Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS General Description Features The AN431 series ICs are three-terminal adjustable shunt regulators with guaranteed thermal stability over a full operation range. These ICs feature sharp turn-on characteristics, low temperature coefficient and low output impedance, which make them ideal substitutes for Zener diodes in applications such as switching power supply, charger and other adjustable regulators. · The output voltage of these ICs can be set to any value between VREF (2.5V) and the maximum cathode voltage (36V). The AN431 precision reference is offered in two voltage tolerance: 0.5% and 1.0%. · · · · · · · Programmable Precise Output Voltage from 2.5V to 36V High Stability under Capacitive Load Low Temperature Deviation: 4.5mV Typical Low Equivalent Full-range Temperature Coefficient with 20PPM/oC Typical Low Dynamic Output Resistance: 0.15Ω Typical Sink Current Capacity from 1mA to 100mA Low Output Noise Wide Operating Range of -40 to 125oC Applications · · · · · These ICs are available in SOT-23 package. AN431 Charger Voltage Adapter Switching Power Supply Graphic Card Precision Voltage Reference SOT-23 Figure 1. Package Type of AN431 Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 1 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Pin Configuration N Package (SOT-23) ANODE 3 2 1 CATHODE REF Figure 2. Pin Configuration of AN431 (Top View) Functional Block Diagram CATHODE 1 REF 2 + - VREF 3 ANODE Figure 3. Functional Block Diagram of AN431 Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 2 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Ordering Information AN431 - Circuit Type E1: Lead-Free Voltage Tolerance A: 0.5% B: 1.0% TR: Tape and Reel A: AN431 (40V) Package N: SOT-23 Package Temperature Range SOT-23 -40 to 125oC Voltage Tolerance Part Number Marking ID Packing Type 0.5% AN431AN-ATRE1 EB1 Tape & Reel 1.0% AN431BN-ATRE1 EB2 Tape & Reel BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 3 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Absolute Maximum Ratings (Note 1) Parameter Symbol Value Unit Cathode Voltage VKA 40 V Cathode Current Range (Continuous) IKA -100 to 150 mA Reference Input Current Range IREF 10 mA Power Dissipation PD 370 mW Junction Temperature TJ 150 oC Storage Temperature Range TSTG -65 to 150 oC ESD (Human Body Model) ESD 2000 V Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended periods may affect device reliability. Recommended Operating Conditions Parameter Symbol Min Max Unit Cathode Voltage VKA VREF 36 V Cathode Current IKA 1.0 100 mA -40 125 oC Operating Ambient Temperature Range Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 4 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Electrical Characteristics Operating Conditions: TA=25oC, unless otherwise specified. Parameter Reference Voltage 0.5% 1.0% Deviation of Reference Voltage Over Full Temperature Range Test Circuit Symbol 4 VREF 4 ∆VREF Conditions Min Typ Max 2.487 2.500 2.512 2.475 2.500 2.525 0 to 70oC 4.5 8 -40 to 85oC 4.5 10 -40 to 125oC 4.5 16 ∆VKA= 10V to VREF -1.0 -2.7 ∆VKA= 36V to 10V -0.5 -2.0 0.7 4 µA R2=∞, TA=-40 to 125oC 0.4 1.2 µA VKA=VREF, IKA=10mA VKA=VREF IKA=10mA Unit V mV Ratio of Change in Reference Voltage to the Change in Cathode Voltage 5 Reference Current 5 IREF Deviation of Reference Current Over Full Temperature Range 5 ∆IREF Minimum Cathode Current for Regulation 4 IKA (Min) VKA=VREF 0.4 1.0 mA Off-state Cathode Current 6 IKA (Off) VKA=36V, VREF=0 0.05 1.0 µA Dynamic Impedance 4 ZKA VKA=VREF, IKA=1 to 100mA, f ≤ 1.0kHz 0.15 0.5 Ω ∆VREF ∆VKA IKA=10mA IKA=10mA, R1=10KΩ, R2=∞ IKA=10mA, R1=10KΩ Mar. 2007 Rev. 1. 