www.fairchildsemi.com KA431S/KA431SA/KA431SL Programmable Shunt Regulator Features Description • • • • The KA431S/KA431SA/KA431SL are three-terminal adjustable regulator series with a guaranteed thermal stability over applicable temperature ranges. The output voltage may be set to any value between VREF (approximately 2.5 volts) and 36 volts with two external resistors These devices have a typical dynamic output impedance of 0.2Ω. Active output circuitry provides a very sharp turn on characteristic, making these devices excellent replacement for zener diodes in many applications. Programmable Output Voltage to 36 Volts Low Dynamic Output Impedance 0.2Ω Typical Sink Current Capability of 1.0 to 100mA Equivalent Full-Range Temperature Coefficient of 50ppm/°C Typical • Temperature Compensated for Operation Over Full Rated Operating Temperature Range • Low Output Noise Voltage • Fast Turn-on Response SOT-23F 3 1 2 MF- 1.Cathode 2. Ref 3. Anode MF2- 1. Ref 2. Cathode 3. Anode Internal Block Diagram CATHODE + REFERENCE 2.5 Vref ANODE CATHODE (K) REFERENCE (R) ANODE(A) Rev. 1.0.7 ©2011 Fairchild Semiconductor Corporation KA431S/KA431SA/KA431SL Absolute Maximum Ratings (Operating temperature range applies unless otherwise specified.) Parameter Symbol Value Unit Cathode Voltage VKA 37 V Cathode Current Range (Continuous) IKA -100 ~ +150 mA Reference Input Current Range IREF -0.05 ~ +10 mA Thermal Resistance Junction-Air (Note1,2) MF Suffix Package RθJA 350 °C/W Power Dissipation (Note3,4) MF Suffix Package PD 350 mW Junction Temperature TJ 150 °C Operating Temperature Range TOPR -25 ~ +85 °C Storage Temperature Range TSTG -65 ~ +150 °C Note : 1. Thermal resistance test board Size: 76.2mm * 114.3mm * 1.6mm (1S0P) JEDEC Standard: JESD51-3, JESD51-7 2. Assume no ambient airflow. 3. TJMAX = 150°C, Ratings apply to ambient temperature at 25°C 4. Power dissipation calculation: PD = (TJ - TA)/RθJA Recommended Operating Conditions Parameter 2 Symbol Min. Typ. Max. Unit Cathode Voltage VKA VREF - 36 V Cathode Current IKA 1.0 - 100 mA KA431S/KA431SA/KA431SL Electrical Characteristics (TA = +25°C, unless otherwise specified) Parameter Symbol Reference Input Voltage VREF Deviation of Reference Input Voltage OverTemperature ΔVREF/ ΔT Conditions VKA=VREF, IKA=10mA VKA=VREF, IKA=10mA TMIN≤TA≤TMAX Min. KA431S KA431SA Typ. Max. Min. Typ. Max. Min. 2.450 2.500 KA431SL Typ. Max. 2.550 2.470 2.495 2.520 2.482 2.495 2.508 - 4.5 17 - 4.5 17 - 4.5 17 ΔVKA=10 V-VREF - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7 ΔVKA=36 V-10V - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0 Unit V mV Ratio of Change ΔVREF/ ΔVKA in Reference Input Voltage to the Change in Cathode Voltage IKA =10mA Reference Input Current IKA=10mA, R1=10kΩ,R2=∞ - 1.5 4 - 1.5 4 - 1.5 4 μA Deviation of Reference Input Current Over Full Temperature Range IKA=10mA, R1=10kΩ,R2=∞ ΔIREF/ΔT TA =Full Range - 0.4 1.2 - 0.4 1.2 - 0.4 1.2 μA Minimum Cathode Current for Regulation IKA(MIN) VKA=VREF - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA Off - Stage Cathode Current IKA(OFF) VKA=36V, VREF=0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0 μA VKA=VREF, IKA=1 to 100mA f ≥1.0kHz - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Ω Dynamic Impedance IREF ZKA mV/V • TMIN = -25°C, TMAX = +85°C 3 KA431S/KA431SA/KA431SL Test Circuits KA431S KA431S Figure 1. Test Circuit for VKA=VREF KA431S Figure 3. Test Circuit for lKA(OFF) 4 Figure 2. Test Circuit for VKA≥VREF KA431S/KA431SA/KA431SL Typical Performance Characteristics 800 150 VKA = VREF o VKA = VREF TA = 25 C o TA = 25 C 600 IKA, CATHODE CURRENT (uA) IK, Cathode Current (mA) 100 50 0 IKA(MIN) 400 200 0 -50 -200 -100 -2 -1 0 1 2 -1 3 0 1 2 3 VKA, CATHODE VOLTAGE (V) VKA, Cathode Voltage (V) Figure 4. Cathode Current vs. Cathode Voltage Figure 5. Cathode Current vs. Cathode Voltage 3.5 0.100 Iref, Reference Input Current (uA) Ioff, Off-State Cathode Current (uA) 3.0 0.075 0.050 0.025 0.000 -50 -25 0 25 50 75 100 2.5 2.0 1.5 1.0 0.5 0.0 -50 125 -25 0 o 25 50 75 100 125 o TA, Ambient Temperature ( C) TA, Ambient Temperature ( C) Figure 6. OFF-State Cathode Current vs. Ambient Temperature Figure7. Reference Input Current vs. Ambient Temperature 6 60 o TA = 25 C IKA = 10mA 50 o TA=25 C 5 INPUT 4 Voltage Swing (V) Open Loop Voltage Gain (dB) 40 30 20 3 OUTPUT 2 10 1 0 0 -10 1k 10k 100k 1M 10M Frequency (Hz) Figure 8. Small Signal Voltage Amplification vs. Frequency 0 4 8 12 16 20 Time (us) Figure 9. Pulse Response 5 KA431S/KA431SA/KA431SL Typical Performance Characteristics (Continued) 5 140 A VKA = Vref B VKA = 5.0 V @ IK = 10mA 120 4 o A 100 Current(mA) IK, CATHODE CURRENT(mA) TA = 25 C 80 stable stable 60 3 2 40 1 20 B 0 100p 1n 10n 1ٛ 100n 10ٛ CL, LOAD CAPACITANCE 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Anode-Ref. Voltage(V) Figure 10. Stability Boundary Conditions 5 Current(mA) 4 3 2 1 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Ref.-Cathode Voltage(V) Figure 12. Reference-Cathode Diode Curve 6 Figure 11. Anode-Reference Diode Curve KA431S/KA431SA/KA431SL Typical Application R1 V O = V ref ⎛⎝ 1 + -------⎞⎠ R2 R1 V O = ⎛ 1 + -------⎞ V ref ⎝ R 2⎠ KA431S R1 V O = ⎛ 1 + -------⎞ V ref ⎝ R 2⎠ KA431S KA431S Figure 13. Shunt Regulator - Figure 14. Output Control for Figure 15. High Current Shunt Regulator Three-Termianl Fixed Regulator KA431S Figure 16. Current Limit or Current Source KA431S Figure 17. Constant-Current Sink 7 KA431S/KA431SA/KA431SL Mechanical Dimensions Package Dimensions in millimeters SOT-23F Marking MF- MF2- 8 43A 43B 2% tolerance 1% tolerance 43A 43D 43E 43B 2% tolerance 1% tolerance 43C 0.5% tolerance 43C 43F 0.5% tolerance KA431S/KA431SA/KA431SL Ordering Information Product Number Output Voltage Tolerance Package KA431SLMF 0.5% SOT-23F KA431SAMF 1% SOT-23F KA431SMF 2% SOT-23F KA431SLMF2 0.5% SOT-23F KA431SAMF2 1% SOT-23F KA431SMF2 2% SOT-23F Operating Temperature -25 ~ +85°C 9 KA431S/KA431SA/KA431SL DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. 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