RC0431

www.fairchildsemi.com RC0431A (RC431A) Low-Voltage Adjustable Precision Shunt Regulator Features • • • • • • Low voltage operation to 1.24V 1% reference voltage tolerance Output voltage adjustable from Vref to 12V Low 80µA operational cathode current 0.25Ω typical output impedance TO-92, SOT23-3 and SOT23-5 packages Description The RC0431A is a low-voltage 3-terminal adjustable precision voltage reference regulator. It has an excellent thermal stability over the standard commercial temperature range. The output voltage can be set to any value between Vref (1.24V) and 12V using two external resistors. The RC0431A operates from a lower voltage (1.24V) than the traditional shunt regulator references which operate from 2.5V. When used with an optocoupler, the RC0431A will be an ideal voltage reference in an isolated feedback circuit for use in switched-mode power supplies and modular DC-DC converters. The RC0431A has a low output impedance of active output circuitry offering a very sharp turn-on characteristic. The RC0431A will be an excellent replacement for low-voltage zener diodes in many applications such as on-board regulation and adjustable power supplies. Applications • Voltage reference for discrete power circuits Symbol REF Anode Cathode 65-431A-01 Block Diagram CATHODE REF + _ Vref = 1.24V 65-431A-02 ANODE REV. 1.0.7 8/5/03 RC0431A (RC431A) PRODUCT SPECIFICATION Pin Assignments SOT-23 PACKAGE (3-Lead) (TOP VIEW) REF 1 3 CATHODE 2 ANODE SOT-23 PACKAGE (5-Lead) (TOP VIEW) NC NC CATHODE 1 2 3 4 REF 5 ANODE TO-92 PACKAGE (TOP VIEW) CATHODE ANODE REF 65-431A-03 NC = No internal connection Equivalent Schematic CATHODE REF A ANODE 65-431A-04 Absolute Maximum Ratings Ratings are over full operating free-air temperature range unless otherwise noted. Cathode voltage, VKA Continuous cathode current IK Reference current, Iref Power dissipation Storage temperature range 13.2V –20mA to 20mA –0.05mA to 3mA See Dissipation Rating Table -65° to 150°C Notes: 1. Functional operation under these conditions is not implied. Permanent damage may occur if the device is subjected to conditions outside these ratings. Recommended Operating Conditions Parameter Cathode voltage, VKA Cathode current, IK Operating temperature range in free-air, TA Min. VREF 0.1 0 Max. 12 15 70 Units V mA °C 2 REV. 1.0.7 8/5/03 PRODUCT SPECIFICATION RC0431A (RC431A) Dissipation Rating Table Package TO-92 SOT23-5 Power Rating TA ≤ 25°C 775mW 150mW Derating Factor TA ≥ 25°C 6.2mW/OC 1.2mW/oC Power Rating TA = 70°C 496mW 96mW Electrical Specifications Symbol Vref TA = 25°C (unless otherwise noted), at free-air Parameters Reference Voltage Conditions VKA = Vref, TA = 25°C IK = 10mA, TA = 0 to 70°C Vref (dev) ∆Vref ∆VKA Iref Vref deviation over full temperature range (see note 2) Ratio of Vref change in cathode voltage change Reference terminal current VKA = Vref, IK = 10mA, See note 2 and Figure 1. IK = 10mA, ∆VKA = Vref to 6V. See figure 2. IK = 10mA, R1 = 10KΩ, R2 = ∞ See figure 2. IK = 10mA, R1 = 10KΩ, R2 = ∞ See note 1 & figure 2. VKA = Vref See figure 1. VKA = 6V, Vref = 0 See figure 3. VKA = Vref, f ≤ 1KHz IK = 0.1mA to 15mA, See figure 1. Min. 1.228 1.221 4 -1.5 Typ. 1.24 Max. 1.252 1.259 12 -2.7 mV mV V µA Units V 0.15 0.5 Iref(dev) Iref deviation over full temperature range (see note 2) Minimum cathode current for regulation Off-state cathode current Dynamic impedance (see note 3) 0.05 0.3 µA IK(min) Ioff |ZKA| 55 0.001 0.25 80 0.1 0.4 µA µA Ω Notes: 1. Functional operation under these conditions is not implied. Permanent damage may occur if the device is subjected to conditions outside these ratings. 2. Full temperature range is 0°C to 70°C. 3. The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between the maximum and minimum values obtained over the rated temperature range. The average full-range temperature coefficient of the reference input voltage, ∞Vref, is defined as: ∞ V ref { V ref ( dev ) ⁄ V ref 〈 T A = 25°C〉 } × 10 〈 ppm/°C〉 = --------------------------------------------------------------------------------------------∆ TA 6 where ∆TA is the rated operating free-air temperature range of the device. ∞Vref can be positive or negative depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature. 