View 2795T_1193347.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

HIGH FREQUENCY MAGNETICS
Application Note for Miniature Pulse Transformers
TM00145B
2795T and 2795Y Transformers Application Note
The 2795T and 2795Y transformers provide two transformation ratios to match both 75 and 120 line impedances with Lucent 3.3 V transceivers using a single terminating network design. These dual-ratio transformers can also be used for 100 lines with a change in resistor values. The 2795T is optimized for the receive function, while the 2795Y is optimized for the transmit function. The 2795T can be used for both receive and transmit operation; the 2795Y is designed for transmit operation only. Suggested applications for a single-transformer design solution (two 2795T transformers) are shown in Figure 1. The recommended two-transformer design solution (2795T and 2795Y) is shown in Figure 2. For 2795T and 2795Y data sheet refer to document TM00145.
Single-Transformer Design and Common Termination Network A typical line termination network using the 2795T transformer for both the receive interface and the transmit interface is shown below for a single channel. The termination network consists of capacitors and resistors arranged to provide the proper voltage gain and impedance matching to the characteristic impedance of the various transmission lines. The network is designed to operate with both E1 cable impedances (75 and 120) with no change in components. For DS1 applications (100), only the resistor values need to be changed. The same transformer can be used for all three cable impedances in both receive and transmit operation. Figure 1 below shows the proper connections for each cable impedance. Connections for cable selection are made on the line side for the receive interface and on the device side for the transmit interface. The components and suggested values are listed in Table 1. Capacitor CS provides high-frequency return loss enhancement.
(c)2000 Bel Fuse Inc.
Specifications subject to change without notice. 07.00
Bel Fuse Inc. 198 Van Vorst Street, Jersey City, NJ 07302 * Tel 201-432-0463 * Fax 201-432-9542 * www.belfuse.com T1-103
HIGH FREQUENCY MAGNETICS
TM00145B
Application Note for Miniature Pulse Transformers
2795T and 2795Y Transformers Application Note
2795T Transformer 4 3
Receive Data
RR RTIP CC
ZO (Line) 75 120 100 Transmit Data
2 5 1 T1 2795T Transformer 3 4 6
RS RR
RRING Device (1 Channel)
RT TTIP CS RT
2 ZO (Line) 6 T2
120 100 5 1 75
TRING
Figure 1. Connections for two 2795T transformers
Symbol Zo CC RR RS RT CS T1 T2
Name Characteristic impedance Center tap capacitor Receive series resistor Receive shunt resistor Transmit series resistor Shunt capacitor Bel part number--receive Bel part number--transmit
Value 75 (E1) 120 (E1) 0.1 F 0.1 F 158 158 114 114 6.2 6.2 470 pF 470 pF 2795T 2795T 2795T 2795T
100 (DS1) 0.1 F 132 95.3 1.2 470 pF 2795T 2795T
Table 1. Components and values for two 2795T transformers
(c)2000 Bel Fuse Inc.
Specifications subject to change without notice. 07.00
Bel Fuse Inc. 198 Van Vorst Street, Jersey City, NJ 07302 * Tel 201-432-0463 * Fax 201-432-9542 * www.belfuse.com T1-104
HIGH FREQUENCY MAGNETICS
Application Note for Miniature Pulse Transformers
TM00145B
2795T and 2795Y Transformers Application Note
Two-Transformer Design and Common Termination Network A typical line termination network using the 2795T transformer for the receive interface and the 2795Y transformer for the transmit interface is shown below for a single channel. The termination network consists of capacitors and resistors arranged to provide the proper voltage gain and impedance matching to the characteristic impedance of the various transmission lines. The network is designed to operate with both E1 cable impedances (75 and 120) with no change in components. For DS1 applications (100), only the resistor values need to be changed. The 2795T transformer is used for all three cable impedances at the receive interface. The 2795Y transformer is used for all three cable impedances at the transmit interface. Figure 2 below shows the proper connections for each cable impedance. Connections for cable selection are made on the line side for both receive and transmit interfaces. The components and suggested values are listed in Table 2. Capacitor CS provides high-frequency return loss enhancement.
Receive Data
2795T Transformer 4 3
RR RTIP CC
ZO (Line) 75 120 100 Transmit Data
2 5 1 T1 2795Y Transformer 4 2 6
RS RR
RRING Device (1 Channel)
3
RT TTIP
ZO (Line) 75 120 100
CS 5 1 T2 6 RT TRING
Figure 2. Connections for one 2795T transformer and one 2795Y transformer
(c)2000 Bel Fuse Inc.
Specifications subject to change without notice. 07.00
Bel Fuse Inc. 198 Van Vorst Street, Jersey City, NJ 07302 * Tel 201-432-0463 * Fax 201-432-9542 * www.belfuse.com T1-105
HIGH FREQUENCY MAGNETICS
TM00145B
Application Note for Miniature Pulse Transformers
2795T and 2795Y Transformers Application Note
Symbol Zo CC RR RS RT CS T1 T2
Name Characteristic impedance Center tap capacitor Receive series resistor Receive shunt resistor Transmit series resistor Shunt capacitor Bel part number--receive Bel part number--transmit
Value 75 (E1) 120 (E1) 0.1 F 0.1 F 158 158 114 114 7.15 7.15 330 pF 330 pF 2795T 2795T 2795Y 2795Y
100 (DS1) 0.1 F 132 95.3 1.8 330 pF 2795T 2795Y
Table 2. Components and values for one 2795T transformer and one 2795Y transformer
(c)2000 Bel Fuse Inc.
Specifications subject to change without notice. 07.00
CORPORATE
Bel Fuse Inc. 198 Van Vorst Street Jersey City, NJ 07302 Tel 201-432-0463 Fax 201-432-9542 www.belfuse.com
FAR EAST
Bel Fuse Ltd. 8F / 8 Luk Hop Street San Po Kong Kowloon, Hong Kong Tel 852-2328-5515 Fax 852-2352-3706 www.belfuse.com
EUROPE
Bel Fuse Europe Ltd. Preston Technology Management Centre Marsh Lane, Suite G7, Preston Lancashire, PR1 8UD, U.K. Tel 44-1772-556601 Fax 44-1772-888366 www.belfuse.com
T1-106

▲Up To Search▲

Price & Availability of 2795T

	To Download 2795T Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .