T1/CEPT/ISDN-PRI TRANSFORMERS
Application Notes
NOTES FROM TABLES (pages 1 through 6):
A. Toleranced leakage inductance: .30µH min to .55µH MAX.
B. OCL (primary inductance) and L
L
(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 Tape & Reel packaging
can be ordered by adding “T” suffix to the part number,
(i.e. PE-65857T).
G. PE-68618 and PE-64950: The fault locate winding is (7-8).
H. Safety Agency approvals pending.
I. 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
120Ω with the same transformer). For example T1075 can
be used with the Siemens PEB 2235 to achieve connection
to the 75 or 120Ω cable. For 75 Ω termination, 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 120Ω, 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 typically50 dB or better from 100kHz
to 10MHz. 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 50-100kHz 100kHz-2 MHz 2-3MHz
Return Loss
XMIT 9 dB 15dB 11dB
REC 12 dB 18dB 14dB
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: 800V peak, 10/560µsec
Longitudinal Voltage: 2,400V peak, 10/700µsec
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).
Transformers with Reinforced Insulation according to IEC950 series
PE-68630—PE-68788 (pg. 3) are certified by the following organizations:
Code Certificate Information
T TÜV, EN 60 950/EN 41003, Cert. R9371358, reinforced insulation.
U UL 1459/UL1950, File E133523 (S), reinforced insulation.
11. General Information — The transformers are specifically designed for use
in 1.544 Mbps (T1), 2.048 Mbps (CEPT) and ISDN Primary rate (PRI)
interface 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
application below. Crosstalk is typically -70dB at 1MHz and -55dB at 10MHz.
