ISDN S-Interface Transformers
Surface Mount, Dual, 2000 Vrms
Meets pulse waveform template of CCITT I.430 when
recommended transformer and chip pair are used
Excellent longitudinal balance
2kVrms isolation voltage
Available in tape and reel, tray or tube packaging
Recognized by UL
Part
Number
A
PE-65793
PE-65795
Ratio
(±2%)
B
1:1
1:2
1:1
1:2
OCL Pri
(mH MIN)
A&B
22
22
Electrical Specifications @ 25°C - Operating Temperature 0°C to +70°C
L L Sec
Cw/w
CD Pri
DCR Pri
(μH MAX)
(pF MAX)
(pF MAX)
(Ω
±25%)
A
5
15
B
5
15
A&B
100
100
A
42
80
B
42
80
A
2.4
4.3
B
2.4
4.3
DCR Sec
(Ω
±25%)
A
2.4
4.3
B
2.4
4.3
∆
I
DC C
(mA MAX)
1
1
Package /
Schematic
SC-1
SC-1
Mechanical
SC-1
.120 TYP
3,05
.720 MAX
.530 MAX
18,29
13,46
.600
15,24
8
.050 TYP
1,27
SEC
Schematic
16 15 14 13
12 11 10 9
16
9
Date Code
Country of Origin
PE-6579X
.760 .520
19,30 13,21
PRI
16X .030
0,76
.950 MAX
24,13
.100 TYP
2,54
.700
17,78
1
SUGGESTED PAD LAYOUT
2 3 4
COIL A
5
6 7 8
COIL B
.390 MAX
9,91
.122
3,10
.100
2,54 .010/.020
0,25/0,51
.004/0,10
16 SURFACES
.040/.050
1,02/1,27
Dimensions:
Inches
mm
Unless otherwise specified,
all tolerances are
±
.010
0,25
USA 858 674 8100
1
Germany 49 7032 7806 0
Singapore 65 6287 8998
Shanghai 86 21 62787060
China 86 755 33966678
Taiwan 886 3 4356768
T604.F (05/12)
pulseelectronics.com
ISDN S-Interface Transformers
Through Hole, Single & Dual, 2000 Vrms
Meets pulse waveform template of CCITT I.430 when
recommended transformer and chip pair are used
Excellent longitudinal balance
2kVrms isolation voltage
Recognized by UL
Electrical Specifications @ 25°C - Operating Temperature 0°C to +70°C
2kV Isolation, Through Hole, Single Transformers
Part
Number
PE-64995NL
Ratio
(±2%)
1CT:2CT
OCL Pri
(mH MIN)
22
L L Sec
(μH MAX)
15
Cw/w
(pF MAX)
100
CD Pri
(pF MAX)
80
DCR Pri
(Ω
±25%)
2.5
DCR Sec
(Ω
±25%)
4.3
Isolation
(V
RMS
MIN)
2000
∆
I
DC C
(mA MAX)
1
Package /
Schematic
SC-1
Mechanical
IS-1
.558
MAX
14,20
1
2
3
6
PE-6499X
5
DATE CODE
Schematic
.400
10,20
.400
MAX
10,20
PRI : SEC
1
6
5
4
.558
MAX
14,20
.400
10,20
C
L
2
3
4
.120 – .020
3,10 0,30
C
L
LEADS ARE 22 AWG SOLDERABLE
Electrical Specifications @ 25°C - Operating Temperature -40°C to +125°C
Turns Ratio
Part
Number
PE-65495NL
Ratio
A
1:2
Equivalent
Single
1-4
Primary
Pins
1-4
Secondary
Pins
16-13
Ratio
A
1:2
DCR
(mΩ MAX)
Equivalent
Single
PE-64995NL
Primary
Pins
5-8
Secondary
Pins
12-9
Package /
Schematic
ID-1
Mechanical
ID-1
Schematic
COIL A
COIL B
16 15 14 13 12 1110 9
SEC
PRI
1
2 3
4
5
6 7
8
2
pulseelectronics.com
T604.F (05/12)
ISDN S-Interface Transformers
Transformer Selection & Packaging
IC
Manufacturer
AT&T/Lucent
Mietec
Mitel
Motorola
National
D
SGS Thomson
Siemens
Yamaha
Notes:
T7903
IC
Part Number
Dual
Surface Mount
TX & RX
PE-65795
PE-65795
PE-65795
PE-65795
PE-65795
PE-65795
PE-65795
PE-65795
TX
Single
Through Hole, 2 kV
RMS
RX
PE-64995NL
PE-64995NL
PE-64995NL
-
PE-64995NL
PE-64995NL
PE-64995NL
PE-64995NL
PE-64995NL
PE-64995NL
PE-64995NL
-
PE-64995NL
PE-64995NL
PE-64995NL
PE-64995NL
Dual
Through Hole
TX & RX
PE-65495
PE-65495
PE-65495
PE-65495
PE-65495
PE-65495
PE-65495
PE-65495
MTC-2072
MT8930
MC145474/145475
MC145574
TP3420/34221
ST5420, ST5421
PEB 2080/2081/2085
PSB 2186
PEB 2084/2086
7405B
A. In this catalog, turns ratio is expressed as
“primary:secondary”. The term “CT” designates a
center tapped winding. A center tapped winding
