SC431L Low Voltage Adjustable Shunt Regulator POWER MANAGEMENT Description Features The SC431L is a three terminal adjustable shunt (cid:139) Low voltage operation (down to 1.24V) regulator with thermal stability guaranteed over (cid:139) Wide operating current range 100µA to 100mA temperature. The output voltage can be adjusted to any (cid:139) Low dynamic output impedance 0.05 Ω typ. value from 1.24V (V ) to 20V with two external REF (cid:139) Trimmed bandgap design ± 0.25% resistors. The SC431L has a typical dynamic output (cid:139) Upgrade for TLV431A impedance of 0.05Ω. Active output circuitry provides a (cid:139) SOT-23-3 and SOT-23-5 packages. Also available in very sharp turn on characteristic, making the SC431L an Lead-free package, fully WEEE and RoHS compliant excellent replacement for zener diodes. Applications The SC431L shunt regulator is available with four volt- age tolerances (0.25%, 0.5%, 1.0% and 2.0%), two (cid:139) Linear Regulators operating temperature ranges (commercial and indus- (cid:139) Adjustable Supplies trial) and two package options (SOT-23-3 and SOT-23- (cid:139) Switching Power Supplies 5). This allows the designer the opportunity to select the (cid:139) Battery Operated Computers optimum combination of cost and performance for their (cid:139) Instrumentation application. (cid:139) Computer Disk Drives Typical Application Circuit(1)(2) Notes: 1) Set V according to the following equation: OUT  R1 V =V 1+ +I R1 OUT REF R2 REF 2) Choose the value for R as follows: • The maximum limit for R should be such that the cathode current, I , is greater than the minimum Z operating current (100µA) at V . IN(MIN) • The minimum limit for R should be such that I does Z not exceed 100mA under all load conditions, and the instantaneous turn-on value for I does not exceed Z 150mA. Both of the following conditions must be met: V R ≥ IN(max) (to limit instantaneous turn-on I ) min 150mA Z V −V R ≥ IN(max) OUT (to limit I under normal min I +100mA Z OUT(min) operating conditions) Revision: May 16, 2008 1 www.semtech.com

SC431L POWER MANAGEMENT Absolute Maximum Ratings Parameter Symbol Maximum Units Cathode Voltage V 20 V Z Continous Cathode Current I 100 mA Z Reference InputCurrent I 3 mA REF PowerDissipationatT =25°C A SOT-23-3 P 0.37 W D SOT-23-5 0.49 ThermalResistance SOT-23-3 θ 336 °C/W JA SOT-23-5 256 Operating AmbientTemperature Range SC431LC T 0 to +70 °C A SC431LI -40 to +85 Operating JunctionTemperature Range SC431LC T 0 to +150 °C J SC431LI -40 to +150 Storage Temperature Range T -65 to +150 °C STG Lead Temperature (Soldering)10 seconds T 300 °C LEAD ESD Rating (HumanBodyModel) V 2 kV ESD Electrical Characteristics Unless specified:T = 25°C. Values in bold apply over full operating ambient temperature range. A SC431L 0.25% SC431L 0.5% Parameter Symbol Condition Min Typ Max Min Typ Max Units Reference Voltage V V =V ,I =10mA(1) 1.237 1.240 1.243 1.234 1.240 1.246 V REF Z REF Z 1.224 1.256 1.222 1.258 V Temp Deviation V V =V ,I =10mA(1) 10 25 10 25 mV REF DEV Z REF Z Ratio ofChange in ∆VREF IZ=10mA,∆VZ=16V to VREF -1.0 -2.7 -1.0 -2.7 mV/V V to Change inV ∆VZ REF Z Reference Input I R1 =10kΩ,R2 =∞, 0.15 0.5 0.15 0.5 µA REF Current I =10mA(2) Z I Temperature I R1 =10kΩ,R2 =∞, 0.1 0.4 0.1 0.4 µA REF REF(DEV) Deviation I =10mA(2) Z Off-State Cathode I V =0V,V =6V(3) 0.125 0.150 0.125 0.150 µA Z(OFF) REF Z Current V =0V,V =16V(3) 0.135 0.150 0.135 0.150 REF Z  2008 Semtech Corp. 2 www.semtech.com

