LP2950/LP2951 100mA Low Dropout Voltage Regulators FEATURES APPLICATIONS • 5.0V and 3.3V Versions at 100mA Output • Very Low Quiescent Current • Low Dropout Voltage: 380mV at 100mA • Extremely Tight Load and Line Regulation • Very Low Temperature Coefficient • Current & Thermal Limiting • Need Only 1 µF for Stability • Offered in TO-92 (LP2950) & SOIC (LP2951) • Direct Replacement For LP2950/LP2951 • Battery Powered Systems • Cordless Telephones • Radio Control Systems • Portable/Palm Top/Notebook Computers • Portable Consumer Equipment • Portable Instrumentation • Avionics • SMPS Post-Regulator • Voltage Reference • Automotive Electronics LP2951 versions only • Error Flag Warns of Output Dropout • Logic-Controlled Electronic Shutdown • Output Programmable From 1.24 to 29V Now Available in Lead Free Packaging PRODUCT DESCRIPTION The 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 feature low quiescent current and low dropout voltage (typ. 50mV at light load and 380 mV at 100mA). This includes a tight initial tolerance (0.5% typ.), extremely good load and line regulation (0.05% typ.), and very low output temperature coefficient (20 ppm/¡C typ.), making the LP2950/LP2951 useful as a low-power voltage reference. The error flag output feature is used as a power-on reset for warning of a low output voltage, due to a falling input voltage. The logiccompatible shutdown feature enables the regulator to be switched ON and OFF. The LP2950 is offered in a 3-pin TO-92 package compatible with other 5V, 3.3V regulators. The LP2951 is available in an 8-lead SOIC package. Block diagram of LP2951 UNREGULATED DC 8 1 INPUT OUTPUT 7 + FEEDBACK 5V @ 100mA MAX 2 SENSE + _ FROM CMOS OR TTL 3 180kΩ 6 ERROR AMPLIFIER 330kΩ 5V TAP SHUTDOWN + 60kΩ 60 mV + 5 ______ + _ + 1.23V ERROR ERROR DETECTION COMPARATOR 1µF . . TO CMOS OR TTL 4 REFERENCE Rev. 8/10/01 GROUND LP2950/51 100mA Low Dropout Voltage Regulators 1 ©Copyright 2001 Sipex Corporation LP2950/51 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 -40C to +125C Input Supply Voltage..................................... -0.3V to +30V 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 VIN=6V, IO=100µA, COUT=1µF (Note 2) TA=25C, unless otherwise noted. PARAMETER 3.3 V Versions Output Voltage Output Voltage 5 V Versions Output Voltage Output Voltage CONDITIONS TJ = 25¡C -25¡C ≤TJ ≤85¡C Full Operating Temperature 100 µA ≤IL ≤100 mA TJ ≤TJMAX TJ = 25¡C -25¡C ≤TJ ≤85¡C Full Operating Temperature 100 µA ≤IL ≤100 mA TJ ≤TJMAX LP2950AC LP2951AC Min. Typ. Max. Min. LP2950C LP2951C Typ. Max. UNITS 3.284 3.267 3.260 3.3 3.3 3.3 3.317 3.333 3.340 3.267 3.251 3.234 3.3 3.3 3.3 3.333 3.350 3.366 V 3.254 3.3 3.346 3.221 3.3 3.379 V 4.975 4.950 4.940 4.925 5.0 5.0 5.0 5.0 5.025 5.050 5.060 5.075 4.950 4.925 4.900 4.880 5.0 5.0 5.0 5.0 5.050 5.075 5.100 5.120 