L431

NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator FEATURES L431 GENERAL DESCRIPTION The L431 is a three-terminal adjustable shunt regulator utilizing an accurate 2.5V band-gap reference. The output voltage can be set to any value between 2.5V (VREF) to 29V with two external resistors as shown in the typical application circuit. The device exhibit a wide operating current range of 0.4 to 100 mA with a typical dynamic impedance of 0.25Ω. The characteristics of these reference make it excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op amp circuitry. The 2.5V volt reference makes it convenient to obtain a stable reference from 5.0V logic supplies. The L431 shunt regulator is available in three voltage tolerances (0.5%, 1.0% and 2%) and three package options (TO-92, SOT-23-3, SOT-23-5 and SOIC-8). Internal amplifier with 70 mA capability Programmable output voltage to 29V 0.25Ωtypical output impedance Pin to pin compatible with TL431, LM431 , SC431 & AS431 Trimmed band-gap design 0.5%, 1.0% and 2% with three package options Low cost solution APPLICATIONS Linear regulator controller Precision voltage reference Switching power supplies Battery operating equipment Instrumentation PCs, Computer disk drives SYMBOL & BLOCK DIAGRAM Cathode (K) Reference (R) + Cathod (K) Reference (R) 2.5 Vref Anode (A) Anode (A) SYMBOL FUNCTIONAL BLOCK DIAGRAM 1 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 ABSOLUTE MAXIMUM RATINGS PARAMETER Cathode-Anode Reverse Breakdown Voltage - VKA Anode-Cathode Forward Current - IAK Reference Input Current - IREF Storage Temperature Range - TSTG Junction Temperature - TJ Lead Temperature (Soldering, 10 Seconds) - TL Continuous Power at 25 °C - PD TO-92 SOIC-8 SOT-23 VALUE 30V 70 mA 10 mA -65 to +150 °C 150 °C 300 °C 700 mW 650 mW 200 mW RECOMMENDED CONDITIONS Parameter Cathode Voltage (VKA) Cathode Current (IK) Rating VREF to 29V 10 mA TYPICAL THERMAL RESISTANCES Package TO-92 SOIC-8 SOT-23 Typ. Derating θJA θJC 160 °C/W 80 °C/W 6.3 mW/°C 175 °C/W 45 °C/W 5.7 mW/°C 575 °C/W 150 °C/W 1.7 mW/°C ELECTRICAL SPECIFICATIONS (Ambient temperature must be derated base on power dissipation and package thermal characteristics. The conditions are: VKA = VREF and IK = 10 mA unless otherwise stated) PARAMETER Reference Voltage ∆VREF with Temp. Ration of Change in VREF to Cathode Voltage Reference Input Current IREF Temp. Deviation Min. IK for Regulation Off State Leakage Dynamic Output Impedance TEST CONDITIONS TA = 25 °C, L431 (0.5%) TA = 25 °C, L431 (1%) TA = 25 °C, L431 (2%) VREF to 10V 10V to 30V Over Temp. VREF = 0V, VKA = 30V f ≤ 1KHz, IK = 1 to 70 mA MIN 2.482 2.470 2.445 -2.7 -2.0 TEST TYP MAX UNITS CIRCUIT 2.495 2.507 1 2.495 2.520 V 2.495 2.550 0.07 0.2 mV/°C 1 -1.0 mV/V 2 -0.4 0.3 µA 0.7 4 2 µA 0.4 1.2 2 mA 0.4 1 1 nA 0.04 250 3 0.25 0.5 1 Ω 2 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 TEST CIRCUITS VIN VKA VIN VKA VIN VKA I REF IK R1 V REF R2 I REF IK I K (OFF) - TEST CIRCUIT 1 (VKA = VREF ) - TEST CIRCUIT 2 (VKA > VREF ) - TEST CIRCUIT 3 (OFF STATE CURRENT) Stability Boundary Condition For Shunt Regulation VS. Cathode Current and Load Capacitance Test Circuit for Vka > Vref 150 Ik 3 R1 1 L431 CL 1 VBATT 2 2 R2 10K 0 1 2 3 4 5 6 Test Circuit for Vka = Vref The areas under the curves represent conditions that may 1 150 3 1 L431 2 2 cause the device to oscillate. For curves B, C and D, R1 and VBATT were adjusted to establish the initial VKA and IKA conditions with CL = 0. VBATT and CL then were adjusted to determine the ranges of stability. Ik CL 3 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 Small-Signal Gain and Phase Shift VS. Frequency Test Circuit for Small Signal Gain and Phase OUT 3 15K 1 1 10uF 8.25K Ik 1 L431 2 2 232 2 GND Cathode Current VS. Cathode Voltage Cathode Current VS. Cathode Voltage Reference Impedance VS. Junction Temperature Ratio of Delta Reference Voltage to Delta Cathode Voltage VS. Junction Temperature ΔVref /ΔVz (-mV/V) ΔVz = 3V to 30V rz (Ω) 4 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 Off-State Cathode Current VS. Junction Temperature Reference Input Current VS. Junction Temperature ∞ Reference Impedance VS. Frequency Reference Voltage VS. Junction Temperature Ω 5 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 PIN CONFIGURATION DEVICE SELECTION GUIDE Device Package Marking Tolerance L431NA TO-92 L431N 0.5% L431M3A SOT-23-3 1M3 0.5% L431VA SOIC-8 L431V 0.5% L431M5A SOT-23-5 1M5A 0.5% 6 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 APPLICATION CIRCUIT P01N02LM or P3055L Niko Vin Cin 5V or 12V 1K + +D S G R1 + Vout K A R L431 or L432 Niko Cout 10uF R2 Vout = (1 + R1 R2 ) Vref 7 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 TO-92 MECHANICAL DATA mm Min. 4.445 4.318 12.7 0.356 1.143 3.175 0.762 1.27 Typ. Max. 5.207 5.334 15.5 0.533 1.397 4.191 1.270 mm Min. 2.413 0.356 Typ. 2.540 Max. 2.667 0.533 Dimension A B C D E F G Dimension H I J K L M N 8 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 SOT-23 (M3) MECHANICAL DATA mm Min. 2.60 1.40 2.70 1.00 0.00 0.35 0.4 Typ. 0.95 2.80 1.60 2.90 1.10 3.00 1.80 3.10 1.30 0.10 0.5 Max. mm Min. 0.10 0.37 Typ. 0.15 Max. 0.25 Dimension A B C D E F G Dimension H I J K L M N 9 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator L431 SOIC-8 (D) MECHANICAL DATA mm Min. 4.8 3.8 5.8 0.35 1.27 1.65 0.1 0.25 Typ. Max. 5.0 4.0 6.2 0.48 mm Min. 0.4 0.18 0.22 0° 8° Typ. Max. 1.27 0.25 Dimension A B C D E F G Dimension H I J K L M N 10 JAN-08-Y02 NIKO-SEM 2.5V Low-Voltage Adjustable Precision Shunt Regulator SOT-23 (M5) MECHANICAL DATA mm mm Min. 2.60 0.37 Typ. 1.90(TYP) 2.80 L431 Dimension A A1 A2 b C D E Min. 1.0 0.00 0.70 0.35 0.10 2.70 1.40 Typ. 1.10 0.80 0.40 0.15 2.90 1.60 Max. 1.30 0.10 0.90 0.50 0.25 3.10 1.80 Dimension e H L Max. 3.00 11 JAN-08-Y02