ADJUSTABLE SHUNT REGULATOR SC431 TEL: 805-498-2111 FAX: 805-498-3804 PRELIMINARY FEATURES SYMBOL / BLOCK DIAGRAM * Wide Operating Current Range Cathode Cathode 60yUA to 150mA * Low Dynamic Output Impedance Ref + 0.25 Typ. Anode A * Trimmed Bandgap Design +0.25% * Alternate for TL431 Anode APPLICATIONS . | PIN CONFIGURATIONS (top view): Linear Regulators TO-92 SOT-23 Adjustable Supplies * Switching Power Supplies Cathode > 1/71 cathode * Battery Operated Computers Anode anode [| 3 * Instrumentation + || Reterence Computer Disk Drives Reference DESCRIPTION SOT-89 $0-8 The SC431 is a three terminal adjustable Sy Cathode (1 8 [1] Reference shunt regulator. The SC431s thermal stabili- Anode] 2. = 7 [I Anode ty is guaranteed over the temperature range. 1 2 3/| Anode [}3 6 [ ] Anode The output voltage may be adjusted to any UU [] NCT}4 sinc value between Vref and 20 volts with two external resistors. The SC431 has a typical dynamic output impedance of 0.250. Active ABSOLUTE MAXIMUM RATINGS Reference Anode Cathode output circuitry provides a very sharp turn on Parameter Symbol Maximum Units characteristic, making the SC431 an excel- Cathode Voltage 8 VKA 40 &#&V lent replacement for Zener diodes. Continuous Cathode . p Current Range Ika 150 mA DEVICE SELECTION GUIDE Reference Input IREF 10 mA CurrentRange | SC431CX-XX Operating Junction Ty -40 to +125 C package! | L tape REEL OPTION Temperature Range | Z = TO-92 TR: 2000 PCS, TO-92 Storage Temperature 3 $8 = SO-8 2500 PCS, SO-8, SOT-89 Range stg 65 to +150 C SP = SOT-89 TC: 3000 PCS, SOT-23 (7 REEL) Thermal Resistance 9 CW SK = SOT-23 TG: 10000 PCS, SOT-23 (13" REEL) TO-92 vA 460 TA: 2000 PCS, TO-92 (AMMQ) SO-8 175 BLANK: 98 PCS, SO-8 (TUBES) SOT-89 110 2000 PCS (BAG) SOT-23 ee 410 TOLERANCE Power Dissipation Po Ww 5: 0.5% TO-92 0.78 1: 1% SO-8 0.71 2: 2% SOT-89 4.13 ___SOT-23 | a _, 0:30 Lead Temperature 6 (Soldering) 10 Sec. T LEAD . 260 Cc 16 1996 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320ADJUSTABLE SHUNT REGULATOR PRELIMINARY ELECTRICAL CHARACTERISTICS SC431 0.5% $C431 1.0% TEL: 805-498- $C431 2111 FAX: 805-498-3804 $C431 2.0% Parameter Symbol Conditions MIN | TYP | MAX] MIN | TYP | MAX] MIN | TYP | MAX |UNITS Reference Viet TA = 25C 2.482] 2.495] 2.507 | 2.470] 2.495| 2.520] 2.445] 2.495) 2.545| V Voltage Veet TA = 0 to 70C 2.459 2.530 | 2.447 2.543] 2.422 2.568 (test circuit 1) Vref Temp 0<Ta< 70C Deviation AV ei AT (test circuit 1) -0.17 | -0.32 -0.17 | -0.32 -0.17 | -0.32 |mv/c Ratio of Change Viet Ik = 10mMA, AVKA = 10V to Vref -1.0 | -2.7 -4.0 | -2.7 -1.0 | -2.7 in Vret to V mvV/V Cathode Voltage KA Ik = 10mA, AVKA = 20V to 