TL431 Programmable voltage reference Features ■ Adjustable output voltage: 2.5 to 36 V ■ Sink current capability: 1 to 100 mA ■ Typical output impedance: 0.22 Ω ■ 1% and 2% voltage precision Z TO-92 (Plastic package) Description The TL431 is a programmable shunt voltage reference with guaranteed temperature stability over the entire operating temperature range. D SO-8 (Batwing plastic micropackage) The output voltage may be set to any value between 2.5 V and 36 V with two external resistors. The TL431 operates with a wide current range from 1 to 100 mA with a typical dynamic impedance of 0.22 Ω. March 2008 Rev 5 1/15 www.st.com 15 Schematic diagrams 1 TL431 Schematic diagrams Figure 1. TO-92 pin connections (top view) Cathode Anode Reference 1 Figure 2. 2 3 SO-8 batwing pin connections (top view) 8 7 6 5 1 - Cathode 2 - Anode 3 - Anode 4 - N.C. 5 - N.C. 6 - Anode 7 - Anode 8 - Reference 1 Figure 3. 2 3 4 TL431 block diagram Cathode Vref + Vref Anode 2/15 TL431 2 Absolute maximum ratings and operating conditions Absolute maximum ratings and operating conditions Table 1. Absolute maximum ratings Symbol VKA Parameter Cathode to anode voltage Value Unit 37 V Ik Continuous cathode current range -100 to +150 mA Iref Reference input current range -0.05 to +10 mA 625 960 mW Pdiss Power dissipation (1) TO-92 SO-8 batwing Tstg Storage temperature range -65 to +150 °C HBM: human body model (2) 2000 200 1500 V ESD MM: machine model (3) CDM: charged device model (4) 1. Pdiss is calculated with Tamb = +25° C, Tj = +150° C and Rthja = 200° C/W for TO-92 package Rthja = 130° C/W for SO-8 batwing package 2. Human body model: A 100 pF capacitor is charged to the specified voltage, then discharged through a 1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating. 3. Machine model: A 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations while the other pins are floating. 4. Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly to the ground through only one pin. This is done for all pins. Table 2. Operating conditions Symbol VKA Ik Toper Parameter Value Unit Cathode to anode voltage Vref to 36 V Cathode current 1 to 100 mA 0 to +70 -40 to +105 °C Operating free-air temperature range TL431C/AC TL431I/AI 3/15 Electrical characteristics TL431 3 Electrical characteristics Table 3. Tamb = 25°C (unless otherwise specified) TL431C Symbol Unit Min. Vref Reference input voltage VKA = Vref , Ik = 10 mA, Tamb = 25°C Tmin ≤ Tamb ≤ Tmax ΔVref Reference input voltage deviation over temperature range (1) VKA = Vref, Ik = 10 mA, Tmin ≤ Tamb ≤ Tmax ΔVref -----------ΔVka Iref TL431AC Parameter Typ. Max. Min. Typ. Max. 2.44 2.495 2.55 2.47 2.495 2.52 2.423 2.567 2.453 2.537 Ratio of change in reference input voltage to change in cathode to anode voltage Ik = 10mA - ΔVKA = 10V to Vref ΔVKA = 36V to 10V mV 3 -2.7 -2 Reference input current Ik = 10mA, R1 = 10kΩ, R2 = ∞ Tamb = 25°C Tmin ≤ Tamb ≤ Tmax 17 -1.4 -1 1.8 3 -2.7 -2 4 5.2 15 mV/V -1.4 -1 1.8 4 5.2 Reference input current deviation over temperature range Ik = 10mA, R1 = 10kΩ, R2 =∞ Tmin ≤ Tamb ≤ Tmax 0.4 1.2 0.4 1.2 Imin Minimum cathode current for regulation VKA = Vref 0.5 1 0.5 0.6 Ioff Off-state cathode current 2.6 1000 2.6 1000 0.22 0.5 0.22 0.5 ΔIref V µA µA mA nA (2) ⏐ ZKA⏐ Dynamic impedance VKA = Vref , Δ Ik = 1 to100mA, f ≤ 1kHZ 1. See definition of Reference input voltage deviation over temperature range. ΔV KA 2. The dynamic impedance is defined as | ZKA| = --------------- ΔI k 4/15 Ω TL431 Table 4. Electrical characteristics Tamb = 25°C (unless otherwise specified) TL431I Symbol Unit Min. Vref Reference