Bay Linear Inspire the Linear Power B431L 1.24V Adjustable Shunt Regulator Description Features The B431L is a three terminal adjustable shunt regulator with thermal stability of 50ppm/°C. The output voltage can be adjusted to any value from 1.24V (VREF) to 16V with two external resistors. These devices have a typical output impedance of 0.05Ω. Active output circuitry provides a very sharp turn-on characteristics and making the device excellent replacement for zener diodes in many applications. The B431L is an ideal voltage reference in an isolated feedback circuit for 3.0V switch mode power supplies The B431L shunt regulator is available with three voltage tolerances (0.5%, 1.0% and 2.0%) and three package options (SOT-23-3, TO-92, 8SOIC). This allows the designer the opportunity to select the optimum combination of cost and performance for their application. • • • • • Low voltage operation (down to 1.24V) Wide operating current……80µA to 100mA Trimmed bandgap design………….. ± 0.5% Low Dynamic Output Impedance…....0.05Ω Ω Wide temperature range…... -40°°C to +85°°C Available in ….….SOT-23-3, TO-92 , 8SOIC Pin-to-Pin Replacement …………….SC431L • • Applications • • • • • • Pin Connection Switching Power Supplies Adjustable Power Supplies Linear Regulators Battery Powered Equipment Monitors, TV, VCR Instrumentation Ordering Information Package TO-92 SO-8 SOT-23 0.5% B431LAZ B431LAM B431LAK3 Tolerance 1% B431LBZ B431LBM B431LBK3 2% B431LCZ B431LCM B431LCK3 SOT-23-3 (K3) TO-92 (Z) 1 2 Anode 3 BAY Ref Anode Bottom View Bay Linear, Inc Cathode Ref Cathode Top View 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Absolute Maximum Rating Parameter Cathode Voltage Continuous Cathode Current Reference Input Current Range Power Dissipation at TA - 25°C SOT-23-3 S0-8 TO-92 Thermal Resistance SOT-23-3 S0-8 TO-92 Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 seconds ESD Rating (Human Body Model) Symbol Maximum Units Vz Iz 20 100 3 V mA mA PD 0.37 0.75 0.95 W OJA 336 175 132 -40 to +150 -65 to +150 300 2 °C/W TJ TSTG TLEAD TESD °C °C °C kV Recommended Operating Conditions Cathode Voltage, Vz Cathode Current, Iz Min Max Symbol VREF 80µA 16 100 V mA Electrical Characteristics Unless specified: T٨ = 25°C. Values in bold apply over full operating ambient temperature. B431LA 0.5% Parameter Reference Voltage Symbol VREF Condition VZ = VREF1 IZ = 10mA(1) Min 1.234 Typ 1.240 1.222 VREF Temp Deviation Ratio of Change in VREF To Change in VZ Reference Input Current IREF Temperature Deviation Off-State Cathode Current Δ VREF ΔVZ IREF IREF(DEV) IZ (OFF) Min Operating Current Dynamic Impedance Bay Linear, Inc VDEV (1) VZ = VREF1, IZ = 10mA IA=full range IZ = 10mA,ΔVZ = 16V to VRef (2) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) Max 1.246 Units V 1.258 10 25 mV -2.7 -1.0 mV/V 0.15 0.5 µA 0.1 0.4 µA VREF = 0V, VZ =16V(3) VREF = 0V, VZ =16V(3) 0.125 0.150 0.135 0.150 IZ(MIN) VZ = VREF(1) 20 80 µA ZKA VKA=Vref, IK=100µA to 100mA, f≤1kHA 0.05 0.15 Ω µA 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Electrical Characteristics Unless specified: T٨ = 25°C. Values in bold apply over full operating ambient temperature. B431LB 1% Parameter Reference Voltage Symbol VREF Condition VZ = VREF1 IZ = 10mA(1) Min 1.228 Typ 1.240 1.215 VREF Temp Deviation Ratio of Change in VREF To Change in VZ Reference Input Current IREF Temperature Deviation Off-State Cathode Current VDEV Δ VREF ΔVZ Units V 1.265 10 25 mV -1.0 -2.7 mV/V 0.15 0.5 µA µA R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) VREF = 0V, VZ =16V(3) 0.1 0.4 0.125 0.150 VREF = 0V, VZ =16V(3) 0.135 0.150 IZ(MIN) VZ = VREF(1) 20 80 µA ZKA VKA=Vref, IK=100µA to 100mA, f≤1kHA 0.05 0.15 Ω IREF IREF(DEV) IZ (OFF) Min Operating Current Dynamic Impedance VZ = VREF1, IZ = 10mA(1) IA=full range IZ = 10mA,ΔVZ = 16V to VRef (2) Max 1.252 µA Electrical Characteristics Unless specified: T٨ = 25°C. Values in bold apply over full operating ambient temperature. B431LC 2% Parameter Reference Voltage Symbol VREF Condition VZ = VREF1 IZ = 10mA(1) Min 1.215 Typ 1.240 1.200 VREF Temp Deviation Ratio of Change in VREF To Change in VZ Reference Input Current IREF Temperature