AS2431 Precision Adjustable Shunt Reference SEMICONDUCTOR Features Description • • • • • The AS2431 is a three-terminal adjustable shunt regulator providing a highly accurate bandgap reference. The adjustable shunt regulator is ideal for a wide variety of linear applications that can be implemented using external components to obtain adjustable currents and voltages. • Temperature-compensated: 15 ppm/°C Trimmed bandgap reference Internal amplifier with 100 mA capability Multiple temperature ranges Low frequency dynamic output impedance: < 450 mΩ Low output noise In the standard shunt configuration, the combination of low temperature coefficient (TC), sharp turn-on characteristics, low output impedance and programmable output voltage make this precision reference an excellent error amplifier. The AS2431 is a direct replacement for the AS431 in low voltage, low current applications. It is also available in the very small footprint SOT23. Pin Configuration – Top View TO-92 (LP) 8L SOIC (8D) CATHODE 1 8 REFERENCE ANODE 2 7 ANODE ANODE 3 6 ANODE N/C 4 5 N/C CATHODE ANODE REFERENCE SOT-89 (S) 3L SOT-23 (3VS) CATHODE CATHODE ANODE ANODE REFERENCE REFERENCE Ordering Information AS2431 A C 8D N Packaging Option: A = Ammo Pack B = Bulk T = Tube M = Tape and Reel (7" Reel Dia. SOT-23 Only) N = Tape and Reel (13" Reel Dia) Circuit Type: Precision Adjustable Shunt Regulator Bandgap Tolerance: A = ±0.25% C = ±0.5% D = ±1.0% E = ±2.0% Package Style: 8D = 8 Pin, Plastic SOIC LP = TO-92 S = SOT-89 3VS = 3 Pin, SOT-23 Temperature Range: A = 0°C to 70°C B = 0°C to 105°C C = –40°C to +85°C F = –55°C to +125°C www.ptcc.com.tw 17 AS2431 Precision Adjustable Shunt Reference Functional Block Diagram CATHODE (K) REFERENCE (R) + – 2.5 V ANODE (A) Absolute Maximum Ratings Parameter Symbol Rating Units VKA 18 V Cathode-Anode Reverse Breakdown Anode-Cathode Forward Current IAK 1 A Operating Cathode Current IKA 100 mA Reference Input Current IREF 1 mA Continuous Power Dissipation at 25°C PD TO-92 775 mW 8L SOIC 750 mW SOT-89 1000 mW 3L SOT-23 200 mW Junction Temperature TJ 150 °C Storage Temperature TSTG –65 to 150 °C TL 300 °C Lead Temp, Soldering 10 Seconds Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. Recommended Conditions Parameter Typical Thermal Resistances Symbol Rating Cathode Voltage VKA VREF to 18 V Cathode Current IK 10 mA www.ptcc.com.tw Unit θJA θJC Typical Derating TO-92 160°C/W 80°C/W 6.3 mW/°C SOIC 175°C/W 45°C/W 5.7 mW/°C SOT-89 110°C/W 8°C/W 9.1 mW/°C SOT-23/5L 575°C/W 150°C/W 1.7 mW/°C Package 18 AS2431 Precision Adjustable Shunt Reference mV % ppm Average Temperature Coefficient 0 0 0 ∆VREF (mV) • TC in mV/°C = ∆TA ∆VREF ∆VREF ∆T –10 5000 • TC in %/°C = 0.5 VREF at 25°C X 100 ∆TA ∆VREF –20 0 15 30 45 60 75 Temperature (°C) 90 105 • TC in ppm/°C = VREF at 25°C X 106 ∆TA 0.07 mV/°C 0.003%/°C 27 ppm/°C Test Circuits VIN IREF VKA = VREF IK VIN