LM4050 Precision Micropower Shunt Voltage Reference General Description Ideal for space critical applications, the LM4050 precision voltage reference is available in the sub-miniature (3 mm x 1.3 mm) SOT-23 surface-mount package. The LM4050’s design eliminates the need for an external stabilizing capacitor while ensuring stability with any capacitive load, thus making the LM4050 easy to use. Further reducing design effort is the availability of several fixed reverse breakdown voltages: 2.048V, 2.500V, 4.096V, 5.000V, 8.192V, and 10.000V. The minimum operating current increases from 60 µA for the LM4050-2.0 to 100 µA for the LM4050-10.0. All versions have a maximum operating current of 15 mA. The LM4050 utilizes fuse and zener-zap reverse breakdown voltage trim during wafer sort to ensure that the prime parts have an accuracy of better than ± 0.1% (A grade) at 25˚C. Bandgap reference temperature drift curvature correction and low dynamic impedance ensure stable reverse breakdown voltage accuracy over a wide range of operating temperatures and currents. All grades and voltage options of the LM4050 are available in both an industrial temperature range (−40˚C and +85˚C) and an extended temperature range (−40˚C and +125˚C). Features n Small packages: SOT-23 n No output capacitor required n Tolerates capacitive loads n Fixed reverse breakdown voltages of 2.048V, 2.500V, 4.096V, 5.000V, 8.192V, and 10.000V Key Specifications (LM4050-2.5) j Output voltage tolerance (A grade, 25˚C) ± 0.1% (max) j Low output noise (10 Hz to 10 kHz) 41 µVrms(typ) j Wide operating current range 60 µA to 15 mA j Industrial temperature range −40˚C to +85˚C j Extended temperature range −40˚C to +125˚C j Low temperature coefficient 50 ppm/˚C (max) Applications n n n n n n n n Portable, Battery-Powered Equipment Data Acquisition Systems Instrumentation Process Control Energy Management Product Testing Automotive Precision Audio Components Connection Diagram SOT-23 10104501 *This pin must be left floating or connected to pin 2. Top View See NS Package Number MF03A © 2004 National Semiconductor Corporation DS101045 www.national.com LM4050 Precision Micropower Shunt Voltage Reference July 2004 LM4050 Ordering Information Industrial Temperature Range (−40˚C to +85˚C) Reverse Breakdown Voltage Tolerance at 25˚C and Average Reverse Breakdown Voltage Temperature Coefficient ± 0.1%, 50 ppm/˚C max (A grade) ± 0.2%, 50 ppm/˚C max (B grade) ± 0.5%, 50 ppm/˚C max (C grade) LM4050 Supplied as 1000 Units, Tape and Reel LM4050 Supplied as 3000 Units, Tape and Reel LM4050AIM3-2.0 LM4050AIM3X-2.0 LM4050AIM3-2.5 LM4050AIM3X-2.5 LM4050AIM3-4.1 LM4050AIM3X-4.1 LM4050AIM3-5.0 LM4050AIM3X-5.0 LM4050AIM3-8.2 LM4050AIM3X-8.2 LM4050AIM3-10 LM4050AIM3X-10 LM4050BIM3-2.0 LM4050BIM3X-2.0 LM4050BIM3-2.5 LM4050BIM3X-2.5 LM4050BIM3-4.1 LM4050BIM3X-4.1 LM4050BIM3-5.0 LM4050BIM3X-5.0 LM4050BIM3-8.2 LM4050BIM3X-8.2 LM4050BIM3-10 LM4050BIM3X-10 LM4050CIM3-2.0 LM4050CIM3X-2.0 LM4050CIM3-2.5 LM4050CIM3X-2.5 LM4050CIM3-4.1 LM4050CIM3X-4.1 LM4050CIM3-5.0 LM4050CIM3X-5.0 LM4050CIM3-8.2 LM4050CIM3X-8.2 LM4050CIM3-10 LM4050CIM3X-10 Extended Temperature Range (−40˚C to +125˚C) Reverse Breakdown Voltage Tolerance at 25˚C and Average Reverse Breakdown Voltage Temperature Coefficient ± 0.1%, 50 ppm/˚C max (A grade) ± 0.2%, 50 ppm/˚C max (B grade) ± 0.5%, 50 ppm/˚C max (C grade) www.national.com LM4050 Supplied as 1000 Units, Tape and Reel LM4050 Supplied as 3000 Units, Tape and Reel LM4050AEM3-2.0 LM4050AEM3X-2.0 LM4050AEM3-2.5 LM4050AEM3X-2.5 LM4050AEM3-4.1 LM4050AEM3X-4.1 LM4050AEM3-5.0 LM4050AEM3X-5.0 LM4050AEM3-8.2 LM4050AEM3X-8.2 