Preliminary Information

MT8843

5-29

The crystal specification is as follows:

Frequency:

3.579545 MHz

Frequency tolerance:

±0.1%(-40°C+85°C)

Load capacitance:

18 pF

Maximum drive level (mW):

2 mW

e.g., CTS MP036S

Any number of MT8843 devices can be connected

as shown in Figure 8 such that only one crystal is

required. The connection between OSC2 and OSC1

can be D.C. coupled as shown, or the OSC1 inputs

on all devices can be driven from a CMOS buffer (dc

coupled) with the OSC2 outputs left unconnected.

VRef and CAP Inputs

Applications

The circuit shown in Figure 9 illustrates the use of the

MT8843 (CNIC2) device in a typical CID or CLIP sys-

tem. Network protection will differ depending on the

market for which the product is designed.

Notes:

CNIC2 has not been fully characterized for talkoff

and talkdown performance as specified in SR-TSV-

002476.

For CIDCW, speech immunity improves if near end

audio is cancelled from the incoming signal.

One

possible implementation is to connect the signal

input to the 2 wire side when the CPE is on-hook and

the 4 wire side when the CPE is off-hook.

Figure 9 - Application Circuit

IN+

IN-

GS

TRIGin

TRIGRC

TRIGout

MODE

OSCin

OSCout

St/GT

ESt

StD

INT

DR

DATA

DCLK

FSKen

PWDN

IC

CNIC2

CAP

CD

(FSK Interface Mode 0 selected)

+5V

= To microcontroller

= From microcontroller

TIP / A

RING / B

Notes

MT8843

+5V

+5V

+5V

430K

430K

34K

34K

464K

500K

500K

200K

300K

0.1µF

0.1µF

0.01µF

0.01µF

420K

420K

TISP4180,

TPA150A12 or

TPB150B12

TISP5180,

+5V

100K

For BT network

protection:

Note: For CTA applications where there is a requirement to determine

the ring burst duration, the value of R and C may have to be optimized.

C

R