V 20 120 50 150 ppm/¡C V All Voltage Options Output Voltage Temperature Coefficient Line Regulation (Note 3) (Note 1) 6V ≤VIN ≤30V (Note 4) 0.03 0.1 0.04 0.2 % Load Regulation (Note 3) 100 µA ≤IL ≤ 100 mA 0.04 0.1 0.1 0.2 % Dropout Voltage (Note 5) IL = 100 µA IL = 100 mA IL = 100 µA IL = 100 mA 50 380 80 450 50 380 80 450 mV mV 150 8 170 12 150 8 170 12 µA mA 150 200 150 200 mA 0.05 0.2 0.05 0.2 %/W Ground Current Current Limit VOUT = 0 Thermal Regulation Output Noise, CL = 1µF 430 430 µV rms 10Hz to 100KHz CL = 200 µF 160 160 µV rms CL = 3.3 µF, Bypass = 0.01µF from Pin 7 to Pin 1 (LP2951) 100 100 µV rms 8-Pin Versions only Reference Voltage Reference Voltage Feedback Pin Bias Current Rev. 8/10/01 Over Temperature (Note 6) 1.220 LP2951AC 1.235 1.250 1.210 LP2951C 1.235 1.260 V 1.190 1.270 1.185 1.285 V 40 60 40 LP2950/51 100mA Low Dropout Voltage Regulators 2 60 nA ©Copyright 2001 Sipex Corporation LP2950/51 PARAMETER 8-Pin Versions only (Continued) CONDITIONS (Note 2) Min. Reference Voltage Temperature Coefficient Feedback Pin Bias Current Temperature Coefficient Error Comparator LP2951AC Typ. Max. Min. LP2951C Typ. Max. UNITS 20 50 ppm/¡C 0.1 0.1 nA/¡C Output Leakage Current VOH = 30V 0.01 1 0.01 1 µA Output Low Voltage VIN = 4.5V IOL = 400µA (Note 7) 150 250 150 250 mV Upper Threshold Voltage Lower Threshold Voltage Hysteresis 40 60 (Note 7) 75 (Note 7) 15 40 95 60 75 mV 95 15 mV mV Shutdown Input Input logic Voltage Shut down Pin Input Current Regulator Output Current in Shutdown Low (Regulator ON) High (Regulator OFF) VS = 2.4V VS= 30V (Note 8) 1.3 0.7 2.0 1.3 0.7 30 675 3 50 800 10 2.0 30 675 3 50 800 10 V V µA µA 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 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 LP2951 is tested at IL = 1mA. For IL = 100 µA 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≤ 100mA, 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: All typical values are not guaranteed. The value could vary from lot to lot. Rev. 8/10/01 LP2950/51 100mA Low Dropout Voltage Regulators 3 ©Copyright 2001 Sipex Corporation LP2950/ LP2951 TYPICAL PERFORMANCE CHARACTERISTIC 10 250 6 225 R L= 3 R L =50kΩ 2 GROUND PIN CURRENT (mA) 4 R L = 50kΩ 175 150 125 100 RL = 8 INPUT CURRENT (µA) 200 8 OUTPUT VOLTAGE (VOLTS) 5 75 50 1 1 0.1 25 0 0 1 2 3 4 5 1 0 6 2 320 240 INPUT CURRENT (mA) GROUND CURRENT (µA) 280 I L = 1mA 200 160 IL= 0 120 80 40 1 2 3 5 6 7 8 4 5 0.01 0.1 9 10 6 7 R L =50 Ω VOUT = 5V 12 V IN = 6V I L = 100mA 8 4 1 2 3 4 5 6 7 8 -75 -50 -25 9 10 0 25 50 75 100 125 150 TEMPERATURE (ºC) INPUT VOLTAGE (VOLTS) Ground Current 100 16 0 INPUT VOLTAGE (VOLTS) 10 Quiescent Current 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 8 1 LOAD CURRENT (mA) Input Current Dropout Characteristics 0 4 INPUT VOLTAGE (VOLTS) INPUT VOLTAGE (VOLTS) 0 3 GROUND