10V -1.0 | -2.0 -1.0 | -2.0 -1.0 | -2.0 Ref Input Current let (test circuit 2) 0.01 | 0.1 0.01] 0.1 0.01 | 0.1 yA lray Temp TA = 0 to 70C Deviation Alret (test circuit 2) 0.4] 1.2 0.4 | 1.2 04] 1.2 | pA Vref = OV, VKA = 20V Ik (off , Leakage k (off) (test circuit 3) 0.04] 1 0.04] 1 0.04) 1 yA Dyn. Out. f < 1KHz, VKA = Vret Impedance ZKA Ik = 10HA to 20mA 0.25 | 0.6 0.25] 0.6 0.25] 0.6 Q (test circuit 1) Minimum _ Operating Current Imin (test circuit 1 ) 60 60 60 yA TEST CIRCUITS AA . AA . VKA _ AA S VKA IK VKA = V Ref rz | Ref | R1 Ire _ y Lt Vref : R2 | K off Test Circuit 1: Test Circuit 2 : Test Circuit 3 : VKA = Vref VKA > Vref Off State Current RECOMMENDED SOT PACKAGE MARKING INFORMATION Since the SOT packages can only have 3 characters for OPERATING CONDITIONS marking, a code must be used for the part identification and specifications. Three fields are defined below to explain the Min Max Symbol various combinations of product markings. Cathode Voltage, Vina Vref 36 Vv Field 1 Field 2 Field 3 a a nee me E = Adj. Reference Az=1.25 volts 0O=+0.25% Cathode Current, Ika 1 100 mA D = Diode Reference B = 2.5 volts 1 = +0.5% T = Low Tempco Diode Ref. C = 3.3 volts 2= 41.0% D=2.55 volts 3=+42.0% E =5 volts 4 = +3.0% oan F = 10 volts 5 = +5.0% Example: adjustable voltage reference @ 2.5 volts and +0.5% initial tolerance is represented by the 3 character (field) marking scheme E|B|1. 1996 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 17ADJUSTABLE SHUNT REGULATOR SC431 TEL: 805-498-2111 FAX: 805-498-3804 PRELIMINARY TYPICAL CHARACTERISTICS REFERENCE INPUT CURRENT vs AMBIENT TEMPERATURE REFERENCE INPUT VOLTAGE vs AMBIENT TEMPERATURE 5.00 coe ones pores 2.580 : i : VKA = Vliref) 4.50 - See : meee { 2.560 < Ika = 10mA~ VuREF) = 2.545 = 4.00 = ; 2.540 + - 3 ! = = 350 - - eee ed . pee o 5 & 2.520 5 3.00 S 2 2.500 : . ~ B 250 3 VureF) = 2.495 Q c Z 2-480 aan : @ 2.00 8 c 2.460 2 1.50 5 3 3 2 2.440 co L . 1.00 ! VUREF) = 2.445 0.50 . . woe . . 2.420 ia 0.00 vee oo mos 2.400 | | 70 45 -20 5 30 55 80 105 130 55-3005 20 45 70 95 120 Ambient Temperature (C} Ambient Temperature (C) CATHODE CURRENT vs CATHODE VOLTAGE PULSE RESPONSE 800 5 Input = 5V 700 4 600 - < 500 S 3 E 400 - 2 2 & Output 2 . oS - 3 300 S 2 + 2 200 3 > | & 100 8 0 A 0 . -100 200 ~~ me oo aT A 0 1 2 3 0 1 2 3 4 5 6 7 8 9 10 11 42 Cathode Voltage (V) Time (uS) STABILITY BOUNDARY CONDITIONS 140 A Vika = Vrat STABLE 120 7-8 VKA = 5V C VKA=10V D Vka = 15V = _. All@ I = 10MA = 100 TA = 25C & 80 5 3 2 60 2 STABLE : Oo 40 20 0 - 0.0001 0,001 0.01 o4 1 10 Load Capacitance (pf} 18 1996 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320