AK61584 Datasheet, PDF (14/38 Pages) Asahi Kasei Microsystems – Dual Low Power T1/E1 Line Interface

ASAHI KASEI
[AK61584¹]⁴
V = 100%
269 ns
(244 + 25)
194 ns
(244 – 50)
Nominal pulse
50%
244 ns
219 ns
(244 – 25)
0%
488 ns
(244 + 244)
Note – V corresponds to the nominal peak value.
Figure 9. Typical Pulse Shape at DSX-1 Cross Connect Figure 10. Mask of the Pulse at 2048kbps Interface
The line driver internally matches the impedance of the
line load, providing 14 dB of return loss during the
transmission of both marks and spaces. This improves
signal quality by minimizing reflections off the trans-
mitter. Internal impedance matching reduces current
consumption by factor of nearly two compared to return
loss achieved by external resistors.
The transmitter provides for all ones insertion at the
frequency of REFCLK. Transmit all ones is selected
when TAOS goes high, and causes continuous ones to
be transmitted on the line (TTIP and TRING). In this
mode, the TPOS and TNEG, or TDATA, inputs are ig-
nored.
When any transmit control pin (TAOS, LLOOP, or
CON<0-2>) is toggled, the transmitter stabilizes within
22 bit periods. The transmitter will take longer to stabi-
lize when RLOOP is selected because the timing cir-
cuitry must adjust to the new frequency.
Recommended transmitter transformer specifications
are shown below:
When the transmitter transformer secondaries are
shorted via a 0.5ohm resistor, the transmitter will out-
put a maximum of 50 mA-rms, as required by the Bri-
tish OFTEL OTR-0001 specification.
Turns ratio
Primary inductance
Primary leakage
Inductance
Secondary leakage
Inductance
Interwinding
Capacitance
ET-constant
1:2 step-up for TX(T1)
1:2 step-down for RX(T1)
1:1.32 step-up for TX(E1)
1:1.32 step-down for RX(E1)
1.5 mH min measured at
772 kHz
0.3 uH max at 772 kHz
with secondary shorted
0.4 uH max at 772 kHz
18 pF max, primary to
secondary
16 V-us min
Table 2(a). Transformer Requirements
Turns Ratio
1:2(T1)
1:1.32(E1)
Part#
PE-65351
4023
67148170
4022
Manufacturer
Pulse Engineering
JPC Corporation
Schott Corporation
JPC Corporation
Table 2(b) Recommended Transformer
0185-E-00
-14-
‘98/04