SM72238 SolarMagic Micropower Voltage Regulator General Description Features The SM72238 is a micropower voltage regulator with very low quiescent current (75μA typ.) and very low dropout voltage (typ. 40mV at light loads and 380mV at 100mA). It is ideally suited for use in battery-powered systems. Furthermore, the quiescent current of the SM72238 increases only slightly in dropout, prolonging battery life. The SM72238 is available in the surface-mount D-Pak package. Careful design of the SM72238 has minimized all contributions to the error budget. This includes a tight initial tolerance (.5% typ.), extremely good load and line regulation (.05% typ.) and a very low output voltage temperature coefficient, making the part useful as a low-power voltage reference. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Renewable Energy Grade High accuracy output voltage Guaranteed 100mA output current Extremely low quiescent current Low dropout voltage Extremely tight load and line regulation Very low temperature coefficient Use as Regulator or Reference Needs minimum capacitance for stability Current and Thermal Limiting Stable with low-ESR output capacitors (10mΩ to 6Ω) Block Diagram and Typical Applications SM72238 30141325 © 2011 National Semiconductor Corporation 301413 www.national.com SM72238 SolarMagic Micropower Voltage Regulators May 9, 2011 SM72238 Connection Diagrams TO-252 (D-Pak) 30141370 Front View Ordering Information Package Temperature Range VOUT Part Number TO-252 (DPAK) -40<TJ<125 3.0 SM72238TDE-3.0 TO-252 (DPAK) -40<TJ<125 TO-252 (DPAK) -40<TJ<125 www.national.com Package Marking Transport Media S72238–3.0 250 Units in Tape and Reel SM72238TD-3.0 75 Units in Rail SM72238TDX-3.0 75 Units in Rail S72238–3.3 SM72238TDE-3.3 SM72238TDX-3.3 250 Units in Tape and Reel TD03B 2500 Units in Tape and Reel SM72238TD-5.0 5.0 TD03B 2500 Units in Tape and Reel SM72238TD-3.3 3.3 NSC Drawing 75 Units in Rail SM72238TDE-5.0 S72238 SM72238TDX-5.0 250 Units in Tape and Reel 2500 Units in Tape and Reel 2 TD03B If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Supply Voltage Power Dissipation Junction Temperature (TJ) Ambient Storage Temperature Soldering Dwell Time, Temperature Wave Infrared Vapor Phase ESD Rating Human Body Model(Note 11) Maximum Input Supply Voltage Junction Temperature Range (TJ) (Note 6) 30V −40° to +125°C −0.3 to +30V Internally Limited +150°C −65° to +150°C 4 seconds, 260°C 10 seconds, 240°C 75 seconds, 219°C Electrical Characteristics Parameter (Note 1) 2500V (Note 2) Conditions (Note 2) Tested Limit (Note 3) Typ Design Limit (Note 4) Units 3V Versions Output Voltage TJ = 25°C −25°C ≤ TJ ≤ 85°C Output Voltage 3.0 3.030 V max 2.970 V min 3.0 3.045 V max 2.955 V min Full Operating Temperature Range 3.0 3.060 2.940 V max V min 100μA ≤ IL ≤ 100mA 3.0 3.072 V max 2.928 V min TJ ≤ TJMAX 3.3V Versions Output Voltage TJ = 25°C −25°C ≤ TJ ≤ 85°C Output Voltage 3.3 3.333 V max 3.267 V min 3.3 3.350 V max 3.251 V min Full Operating Temperature Range 3.3 3.366 3.234 V max V min 100μA ≤ IL ≤ 100mA 3.3 3.379 V max 3.221 V min TJ ≤ TJMAX 5.0V Versions Output Voltage TJ = 25°C −25°C ≤ TJ ≤ 85°C Output Voltage 5.0 5.05 V max 4.95 V min 5.0 5.075 V max 4.925 V min Full Operating Temperature Range 5.0 5.1 4.9 V max V min 100μA ≤ IL ≤ 100mA 5.0 5.12 V max 4.88 V min 150 ppm/°C 0.4 % max % max 0.3 % max % max TJ ≤ TJMAX All Voltage Options Output Voltage (Note 7) Temperature Coefficient 50 Line Regulation (Note 9) (VONOM + 1)V ≤ Vin ≤ 30V (Note 10) 0.04 Load Regulation (Note 9) 100μA ≤ IL ≤ 100mA 0.1 3 0.2 0.2 www.national.com SM72238 Operating Ratings Absolute Maximum Ratings (Note 1) SM72238 Parameter Conditions (Note 2) Dropout Voltage (Note 5) IL = 100μA Tested Limit (Note 3) Typ 80 50 IL = 100mA IL = 100μA 75 mV max mV max 600 mV max mV max μA max 120 Current 140 IL = 100mA 8 12 μA max mA max 14 110 Units 150 450 380 Ground Design Limit (Note 4) mA max μA max Dropout Vin = (VONOM − 0.5)V 170 Ground Current IL = 100μA Current Limit Vout = 0 160 200 Thermal Regulation (Note 8) 0.05 0.2 Output Noise, CL = 1μF (5V Only) 430 μV rms 10 Hz to 100 kHz CL = 200μF 160 μV rms 100 μV rms 200 μA max mA max 220 mA max %/W max CL = 3.3μF (Bypass = 0.01μF) Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables. Note 2: Unless otherwise specified all limits guaranteed for VIN = (VONOM + 1)V, IL = 100μA and CL = 1μF. Limits appearing in boldface type apply over the entire junction temperature range for operation. Limits appearing in normal type apply for TA = TJ = 25°C. Note 3: Guaranteed and 100% production tested. Note 4: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing AQL levels. 