LM4051 Precision Micropower Shunt Voltage Reference General Description Key Specifications (LM4051-1.2) Ideal for space critical applications, the LM4051 precision voltage reference is available in the sub-miniature (3 mm x 1.3 mm) SSOT-23 surface-mount package. The LM4051’s advanced design eliminates the need for an external stabilizing capacitor while ensuring stability with any capacitive load, thus making the LM4051 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 LM4051-1.2 and the LM4051-ADJ. Both versions have a maximum operating current of 12 mA. The LM4051 comes in three grades (A, B, and C). The best grade devices (A) have an initial accuracy of 0.1%, while the B-grade have 0.2% and the C-grade 0.5%, all with a tempco of 50 ppm/˚C guaranteed from −40˚C to 125˚C. The LM4051 utilizes fuse and zener-zap trim of reference voltage during wafer sort to ensure that the prime parts have an accuracy of better than ± 0.1% (A grade) at 25˚C. n Output voltage tolerance (A grade, 25˚C) Features n n n n Small packages: SSOT-23 No output capacitor required Tolerates capacitive loads Reverse breakdown voltage options of 1.225V and adjustable ± 0.1%(max) n Low output noise (10 Hz to 10kHz) 20µVrms n Wide operating current range 60µA to 12mA n Industrial temperature range (tempco guaranteed from −40˚C to +125˚C) −40˚C to +85˚C n Low temperature coefficient 50 ppm/˚C (max) Applications n n n n n n n n n n n Portable, Battery-Powered Equipment Data Acquisition Systems Instrumentation Process Control Energy Management Automotive and Industrial Precision Audio Components Base Stations Battery Chargers Medical Equipment Communication Connection Diagrams SSOT-23 DS101222-40 DS101222-1 *This pin must be left floating or connected to pin 2. Top View See NS Package Number MF03A © 2000 National Semiconductor Corporation DS101222 www.national.com LM4051 Precision Micropower Shunt Voltage Reference February 2000 LM4051 Ordering Information Reverse Breakdown Voltage Tolerance at 25˚C and Average Reverse Breakdown Voltage Temperature Coefficient LM4051 Supplied as 1000 Units, Tape and Reel ± 0.1%, 50 ppm/˚C max (A grade) ± 0.2%, 50 ppm/˚C max (B grade) LM4051 Supplied as 3000 Units, Tape and Reel LM4051AIM3-1.2 LM4051AIM3X-1.2 RIA LM4051AIM3-ADJ LM4051AIM3X-ADJ RHA LM4051BIM3-1.2 LM4051BIM3X-1.2 RIB LM4051BIM3-ADJ LM4051BIM3X-ADJ RHB LM4051CIM3-1.2 LM4051CIM3X-1.2 RIC LM4051CIM3-ADJ LM4051CIM3X-ADJ RHC ± 0.5%, 50 ppm/˚C max (C grade) SOT-23 Package Marking Information Only three fields of marking are possible on the SSOT-23’s small surface. This table gives the meaning of the three fields. Field Definition First Field: R = Reference Second Field: I = 1.225V Voltage Option H = Adjustable Third Field: A–C = Initial Reverse Breakdown Voltage or Reference Voltage Tolerance A = ± 0.1%, B = ± 0.2%, C = ± 0.5% www.national.com Part Marking 2 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. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Reverse Current Forward Current Maximum Output Voltage (LM4051-ADJ) Power Dissipation (TA = 25˚C) (Note 2) M3 Package Storage Temperature Lead Temperature M3 Packages Vapor phase (60 seconds) Infrared (15 seconds) 20 mA 10 mA Operating Ratings(Notes 1, 2) 15V Temperature Range Industrial Temperature Range Reverse Current LM4051-1.2 LM4051-ADJ Output Voltage Range LM4051-ADJ 280 mW −65˚C to +150˚C +215˚C +220˚C (Tmin ≤ TA ≤ Tmax) −40˚C ≤ TA ≤ +85˚C 60 µA to 12 mA 60 µA to 12 mA 1.24V to 10V LM4051-1.2 Electrical Characteristics Boldface limits apply for TA = TJ = TMINto 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 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 ∆VR/∆IR Minimum Operating Current IR= 10 mA Reverse