LM4050AEM3-10 LM4050AEM3X-10 LM4050BEM3-2.0 LM4050BEM3X-2.0 LM4050BEM3-2.5 LM4050BEM3X-2.5 LM4050BEM3-4.1 LM4050BEM3X-4.1 LM4050BEM3-5.0 LM4050BEM3X-5.0 LM4050BEM3-8.2 LM4050BEM3X-8.2 LM4050BEM3-10 LM4050BEM3X-10 LM4050CEM3-2.0 LM4050CEM3X-2.0 LM4050CEM3-2.5 LM4050CEM3X-2.5 LM4050CEM3-4.1 LM4050CEM3X-4.1 LM4050CEM3-5.0 LM4050CEM3X-5.0 LM4050CEM3-8.2 LM4050CEM3X-8.2 LM4050CEM3-10 LM4050CEM3X-10 2 Only three fields of marking are possible on the SOT-23’s small surface. This table gives the meaning of the three fields. Part Marking RCA RDA REA Field Definition First Field: R = Reference Second Field: RFA N = 2.048V Voltage Option RGA C = 2.500V Voltage Option RNA D = 4.096V Voltage Option RCB E = 5.000V Voltage Option RDB F = 8.192V Voltage Option REB G = 10.000V Voltage Option RFB RGB Third Field: RNB RCC A–C = Initial Reverse Breakdown Voltage or Reference Voltage Tolerance RDC A = ± 0.1%, B = ± 0.2%, C = +0.5%, REC RFC RGC RNC 3 www.national.com LM4050 SOT-23 Package Marking Information LM4050 Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Current 20 mA Forward Current 10 mA Power Dissipation (TA = 25˚C) (Note 2) Industrial Temperature Range −40˚C ≤ TA ≤ +85˚C Extended temperature Range −40˚C ≤ TA ≤ +125˚C Reverse Current M3 Package Storage Temperature (Tmin ≤ TA ≤ Tmax) Temperature Range 280 mW LM4050-2.0 60 µA to 15 mA −65˚C to +150˚C LM4050-2.5 60 µA to 15 mA LM4050-4.1 68 µA to 15 mA LM4050-5.0 74 µA to 15 mA Lead Temperature M3 Package Vapor phase (60 seconds) +215˚C LM4050-8.2 91 µA to 15 mA Infrared (15 seconds) +220˚C LM4050-10.0 100 µA to 15 mA ESD Susceptibility Human Body Model (Note 3) 2 kV Machine Model (Note 3) 200V See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. LM4050-2.0 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1%, ± 0.2%, and 0.5% respectively. Symbol VR IRMIN ∆VR/∆T ∆VR/∆IR Parameter Conditions Typical (Note 4) LM4050AIM3 LM4050AEM3 Limits (Note 5) LM4050BIM3 LM4050BEM3 Limits (Note 5) LM4050CIM3 LM4050CEM3 Limits (Note 5) Units (Limit) Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 100 µA 2.048 ± 2.048 ± 4.096 ± 10.24 mV (max) Industrial Temp. Range ± 9.0112 ± 11.4688 ± 14.7456 mV (max) Extended Temp. Range ± 12.288 ± 14.7456 ± 17.2032 mV (max) 60 60 60 µA (max) 65 65 65 µA (max) Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) V 41 IR = 10 mA ± 20 IR = 1 mA ± 15 IR = 100 µA ± 15 IRMIN ≤ IR ≤ 1 mA 0.3 1 mA ≤ IR ≤ 15 mA µA ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 0.8 0.8 0.8 mV (max) 1.2 1.2 1.2 mV (max) 6.0 6.0 6.0 mV (max) 8.0 8.0 8.0 mV (max) mV 2.3 mV ZR Reverse Dynamic Impedance IR = 1 mA, f = 120 Hz, IAC = 0.1 IR 0.3 Ω eN Wideband Noise IR = 100 µA 34 µVrms ppm 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA 120 VHYST Thermal Hysteresis (Note 8) ∆T = −40˚C to 125˚C 0.7 www.national.com 4 mV LM4050 LM4050-2.5 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1%, ± 0.2%, and 0.5% respectively. Symbol VR IRMIN ∆VR/∆T ∆VR/∆IR Parameter Typical (Note 4) Conditions LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) 2.500 Units (Limit) Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 100 µA ± 2.5 ± 5.0 ± 13 mV (max) Industrial Temp. Range ± 11 ± 14 ± 21 mV (max) Extended Temp. Range ± 15 ± 18 ± 25 mV (max) 60 60 60 µA (max) 65 65 65 µA (max) Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) V 41 IR = 10 mA ± 20 IR = 1 mA ± 15 IR = 100 µA ± 15 IRMIN ≤ IR ≤ 1 mA 0.3 1 mA ≤ IR ≤ 15 mA µA ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 0.8 0.8 0.8 mV (max) 1.2 1.2 1.2 mV (max) 6.0 6.0 6.0 mV (max) 8.0 8.0 8.0 mV (max) mV 2.3 mV ZR Reverse Dynamic Impedance