RT7402

  30W POE PD Module ( Isolation Model)

Product Description

© 2014 Shenzhen Ring&tone  Electronic Technology Co., Ltd. All rights reserved.

This document contains proprietary information of ring&tone and is not to be disclosed or used without the prior written permission of ring&tone.

Due to update and improvement of ring&tone products and technologies, information in this document is subjected to change without notice.

Features：

• IEEE802.3at and IEEE802.3af compliant
• Maximum 30W output power
• Input voltage range 36V to 57V
• Integral high efficiency DC/DC converter.
• Low output ripple and noise
• High performance with low price
• Short-circuit protection
• Transformer isolation ,1000V isolation (input to output)
• Easy to use, with a minimum number of external components.
• IEC 61000-4-2 Level 4 (8KV/15KV) ESD protection
• IEC 61000-4-5 Level 3 SURGE LEVEL :10/700μs 40ohm 4KV---Optional

Applications：

• IP Cameras
• Wireless access point
• Security and alarm systems
• VOIP telephone
• Point of sale network terminal equipment

Description：

The RT7402 series of modules are designed to extract power from a conventional

twisted pair Category 5 Ethernet cable, conforming to the IEEE 802.3af and IEEE 802.3at    Power-over-Ethernet(PoE) standard.

The RT7402 signature and control circuit provides the PoE compatibility signature and

power classification required by the Power Sourcing Equipment (PSE) before applying up

to 30W power to the port.

The DC/DC converter operates over a wide input voltage range and provides a regulated

output. The DC/DC converter also has built-in short-circuit output protection.

• RT7402 Product Selector

*At 25°C with VIN = 48V

** Maximum Output Power: means it not could be operated in continuous stage .only short-term of Boot up/Heavy loading

• Pin Description:

• Absolute Maximum Ratings

Note 1: Exceeding the above ratings may cause permanent damage to the product. Functional operation under these conditions is not implied. Maximum ratings assume free airflow.

• Recommended Operating Conditions

Note 1: With minimum load

     2: See Section Operating Temperature Range

      ** Extended use close to, or at the maximum operating temperature can reduce the life time of the device.

• DC Electrical Characteristics

Note 1: Typical figures are at 25°C with a nominal 48V supply and are for design aid only. Not Guaranteed

     2: The output ripple and noise can be reduced with an external filter, see application note.

     3: Continuous short circuit duration is applicable at 25'C ambient temperature in free air. At higher temperatures or with restricted

        airflow (e.g. in a sealed enclosure) the duration will need to be limited to avoid overheating.

• RT7402 Typical Connection Diagram:
• 
• RT7402S Typical Connection Diagram:
• 
• • Power Classification

  The RT7402 classification is fixed at Class 4, this means that an IEEE802.3at Type 1 or an IEEE802.3af PSE will default to Class 0. However an IEEE802.3at PSE will recognise the Class 4 as a Type 2 PD.

   

  • AT Detection

  AT-DET output pin which is used to detect a Two Event Physical Layer classification as described in IEEE802.3at. If required the AT-DET pin can be connected directly to an opto-coupler.

  If the detects a Two Event Physical Layer classification, the (AT True) switch will close and Opto1 will turn ON. Opto1 will be connected across the isolation barrier and the output collector can be connected to a controller (with a pull-up resistor connected to the controller’s power rail). When Opto1 is ON the collector (output) will be Logic 0, the controller will then know that the PSE is capable of delivering over 15.4W. To complete the protocol the controller should then confirm that it is a Type 2 PD over the Data Link Layer*.

   If the detects a Single Event Physical Layer classification, Opto1 will be OFF and the output collector will be Logic 1 (via pull-up resistor). The controller should then assume that the PSE is limited to delivering up to 15.4W.

  If the PSE does not support the Physical Layer classification, Opto1 will be OFF. The RT7402 will operate with non IEEE802.3at compliant POE+ PSE’s.

  *Note: There are several PSEs (including Cisco) that will only delivery ≤15.4W until they receive Type 2 PD confirmation, over the Data Link Layer.