LT8631 - 100V, 1A Synchronous Micropower Step-Down Regulator
Features
- Ultrawide Input Voltage Range: 3V to 100V
- Output Voltage Range: 0.8V to 60V
- Internal Synchronous Switches
- Low Ripple Burst Mode® Operation:
16μA IQ at 12VIN to 5VOUT Output Ripple <10mVP-P
7μA IQ at 48VIN to 5VOUT Output Ripple <10mVP-P - Low Dropout: 99% Maximum Duty Cycle
- Peak Current Mode Control
- Fixed Frequency Operation: 100kHz to 1MHz
- Synchronization Input
- Programmable Undervoltage Lockout
- Power Good Flag
- Flexible Output Voltage Tracking
- Short-Circuit Protection
- Low Shutdown Current: 5μA
- Tolerates Pin Open/Short Faults
- Thermally Enhanced 20-Lead TSSOP with High Voltage Lead Spacing
AEC-Q100 data available for specific packages
Typical Application
Description
The LT®8631 is a current mode PWM step-down DC/DC converter with internal synchronous switches that provide current for output loads up to 1A. The wide input range of 3V to 100V makes the LT8631 suitable for regulating power from a wide variety of sources, including automotive and industrial systems and 36V to 72V telecom supplies. Low ripple Burst Mode operation enables high efficiency operation down to very low output currents while keeping the output ripple below 10mVP-P. Resistor programmable 100kHz to 1MHz frequency range and synchronization capability enable optimization between efficiency and external component size. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, while also providing output tracking. A power good flag signals when the output voltage is within ±7.5% of the regulated output. Undervoltage lockout can be programmed using the EN/UV pin. Shutdown mode reduces the total quiescent current to < 5μA. The LT8631 is available in a 20-lead TSSOP package with exposed pad for low thermal resistance and high voltage lead spacing.
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 |
|---|---|---|---|---|---|
| LT8631EFE#PBF | TSSOP-20 | FE | E | 05-08-1924 | Yes |
| LT8631EFE#TRPBF | TSSOP-20 | FE | E | 05-08-1924 | Yes |
| LT8631HFE#PBF | TSSOP-20 | FE | H | 05-08-1924 | Yes |
| LT8631HFE#TRPBF | TSSOP-20 | FE | H | 05-08-1924 | Yes |
| LT8631IFE#PBF | TSSOP-20 | FE | I | 05-08-1924 | Yes |
| LT8631IFE#TRPBF | TSSOP-20 | FE | I | 05-08-1924 | 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 | |
|---|---|---|---|---|---|---|
| LT8631EFE#PBF | TSSOP-20 | E | $5.14 | $3.60 | Yes | |
| LT8631EFE#TRPBF | TSSOP-20 | E | $3.66 | Yes | ||
| LT8631HFE#PBF | TSSOP-20 | H | $6.02 | $4.21 | Yes | |
| LT8631HFE#TRPBF | TSSOP-20 | H | $4.27 | Yes | ||
| LT8631IFE#PBF | TSSOP-20 | I | $5.66 | $3.96 | Yes | |
| LT8631IFE#TRPBF | TSSOP-20 | I | $4.02 | 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 |
|---|---|---|---|
| DC2110A | LT8631EFE Demo Board | Sync Buck, 6.5V ≤ VIN ≤ 100V; VOUT = 5V @ 1A | $150.00 | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT8631HFE#PBF | TSSOP-20 | H | $6.02 | $4.21 | Yes | |
| LT8631HFE#TRPBF | TSSOP-20 | H | $4.27 | Yes | ||
| LT8631IFE#PBF | TSSOP-20 | I | $5.66 | $3.96 | Yes | |
| LT8631IFE#TRPBF | TSSOP-20 | I | $4.02 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Automotive Supplies
- Telecom Supplies
- Distributed Supply Regulation
People Who Viewed This Product Also Viewed
- LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
- LT8620 - 65V, 2A Synchronous Step-Down Regulator with 2.5μA Quiescent Current
- LT8471 - Dual Multitopology DC/DC Converters with 2A Switches and Synchronization
- LT4320/LT4320-1 - Ideal Diode Bridge Controller
- LT4363 - High Voltage Surge Stopper with Current Limit
- LTC4364 - Surge Stopper with Ideal Diode
- LTC3637 - 76V, 1A Step-Down Regulator
- LT8614 - 42V, 4A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current
- LTC7138 - High Efficiency, 140V 400mA Step-Down Regulator
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
Product Notifications
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.
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
- 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:
LT8631
LTpowerCAD
The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD
To open the project file for this circuit:
- Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
- Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file
- Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu
Design tools for the following parts are available in LTpowerCAD:
LT8631
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.