IR = 1 mA, f = 120 Hz, IAC = 0.1 IR 0.3 Ω eN Wideband Noise IR = 100 µA 41 µVrms 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA 120 ppm VHYST Thermal Hysteresis (Note 8) ∆T = −40˚C to 125˚C 0.7 mV LM4050-4.1 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1%, ± 0.2%, and 0.5% respectively. Symbol VR IRMIN ∆VR/∆T ∆VR/∆IR Parameter Typical (Note 4) Conditions LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) 4.096 Units (Limit) Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 100 µA ± 4.1 ± 8.2 ± 21 mV (max) Industrial Temp. Range ± 18 ± 22 ± 34 mV (max) Extended Temp. Range ± 25 ± 29 ± 41 mV (max) 68 68 68 µA (max) Industrial Temp. Range 73 73 73 µA (max) Extended Temp. Range 78 78 78 µA (max) Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) V 52 IR = 10 mA ± 30 IR = 1 mA ± 20 IR = 100 µA ± 20 IRMIN ≤ IR ≤ 1 mA 0.2 1 mA ≤ IR ≤ 15 mA µA ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 0.9 0.9 0.9 mV (max) 1.2 1.2 1.2 mV (max) 7.0 7.0 7.0 mV (max) 10.0 10.0 10.0 mV (max) mV 2.0 5 mV www.national.com LM4050 LM4050-4.1 Electrical Characteristics (Continued) Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1%, ± 0.2%, and 0.5% respectively. Symbol ZR Parameter Reverse Dynamic Impedance Typical (Note 4) Conditions IR = 1 mA, f = 120 Hz, LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) Units (Limit) 0.5 Ω 93 µVrms 120 ppm 1.148 mV IAC = 0.1 IR eN Wideband Noise IR = 100 µA 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA VHYST Thermal Hysteresis (Note 8) ∆T = −40˚C to 125˚C LM4050-5.0 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1%, ± 0.2% and 0.5% respectively. Symbol VR IRMIN ∆VR/∆T ∆VR/∆IR Parameter Typical (Note 4) Conditions 5.000 IR = 100 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 100 µA ± 5.0 ± 10 ± 25 mV (max) Industrial Temp. Range ± 22 ± 27 ± 42 mV (max) Extended Temp. Range ± 30 ± 35 ± 50 mV (max) 74 74 74 µA (max) Industrial Temp. Range 80 80 80 µA (max) Extended Temp. Range 90 90 90 µA (max) Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) Reverse Dynamic Impedance Wideband Noise V 56 IR = 10 mA ± 30 IR = 1 mA ± 20 IR = 100 µA ± 20 IRMIN ≤ IR ≤ 1 mA 0.2 µA ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 1.0 1.0 1.0 mV (max) 1.4 1.4 1.4 mV (max) 8.0 8.0 8.0 mV (max) 12.0 12.0 12.0 mV (max) mV 2.0 IR = 1 mA, f = 120 Hz, 0.5 mV Ω Ω (max) IAC = 0.1 IR eN Units (Limit) Reverse Breakdown Voltage 1 mA ≤ IR ≤ 15 mA ZR LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) IR = 100 µA 93 µVrms 120 ppm 1.4 mV 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA VHYST Thermal Hysteresis (Note 8) www.national.com ∆T = −40˚C to 125˚C 6 LM4050 LM4050-8.2 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1% and ± 0.2% and 0.5% respectively. Symbol VR IRMIN ∆VR/∆T ∆VR/∆IR Parameter Typical (Note 4) Conditions 8.192 Units (Limit) Reverse Breakdown Voltage IR = 150 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 150 µA ± 8.2 ± 16 ± 41 mV (max) Industrial Temp. Range ± 35 ± 43 ± 68 mV (max) Extended Temp. Range ± 49 ± 57 ± 82 mV (max) 91 91 91 µA (max) Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) Reverse Dynamic Impedance V 74 µA Industrial Temp. Range 95 95 95 µA (max) Extended Temp. Range 100 100 100 µA (max) IR = 10 mA ± 40 IR = 1 mA ± 20 IR = 150 µA ± 20 IRMIN ≤ IR ≤ 1 mA 0.6 1 mA ≤ IR ≤ 15 mA ZR LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 1.3 1.3 1.3 mV (max) 2.5 2.5 2.5 mV (max) 10.0 10.0 10.0 mV (max) 18.0 18.0 18.0 mV (max) mV 7.0 IR = 1 mA, f = 120 Hz, mV 0.6 Ω 150 µVrms 120 ppm 2.3 mV IAC = 0.1 IR eN Wideband Noise IR = 150 µA 