input voltage VKA = Vref , Ik = 10 mA, Tamb = 25°C Tmin ≤ Tamb ≤ Tmax ΔVref Reference input voltage deviation over temperature range (1) VKA = Vref , Ik =10 mA, Tmin≤ Tamb≤ Tmax ΔVref -----------ΔVka Ratio of change in reference input voltage to change in cathode to anode voltage Ik = 10mA, ΔVKA = 10V to Vref ΔVKA = 36V to 10V Iref ΔIref TL431AI Parameter Reference input current Ik = 10mA, R1 = 10kΩ, R2 = ∞ Tamb = 25°C Tmin ≤ Tamb ≤Tmax Reference input current deviation over temperature range Ik = 10mA, R1 = 10kΩ, R2 = ∞ Tmin ≤ Tamb ≤ Tmax Typ. Max. Min. Typ. Max. 2.44 2.495 2.55 2.41 2.58 2.47 2.495 2.52 2.44 2.55 V 7 7 mV -2.7 -2 30 -1.4 -1 -2.7 -2 30 -1.4 -1 mV/V 1.8 4 6.5 1.8 4 6.5 µA 0.8 2.5 0.8 1.2 µA Imin Minimum cathode current for regulation VKA = Vref 0.5 1 0.5 0.7 mA Ioff Off-state cathode current 2.6 1000 2.6 1000 nA 0.22 0.5 0.22 0.5 Ω (2) ⏐ ZKA⏐ Dynamic impedance VKA = Vref , Δ Ik = 1 to100mA, f ≤ 1kHZ 1. See definition of Reference input voltage deviation over temperature range below. ΔV KA 2. The dynamic impedance is defined as | ZKA| = --------------- ΔI k Reference input voltage deviation over temperature range ΔVref is defined as the difference between the maximum and minimum values obtained over the full temperature range. ΔVref = Vref max - Vref min Figure 4. Reference input voltage deviation over temperature range V ref max. V ref min. T1 T2 Temperature 5/15 Electrical characteristics Figure 5. TL431 Test circuit for VKA = Vref Figure 6. Test circuit for programming mode Input Input R Output R IK Output R1 IK=10mA VKA IREF R2 VKA VREF VREF R1 VKA = VREF ( 1 + -------- ) + R1 x IREF R2 Figure 7. Test circuit for Ioff Figure 8. Test circuit for phase margin and voltage gain VKA=36V 10μF 10μF Test circuit for response time 1 mA 0 mA 6/15 Output IK=1mA Output Figure 9. 8.25kΩ Input IK=10mA 15kΩ IOFF VREF TL431 Electrical characteristics Figure 10. Reference voltage vs. temperature Figure 11. Reference voltage vs. cathode current 100 Cathode current IKA (mA) Cathode voltage VKA (V) 2.54 VKA = VREF IK = 10 mA 2.52 2.50 2.48 2.46 2.44 -40 TAMB=+25°C 75 50 25 0 -25 -50 -20 0 20 40 60 80 100 -1 0 Temperature (°C) Figure 12. Reference voltage vs. cathode current Reference current IREF (μA) Cathode current IKA (mA) 3 2.0 TAMB = +25°C 1 0 -1 IK=10 mA R1=10kΩ R2= + ∝ 1.5 1.0 0.5 -2 -1 0 1 2 0.0 −40 3 −20 0 Cathode voltage VKA (V) 20 40 60 80 100 Temperature °C Figure 14. Off-state cathode current vs. temperature Figure 15. Ratio of change in Vref to change in VKA vs. temperature 2.0 0.0 VKA = 36 V VREF = 0 V ΔVREF / ΔVKA (mV / V) Off-state current IOFF (μA) 2 Figure 13. Reference current vs. temperature 2 1.5 1.0 -0.5 IK = 10 mA -1.0 -1.5 0.5 0.0 -40 1 Cathode voltage VKA (V) -20 0 20 40 Temperature (°C) 60 80 100 -2.0 -40 -20 0 20 40 60 80 100 Temperature (°C) 7/15 Electrical characteristics TL431 Figure 16. Static impedance RKA vs. temperature Figure 17. Minimum operating current vs. temperature 0.6 Minimum cathode current IMIN (mA) Static impedance RKA (Ω) 0.30 0.28 VKA=VREF TAMB=+25°C 0.26 0.24 0.22 0.20 -40 -20 0 20 40 60 80 0.4 0.0 -40 100 VKA = VREF 0.2 -20 0 Figure 18. Gain and phase vs. frequency 50 Phase 0 0 -50 Phase (°) Gain (dB) 80 100 VKA=VREF 150 100 20 60 100 Cathode current (mA) IK=10 mA See figure 4 40 40 Figure 19. Stability behavior with capacitive loads 200 60 Gain 20 Temperature (°C) Temperature (°C) 80 VKA=5 V Instable Area 60 40 VKA=12 V 20 VKA=24 V -100 -20 -150 -40 1 10 100 -200 10000 1000 0 1E-10 1E-9 Frequency (kHz) Figure 20. Maximum power dissipation 60 TO92 40 Safe Area Input and Output voltage (V) Cathode current (mA) SO8 Batwing 80 1E-5 Input 20 30 VKA=VREF TAMB=+25°C 4 Output 2 0 10 Cathode voltage (V) 8/15 1E-6 6 TAMB= +25°C 0 1E-7 Figure 21. Pulse response for Ik = 1 mA 100 20 1E-8 Capacitive load (Farad) 0 2 4 6 Time (μs) 8 10 TL431 4 Package information Package information In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com. 9/15 Package information 4.1 TL431 SO-8 package information Figure 22. SO-8 package mechanical drawing Table 5. SO-8 package mechanical data Dimensions Ref. Millimeters Min. Typ. A Max. Min. Typ. 1.75 0.25 Max. 0.069 A1 0.10 A2 1.25 b 0.28 0.48 0.011 0.019 c 0.17 0.23 0.007 0.010 D 4.80 4.90 5.00 0.189 0.193 0.197 E 5.80 6.00 6.20 0.228 0.236 0.244 E1 3.80 3.90 4.00 0.150 0.154 0.157 e 0.004 0.010 0.049 1.27 0.050 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k 1° 8° 1° 8° ccc 10/15 Inches 0.10 0.004 TL431 TO-92 ammopack and tape and reel package information Figure 23. TO-92 ammopack and tape and reel package mechanical drawing A1 P T P A H W2 W0 W L1 W1 H0 H I1 d H1 4.2 Package information D0 F1 F2 P2 P0 Table 6. TO-92 ammopack and tape and reel package mechanical data Millimeters Inches Dim. Min Typ. Max. Min. Typ. Max. AL 5.0 0.197 A 5.0 0.197 T 4.0 0.157 d 0.45 0.018 I1 2.5 0.098 P 11.7 12.7 13.7 0.461 0.500 0.539 PO 12.4 12.7 13 0.488 0.500 0.512 P2 5.95 6.35 6.75 0.234 0.250 0.266 F1/F2 2.4 2.5 2.8 0.094 0.098 0.110 Δh -1 0 1 -0.039 0 0.039 ΔP -1 0 1 -0.039 0 0.039 W 17.5 18.0 19.0 0.689 0.709 0.748 W0 5.7 6 6.3 0.224 0.236 0.248 W1 8.5 9 9.75 0.335 0.354 0.384 W2 0.5 0.020 H 20 0.787 H0 15.5 16 H1 DO L1 16.5 0.610 0.630 25 3.8 4.0 4.2 11 0.650 0.984 0.150 0.157 0.165 0.433 11/15 Package information 4.3 TL431 TO-92 (bulk) package information Figure 24. TO-92 bulk package mechanical drawing Table 7. TO-92 bulk package mechanical data Millimeters Inches Dim. Min L 12/15 Typ. Max. Min. 1.27 Typ. Max. 0.05 B 3.2 3.7 4.2 0.126 0.1457 0.1654 O1 4.45 5.00 5.2 0.1752 0.1969 0.2047 C 4.58 5.03 5.33 0.1803 0.198 0.2098 K 12.7 O2 0.407 0.0197 0.02 a 0.35 0.5 0.5 0.508 0.016 0.0138 TL431 Ordering information 5 Ordering information Table 8. Order codes Order code Temperature range Package Packing SO-8 Tube or Tape and reel TL431CD TL431CDT 431C TL431ACD TL431ACDT TL431CZ TL431CZT TL431CZ-AP 431AC 0°C to +70°C TL431C TO-92 TL431ACZ TL431ACZT TL431ACZ-AP Bulk or Tape or Ammopack TL431AC TL431ID TL431IDT 431I SO-8 TL431AID TL431AIDT Tube or tape and reel 431AI TL431IZ TL431IZT TL431IZ-AP TL431I -40°C to + 105°C TO-92 TL431AIZ TL431AIZT TL431AIZ-AP Bulk or Tape or Ammopack TL431AI TL431IYD(1) TL431IYDT(1) TL431AIYD(1) TL431AIYDT(1) Marking 431IY SO-8 (automotive grade level) Tube or tape and reel 431AIY 1. Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC Q001 & Q 002 or equivalent are on-going. 13/15 Revision history TL431 6 Revision history Table 9. Document revision history Date Revision 01-Mar-2002 1 Initial release. 01-Nov-2005 2 PPAP references inserted in order codes table on cover page. 13-Dec-2006 3 Corrected TO-92 package information. 4 Specified that SO-8 package is batwing package. In electrical characteristics tables, moved negative values from max column to min column. Corrected captions of Figure 5 and of Figure 16. Added footnote to Table 8: Order codes. 5 Corrected SO-8 package mechanical data. Corrected footnote for automotive grade order codes in order code table. Corrected packing information for TO-92 devices in order code table. 08-Jun-2007 25-Feb-2008 14/15 Changes TL431 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. 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