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calogic LP2950 LP2951 handbook

1. INPUT VOLTAGE NOTE PULLUP RESISTOR TO SEPARATE 5V SUPPLY 0 0 2 3 4 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 200 UT VOLTAGE V OUTPUT LOW VOLTAGE V 1D 38 TIME us UT IMPEDANCE sh RIPPLE REJECTION RIPPLE REJECTION 00uA A RIPPLE REJECTION dB RIPPLE REJECTION dB OUTPUT IMPEDANCE OHMS l 10mA 20 0K 10 102 103 104 109 104 FREQUENCY H FREQUENCY Hz FREQUENCY Hz LOAD TRANISENT LOAD TRANSIENT LP2951 RESPONSE RESPONSE ENABLE TRANSIENT C 1pF CHANGE mV CHANGE mV OUTPUT VOLTAGE V NLO NO GO DN SHUTDOWN PIN VOLTAGE V m o LOAD CURRENT OUTPUT VOLTAGE LOAD CURRENT OUTPUT VOLTAGE 400 0 100 200 300 400 500 600 700 TIME ms TIME us 1D 45 CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 calogic 950 LP295 ERROR 1 2 TO 30V OUTPUT LP2
2. 50 25 0 25 50 75 100125150 100A 1mA 10mA TEMPERATURE C 1D 28 TEMPERATURE C 1D 29 OUTPUT CURRENT QUIESCENT CURRENT QUIESCENT CURRENT QUIESCENT CURRENT 5V OUTPUT 19 5V OUTPUT 8 QUIESCENT CURRENT uA QUIESCENT CURRENT mA QUIESCENT CURRENT mA 50 7 75 50 25 0 25 50 75 100125150 75 50 25 0 25 50 75 100125 150 2 3 5 6 TEMPERATURE C 1031 TEMPERATURE C 1032 INPUT VOLTAGE V CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 950 LP295 calogic TYPICAL PERFORMANCE CHARACTERISTICS continued LP2951 MINIMUM LP2951 FEEDBACK LP2951 FEEDBACK OPERATING VOLTAGE BIAS CURRENT PIN CURRENT PIN 7 DRIVEN BY EXTERNAL SOURCE REGULATROR RUN OPEN LOOP Ta 125 FEEDBACK CURRENT pA MINIMUM OPERATING VOLTAGE V BIAS CURRENT nA 1 6 75 50 25 0 25 50 75 100125150 75 50 25 0 25 50 75 100125150 B 0 05 1 0 TEMPERATURE C 1D 34 TEMPERATURE C 1D 35 FEEDBACK VOLTAGE V 1D 36 LP2951 ERROR LP2951 COMPARATOR LINE TRANSIENT COMPARATOR OUTPUT SINK CURRENT RESPONSE CHANGE OUTPUT VOLTAGE SINK CURRENT mA COMPARATOR OUTPUT V
3. must be used for the condition of 100mA load at 1 23V output The LP2950 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 applications like CMOS RAM keep alive circuits When setting the output voltage of the LP2951 version with external resistors a minimum load of 14A 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 1uA tantalum or aluminum electrolytic capacitor should be placed from the input to the ground Instability can occur if there is a stray capacitance to the LP2951 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 eliminated by adding a 100pF capacitor between output and feedback and increasing the output capacitor to at least 3 3uF ERROR DETECTION COMPARATOR OUTPUT The Comparator produces a logic low output whenever the LP2951 output falls out of regulation by more than around 5 This occurs at approximately 60mV offset divided by the 1 235 reference voltage This trip level remains 5 below normal regardless of the programmed output voltage of the regulator Figure 1 shows the timing diagram depicting the ERROR signal and the regulator output voltage as the LP2951 input is ramped up and down The ERROR s
4. 10Hz to 100KHz Reference Voltage CL 1pF CL 200uF CL 13 3uF Bypass 0 01uF pins 7 to 1 LP2951 Reference Voltage Over Temperature Note 6 Feedback Pin Bias Current Reference Voltage Temperature Coefficient Note 7 Feedback Pin Bias Current Temperature Coefficient CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 CORPORATION LP2950 LP2951 calogic ELECTRICAL CHARACTERISTICS continued LP2951 LP2950AC LP2951AC LP2950C LP2951C CONDITIONS PARAMETER NIT PARAMETER MIN TYP MAX MIN TYP MAX MIN TYP MAX 5 Note 2 ERROR COMPARATOR Output Leakage Current Vou 30V Output Low Voltage Vin 4 5V lo 400A Upper Threshold Voltage Note 7 Lower Threshold Voltage Note 7 Hysteresis Note 7 SHUTDOWN INPUT Low Regulator ON High Regulator OFF Shutdown Pin Vs 2 4V Input Current Vs 30V Regulator Output Current in Shutdown Input Logic Voltage Note 9 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 guaranteed for Ty 25 C Vin 6V IL 100uA and CL 1uF Additional conditions for the 8 pin versions are feedback tied to 5V tap and output tied t
