LM4041 LM4041 Precision Micropower Shunt Voltage Reference Literature Number: SNOS641D LM4041 Precision Micropower Shunt Voltage Reference General Description Key Specifications (LM4041-1.2) Ideal for space critical applications, the LM4041 precision voltage reference is available in the sub-miniature SC70 and SOT-23 surface-mount packages. The LM4041’s advanced design eliminates the need for an external stabilizing capacitor while ensuring stability with any capacitive load, thus making the LM4041 easy to use. Further reducing design effort is the availability of a fixed (1.225V) and adjustable reverse breakdown voltage. The minimum operating current is 60 µA for the LM4041-1.2 and the LM4041-ADJ. Both versions have a maximum operating current of 12 mA. The LM4041 utilizes fuse and zener-zap reverse breakdown or reference 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. Features n n n n Small packages: SOT-23, TO-92, and SC70 No output capacitor required Tolerates capacitive loads Reverse breakdown voltage options of 1.225V and adjustable j Output voltage tolerance ± 0.1%(max) (A grade, 25˚C) j Low output noise (10 Hz to 10kHz) 20µVrms j Wide operating current range 60µA to 12mA j Industrial temperature range −40˚C to +85˚C j Extended temperature range −40˚C to +125˚C j Low temperature coefficient 100 ppm/˚C (max) Applications n n n n n n n Portable, Battery-Powered Equipment Data Acquisition Systems Instrumentation Process Control Energy Management Automotive Precision Audio Components Connection Diagrams SOT-23 01139201 01139240 *This pin must be left floating or connected to pin 2. Top View See NS Package Number MF03A (JEDEC Registration TO-236AB) SC-70 01139246 *This pin must be left floating or connected to pin 1. 01139247 Top View See NS Package Number MAA05A © 2005 National Semiconductor Corporation DS011392 www.national.com LM4041 Precision Micropower Shunt Voltage Reference March 2005 LM4041 Connection Diagrams (Continued) TO-92 01139203 01139232 Bottom View See NS Package Number Z03A Ordering Information Reverse Breakdown Voltage Tolerance at 25˚C and Average Reverse Breakdown Voltage Temperature Coefficient Package M3 (SOT-23) Supplied as 1000 Units Tape and Reel Supplied as 3000 Units Tape and Reel M7 (SC70) Supplied as 1000 Units Tape and Reel Z (TO-92) NS Package Number Supplied as 3000 Units Tape and Reel ± 0.1%, 100 ppm/˚C max (A grade) LM4041AIM3-1.2 LM4041AIM3X-1.2 ± 0.2%, 100 ppm/˚C max (B grade) LM4041BIM3-1.2 LM4041BIM3X-1.2 ± 0.5%, 100 ppm/˚C max (C grade) LM4041CEM3-1.2 LM4041CIM3-1.2 LM4041CEM3-ADJ LM4041CIM3-ADJ LM4041CEM3X-1.2 LM4041CIM7-1.2 LM4041CIM7X-1.2 LM4041CIZ-1.2 MF03A, LM4041CIM3X-1.2 LM4041CIM7-ADJ LM4041CIM7X-ADJ LM4041CIZ-ADJ Z03A, LM4041CEM3X-ADJ MAA05A LM4041CIM3X-ADJ ± 1.0%, 150 ppm/˚C max (D grade) LM4041DEM3-1.2 LM4041DIM3-1.2 LM4041DEM3-ADJ LM4041DIM3-ADJ LM4041DEM3X-1.2 LM4041DIM7-1.2 LM4041DIM7X-1.2 LM4041DIZ-1.2 MF03A, LM4041DIM3X-1.2 LM4041DIM7-ADJ LM4041DIM7X-ADJ LM4041DIZ-ADJ Z03A, LM4041DEM3X-ADJ MAA05A LM4041DIM3X-ADJ ± 2.0%, 150 ppm/˚C max (E grade) LM4041EEM3-1.2 LM4041EIM3-1.2 LM4041EEM3X-1.2 LM4041EIM7-1.2 LM4041EIM3X-1.2 www.national.com LM4041BIM7-1.2 2 LM4041BIM7X-1.2 