LTC4257-1
Info : RECOMMENDED FOR NEW DESIGNS
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LTC4257-1

IEEE 802.3af PD Power over Ethernet Interface Controller with Dual Current Limit

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Info : RECOMMENDED FOR NEW DESIGNS tooltip
Info : RECOMMENDED FOR NEW DESIGNS tooltip
Part Details
Part Models 8
1ku List Price Starting From $1.29
Features
  • 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
Additional Details
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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
Part Models 8
1ku List Price Starting From $1.29

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Documentation

Documentation

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Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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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

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LTC4257IS8-1#TRPBF

PRODUCTION

Jun 16, 2021

- 21_0026

Laser Top Mark for 8SOICN Assembled in ADPG, UTL and CRM

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Filter by Model

reset

Reset Filters

Part Models

Product Lifecycle

PCN

Dec 14, 2023

- 22_0255

arrow down

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

arrow down

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

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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DC671A

LTC4257CS8-1 | Power-Over-Ethernet Interface Controller, Vsig = 48V, VOUT = 3.3V

Tools & Simulations

Tools & Simulations 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.

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