LXT312A/LXT315A — Low Power T1 PCM Repeaters/Transceivers
3.0
3.1
Application Information
Introduction
shows a typical T1 dual repeater/transceiver application using an LXT312A repeater/
transceiver with standard PCB edge connectors. It includes a jumper-selectable shorting option
(dashed lines at connector pins 2 and 7) for the fault location circuitry.
lists the
specifications for the crystal used with the LXT312A or LXT315A repeater.
3.1.1
Alternate Timing Reference
For applications where a crystal is not appropriate, a 1.544 MHz or 6.176 MHz, CMOS-level (High
≥
4.5V, Low
≤
0.5V) oscillator may be connected to XTI. In this situation, XTO must be tied to
VCC and GND via a voltage divider as shown in
Table 2.
Crystal Specifications
Parameter
Frequency
Frequency tolerance
1
Effective series resistance
Crystal cut
Resonance
Maximum drive level
Mode of operation
Specification
6.176 MHz
± 50 ppm
40
Ω
Maximum
AT
Parallel
2.0 mW
Fundamental
1. @ 25 °C, C Load = 10 pF; and from -40 °C to +85 °C
(Ref 25 °C reading).
10
Datasheet
ETC [ ETC ]
