TOTX1960(F) Toshiba, TOTX1960(F) Datasheet - Page 14

• Manufacturer Part Number: TOTX1960(F)
• Manufacturer: Toshiba

Specifications of TOTX1960(F)

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Precautions for Using TOSLINK
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1. Absolute Maximum Rating
The absolute maximum ratings are the limit values that must not be exceeded during device operation. Any one of them must not be exceeded.
Otherwise, the device characteristics may become unrestorable or the device may be permanently damaged in the worst case.
2. Operating Ranges
The operating range is the range of conditions necessary for the device to operate as specified in individual technical datasheets and databooks.
Even if a device is operated within the absolute maximum ratings, functional operation of the device or the specifications related to electrical
characteristics may not be guaranteed beyond the conditions indicated under “Operating Ranges.”
Exposure to conditions in excess of these ranges may also affect device reliability. Thus, special precautions are necessary in designing
electronic systems. For higher reliability, operating ranges should be derated for current, power and temperature.
3. LED Lifetime
Over a long period of time, the performance of an optical module will gradually be degraded, mostly be due to the lowering of the fiber output
power (Pf). This is caused by the degradation of the optical output of the LED used as the light source. Its cause may be a wafer crystallization
defect or mold resin stress, but no detail has been elucidated yet.
The lifetime of an LED is greatly influenced by the operating and environmental conditions in which it is used, as well as by the lifetime
characteristics specific to the device type. Thus, once the type of the LED and the operating conditions have been determined, it is
recommended to evaluate the lifetime characteristics.
Depending on the environmental conditions, Toshiba recommends that maintenance be performed regularly, including the checking of optical
output.
4. Soldering
Optical modules use semiconductor devices but are essentially optical components. When soldering, ensure that flux does not adhere
to the light-emitting or light-receiving surfaces.
Take the same care when cleaning off flux after soldering.
Some optical transceiver modules include a protective cap. This cap is intended to prevent accidental operation when the module is not
in use. It is not dust- or waterproof. Because the optical module is an optical component, Toshiba does not recommend soldering
methods or post-solder flux cleaning methods in case where flux could affect the module. Toshiba recommends first soldering without
mounting the module, then cleaning the PCB. The module should then be hand-soldered and no subsequent cleaning should be
performed.
If it is not possible to hand-solder the module, one way of avoiding the effects of flux is to use non-halogen (chlorine-free) flux, taking
care not to leave chlorine or other residue, and omitting the post-solder cleaning. In such cases too, the reliability of the device must be
checked. Be sure to check the reliability of the device.
5. Noise Resistance
The case for the TOSLINK optical receiving and transceiver modules is made of conductive plastic. The case is designed to provide
shielding against noise when the reinforcing pin at the front of the module is grounded. When the module is used, this pin should be
connected to the signal ground.
Since the case for the optical receiving and transceiver modules has a resistance of several tens of ohms, ensure that the case does
not touch the power line or any other circuits.
Generally, the use of optical transmission devices is considered to improve noise resistance.
While optical fibers are certainly not affected by noise, optical modules, particularly receiver modules, are comparatively easily affected
by noise because they handle such minute current signals.
To improve noise resistance, the TOSLINK case is treated to make it conductive. However, since the signal output from the optical
receiving module’s photodiode is a minute current signal, in some environments simply shielding the case will not protect against noise.
When using a TOSLINK device, conduct live tests to check noise resistance.
A simple noise filter is mandatory for the power lines for the TOSLINK optical receiving module and optical transceiver module.
However, in the case of significant power supply ripples, further filter reinforcement is also necessary. In addition, when the optical
module is placed in a location susceptible to emission noise, Toshiba recommends covering the optical module and power supply filter
with a metal cover to enhance the shielding.
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