SC431L Low Voltage Adjustable Shunt Regulator POWER MANAGEMENT Description Features The SC431L is a three terminal adjustable shunt regulator with thermal stability guaranteed over temperature. The output voltage can be adjusted to any value from 1.24V (V REF ) to 20V with two external resistors. The SC431L has a typical dynamic output impedance of 0.05Ω. Active output circuitry provides a very sharp turn on characteristic, making the SC431L an excellent replacement for zener diodes. The SC431L shunt regulator is available with four voltage tolerances (0.25%, 0.5%, 1.0% and 2.0%), two operating temperature ranges (commercial and industrial) and two package options (SOT-23-3 and SOT-235). This allows the designer the opportunity to select the optimum combination of cost and performance for their application. Applications Low voltage operation (down to 1.24V) Wide operating current range 100µA to 100mA Low dynamic output impedance 0.05 Ω typ. Trimmed bandgap design ± 0.25% Upgrade for TLV431A SOT-23-3 and SOT-23-5 packages. Also available in Lead-free package, fully WEEE and RoHS compliant Linear Regulators Adjustable Supplies Switching Power Supplies Battery Operated Computers Instrumentation Computer Disk Drives Typical Application Circuit(1)(2) Notes: 1) Set VOUT according to the following equation: R1 VOUT = VREF 1 + + IREF R1 R 2 2) Choose the value for R as follows: • The maximum limit for R should be such that the cathode current, I Z , is greater than the minimum operating current (100µA) at VIN(MIN). • The minimum limit for R should be such that IZ does not exceed 100mA under all load conditions, and the instantaneous turn-on value for I Z does not exceed 150mA. Both of the following conditions must be met: R min ≥ R min ≥ V IN (max) 150 mA (to limit instantaneous turn-on IZ) V IN (max) − V OUT I OUT (min) + 100 mA (to limit IZ under normal operating conditions) Revision: October 4, 2007 1 www.semtech.com SC431L POWER MANAGEMENT Absolute Maximum Ratings Parameter Symbol Maximum Units Cathode Voltage VZ 20 V Continous Cathode Current IZ 100 mA Reference Input Current IREF 3 mA Power Dissipation at TA = 25°C SOT-23-3 SOT-23-5 PD 0.37 0.49 W Thermal Resistance SOT-23-3 SOT-23-5 θJ A 336 256 °C/W Operating Ambient Temperature Range S C 431LC S C 431LI TA 0 to +70 -40 to +85 °C Operating Junction Temperature Range S C 431LC S C 431LI TJ 0 to +150 -40 to +150 °C Storage Temperature Range TSTG -65 to +150 °C Lead Temperature (Soldering) 10 seconds TLEAD 300 °C ESD Rating (Human Body Model) V ESD 2 kV Electrical Characteristics Unless specified:TA = 25°C. Values in bold apply over full operating ambient temperature range. SC431L 0.25% Parameter Reference Voltage SC431L 0.5% Symbol Condition Min Typ Max Min Typ Max Units VREF VZ = VREF, IZ = 10mA(1) 1.237 1.240 1.243 1.234 1.240 1.246 V 1.256 1.222 1.224 1.258 VREF Temp Deviation V D EV VZ = VREF, IZ = 10mA(1) 10 25 10 25 mV Ratio of Change in ∆VREF ∆VZ IZ = 10mA, ∆VZ = 16V to VREF -1.0 -2.7 -1.0 -2.7 mV/V Reference Input Current IREF R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) 0.15 0.5 0.15 0.5 µA IREF Temperature Deviation IREF(DEV) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) 0.1 0.4 0.1 0.4 µA IZ (OFF) VREF = 0V, VZ = 6V(3) 0.125 0.150 0.125 0.150 µA VREF = 0V, VZ = 16V(3) 0.135 0.150 0.135 0.150 VREF to Change in VZ Off-State Cathode Current 2007 Semtech Corp. 2 www.semtech.com SC431L POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified:TA = 25°C. Values in bold apply over full operating ambient temperature range. (Continued from page 