PE-65798 Datasheet PE-65798T, PE-65498NL, PE-65799T | P4-P6

ISDN S-INTERFACE

TRANSFORMERS

Transformer Selection and Packaging

IC IC Dual Single Dual Single

Manufacturer Part Number Surface Mount Through Hole, 2 KVrms Through Hole Through Hole, 3 KVrms

NOTES

A. In this catalog, turns ratio is expressed as

“primary:secondary”. The term “CT” designates a center

tapped winding. The term “CS” designates a split center tap

winding. A center tapped winding can be created by connect-

ing two ends of a split center winding together on the printed

circuit board. In ISDN-S applications, the primary winding is

the line side transformer winding.

B. The minimum primary inductance and the maximum

distributed capacitance satisfy the transmitter output and

receiver input impedance requirements of CCITT I.430 for

both the TE and the NT. The maximum distributed capaci-

tance allows sufficient margin for the capacitance of the IC

and a protection diode network. It is consistent with the

overall maximum value specified and the permitted length of

the basic access TE cord.

C. The maximum specified unbalanced DC current capability is

based on 20 mH minimum primary OCL.

D. National recommends a 1:2 receive transformer, but used as

a 1:1 ratio by connecting only half the secondary winding.

See National’s application note.

E. PE-65950, PE-68613 and PE-65853 are recommended for

use with Siemens PEB 2080/2085 and help in meeting the

required longitudinal balance.

F. Standard packaging for all chokes and transformers listed in

this catalog is anti-static tubes. Optional anti-static tray

packaging can be ordered for the surface mount SC-1 and

LA-1 packages by adding an “R” suffix to the part number,

(ie: PE-65795R). Optional tape and reel packaging can be

ordered for all surface mount packages by adding a “T” suffix

to the part number, (ie: PE-65795T).

G. For PE-65854, OCL at -40°C is 27 µH minimum. For maxi-

mum performance use windings (1-8) and (2-7) as a pair and

windings (3-6) and (4-5) as a pair.

H. For transformers and choke modules, refer to data sheet T632.

Packaging Information

Trans & Rec Transmit Receive Trans & Rec Transmit Receive

AMD

Am 79C30A/79C32A

PE-65799 PE-64999 PE-64999 PE-65499 PE-68999 PE-68999

AT&T/Lucent

T7250/7256/7259

PE-65798 PE-64998 PE-64998 PE-65498 PE-68998 PE-68998

T7903

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

Mietec

MTC-2072

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

Mitel

MT8930

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

Motorola

MC145474/145475

PE-65793 PE-64993 PE-64993 PE-65493 PE-68993 PE-68993

MC145574

PE-65798 PE-64998 PE-64998 PE-65498 PE-68998 PE-68998

National

TP3420/3421

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68992

SGS Thomson

ST5420, ST5421

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

PEB 2080/2081/2085

Siemens PSB 2186 PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

PEB 2084/2086

Yamaha

7405B

PE-65795 PE-64995 PE-64995 PE-65495 PE-68995 PE-68995

Package

Type Part Weight Parts/Tube Parts/Tray Parts/Reel Reel Diameter Tape Width Pitch

LA-1 SMT 2.0 grams 30 60 250 13 inches 24 mm 24 mm

PA-2 SMT 4.0 grams 35 – 150 13 inches 32 mm 24 mm

SC-1 SMT 7.0 grams 20 50 150 13 inches 44 mm 24 mm

SH-4 SMT 0.3 grams 25 – 1500 13 inches 24 mm 12 mm

ID-1 THT 7.0 grams 20 – – – – –

IN-1 THT 2.5 grams 35 – – – – –

IS THT 4.0 grams 35 – – – – –

VC-1 THT 3.5 grams 40 – – – – –

WD-1 THT 9.0 grams 25 – – – – –

(See Pages 4 and 5 for Table Notes)

USA 858 674 8100

••

UK 44 1483 401 700

••

France 33 3 84 35 04 04

••

Singapore 65 6287 8998

••

Shanghai

86 21 32181071

••

China 86 769 5538070

••

Taiwan 886 2 26980228

www.pulseeng.com

4 T604.D (1/06)

ISDN S-INTERFACE

TRANSFORMERS

Application Notes

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.

