LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS T H E I N F I N I T E P O W E R O F I P N N O VA T I O N R O D U C T I O N DESCRIPTION The LX432 series are low-voltage precision adjustable shunt regulators with a reference voltage of 1.24V. The output voltage may be set to any value between 1.24V and 20V by two external resistors. These devices offer low output impedance for improved load regulation — typical output impedance is 250mΩ. The LX432 series operates with an operating current as low as 80µA, making these devices suitable for portable and micropower applications. D A T A S H E E T K E Y F E AT U R E S ■ ■ ■ ■ Low Voltage Operation: 1.24V Reference Initial Voltage Reference Accuracy 1% Adjustable Output Voltage From VREF To 20V Typical Output Dynamic Impedance Less Than 250mΩ ■ Sink Current Capability 80µA To 20mA ■ Direct Alternative To TLV431 Low voltage operation enables the LX432 to be used in the feedback loop of isolated low voltage power supplies. The minimum output voltage is determined by the LX432 output voltage plus the forward voltage drop of the opto-coupler LED (typically 1.24 + 1.4 = 2.64V minimum). See Figure 10. The LX432 is offered in 3 and 5-pin SOT-23 or TO-92 packages, and is a dropin replacement for the TLV431 and SC431L devices. A P P L I C AT I O N S ■ ■ ■ ■ IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com. Low Voltage Adjustable Power Supplies Instrumentation Computers Portable Equipment PRODUCT HIGHLIGHT T Y P I C A L P R O G R A M M A B L E V O LTA G E REFERENCE CIRCUIT VIN VKA R1 Cathode LX432 Reference Anode R2 GND PA C K A G E O R D E R I N F O R M AT I O N TA (°C) 0 to 70 -40 to 85 SOT-23 SC Plastic 3-pin LX432CSC LX432ISC SOT-23 SE Plastic 5-pin LX432CSE LX432ISE TO-92 LP Plastic 3-pin LX432CLP LX432ILP Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX432CSET) TO-92 (LP) package also available in ammo-pack. Copyright © 1999 Rev. 1.0 9/99 LINFINITY MICROELECTRONICS INC. 11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570 1 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N A B S O L U T E M A X I M U M R AT I N G S D A T A S H E E T PACKAGE PIN OUTS (Note 1) Cathode to Anode Voltage (VKA) ................................................................. -0.3V to +20V Reference Input Current (IREF) .................................................................... -50µA to 10µA Continuous Cathode Current (IK) ............................................................. -25mA to 25mA Operating Junction Temperature Plastic (SC, SE & LP Packages) ............................................................................. 150°C Storage Temperature Range ...................................................................... -65°C to 150°C Lead Temperature ..................................................................................................... 300°C Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal. Pin numbers refer to DIL packages only. T H E R M A L D ATA SC PACKAGE: Thermal Resistance - Junction to Ambient, θJA (PC-Mounted) 220°C/W (Non-PC Mounted) 410°C/W (PC-Mounted) 220°C/W (Non-PC Mounted) 410°C/W SE PACKAGE: Thermal Resistance - Junction to Ambient, θJA ANODE 2 CATHODE 1 REF 3 SC PACKAGE — 3-Pin (Top View) N.C. 1 N.C. 2 CATHODE 3 5 ANODE 4 REF SE PACKAGE — 5-Pin (Top View) LP PACKAGE: Thermal Resistance-Junction to Ambient, θJA 156°C/W Junction Temperature Calculation: TJ = TA + (PD x θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow BLOCK DIAGRAM 3. CATHODE 2. ANODE 1. REF LP PACKAGE (Top View) Cathode (K) Ref (R) VREF Anode (A) 2 Copyright © 1999 Rev. 1.0 9/99 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N D A T A S H E E T ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply over the operating ambient temperatures for LX432C with 0°C ≤ TA ≤ 70°C, and the LX432I with -40°C ≤ TA ≤ 85°C.) Parameter Symbol Reference Voltage Reference Voltage Drift (Note 2) VREF ∆VREF Ratio Of VREF Change In Cathode Voltage Change (Note 3) Reference Terminal Current Reference Current Drift (Note 2) ∆VREF ∆VKA IREF ∆IREF Minimum Cathode Current For Regulation Dynamic Impedance Off-state Cathode Current IK (MIN) ZKA IOFF Test Conditions IK = 10mA, VKA = VREF, TA = 25°C IK = 10mA, VKA = VREF, 0°C ≤ TA ≤ 70°C IK = 10mA, VKA = VREF, -40°C ≤ TA ≤ 85°C IK = 10mA, VKA = VREF to 16V, TA = 25°C IK = 10mA, VKA = VREF, TA = 25°C, R1=10kΩ, R2 = Open IK = 10mA, VKA = VREF, 0°C ≤ TA ≤ 70°C IK = 10mA, VKA = VREF, -40°C ≤ TA ≤ 85°C VKA = VREF, TA = 25°C IK = 0.1mA to 15mA, VKA = VREF, TA = 25°C VKA = 16V, TA = 25°C Min. 1.228 LX432 Typ. Max. Units 1.24 3 4 -1 1.252 12 20 -2.7 V mV mV mV/V 0.1 0.05 0.1 55 0.2 0.004 0.5 0.3 0.4 80 0.4 µA µA µA µA Ω µA Note 2. These parameters are guaranteed by design. Note 3. ∆VREF ∆VKA Copyright © 1999 Rev. 1.0 9/99 Ratio of change in reference input voltage to the change in cathode voltage. 3 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N D A T A S H E E T GRAPH / CURVE INDEX FIGURE INDEX Characteristic Curves 4 Parameter Measurement Information FIGURE # FIGURE # 1. Reference Voltage vs. Junction Temperature 9. 2. Reference Current vs. Junction Temperature 10. Test Circuit For VKA > VREF 3. Cathode Current vs. Cathode Voltage 11. Test Circuit For IOFF 4. ∆VREF / ∆VKA vs. Junction Temperature 5. Dynamic Impedance vs. Junction Temperature 6. Minimum Cathode Current For Regulation vs. Junction Temperature FIGURE # 7. Off-State Current vs. Junction Temperature 12. Flyback With Isolation Using LX431 Or LX431A As Voltage Reference And Error Amplifier 8. Equivalent Input Noise Voltage vs. Frequency 13. LX432 In 3.3V To 2.7V Low Dropout Regulator Application Test Circuit For VKA = VREF Typical Applications Copyright © 1999 Rev. 1.0 9/99 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N D S A T A H E E T CHARACTERISTIC CURVES 0.2 IREF : Reference Current ( A) VREF : Reference Voltage (V) 1.25 1.245 1.24 1.235 0.16 0.12 0.08 0.04 0 1.23 -40 -30 -20 -10 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 TJ : Junction Temperature ( C) TJ : Junction Temperature ( C) FIGURE 1 — Reference Voltage vs. Junction Temperature FIGURE 2 — Reference Current vs. Junction Temperature 800 -1.200 600 -1.000 500 ∆VREF /∆VKA (mV/V) IK : Cathode Current ( A) 700 400 300 200 100 0 -0.800 -0.600 -0.400 -100 -200 -0.200 -1 -0.5 0 0.5 1 TJ : Junction Temperature (V) FIGURE 3 — Cathode Current vs. Cathode Voltage Copyright © 1999 Rev. 1.0 9/99 1.5 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 TJ : Junction Temperature ( C) FIGURE 4 — ∆VREF / ∆VKA vs. Junction Temperature 5 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N D S A T A H E E T CHARACTERISTIC CURVES 120 Minimum Cathode Current ( A) Dynamic Impedance (Ohm) 1.000 0.800 0.600 0.400 0.200 0.000 100 80 60 40 20 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 -40 -30 -20 -10 TJ : Junction Temperature ( C) 0 10 20 30 40 50 60 70 80 90 TJ : Junction Temperature ( C) FIGURE 5 — Dynamic Impedance vs. Junction Temperature FIGURE 6 — Minimum Cathode Current for Regulation vs. Junction Temperature 0.012 350 Noise Voltage (nV/sqrt(Hz)) Off-State Current ( A) 0.010 0.008 0.006 0.004 0.002 0.000 250 200 150 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 TJ : Junction Temperature ( C) FIGURE 7 — Off-State Current vs. Junction Temperature 6 300 10 100 1K 10K 100K Frequency (Hz) FIGURE 8 — Equivalent Input Noise Voltage vs. Frequency Copyright © 1999 Rev. 1.0 9/99 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P R O D U C T I O N D A T A S H E E T PA R A M E T E R M E A S U R E M E N T I N F O R M AT I O N VKA Input VKA Input IK IK R1 IREF R2 VREF VREF FIGURE 10 — Test Circuit For VKA > VREF FIGURE 9 — Test Circuit For VKA = VREF VKA Input IOFF FIGURE 11 — Test Circuit For IOFF Copyright © 1999 Rev. 1.0 9/99 7 PRODUCT DATABOOK 1996/1997 LX432 L OW V OLTAGE A DJUSTABLE P RECISION S HUNT R EGULATORS P D R O D U C T I O N A T A S H E E T T Y P I C A L A P P L I C AT I O N VIN 110/220V AC VOUT 3.3V Controller UC384x/LX155x DRV V CC ISENSE GND VFB LX432 FIGURE 12 — LX432 In A Power Supply Isolated Feedback Application 1 2 V 3 .3 V 0 .1 µ F 4 7 0 µ F 0 .1 µ F 5 0 0 9 2 .7 V 1 4 0 9 L X 4 3 2 1 2 0 9 ( e .g . In te l i7 4 0 1 0 0 0 µ F ® c h ip s e t) 0 .1 µ F FIGURE 13 — LX432 In 3.3V To 2.7V Low Dropout Regulator Application PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time. 8 Copyright © 1999 Rev. 1.0 9/99