2) Parameter Dynamic Output Impedance Minimum Operating Current SC431L 0.25% Symbol Condition rZ IZ (MIN) Min Typ Max f < 1kHz, VZ = VREF IZ = 100µA to 100mA(1) 0.05 VZ = VREF(1) 20 Typ Max Units 0.15 0.05 0.15 Ω 100 20 100 µA S C 431L 1% Parameter Reference Voltage SC431L 0.5% Min S C 431L 2% Symbol Condition Min Typ Max Min Typ Max Units VREF VZ = VREF, IZ = 10mA(1) 1.228 1.240 1.252 1.215 1.240 1.265 V 1.265 1.200 1.215 1.280 VREF Temp Deviation V D EV VZ = VREF, IZ = 10mA(1) 10 25 10 35 mV Ratio of Change in ∆VREF ∆VZ IZ = 10mA, ∆VZ = 16V to VREF -1.0 -2.7 -1.0 -2.7 mV/V Reference Input Current IREF R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) 0.15 0.5 0.15 0.5 µA IREF Temperature Deviation IREF(DEV) R1 = 10kΩ, R2 = ∞, IZ = 10mA(2) 0.1 0.4 0.1 0.4 µA IZ (OFF) VREF = 0V, VZ = 6V(3) 0.125 0.150 0.125 0.150 µA VREF = 0V, VZ = 16V(3) 0.135 0.150 0.135 0.150 rZ f < 1kHz, VZ = VREF IZ = 100µA to 100mA(1) 0.05 0.15 0.05 0.15 Ω IZ (MIN) VZ = VREF(1) 20 100 20 100 µA VREF to Change in VZ Off-State Cathode Current Dynamic Output Impedance Minimum Operating Current Notes: (1) See Test Circuit 1 on page 4. (2) See Test Circuit 2 on page 4. (3) See Test Circuit 3 on page 4. Recommended Operating Conditions Cathode Voltage, VZ Cathode Current, IZ 2007 Semtech Corp. Min Max Symbol VREF 16 V 100µA 100 mA 3 www.semtech.com SC431L POWER MANAGEMENT Test Circuits Test Circuit 1 VZ = VREF Test Circuit 3 Off-State Test Circuit 2 VZ > VREF Pin Configurations SOT-23-5 (Top View) SOT-23-3 (Top View) Block Diagram 2007 Semtech Corp. Symbol 4 www.semtech.com SC431L POWER MANAGEMENT Ordering Information P ackag e SOT-23-3(1)(2) TJ (°C) 0 to +150 -40 to +150 SOT-23-5(1)(2) 0 to +150 -40 to +150 Tolerance 0.25% 0.5% 1.0% 2.0% SC431LCSK-.25TR SC431LCSK-.5TR SC431LCSK-1TR SC431LCSK-2TR SC431LCSK-25TRT SC431LCSK-.5TRT SC431LCSK-1TRT SC431LCSK-2TRT SC431LISK-.25TR SC431LISK-.5TR SC431LISK-1TR SC431LISK-2TR SC431LISK-.25TRT SC431LISK-.5TRT SC431LISK-1TRT SC431LISK-2TRT SC431LC5SK.25TR SC431LC5SK-.5TR SC431LC5SK-1TR SC431LC5SK-2TR SC431LC5SK25TRT SC431LC5SK.5TRT SC431LC5SK-1TRT SC431LC5SK-2TRT SC431LI5SK.25TR SC431LI5SK-.5TR SC431LI5SK-1TR SC431LI5SK-2TR SC431LI5SK25TRT SC431LI5SK.5TRT SC431LI5SK-1TRT SC431LI5SK-2TRT Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) “T” at end of part number indicates “lead free”. This product is fully WEEE and RoHS compliant. Marking Information SOT-23-3 (Top View only) SOT-23-5 (Top View) 431L 31L SOT-23-5 (Bottom View) yyww yyww = Datecode, Example: (0015) 2007 Semtech Corp. 5 www.semtech.com SC431L POWER MANAGEMENT Typical Characteristics 300 Cathode Current vs. Cathode Current vs. Cathode Voltage Cathode Voltage 150 VZ = VREF VZ = VREF o o TA = 25 C 200 50 IZ (mA) 100 IZ (µA) TA = 25 C 100 0 0 -100 -50 -200 -100 -300 -150 -1 -0.5 0 0.5 1 1.5 -1.5 -1 -0.5 0 VZ (V) VZ (V) 1 Reference Voltage vs. Reference Input Current vs. Junction Temperature Junction Temperature 1.248 1.5 150 IZ = 10mA R1 = 10kΩ R2 = ∞ IZ = 10mA 1.246 125 IREF (nA) 1.244 VREF (V) 0.5 1.242 1.240 100 IZ = 60µA 1.238 75 1.236 50 1.234 -50 -25 0 25 50 75 100 125 -50 150 -25 0 25 50 75 100 Ratio of Delta Reference Voltage to Delta Cathode Off-State Cathode Current Voltage vs. Junction Temperature vs. Junction Temperature 1.2 1.1 250 IZ = 10mA ∆VZ = 16V to VREF 150 VZ = 16V VREF = 0V 200 0.9 0.8 0.7 IZ(off) (nA) VREF / VZ (-mV/V) 1.0 125 TJ (°C) TJ (°C) 0.6 0.5 150 100 0.4 0.3 50 0.2 0.1 0.0 VZ = 6V 0 -50 -25 0 25 50 75 100 125 150 -50 TJ (°C) 2007 Semtech Corp. -25 0 25 50 75 100 125 150 TJ (°C) 6 www.semtech.com SC431L POWER MANAGEMENT