CURRENT (mA) 0 Ground Current Input Current 16 190 12 10 QUIESCENT CURRENT (µA) GROUND CURRENT (mA) 14 I L =100mA 8 6 4 170 V IN =6V I L =100uA 150 130 2 0 0 1 2 3 4 5 6 7 -75 -50 -25 8 INPUT VOLTAGE Ground Current Rev. 8/10/01 0 25 50 75 100 125 150 TEMPERATURE (ºC) Quiescent Current LP2950/51 100mA Low Dropout Voltage Regulators 4 ©Copyright 2001 Sipex Corporation LP2950/LP2951 TYPICAL PERFORMANCE CHARACTERISTICS (continued) 170 500 600 I L = 100mA 160 400 300 ~ ~ 100 50 I L = 100µA SHORT CIRCUIT CURRENT (mA) 400 DROP-OUT VOLTAGE (mV) 300 200 TJ = 25ºC 100 0 0 -75 -50 -25 0 25 50 100µA 75 100 125 150 1mA TEMPERATURE (ºC) 10mA 140 130 120 110 110 -75 -50 -25 100mA OUTPUT CURRENT Drop-Out Voltage 2.5 T A = 125ºC SINK CURRENT (mA) HYSTERESIS 2 0 50 mV 1.5 T A = 25ºC 1.0 T A = -55ºC 0.5 0.0 0 1 2 3 4 5 0 C L = 1µF I L = 1mA V OUT = 5V -50 mV ~ ~ 8V 6V PULLUP RESISTOR TO SEPARATE 5V SUPPLY -2 4V 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 INPUT VOLTAGE (V) 200 OUTPUT LOW VOLTAGE (V) Error Comparator Output 400 600 800 TIME(µs) LP2951 Comparator Sink Current 10 75 100 125 150 100 mV 2.0 4 25 50 Short Circuit Current V OUT = 5V 6 0 TEMPERATURE (ºC) Drop-Out Voltage 8 COMPARATOR OUTPUT (V) 150 INPUT OUTPUT VOLTAGE VOLTAGE CHANGE DROP-OUT VOLTAGE (mV) 500 Line Transient Response 90 90 80 80 I O = 1mA 2 I O = 100mA 1 0.5 V OUT = 5V C L = 1µF 0.2 0.1 0.05 70 IL = 0 60 50 40 I L = 100µA C L = 1µF V IN = 6V V OUT = 5V 30 0.02 RIPPLE REJECTION (dB) 5 RIPPLE REJECTION (dB) OUTPUT IMPEDANCE (OHMS) IO = 100µA 10 100 1K 10K FREQUENCY (Hz) Output Impedance Rev. 8/10/01 100K 1M I L = 1mA 60 50 40 30 20 0.01 70 C L = 1µF V IN = 6V V OUT = 5V I L = 10mA 20 10 1 10 2 10 3 10 4 10 5 10 10 1 6 FREQUENCY (Hz) Ripple Rejection 10 2 10 3 10 4 10 5 10 6 FREQUENCY (Hz) Ripple Rejection LP2950/51 100mA Low Dropout Voltage Regulators 5 ©Copyright 2001 Sipex Corporation LP2950/LP2951 TYPICAL PERFORMANCE CHARACTERISTICS (continued) 20 50 1.9 FEEDBACK CURRENT (µA) 2.1 0 -10 -20 -50 -25 0 25 50 -75 -50 -25 75 100 125 150 0 25 50 6 150 40 100 20 -50 C L = 1µF V OUT = 5V 100 mA 0 -20 C L = 10µF V OUT = 5V -40 -60 ~ ~ 100 µA 100 100 µA µA 2 3 4 5 0 4 8 12 16 T JMAX = 125 ºC 40 T A =25 ºC T A = 85 ºC 20 5 10 15 20 INPUT VOLTAGE (V) LP2950 Maxium Rated Output 25 I L = 10mA V IN = 8V V OUT = 5V 1 C L = 10µF 0 2 0 0 100 200 300 400 500 600 700 Enable Transient 120 100 30 DIP SOLDERED TO PC BOARD T JMAX = 125º C V OUT = 5V 300 200 100 80 60 T A = 25ºC 40 T A = 50ºC 20 0 0 0 2 TIME (us) OUTPUT CURRENT (mA) Vout=5V 60 3 8-PIN MOLDED PIN 2 TO PIN 4 RESISTANCE (kΩ) 80 4 -100 400 TO-92 PACKAGE 0.25" LEADS SOLDERED TO PC BOARD 100 5 20 Load Transient Response 120 1.0 C L = 1µF TIME (ms) Load Transient Response 0.5 -2 TIME (ms) Rev. 8/10/01 SHUTDOWN OUTPUT PINOUT VOLTAGE (V) VOLTAGE (V) 7 0 0 -0.5 LP2951 Feedback