The LTC4257CDD provides complete signature and power interface functions for a device operating in an IEEE 802.3af Power over Ethernet (PoE) system. The LTC4257CDD simplifies Powered Device (PD) design by incorporating the 25k signature resistor, the classification current source, input current limit with thermal foldback, undervoltage lockout and power good signaling, all in a single 8-pin package. By incorporating a high voltage power MOSFET onboard, the LTC4257CDD provides the system designer with reduced cost while also saving board space.
The LTC4257CDD can interface directly with a variety of ADI's DC/DC converter products to provide a cost effective power solution for IP phones, wireless access points and other PDs. Analog Devices also provides solutions for Power Sourcing Equipment (PSE) applications with quad network power controllers.
The LTC4257CDD is available in the 8-pin SO and low profile (3mm × 3mm) DFN packages.
Feature
- Complete Power Interface Port for IEEE 802.3af® Powered Devices (PDs)
- Onboard 100V, 400mA Power MOSFET
- Precision Input Current Limit
- Onboard 25k Signature Resistor
- Programmable Classification Current (Class 0-4)
- Undervoltage Lockout
- Smart Thermal Protection
- Power Good Signal
- Available in 8-Pin SO and Low Profile (3mm × 3mm) DFN Packages
Applications
- IP Phone Power Management
- Wireless Access Points
- Telecom Power Control
(Picture: Pinout)
