TQ8105S 查看數據表（PDF） - TriQuint Semiconductor

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TQ8105S

SONET/SDH Transceivers

TriQuint Semiconductor 

TQ8105/TQ8106

PRELIMINARY DATA SHEET

TQ8105/TQ8106 Design Notes

These design notes are provided to assist the circuit

designer in achieving the highest possible performance

while reducing design time. Unless noted otherwise,

references to the TQ8105 apply equally to the TQ8106.

Interfacing to PMC-Sierra Devices

The transmit timing of the TQ8105 is such that the

PMC-Sierra byte outputs (POUT(0:7)) may be directly

connected to the TQ8105 mux inputs (MXD(0:7)). The

TQ8105 uses an Out-Of-Frame (OOF) input as a signal

to reframe while high, allowing direct connection of the

PM5355's OOF output to the TQ8105 OOF input. The

following summarizes connectivity between the devices.

PM5355 TQ8105/TQ8106

POUT(0:7) MXD(0:7)

PIN(0:7) DXD(0:7)

OOF

OOF

PICLK

RXBC

FPIN

DXSYNC

TCLK

TXBC

POP(0:5) Any TQ8105 modes to be programmable

PIP(0:3) Any TQ8105 diag outputs to be readable

Reference Design

A reference design (see Figure 4) and evaluation board

are available from TriQuint. They incorporate a 1x9 or

2x9 fiber optic transceiver (with the option of clock

recovery), the PM5355 PMC Sierra framer device, and

a TQ8105 or TQ8106.

Thermal Considerations

Figure 9 shows the region where the use of a heatsink is

not required. For example, the TQ8105 does not require

a heatsink for ambient temperatures up to 55°C in still

air. An airflow of 100 LFPM raised this temperature to

approximately 75°C, eliminating heatsink requirements.

clips soldered to the board to cross and hold the

heatsink. The clip holes in the board are at the corners of

a 1.275” x 1.5” rectangle. Another alternative is the

circular heatsink, #2288B from Thermalloy attached with

their Thermattach #19686-3.

Power Supplies

Good decoupling practices should be observed, with a

0.1 uF decoupling capacitor at each supply pin, ideally

on the component side of the board. Keep the analog

supplies (Vdd and AVdd) pristine. Proper design will

isolate the supply groups using point grounding to tie

supplies together (all grounds at a single point having

multiple vias).

For the analog supply, flood copper under the loop filter

on the component side of the board, tying the flood to

the analog ground pin, with the point ground away from

the filter and analog pin, so that any switching currents

are kept away from these areas. If any switching,

power-supply frequencies below 500 kHz are used in

the system, use a supply filter on the analog supply pin.

These practices help minimize the generation of jitter.

High-Speed Connections

Connections to E/O modules (and clock reference, if

used) are direct-coupled PECL and need to be terminated

with decoupled 50 ohms to 3V at the receiving end of the 50

ohm transmission line. Ensure that each 50 ohm resistor

(or Thevenin equivalent) has its own decoupling

capacitor. Place the resistor at the end of a 50 ohm

transmission line (use a controlled impedance layer),

ideally with a minimal-length stub attached to either the

resistor or the receiving device.

If there is no room for the resistor, use a minimal-

length stub to drop the signal at the receiving device

pins, continue the 50 ohm transmission line to an area

where the termination resistors can be placed, and

terminate at the endpoint of that line. If in doubt,

contact factory applications for assistance.

In applications requiring a heatsink, a standard pin-fin

heat-sink is appropriate. To attach the sink, use spring

For additional information and latest specifications, see our website: www.triquint.com

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