Document
ADJUSTABLE SHUNT REGULATOR
SC431
April 13, 1998
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC431 is a three terminal adjustable shunt regulator with thermal stability guaranteed over temperature. The output voltage can be adjusted to any value from 2.5V (VREF) to 36V with two external resistors. The SC431 has a typical dynamic output impedance of 0.25Ω. Active output circuitry provides a very sharp turn on characteristic, making the SC431 an excellent replacement for zener diodes. The SC431 shunt regulator is available in three voltage tolerances (0.5%, 1.0% and 2.0%) and three package options (SOT-23-3, SO-8 and TO-92). The three voltage tolerances allow the designer the opportunity to select the proper cost/tolerance for their application.
FEATURES • Wide operating current range 100µA to 150mA • Low dynamic output impedance 0.25 Ω typ. • Trimmed bandgap design + 0.5% • Alternate for TL431, LM431 & AS431 APPLICATIONS • Linear Regulators • Adjustable Supplies • Switching Power Supplies • Battery Operated Computers • Instrumentation • Computer Disk Drives
PIN CONFIGURATIONS
SOT-23 -3 Lead (Top View)
BLOCK DIAGRAM
SOIC 8 Lead (Top View)
SYMBOL DIAGRAM
TO-92 (Top View)
1 © 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
ADJUSTABLE SHUNT REGULATOR
SC431
April 13, 1998
ABSOLUTE MAXIMUM RATINGS
Parameter Cathode Voltage Continous Cathode Current Reference Input Current Operating Junction Temperature Range Storage Temperature Range Thermal Resistance TO-92 SO-8 SOT-23 Power Dissipation at TA = 25°C TO-92 SO-8 SOT-23 Lead Temperature (Soldering) 10 seconds Symbol VZ IZ IREF TJ TSTG θJA Maximum 37 150 10 -40 to +150 -65 to +150 160 175 410 0.78 0.71 0.30 260 Units V mA mA °C °C °C/W
PD
W
TLEAD
°C
ORDERING INFORMATION
PACKAGE 0.5% SO-8
(1) (1)
TOLERANCE 1.0% SC431CS - 1 SC431CSK - 1 SC431CZ - 1 2.0% SC431CS - 2 SC431CSK - 2 SC431CZ - 2 T/R Quantity 2.5K 3K TR=3K, TA=2K
SC431CS - .5 SC431CSK - .5 SC431CZ - .5
SOT-23 TO-92
(1)(2)
Notes: (1) Add suffix ‘TR’ for Tape & Reel. (2) Add suffix ‘TA’ for Tape Ammo.
2 © 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
ADJUSTABLE SHUNT REGULATOR
SC431
April 13, 1998
ELECTRICAL CHARACTERISTICS
Unless specified, TA = 25°C
SC431 0.5% Parameter Reference Voltage VREF Temp Deviation Ratio of Change in VREF to Change in Cathode Voltage Symbol VREF VDEV
∆ V REF ∆VZ
SC431 1% MIN TYP MAX
SC431 2% MIN TYP MAX UNITS V
Condition VZ = VREF IZ = 10mA (test circuit 1) TA = 25°C
MIN
TYP
MAX
2.482 2.495 2.507 2.470 2.495 2.520 2.445 2.495 2.545
TA = -40 to +85°C, VZ = VREF (test circuit 1) IZ = 10mA IZ = 10mA, ∆VZ = 10V to VREF IZ = 10mA, ∆VZ = 36V to 10V
8
17
8
25
15
30
mV
-0.5 -1.0 0.5
-2.7 -2.0 4
-0.5 -1.0 0.5
-2.7 -2.0 4
-0.5 -1.0 0.5
-2.7 mV/V -2.0 4 µA
Reference Input Current
IREF
R1 = 10kΩ, R2 = ∞, IZ = 10mA (test circuit 2) TA = -40 to +85°C, R1 = 10kΩ, R2 = ∞, IZ =10mA (test circuit 2) VREF = 0V, VZ = 36V (test circuit.