SC431L POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified:T = 25°C. Values in bold apply over full operating ambient temperature range. A (Continued frompage 2) SC431L 0.25% SC431L 0.5% Parameter Symbol Condition Min Typ Max Min Typ Max Units Dynamic Output r f<1kHz,V =V 0.05 0.15 0.05 0.15 Ω Z Z REF Impedance I =100µA to 100mA(1) Z MinimumOperating I V =V (1) 20 100 20 100 µA Z(MIN) Z REF Current SC431L 1% SC431L 2% Parameter Symbol Condition Min Typ Max Min Typ Max Units Reference Voltage V V =V ,I =10mA(1) 1.228 1.240 1.252 1.215 1.240 1.265 V REF Z REF Z 1.215 1.265 1.200 1.280 V Temp Deviation V V =V ,I =10mA(1) 10 25 10 35 mV REF DEV Z REF Z Ratio ofChange in ∆V I =10mA,∆V =16V to V -1.0 -2.7 -1.0 -2.7 mV/V REF Z Z REF ∆V V to Change inV Z REF Z Reference Input I R1 =10kΩ,R2 =∞, 0.15 0.5 0.15 0.5 µA REF Current I =10mA(2) Z I Temperature I R1 =10kΩ,R2 =∞, 0.1 0.4 0.1 0.4 µA REF REF(DEV) Deviation I =10mA(2) Z Off-State Cathode I V =0V,V =6V(3) 0.125 0.150 0.125 0.150 µA Z(OFF) REF Z Current V =0V,V =16V(3) 0.135 0.150 0.135 0.150 REF Z Dynamic Output r f<1kHz,V =V 0.05 0.15 0.05 0.15 Ω Z Z REF Impedance I =100µA to 100mA(1) Z MinimumOperating I V =V (1) 20 100 20 100 µA Z(MIN) Z REF 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 Min Max Symbol Cathode Voltage,V V 16 V Z REF Cathode Current,I 100µA 100 mA Z  2008 Semtech Corp. 3 www.semtech.com

SC431L POWER MANAGEMENT Test Circuits Test Circuit 1 Test Circuit 2 Test Circuit 3 V = V V > V Off-State Z REF Z REF Pin Configurations SOT-23-3 (Top View) SOT-23-5 (Top View) Block Diagram Symbol  2008 Semtech Corp. 4 www.semtech.com

SC431L POWER MANAGEMENT Ordering Information Package T (°C) Tolerance J 0.25% 0.5% 1.0% 2.0% SOT-23-3(1)(2) 0 to +150 SC431LCSK-.25TR SC431LCSK-.5TR SC431LCSK-1TR SC431LCSK-2TR SC431LCSK-25TRT SC431LCSK-.5TRT SC431LCSK-1TRT SC431LCSK-2TRT -40 to +150 SC431LISK-.25TR SC431LISK-.5TR SC431LISK-1TR SC431LISK-2TR SC431LISK-.25TRT SC431LISK-.5TRT SC431LISK-1TRT SC431LISK-2TRT SOT-23-5(1)(2) 0 to +150 SC431LC5SK.25TR SC431LC5SK-.5TR SC431LC5SK-1TR SC431LC5SK-2TR SC431LC5SK25TRT SC431LC5SK.5TRT SC431LC5SK-1TRT SC431LC5SK-2TRT -40 to +150 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) SOT-23-5 (Top View) (0 to +150°C) (-40 to +150°C) (0 to +150°C) 3 1 L L 5 I 431L SOT-23-3 (Top View only) SOT-23-5 (Bottom View) SOT-23-5 (Bottom View) (-40 to +150°C) yyww yyww 3 L I yyww = Datecode, yyww = Datecode, Example: (0015) Example: (0115)  2008 Semtech Corp. 5 www.semtech.com

SC431L POWER MANAGEMENT Typical Characteristics Cathode Current vs. Cathode Current vs. Cathode Voltage Cathode Voltage 300 150 VZ = VREF VZ = VREF 200 TA = 25oC 100 TA = 25oC 100 50 A) A) µ 0 m 0 I (Z I (Z -100 -50 -200 -100 -300 -150 -1 -0.5 0 0.5 1 1.5 -1.5 -1 -0.5 0 0.5 1 1.5 V (V) V (V) Z Z Reference Voltage vs. Reference Input Current vs. Junction Temperature Junction Temperature 1.248 150 IZ = 10mA IZ = 10mA 1.246 R1 = 10kΩ R2 = ∞ 125 1.244 V (V)REF 11..224402 I (nA)REF 100 I = 60µA Z 1.238 75 1.236 1.234 50 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 50 75 100 125 150 TJ (°C) TJ (°C) Ratio of Delta Reference Voltage to Delta Cathode Off-State Cathode Current Voltage vs. Junction Temperature vs. Junction Temperature 1.2 250 1.1 IZ = 10mA VREF = 0V VZ = 16V ∆VZ = 16V to VREF 1.0 200 0.9 V/V) 0.8 V/V (-mREFZ 0000....4567 I (nA)Z(off) 110500 0.3 0.2 50 0.1 V = 6V 0.0 0 Z -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 50 75 100 125 150 TJ (°C) TJ (°C)  2008 Semtech Corp. 6 www.semtech.com

