LM4030 SOT-23 Ultra-High Precision Shunt Voltage Reference General Description Features The LM4030 is an ultra-high precision shunt voltage reference, having exceptionally high initial accuracy (0.05%) and temperature stability (10ppm/°C). The LM4030 is available with fixed voltage options of 2.5V and 4.096V. Despite the tiny SOT23 package, the LM4030 exhibits excellent thermal hysteresis (75ppm) and long-term stability (40ppm) as well as immunity to board stress effects. The LM4030 is designed to operate without an external capacitor, but any capacitor up to 10µF may be used. The LM4030 can be powered off as little as 120µA (max) but is capable of shunting up to 30mA continuously. As with any shunt reference, the LM4030 can be powered off of virtually any supply and is a simple way to generate a highly accurate system reference. The LM4030 is available in three grades (A, B, and C). The best grade devices (A) have an initial accuracy of 0.05% with guaranteed temperature coefficient of 10 ppm/°C or less, while the lowest grade parts (C) have an initial accuracy of 0.15% and a temperature coefficient of 30 ppm/°C. ■ ■ ■ ■ ■ ■ ■ ■ ■ High output voltage accuracy 0.05% Low temperature coefficient 10 ppm/°C Extended temperature operation -40-125°C Excellent thermal hysteresis, 75ppm Excellent long-term stability, 40ppm High immunity to board stress effects Capable of handling 50 mA transients Voltage options 2.5V, 4.096V SOT23-5 Package Applications ■ ■ ■ ■ ■ ■ Data Acquisition/Signal path Test and Measurement Automotive & Industrial Communications Instrumentation Power Management Typical Application Circuit 30046301 Connection Diagram Top View 30046302 SOT23-5 Package NS Package Number MF05A © 2008 National Semiconductor Corporation 300463 www.national.com LM4030 SOT-23 Ultra-High Precision Shunt Voltage Reference May 30, 2008 LM4030 Ordering Information Input Output Voltage Accuracy at 25°C And Temperature Coefficient LM4030 Supplied as 1000 units, Tape and Reel 0.05%, 10 ppm/°C max (A grade) LM4030AMF-2.5 LM4030AMFX-2.5 R5JA LM4030AMF-4.096 LM4030AMFX4.096 R5KA LM4030BMF-2.5 LM4030BMFX-2.5 R5JB LM4030BMF-4.096 LM4030BMFX4.096 R5KB LM4030CMF-2.5 LM4030CMFX-2.5 R5JC LM4030CMF-4.096 LM4030CMFX4.096 R5KC 0.10%, 20 ppm/°C max (B grade) 0.15%, 30 ppm/°C max (C grade) LM4030 Supplied as 3000 units, Part Marking Tape and Reel Pin Descriptions Pin # www.national.com Name Function 1 N/C No connect pin, leave floating 2 GND, N/C Ground or no connect 3 N/C No connect pin, leave floating 4 VREF Reference voltsge 5 GND Ground 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Maximum Voltage on any input Power Dissipation (TA = 25°C) (Note 2) Storage Temperature Range 2kV Operating Ratings -0.3 to 6V Maximum Continuous Shunt Current Maximum Shunt Current (<1s) Junction Temperature Range (TJ) 350mW −65°C to 150°C Lead Temperature (soldering, 10sec) Vapor Phase (60 sec) 220°C 30mA 50mA −40°C to +125°C 260°C 215°C Electrical Characteristics LM4030-2.5 (VOUT = 2.5V) Limits in standard type are for TJ = 25°C only, and limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Symbol VREF Parameter Reverse Breakdown Voltage Conditions Min Typ Max (Note 4) (Note 5) (Note 4) Unit 2.5 V ISHUNT = 120µA Reverse Breakdown Voltage Tolerance (ISHUNT = 120µA) IRMIN TC LM4030A-2.5 (A Grade - 0.05%) -0.05 0.05 % LM4030B-2.5 (B Grade - 0.10%) -0.10 0.10 % LM4030C-2.5 (C Grade - 0.15%) -0.15 0.15 % 120 µA 0°C ≤ TJ ≤ + 85°C 10 ppm / °C -40°C ≤ TJ ≤ +125°C 20 ppm / °C LM4030B-2.5 -40°C ≤ TJ ≤ +125°C 20 ppm / °C LM4030C-2.5 -40°C ≤ TJ ≤ +125°C 30 ppm / °C 110 ppm / mA Minimum Operating Current Temperature Coefficient (Note 6) LM4030A-2.5 Reverse Breakdown Voltage Change 160µA ≤ ISHUNT ≤ 30mA with Current 25 ΔVREF Long Term Stability (Note 7) 1000 Hrs, TA = 30°C 40 ppm VHYST Thermal Hysteresis (Note 8) -40°C ≤ TJ ≤ +125°C 75 ppm Output Noise Voltage (Note 9) 0.1 Hz to 10 Hz 105 µVPP ΔVREF/ΔISHUNT VN 3 www.national.com LM4030 Infrared (15sec) ESD Susceptibility (Note 3) Human Body Model Absolute Maximum Ratings (Note 1) LM4030 Electrical Characteristics LM4030-4.096 (VOUT = 4.096V) Limits in standard type are for TJ = 25°C only, and limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Symbol VREF Parameter Reverse Breakdown Voltage Conditions Min (Note 4) ISHUNT = 130µA Typ (Note 5) Max (Note 4) Unit 4.096 V Reverse Breakdown Voltage Tolerance ( ISHUNT = 130µA) IRMIN TC LM4030A-4.096 (A Grade - 0.05%) -0.05 0.05 % LM4030B-4.096 (B Grade - 0.10%) -0.10 0.10 % LM4030C-4.096 (C Grade - 0.15%) -0.15 0.15 % 130 µA 0°C ≤ TJ ≤ + 85°C 10 ppm / °C ppm / °C ppm / °C Minimum Operating Current Temperature Coefficient (Note 6) LM4030A-4.096 -40°C ≤ TJ ≤ +125°C 20 LM4030B-4.096 -40°C ≤ TJ ≤ +125°C 20 LM4030C-4.096 -40°C ≤ TJ ≤ +125°C 30 ppm / °C ΔVREF/ΔILOAD Reverse Breakdown Voltage Change with Current 160µA ≤ ISHUNT ≤ 30mA 15 95 ppm / mA ΔVREF Long Term Stability (Note 7) 1000 Hrs, TA = 30°C 40 ppm VHYST Thermal Hysteresis (Note 8) -40°C ≤ TJ ≤ +125°C 75 ppm Output Noise Voltage (Note 9) 0.1 Hz to 10 Hz 165 µVPP VN Note 1: Absolute Maximum Ratings indicate limits beyond which damage may occur to the device. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications, see Electrical Characteristics. Note 2: Without PCB copper enhancements. The maximum power dissipation must be de-rated at elevated temperatures and is limited by TJMAX (maximum junction temperature), θJ-A (junction to ambient thermal resistance) and TA (ambient temperature). The maximum power dissipation at any temperature is: PDissMAX = (TJMAX - TA) /θJ-A up to the value listed in the Absolute Maximum Ratings. θJ-A for SOT23-5 package is 220°C/W, TJMAX = 125°C. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. Note 4: Limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control. Note 5: Typical numbers are at 25°C and represent the most likely parametric norm. Note 6: Temperature coefficient is measured by the "Box" method; i.e., the maximum ΔVREF is divided by the maximum ΔT. Note 7: Long term stability is VREF @25°C measured during 1000 hrs. This measurement is taken for IR = 500 µA. Note 8: Thermal hysteresis is defined as the change in +25°C output voltage before and after cycling the device from (-40°C to 125°C) eight times. Note 9: Low frequency peak-to-peak noise measured using first-order 0.1 Hz HPF and second-order 10 Hz LPF. www.national.com 4 LM4030 Typical Performance Characteristics for 2.5V Output Voltage vs Temperature 0.1 - 10 Hz Peak-to-Peak Noise 30046303 30046332 Start Up - 120 µA Start Up - 50 mA 30046305 30046304 Reverse Breakdown Voltage Change with Current Reverse Dynamic Impedance vs Frequency 30046314 30046340 5 www.national.com LM4030 Typical Performance Characteristics for 4.096V Output Voltage vs Temperature 0.1 - 10 Hz Peak-to-Peak Noise 30046306 30046349 Start Up - 130 µA Start Up - 50 mA 30046308 30046307 Reverse Breakdown Voltage Change with Current Reverse Dynamic Impedance vs Frequency 30046312 www.national.com 30046341 6 LM4030 Typical Performance Characteristics Forward Characteristic Load Transient Response 30046313 30046311 Minimum Operating Current Noise Spectrum 30046316 30046317 Thermal Hysteresis Distribution Output Voltage vs Thermal Cycle (-40°C to 125°C) 30046351 30046330 7 www.national.com LM4030 Long Term Stability (TA = 25°C) Long Term Stability (TA =125°C) 30046347 www.national.com 30046348 8 THEORY OF OPERATION The LM4030 is an ultra-high precision shunt voltage reference, having exceptionally high initial accuracy (0.05%) and temperature stability (10ppm/°C). The LM4030 is available with fixed voltage options of 2.5V and 4.096V. Despite the tiny SOT23 package, the LM4030 exhibits excellent thermal hysteresis (75ppm) and long-term stability (25ppm). The LM4030 is designed to operate without an external capacitor, but any capacitor up to 10 µF may be used. The LM4030 can be powered off as little as 120 µA (max) but is capable of shunting up to 30 mA continuously. The typical application circuit for the LM4030 is shown in Figure 1. 30046345 FIGURE 3. Reverse Dynamic Impedance vs COUT 30046301 As with other regulators, an external capacitor reduces the amplitude of the VREF transient when a sudden change in loading takes place. The capacitor should be placed as close to the part as possible to reduce the effects of unwanted board parasitics. FIGURE 1. Typical Application Circuit COMPONENT SELECTION A resistor must be chosen to set the maximum operating current for the LM4030 (RZ in Figure 1). The value of the resistor can be calculated using the following equation: THERMAL HYSTERESIS Thermal hysteresis is the defined as the change in output voltage at 25°C after some deviation from 25°C. This is to say that thermal hysteresis is the difference in output voltage between two points in a given temperature profile. An illustrative temperature profile is shown in Figure 4. RZ = (VIN - VREF)/(IMIN_OPERATING + ILOAD_MAX) RZ is chosen such that the total current flowing through RZ is greater than the maximum load current plus the minimum operating current of the reference itself. This ensures that the reference is never starved for current. Running the LM4030 at higher currents is advantageous for reducing noise. The reverse dynamic impedance of the VREF node scales inversely with the shunted current (see Figure 2) leading to higher rejection of noise emanating from the input supply and from EMI (electro-magnetic interferrence). 