Precision Adjustable Shunt Regulator
Data Sheets OBS (Obsolete)


Information Precision Adjustable Shunt Regulator
Reference Voltage Adjustable, Fixed
VOUT (V) -
VOUT Adj MIN (V) 2.5
VOUT Adj MAX (V) 36
Operating Current (MAX) (mA) 150
Operating Current (MIN) (mA) 1
IQ (µA) 1000
Initial Accuracy (%) 0.50
IREF (µA) 0.7
Temperature Coefficient (ppm/°C) 30
Temperature Range (°C) -40 to 125
Package SOT89-3
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The SPX431A is a three-terminal adjustable shunt voltage regulator providing a highly accurate bandgap reference.

The SPX431A acts as an open-loop error amplifier with a 2.5V temperature compensation reference. The SPX431A has thermal stability, wide operating current of 150mA and broad temperature range of -40°C to 125°C, making it suitable for a variety of applications which require a low-cost, high performance solution. The SPX431A tolerance of 0.5% is proven to be sufficient to overcome all other errors in the system to virtually eliminate the need for trimming in the power supply manufacturer's assembly line and contribute a significant cost savings. The output voltage may be adjusted to any value between VREF and 36 volts with two external resistors.

The SPX431A is available in RoHS compliant, lead free TO-92 and SOT-89 packages.

  • 0.5% precise output voltage
    • Adjustable up to 36V
  • Wide operating current
    • 1mA to 150mA
  • Low temperature coefficient at 30ppm/°C
  • Extended temperature range
    • -40°C to 125°C
  • Improved replacment for TL431
  • RoHS compliant, lead free TO-92 and SOT-89 packages

  • Charger
  • Switching power supplies
  • Graphics card
  • Monitors, VCR, TV

Documentation & Design Tools

Type Title Version Date File Size
Data Sheets SPX431A Precision Adjustable Shunt Regulator 2.0.1 November 2022 954.9 KB
Application Notes AN200, Downloading and Installing CAD Symbols and Footprints with Ultra Librarian April 2019 1.2 MB
Product Brochures Power Management Brochure October 2020 2.4 MB
Symbols & Footprints SPX431AM1-L/TR CAD File (.bxl) September 2018 27.8 KB
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Quality & RoHS

Part Number RoHS | Exempt RoHS Halogen Free REACH TSCA MSL Rating / Peak Reflow Package
SPX431AM1-L/TR N Y Y Y Y L3 / 260ᵒC SOT-89

Click on the links above to download the Certificate of Non-Use of Hazardous Substances.

Additional Quality Documentation may be available, please Contact Support.

Parts & Purchasing

Part Number Pkg Code Min Temp Max Temp Status Suggested Replacement PDN
SPX431AM1-L/TR SOT-89-3 -40 125 OBS SPX1431M1-L/TR
SPX431AN-L/TR TO-92-3 -40 125 OBS SPX431AM1-L/TR
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Part Status Legend
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs.


Pkg Code Details Quantities Dimensions PDF
  • JEDEC Reference: TO-243
  • MSL Pb-Free: L2 @ 260ºC
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 107.1ºC/W
  • Bulk Pack Style: Canister
  • Quantity per Bulk Pack: n/a
  • Quantity per Reel: 2500
  • Quantity per Tube: n/a
  • Quantity per Tray: n/a
  • Reel Size (Dia. x Width x Pitch): 330 x 12 x 8
  • Tape & Reel Unit Orientation: Tab at sprocket hole.
  • Dimensions: mm
  • Length: 4.60 max
  • Width: 2.60 max
  • Thickness: 1.60
  • Lead Pitch: 1.50
  • JEDEC Reference: n/a
  • MSL Pb-Free: n/a
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 131.9ºC/W
  • Bulk Pack Style: Ammo
  • Quantity per Bulk Pack: n/a
  • Quantity per Reel: 2000
  • Quantity per Tube: n/a
  • Quantity per Tray: n/a
  • Reel Size (Dia. x Width x Pitch): Ammo
  • Tape & Reel Unit Orientation: Ammopack
  • Dimensions: inch
  • Length: 0.195 max
  • Width: 0.195 max
  • Thickness: 0.155 max
  • Lead Pitch: 0.055


Distribution Date Description File
03/29/2022 Product Discontinuation Notice
07/11/2017 Product Discontinuation Notification
02/19/2016 Material change. Qualified copper wire bonding assembly.
05/22/2013 Addition of JCET as an alternate qualified assembly and test location. Process & material change.
05/07/2013 Addition of alternate Assembly and Test Site JCET (Chuzhou). Process change.
08/07/2009 Notice of Obsolescence – Selected Power Management Parts Discontinued due to low market demand, effective immediately.
09/10/2008 Notice of Obsolescence –Selected Power Management Parts This is notification that the Power Management products listed on the attached page have been discontinued by Exar Corporation due to low market demand, effective immediately.
02/28/2007 Product Obsolescence Letter and Discontinuation Notification. Discontinued.
02/02/2006 Announcing transfer of certain Power Management and Interface Products from Hillview fabrication facility to wafer foundary BCD. See attached Product List Power Management and Interface products as listed are being transfer to external wafer foundry, due to cessation of operations of the sipex Hillview Fabrication manufacturing site

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