7 mV/V BCD Semiconductor Manufacturing Limited 5 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Electrical Characteristics (Continued) R1 VKA VIN IKA VREF Figure 4. Test Circuit 4 for VKA=VREF R3 VIN VKA IKA R1 IREF VKA=VREF*(1+R1/R2)+ IREF*R1 R2 VREF Figure 5. Test Circuit 5 for VKA>VREF VKA VIN IOFF Figure 6. Test Circuit 6 for IOFF Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 6 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Performance Characteristics 1.5 2.510 R1=10K,R2= ∞ VKA=VREF IKA=10mA Reference Current (µA) Reference Voltage (V) 2.505 IKA=10mA 2.500 2.495 1.0 0.5 2.490 2.485 -60 -40 -20 0 20 40 60 80 100 120 0.0 -60 140 -40 -20 0 o 60 80 100 120 140 Figure 8. Reference Current vs. Ambient Temperature 800 VKA=VREF VKA=VREF 0 0 TA=25 C TA=25 C 600 100 Cathode Current (µA) Cathode Current (mA) 40 Ambient Temperature ( C) Figure 7. Reference Voltage vs. Ambient Temperature 150 20 0 Ambient Temperature ( C) 50 0 400 200 0 -50 -200 -100 -2 -1 0 1 2 -1.0 3 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 Cathode Voltage (V) Cathode Voltage (V) Figure 9. Cathode Current vs. Cathode Voltage Figure 10. Cathode Current vs. Cathode Voltage Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 7 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Performance Characteristics (Continued) 1.8 VKA=36V 1.6 VREF=0 -0.9 VKA=3.5V to 36V -1.0 1.4 ∆VREF / ∆VKA (mV/V) Off-state Cathode Current (µA) 2.0 1.2 1.0 0.8 0.6 0.4 -1.1 -1.2 -1.3 0.2 -1.4 0.0 -40 -20 0 20 40 60 80 100 -40 120 -20 0 20 40 60 80 100 120 o o Ambient Temperature ( C) Ambient Temperature ( C) Figure 11. Off-state Cathode Current vs. Ambient Temperature Figure 12. Ratio of Delta Reference Voltage to the Ratio of Delta Cathode Voltage Output 70 0 TA=25 C 60 15K IKA=10mA Voltage Gain (dB) 50 I KA 242 10µF 40 30 20 8.2K 10 0 -10 1k 10k 100k GND 1M Small Signal Frequency (Hz) Figure 13. Small Signal Voltage Gain vs. Frequency Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 8 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Performance Characteristics (Continued) Output 1K IKA=10mA IKA Reference Impedance (Ω) o 10 TA=25 C 50 1 GND 0.1 1K 10K 100K 1,000K Frequency (Hz) Figure 14. Reference Impedance vs. Frequency 100 90 Cathode Current (mA) 80 VKA=VREF 70 VKA=10V 60 VKA=15V 150 R1 (10K) VKA= 5V IKA 50 Stable Stable 40 30 R2 20 10 0 0.001 0.01 0.1 1 10 Load Capacitance (µF) Figure 15. Stability Boundary Conditions vs. Load Capacitance Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 9 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Performance Characteristics (Continued) 5 Input and Output Voltage (V) Input Output 4 220 Pulse Generator f=100KHz 3 Output 2 50 1 GND 0 0 2 4 6 Time (µS) Figure 16. Pulse Response of Input and Output Voltage Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 10 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Application R3 V OUT VIN R1 VOUT=(1+R1/R2)*VREF V REF AN431 R2 Figure 17. Shunt Regulator VIN VOUT R1 R4 VOUT=(1+R2/R3)*VREF R2 VREF AN431 R3 Figure 18. High Current Shunt Regulator R2 V IN I OUT IOUT=VREF/R2 + IKA R1 AN431 Figure 19. Current Source or Current Limit Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 11 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Typical Application (Continued) VIN AZ1117 R1 8.2K VOUT Adjust 5V, 1A R2 250 AN431 R3 250 Figure 20. Precision 5V 1A Regulator R3 C1 R4 VOUT R2 680 R5 R1 U2 Q1 3 COMP C2 2 AN431 PWM Controller VFB 4 PS521 Figure 21. PWM Converter with Reference Mar. 2007 Rev. 1. 7 BCD Semiconductor Manufacturing Limited 12 Data Sheet ADJUSTABLE PRECISION SHUNT REGULATORS AN431 Mechanical Dimensions SOT-23 Mar. 2007 Rev. 1. 7 Unit: mm(inch) BCD Semiconductor Manufacturing Limited 13 http://www.bcdsemi.com IMPORTANT NOTICE BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifications herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or other rights nor the rights of others. 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