Pin Current 80 50 -1.0 FEEDBACK VOLTAGE (V) 60 1 -1.5 -2.0 250 0 T A = 55ºC -200 200 ~ ~ T A = 25ºC -150 75 100 125 150 LP2951 Feedback Bias Current LOAD OUTPUT VOLTAGE CURRENT CHANGE (mV) LOAD OUTPUT VOLTAGE CURRENT CHANGE (mV) LP2951 Minimum Operating Voltage -100 TA=1 25ºC -100 TEMPEATURE (ºC) TEMPERATURE OUTPUT CURRENT (mA) -50 -250 -30 1.7 -75 PIN 7 DRIVEN BY EXTERNAL SOURCE (REGULATOR RUN OPEN LOOP) 0 10 BIAS CURRENT (nA) MINIMUM OPERATING VOLTAGE (V) 2.3 -75 T A = 85ºC 0 -50 -25 0 25 50 75 100 125 150 0 TEMPERATURE (ºC) LP2951 Divider Resistance 10 15 20 25 30 INPUT VOLTAGE (V) LP2950 Maxium Rated Output Current LP2950/51 100mA Low Dropout Voltage Regulators 6 5 ©Copyright 2001 Sipex Corporation LP2950/LP2951 3.5 1.6 4 3.0 1.4 1.2 VOLTAGE NOISE SPECTRAL DENSITY (µV/Hz) 5 OUTPUT VOLTAGE CHANGE (mV) 1.8 2 0 -2 1.0 POWER DISSIPATION (W) SHUTDOWN THRESHOLD VOLTAGE (V) TYPICAL APPLICATIONS 0.8 0.6 -75 -50 -25 0 25 50 ~~ 1 1.25W C L = 220µF 2.0 1.0 10 20 30 40 50 10 2 TIME (µs) Shutdown Threshold Voltage C L = 3.3µF C BYP = 0.1µF 1.5 0.0 -1 TEMPERATURE (¼C) 10 3 10 4 10 5 FREQUENCY (Hz), C BYP =0.1uF Thermal Response Output Noise 80 30 I L = 50µA 25 20 70 I L = 100µA 15 T J = 150 ¼C 10 5 RIPPLE REJECTION (dB) OUTPUT VOLTAGE CHANGE (mV) C L = 1µF 2.5 0.5 0 0 75 100 125 150 I L = 100mA I L = 1mA 0 ~~ 10 5 0 T J = 125 ¼C I L = 100µA 60 I L = 100mA 50 40 C L = 1µF V IN = 6V V OUT = 5V 30 20 -5 10 -10 5 10 15 20 25 30 10 1 10 2 INPUT VOLTAGE (V) 10 4 10 5 10 6 FREQUENCY (Hz) Line Regulation Rev. 8/10/01 10 3 Ripple Rejection LP2950/51 100mA Low Dropout Voltage Regulators 7 ©Copyright 2001 Sipex Corporation LP2950/51 APPLICATION HINTS EXTERNAL CAPACITORS The stability of the LP2950/LP2951 requires a 1.0µF 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 below -25°C solid tantalum is recommended since the many aluminum types have electrolytes that 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 capacitors value may be increased without limit. remains 5% below normal regardless of the programmed output voltage of the regulator. 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 0.33µ F and 0.1µ F 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 3.3 µF or greater must be used for the condition of 100mA load at 1.23V output. The error comparator has an open-collector output, which requires an external pull-up 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 400µ A, this value adds to battery drain in a low battery condition. Suggested values range from 100K to 1MΩ. If the output is unused this resistor is not required. The LP2950/51 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. When setting the output voltage of the LP2950/51 version with external resistors, a minimum load of 1µA is recommended 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 below equation for the programming of the output voltage: 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 1.3V input, and goes high around 5V input (input voltage at which VOUT = 4.75). Since the LP2951Õs 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. 