L432 ETC | Alldatasheet
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 11
Technical content
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 GENERAL DESCRIPTION The L432 is a three-terminal adjustable shunt regulator utilizing an a ccurate 1.24V band gap reference. The output voltage can be set to any value between 1.24V (V REF) to 18V with two external resistors as shown in the typical application circuit. The device exhibit a wide operating current range of 0.2 to 100 mA with a typical dynamic impedance of 0.25 Ω. Active output circuitry provides a very sharp turn-on characteristic, making the L432 excellent re- placements for low-voltage zener diodes in many applications, including on-board regulat- ion and adjustable power supplies. When used with an opto- coupler, the L432 is ideal voltage reference in isolated feedback circuits for 3.3V switching-mode power supplies. The L432 shunt regulator is available in two voltage tolerances (0.5% & 1.0%) and three package options (TO-92, SOT-23-3 and SO-8).
FEATURES
z Internal amplifier with 100 mA capability z Programmable output voltage to 18V z 0.25Ω typical output impedance z Pin to pin compatible with TLV431A, TS431, SC431L & AS432 z Trimmed bandgap design 0.5% & 1.0% with three package options z Low output noise
APPLICATIONS
z Linear regulator controller z Precision voltage reference z Switching power supplies z Battery operating equipment z Instrumentation z PCs, Computer disk drives SYMBOL & BLOCK DIAGRAM Anode (A) CathodReference Cathode (K) Anode (A) Reference (R)
1.24 Vref
FUNCTIONAL BLOCK DIAGRAMSYMBOL (R) (K)
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 ABSOLUTE MAXIMUM RATINGS PARAMETER VALUE Cathode-Anode Reverse Breakdown Voltage - VKA 20V Anode-Cathode Forward Current - IAK 1 A Operating Cathode Current - IKA 100 mA Reference Input Current - IREF 1 mA Storage Temperature Range - TSTG -65 to +150 °C Junction Temperature - TJ 150 °C Lead Temperature (Soldering, 10 Seconds) - TL 300 °C Continuous Power at 25 °C - PD TO-92 SOIC-8 SOT-23 700 mW 650 mW 200 mW RECOMMENDED CONDITIONS TYPICAL THERMAL RESISTANCES Parameter Rating Package θJA θJC Typ. De-rating Cathode Voltage (VKA) V REF to 18V TO-92 160 °C/W 80 °C/W 6.3 mW/°C Cathode Current (IK) 10 mA SOIC-8 175 °C/W 45 °C/W 5.7 mW/°C SOT-23 575 °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 TEST CONDITIONS MIN TYP MAX UNITS TEST CIRCUIT Line Regulation - ∆VREF VKA = VREF to 15V 28 50 mV 2 Load Regulation - ∆VREF IK = 1 to 100 mA 3.9 6 mV 1 Temperature Deviation - ∆VREF 0 < TJ < 105 °C 5 12 mV 1 Reference Input Current - IREF 2.3 6 µA 1 Reference Input Current Temperature Coefficient - ∆IREF 0 < TJ < 105 °C 0.14 0.6 µA 1 Minimum Cathode Current for Regulation - IK(MIN) 0.2 1 mA 1 Off State Leakage - IK(MIN) V REF = 0V, VKA = 15V 40 500 nA 3 Dynamic impedance VKA = Vref, f ≦ 1kHz IK = 0.1 mA to 100 mA 0.25 0.4 Ω 1
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 TEST CIRCUITS IN VV KA KI REFI VREF - TEST CIRCUIT 2 - >(VKA VREF) REFI )VKA V - TEST CIRCUIT 1 - KAV REF(V IN - TEST CIRCUIT 3 - KAVVIN K (OFF)I (OFF STATE CURRENT) IK Applications Information – Stability Selection of load capacitance when using L432 as a shunt regulator When the L432 is used as a shunt regulator, two options for selection of CL are recommended for optimal stability: 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 L432 exhibits instability with capacitances in the range of 1nF to 1uf (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 0.1uF 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 alter- natively a high capacitance (such as 10uF) will avoid this issue altogether. Since the user will probably wis h to have local decoupling at the load 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 de- coupling from causing the oscillation during the transient start-up phase. Note : if the L432 is located right at the load, so the load decoupling capacitor is directly across it, then this capacitor will have to be ≦ 100pF or ≧ 1uF.
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 Stability Boundary Condition For Shunt Regulation VS. Cathode Current and Load Capacitance Small-Signal Gain and Phase Shift VS. Frequency VS. Cathode Voltage Cathode Current CL R Test Circuit for Stability L432 2 3 Iz Cathode Current VS. Cathode Voltage 15K 232 GND 10uF OUT Iz 8.25K Test Circuit for Small Signal Gain and Phase L432 2 3
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 VS. Frequency Reference Impedance Ω Reference Voltage VS. Junction Temperature Ratio of Delta Reference Voltage to Delta Cathode Voltage ΔVz = 16V to Vref Δ Vref /Δ Vz (-m V/V) VS. Junction Temperature VS. Junction Temperature Reference Input Current
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 PIN CONFIGURATIONS VS. Junction Temperature rz (Ω Reference Impedance VS. Junction Temperature Off-State Cathode Current
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 DEVICE SELECTION GUIDE Device L432NB L432M3B L432VB L432M5B Package TO-92 SOT-23-3 SOIC-8 SOT-23-5 Marking L432NA 2M3A L432V 2M5A Tolerance 1% 1% 1% 1% APPLICATION CIRCUIT 10uF Cout Cin P01N02LM or P3055L L431 or L432 5V or 12V Vin Vout G D S A K R Niko Niko Vout = (1 + ) Vref
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 TO-92 MECHANICAL DATA mm mm B 4.318 5.334 I 0.356 0.533 C 12.7 15.5 J D 0.356 0.533 K E 1.143 1.27 1.397 L F 3.175 4.191 M G 0.762 1.270 N
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 SOT-23 (M3) MECHANICAL DATA mm mm A 0.95 H 0.10 0.15 0.25 B 2.60 2.80 3.00 I 0.37 C 1.40 1.60 1.80 J D 2.70 2.90 3.10 K E 1.00 1.10 1.30 L F 0.00 0.10 M G 0.35 0.4 0.5 N
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 SOIC-8 (D) MECHANICAL DATA mm mm A 4.8 5.0 H 0.4 1.27 B 3.8 4.0 I 0.18 0.25 C 5.8 6.2 J 0.22 D 0.35 0.48 K 0° 8° E 1.27 L F 1.65 M G 0.1 0.25 N
1.24V Low-Voltage Adjustable Precision Shunt Regulator NIKO-SEM L432 NOV-21-2001 SOT-23 (M5) MECHANICAL DATA mm mm A 1.0 1.10 1.30 e 1.90(TYP) A2 0.70 0.80 0.90 L 0.37 b 0.35 0.40 0.50 C 0.10 0.15 0.25 D 2.70 2.90 3.10 E 1.40 1.60 1.80