o LP2950/LP2951 150mA Low Drop Out Voltage Regulators (PRODUCT DESCRIPTION he Semiconductor LP2950 and LP2951 .are a low power voltage regulators. These devices are excellent choice for use in battery- powered applications such as cordless telephone, radio control systems, and portable computers. The LP2950 and LP2951 features very low quiescent current (75, A Typ.) and very low drop output voltage (Typ. 40 V at light load and 380 mV at 100 mA).This includes a tight initial tolerance of 0.5% 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. Other key additional feature of this unregulated input voltage transient of -20V below ground (reverse battery). The error flag output feature is used as power-on reset for warn of a. low output voltage , due to following batteries on input. Other feature is the logic-compatible shutdown input which enable the regulator to be switched on and off. The LP2950 is offered in 3-pin TO-92 package compatible with other 5 volt regulators. The LP2951 is available in 8-pin plastic, SOP-8 package. The regulator output voltage may be pin-strapped for a 5 volt of programmed from 1.24 volt to 29 volts with external pair of resistors. Using of as design, processing and testing techniques make our LP2950 and LP2951 superior over similar products. (FEATURES ) (APPLICATIONS ) * Output accuracy 5V, 150 mA output : Battery powered systems Very low quiescent current e Cordless telephones Radio control systems Portable/Palm top / Notebook computers e Portable consumer equipment Portable instrumentation * Avionics Low dropout voltage Extremely tight load and line regulation Very low temperature coefficient Needonly 1, F for stability Unregulated DC input can withstand -20V reverse battery and +60V positive transients e Direct replacement for LP2950/LP2951 sockets * Automotive Electronics e SMPS Post-Regulator e Voltage Reference (Lp2951 VERSIONS ONLY ) PIN 1. OUTPUT e Error Flag warns of output dropout TO-92 2. SENSE . . 3. SHUTDOWN = Logic-Controlled electronic shutdown 4. GROUND Output programmable from 1.24 to 29V Q : Sen op 7. FEEDBACK ORDERING INFORMATION 8.. INPUT 4 TO-92 PLASTIC OPER. y 8 SOP 3-PIN SOP TEMP. 8-PIN RANGE. PIN 1. OUTPUT LP2950ACT IND. 2. GND 8 Sa LP2950CT IND. 3. INPUT 1 LP2951ACS IND. LP2951CS IND. 3-1FE deo ricnisce LP2950/LP2951 150mA Low Drop Out Voltage Regulators (ABSOLUTE MAXIMUM RATINGS J Power Dissipation............-6:0+ Internally Limited Lead Temp.(Soldering, 5 Seconds)................ 260% Storage Temperature Range............. 65 to +1507 Operating Junction Temperature Range LP 295 Doe eee eee eeneeeenees 55 to +150 LP2950AC/LP2950C LP29S51AC/LP295 1... cece -40 to +125 Input Supply Voltage... cree Feedback Input Voltage... Shutdown Input Voltage... eee Error Comparator Output. ECD Rating is to be determined -20 to +60V -1.5 to +30V -0.3 tot30V ELECTRICAL CHARACTERISTICS at V.=15V. Ta=25. unless otherwise noted. (Note 2) c -25% < Tra 85e Full Operating Teperature < is = pA k=! 