TORX178S Datasheet, PDF (3/4 Pages) Toshiba Semiconductor – FIBER OPTIC RECEIVING MODULE

TORX178S
6. Required Optical Fiber with Fiber Optic Connectors
TOCP172−□□B
7. Precautions 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.
For 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 pin (pin 4 and 5) of the fiber optic receiving module TORX178S to the printed circuit
board in order to fix it to the board.
(6) 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.
(7) Protective cap
When the TORX178S is not in use, attach the protective cap.
(8) Supply voltage
Use the supply voltage within the recommended operating condition (VCC = 5 ± 0.25 V). Make sure
that supply voltage does not exceed the maximum rating value of 7 V, even for an instant.
(9) Interface
The TORX178S has a TTL interface. It can be interfaced with any TTL−compatible C−MOS IC.
(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.
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