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 1µA tantalum or aluminum electrolytic capacitor should be placed from the input to the ground. VOUT = VREF × (1 + R1/R2)+ IFBR1 The VREF is 1.235 and IFB is the feedback bias current, nominally 20nA. The minimum recommended load current of 1 µA forces an upper limit of 1.2MΩ on value of R2. If no load is presented the IFB produces an error of typically 2% in VOUT which may be eliminated at room temperature by trimming R 1. To improve the accuracy choose the value of R2 = 100k this reduces the error by 0.17% and increases the resistor program current by 12µA. Since the LP2951 typically draws 60µA at no load with Pin 2 open-circuited this is a small price to pay Instability can occur if there is 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 fixed by adding a 100pF capacitor between output and feedback and increasing the output capacitor to at least 3.3 µF. 4.75V OUTPUT VOLTAGE \ 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 3 lead LP2950 but is relatively inefficient, as increasing the capacitor from 1µF to 220 µF only decreases the noise from 430µV to 160µVRMS for a 100kHz bandwidth at 5V output. Noise could also be reduced fourfold by a bypass capacitor across R 1, since it reduces the high frequency gain from 4 to unity. Pick _______ ERROR* +5.0V INPUT VOLTAGE +1.3V + CBYPASS ≅ 1 / 2πR1 × 200 Hz + or choose 0.01µF. When doing this, the output capacitor must be increased to 3.3µF to maintain stability. These changes reduce the output noise from 430µV to 100µVRMS 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 output voltages. * See Application Info. Figure 1. ERROR Output Timing 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 is around 60 mV offset divided by the 1.235 reference voltage. This trip level Rev. 8/10/01 9 LP2950/51 100mA Low Dropout Voltage Regulators 8 ©Copyright 2001 Sipex Corporation LP2950/LP2951 TYPICAL APPLICATIONS +V IN 100K 8 ERROR 5 OUTPUT +V IN ______ ERROR V OUT 1.2 to 30V 1 LP2951 SHUTDOWN SD INPUT + R1 3 FB GND 3.3µF .01µF 7 4 1.23V R2 V REF Figure 2. Adjustable Regulator +V IN 470kΩ 8 5 ______ ERROR +V +V IN +V IN IN V OUT 470kΩ V OUT 1 8 ERROR LP2951 5 OUTPUT ______ ERROR V OUT 1 *V OUT = V IN + 3 RESET R1 SD GND 4 LP2951 1µF FB SHUTDOWN 7 INPUT 3 SD GND 4 R2 *MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV to 400mV. DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 150mA Figure 3. Latch Off When Error Flag Occurs Rev. 8/10/01 FB 7 Figure 4. Wide Input voltage Range Current Limiter LP2950/51 100mA Low Dropout Voltage Regulators 9 ©Copyright 2001 Sipex Corporation LP2950/LP2951 TYPICAL APPLICATIONS (continued) + 6V SEALED LEADACID BATTERY SOURCE 1.5kΩ 120kΩ 8 1N457 +V IN FB SPX385 V OUT 1 MAIN V+ LP2951 MEMORY V+ SENSE 400kΩ FOR 5.5 V 3 2 1µF SD 100kΩ + GND 20kΩ NI-CAD BACKUP BATTERY 4 Figure 5. Low Battery disconnect 8 39kΩ .. 