TOTX178A

The TOTX178A is a fiber optic transmitting module for digital audio interface.If an optical module is used for a long period of time, degeneration in the characteristics will mostly be due to a lowering of the fiber output power (Pf).This is caused by the degradation of the optical output of the LEDs used as the light source. The cause of degradation of the optical output of the LEDs may be defects in wafer crystallization or mold resin stress.The detailed causes are, however, not clear.

The TOTX178A has the following features including:(1)conforms to EIAJ standard CP-1201(for digital audio interfaces including fiber optic inter-connections);(2)LED is driven by differential circuit;(3)TTL interface;(4)a self-tapping hole for easy attachment to audio equipment panels.The lifetime of light emitters is greatly influenced by the operating conditions and the environment in which it is used as well as by the lifetime characteristics unique to the device type.Thus, when a light emitting device and its operating conditions determined, Toshiba recommend that lifetime characteristics be checked.

The absolute maximum ratings of the TOTX178A are:(1)storage temperature:-40 to 70; (2)operating temperature:-20 to 70; (3)supply voltage:-0.5 to 7V; (4)input voltage:-0.5 to Vcc+0.5V; (5)soldering temperature:260.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.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.