Overview
The LT4321HUF#PBF, produced by Analog Devices Inc., is a dual ideal diode bridge controller designed to enhance the efficiency and reliability of Power over Ethernet (PoE) powered devices. This controller enables the device to receive power in either voltage polarity from RJ-45 data pairs, spare pairs, or both, making it versatile for various PoE applications. The LT4321 replaces traditional diode bridge rectifiers with low-loss N-channel MOSFET bridges, significantly reducing thermal design issues and increasing the delivered power.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Operating Supply Range | |IN12 – IN36|, |IN45 – IN78|, OUTP | 20 | 80 | V | |
| Undervoltage Lockout (VUVLO) | OUTP – OUTN | 15 | 17 | 18 | V |
| Total Supply Current in Detect Region (IS(DET)) | < 800 | μA | |||
| Operating Ambient Temperature Range | -40°C | 125°C | |||
| Storage Temperature Range | -65°C | 150°C | |||
| Absolute Maximum Voltage | OUTP – OUTN | -0.3V | 100V | ||
| Package Type | 16-Lead 4mm × 4mm Plastic QFN |
Key Features
- Replaces traditional diode bridge rectifiers with low-loss N-channel MOSFET bridges to increase power efficiency and reduce thermal issues.
- Works with both 2-pair and 4-pair PoE applications.
- High impedance input sense pins prevent reverse current on unused pairs.
- Fast turn-off minimizes reverse current transients in case of power source failure or shorting.
- Internal charge pump allows an all-NMOS bridge, eliminating the need for larger and more costly PMOS switches.
- Fully compatible with IEEE 802.3 detection and classification.
- Supports PoE, PoE+, and LTPoE++ standards.
- Low quiescent operating current of less than 800 μA.
- Available in H-grade version operating up to 125°C.
Applications
The LT4321HUF#PBF is ideal for various Power over Ethernet (PoE) applications, including:
- PoE powered devices (PDs) requiring efficient power delivery.
- IEEE 802.3af, 802.3at, and 802.3bt compliant systems.
- Network devices such as IP phones, wireless access points, and security cameras.
- Industrial control systems and IoT devices.
Q & A
- What is the primary function of the LT4321HUF#PBF?
The LT4321HUF#PBF is a dual ideal diode bridge controller designed to enable PoE powered devices to receive power efficiently from RJ-45 data pairs or spare pairs.
- What are the key benefits of using the LT4321HUF#PBF over traditional diode bridge rectifiers?
The LT4321HUF#PBF reduces thermal design issues, increases delivered power, and operates with low-loss N-channel MOSFET bridges.
- Is the LT4321HUF#PBF compatible with different PoE standards?
Yes, it supports PoE, PoE+, and LTPoE++ standards and is fully compatible with IEEE 802.3 detection and classification.
- What is the operating temperature range of the LT4321HUF#PBF?
The operating ambient temperature range is -40°C to 125°C, with an H-grade version available for higher temperature applications.
- How does the LT4321HUF#PBF handle power source failures or shorts?
The LT4321HUF#PBF features a fast turn-off mechanism that minimizes reverse current transients in case of power source failure or shorting.
- What is the quiescent operating current of the LT4321HUF#PBF?
The quiescent operating current is less than 800 μA.
- What type of package does the LT4321HUF#PBF come in?
The LT4321HUF#PBF comes in a 16-Lead 4mm × 4mm Plastic QFN package.
- How does the internal charge pump benefit the LT4321HUF#PBF?
The internal charge pump allows for an all-NMOS bridge, eliminating the need for larger and more costly PMOS switches.
- What are some common applications for the LT4321HUF#PBF?
Common applications include PoE powered devices, IEEE 802.3af, 802.3at, and 802.3bt compliant systems, network devices, and industrial control systems.
- Where can I purchase the LT4321HUF#PBF?
The LT4321HUF#PBF can be purchased from various electronic component distributors such as X-ON Electronics, Mouser, and directly from Analog Devices.
