LTC4258 - Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection
Features
- Controls Four Independent -48V Powered Ethernet Ports
- Each Port Includes:
- IEEE 802.3af Compliant PD Detection and Classification
- Output Current Limit with Foldback,Short-Circuit Protection with Fast Gate Pull-Down
- PD Disconnect Using DC Sensing
- Power Good Indication Operates Autonomously or by I2C Control
- 4-Bit Programmable Digital Address Allows Control of Up to 64 Ports
- Programmable INT Pin Eliminates Software Polling
- Current and Duty Cycle Limits Protect External FETs
- Available in a 36-Pin SSOP Package
Typical Application
Description
The LTC4258 is a quad –48V Hot Swap controller designed for use in IEEE 802.3af compliant Power Sourcing Equipment (PSE). It consists of four independent ports, each with output current limit, short-circuit protection, complete Powered Device (PD) detection and classification capability, and programmable PD disconnect using DC sensing. Used with power MOSFETs and passives as in Figure 1, the LTC4258 can implement a complete IEEE 802.3af-compliant PSE.
The LTC4258 can operate autonomously or be controlled by an I2C serial interface. Up to 16 LTC4258s may coexist on the same data bus, allowing up to 64 powered Ethernet ports to be controlled with only two digital lines. Fault conditions are optionally signaled with the INT pin to eliminate software polling.
External power MOSFETs, current sense resistors and diodes allow easy scaling of current and power dissipation levels and provide protection against voltage and current spikes and ESD events.
The LTC4258 is available in a 36-pin SSOP package.
Linear Technology also provides solutions for 802.3af PD applications with the LTC4257, LTC4257-1, and LTC4267.
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 |
|---|---|---|---|---|---|
| LTC4258CGW#PBF | SSOP-36 | GW | C | 05-08-1642 (GW36) | Yes |
| LTC4258CGW#TRPBF | SSOP-36 | GW | C | 05-08-1642 (GW36) | 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 | |
|---|---|---|---|---|---|---|
| LTC4258CGW#PBF | SSOP-36 | C | $8.65 | $6.35 | Yes | |
| LTC4258CGW#TRPBF | SSOP-36 | C | $6.45 | 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.Click here to view our complete list of demo boards
Applications
- IEEE 802.3af Compliant Endpoint and Midspan Power Sources
- IP Phone Systems
- DTE Power Distribution
People Who Viewed This Product Also Viewed
- LTC4263 - Single IEEE 802.3af Compliant PSE Controller with Internal Switch
- LT4275 - LTPoE++/PoE+/PoE PD Controller
- LTC4266 - Quad IEEE 802.3at Power Over Ethernet Controller
- LT4363 - High Voltage Surge Stopper with Current Limit
- LTC4366 - High Voltage Surge Stopper
- LT3748 - 100V Isolated Flyback Controller
- LT3761/LT3761-1 - 60VIN LED Controller with Internal PWM Generator
- LTC4364 - Surge Stopper with Ideal Diode
- LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
- LTC3803 - Constant Frequency Current Mode Flyback DC/DC Controller in ThinSOT
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
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
- LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
- LTpowerCAD - A complete power supply selection, synthesis and design tool
- LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
- PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
- LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
- And More!
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.
