PE-65950NL PULSE ELECTRONICS CORPORATION, PE-65950NL Datasheet - Page 5

• Manufacturer Part Number: PE-65950NL
• Description: Audio & Signal Transformers TRANSFORMER DUAL
• Manufacturer: PULSE ELECTRONICS CORPORATION

Specifications of PE-65950NL

• Package Type: DIP
• Mounting: Through Hole
• Pin Count: 8
• Lead Style: PC Pin
• Ocl Inductance (max): 4.7(Typ)mH
• Product Depth (mm): 14.17mm
• Product Height (mm): 10.16mm
• Product Length (mm): 14.17mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ISDN S-INTERFACE
TRANSFORMERS
Application Notes
www.pulseeng.com
1. General Information – The S-interface is the standard-
ized four-wire digital telephone access point defined by
the CCITT I-series recommendations for the Integrated
Services Digital Network. This “basic rate access” accom-
modates two 64Kbps “B-channels” for information, one
16Kbps “D-channel” intended for signaling and control,
and 48 Kbps for framing and other purposes, giving a total
rate of 192Kbps. The CCITT physical layer recommends
that the user network interface be transformer coupled.
A typical application circuit is presented in Figure 1.
The transformer provides isolation for the line card or the
terminal from the line. It is also a way to provide phantom
power feeding to the terminal over the S-loop. Each end
requires a transmit and a receive transformer. Chokes are
used in some applications to reduce common mode noise
(see note 5).
The transformers described in this data sheet are
matched to the transceivers offered by the major IC manu-
facturers listed. The use of a transformer-chip pair
assures that all requirements of CCITT I.430 are met with
respect to pulse waveform templates, impedance and
longitudinal balance. In addition, the transformers provide
the isolation voltages required by the regulatory agencies
and are capable of passing surge voltage tests.
XMIT
USA 858 674 8100
RCV
IC
TE
• •
Sec : Pri
Sec : Pri
UK 44 1483 401 700
Power
Local
• •
Figure 1. Typical ISDN S-Interface Application Circuit
France 33 3 84 35 04 04
Choke
Freq
Low
Choke
High
Freq
• •
Singapore 65 6287 8998
S-INTERFACE
5
2. Longitudinal Balance for Transformers – The longitudi-
• •
Shanghai
nal conversion loss specification in I.430 includes a test
setup that is intended for system evaluation, whether TE
or NT. Such a test is performed with DC current present.
The transformer plays an essential role in achieving the
required balance. However, all other elements in the
circuit should be also designed to provide the highest
possible symmetry. These elements include the protection
circuitry, series resistors, chip transmitter output and
receiver input, as well as the cables used and the TE cord
where applicable. A high level of transformer balance
compensates for some circuit AC-unbalance, and assures
compliance of the system with I.430 on longitudinal
conversion loss (LCL) and signal balance. This is accom-
plished by a well AC-balanced winding configuration
whereby the capacitive coupling between primary and
secondary windings is evenly distributed. Also, both
halves of the lineside winding are well balanced. The
transformers meet the following LCL specifications:
• 10kHz to 300kHz: 60dB minimum
• 300kHz to 1MHz: Minimum value decreasing
Choke
High
Freq
86 21 32181071
20dB/decade.
Choke
Freq
Low
• •
China 86 769 5538070
Pri : Sec
Pri : Sec
Supply
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DC
• •
Taiwan 886 2 26980228
NT
T604.D (1/06)
XMIT
RCV
IC