LM4041EIM7X-1.2 LM4041AIZ-1.2 MF03A, Z03A LM4041BIZ-1.2 MF03A, Z03A, MAA05A LM4041EIZ-1.2 MF03A, Z03A, MAA05A Part Marking R1A (SOT-23 Only) R1B R1C Field Definition First Field: R = Reference Second Field: R1D 1 = 1.225V Voltage Option R1E A = Adjustable Third Field: RAC RAD A–E = Initial Reverse Breakdown Voltage or Reference Voltage Tolerance A = ± 0.1%, B = ± 0.2%, C = ± 0.5%, D = ± 1.0%, E = ± 2.0% 3 www.national.com LM4041 SOT-23 and SC70 Package Marking Information Only three fields of marking are possible on the SOT-23’s and SC70’s small surface. This table gives the meaning of the three fields. LM4041 Absolute Maximum Ratings (Note 1) Soldering (10 seconds) ESD Susceptibility 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 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. Maximum Output Voltage (LM4041-ADJ) +260˚C 15V Operating Ratings(Notes 1, 2) Power Dissipation (TA = 25˚C) (Note 2) M3 Package 306 mW Z Package 550 mW M7 Package 241mW Storage Temperature −65˚C to +150˚C M3 Packages +215˚C Infrared (15 seconds) +220˚C Industrial Temperature Range −40˚C ≤ TA ≤ +85˚C Extended Temperature Range −40˚C ≤ TA ≤ +125˚C Reverse Current Lead Temperature Vapor phase (60 seconds) (Tmin ≤ TA ≤ Tmax) Temperature Range LM4041-1.2 60 µA to 12 mA LM4041-ADJ 60 µA to 12 mA Output Voltage Range LM4041-ADJ Z Package 1.24V to 10V LM4041-1.2 Electrical Characteristics (Industrial Temperature Range) Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C. The grades A and B designate initial Reverse Breakdown Voltage tolerances of ± 0.1% and ± 0.2%, respectively. Symbol VR Parameter Conditions Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage IR = 100 µA Typical (Note 4) 1.225 Tolerance (Note 6) IRMIN ∆VR/∆T Minimum Operating Current Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) ∆VR/∆IR Reverse Breakdown Voltage Change with Operating Current Change (Note 9) ZR Reverse Dynamic Impedance IR = 100 µA ± 20 ± 15 ± 15 IRMIN ≤ IR ≤ 1 mA 0.7 IR= 10 mA IR = 1 mA 1 mA ≤ IR ≤ 12 mA Wideband Noise ± 1.2 ± 9.2 ± 2.4 ± 10.4 mV (max) 60 60 µA (max) 65 65 µA (max) ± 100 ± 100 ppm/˚C (max) IR = 100 µA mV (max) µA ppm/˚C ppm/˚C mV 1.5 1.5 mV (max) 2.0 2.0 mV (max) 6.0 6.0 mV (max) 8.0 8.0 mV (max) 1.5 1.5 Ω (max) 4.0 IR = 1 mA, f = 120 Hz, Units (Limit) V 45 mV Ω 0.5 IAC= 0.1 IR eN LM4041AIM3 LM4041BIM3 LM4041AIZ LM4041BIZ Limits LM4041BIM7 (Note 5) Limits (Note 5) 20 µVrms 120 ppm 0.08 % 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 10) www.national.com ∆T = −40˚C to +125˚C 4 LM4041 LM4041-1.2 Electrical Characteristics (Industrial Temperature Range) (Continued) LM4041-1.2 Electrical Characteristics (Industrial Temperature Range) Boldface limits apply for TA = TJ = TMINto TMAX; all other limits TA = TJ = 25˚C. The grades C, D and E designate initial Reverse Breakdown Voltage tolerances of ± 0.5%, ± 1.0% and ± 2.0%, respectively. Symbol VR Parameter Conditions Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage IR = 100 µA Typical (Note 4) 1.225 Tolerance (Note 6) IRMIN Minimum Operating Current ∆VR/∆T VR Temperature Coefficient (Note 6) ∆VR/∆IR Reverse Breakdown Voltage Change with Operating Current Change (Note 9) IR= 100 µA ± 20 ± 15 ± 15 IRMIN ≤ IR ≤ 1 mA 0.7 IR = 10 mA IR = 1 mA Reverse Dynamic Impedance IR = 1 mA, f = 120 Hz ±6 ± 12 ± 25 mV (max) ± 14 ± 24 ± 36 mV (max) Wideband Noise IR = 100 µA µA 60 65 65 µA (max) 65 70 70 µA (max) ± 100 ± 150 ± 150 ppm/˚C (max) ppm/˚C ppm/˚C mV 1.5 2.0 2.0 mV (max) 2.0 2.5 2.5 mV (max) 6.0 8.0 8.0 mV (max) 8.0 10.0 10.0 mV (max) 2.5 mV Ω 0.5 IAC = 0.1 IR eN Units (Limit) V 45 1 mA ≤ IR ≤ 12 mA ZR LM4041CIM3 LM4041DIM3 LM4041EIM3 LM4041CIZ LM4041DIZ LM4041EIZ LM4041CIM7 LM4041DIM7 LM4041EIM7 Limits Limits (Note Limits (Note 5) 5) (Note 5) 1.5 2.0 2.0 Ω(max) 20 µVrms 120 ppm 0.08 % 5 www.national.com 10 Hz ≤ f ≤ 10 kHz ∆VR VHYST Reverse Breakdown Voltage Long Term Stability Thermal Hysteresis (Note 10) t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA ∆T = −40˚C to +125˚C LM4041 LM4041-1.2 Electrical Characteristics (Extended Temperature Range) Boldface limits apply for TA = TJ = TMINto TMAX; all other limits TA = TJ = 25˚C. The grades C, D and E designate initial Reverse Breakdown Voltage tolerance of ± 0.5%, ± 1.0% and ± 2.0% respectively. Symbol VR Parameter Conditions Reverse Breakdown Voltage IR = 100 µA Reverse Breakdown Voltage Error IR = 100 µA Typical LM4041CEM3 LM4041DEM3 LM4041EEM3 (Note 4) Limits Limits Limits (Note 5) (Note 5) (Note 5) 1.225 (Note 6) IRMIN Minimum Operating Current ∆VR/∆T VR Temperature Coefficient(Note 6) ∆VR/∆IR Reverse Breakdown Change with Current (Note 9) ZR Reverse Dynamic Impedance eN Noise Voltage V ±6 ± 12 ± 25 mV (max) ± 18.4 ± 31 ± 43 mV (max) 60 65 65 µA (max) 68 73 73 µA (max) ± 100 ± 150 ± 150 ppm/˚C (max) 45 IR = 1 mA ± 20 ± 15 IR = 100 µA ± 15 IRMIN ≤ IR ≤ 1.0 mA 0.7 IR= 10 mA 1 mA ≤ IR ≤ 12 mA IR = 1 mA, f = 120 Hz, IR = 100 µA µA ppm/˚C ppm/˚C mV 1.5 2.0 2.0 mV (max) 2.0 2.5 2.5 mV (max) 6.0 8.0 8.0 mV (max) 8.0 10.0 10.0 mV (max) 2.5 mV Ω 0.5 IAC= 0.1 IR Units (Limit) 1.5 2.0 2.0 Ω (max) 20 µVrms 120 ppm 0.08 % 10 Hz ≤ f ≤ 10 kHz ∆VR Long Term Stability (Non-Cumulative) t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA VHYST Thermal Hysteresis (Note 10) www.national.com ∆T = −40˚C to +125˚C 6 LM4041 LM4041-ADJ (Adjustable) Electrical Characteristics (Industrial Temperature Range) Boldface limits apply for TA = TJ = TMINto TMAX; all other limits TJ = 25˚C unless otherwise specified (SOT-23, see (Note 7)), IRMIN ≤ IR ≤ 12 mA, VREF ≤ VOUT ≤ 10V. The grades C and D designate initial Reference Voltage Tolerances of ± 0.5% and ± 1%, respectively for VOUT = 5V. Symbol VREF Parameter Conditions Typical (Note 4) Reference Voltage IR = 100 µA, VOUT = 5V Reference Voltage IR = 100 µA, VOUT = 5V ∆VREF/∆IR Minimum Operating Current Reference Voltage Change with Operating Current Change (Note 9) IFB ∆VREF/∆T ZOUT eN IRMIN ≤ IR ≤ 1 mA ± 6.2 ± 14 ± 12 ± 24 mV (max) 60 65 µA (max) 65 70 µA (max) 1.5 2.0 mV (max) 2.0 2.5 mV (max) V (Note 7) 1 mA ≤ IR ≤ 12 mA mV 2 IR = 1 mA mV 4 6 mV (max) 6 8 mV (max) −1.55 mV/V −2.0 −2.5 mV/V (max) −2.5 −3.0 mV/V (max) 100 150 nA (max) 120 200 nA (max) 60 Average Reference Voltage Temperature Coefficient (Note 8) VOUT = 5V, IR = 10 mA Dynamic Output Impedance IR = 1 mA, f = 120 Hz, IR = nA 20 1 mA 15 IR = 100 µA 15 mV (max) µA 0.7 SOT-23: VOUT ≥ 1.6V Feedback Current Wideband Noise Units (Limit) 45 SOT-23: VOUT ≥ 1.6V (Note 7) ∆VREF/∆VO Reference Voltage Change with Output Voltage Change LM4041DIM3 LM4041DIZ LM4041DIM7 (Note 5) 1.233 Tolerance (Note 8) IRMIN LM4041CIM3 LM4041CIZ LM4041CIM7 (Note 5) ppm/˚C ± 100 ± 150 ppm/˚C (max) ppm/˚C IAC = 0.1 IR IR = 100 µA VOUT = VREF 0.3 Ω VOUT = 10V 2 Ω VOUT = VREF 20 µVrms 120 ppm 10 Hz ≤ f ≤ 10 kHz ∆VREF VHYST Reference Voltage Long t = 1000 hrs, Term Stability T = 25˚C ± 0.1˚C IR = 100 µA Thermal Hysteresis (Note 10) ∆T = −40˚C to +125˚C 0.08 7 % www.national.com LM4041 LM4041-ADJ (Adjustable) Electrical Characteristics (Extended Temperature Range) Boldface limits apply for TA = TJ = TMINto TMAX; all other limits TJ = 25˚C unless otherwise specified (SOT-23, see (Note 7)), IRMIN ≤ IR ≤ 12 mA, VREF ≤ VOUT ≤ 10V. The grades C and D designate initial Reference Voltage Tolerances of ± 0.5% and ± 1%, respectively for VOUT = 5V. Symbol VREF Parameter Conditions Typical (Note 4) Reference Voltage IR = 100 µA, VOUT = 5V Reference Voltage IR = 100 µA, VOUT = 5V 1.233 Tolerance (Note 8) IRMIN ∆VREF/∆IR Minimum Operating Current Reference Voltage Change with Operating Current Change (Note 9) IRMIN ≤ IR ≤ 1 mA IFB ∆VREF/∆T ZOUT eN (Note 7) 1 mA ≤ IR ≤ 12 mA mV (max) 60 65 µA (max) 68 73 µA (max) 1.5 2.0 mV (max) 2.0 2.5 mV (max) IR = 1 mA mV mV 8 10 mV (max) 6 8 mV (max) −1.55 mV/V −2.0 −2.5 mV/V (max) −3.0 −4.0 mV/V (max) 100 150 nA (max) 120 200 nA (max) 60 Average Reference Voltage Temperature Coefficient (Note 8) VOUT = 5V, Dynamic Output Impedance IR = 1 mA, f = 120 Hz, mV (max) µA 2 Feedback Current Wideband Noise V ± 12 ± 30 0.7 SOT-23: VOUT ≥ 1.6V Units (Limit) ± 6.2 ± 18 45 SOT-23: VOUT ≥ 1.6V(Note 7) ∆VREF/∆VO Reference Voltage Change with Output Voltage Change LM4041CEM3 LM4041DEM3 (Note 5) (Note 5) nA IR = 10 mA 20 ppm/˚C IR = 1 mA 15 IR = 100 µA 15 ppm/˚C ± 100 ± 150 ppm/˚C (max) IAC = 0.1 IR IR = 100 µA VOUT = VREF 0.3 Ω VOUT = 10V 2 Ω VOUT = VREF 20 µVrms 120 ppm 10 Hz ≤ f ≤ 10 kHz ∆VREF VHYST Reference Voltage Long t = 1000 hrs, Term Stability T = 25˚C ± 0.1˚C Thermal Hysteresis (Note 10) ∆T = −40˚C to +125˚C www.national.com IR = 100 µA 0.08 8 % LM4041 LM4041-ADJ (Adjustable) Electrical Characteristics (Extended Temperature Range) (Continued) 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 LM4041, TJmax = 125˚C, and the typical thermal resistance (θJA), when board mounted, is 326˚C/W for the SOT-23 package, 415˚C/W for the SC70 package and 180˚C/W with 0.4" lead length and 170˚C/W with 0.125" lead length for the TO-92 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. All pins are rated at 2kV for Human Body Model, but the feedback pin which is rated at 1kV. 