2. Longitudinal Balance for Transformers – The longitudi-

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

20dB/decade.

XMIT

Sec : Pri

RCV

High

Freq

Choke

RCV

XMIT

Low

Freq

Choke

Low

Freq

Choke

High

Freq

Choke

S-INTERFACE

Local

Power

Supply

Pri : Sec

NTTE

Sec : Pri Pri : Sec

Figure 1. Typical ISDN S-Interface Application Circuit

(continued on next page)

USA 858 674 8100

••

UK 44 1483 401 700

••

France 33 3 84 35 04 04

••

Singapore 65 6287 8998

••

Shanghai

86 21 32181071

••

China 86 769 5538070

••

Taiwan 886 2 26980228

www.pulseeng.com

5 T604.D (1/06)

ISDN S-INTERFACE

TRANSFORMERS

Application Notes

A recommended test setup is shown in Figure 2. A high

inductance “low frequency” common mode choke, such as

PE-65950 or PE-65853, is recommended to improve

balance, or to correct inherent unbalances of some circuits.

4. Impedance Requirements – The requirements for

minimum impedance in the inactive and powered-down

states are expressed by impedance templates for both

transmitter and receiver in NT and TE. At the low

frequency end of 1MHz, it is reasonable to assume that

the impedance seen from the line is entirely capacitive.

The maximum capacitance budget, derived from the

templates, is somewhat different for the NT and the TE.

Contributors to the total capacitance are: the chip output,

the protection circuit, the transformer, common mode

choke and any other element that may be present. In the

TE case, there is also the maximum allowable TE cord

impedance. Here the maximum budget is 800pF. As a

rule, the capacitances should be kept as low as possible

in the interface circuit design. With the specified trans-

former capacitances, it is possible to remain within budget

and have a reasonable margin for measurement errors.

5. Common Mode Chokes – The “high frequency” 4-wire

common mode chokes shown on pages 7 and 8 provide

an effective means of compliance with national and

international regulations on EMI. They are designed to be

used in conjunction with either Pulse’s ISDN S-Interface or

T1/CEPT transformers as shown in Figure 1. A high

inductance “low frequency” common mode choke is

recommended to improve balance, or to correct inherent

unbalances of some ISDN S-Interface circuits.

6. Surge Voltage Capability for Transformers and Chokes

• Longitudinal Voltage Peak: 2,400V 10/700µsec

• Metallic Voltage Peak: 800V 10/560µsec

7. Behavior Under Fault Conditions – Telephony voltages

may accidentally appear on the ISDN S-Interface line to

the transformer. The transformer will withstand a DC

current of 0.5 Amps for 15 minutes without permanent

damage. Such current may be caused by the telephone

central battery. The transformer will also survive ringing

voltages. These are nominally 120V or 200V maximum at

20 to 60Hz, limited by 1500Ω resistive or 400 to 600Ω

inductive limiting. These may cause peak currents.

8. Flammability – Materials used in the products are recog-

nized UL94-VO. Products meet the requirements of IEC

695-2-2 (Needle Flame Test).

Out

HP-8751A

Network Analyzer

RBA

ISM-1

Pri Sec

Terminating

Resistor

ISM-1 = Wandel and Goltermann

Signal Balance Ratio Bridge

Figure 2. Longitudinal Balance Test Circuit

(continued from previous page)

USA 858 674 8100

••

UK 44 1483 401 700

••

France 33 3 84 35 04 04

••

Singapore 65 6287 8998

••

Shanghai

86 21 32181071

••

China 86 769 5538070

••

Taiwan 886 2 26980228

www.pulseeng.com

6 T604.D (1/06)

P1-P3 P4-P6 P7-P8

PE-65798

Mfr. #:

Buy PE-65798

Manufacturer:

Pulse Electronics

Description:

Audio Transformers / Signal Transformers SMD ISDN S-Interface 22mH 5.8Ohms

Lifecycle:

New from this manufacturer.

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PE-65798

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