Deviation Off-State Cathode Current Δ VREF ΔVZ VZ = VREF1, IZ = 10mA IA=full range IZ = 10mA,ΔVZ = 16V to VRef (2) Units V 1.280 10 35 mV -1.0 -2.7 mV/V 0.15 0.5 µA µA R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) VREF = 0V, VZ =16V(3) 0.1 0.4 0.125 0.150 VREF = 0V, VZ =16V(3) 0.135 0.150 IZ(MIN) VZ = VREF(1) 20 80 µA ZKA VKA=Vref, IK=100µA to 100mA, f≤1kHA 0.05 0.15 Ω IREF IREF(DEV) IZ (OFF) Min Operating Current Dynamic Impedance Bay Linear, Inc VDEV (1) Max 1.265 µA 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Test Circuit: Small-Signal Gain & Phase 43 1 Test Circuit: Stability 431 L Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Application Notes: Stability: Selection of Load Capacitor Selection of load capacitor for when B431L is used as a shunt regulator, two options for selection of CL 1) No load capacitance across the device, decouple at the load 2) Large capacitance across the device, optional decoupling at the load. The reason for this is that B431L exhibits instability with capacitances in the range of 10nF to 1µF (approx.) at light cathode currents (up to 3mA typical). The device is less stable the lower the cathode voltage has been set for. Therefore while the device will be perfectly stable operating at a cathode current of 10mA with a 0.1µF capacitor across it, it will oscillate transiently during start-up as the cathode current passes through the instability region. Selecting a very low (or preferably, no) capacitance, or alternatively a high capacitance such as 10µF will avoid this issue altogether. Since the user anyway, the most cost effective method is to use no capacitance at all directly across the device. PCB trace/via resistance and inductance prevent the local load decoupling from causing the oscillation during the transient start-up phase. Note: if the B431L is located right at the load, so the load decoupling capacitor is directly across it, then this capacitor will have to be ≤1nF or ≥ 10µF B431 Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L Test Circuits: Application Circuit: +3.3V 0.1µF 470µF PHD 3055E +12V 500Ω 2.7V 140Ω 0.1µF 0.1µF 0.1µF B431L 120Ω INTEL I 740 1000µF *If the output voltage has noise, then please add a 0.1µF in between drain and gate of power MOSFET to reduce the noise. Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com B431L SOT-23 0.015 - 0.018 (0.381 - 0.457) 0.047 - 0.055 0.083 - 0.098 (1.194 - 1.397) (2.108 - 2.489) 0.035 - 0.040 (0.889 - 1.016) 0.020 - 0.024 (0.508 - 0.610) 0.070 - 0.080 (1.778 - 2.032) 0.110 - 0.120 (2.794 - 3.048) 0.001 - 0.004 (0.025 - 0.102) 0.003 - 0.005 (0.076 - 0.127) 0.030 - 0.041 (0.762 - 1.041) 0.018 - 0.024 (0.457 - 0.610) Advance Information- These data sheets contain descriptions of products that are in development. The specifications are based on the engineering calculations, computer simulations and/ or initial prototype evaluation. Preliminary Information- These data sheets contain minimum and maximum specifications that are based on the initial device characterizations. These limits are subject to change upon the completion of the full characterization over the specified temperature and supply voltage ranges. The application circuit examples are only to explain the representative applications of the devices and are not intended to guarantee any circuit design or permit any industrial property right to other rights to execute. Bay Linear takes no responsibility for any problems related to any industrial property right resulting from the use of the contents shown in the data book. Typical parameters can and do vary in different applications. Customer’s technical experts must validate all operating parameters including “ Typical” for each customer application. LIFE SUPPORT AND NUCLEAR POLICY Bay Linear products are not authorized for and should not be used within life support systems which are intended for surgical implants into the body to support or sustain life, in aircraft, space equipment, submarine, or nuclear facility applications without the specific written consent of Bay Linear President. Bay Linear, Inc 2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com