5. 5432 IN4001 A LP2951 LP2951 0 1 uF 5V gt OUTPUT IN457 W LOAD 50mA TO 300mA MIN VOLTAGE 4V OPEN CIRCUIT DETECTOR FOR 4mA TO 20mA CURRENT LOOP 300mA REGULATOR WITH 0 75 DROPOUT CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 950 LP295 calogic SCHEMATIC DIAGRAM R21 82 SHDN DENOTES CONNECTION ON LP2950 ONLY CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025
6. 951 SHUTDOWN INPUT 2 INPUT VOLTAGE SEE APPLICATION INFO FIGURE 1 ERROR OUTPUT TIMING FIGURE 2 ADJUSTABLE REGULATOR Vour Vin OUTPUT LP2951 LP2951 SHUTDOWN MINIMUM INPUT OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV DEPENDING ON LOAD CURRENT CURRENT LIMIT IS TYPICALLY 160mA LATCH OFF WHEN ERROR FLAG OCCURS WIDE INPUT VOLTAGE RANGE CURRENT LIMITER CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 950 LP295 calogic TYPICAL APPLICATIONS continued LP2951 MEMORY V 4 1 9 FOR 5 5V 1 UF LOW BATTERY DISCONNECT Vin ERROR LP2951 5 8V BATTERY OPTIONAL LATCH OFF WHEN DROPOUT OCCURS ADJUST R3 FOR C2 SWITCHING WHEN Vy IS 6 0V OUTPUTS GO LOW WHEN Vy DROPS BELOW DESIGNATED THRESHHOLDS REGULATOR WITH STATE OF CHARGE INDICATOR CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 calogic 950 LP295 TYPICAL APPLICATIONS continued 10KQ AUX SHUTDOWN 5 DEGREE SHUTDOWN FLAG INPUT gt LP2951 EXTERNAL CIRCUIT PROTECTED FROM OVER TEMPERATURE V GOES OFF WHEN TEMP gt 125 SYSTEM OVER TEMPERATURE PROTECTION CIRCUIT UNREGULATED INPUT 2N
7. INPUT CURRENT 5V OUTPUT GROUND PIN CURRENT mA OUTPUT VOLTAGE VOLTS INPUT CURRENT uA 1 0 10 2 3 4 5 23 45 6 7 8 9 10 LOAD CURRENT mA NPUT VOLTAGE VOLTS INPUT VOLTAGE VOLTS 1D 24 OUTPUT VOLTAGE vs TEMPERATURE OF 3 INPUT CURRENT ae REPRESENTATIVE UNITS QUIESCENT CURRENT 0 5V OUTPUT 5V OUTPUT x 5V OUTPUT R 500 a o ER eo o Dy A re INPUT CURRENT mA OUTPUT VOLTAGE V oa eo QUIESCENT CURRENT uA A o 4 94 2345 6 7 8 9 10 75 50 25 0 25 50 75 100125 150 2 3 4 5 6 INPUT VOLTAGE VOLTS 10 25 TEMPERATURE C 10 26 T VOLTAGE VOLTS i SHORT CIRCUIT CURRENT DROPOUT VOLTAGE Bob POUT VOLTAGE 160 400 150 300 140 130 200 120 100 DROPOUT VOLTAGE mV DROPOUT VOLTAGE mV 110 SHORT CIRCUIT CURRENT mA 100 0 0 75 50 25 0 25 50 75 100125150 75
8. O O LP2950AC 1 O calogic CORPORATION FEATURES 5V 3 3V and 3 0V Versions at 100mA Output Very Low Quiescent Current Low Dropout Voltage Extremely Tight Load and Line Regulation Very Low Temperature Coefficient Current and Thermal Limiting Needs Only 1uF for Stability LP2951 Versions Only Error Flag Warns of Output Dropout 9 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 Consumer Equipment 9 Portable Instrumentation Avionics SMPS Post Regulator 9 Voltage Reference Automotive Electronics PIN CONNECTIONS 8 PIN SURFACE MOUNT 100mA Low Dropout Voltage Regulators LP2950 LP2951 PRODUCT DESCRIPTION The Calogic LP2950 and LP2951 are low power voltage regulators These devices are an excellent choice for use in battery powered applications such as cordless telephones radio control systems and portable computers The LP2950 and LP2951 features very low quiescent current and very low dropout voltage Typ 50mV at light load and 380mV at 100mA This includes a tight initial tolerance of 0 596 typ extremely good load and line regulation 0 05 typ and very low output temperature coefficient making the LP2950 LP2951 useful as a low power voltage reference The error flag output f