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 150 µA VHYST Thermal Hysteresis (Note 8) ∆T = −40˚C to 125˚C 7 www.national.com LM4050 LM4050-10.0 Electrical Characteristics Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A, B and C designate initial Reverse Breakdown Voltage tolerances of ± 0.1% and ± 0.2% and 0.5% respectively. Symbol VR Parameter Typical (Note 4) Conditions 10.00 ∆VR/∆T ∆VR/∆IR IR = 150 µA Reverse Breakdown Voltage Tolerance (Note 6) IR = 150 µA ± 10 ± 20 Industrial Temp. Range ± 43 ± 53 ± 83 mV (max) Extended Temp. Range ± 60 ± 70 ± 100 mV (max) 100 100 100 µA (max) Industrial Temp. Range 103 103 103 µA (max) Extended Temp. Range 110 110 110 µA (max) Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) Reverse Breakdown Voltage Change with Operating Current Change (Note 7) Reverse Dynamic Impedance V ± 50 80 IR = 10 mA ± 40 IR = 1 mA ± 20 IR = 150 µA ± 20 IRMIN ≤ IR ≤ 1 mA 0.8 1 mA ≤ IR ≤ 15 mA ZR Units (Limit) Reverse Breakdown Voltage Minimum Operating Current IRMIN LM4050AIM3 LM4050BIM3 LM4050CIM3 LM4050AEM3 LM4050BEM3 LM4050CEM3 Limits Limits Limits (Note 5) (Note 5) (Note 5) µA ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 1.5 1.5 1.5 mV (max) 3.5 3.5 3.5 mV (max) 12.0 12.0 12.0 mV (max) 23.0 23.0 23.0 mV (max) mV 8.0 IR = 1 mA, f = 120 Hz, mV (max) mV 0.7 Ω 150 µVrms 120 ppm 2.8 mV IAC = 0.1 IR eN Wideband Noise IR = 150 µA 10 Hz ≤ f ≤ 10 kHz ∆VR Reverse Breakdown Voltage Long Term Stability t = 1000 hrs T = 25˚C ± 0.1˚C IR = 150 µA VHYST Thermal Hysteresis (Note 8) ∆T = −40˚C to 125˚C Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax − TA)/θJA or the number given in the Absolute Maximum Ratings, whichever is lower. For the LM4050, TJmax = 125˚C, and the typical thermal resistance (θJA), when board mounted, is 326˚C/W for the SOT-23 package. Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. Note 4: Typicals are at TJ = 25˚C and represent most likely parametric norm. Note 5: Limits are 100% production tested at 25˚C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate National’s AOQL. Note 6: The boldface (over-temperature) limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown Voltage Tolerance ± [(∆V R/∆T)(max∆T)(VR)]. Where, ∆VR/∆T is the VR temperature coefficient, max∆T is the maximum difference in temperature from the reference point of 25˚C to T MIN or TMAX, and VR is the reverse breakdown voltage. The total over-temperature tolerance for the different grades in the industrial temperature range where max∆T = 65˚C is shown below: A-grade: ± 0.425% = ± 0.1% ± 50 ppm/˚C x 65˚C B-grade: ± 0.525% = ± 0.2% ± 50 ppm/˚C x 65˚C C-grade: ± 0.825% = ± 0.5% ± 50 ppm/˚C x 65˚C Therefore, as an example, the A-grade LM4050-2.5 has an over-temperature Reverse Breakdown Voltage tolerance of ± 2.5V x 0.425% = ± 11 mV. Note 7: Load regulation is measured on pulse basis from no load to the specified load current. Output changes due to die temperature change must be taken into account separately. Note 8: Thermal hysteresis is defined as the difference in voltage measured at +25˚C after cycling to temperature -40˚C and the 25˚C measurement after cycling to temperature +125˚C. www.national.com 8 LM4050 Typical Performance Characteristics Output Impedance vs Frequency Output Impedance vs Frequency 10104510 10104511 Reverse Characteristics and Minimum Operating Current Noise Voltage vs Frequency 10104512 10104513 Thermal Hysteresis 10104529 9 www.national.com LM4050 Start-Up Characteristics LM4050-10.0 RS = 30k 10104505 LM4050-2.5 RS = 30k 10104509 10104507 LM4050-5.0 RS = 30k 10104508 www.national.com 10 LM4050 Functional