Multi-Tech Systems Modem Module MT3334SMI - Manual (Page 14)

ModemModule Developer’s Guide
MT3334SMI 14
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.
6
5
4
3
2
1
J1
Loaded 4 Pin Modjack
x
x
x
x
C2 220PF/2KV
FB2
FERRITE-600
FERRITE-600
220PF/2KV C1
FB1
TR600-150
R1
TIP
RING
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 3 rd edition protection against overvoltage from power
line crosses.