Overview
The LT4293IDD#PBF, produced by Analog Devices Inc., is an LTPoE++/IEEE 802.3af/at/bt-compliant powered device (PD) interface controller. This device is designed to control a low RDS(ON) N-channel MOSFET, maximizing efficiency and delivered power in Power over Ethernet (PoE) applications. The LT4293 supports both single-signature and dual-signature PD topologies, primarily targeting single-signature PDs to simplify the design and eliminate the need for a second PD controller.
Key Specifications
| Parameter | Description |
|---|---|
| Compliance | LTPoE++/IEEE 802.3af/at/bt |
| Package Type | 10-Lead (3mm × 3mm) Plastic DFN |
| Operating Temperature | –40°C to 125°C |
| Signature Resistor | 24.4kΩ (temperature-compensated) |
| Power Classes | Supports IEEE 802.3bt PD classes and types (up to 90W) |
| MOSFET Control | Controls low RDS(ON) N-channel MOSFET |
| Power Good Output | Onboard power good output |
| Ideal Bridge Support | Supports LT4320/LT4321 ideal bridges |
Key Features
- Distinguishes between LTPoE++ and IEEE 802.3bt power sourcing equipment (PSE) during mutual identification and negotiation of available power.
- Utilizes an external, low RDS(ON), N-channel, hot swap MOSFET to maximize efficiency and delivered power.
- Includes onboard signature resistor and power good output.
- Supports single-signature and dual-signature PD topologies, primarily targeting single-signature PDs.
- Compatible with LT4320/LT4321 ideal bridges to extend end-to-end power delivery efficiency and eliminate costly heat sinks.
Applications
- Power over Ethernet (PoE) systems, including LTPoE++ and IEEE 802.3af/at/bt compliant devices.
- Network devices such as switches, routers, and access points.
- IP phones, security cameras, and other PoE-enabled devices.
- Industrial automation and control systems requiring reliable and efficient power delivery.
Q & A
- What is the primary function of the LT4293IDD#PBF?
The LT4293IDD#PBF is an LTPoE++/IEEE 802.3af/at/bt-compliant powered device (PD) interface controller designed to control a low RDS(ON) N-channel MOSFET for efficient power delivery in PoE applications.
- What types of PD topologies does the LT4293 support?
The LT4293 supports both single-signature and dual-signature PD topologies, primarily targeting single-signature PDs.
- What is the significance of the onboard signature resistor?
The onboard signature resistor (24.4kΩ) allows the power sourcing equipment (PSE) to recognize the presence of a PD and request power to be applied.
- How does the LT4293 distinguish between LTPoE++ and IEEE 802.3bt PSE?
The LT4293 uses its T2P output to distinguish between LTPoE++ and IEEE 802.3bt power sourcing equipment during mutual identification and negotiation of available power.
- What is the operating temperature range of the LT4293IDD#PBF?
The operating temperature range is –40°C to 125°C.
- What types of packages are available for the LT4293IDD#PBF?
The device is available in a 10-Lead (3mm × 3mm) Plastic DFN package.
- Does the LT4293 support ideal bridges?
Yes, it supports LT4320/LT4321 ideal bridges to enhance power delivery efficiency and eliminate costly heat sinks.
- What are some common applications for the LT4293IDD#PBF?
Common applications include PoE systems, network devices, IP phones, security cameras, and industrial automation systems.
- How does the LT4293 handle power classification?
The LT4293 handles power classification by setting the RCLS and RCLS++ resistor values, supporting IEEE 802.3bt PD classes and types up to 90W.
- What is the purpose of the power good output on the LT4293?
The power good output indicates when the power is stable and within the specified range, allowing the system to safely operate.
