AS1431 Precision Adjustable Shunt Regulator FEATURES APPLICATIONS • • • • • • • • • • • • • • Voltage Tolerance ................................................ 0.4% Wide Operating Current .....................1mA to 150mA Extended Temperature Range ........... -55°°C to 125°°C Low Temperature Coefficient ........................30 ppm/°C Improved Replacement in Performance for LT1431 Offered In Small Low Power SOT-89 Package Low Output Noise Battery Operating Equipment Adjustable Supplies Switching Power Supplies Error Amplifiers Single Supply Amplifiers Monitors / VCR / TV Personal Computers PRODUCT DESCRIPTION The AS1431 is a 3-terminal Adjustable Shunt Voltage Regulator providing a highly accurate 0.4% bandgap reference. AS1431 acts as an open-loop error amplifier with a 2.5V temperature compensation reference. The AS1431 thermal stability, wide operating current (150mA) and temperature range (125°C) makes it suitable for all varieties of applications that are looking for a low cost solution with high performance. AS1431 tolerance of 0.4% 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. In the standard shunt configuration, the combination of low temperature coefficient (T.C.), sharp turn-on characteristics, low output impedance and programmable output voltage that makes this precision reference an excellent error amplifier. The AS1431 is a direct improved replacement for the AS431 and TL431 in low voltage, low current applications. PIN CONFIGURATIONS Standard Pinout 8-Pin Surface Mount (S) CATHODE 1 8 REF ANODE 2 7 ANODE ANODE 3 6 ANODE N/C 4 5 N/C AS1431 Top View SOT-23-5 (M5) REF ANODE 5 4 SOT-89 (M1) 1 N/C 2 N/C 2 3 AS1431 AS1431 1 TO-92 (N) 3 CATHODE Top View REF 1 2 ANODE 3 CATHODE Front View REF CATHODE ANODE Bottom View Rev. 10/5/00 AS1431 ORDERING INFORMATION Part Number AS1431N AS143S1/S2 AS1431M1 AS1431M5 Temperature Range -55°C to 125°C -55°C to 125°C -55°C to 125°C -55°C to 125°C CATHODE (K) Package Type TO-92 SOIC SOT-89 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 1 250 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 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 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 AS1431 ELECTRICAL CHARACTERISTICS are guaranteed over full junction temperature range (-55°C to 125°C). Ambient temperature must be derated based on power dissipation and package thermal characteristics. The conditions are: VKA = VREF and IK = 10mA, unless otherwise specified. Parameter Symbol Test Conditions Test Circuit Min Typ Max Units Reference Voltage VREF 1 2.490 2.500 2.510 V TA = 25°C Over Temp. 1 2.465 2.535 V VREF with Temp* TC 1 0.06 0.16 mV/° C Ratio of Change in VREF VREF VK = 3V to 36V 2 -2 -1.1 mV/V to Cathode Voltage Reference Input Current IREF RI = 10 k; R2 = 2 0.7 1.9 µA IREF Temp Deviation IREF Over Temp. 2 0.4 1.2 µA Min IK for Regulation IK (min) 1 0.4 1 mA Off State Leakage IK (off) VREF = 0V, VKA = 3 0.04 250 nA 36V Dynamic Output ZKA f < 1 kHz IK 1 to 1 0.15 0.2 Ω Impedance 100mA mV % 0 ∆VREF ∆Τ -10 5000 TC in %/°C = 0.5 -20 ∆VREF (mV) TC in mV/°C = -55 -25 0 25 50 75 ∆TA TC in ppm/°C = 100 125 ∆VREF VREF at 25°C ) 0 ) 0 ppm Calculating Average Temperature Coefficient (TC) ) x 100 ∆TA ∆VREF VREF at 25°C ) x 106 ∆TA Temperature (°C) 0.06 mV/°C 0.002 %/°C 24 ppm/°C TEST CIRCUITS VIN VKA = VREF IREF IK VIN VKA R1 (VREF) 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 AS1431 TYPICAL PERFORMANCE CURVES High Current Operating Characteristics Low Current Operating Characteristics 900 150 VKA = VREF Temperature Range: - 55 to 125 °C 800 700 IK - Cathode Current (mA) 100 600 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 -100 -200 -1.0 0 1.0 2.0 -2 3.0 -1 VKA - Cathode Voltage (V) Figure 2 1 2 3 Figure 3 Off State Leakage Reference Voltage vs. Ambient Temperature 2.53 100 VKA = 18V VREF = 0V VKA = VREF IK = 10 mA 2.52 10 VREF - Reference Voltage (V) IZ off - Off State Cathode Current (nA) 0 VKA - Cathode Voltage (V) 1 0.1 2.51 2.50 VREF = 2.500 V at 25 °C 2.49 2.48 2.47 2.46 0.01 2.45 -60 -30 0 30 60 TA - Ambient Temperature ( °C) Figure 4 90 120 -60 -30 0 30 60 90 120 TA - Ambient Temperature ( °C) Figure 5 Rev. 10/5/00 AS1431 TYPICAL PERFORMANCE CURVES Reference Input Current Reference Voltage Line Regulation 3.0 0 VREF - Change in Reference Voltage (mV) IREF - Reference Input Currentµ(A) R1 = 10 kΩ R2 = ∞ IK = 10 mA 2.5 2.0 1.5 1.0 0.5 -10 -55 °C 0 °C -20 25 °C 75 °C -30 125 °C -40 -50 0 -60 -30 0 30 60 90 120 0 3 6 TA - Ambient Temperature ( °C) Figure 6 9 12 15 18 21 24 27 30 VKA - Cathode Voltage (V) Figure 7 Noise Voltage Low Frequency Dynamic Output Impedance 70 0.150 VKA = VREF IKA = 1 to 100 mA f < 1 kHz 60 () ZKA - Dynamic Impedance Ω Noise Voltage nV/vHz 0.125 50 40 30 20 0.100 0.075 0.050 0.025 10 VKA = VREF IK = 10 mA TA = 25 C 0.0 0 10 100 1k f - Frequency (Hz) Figure 8 10 k 100 k -60 -30 0 30 60 90 120 TA - Free Air Temperature Figure 9 Rev. 10/5/00 AS1431 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 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 f - Frequency (Hz) 1M 10 M Figure 11 Rev. 10/5/00 AS1431 TYPICAL PERFORMANCE CURVES Pulse Response 6 INPUT 5 Input and Output Voltages (V) 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 IK - Cathode Current (mA) 80 70 C 150 Ω 60 IK 50 40 STABILITY REGION CL 30 10 k A 20 B T A = 25 °C 10 D 0 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 CL - Load Capacitance (pF) Figure 13 Rev. 10/5/00