TORX198

2001-08-10

6

7. Precaution on Use

(1)

Maximum rating

The maximum ratings are the limit values which must not be exceeded during operation of device.

None of these rating value must not be exceeded. If the maximum rating value is exceeded, the

characteristics of devices may never be restored properly. In extreme cases, the device may be

permanently damages.

(2)

Soldering

Optical modules are comprised of internal semiconductor devices. However, in principle, optical

modules are optical components. During soldering, ensure that flux does not contact with the emitting

surface or the detecting surface. Also ensure that proper flux removal is conducted after soldering.

Some optical modules come with a protective cap. The protective cap is used to avoid malfunction

when the optical module is not in use. Note that it is not dust or waterproof.

As mentioned before, optical modules are optical components. Thus, in principle, soldering where

there may be flux residue and flux removal after soldering is not recommended. Toshiba recommend

that soldering be performed without the optical module mounted on the board. Then, after the board

has been cleaned, the optical module should be soldered on to the board manually.

If the optical module cannot be soldered manually, use non−halogen (chlorine−free) flux and make

sure, without cleaning, there is no residue such as chlorine. This is one of the ways to eliminate the

effects of flux. In such a cases, be sure to check the devices’ reliability.

(3)

Noise resistance

It is believed that the use of optical transfer devices improve noise resistance. In theory, optical fiber

is not affected by noise at all. However, receiving modules which handle signals whose level is

extremely small, are susceptible to noise.

TOSLINK improve noise resistance to use a conductive case. However, the current signal output by

the optical receiving modules’ photodiode is extremely small. Thus, in some environments, shielding

the case may not achieve sufficient noise resistance.

First systems which incorporate TOSLINK, Toshiba recommend testing using the actual device to

check its noise resistance.

Use a simple noise filter on TOSLINK fiber optic transceiving module’s power line. If the ripple in the

power supply used is significant, reinforce the filter.

The optical module is to be used in an area which is susceptible to radiated noise, increase the

shielding by covering the optical module and the power line filter with a metallic cover.

(4)

Vibration and shock

This module is plastic sealed and has its wire fixed by resin. This structure is relatively resistant to

vibration and shock. In actual equipment, there are sometime cases in which vibration, shock, or

stress is applied to soldered parts or connected parts, resulting in lines cut. A care must be taken in

the design of equipment which will be subject to high levels of vibration.

(5)

Attaching the fiber optic receiving module

Solder the fixed pins (pins 4 and 5) of the fiber optic receiving module TORX198 to the printed circuit

board in order to fix it to the board.

(6)

Shielding and wiring pattern of fiber optic receiving modules

To shield, connect the fixed pins (pins 5 and 6) of fiber optic transceiving module TORX198 to the

GND.

Where the fiber optic receiving module uses conductive resin, be careful that the case does not touch

wiring (including land).

To improve noise resistance, shield the optical module and the power line filter using a metallic cover.

(7)

Solvent

When using solvent for flux removal, do not use a high acid or high alkali solvent. Be careful not to

pour solvent in to the optical connector ports. If solvent is inadvertently poured in to them, clean it off

using cotton tips.

(8)

Protective cap

When the TORX198 is not in use, attach the protective cap.

(9)

Supply voltage

that supply voltage does not exceed the maximum rating value of 7 V, even for an instant.

(10) Output

If the receiver output is at low and is connected to the power supply, or if the output is high and is

connected to GND, the internal IC may be destroyed.