Typical Characteristics (Cont.) Reference Impedance vs. Reference Impedance Junction Temperature vs. Frequency 100 0.50 IZ = 0.1 to 100 mA VZ = VREF f < 1 kHz 0.45 0.40 TA = 25°C 10 0.35 rZ (Ω) rZ ( ) 0.30 0.25 0.20 1 0.15 0.1 0.10 0.05 0.00 -50 -25 0 25 50 75 100 125 0.01 1.E+03 150 1.E+04 TJ (°C) 1.E+05 1.E+06 1.E+07 f (Hz) Test Circuit - Small-Signal Gain and Phase Small-Signal Gain and Phase Shift 80 -180 70 -225 60 -270 50 -315 40 -360 30 -405 20 -450 10 -495 0 -540 -10 -585 -20 Phase Shift (deg) AV (dB) vs. Frequency -630 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 f (Hz) Test Circuit - Stability Stability Boundary Condition For Shunt Regulation vs. Cathode Current and Load Capacitance 3.5 TA = 25°C 3.0 Stable Stable IZ (mA) 2.5 2.0 1.5 VZ = VREF 1.0 0.5 0.0 0.001 VZ = 2V 0.01 0.1 1 10 CL (µF) 2007 Semtech Corp. 7 www.semtech.com SC431L POWER MANAGEMENT Applications Information - Stability Selection of load capacitance when using SC431L as a shunt regulator When the SC431L is used as a shunt regulator, two options for selection of CL (see diagram on page 7) 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 SC431L 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 (say) 10mA with a 0.1µF capacitor across it, it will oscillate transiently during startup 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 will probably wish 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 decoupling from causing the oscillation during the transient start-up phase. Note: if the SC431L 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. 2007 Semtech Corp. 8 www.semtech.com SC431L POWER MANAGEMENT Outline Drawing - SOT-23-3 D A DIM e1 3 1 E 2 bxN bbb e .015 0° .037 .114 .093 .051 .075 .037 .020 .022 3 .004 .008 .044 .004 .040 .020 .007 .120 .104 .055 .024 8° 0.89 1.12 0.01 0.10 0.88 0.95 1.02 0.51 0.30 0.18 0.08 2.80 2.90 3.04 2.10 2.37 2.64 1.20 1.30 1.40 1.90 BSC 0.95 BSC 0.40 0.50 0.60 (0.55) 3 0° 8° 0.10 0.20 C A B A2 A .035 .000 .035 .012 .003 .110 .082 .047 A A1 A2 b c D E E1 e e1 L L1 N 0 aaa bbb B E1 DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX aaa C 3X SEATING PLANE A1 C H GAUGE PLANE SEATING PLANE 0 0.25 C L L1 SEE DETAIL A SIDE VIEW c DETAIL A NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SOT-23-3 X Y DIM Z G C Y C E E1 G X Y Z DIMENSIONS INCHES MILLIMETERS (.087) .037 .075 .031 .039 .055 .141 (2.20) 0.95 1.90 0.80 1.00 1.40 3.60 E E1 NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2. REFERENCE IPC-SM-782A. Note: (1) Grid placement courtyard is 8 x 8 elements (4mm x 4mm) in accordance with the international grid detailed in IEC Publication 97. 2007 Semtech Corp. 9 www.semtech.com SC431L POWER MANAGEMENT Outline Drawing - SOT-23-5 A DIM e1 2X E/2 D A A1 A2 b c D E1 E e e1 L L1 N 01 aaa bbb ccc N EI 1 E 2 ccc C 2X N/2 TIPS e B D aaa C A2 DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .035 .000 .035 .010 .003 .110 .060 - .045 - .057 .006 .051 .020 .009 .118 .069 .114 .063 .110 BSC .037 BSC .075 BSC .012 .018 .024 (.024) 5 0° 10° .004 .008 .008 0.90 0.00 .90 0.25 0.08 2.80 1.50 - 1.15 - 1.45 0.15 1.30 0.50 0.22 3.00 1.75 2.90 1.60 2.80 BSC 0.95 BSC 1.90 BSC 0.30 0.45 0.60 (0.60) 5 0° 10° 0.10 0.20 0.20 A SEATING PLANE A1 C H bxN bbb C A-B D c GAGE PLANE 0.25 L 01 (L1) SEE DETAIL A DETAIL A SIDE VIEW NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SOT-23-5 X DIM (C) G Z Y P DIMENSIONS MILLIMETERS INCHES (.098) .055 .037 .024 .043 .141 C G P X Y Z (2.50) 1.40 0.95 0.60 1.10 3.60 NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 2007 Semtech Corp. 10 www.semtech.com