LTC4257-1
PRODUCTIONIEEE 802.3af PD Power over Ethernet Interface Controller with Dual Current Limit
- Part Models
- 8
- 1ku List Price
- Starting From $1.63
Overview
- Complete Power Interface Port for IEEE 802®.3af Powered Devices (PDs)
- Onboard 100V, 400mA Power MOSFET
- Precision Dual Level Current Limit
- Onboard 25k Signature Resistor with Disable
- Programmable Classification Current (Class 0-4)
- Undervoltage Lockout
- Thermal Overload Protection
- Power Good Signal
- Available in 8-Pin SO and Low Profile (3mm x 3mm) DFN Packages
The LTC4257-1 provides complete signature and power interface functions for a device operating in an IEEE 802.3af Power over Ethernet (PoE) system. The LTC4257-1 simplifies Powered Device (PD) design by incorporating the 25k signature resistor, classification current source, input current limit, undervoltage lockout, thermal overload protection, signature disable and power good signalling, all in a single 8-pin package. The LTC4257-1 includes a precision, dual level current limit circuit. This allows it to charge large load capacitors and interface with legacy Power over Ethernet systems while maintaining compatibility with the current IEEE 802.3af specification. By incorporating a high voltage power MOSFET onboard, the LTC4257-1 provides the system designer with reduced cost while also saving board space.
The LTC4257-1 can interface directly with a variety of ADI DC/DC converter products to provide a cost effective power solution for IP phones, wireless access points and other PDs. Analog Devices also provides network power controllers for Power Sourcing Equipment (PSE) applications.
The LTC4257-1 is available in the 8-pin SO and low profile (3mm x 3mm) DFN packages.
Applications
- IP Phone Power Management
- Wireless Access Points
- Telecom Power Control
Documentation
Data Sheet 1
User Guide 1
Video 1
Product Selector Card 2
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LTC4257CDD-1#PBF | 8-Lead DFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC4257CDD-1#TRPBF | 8-Lead DFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC4257CS8-1#PBF | 8-Lead SOIC (Narrow 0.15 Inch) | ||
| LTC4257CS8-1#TRPBF | 8-Lead SOIC (Narrow 0.15 Inch) | ||
| LTC4257IDD-1#PBF | 8-Lead DFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC4257IDD-1#TRPBF | 8-Lead DFN (3mm x 3mm x 0.75mm w/ EP) | ||
| LTC4257IS8-1#PBF | 8-Lead SOIC (Narrow 0.15 Inch) | ||
| LTC4257IS8-1#TRPBF | 8-Lead SOIC (Narrow 0.15 Inch) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Dec 14, 2023 - 22_0255 Epoxy Change from Henkel 8290 to 8290A for 8-Lead SOIC Package (PCN part 2 of 2) |
||
| LTC4257CS8-1#PBF | PRODUCTION | |
| LTC4257CS8-1#TRPBF | PRODUCTION | |
| LTC4257IS8-1#PBF | PRODUCTION | |
| LTC4257IS8-1#TRPBF | PRODUCTION | |
|
Jun 16, 2021 - 21_0026 Laser Top Mark for 8SOICN Assembled in ADPG, UTL and CRM |
||
| LTC4257CS8-1#PBF | PRODUCTION | |
| LTC4257CS8-1#TRPBF | PRODUCTION | |
| LTC4257IS8-1#PBF | PRODUCTION | |
| LTC4257IS8-1#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Can't find the software or driver you need?
Request a Driver/SoftwareHardware Ecosystem
Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LTC4257
- LTC4257-1
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Evaluation Kits
LTC4257CS8-1 | Power-Over-Ethernet Interface Controller, Vsig = 48V, VOUT = 3.3V
Resources
Latest Discussions
No discussions on LTC4257-1 yet. Have something to say?
Start a Discussion on EngineerZone®