Overview
The LTC4279IUFD#PBF, produced by Analog Devices Inc., is an autonomous single port power sourcing equipment (PSE) controller. It is designed for use in IEEE 802.3at Type 1, Type 2, and LTPoE++ compliant Power over Ethernet (PoE) systems. This controller operates fully autonomously without the need for a microcontroller, simplifying the implementation of PSE in various applications. The LTC4279 is known for its low heat dissipation, achieved through the use of a low-RDS(ON) external MOSFET and optimized design.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Main PoE Supply Voltage (VEE) | AGND – VEE | 45 | 51 | 57 | V |
| Main PoE Supply Voltage (VEE) for IEEE Type 2, DUALPD, LTPoE++ | AGND – VEE | 51 | 57 | 57 | V |
| Main PoE Supply Voltage (VEE) for LTPoE++ 70W and LTPoE++ 90W | AGND – VEE | 57 | 65 | 65 | V |
| Power-On Delay | From end of valid detect to application of power to port | 82 | ms | ||
| Turn-On Rise Time | 10% to 90% of (AGND – VEE), CPORT = 0.15µF | 15 | 24 | µs | |
| Turn-On Ramp Rate | CPORT = 0.15µF | 10 | V/µs | ||
| Maximum Junction Temperature (TJMAX) | 125 | °C | |||
| Thermal Resistance (θJA) | For QFN-20 package | 43 | °C/W |
Key Features
- Autonomous operation without a microcontroller, simplifying PSE implementation.
- Compliance with IEEE 802.3at Type 1, Type 2, and LTPoE++ standards.
- Low heat dissipation using a low-RDS(ON) external MOSFET.
- Cable drop compensation to ensure consistent power delivery.
- Support for dual-signature PDs in DUALPD mode.
- Configurable maximum power delivery via the PWRMODE pin.
- Available in 20-lead QFN (4mm × 5mm) package with exposed pad.
Applications
- Power over Ethernet (PoE) systems, including IEEE 802.3at Type 1, Type 2, and LTPoE++ compliant devices.
- Network infrastructure equipment such as switches, routers, and access points.
- IP phones, wireless access points, and other PoE-powered devices.
- Industrial and commercial automation systems requiring PoE power delivery.
Q & A
- What is the LTC4279IUFD#PBF used for?
The LTC4279IUFD#PBF is used as a single port power sourcing equipment (PSE) controller in IEEE 802.3at Type 1, Type 2, and LTPoE++ compliant Power over Ethernet (PoE) systems.
- Does the LTC4279 require a microcontroller for operation?
No, the LTC4279 operates autonomously without the need for a microcontroller.
- What are the main supply voltage ranges for the LTC4279?
The main PoE supply voltage (VEE) ranges from 45V to 57V for IEEE Type 1, and up to 65V for LTPoE++ 70W and 90W configurations.
- What is the thermal resistance (θJA) of the QFN-20 package?
The thermal resistance (θJA) for the QFN-20 package is 43°C/W.
- Does the LTC4279 support dual-signature PDs?
- How is the maximum power delivery configured on the LTC4279?
The maximum power delivery is configured via the PWRMODE pin using a single resistor connected to VEE.
- What is the typical turn-on rise time for the LTC4279?
The typical turn-on rise time is 24 µs for a 10% to 90% rise of (AGND – VEE) with CPORT = 0.15µF.
- What is the maximum junction temperature (TJMAX) for the LTC4279?
The maximum junction temperature (TJMAX) is 125°C.
- In what package is the LTC4279IUFD#PBF available?
The LTC4279IUFD#PBF is available in a 20-lead QFN (4mm × 5mm) package with an exposed pad.
- What are some common applications of the LTC4279?