00mA 1L=150mA = A 1L=100mA 1L=150mA =) out =O A u Ci=200n F Ci=13.3n F (Bypass=0.01, F pins 7 to Temperature Coefficient Current Temperature Coefficient Min. 4.975 4.95 4.94 4.93 LP2851AC T 3.0 LP2351C T 5.0 Max 5.05 5.075 5 5 3-2o LP2950/LP2951 150mA Low Drop Out Voltage Regulators CONDITIONS LP2950AC LP2950C PARAMETER LP2951AC LP2951CG UNITS (Note2) Min. Typ. Max. Min. Typ. Max. ERROR Comparator Output Leakage Current Von=30V 0.01 1 1 pA Output Low Voltage Van = 4.5V 150 250 150 250 mV Ly. = 400, A Upper Threshold Voltage | (Note 8) 40 60 40 60 mV Power Threshold Voltage | (Note 8) 75 95 75 95 mvV Hysteresis (Note 8) 15 15 mV Shutdown Input Output Logic Voltage Low (Regulator ON) 1.3 0.7 1.3 0.7 Vv . : High(Regulator OFF) 2 2 Shut down Pin Input Vs =2.4V 30 50 30 50 pA Current Vs = 30V 450 600 450 600 Regulator Output Current | (Note 9) 3 10 3 10 whA in Shutdown 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 T=25e, Va =6V,=100,. A and C.=100, F. Additional conditions for the 8-pin versions are feedback tied to 5V tap output Sense (Vout =5V)and Vinudown <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 convered under the specification for thermal regulation. Note 4:Line regulation for the LP2951 is tested at 150 for I=lmA-For 1,=100, A and Tj=125%, 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 value of programmed output voltage , the minimum input supply voltage of 2V (2.3V over temperature) must be taken in to account . Note 6: 9 Veer < (Vin-1V),2.3 < Vin <30V, 100, A<J,<100mA, T;< Tnx. Note 7: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. <= Vow Note 8: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the To express these thresholds in terms of output voltage change , multiply by the gain=Vout/Vref=(R1+R2)/R2.For programmed output voltage of SV, the Error nominal reference voltage measured at 6V input . error amplifier example, at a output is guaranteed to go low when the output drops by 95 mV X 5V/1.235=384mV. Thresholds remain constant as a percent of Vout as Vout is varied. with the dropout waming occurring at typically 5% below nominal, 7.5% guaranteed. Note 9:Vuuidown2 2V, Vin <30V,Vout =0, Feedback pin tied to SV Tap. . 3-3o LP2950/LP2951 150mA Low Drop Out Voltage Regulators (APPLICATION HINTS EXTERNAL CAPACITORS External Capacitors For the stability of the LP2950/LP2951 requires a 1.0 F or greater capacitor between output and ground. Oscillation could occur without this capacitor. The tantalum or aluminum electrolytic works fine; could use the fiLP type but are not cost efficient. For the operation of below -25% solid tantalum is recommended since the many aluminum type have electrolytes the freeze at about -30%. The ESR of about 5Q or less and resonant frequency above 500kHz are most important parameter in the value of Capacitor. The Capacitors value can be increased without any limit. At lower values of output current, less output capacitance is required for stability. For the currents below 10 mA the value of capacitor can be reduce to 0.33, F and 0.14 F for lmA. More output capacitance needed for the 8-pin version at voltage below 5V since it runs the error amplifier at lower gain. At worst case 3.3, F or greater must be used for condition of 100mA load at 1.235V output . The LP2950 not like other low dropout regulators will remain stable and regulation with no load in addition to the internal voltage divider. This feature very important in application like CMOS RAM keep-alive. The LP2951 output voltage setting with minimum load of 1 A and external resistors. Ifat the input of LP2950/LP 2951 connected to battery or between AC filter capacitor and input is 10 inches wire then I F tantalum or aluminum electrolytic capacitor should be connected between