30046318 FIGURE 4. Illustrative Temperature Profile This may be expressed analytically as the following: Where VHYS = Thermal hysteresis expressed in ppm VREF = Nominal preset output voltage VREF1 = VREF before temperature fluctuation 30046346 FIGURE 2. Reverse Dynamic Impedance vs IOUT 9 www.national.com LM4030 The LM4030 is designed to operate with or without a bypass capacitor (COUT in Figure 1) and is stable with capacitors of up to 10 μF. The use of a bypass capacitor can improve transient response and reduce broadband noise. Additionally, a bypass capacitor will counter the rising reverse dynamic impedance at higher frequencies improving noise immunity (see Figure 3). Application Information LM4030 shifts in VREF arise due to offsets between matched devices within the regulation loop. Both passive and active devices naturally experience drift over time and stress and temperature gradients across the silicon die also generate offset. The LM4030 incorporates a dynamic offset cancellation scheme which compensates for offsets developing within the regulation loop. This gives the LM4030 excellent long-term stability (40 ppm typical) and thermal hysteresis performance (75ppm typical), as well as substantial immunity to PCB stress effects, despite being packaged in a tiny SOT23. VREF2 = VREF after temperature fluctuation. The LM4030 features a low thermal hysteresis of 75 ppm (typical) from -40°C to 125°C after 8 temperature cycles. TEMPERATURE COEFFICIENT Temperature drift is defined as the maximum deviation in output voltage over the temperature range. This deviation over temperature may be illustrated as shown in Figure 5. EXPRESSION OF ELECTRICAL CHARACTERISTICS Electrical characteristics are typically expressed in mV, ppm, or a percentage of the nominal value. Depending on the application, one expression may be more useful than the other. To convert one quantity to the other one may apply the following: ppm to mV error in output voltage: 30046320 FIGURE 5. Illustrative VREF vs Temperature Profile Where: VREF is in volts (V) and VERROR is in milli-volts (mV). Bit error (1 bit) to voltage error (mV): Temperature coefficient may be expressed analytically as the following: VREF is in volts (V), VERROR is in milli-volts (mV), and n is the number of bits. mV to ppm error in output voltage: TD = Temperature drift VREF = Nominal preset output voltage VREF_MIN = Minimum output voltage over operating temperature range VREF_MAX = Maximum output voltage over operating temperature range ΔT = Operating temperature range. The LM4030 features a low temperature drift of 10ppm (max) to 30ppm (max), depending on the grade. Where: VREF is in volts (V) and VERROR is in milli-volts (mV). Voltage error (mV) to percentage error (percent): DYNAMIC OFFSET CANCELLATION AND LONG TERM STABILITY Aside from initial accuracy and drift performance, other specifications such as thermal hysteresis and long-term stability can affect the accuracy of a voltage reference, especially over the lifetime of the application. The reference voltage can also shift due to board stress once the part is mounted onto the PCB and during subsequent thermal cycles. Generally, these www.national.com Where: VREF is in volts (V) and VERROR is in milli-volts (mV). 10 11 www.national.com LM4030 voltage drop proportional to load current and should be minimized. The LM4030 should be placed as close to the load it is driving as the layout will allow. The location of RZ is not important, but COUT should be as close to the LM4030 as possible so added ESR does not degrade the transient performance. PRINTED CIRCUIT BOARD and LAYOUT CONSIDERATIONS The LM4030 has a very small change in reverse voltage with current (25ppm/mA typical) so large variations in load current (up to 50mA) should not appreciably shift VREF. Parasitic resistance between the LM4030 and the load introduces a LM4030 Physical Dimensions inches (millimeters) unless otherwise noted SOT23-5 Package NS Package Number MF05A www.national.com 12 LM4030 Notes 13 www.national.com LM4030 SOT-23 Ultra-High Precision Shunt Voltage Reference Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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