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T1/CEPT/ISDN-PRI TRANSFORMERS
Application Notes
NOTES FROM TABLES (pages 1 through 6):
A. Toleranced leakage inductance: .30 µH min to .55 µH MAX.
B. OCL (primary inductance) and LL(leakage inductance) are
measured at the primary winding. Turns ratio is specified
primary: secondary. (CT = Center Tap; CS = Split Center
Tap).
C. To make a 1CT:1 ratio from a 1CT:2CT ratio, use only one
half of the secondary (2CT) winding.
D. For Reinforced 3kVrms Dual SMT Transformers, refer to
data sheet T617. For Quad SMT Transformers refer to data
sheet T615. For Octal SMT Transformers refer to data
sheet T622.
E. Dual Ratio Transformers — These transformers have
tapped secondary windings to provide two turns ratios
(T/R). Use the entire primary winding and connect the sec-
ondary pins listed below to obtain the desired turns ratio:
Part Turns Secondary Turns Secondary
Number Ratio 1 Pins Ratio 2 Pins
PE-65837 1:1.08 3-5 1:1.36 1 - 5
PE-65839 1:1 3-5 1:1.26 1 - 5
PE-65866 1:1 2-3 1:1.26 1 - 3
PE-68646 1:1.58 3-5 1:2 1 - 5
PE-65389 1:1 3-5 1:1.26 1 - 5
PE-65566 1:1 2-3 1:1.26 1 - 3
PE-65568 1:1 2-3 1:1.26 1 - 3
PE-68866 1:1 2-3 1:1.26 1 - 3
PE-68826 1:1 2-3 1:1.26 1 - 3
PE-68664 1:1 3-5 1:1.26 1 - 5
PE-68836 1:1 2-3/5-6 1:1.26 1-3/4-6
F. Standard packaging for surface mount “AN” and “LA” pack-
ages is anti-static tubes. Optional tray packaging can be
ordered by adding “R” suffix to the part number, (i.e. PE-
65857R). Optional Tape & Reel packaging can be ordered
by adding “T” suffix to the part number, (i.e. PE-65857T).
G. PE-64931 and PE-65351 are electrically equivalent, but
have different schematics. PE-65351 is both UL 1459 and
BABT recognized and is recommended for new designs
because the 3S schematic provides greater physical sepa-
ration between the primary and secondary pins.
H. PE-68618 and PE-64950: The fault locate winding is (7-8).
I. Safety Agency approvals pending.
J. The turns ratio of these devices have been designed, in
conjunction with semiconductor vendor recommendations,
to allow connections to various terminations (e.g. 75 or 120
Ωwith the same transformer). For example T1075 can be
used with the Siemens PEB 2235 to achieve connection to
the 75 or 120 Ωcable. For 75 Ωtermination, the PEB 2235
requires the following turns ratio: 1:1.57 (Tx) and 1:1.26
(Rx) which can be achieved using pins (1-2):(15-16) for Tx
and (10-11):(5-8) for Rx. For 120 Ω, the following turns
ratio are required: 1:2 (Tx) and 1:1 (Rx), which are pins (1-
2):(16-14) for Tx and (9-11):(5-8) for Rx on the T1075.
1. Extended Temperature Range Models — For extended temperature range
transformers (-40°C to +85°C operating temperature range), OCL (Open
Circuit Inductance for the primary winding) is specified at both -40°C and
+25°C. At -40°C, OCL is 600 µH minimum for all low temperature models with
the exception of PE-68827 which is 800 µH minimum and PE-65836 which is
300 µH minimum. All other parameters are specified at +25°C only. Standard
temperature range is 0°C to +70°C.
2. ET Product — All coils have an ET product of 10 V-µsec minimum.
3. Flammability — Materials used in the products are recognized
as UL94-VO approved. Products meet the requirements of IEC 695-2-2
(Needle Flame Test).
4. Balance Characteristics — The transformers meet the requirements for lon-
gitudinal balance of FCC part 68.
5. Common Mode Rejection Ratio — the CMRR for all transformers is better
than 50 dB at 1 MHz. A typical test circuit is shown below.
6. Crosstalk Attenuation — In the dual packages, which contain transmit and
receive transformers side by side, sufficient crosstalk attenuation is achieved
by the inherent characteristics of the toroid cores as well as by their proper
positioning. The crosstalk attenuation is typically 50 dB or better from 100
KHz to 10 MHz. This result was established with the test circuit shown below.
7. Return Loss — ITU-T G.703 and European national regulatory documents
specify minimum return loss levels. The transformers will allow these limits to
be complied within the situations where they are applicable.
Frequency 50-100 KHz 100 KHz-2 MHz 2-3 MHz
Return Loss
XMIT 9 dB 15 dB 11 dB
REC 12 dB 18 dB 14 dB
8. Surge Voltage Capability – All transformers and chokes
meet surge voltage tests according to the most stringent
regulatory documents when system designs include the proper voltage and
current suppression devices:
Metallic Voltage: 800 V peak, 10/560 µsec
Longitudinal Voltage: 2,400 V peak, 10/700 µsec
9. Isolation Voltage — 100% of transformers are tested during
production to the specified isolation voltage level.
10. Safety Agency Recognition — Parts listed as "Recognized" or "Certified"
meet Underwriter Laboratories, UL 1459 and UL 1950 per file E133523 (S).
British Approvals Board for Telecommunications
BABT BS 6301:1989/BS 415 and BS EN 41003:1991/EN 60 950, supple-
mentary insulation.
CR/0091
PE-64933 PE-65351 PE-65558 PE-68600
PE-64934 PE-65363 PE-65586 PE-68644
PE-64936 PE-65379 PE-65755 PE-68645
PE-64937 PE-65388 PE-65770 PE-68664
PE-64943 PE-65389 PE-65771
PE-65340 PE-65415 PE-65778
Transformers with Reinforced Insulation according to IEC950 series
PE-68630—PE-68788 (page 3) are certified by the
following organizations:
Code Certificate Information
C CSA, C22.2 #950 & #225, Cert. LR 76802-3, reinforced insulation.
T TÜV, EN 60 950/EN 41003, Cert. R9371358, reinforced insulation.
U UL 1459/UL1950, File E133523 (S), reinforced insulation.
B BABT EN41003/EN60950, Cert. CR0079, reinforced insulation.
(Note: Safety Agency approval of surface mount transformers is pending.)
11. General Information — The transformers are specifically designed for use
in 1.544 Mbps (T1), 2.048 Mbps (CEPT) and ISDN Primary rate (PRI) inter-
face applications. They are matched to the majority of the line interface
transceiver ICs currently available. Use of the proper transformer allows the
interface circuit to comply with ITU-T G.703 and other standards regarding
pulse waveform, return loss, and balance.
12. Common Mode Chokes — The “high-frequency” 4-lines common mode
chokes shown in this data sheet provide an effective means of compliance with
national and international regulations on EMI. They are designed to be used in
conjunction with Pulse’s T1/CEPT transformers as shown in the typical appli-
cation below. Crosstalk is typically -70 dB at 1 MHz and -55 dB at 10 MHz.