ModemModule Developer’s Guide

MT3334SMI Design Considerations

This section discusses hardware considerations, PC board layout considerations, and Telecom labeling requirements.

Hardware Considerations

Disclaimer: Multi-Tech Systems makes no warranty claims for vendor product recommendations listed below. Other vendor products may or may not operate satifactorily. Multi-Tech System’s recommended vendor products only indicate that the product has been tested in controlled conditions and were found to perform satisfactorily.

C2220PF/2KV

TIP

RINGR1

TR600-150

FB2

FERRITE-600

FB1

FERRITE-600

J1

x6

x5

4

3

x2

x 1

Loaded 4 Pin Modjack

C1220PF/2KV

Figure 1-7. Tip and Ring Ferrite Connections

EMC: Surface mount ferrites are used on T&R (Tip and Ring) to mitigate emission levels out the RJ- 11 cable. 220pF capacitors are also used on T&R to reduce the common mode emissions that may be present in certain systems. The ferrite and capacitors also aid in reducing the effects of transients that may be present on the line.

Recommended Ferrite

Manufacturer – Associated Component Technology (ACT)

Part # - YCB-1206

Manufacturer – Murata Erie

Part # - BLM31A601SPT

Recommended Capacitor

 

Manufacturer – Murata Erie

Manufacturer - Ever Grace Electronic Industrials

Part # - GHM3045X7R221K-GC(Surface mnt)

Part # - YP221K2EA7PS

Part # - DE0807B221K-KH (Thru-hole device)

 

Note: The capacitors used on T&R must have a Y2 safety rating.

Telecom: The RJ-11 connector must meet FCC Part 68 requirements. Refer to FCC Part 68 section 68.500 subpart F for connector specifications. A self-healing fuse is used in series with line to help prevent damage to the DAA circuit. This fuse is needed for FCC Part 68 compliance.

Recommended Connector

Manufacturer – Stewart

Part # - 6446S/RP-30

Recommended Fuse

Manufacturer – RayChem

Part # - TR600-150

Note: The fuse is also needed to meet UL1950 3rd edition protection against overvoltage from power line crosses.

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MT3334SMI

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Multi-Tech Systems manual MT3334SMI Design Considerations, Hardware Considerations