Block Diagram 10104514 temperature +125˚C and again measured at 25˚C. The resulting VOUT delta shift between the 25˚C measurements is thermal hysteresis. Thermal hysteresis is common in precision references and is induced by thermal-mechanical package stress. Changes in environmental storage temperature, operating temperature and board mounting temperature are all factors that can contribute to thermal hysteresis. In a conventional shunt regulator application (Figure 1) , an external series resistor (RS) is connected between the supply voltage and the LM4050. RS determines the current that flows through the load (IL) and the LM4050 (IQ). Since load current and supply voltage may vary, RS should be small enough to supply at least the maximum guaranteed IRMIN (spec. table) to the LM4050 even when the supply voltage is at its minimum and the load current is at its maximum value. When the supply voltage is at its maximum and IL is at its minimum, RS should be large enough so that the current flowing through the LM4050 is less than 15 mA. RS is determined by the supply voltage, (VS), the load and operating current, (IL and IQ), and the LM4050’s reverse breakdown voltage, VR. Applications Information The LM4050 is a precision micro-power curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4050 is available in the sub-miniature SOT-23 surface-mount package. The LM4050 has been designed for stable operation without the need of an external capacitor connected between the “+” pin and the “−” pin. If, however, a bypass capacitor is used, the LM4050 remains stable. Reducing design effort is the availability of several fixed reverse breakdown voltages: 2.048V, 2.500V, 4.096V, 5.000V, 8.192V, and 10.000V. The minimum operating current increases from 60 µA for the LM4050-2.0 to 100 µA for the LM4050-10.0. All versions have a maximum operating current of 15 mA. LM4050s in the SOT-23 packages have a parasitic Schottky diode between pin 2 (−) and pin 3 (Die attach interface contact). Therefore, pin 3 of the SOT-23 package must be left floating or connected to pin 2. The 4.096V version allows single +5V 12-bit ADCs or DACs to operate with an LSB equal to 1 mV. For 12-bit ADCs or DACs that operate on supplies of 10V or greater, the 8.192V version gives 2 mV per LSB. The typical thermal hysteresis specification is defined as the change in +25˚C voltage measured after thermal cycling. The device is thermal cycled to temperature -40˚C and then measured at 25˚C. Next the device is thermal cycled to Typical Applications 10104515 FIGURE 1. Shunt Regulator 11 www.national.com LM4050 Typical Applications (Continued) 10104516 **Ceramic monolithic *Tantalum FIGURE 2. LM4050-4.1’s Nominal 4.096 breakdown voltage gives ADC12451 1 mV/LSB www.national.com 12 LM4050 Typical Applications (Continued) 10104517 FIGURE 3. Bounded amplifier reduces saturation-induced delays and can prevent succeeding stage damage. Nominal clamping voltage is ± 11.5V (LM4050’s reverse breakdown voltage +2 diode VF). 10104518 FIGURE 4. Protecting Op Amp input. The bounding voltage is ± 4V with the LM4050-2.5 (LM4050’s reverse breakdown voltage + 3 diode VF). 13 www.national.com LM4050 Typical Applications (Continued) 10104519 FIGURE 5. Precision ± 4.096V Reference 10104521 10104522 FIGURE 6. Precision 1 µA to 1 mA Current Sources www.national.com 14 LM4050 Precision Micropower Shunt Voltage Reference Physical Dimensions inches (millimeters) unless otherwise noted Plastic Surface Mount Package (M3) NS Package Number MF03A (JEDEC Registration TO-236AB) LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.