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 ± [(∆VRv∆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 MAX or TMIN, 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: B-grade: C-grade: D-grade: E-grade: ± 0.75% = ± 0.1% ± 100 ppm/˚C x 65˚C ± 0.85% = ± 0.2% ± 100 ppm/˚C x 65˚C ± 1.15% = ± 0.5% ± 100 ppm/˚C x 65˚C ± 1.98% = ± 1.0% ± 150 ppm/˚C x 65˚C ± 2.98% = ± 2.0% ± 150 ppm/˚C x 65˚C The total over-temperature tolerance for the different grades in the extended temperature range where max ∆T = 100 ˚C is shown below: B-grade: C-grade: D-grade: E-grade: ± 1.2% = ± 0.2% ± 100 ppm/˚C x 100˚C ± 1.5% = ± 0.5% ± 100 ppm/˚C x 100˚C ± 2.5% = ± 1.0% ± 150 ppm/˚C x 100˚C ± 4.5% = ± 2.0% ± 150 ppm/˚C x 100˚C Therefore, as an example, the A-grade LM4041-1.2 has an over-temperature Reverse Breakdown Voltage tolerance of ± 1.2V x 0.75% = ± 9.2 mV. Note 7: When VOUT ≤ 1.6V, the LM4041-ADJ in the SOT-23 package must operate at reduced IR. This is caused by the series resistance of the die attach between the die (-) output and the package (-) output pin. See the Output Saturation (SOT-23 only) curve in the Typical Performance Characteristics section. Note 8: Reference voltage and temperature coefficient will change with output voltage. See Typical Performance Characteristics curves. Note 9: Load regulation is measured on pulse basis from no load to the specified load current. Ouput changes due to die temperature change must be taken into account separately.Note 10: 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. 9 www.national.com LM4041 Typical Performance Characteristics Temperature Drift for Different Average Temperature Coefficient Output Impedance vs Frequency 01139219 01139204 Noise Voltage Reverse Characteristics and Minimum Operating Current 01139205 01139209 Start-Up Characteristics 01139208 01139207 www.national.com 10 LM4041 Typical Performance Characteristics (Continued) Reference Voltage vs Output Voltage and Temperature Reference Voltage vs Temperature and Output Voltage 01139211 01139210 Feedback Current vs Output Voltage and Temperature Output Saturation (SOT-23 Only) 01139233 01139212 Output Impedance vs Frequency Output Impedance vs Frequency 01139213 01139214 11 www.national.com LM4041 Typical Performance Characteristics (Continued) Reverse Characteristics 01139216 01139215 Large Signal Response 01139218 01139217 Functional Block Diagram 01139221 *LM4041-ADJ only **LM4041-1.2 only www.national.com 12 The LM4041 is a precision micro-power curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4041 is available in the sub-miniature SOT-23 and SC70 surface-mount package. The LM4041 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 LM4041 remains stable. Design effort is further reduced with the choice of either a fixed 1.2V or an adjustable reverse breakdown voltage. The minimum operating current is 60 µA for the LM4041-1.2 and the LM4041-ADJ. Both versions have a maximum operating current of 12 mA. VO = VREF[(R2/R1) + 1] (1) where VO is the output voltage. The actual value of the internal VREF is a function of VO. The “corrected” VREF is determined by (2) VREF = ∆VO (∆VREF/∆VO) + VY where VY = 1.240 V and ∆VO = (VO − VY) ∆VREF/∆VO is found in the Electrical Characteristics and is typically −1.55 mV/V. You can get a more accurate indication of the output voltage by replacing the value of VREF in equation (1) with the value found using equation (2). LM4041s using the SOT-23 package have pin 3 connected as the (-) output through the package’s die attach interface. Therefore, the LM4041-1.2’s pin 3 must be left floating or connected to pin 2 and the LM4041-ADJ’s pin 