60 75 15 1.0 250 1.3 0.7 30 450 50 600 3 10 20 95 2 µA mV V µA 30 • 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 =25ºC, Vin=Vo +1V,IL=100µAand CL =1µF. 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 150ºCfor IL=1mA. For IL =100µA and Tj=125ºC, 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,100µA≤IL≤ 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 µF (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 µF 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 7 Unregulated DC + + INPUT 8 INPUT FEEDBACK Vout IL <= 100mA 1 OUTPUT 2 OUTPUT SENSE Vout IL <= 100mA + + - ERROR AMPLIFIER + See Application Hints From CMOS or TTL 6 ERROR AMPLIFIER 3 XX VTAP SHUTDOWN 330kΩ 5 + + 60 mV II 60k To CMOS or TTL ERROR + + 4 1.23 V Reference 1.23 V Reference + See Application Hints GROUND GROUND Error detection Comparator • 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 5V BUS +V IN 8 ERROR OUTPUT +V IN 5 1 *V OUT V +V IN IN V OUT ERROR *V OUT V 5V OUT LND29500Z-5.0 + 1 µF LND2951 SHUTDOWN 3 INPUT GND GND 4 FB 7 *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 IL LOAD 30V I = 1.23/R L +V IN 8 V 470k Ω + 1 µF R1 LND2951 FB 7 3 SD RESET V OUT 1 V OUT ERROR *V OUT V OUT +V IN 5 470kΩ 1 IN 8 GND 4 Latch Off When Error Flag Occurs R2 LND2951 SHUTDOWN 3 SD INPUT GND 4 1 µF FB 7 R 1% + 1 µF 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 •