www.fairchildsemi.com LP2951 Adjustable Micro Power Voltage Regulator Features Description • • • • • • • • The LP2951 is an adjustable micro power voltage regulator suitable for use in battery-powered systems. This regulator has various functions such as alarm which warns of a low output voltage, often due to falling batteries on the input, the external shutdown which enables the regulator to be switched on and off, current and temperature limiting. Low Quiescent Current Low Dropout Voltage Low Temperature Coefficient Tight Line and Load Regulation Guaranteed 100mA Output Current Internal Short Current & Thermal Limit Error Signals of Output Dropout (8 pin Versions only) External Shut Down ( 8-Pin Versions Only) 8-SOP 1 Internal Block Diagram [3] Rev. 1.0.3 ©2010 Fairchild Semiconductor Corporation LP2951 Absolute Maximum Ratings Parameter 2 Symbol Value Unit Input Supply Voltage VIN -0.3 ~ +30 V Power Dissipation PD Internally Limited W Thermal Resistance Junction-Air RθJA 127.5 °C/W Storage Temperature Range TSTG -65 ~ +150 °C Operating Junction Temperature Range TOPR -40 ~ +125 °C LP2951 Electrical Characteristics (Refer to the test circuit, Ta = 25°C, unless otherwise specified, ) Parameter Symbol Conditions Min. Typ. Max. Unit ALL VOLTAGE OPTIONS Output Voltage Temperature Coefficient ΔV/ΔT (Note1) - 50 - ppm/°C Line Regulation (Note2) ΔV (Vo + 1)V ≤ VIN ≤ 28V IL = 50mA - - 0.4 % Load Regulation (Note2) ΔV 100uA ≤ IL ≤ 100mA - - 0.3 % Dropout Voltage VD IL = 100uA - - 150 mV IL = 100mA - - 600 mV Ground Current IG IL = 100uA - - 140 uA Current Limit ICL IL = 100mA VO = 0V - - 7 mA 110 165 220 mA 8-PIN VERSIONS ONLY VREF VIN = (Vo + 1)V, IL = 100uA 1.235 1.26 1.285 V VREF (Note3) 1.225 1.26 1.295 V Output Low Voltage VOL VIN = (Vo - 0.5)V, IOL =400uA High Threshold Voltage VTH Low Threshold Voltage Reference Voltage ERROR COMPARATOR - 150 400 mV (Note4) 25 60 - mV VTL (Note4) - 75 140 mV VHYS (Note4) - 15 - mV Shutdown Threshold Range VSD (Note5) 0.6 1.3 2.0 V Shutdown Input Current ISD VSD = 2.4V - 30 100 uA VSD = 28V - 450 750 uA Hysteresis SHUTDOWN INPUT Note : 1. Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. 2. Regulation is measured at constant junction temperature , using pulse testing with a low duty cycle. 3. Vref ≤ Vout ≤ (Vin - 1V), 2.5V ≤ Vin ≤ 28V, 100uA ≤ IL ≤ 100mA, TA ≤ TAMAX . 4. Threshold and hysteresis are expressed in terms of voltage differential at the Feedback terminal below the normal reference . To express these thresholds in terms of output voltage change , multiply by the error amplifier gain = VO / VREF = (R1 + R2) / R2 . 5. Vshutdown ≤ 0.6 V , VOUT =ON , Vshutdown ≥ 2.0 V, VOUT = OFF. 3 LP2951 Typical Performance Characteristics 6 2.0 OUTPUT VOLTAGE(V) GROUND CURRENT(mA) 5 5V OUTPUT 1.6 1.2 0.8 0.4 RL=50Ω 3 2 1 0 0.1 1 10 100 0 1 2 4 5 6 Figure 2. Dropout Characteristics Figure 1. Quiescent Current 250 120 RL=50Ω 5V OUTPUT 100 200 RL=50K INPUT CURRENT(mA) INPUT CURRENT(uA) 3 INP UT VO L T AG E (V) LOAD CURRENT(mA) 150 100 RL=∞ 50 80 60 40 20 0 0 0 2 4 6 8 10 0 2 4 Figure 3. Input Current 8 10 Figure 4. Input Current 5.06 20 0 5V OUTPUT SHORT CIRCUIT CURRENT(mA) 5.04 6 INPUT VO LT AG E(V ) INPUT VOLTAGE(V) OUTPUT VOLTAGE(V) RL=50KΩ 4 5.02 5.00 4.98 4.96 18 0 16 0 14 0 12 0 4.94 -50 -25 0 25 50 75 100 o TEMPERATURE( C) Figure 5. Output Voltage vs. Temperature 4 125 10 0 -5 0 -25 0 25 50 75 T E M P E R A T UR E ( o C ) Figure 6. Short Circuit Current 1 00 12 5 LP2951 Typical Performance Characteristics (Continued) TYPICAL PERFORMANCE CHARACTERISTICS (Continued ) Fig. 8 Dropout Voltage Fig. 7 Dropout Voltage 600 500 IL = 100mA DROPOUT VOLTAGE(mV) DROPOUT VOLTAGE(V) 500 400 300 200 0 -50 -25 0 25 50 75 o TEMPERATURE( C) Figure 7. Dropout Voltage 100 300 200 o TJ = 25 C 100 IL = 100μ A 100 400 125 0 0.1 1 10 100 OUTPUT CURRENT(mA) Figure 8. Dropout Voltage 5 LP2951 Typical Application VIN 8 VIN ERROR SHUTDOWN 5 ERROR V 1 OUT KA78RLOOD LP2951 3 SD GND 4 VOUT R1 FB Co 1μF 7 VREF R2 V O = VREF (1+ R1/ R2)+IFB R1 CO is required between the output and ground for stability at output voltages of 5V or more. since IFB is controlled to less than 40nA, the error associated with this term is negligible in most applications. At lower output voltage, more capacitance is required. without this capacitance the part will oscillate. 6 LP2951 Mechanical Dimension Package Dimensions in millimeters 8-SOP MIN #5 6.00 ±0.30 0.236 ±0.012 8° 0~ +0.10 0.15 -0.05 +0.004 0.006 -0.002 MAX0.10 MAX0.004 1.80 MAX 0.071 3.95 ±0.20 0.156 ±0.008 5.72 0.225 0.41 ±0.10 0.016 ±0.004 #4 1.27 0.050 #8 5.13 MAX 0.202 #1 4.92 ±0.20 0.194 ±0.008 ( 0.56 ) 0.022 1.55 ±0.20 0.061 ±0.008 0.1~0.25 0.004~0.001 0.50 ±0.20 0.020 ±0.008 7 LP2951 Ordering Information Product Number Package Operationg Temperature LP2951CM 8-SOP -40 ~ +125°C DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. 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