3 is the (-) output. Note that the actual output voltage can deviate from that predicted using the typical value of ∆VREF/∆VO in equation (2): for C-grade parts, the worst-case ∆VREF/∆VO is −2.5 mV/V. For D-grade parts, the worst-case ∆VREF/∆VO is −3.0 mV/V. LM4041s using the SC70 package have pin 2 connected as the (−) output through the packages’ die attach interface. Therefore, the LM4041-1.2’s pin 2 must be left floating or connected to pin 1, and the LM4041-ADJ’s pin 2 is the (−) output. Typical Applications 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 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 LM4041. RS determines the current that flows through the load (IL) and the LM4041 (IQ). Since load current and supply voltage may vary, RS should be small enough to supply at least the minimum acceptable IQ to the LM4041 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 LM4041 is less than 12 mA. RS should be selected based on the supply voltage, (VS), the desired load and operating current, (IL and IQ), and the LM4041’s reverse breakdown voltage, VR. 01139222 FIGURE 1. Shunt Regulator 01139234 VO = VREF[(R2/R1) + 1] The LM4041-ADJ’s output voltage can be adjusted to any value in the range of 1.24V through 10V. It is a function of the internal reference voltage (VREF) and the ratio of the external FIGURE 2. Adjustable Shunt Regulator 13 www.national.com LM4041 feedback resistors as shown in Figure 2 . The output voltage is found using the equation Applications Information LM4041 Typical Applications (Continued) 01139224 FIGURE 3. Bounded amplifier reduces saturation-induced delays and can prevent succeeding stage damage. Nominal clamping voltage is ± VO (LM4041’s reverse breakdown voltage) +2 diode VF. 01139223 01139220 FIGURE 5. Voltage Level Detector FIGURE 4. Voltage Level Detector www.national.com 14 LM4041 Typical Applications (Continued) 01139236 FIGURE 9. Bidirectional Adjustable Clamp ± 2.4V to ± 6V 01139225 FIGURE 6. Fast Positive Clamp 2.4V + VD1 01139226 FIGURE 7. Bidirectional Clamp ± 2.4V 01139235 FIGURE 8. Bidirectional Adjustable Clamp ± 18V to ± 2.4V 15 www.national.com LM4041 Typical Applications (Continued) 01139237 FIGURE 10. Simple Floating Current Detector 01139238 FIGURE 11. Current Source Note 11: *D1 can be any LED, VF = 1.5V to 2.2V at 3 mA. D1 may act as an indicator. D1 will be on if ITHRESHOLDfalls below the threshold current, except with I = 0. www.national.com 16 LM4041 Typical Applications (Continued) 01139239 FIGURE 12. Precision Floating Current Detector 01139229 01139228 FIGURE 13. Precision 1 µA to 1 mA Current Sources 17 www.national.com LM4041 Physical Dimensions inches (millimeters) unless otherwise noted Plastic Surface Mount Package (M3) NS Package Number MF03A (JEDEC Registration TO-236AB) Molded Package (SC70) NS Package Number MAA05A www.national.com 18 LM4041 Precision Micropower Shunt Voltage Reference Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Plastic Package (Z) NS Package Number Z03A 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. For the most current product information visit us at www.national.com. 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