SI3402-B-GMR

Incorporates switcher EMI reduction techniques. Supports non-isolated and isolated switching topologies. Comprehensive protection circuitry. - Transient overvoltage protection - Undervoltage lockout - Early power-loss indicator - Thermal shutdown protection - Foldback current limiting - Low-profile 5×5 mm 20-pin QFN - RoHS-compliant The Si3402 integrates all power management and control functions required in a Power-over-Ethernet (PoE) powered device (PD) application. The Si3402 converts the high voltage supplied over the 10/100/1000BASE-T Ethernet connection into a regulated, low-voltage output supply. The optimized architecture of the Si3402 minimizes the solution footprint, reduces external BOM cost, and enables the use of low-cost external components while maintaining high performance. The Si3402 integrates the required diode bridges and transient surge suppressor, thus enabling direct connection of the IC to the Ethernet RJ-45 connector. The switching power FET and all associated functions are also integrated. The integrated switching regulator supports isolated (flyback) and non-isolated (buck) converter topologies. The Si3402 supports IEEE 802.3 Type 1 (Class 3 and below) Powered Device applications. Standard external resistors connected to the Si3402 provide the proper IEEE 802.3 signatures for the detection function and programming of the requested power class. Startup circuits ensure well-controlled initial operation of both the hotswap switch and the voltage regulator. The Si3402 is available in a low-profile, 20-pin, 5×5 mm QFN package. The Si3402-B is a pin-compatible replacement of the obsolete Si3402-A. PCB layouts designed for Si3402-A can be reused with Si3402-B, but some component value changes are required.

Applications

• Voice over IP telephones and adapters
• Wireless access points
• Security cameras
• Point-of-sale terminals
• Internet appliances
• Network devices
• High power applications

Key features

• Pin-compatible replacement for the obsolete Si3402-A
• IEEE 802.3 standard-compliant solution, including pre-standard (legacy) PoE support
• Highly-integrated IC enables compact solution footprints
• Minimal external components
• Integrated diode bridges and transient surge suppressor
• Integrated switching regulator controller with on-chip power FET
• Integrated dual current-limited hotswap switch
• Programmable classification circuit