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: Junction-to-case thermal resistance for the TO-252 package is 5.4°C/W. Note 7: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 8: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a 50mA load pulse at VIN = 30V (1.25W pulse) for T = 10ms. Note 9: 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 10: For IL = 100μA 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 11: Human Body Model 1.5kΩ in series with 100pF. www.national.com 4 SM72238 Typical Performance Characteristics Quiescent Current Dropout Characteristics 30141328 30141327 Input Current Input Current 30141329 30141330 Output Voltage vs. Temperature of 3 Representative Units Quiescent Current 30141332 30141331 5 www.national.com SM72238 Quiescent Current Quiescent Current 30141333 30141334 Quiescent Current Short Circuit Current 30141335 30141336 Dropout Voltage Line Transient Response 30141337 www.national.com 30141344 6 SM72238 Load Transient Response Load Transient Response 30141345 30141346 Output Impedance Ripple Rejection 30141348 30141349 Ripple Rejection Ripple Rejection 30141350 30141351 7 www.national.com SM72238 Shutdown Threshold Voltage Line Regulation 30141354 30141355 Maximum Rated Output Current Thermal Response 30141357 30141358 Output Capacitor ESR Range 30141363 www.national.com 8 EXTERNAL CAPACITORS A 1.0μF (or greater) capacitor is required between the output and ground for stability. Without this capacitor the part will oscillate. Most types of tantalum or aluminum electrolytics work fine here; even film types work but are not recommended for reasons of cost. Many aluminum electrolytics have electrolytes that freeze at about −30°C, so solid tantalums are recommended for operation below −25°C. The important parameters of the capacitor are an ESR of about 5Ω or less and a resonant frequency above 500kHz. The value of this capacitor may be increased without limit. Ceramic capacitors whose value is greater than 1000pF should not be connected directly from the SM72238 output to ground. Ceramic capacitors typically have ESR values in the range of 5 to 10mΩ, a value below the lower limit for stable operation (see curve Output Capacitor ESR Range). The reason for the lower ESR limit is that the loop compensation of the part relies on the ESR of the output capacitor to provide the zero that gives added phase lead. The ESR of ceramic capacitors is so low that this phase lead does not occur, significantly reducing phase margin. A ceramic output REDUCING OUTPUT NOISE In reference applications it may be advantageous to reduce the AC noise present at the output. One method is to reduce the regulator bandwidth by increasing the size of the output capacitor. This is the only way noise can be reduced but is relatively inefficient, as increasing the capacitor from 1μF to 220μF only decreases the noise from 430μV to 160μV rms for a 100kHz bandwidth at 5V output. Typical Applications 5 Volt Current Limiter 30141310 *Minimum input-output voltage ranges from 40mV to 400mV, depending on load current. Current limit is typically 160mA. 9 www.national.com SM72238 capacitor can be used if a series resistance is added (recommended value of resistance about 0.1Ω to 2Ω). At lower values of output current, less output capacitance is required for stability. The capacitor can be reduced to 0.33μF for currents below 10mA or 0.1μF for currents below 1mA. Unlike many other regulators, the SM72238 will remain stable and in regulation with no load in addition to the internal voltage divider. This is especially important in CMOS RAM keep-alive applications. A 1μF tantalum, ceramic or aluminum electrolytic capacitor should be placed from the SM72238 input to ground 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. Application Hints 30141323 SM72238 Schematic Diagram www.national.com 10 SM72238 Physical Dimensions inches (millimeters) unless otherwise noted D-Pak Package NS Package Number TD03B 11 www.national.com SM72238 SolarMagic Micropower Voltage Regulators Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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