RT7640

The RT7640 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 RT7640 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.

    

Related products

 
 

RT7640

   POE PD Module ( Isolation Model)

Product Description

 

Version

Date

Author

Approved By

Remarks

V5.4

2016/4/5

LI xiao yan

Rock

 

V5.6

2017/3/8

LI xiao yan

Rock

 

V5.7

2018/3/8

LI xiao yan

Rock

 

 

 

 

 

 

© 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 ,1500V isolation (input to output)
  • Easy to use, with a minimum number of external components.

 

Applications

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

 

 

Description

The RT7640 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 RT7640 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.

    

  • RT7640 Product Selector

 

Part Number

Nominal Output

Maximum Output Power*

 

AT-DET putout

Marking

Package

RT7640-12V

12V

30W

YES

RT7640

DIP

RT7640-5V

5V

25W

YES

RT7640

DIP

 

*At 25°C with VIN = 52V

 

  • Pin Description:

Pin #

Name

Description

1

VA1

RX Input (1). This input pin is used in conjunction with VA2 and

connects to the centre tap of the transformer connected to pins 1

& 2 of the RJ45 connector (RX) - it is not polarity sensitive.

2

VA2

TX Input (2). This input pin is used in conjunction with VA1 and

connects to the centre tap of the transformer connected to pins 3

& 6 of the RJ45 connector (TX) - it is not polarity sensitive.

3

VB1

Direct Input (1). This input pin is used in conjunction with VB2 and connects to pin 4 & 5 of the RJ45 connector - it is not polarity

sensitive.

4

VB2

Direct Input (2). This input pin is used in conjunction with VB1 and connects to pin 7 & 8 of the RJ45 connector - it is not polarity

sensitive.

5

AT-DET+

Internal rectifier bridge output +  

6

AT-DET-

AT Detect Output. This pin indicates if an IEEE802.3at PSE is supplying power to the RT7640.   

7

CAP-

connect cap-,Internal GND, Do not connect other circuits

8

-VDC

 

DC Return. This pin is the return path for the +VDC output.

9

10

+VDC

DC Output. This pin provides the regulated output from the DC/DC converter.

11

 

 

 

  • Absolute Maximum Ratings

 

Parameter

Symbol

Min

Max

Units

1

DC Supply Voltage

VCC

-0.3

60

V

2

DC Supply Voltage Surge for 1ms

VSURGE

-0.6

80

V

3

Storage Temperature

TS

-40

100

OC

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

 

Parameter

Symbol

Min

Typ

Max

Units

1

Input Supply Voltage1

VIN

36

54

57

V

2

Under Voltage Lockout

VLOCK

30

 

36

V

3

Operating Temperature2

TOP

-20

25

70

Ta / OC

 

 

4

Operating Temperature

30W Continuous

24W Continuous

14W Continuous

 

 

TOP

 

 

 

-20

 

 

 

25

 

50

70

85

 

 

 

Ta / °C

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

 

DC Characteristic

Sym

Min

Typ1

Max

Units

Test Comments

1

Nominal Output Voltage

+VDC

11.5

12.0

12.5

V

RT7640-12V

 

Nominal Output Voltage

+VDC

4.75

5.0

5.25

V

RT7640-5V

2

Line Regulation

VLINE

 

0.1

 

%

@ 50% Load

3

Load Regulation

VLOAD

 

1

 

%

@ VIN=48V

4

Output Ripple and Noise

VRN

 

180

 

mVp-p

@ Max load2

5

Minimum Load

RLOAD

200

 

 

mA

 

6

Short-Circuit Duration3

TSC

 

 

sec

 

7

Efficiency @ 80% Load

EFF

 

88

 

%

12V 1.5A load

 

Efficiency @ 80% Load

EFF

 

88

 

%

5V @ 3A load

8

Isolation Voltage (I/O)

VISO

 

1500

 

VPK

Impulse Test

9

Temperature Coefficient

TC

 

0.02

 

%

Per OC

 

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.

  • RT7640 Typical Connection Diagram 1000M Ethernet:
  • RT7640 Typical Connection Diagram 100M Ethernet:
    • Power Classification

    The RT7640 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

    The RT7640 has an 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 RT7640 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 RT7640 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 RT7640 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.

     

     

    • Package Size (mm   ±3mm )