2 SENSE +VIN 5 ______ ERROR RESET - + 3 C4 + 1uF LP2951 SD FB 39kΩ .. 1% +VOUT = 5V 1 VOUT GND 4 100kΩ .. 7 TAP 6 100kΩ .. C1 6V LEADACID BATTERY 1% 1kΩ .. + <5.8V** 100kΩ .. C2 + 1% 1kΩ .. <6.0V** 100k Ω .. C3 + R3 1% <6.2V** 10k Ω .. 20k Ω .. * OPTIONAL LATCH OFF WHEN DROPOUT OCCURS. ADJUST R3 FOR C2 SWITCHING WHEN VIN IS 6.0V * OUTPUTS GO LOW WHEN V IN DROPS BELOW DESGNATED THRESHHOLDS Figure 6. Regulator with State-of Charge Indicator Rev. 8/10/01 LP2950/51 100mA Low Dropout Voltage Regulators 10 ©Copyright 2001 Sipex Corporation LP2950/LP2951 TYPICAL APPLICATIONS (continued) +V IN 8 3 AUX SHUTDOW INPUT 10K Ω. +V IN _______ ERROR SD OFF 5 DEGREE SHUTDOWN FLAG . LP2951 ON V OUT GND 1 FB 4 + TEMP SENSOR 5 EXTERNAL CIRCUIT PROTECTED FROM OVER TEMPERATURE (V+ GOES OFF WHEN TEMP > 125) 7 AS35 OR RELAY 8.2K Ω - Figure 7. System Over Temperature Protection +5V 4 UNREGULATED INPUT 4.7mA 20mA 8 OUTPUT 8 IN +V IN V OUT 1 330K Ω 27KΩ LP2951 1N4001 LP2951 0.1µF FB 7 5V 2 6 SENSE V TAP 2 GND 4 2N5432 (2) V OUT 1 FB GND 7 4 OUTPUT + 360K Ω 1N457 4.7µF LOAD 50mA TO 300 mA MIN VOLTAGE = 4V Figure 8. Open Circuit Detector for 4mA to 20mA Current Loop Rev. 8/10/01 Figure 9. 300mA Regulator with 0.75V LP2950/51 100mA Low Dropout Voltage Regulators 11 ©Copyright 2001 Sipex Corporation LP2950/LP2951 SCHEMATIC DIAGRAM Rev. 8/10/01 LP2950/51 100mA Low Dropout Voltage Regulators 12 ©Copyright 2001 Sipex Corporation LP2950/LP2951 PACKAGE DIAGRAM 8-Pin Surface Mount (S) TO-92 (N) 2 1 OUTPUT 1 SENSE 2 SHUTDOWN GROUND 8 INPUT ALPHA 7 FEEDBACK 3 AS293 6 5V or 3.3V Output 4 0 5 ERROR V 3 VIN OUT GROUND LP2950 Bottom View LP2951 Top View ORDERING INFORMATION Ordering No. Accuracy Output Voltage LP2950ACN-3.3 LP2950ACN-5.0 LP2950CN-3.3 LP2950CN-5.0 LP2951ACS-3.3 LP2951ACS-5.0 LP2951CS-3.3 LP2951CS-5.0 0.5% 0.5% 1% 1% 0.5% 0.5% 1% 1% 3.3V 5.0V 3.3V 5.0V 3.3V 5.0V 3.3V 5.0V Corporation Packages 3 lead TO-92 3 lead TO-92 3 lead TO-92 3 lead TO-92 8 Lead SOIC 8 Lead SOIC 8 Lead SOIC 8 Lead SOIC Now available in Lead Free. To order ad "-L" to the part number. Example: LP2950CN= Normal, LP2950CN-L = Lead Free SIGNAL PROCESSING EXCELLENCE Sipex Corporation Headquarters and Main Offices: 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: [email protected] 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 935-7600 FAX: (408) 934-7500 Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others. Rev. 8/10/01 LP2950/51 100mA Low Dropout Voltage Regulators 13 ©Copyright 2001 Sipex Corporation