AS1431 Precision Adjustable Shunt Reference SEMICONDUCTOR Features Description ¥ ¥ ¥ ¥ The AS1431 is a three-terminal adjustable shunt regulator providing a highly accurate 0.4% 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. 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 a perfect zener diode replacement. The AS1431 is characterized to operate over the full automotive temperature range of Ð55 to 125¡C and is now available in the SOT-23 (5L) package. ¥ ¥ ¥ Temperature-compensated: 30 ppm/¡C Trimmed 0.4% bandgap reference Internal amplifier with 150 mA capability Temperature range: Extended to Ð55 to125¡C Low frequency dynamic output impedance: < 150 m½ Low output noise Robust ESD protection Pin Configuration Ñ Top view TO-92 (LP) SOIC (D) CATHODE 1 8 REFERENCE ANODE 2 7 ANODE ANODE 3 6 ANODE N/C 4 5 N/C CATHODE ANODE REFERENCE SOT-89 (S) SOT-23/5L (DBV) N/C CATHODE REFERENCE ANODE N/C CATHODE ANODE REFERENCE Ordering Information AS1431 D R4 D 7 Circuit Type: Precision Adjustable Shunt Regulator Packaging Option: A = Ammo Pack B = Bulk T = Tube 7 = Tape and Reel (7" Reel Dia) 13 = Tape and Reel (13" Reel Dia) Temperature Range: D = –55°C to +125°C Bandgap Tolerance: R4 = ±0.4% ASTEC Semiconductor Package Style: D = SOIC DBV = SOT-23/5L LP = TO-92 S = SOT-89 1 AS1431 Precision Adjustable Shunt Reference Functional Block Diagram CATHODE (K) REFERENCE (R) + Ð 2.5 V ANODE (A) Absolute Maximum Ratings Parameter Symbol Rating Units Cathode-Anode Reverse Breakdown VKA 37 V Anode-Cathode Forward Current IAK 1 A Operating Cathode Current IKA 250 mA Reference Input Current IREF 10 mA Continuous Power Dissipation at 25¡C PD 775 mW 8L SOIC 750 mW SOT-89 1000 mW SOT-23/5L 200 mW TO-92 Junction Temperature TJ 150 ¡C Storage Temperature TSTG Ð65 to 150 ¡C TL 300 ¡C Lead Temperature 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 Unit Cathode Voltage VKA VREF to 20 V Cathode Current IK 10 mA ASTEC Semiconductor 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 2 Precision Adjustable Shunt Reference AS1431 Electrical Characteristics Electrical Characteristics are guaranteed over full junction temperature range (Ð55 to 125¡C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. The conditions are: VKA = VREF and IK = 10 mA unless otherwise stated. Parameter Symbol Reference Voltage VREF ÆVREF with Temp* TC Ratio of Change in VREF to Cathode Voltage ÆVREF Test Condition Min. Typ. Max. Unit Circuit TA = 25¡C 2.490 2.500 2.510 V 1 Over temp. 2.470 2.530 V 1 0.16 mV/¡C 1 mV/V 2 0.06 ÆVK = 3 V to 36 V Ð2 Ð1.1 Reference Input Current IREF R1 = 10 k ½; R2 = ° 0.7 1.9 µA 2 IREF Temp Deviation ÆIREF Over temp. 0.4 1.2 µA 2 Min IK for Regulation IK(min) 0.4 1 mA 1 Off State Leakage IK(off) VREF = 0 V, VKA = 36 V 0.04 500 nA 3 Dynamic Output Impedance ZKA f ² 1 kHz IK = 1 to 100 mA 0.15 0.2 ½ 1 *Calculating Average Temperature Coefficient (TC) 0 mV % ppm Average Temperature Coefficient 0 0 ∆VREF (mV) • TC in mV/°C = ∆TA ∆VREF –10 5000 ∆VREF ∆T 0.5 • TC in %/°C = –20 VREF at 25°C X 100 ∆TA ∆VREF –55 –25 0 25 50 75 Temperature (°C) 100 • TC in ppm/°C = 0.06 mV/°C 0.002%/°C 24 ppm/°C ASTEC Semiconductor 125 3 VREF at 25°C ∆TA X 106 AS1431 Precision Adjustable Shunt Reference Test Circuits VIN IREF VKA = VREF IK VIN VKA IK R1 VIN VKA IK (OFF) IREF (VREF) R2 Figure 1a. Test Circuit 1 ASTEC Semiconductor Figure 1b. Test Circuit 2 4 Figure 1c. Test Circuit 3 Precision Adjustable Shunt Reference AS1431 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 Figure 2 2 3 Figure 3 Off State Leakage Reference Voltage vs Ambient Temperature 100 2.53 VKA = 36 V VREF = 0 V 2.52 10 VREF – Reference Voltage (V) IZ off – Off State Cathode Current (nA) 1 VKA – Cathode Voltage (V) 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 TA – Ambient Temperature (°C) Figure 4 ASTEC Semiconductor –30 Figure 5 5 90 120 AS1431 Precision Adjustable Shunt Reference Typical Performance Curves Reference Input Current Reference Voltage Line Regulation 3.0 0 IREF – Reference Input Current (µA) VREF – Change in Reference Voltage (mV) R1 = 10 kΩ R2 = ∞ IK =10 mA 2.5 2.0 1.5 1.0 0.5 0 –60 –30 0 30 60 90 –10 –55°C 0°C –20 25°C 75°C –30 125°C –40 IK = 10 mA Temperature Range: –55 to 125°C –50 120 0 3 6 TA – Ambient Temperature (°C) Figure 6 24 27 30 Figure 7 Noise Voltage Low Frequency Dynamic Output Impedance 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 9 12 15 18 21 VKA – Cathode Voltage (V) 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 ASTEC Semiconductor –30 Figure 9 6 90 120 Precision Adjustable Shunt Reference AS1431 Typical Performance Curves Dynamic Output Impedance 100 TA = 25°C IK = 1 to 100 mA ZKA – Dynamic Impedance (Ω) 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 ASTEC Semiconductor 7 AS1431 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 –0 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 B 10 0 100 TA = 25°C 101 D 102 103 104 105 CL – Load Capacitance (pF) 106 107 Figure 13 ASTEC Semiconductor 8