can be created by connecting 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 transmistter
output and receiver input impedance requirements of
CCITTI I.430 for both the TE and the NT. The maximum
distributed capacitance 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 connectin only half the secondary
winding. See National’s application note.
E. PE-65950 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 -40C is 27 H minimum. For
maximum performance, using 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
Package
F
LA-1
SC-1
ID-1
IS-1
Type
SMT
SMT
THT
THT
Part Weight
2.0 Grams
7.0 Grams
7.0 Grams
4.0 Grams
Parts/Tube
30
20
20
35
Parts/Tray
60
50
-
-
Parts/Reel
250
150
-
-
Reel Diameter
13 Inches
13 Inches
-
-
Tape Width
24 mm
44 mm
-
-
Pitch
24 mm
24 mm
-
-
3
pulseelectronics.com
T604.F (05/12)
ISDN S-Interface Transformers
Surface Mount, Dual, 2000Vrms
TE
Sec : Pri
S-INTERFACE
IC
XMIT
Sec : Pri
RCV
Low
Freq
Choke
High
Freq
Choke
High
Freq
Choke
Low
Freq
Choke
Pri : Sec
Pri : Sec
NT
IC
RCV
XMIT
Local
Power
DC
Supply
Figure 1. Typical ISDN S-Interface Application Circuit
1. General Information
- The S-interface is the
standardized four-wire digital telephone access point
defined by the CCITTI I-series recommendations for
the Integrated Services Digital Network. This “basic
rate access” accommodates two 64Kpbs “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
manufacturers 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
longitudinal 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 compliances of the system with
I.430 on longitudinal conversion loss (LCL) and signal
balance. This is accomplished 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.
(continued on next page)
4
pulseelectronics.com
T604.F (05/12)
ISDN S-Interface Transformers
Surface Mount, Dual, 2000Vrms
HP-8751A
Network Analyzer
Out
R
A
B
ISM-1 = Wandel and Goltermann
Signal Balance Ratio Bridge
Pri
VT
EL
ISM-1
Sec
Terminating
Resistor
Figure 2. Longitudinal Balance Test Circuit
2.
(continued from previous page)
A recommended
test set up is shown in Figure 2. A high inductance “low
frequency” is common mode choke, such as PE-
65950NL or PE-65853NL, is recommended to improve
balance, or to correct inherent unbalances of some
circuits.
3. 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 somewat 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 buget is 800pF. As a rule, the
capacitances should be kept as low as possible in the
interface circuit design. With the specified transformer
capacitances, it is possible to remain within budget
and have a reasonable margin for measurement errors.
4. 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.
5. Surge Voltage Capability for Transformers and
Chokes
• Longitudinal Voltage Peak: 2,400V 10/700μsec
• Metallic Voltage Peak: 800V 10/560μsec
6. 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 minues without
permanent damage. Such current may be cauased 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
1500W resistive or 400 to 600W inductive limiting.
These may cause peak currents.
7. Flammability - Materials used in the products are
recognized UL94-VO. Products meet the requirements
of IEC 695-2-2 (Needle Flame Test).
5
pulseelectronics.com
T604.F (05/12)
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