Breakdown Voltage Change with Operating Current Change IRMIN ≤ IR ≤ 1 mA Reverse Dynamic Impedance eN Wideband Noise IR = 1 mA IR = 100 µA ∆T = −40˚C to 125˚C 1 mA ≤ IR ≤ 12 mA ± 20 ± 15 ± 15 Units (Limit) V ± 1.2 ± 2.4 ±6 mV (max) ± 5.2 ± 6.4 ± 10.1 mV (max) 39 Average Reverse Breakdown Voltage Temperature Coefficient (Note 6) ZR LM4051AIM3 LM4051BIM3 LM4051CIM3 (Limits) (Limits) Limts (Note 5) (Note 5) (Note 5) µA 60 60 60 µA (max) 65 65 65 µA (max) ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) 1.1 1.1 1.1 mV (max) 1.5 1.5 1.5 mV (max) 6.0 6.0 6.0 mV (max) 8.0 8.0 8.0 mV (max) 0.3 mV 1.8 mV IR = 1 mA, f = 120 Hz 0.5 Ω IR = 100 µA 20 µVrms 120 ppm 0.36 mV/V 10 Hz ≤ f ≤ 10 kHz ∆VR VHYST Reverse Breakdown Voltage Long Term Stability (Note 9) t = 1000 hrs T = 25˚C ± 0.1˚C IR = 100 µA Output Hysteresis (Note 10) ∆T = −40˚C to 125˚C 3 www.national.com LM4051 Absolute Maximum Ratings (Note 1) LM4051 LM4051-ADJ (Adjustable) Electrical Characteristics Boldface limits apply for TA = TJ = TMINto TMAX; all other limits TJ = 25˚C unless otherwise specified (SSOT-23, see (Note 7) , IRMIN ≤ IR ≤ 12 mA, VREF ≤ VOUT ≤ 10V. The grades A, B and C designate initial Reference Voltage Tolerances of ± 0.1%, ± 0.2% and ± 0.5%, respectively for VOUT = 5V. Symbol VREF IRMIN Parameter Reference Voltage IR = 100 µA, VOUT = 5V Reference Voltage Tolerance (Note 6), (Note 8) IR = 100 µA, VOUT = 5V ∆VREF/∆VO Reference Voltage Changewith Output Voltage Change ∆VREF/∆T Typical LM4051AIM3 LM4051BIM3 LM4051CIM3 (Note 4) (Note 5) (Note 5) (Note 5) 1.212 Minimum Operating Current ∆VREF/∆IR Reference VoltageChange with Operating Current Change IFB Conditions V ± 1.2 ± 5.2 ± 2.4 ± 6.4 ±6 ± 10.1 mV (max) mV (max) 60 65 60 65 65 70 µA µA (max) µA (max) 1.1 1.5 1.1 1.5 1.1 1.5 mV mV (max) mV(max) 6 8 6 8 6 8 mV mV (max) mV (max) −2.8 −3.5 −2.8 −3.5 −2.8 −3.5 mV/V mV/V (max) mV/V (max) 130 150 130 150 130 150 nA nA (max) nA (max) 36 IRMIN ≤ IR ≤ 1mA VOUT ≥ 1.6V (Note 7) 0.3 1 mA ≤ IR ≤ 12 mA VOUT ≥ 1.6V(Note 7) 0.6 IR = 0.1 mA −1.69 Feedback Current 70 Average ReferenceVoltage Temperature Coefficient (Note 8) VOUT = 2.5V Dynamic Output Impedance IR = 1 mA, f = 120 Hz, IAC = 0.1 IR IR = 10mA 20 IR = 1mA 15 IR = 100µA 15 Units (Limit) ppm/˚C ppm/˚C ± 50 ± 50 ± 50 ppm/˚C (max) ∆T = −40˚C to +125˚C ZOUT VOUT = VREF VOUT = 10V 0.3 2 Ω Ω eN Wideband Noise IR = 100 µA VOUT = VREF 10 Hz ≤ f ≤ 10 kHz 20 µVrms Reference Voltage Long Term Stability (Note 9) t = 1000 hrs, IR = 100 µA T = 25˚C ± 0.1˚C 120 ppm ∆VREF Output Hysteresis (Note 10) ∆T = −40˚C to +125˚C 0.3 mV/V VHYST www.national.com 4 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 LM4051, TJmax = 125˚C, and the typical thermal resistance (θJA), when board mounted, is 280˚C/W for the SSOT-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 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: ± 0.425% = ± 0.1% ± 50 ppm/˚C x 65˚C B-grade: ± 0.522% = ± 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 LM4051-1.2 has an over-temperature Reverse Breakdown Voltage tolerance of ± 1.2V x 0.425% = ± 5.2 mV. Note 7: When VOUT ≤ 1.6V, the LM4051-ADJ in the SSOT-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 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: Long term stability is VR @ 25˚C measured during 1000 hrs. Note 10: Thermal hysteresis is defined as the changes in 25˚C output voltage before and after cycling the device from −40˚C or +125˚C. Typical Performance Characteristics Temperature Drift for Different Average Temperature Coefficient Output Impedance vs Frequency DS101222-19 DS101222-4 5 www.national.com LM4051 Electrical Characteristics (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. LM4051 Typical