9. a Ma oce cAT he tints cushy 55 to 150 C LP2950AC LP2950C LP2951AC LP2951C 02 40 to 125 C CORPORATION Input Supply Voltage 0200 08 0 3 to 30V Feedback Input Voltage lusus 1 5 to 30V Shutdown Input Voltage 008 0 3 to 30V Error Comparator Output 0 3 to 30V ESD RAllg iere mE esate et ki 2KV Min ELECTRICAL CHARACTERISTICS Vs 15V Ta 25 C unless otherwise specified CONDITIONS LP2951 LP2950AC LP2951AC LP2950C LP2951C PARAMETER MIN TYP MAX MIN TYP MAX MIN TYP MAX 3V VERSIONS Output Voltage Note 2 Ty 25 C 25 C lt Ty lt 85 C Full Operating Temperature Output Voltage 3 3V VERSIONS Output Voltage 100uA lt IL lt 100mA TJ lt TJMAX Ty 25 C 25 C lt Ty lt 85 C Full Operating Temperature Output Voltage 5V VERSIONS Output Voltage 100uA lt IL lt 100mA Ty lt TJMAX Ty 25 C 25 C lt Ty lt 85 C Full Operating Temperature Output Voltage ALL VOLTAGE OPTIONS Output Voltage Temperature Coefficient 100uA lt IL lt 100mA Ty TJMAX Note 1 Line Regulation Note 3 6V lt Vin 30V Note 4 Load Regulation Note 3 100A x IL lt 100mA Dropout Voltage Note 5 IL 1004A IL 100mA Ground Current IL 1004A IL 100mA Current Limit Vout 0 Thermal Regulation Output Noise
10. eature is used as power on reset for warning of a low output voltage due to falling voltage input of batteries Another feature is the logic compatible shutdown input which enables the regulator to be switched on and off The LP2950 is offered in a 3 pin TO 92 package compatible with other 5V 3 0V 3 3V regulators The LP2951 is also available in 8 pin plastic and SO 8 The regulator output voltage may be pin strapped for 5V 3V or 3 3 volts or programmed from 1 24 volt to 29 volts with an external pair of resistors Use of AS s design processing and testing techniques make our LP2950 and LP2951 superior over similar products ORDERING INFORMATION PART PACKAGE TEMPERATURE RANGE LP2950ACN X TO 92 3 Pin IND LP2950CN X TO 92 3 Pin IND LP2951ACP X Plastic DIP 8 Pin IND LP2951CP X Plastic DIP 8 Pin IND LP2951ACS X Plastic SOIC 8 Pin IND LP2951CS X Plastic SOIC 8 Pin IND X 3 0V 3 3V or 5 0V OUTPUT SENSE SHUTDOWN GROUND LP2951 TOP VIEW INPUT 1 OUTPUT FEEDBACK 2 GROUND 3 INPUT 5V OR 3 3V TAP ERROR BOTTOM VIEW CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 ABSOLUTE MAXIMUM RATINGS Power Dissipation 0 Internally Limited Lead Temp Soldering 5 Seconds 260 C Storage Temperature Range 65 to 150 C Operating Junction Temperature Range EPBOSE Sik
11. ignal becomes low at around 1 3V input and goes high around 5V input input voltage at which Vout 4 75 Since the LP2951 s dropout voltage is load dependent the input voltage trip point around 5V will vary with the load current The output voltage trip point approx 4 75V does not vary with load CORPORATION The error comparator has an open collector output which requires an external pullup resistor Depending on the system requirements the resistor may be returned to 5V output or other supply voltage In determining the value of this resistor note that the output is rated to sink 400uA this value adds to battery drain in a low battery condition Suggested values range from 100K to 1MQ If the output is unused this resistor is not required PROGRAMMING THE OUTPUT VOLTAGE OF LP2951 The LP2951 may be pin strapped for 5V using its internal voltage divider by tying Pin 1 output to Pin 2 sense and Pin 7 feedback to Pin 6 5V Tap Also it may be programmed for any output voltage between its 1 235V reference and its 30V maximum rating As seen in Figure 2 an external pair of resistors is required Refer to the equation below for the programming of the output voltage Vout Vrer x 1 R1 R2 lFBR1 The Vrer is 1 235 and lrg is the feedback bias current nominally 20nA The minimum recommended load current of uA forces an upper limit of 1 2MQ on value of Re If no load is presented the Irg produces an error of typicall
