LT1431 - Programmable Reference
Features
- Guaranteed 0.4% Initial Voltage Tolerance
- 0.1Ω Typical Dynamic Output Impedance
- Fast Turn-On
- Sink Current Capability, 1mA to 100mA
- Low Reference Pin Current
- Available in J8, N8, S8 or 3-Lead TO-92 Z Packages
Typical Application
Description
The LT1431 is an adjustable shunt voltage regulator with 100mA sink capability, 0.4% initial reference voltage tolerance and 0.3% typical temperature stability. On-chip divider resistors allow the LT1431 to be configured as a 5V shunt regulator, with 1% initial voltage tolerance and requiring no additional external components. By adding two external resistors, the output voltage may be set to any value between 2.5V and 36V. The nominal internal current limit of 100mA may be decreased by including one external resistor.
A simplified 3-pin version, the LT1431CZ/LT1431IZ, is available for applications as an adjustable reference and is pin compatible with the TL431.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LT1431CN8#PBF | N-8 | N | C | 05-08-1510 (N8) | Yes |
| LT1431CS8#PBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1431CS8#TRPBF | SO-8 | S8 | C | 05-08-1610 (S8) | Yes |
| LT1431CZ#PBF | TO-92 | Z | C | 05-08-1410 | Yes |
| LT1431CZ#TRPBF | TO-92 | Z | C | 05-08-1410 | Yes |
| LT1431IN8#PBF | N-8 | N | I | 05-08-1510 (N8) | Yes |
| LT1431IS8#PBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LT1431IS8#TRPBF | SO-8 | S8 | I | 05-08-1610 (S8) | Yes |
| LT1431IZ#PBF | TO-92 | Z | I | 05-08-1410 | Yes |
| LT1431IZ#TRPBF | TO-92 | Z | I | 05-08-1410 | Yes |
| LT1431MJ8 | CERDIP-8 | J | M | 05-08-1110 (J8) | No |
| LT1431MJ8#PBF | CERDIP-8 | J | M | 05-08-1110 (J8) | Yes |
| LT1431MPS8#PBF | SO-8 | S8 | MP | 05-08-1610 (S8) | Yes |
| LT1431MPS8#TR | SO-8 | S8 | MP | 05-08-1610 (S8) | No |
| LT1431MPS8#TRPBF | SO-8 | S8 | MP | 05-08-1610 (S8) | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT1431CN8#PBF | N-8 | C | $1.50 | $1.20 | Yes | |
| LT1431CS8#PBF | SO-8 | C | $2.08 | $1.75 | Yes | |
| LT1431CS8#TRPBF | SO-8 | C | $1.81 | Yes | ||
| LT1431CZ#PBF | TO-92 | C | $1.35 | $1.05 | Yes | |
| LT1431CZ#TRPBF | TO-92 | C | $1.11 | Yes | ||
| LT1431IN8#PBF | N-8 | I | $1.92 | $1.55 | Yes | |
| LT1431IS8#PBF | SO-8 | I | $2.67 | $2.20 | Yes | |
| LT1431IS8#TRPBF | SO-8 | I | $2.26 | Yes | ||
| LT1431IZ#PBF | TO-92 | I | $1.42 | $1.11 | Yes | |
| LT1431IZ#TRPBF | TO-92 | I | $1.17 | Yes | ||
| LT1431MJ8 | CERDIP-8 | M | $44.98 | $32.50 | No | |
| LT1431MJ8#PBF | CERDIP-8 | M | $44.98 | $32.50 | Yes | |
| LT1431MPS8#PBF | SO-8 | MP | $9.27 | $6.49 | Yes | |
| LT1431MPS8#TR | SO-8 | MP | $6.55 | No | ||
| LT1431MPS8#TRPBF | SO-8 | MP | $6.55 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC259A | LT1339, LTC1693, LT1431 Isolated Demo Board | Telecom Module, 36 to 72Vin, 5V or 3.3Vout @ 10A | Contact Factory | |
| Buy Now | |||
Applications
- Linear Regulators
- Adjustable Power Supplies
- Switching Power Supplies
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
To launch a ready to run LTspice demonstration circuit for this part:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- LT1431 Demo Circuit - 5V Power Supply Monitor with ±500mV Window and 50mV Hysteresis
- LT8310/LT1431 Demo Circuit - 72 Watt Isolated Nonsynchronous Forward Converter with Opto Feedback (36-72V to 12V @ 6A)
- LT8310/LT1431 Demo Circuit - 81 Watt Isolated Nonsynchronous Forward Converter with Opto Feedback (10.8-26.4V to 54V @ 1.5A)
- LTC3723-1/LT1431 Demo Circuit - 130W High Efficiency Isolated Non-Synchronous Push-Pull Converter (34-38V to 50V @ 2.6A)
- LT3753/LT1431 Demo Circuit - 80W Active Clamp Non-Synchronous Forword Converter for PoE
- LT8310/LT1431 Demo Circuit - 92W Isolated Nonsynchronous Forward Converter with Opto Feedback (43-53V to 54V @ 1.7A)
- Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Models for the following parts are available in LTspice:
LT1431
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