Performance Characteristics (Continued) Noise Voltage Reverse Characteristics and Minimum Operating Current DS101222-5 DS101222-9 Start-Up Characteristics DS101222-8 DS101222-7 Reference Voltage vs Output Voltage and Temperature Reference Voltage vs Temperature and Output Voltage DS101222-11 www.national.com DS101222-10 6 (Continued) Feedback Current vs Output Voltage and Temperature Output Saturation (SOT-23 Only) DS101222-12 Output Impedance vs Frequency LM4051 Typical Performance Characteristics DS101222-33 Output Impedance vs Frequency DS101222-13 DS101222-14 Reverse Characteristics DS101222-16 DS101222-15 7 www.national.com LM4051 Typical Performance Characteristics (Continued) Large Signal Response DS101222-18 DS101222-17 Thermal Hysteresis DS101222-50 Functional Block Diagram DS101222-21 *LM4051-ADJ only **LM4051-1.2 only www.national.com 8 The LM4051 is a precision micro-power curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4051 is available in the sub-miniature SSOT-23 surface-mount package. The LM4051 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 LM4051 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 LM4051-1.2 and the LM4051-ADJ. Both versions have a maximum operating current of 12 mA. LM4051s using the SSOT-23 package have pin 3 connected as the (-) output through the package’s die attach interface. Therefore, the LM4051-1.2’s pin 3 must be left floating or connected to pin 2 and the LM4051-ADJ’s pin 3 is the (-) output. In a conventional shunt regulator application (Figure 1), an external series resistor (RS) is connected between the supply voltage and the LM4051. RS determines the current that flows through the load (IL) and the LM4051 (IQ). Since load current and supply voltage may vary, RS should be small enough to supply at least the minimum acceptable IQ to the LM4051 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 LM4051 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 LM4051’s reverse breakdown voltage, VR. where VO is the output voltage. The actual value of the internal VREF is a function of VO. The “corrected” VREF is determined by VREF = VO (∆VREF/∆VO) + VY (3) where VY = 1.22V ∆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 (3). Typical Applications DS101222-22 FIGURE 1. Shunt Regulator The LM4051-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 feedback resistors as shown in Figure 2 . The output voltage is found using the equation VO = VREF[(R2/R1) + 1] (1) DS101222-34 FIGURE 2. Adjustable Shunt Regulator (2) 9 www.national.com LM4051 Applications Information LM4051 Typical Applications (Continued) DS101222-24 FIGURE 3. Bounded amplifier reduces saturation-induced delays and can prevent succeeding stage damage. Nominal clamping voltage is ± VO (LM4051’s reverse breakdown voltage) +2 diode VF. DS101222-23 DS101222-20 FIGURE 5. Voltage Level Detector FIGURE 4. Voltage Level Detector www.national.com 10 LM4051 Typical Applications (Continued) DS101222-35 FIGURE 8. Bidirectional Adjustable Clamp ± 18V to ± 2.4V DS101222-25 FIGURE 6. Fast Positive Clamp 2.4V + VD1 DS101222-26 FIGURE 7. Bidirectional Clamp ± 2.4V DS101222-36 FIGURE 9. Bidirectional Adjustable Clamp ± 2.4V to ± 6V DS101222-37 FIGURE 10. Simple Floating Current Detector 11 www.national.com LM4051 Typical Applications (Continued) DS101222-38 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 = O. DS101222-39 FIGURE 12. Precision Floating Current Detector www.national.com 12 LM4051 Typical Applications (Continued) DS101222-28 DS101222-29 FIGURE 13. Precision 1 µA to 1 mA Current Sources 13 www.national.com LM4051 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. 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