12. inal 7 596 guaranteed Note 8 VsuurbowN 2 2V Vin 30V Vout 0 Feedback pin tied to 5V Tap Note 9 All typical values are not guaranteed BLOCK DIAGRAM UNREGULATED DC gt 5V 100mA 7 8 MAX K FROM AMPLIFIER OR TTL gt ERROR DETECTION TO CMOS OR 1 23V COMPARATOR O ONOS OI TTL REFERENCE LP2950 AND LP2951 BLOCK DIAGRAM CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 APPLICATION HINTS EXTERNAL CAPACITORS The stability of the LP2950 LP2951 requires a 1 0uF or greater capacitor between output and ground Oscillation could occur without this capacitor Most types of tantalum or aluminum electrolytic are acceptable For operations below 25 C a solid tantalum is recommended since the many aluminum types have electrolytes that freeze at about 30 C The ESR of about 5Q or less and resonant frequency about 500kHz are the most important parameters in the value of the capacitor The capacitors value may be increased without limit At lower values of output current less output capacitance is required for stability For currents below 10mA the value of the capacitor can be reduced to 0 33uF and 0 1uF for 1mA More output capacitance is needed for the 8 pin version at voltages below 5V since it runs the error amplifier at lower gain At worst case 3 3uF or greater
13. o output Sense Vout 5V and VsuurbowN x 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 LP2951 is tested at 150 C for IL 1mA For IL 100uA and Ty 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 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 input account Note 6 Vner lt Vout lt Vin 1V 2 3 lt Vin 30V 100HA lt IL 100mA Ty Tumax 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 95mV x 5V 1 235 384mV Thresholds remain constant as a percent of Vour as Vout is varied with the dropout warning occurring at typically 5 below nom
14. y 2 in Vout which may be eliminated at room temperature by trimming R1 To improve the accuracy choose the value of R2 100k this reduces the error by 0 1796 and increases the resistor program current by 12uA Since the LP2951 typically draws 60uA at no load with Pin 2 open circuited this is a small price to pay REDUCING OUTPUT NOISE It may be an advantage to reduce the AC noise present at the output One way is to reduce the regulator bandwidth by increasing the size of the output capacitor This is the only way that noise can be reduced on the lead 3 of LP2950 but is relatively inefficient as increasing the capacitor from 1uF to 220uF only decreases the noise from 430uV to 160uVrms for a 100kHz bandwidth at 5V output Noise could also be reduced fourfold by a bypass capacitor across Rj since it reduces the high frequency gain from 4 to unity Cpypass 1 2nR1 x 200Hz or choose 0 01uF When doing this the output capacitor must be increased to 3 3uF to maintain stability These changes reduce the output noise from 430uV to 100uVrms for a 100kHz bandwidth at 5V output With the bypass capacitor added noise no longer scales with output voltage so that improvements are more dramatic at higher voltages CALOGIC CORPORATION 237 Whitney Place Fremont California 94539 Telephone 510 656 2900 FAX 510 651 3025 LP2950 LP2951 calogic 950 LP295 TYPICAL PERFORMANCE CHARACTERISTICS DROPOUT QUIESCENT CURRENT CHARACTERISTICS

calogic LP2950 LP2951 handbook

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