AS431 Precision Adjustable Shunt Regulator FEATURES APPLICATIONS • Trimmed Bandgap to 0.5% • Wide Operating Current..........................1mA to 150mA • Extended Temperature Range....................0°°C to 105°°C • Low Temperature Coefficient ............................30 ppm/°C • Offered in TO-92, SOIC, SOT-89, SOT-23-5 • Improved Replacement in Performance for TL431 • Low Cost Solution • Battery Operating Equipments • Adjustable Supplies • Switching Power Supplies • Error Amplifiers • Single Supply Amplifier • Monitors / VCR / TV • Personal Computers PRODUCT DESCRIPTION The AS431 is a 3-terminal adjustable shunt voltage regulator providing a highly accurate 0.5% bandgap reference. AS431 acts as an open-loop error amplifier with a 2.5V temperature compensation reference. The AS431 thermal stability, wide operating current (150mA) and temperature range (0°C to 105°C) makes it suitable for all variety of application that are looking for a low cost solution with high performance. AS431 tolerance of 0.5% is proven to be sufficient to overcome all of the other errors in the system to virtually eliminate the need for trimming in the power supply manufactures assembly line and contribute a significant Cost Savings. The output voltage may be adjusted to any value between VREF and 36 volts with two external resistors. The AS431 is operating an extended temperature range of 0°C to 105°C. The AS431 is available in TO-92, SO-8, SOT-89, and SOT-23-5 packages. PIN CONFIGURATIONS 8-Pin Surface Mount (S) CATHODE 1 ANODE 2 ANODE 3 N/C 4 AS431 8 REF 7 ANODE 6 ANODE 5 N/C SOT-23-5 (M5) REF ANODE 5 4 SOT-89 (M1) 1 N/C 2 N/C 2 3 AS431 AS431 1 TO-92 (N) 3 CATHODE Top View 1 REF 2 3 ANODE Top View CATHODE REF ANODE CATHODE Bottom View Top View Rev. 10/5/00 AS431 ORDERING INFORMATION Part Number AS431N AS431M1 AS431S AS431M5 Temperature Range 0°C to 105°C 0°C to 105°C 0°C to 105°C 0°C to 105°C CATHODE (K) Package Type TO-92 SOT-89 SO-8 SOT-23-5 REFERENCE (R) + 2.5V ANODE (A) ABSOLUTE MAXIMUM RATINGS PARAMETER Cathode-Anode Reverse Breakdown Anode-Cathode Forward Current Operating Cathode Current Reference Input Current Continuous Power Dissipation at 25° C TO-92 SOT-23 8L SOIC SOT-89 Junction Temperature Storage Temperature Lead Temperature (Soldering 10 sec.) SYMBOL VKA IAK IKA IREF PD TJ TSTG TL RATING 37 1 150 10 UNITS V A mA mA 775 200 750 1000 150 - 65 to 150 300 mW mW mW mW °C °C °C Stresses greater than those listed under ABSULUTE 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 Cathode Voltage Cathode Current SYMBOL VKA IK RATING VREF to 20 10 TYPICAL THERMAL RESISTANCES UNIT V mA PACKAGE TO-92 SOT-23 SOIC SOT-89 0JA 160 °C/W 575 °C/W 175 °C/W 110 °C/W 0JC 80 °C/W 150 °C/W 45 °C/W 8 °C/W TYPICAL DERATING 6.3 mW/°C 1.7 mW/°C 5.7 mW/°C 9.1 mW/°C Rev. 10/5/00 AS431 ELECTRICAL CHARACTERISTICS at 25°C IK @ 10mA VK = VREF, unless otherwise specified. Parameter Symbol Reference Voltage Test Conditions VREF ∆VREF with Temp.