input and ground . Instability can occur if stray capacitor to feedback terminal pin 7 of the LP2951. This could cues more problem more when using higher value of external to set the output voltage . To fix this problem the 100 pF capacitor between output and feedback and increasing output capacitance to 3.3 F. {ERROR DETECTION COMPARATOR OUTPUT The Compactor produces a logic low output whenever the LP2951 output falls of regulation by more than around 5% . This is around 60 mV offset divided by the 1.235 reference voltage. Thus trip remains 3% below nominal regardless of the programmed output voltage of the regulator . the 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 signal becomes low at around 1.3 V input , it goes high around 5Volt input , (input voltage at which Vout = 4.75). The LP2951 dropout voltage depending on the load , the input voltage trip point around 5 volt will vary with load current. The output voltage trip point is around 4.75 volt it does not change with load. The error comparator has an open-collector output which requires an external pull-up __ resistor. ) Depending oon the = system requirement the resistor maybe returned to 5 volt output or other supply voltage depending to the system requirements. For determining the size of the resistor, note that the output is sinking 400, A , this value adds to battery drain in a low better condition, recommended values 100K to 1MaQ. If the output is unused this resistor is not required. 3-4 o LP2950/LP2951 150mA Low Drop Out Voltage Regulators (PROGRAMMING THE OUTPUT VOLTAGE OF _LP2951 The LP2951 programmable for any value from output voltage is its reference voltage of 1.235 volt and it maximum rating of 30 volt . For example for 5 volt needs to pin- strapped and using the internal voltage divider by tying pin | to 2 and pin7 to pin 6. Refer to Figure 2, there are two external resistor required for this programming . Refer to the below equation for the programming the output voltage: Volt = Vier x (1+R)\R2)+] Ri The Vrr is 1.235 and Ipg is the feedback bias current , nominally - 20 nA. The minimum recommended load current of 1, A forces an upper limit of 1.2Mn on value of R2, If no load presented the Irp produces error of typically 2% in Vout which maybe eliminated at room temperature by trimming R, . To improve the accuracy chooses the value of R2 =100K and this reduces the error by 0.17% and the program current by 12 . A . The LP2951 typically draw 60 yA at no load with pin 2 open-circuit,and this increases resistor value does not look much . ) (REDUCING OUTPUT NOISE It could be an advantage to reduce the AC noise present at the output One way is to reduce the regulator bandwidth by increasing the value of the output capacitor . this is the only method that noise could reduce on the LP 2950 but is relatively the noise from 430, V to 160 pV mms . for a 100 kHz bandwidth at 5 volt output . Noise could be also reduce by fourfold by a bypass capacitor across the high frequency gain from 4 to unity . pick R, since it reduces the output must be increased to 3.3 F to maintain Stability .