SC431L POWER MANAGEMENT Typical Characteristics (Cont.) Reference Impedance vs. Reference Impedance Junction Temperature vs. Frequency 0.50 100 IZ = 0.1 to 100 mA TA = 25°C 0.45 VZ = VREF 0.40 f < 1 kHz 10 0.35 0.30 r ()Z 0.25 Ωr ()Z 1 0.20 0.15 0.1 0.10 0.05 0.00 0.01 -50 -25 0 25 50 75 100 125 150 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 TJ (°C) f (Hz) Small-Signal Gain and Phase Shift Test Circuit - Small-Signal Gain and Phase vs. Frequency 80 -180 70 -225 60 -270 50 -315 g) e 40 -360 d A (dB)V 2300 --445005 se Shift ( a h 10 -495 P 0 -540 -10 -585 -20 -630 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 f (Hz) Stability Boundary Condition For Shunt Regulation Test Circuit - Stability vs. Cathode Current and Load Capacitance 3.5 T = 25°C A 3.0 Stable Stable 2.5 A) 2.0 m I (Z 1.5 V = V Z REF 1.0 0.5 V = 2V Z 0.0 0.001 0.01 0.1 1 10 C (µF) L  2008 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 C (see diagram on page 7) are L 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 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 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.  2008 Semtech Corp. 8 www.semtech.com

SC431L POWER MANAGEMENT Outline Drawing - SOT-23-3 D A DIMENSIONS INCHES MILLIMETERS e1 DIM MIN NOMMAX MIN NOMMAX A .035 - .044 0.89 - 1.12 3 A1 .000 - .004 0.01 - 0.10 B A2 .035 .037 .040 0.88 0.95 1.02 b .012 - .020 0.30 - 0.51 c .003 - .007 0.08 - 0.18 D .110 .114 .120 2.80 2.90 3.04 E E .082 .093 .104 2.10 2.37 2.64 E1 E1 .047 .051 .055 1.20 1.30 1.40 e .075 1.90 BSC e1 .037 0.95 BSC L .015 .020 .024 0.40 0.50 0.60 L1 .022 (0.55) N 3 3 1 2 0 0° - 8° 0° - 8° aaa .004 0.10 bxN bbb .008 0.20 e bbb C A B A A2 3X aaa C SEATING PLANE A1 C H GAUGE 0 c SEATING PLANE PLANE 0.25 C L SIDE VIEW SEE DETAIL A L1 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 DIMENSIONS DIM INCHES MILLIMETERS C (.087) (2.20) Z G C E .037 0.95 E1 .075 1.90 G .031 0.80 X .039 1.00 Y .055 1.40 Z .141 3.60 Y 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.  2008 Semtech Corp. 9 www.semtech.com

SC431L POWER MANAGEMENT Outline Drawing - SOT-23-5 DIMENSIONS A INCHES MILLIMETERS DIM MIN NOMMAX MIN NOMMAX e1 D A .035 - .057 0.90 - 1.45 A1 .000 - .006 0.00 - 0.15 N A2 .035 .045 .051 .90 1.15 1.30 2X E/2 b .010 - .020 0.25 - 0.50 EI E c .003 - .009 0.08 - 0.22 D .110 .114 .118 2.80 2.90 3.00 1 2 E1 .060 .063 .069 1.50 1.60 1.75 ccc C E .110 BSC 2.80 BSC e .037 BSC 0.95 BSC 2X N/2 TIPS e1 .075 BSC 1.90 BSC e L .012 .018 .024 0.30 0.45 0.60 B L1 (.024) (0.60) N 5 5 01 0° - 10° 0° - 10° aaa .004 0.10 D bbb .008 0.20 aaa C ccc .008 0.20 A2 A SEATING PLANE C A1 H bxN bbb C A-B D GAGE c 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-H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SOT-23-5 X DDIIMMEENNSSIIOONNSS DDIIMM IINNCCHHEESS MMIILLLLIIMMEETTEERRSS CC (.098) (2.50) GG .055 1.40 (C) G Z PP .037 0.95 Y XX .024 0.60 YY .043 1.10 P ZZ .141 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  2008 Semtech Corp. 10 www.semtech.com