VKA IK R1 VIN VKA IK (OFF) IREF (VREF) R2 Figure 1a. Test Circuit 1 www.ptcc.com.tw Figure 1b. Test Circuit 2 20 Figure 1c. Test Circuit 3 Precision Adjustable Shunt Reference AS2431 Typical Performance Curves Low Current Operating Characteristics High Current Operating Characteristics 150 900 VKA = VREF Temperature Range: –55 to 125°C 800 700 100 IK – Cathode Current (mA) 600 IK – Cathode Current (µA) VKA = VREF Temperature Range: –55 to 125°C 125 500 400 125°C 300 25°C 200 –55°C 100 75 50 25 0 –25 –50 0 –75 –100 –200 –1.0 0 1.0 2.0 –100 –2 3.0 –1 0 VKA – Cathode Voltage (V) Figure 2 2 3 Figure 3 Off State Leakage Reference Voltage vs Ambient Temperature 100 3.53 VKA = 18 V VREF = 0 V 2.52 10 VREF – Reference Voltage (V) IZ off – Off State Cathode Current (nA) 1 VKA – Cathode Voltage (V) 1 0.1 VKA = VREF IK = 10 mA 2.51 2.50 VREF = 2.500 V at 25°C 2.49 2.48 2.47 2.46 0.01 –60 –30 0 30 60 90 2.45 –60 120 TA – Ambient Temperature (°C) 0 30 60 90 TA – Ambient Temperature (°C) Figure 4 www.ptcc.com.tw –30 Figure 5 21 120 AS2431 Precision Adjustable Shunt Reference Typical Performance Curves Reference Input Current Reference Voltage Line Regulation 0 3.0 R1 = 10 kΩ R2 = ∞ IK =10 mA –30°C ∆VREF – Change in Reference Voltage (mV) IREF – Reference Input Current (µA) 2.5 2.0 1.5 1.0 0.5 0 –60 –5 –10 25°C –15 75°C –20 –25 –30 0 30 60 90 0 120 3 6 9 12 15 18 VKA – Cathode Voltage (V) TA – Ambient Temperature (°C) Figure 6 Figure 7 Low Frequency Dynamic Output Impedance Noise Voltage 70 0.150 VKA = VREF IK = 10 mA TA = 25°C VKA = VREF IKA = 1 to 100 mA f ≤ 1 kHz 0.125 ZKA – Dynamic Impedance (Ω) 60 50 Noise Voltage nV/√Hz 125°C IK = 10 mA Temperature Range: –55 to 125°C 40 30 20 0.100 0.075 0.050 0.025 10 0.0 –60 0 10 100 1k 10 k 100 k f – Frequency (Hz) 0 30 60 TA – Free Air Temperature Figure 8 www.ptcc.com.tw –30 Figure 9 22 90 120 Precision Adjustable Shunt Reference AS2431 Typical Performance Curves Dynamic Output Impedance 100 ZKA – Dynamic Impedance (Ω) TA = 25°C IK = 1 to 100 mA 10 1.0 0.1 0.01 1k 10 k 100 k 1M 10 M f – Frequency (Hz) Figure 10 Small Signal Voltage Gain vs. Frequency 70 Temperature Range: –55 to 125°C AV – Small Signal Voltage Gain (dB) 60 OUT IK = 10 mA 50 9 µF 15 k IK 230 Ω 40 8.25 k 30 GND 20 10 0 1k 10 k 100 k 1M 10 M f – Frequency (Hz) Figure 11 www.ptcc.com.tw 23 AS2431 Precision Adjustable Shunt Reference Typical Performance Curves Pulse Response 6 Input INPUT MONITOR Input and Output Votages (V) 5 220 Ω OUT 4 3 Output 50 Ω fP = 100 kHz 2 1 GND 0 –1 0 1 2 3 4 5 6 7 8 t – Time (ms) 9 10 11 12 Figure 12 Stability Boundary Conditions 100 90 IK – Cathode Current (mA) 80 A: VKA = VREF B: VKA = 5 V at IK = 10 mA C: VKA = 10 V at IK = 10 mA D: VKA = 15 V at IK = 10 mA 150 Ω 70 IK C 60 50 CL 40 Stability Region 30 A 10 K 20 10 B TA = 25°C D 0 100 101 102 103 104 105 106 107 CL – Load Capacitance (pF) Figure 13 www.ptcc.com.tw 24