∗ Ratio of Change in VREF to Cathode Voltage Reference Input Current IREF Temp Deviation Min IK for Regulation Off State Leakage TC ∆ VREF ∆VK IREF ∆IREF IK(MIN) IK(OFF) Dynamic Output Impedance ZKA Test Circuit 1 1 1 TA = 25°C Over Temp. VREF to 10V 10V to 36V Min 2.490 2.469 2 2 2 1 Over Temp. VREF = 0V, VKA = 36V -2.7 -2 3 1 AS431 Typ 2.503 Unit Max 2.515 2.536 0.20 0.07 -1.0 -0.4 0.7 0.4 0.4 0.04 0.15 V V mV/°C mV/V 0.3 4 1.2 1 250 µA µA mA nA 0.5 Ω TC = Test Circuit mV % 0 ∆VREF ∆Τ -10 5000 TC in %/°C = 0.5 -20 ∆VREF (mV) TC in mV/°C = -55 -25 0 25 50 75 ∆T A TC in ppm/°C = 100 125 ∆VREF VREF at 25°C ) 0 ) 0 ppm Calculating Average Temperature Coefficient (TC) ) x 100 ∆T A ∆VREF VREF at 25°C ) x 10 6 ∆T A Temperature (°C) 0.06 mV/°C 0.002 %/°C 24 ppm/°C TEST CIRCUITS VIN VKA = VREF IREF IK VIN R1 (VREF) VKA IK VIN VKA IK (OFF) IREF R2 Figure 1a. Test Circuit 1 Figure 1b. Test Circuit 2 Figure 1c. Test Circuit 3 Rev. 10/5/00 AS431 TYPICAL PERFORMANCE CURVES High Current Operating Characteristics Low Current Operating Characteristics 150 900 VKA = VREF Temperature Range: -0°C to 125 °C 800 700 100 600 500 400 105 °C 300 25 °C 200 75 IK - Cathode Current (mA) µA) IK - Cathode Current (µ VKA= V REF Temperature Range: - 0°C to 105 °C 125 50 25 0 -25 -0 °C 100 -50 0 -75 -100 -100 -200 -1.0 0 1.0 2.0 -2 3.0 -1 0 VKA - Cathode Voltage (V) 2 3 Figure 3 Figure 2 Off State Leakage Reference Voltage vs. Ambient Temperature 100 2.53 VKA = 36V VREF = 0V V KA= V REF IK = 10 mA 2.52 VREF - Reference Voltage (V) IZ off - Off State Cathode Current (nA) 1 VKA - Cathode Voltage (V) 10 1 0.1 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 TA - Ambient Temperature ( °C) Figure 4 90 120 2.45 -60 -30 0 30 60 90 120 TA - Ambient Temperature ( °C) Figure 5 Rev. 10/5/00 AS431 TYPICAL PERFORMANCE CURVES Reference Voltage Line Regulation Reference Input Current 3.0 0 R1 = 10 k Ω R2 = ∞ IK = 10 mA 2.5 VKA - Cathode Voltage (V) IREF - Reference Input Current (µA) -10 2.0 1.5 1.0 0 °C -20 25 °C 75 °C -30 105 °C -40 0.5 -50 0 -60 -30 0 30 60 90 120 0 3 6 TA - Ambient Temperature ( °C) 9 12 15 18 21 24 27 30 VKA - Cathode Voltage (V) Figure 6 Figure 7 Low Frequency Dynamic Output Impedance Noise Voltage 0.150 70 VKA = VREF IKA = 1 to 100 mA f < 1 kHz 60 0.125 ZKA - Dynamic Impedance ( Ω ) √Hz Noise Voltage nV/√ 50 40 30 20 0.100 0.075 0.050 0.025 10 V KA = V REF IK = 10 mA TA = 25°C 0 0.0 -60 10 100 1k 10 k -30 0 30 60 90 120 100 k f - Frequency (Hz) TA - Free Air Temperature Figure 8 Figure 9 Rev. 10/5/00 AS431 TYPICAL PERFORMANCE CURVES Dynamic Output Impedance 100 ZKA - Dynamic Impedance TA = 25 °C IK = 1 to 100 mA 10 1.0 0.1 0.01 1k 10 k 100 k 10 M 1M f - Frequency (Hz) Figure 10 Small Signal Voltage Gain vs. Frequency 70 AV - Small Signal Voltage Gain (dB) Temperature Range: -0°C to 105 °C 60 IK = 10 mA 50 OUT 40 15 k IK 230 Ω 9 µF 30 8.25 k 20 GND 10 0 1k 10 k 100 k 1M 10 M f - Frequency (Hz) Figure 11 Rev. 10/5/00 AS431 TYPICAL PERFORMANCE CURVES Pulse Response 6 INPUT Input and Output Voltages (V) 5 INPUT MONITOR 220 Ω OUT 4 3 OUTPUT 50 Ω 2 fP = 100 kHz 1 GND 0 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 t - Time ( µs) Figure 12 Stability Boundary Conditions 100 A: B: C: D: 90 V KA = V REF V KA = 5V at I K = 10 mA V KA = 10V at I K = 10 mA V KA = 15V at I K = 10 mA 80 IK - Cathode Current (mA) 70 C 150 Ω 60 IK 50 40 STABILITY REGION CL 30 10 k A 20 B TA = 25 °C 10 D 0 100 101 102 103 104 105 C L - Load Capacitance (pF) 106 107 Figure 13 Rev. 10/5/00