4. The dynamic impedance is defined as: ZKA= ∆VKA/ ∆IK When the device is operating with two external resistors (see Figure 2), the total dynamic impedance of the circuit is given by: R1 ∆V Z KA = ------- ≈ Z KA ×  1 + ------   R 2 ∆I REV. 1.0.7 8/5/03 3 RC0431A (RC431A) PRODUCT SPECIFICATION Parameter Measurement Information V IN VIN IK VOUT R1 Iref IK V OUT R2 V ref 65-431A-05 V ref 65-431A-06 Figure 1. Test Circuit for VKA = VREF, VOUT = VKA = VREF Figure 2. Test Circuit for VKA > VREF, VOUT = VKA = VREF x (1+R1/R2) + IREF x R1 V IN VOUT I OFF 65-431A-07 Figure 3. Test Circuit for IOFF Iref–Reference Input Current (nA) Vref–Reference Voltage (V) 1.250 1.246 1.242 1.238 lk = 10 mA 250 200 150 100 lk = 10 mA, R1 = 10 kΩ, R2 = infinite 1.230 –40 –20 0 20 40 60 80 100 50 –40 –20 0 20 40 60 80 100 Tj—Junction Temp. (°C) Tj—Junction Temp. (°C) Figure 4. Reference Voltage vs. Junction Temp. VKA = Vref, T = 25°C Figure 5. Reference Input Current vs. Junction Temp. VKA = Vref, T = 25°C 150 120 90 60 30 0 –30 –60 –90 –120 –150 –1 –0.5 0 15 lk–Cathode Current (mA) 10 5 0 –5 –10 –15 -1 –0.5 0 0.5 1 1.5 VKA–Cathode Voltage (V) lk–Cathode Current (µA) 0.5 1 1.5 VKA–Cathode Voltage (V) Figure 7. Cathode Current vs. Cathode Voltage Figure 6. Cathode Current vs. Cathode Voltage 4 REV. 1.0.7 8/5/03 PRODUCT SPECIFICATION RC0431A (RC431A) Ioff–Off State Cathode Current (nA) 40.0 30.0 20.0 10.0 Del Vref / Del Vka (mV/V) VKA = 6V, Vref = 0V 1.4 1.2 1.0 0.8 0.6 0.4 0.2 lk = 10 mA, Del VKA = Vref to 6V 0.0 –40 –20 0 20 40 60 80 100 0.0 –40 –20 0 20 40 60 80 100 Tj—Junction Temperature (°C) Tj—Junction Temperature (°C) Figure 8. Off-State Cathode Current vs. Junction Temperature 100 |Zka|–Reference Impedance (Ω) Figure 9. Ratio of Delta Reference Voltage to Delta Cathode Voltage vs. Junction Temperature 10 1 100Ω OUTPUT IK 100Ω + 0.1 0.01 1000 10000 100000 f–Frequency (Hz) 1000000 10000000 GND Figure 10. Reference Impedance vs. Frequency Figure 11. Test Circuit for Reference Impedance REV. 1.0.7 8/5/03 5 RC0431A (RC431A) PRODUCT SPECIFICATION Mechanical Dimensions TO-92 Package Inches Min. A b c øD E e e1 L S α .170 .015 .014 .175 .125 .095 .045 .500 .080 4° Max. .210 .021 .020 .205 .165 .105 .055 — .115 6° Millimeters Min. 4.32 .38 .36 4.45 3.18 2.41 1.14 12.70 2.03 4° Max. 5.33 .53 .51 5.21 4.19 2.67 1.40 — 2.92 6° Notes: Notes 1. Package outline exclusive of any mold flashes dimension. 2. Package outline exclusive of burr dimension. Symbol S c E-PIN C 1/16 A b e α E e1 øD L 6 REV. 1.0.7 8/5/03 PRODUCT SPECIFICATION RC0431A (RC431A) Mechanical Dimensions (continued) SOT23-5 Package SOT23 5-Lead Symbol A A1 B c D E e e1 H L Inches Min. .035 .000 .008 .003 .106 .059 Max. .057 .006 .020 .010 .122 .071 Millimeters Min. .90 .00 .20 .08 2.70 1.50 Max. 1.45 .15 .50 .25 3.10 1.80 Notes .037 BSC .075 BSC .087 .126 .004 .024 0 10 .95 BSC 1.90 BSC 2.20 3.20 .10 .60 0 10 Notes: 1. Package outline exclusive of mold flash & metal burr. 2. Package outline exclusive of solder plating. 3. EIAJ Ref Number SC-74A. B e E H e1 D L A A1 c REV. 1.0.7 8/5/03 7 RC0431A (RC431A) PRODUCT SPECIFICATION Mechanical Dimensions (continued) SuperSOT™-3 Package SuperSOT-3 (FS PKG Code 32) 1:1 Scale 1:1 on letter size paper Di mensions shown below are in: inches [mil limeters] Part Weight per unit (gram): 0.0097 8 REV. 1.0.7 8/5/03 RC0431A (RC431A) PRODUCT SPECIFICATION Ordering Information Product Number RC0431AM RC0431AT RC0431AS Package SOT23-5 TO-92 SOT23-3 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. www.fairchildsemi.com 8/5/03 0.0m 002 Stock#DS3000431A  2003 Fairchild Semiconductor Corporation 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.