TXC-02050 Transwitch, TXC-02050 Datasheet - Page 16

• Manufacturer Part Number: TXC-02050
• Description: Line Interface
• Manufacturer: Transwitch

OVERVIEW
Line Side Input Impedance
The input impedance of the MRT is a function of the state of the LOW lead and the operating rate. Table 1 lists
the input impedance of the MRT at the operating line rates (which are 1/2 the bit rates).
Line Side Input Sensitivity
The input voltage sensitivity of the MRT depends on the state of the LOW lead as shown in Table 2 below.
Line Side Input Circuit
The circuit shown in Figure 11 illustrates the component required for operating the MRT device for 34368,
8448 or 6312 kbit/s. The transformer should have a frequency response of 0.2 to 80 MHz with an insertion loss
of 1 dB, maximum. TranSwitch recommends the use of a Coilcraft transformer (part no. WB-1010) or equiva-
lent). This gives return loss and isolation voltage values that meet or exceed requirements.
Line Side Output Characteristics
The line side output of the MRT switches from “rail to rail” on both of its output leads, TPO and TNO. This pro-
vides the maximum voltage swing, and makes the output voltage depend on the +5 volt power supply input to
the chip. The external circuit design must therefore be done with care in order to assure the meeting of the
amplitude requirements.
LOW = 1, line rate = 17184 kbit/s
LOW = 0, line rate = 4224 kbit/s
LOW = 0, line rate = 3156 kbit/s
LOW Lead
0
1
Receive
Input
Data
Condition
Figure 11. Line Side Input Circuit
Table 1. MRT Input Impedance
Table 2. MRT Input Sensitivity
10/6.3
1 : 1
+
Input Sensitivity (peak volts)
- 16 -
0.15
0.1
75
5%
Min
0.5
10/6.3
Minimum Input Impedance, | Z |
+
29
30
TXC-02050
0.1
1.1
2.7
1260 ohms
2390 ohms
3670 ohms
Max
Device
MRT
(6 & 8 Mbit/s)
(34 Mbit/s)
Ed. 3, April 1994
TXC-02050-MB
MRT