-These-changes the output noise from 430 V mms . for a 100 kHz bandwidth 5 volt output . With the bypass capacitor added , noise no capacitor longer scales with output voltage so ) inefficient , as increasing capacitor CBYPASS = 1/22 RI x 200Hz or that improvements are more from 14, F to 220, F only decreases choose 0.01 . F . When doing this; dramatic higher output voltage . +ViIN 4.78V 3 OUTPUT 100K Vout VOLTAGE ERROR 5 VIN Ll 1.2-30V v v OUTPUT ERROR four, + = ERROR NOT NOT LP2951 bo VALID VALID G a i ical SHUTDOWN al sp uP INPUT : GND Fe VOLTAGE 1.39 OFF - 1,.23V on > "SEE APPLICATIONS INFORMATION - . VREF 3 NOTE:PINS 2 AND 6 ARE LEFT OPEN | a FIGURE 1. ERROR Output Timing FIGURE 2.Adjustable Regulator 3-5FC) . L.P2950/LP2951 150mA Low Drop Out Voltage Regulators Semiconductor (BLOCK DIAGRAM AND TYPICAL APPLICATIONS UNREGULATED DC Sv + | 7 8 1 = [- ")FEEDBACK[ | INPUT [~ OUTPUT I I" = | | [3 182K. Gs ai mon CMOS Ssmed O OWN AMPLIFIER T 60mV TTS = | Y_- ERROR | 1.206v. ae a DETECTION | Ty COMPARATOR LW Sao ye ~ 1 Sut 150mA MAX, 330K TO CMOS OR TTL 3-6FE Moricnicce LP2950/LP2951 150mA Low Drop Out Voltage Regulators Typical Performance Characteristics Input Current q z = 3 5 z INPUT VOLTAGE(V} Short Circult Current as ato 350 100 250 200 SHORT CIRCUIT CURRENT (mA} TEMPERATURE(C) Ground Pin Current 2 QUIESCENT CURRENT e a = o1 1 to 100 LOAD CURRENT(mA) Ground Pin Current QUIESCENT CURRENT (uA) 76 -60 -28 6 25 80 78 100 128 150 TEMPERATURE(C) Output Voltage vs. Temperature of 3 Representative Unite OUTPUT VYOLTAGE() a -75 ~80-25 0 25 $0 753.100 125 150 TEMPERATURE('C) Dropout Voltage 600 Lalstms S & x 400 g a00 o > 5 100 oO 3 zs a 3 30 75 180 TEMPERATURE(C} Dropout Characteristics 6 OUTPUT VOLTAGE() e 0 1 2 a 4 5 INPUT VOLTAGE(V} Ground Pin Current QUIESCENT CURRENT(ma) 4 -75 -30-33 0 25 80 75) 100 125 150 TEMPERATURE(C) DROPOUT VOLTAGE (mV) QUIESCENT CURRENT(/A) INOVT CURRENT (cA) QUIESCENT CURRENT(ma) Ground Pin Current 140 o 123 4 5 6 7 8 INPUT VOLTAGE() Dropout Voltage at 1 10 100 OUTPUT CURRENT(ma) input Current Riw6oKa 9 : 2 3 4 5&5 6 7 B8 8 10 INPUT VOLTAGE () Ground Pin Current 0 o 12 39 4 5 @ 7 8 INPUT VOLTAGE(Y) 3-7FCI ; LP2950/LP2951 150mA Low Drop Out Voltage Regulators Semiconductor Typical Performance Characteristics Shutdown Threshold Voltage Line Regulation Maximum Rated Output Current S wp S 8~PIN SOP 2 E SOLDEERED a = _ TO PC BOARD 3 8 = Tr wx o125C > z E VormaSV = E Tamds'c 3 8 z = ta = g g > z 5 : 3 5 ; : 5 5 o Q a -75 -00 -25 0 25 50 75 100 125 150 10 15 20 30 5 10 16 = 2 be TEMPERATURE(C) INPUT VOLTAGE(V} Input Voltege(V) Load Transient Response Load Transient Response Enable Transient _ 7 00 ta > oO Co 3r zs ee ES iG 28 Be 4 >t aa o 2 > re S : gs 5 = Vn w8 Cr 215, a ores z8 ! Chetdur Voorss & e a & a a8 re ES 2 se 3 az e oO oO Ou ~2 o 2 4 a8 10 o 4 a 12 18 20 7 TIMES(mS) TIMES(mS) TINES( 4S) Error Comparator Output Comparator Sink Current Line Transient Response iy vr y T g mY > YouT=sV 5 E 6 28 av E. a Z oe 2 _ o e E Cod 7 we Fay (kwima S. HYSTERESIS = vauusy = B av o x ta Za Zz Bg av 6 PULLUP RESISTOR TO a BS SEPARATE 5 SUPPLY =o -2 1 L 1 > wv Qo 1 2 3 4 & & 0.0 01 620.3 04 06 06 0.7 0.8 09 INPUT VOLTAGE(V) , : OUTPUT LOW VOLTAGE(Y) TE (+8) Minimum Operating Voltage Feedback Bias Current Feedback Pin Current ~ 22 20 50 = PIN 7 DRIVEN BY EXTERNAL = SOURCE (REQULATOR RUN gat 10 fF OPEN Loop) < 3 2.0 = 2 50 | t Eo & Tam 125C z 1 5 = -100 ZA = > i st oy a 14 P & 180 be Tewasic 3 re) a B _200 T=-66C z . |_| 2 ~76 60-25 C0 26 60 76 100 126 160 -76 -80 0 2 SO 76 100 125 160 ears 15-10 90.5 a 06 10 TEMPERATURE('C) TEMPERATURE(C) FEEDBACK VOLTAGE(V) 3-8