Safety Precaution

1. Using Firstsilicon Semiconductors Safety

Firstsilicon is continually working to improve the quality and reliability of its products. Nevertheless, semiconductor devices in general can malfunction or fail due to their inherent electrical sensitivity and vulnerability to physical stress. It is the responsibility of the buyer, when utilizing Firstsilicon products, to observe standards of safety, and to void situations in which a malfunction or failure of a Firstsilicon product could cause loss of human life, bodily injury or damage to property. In developing your designs, please ensure that Firstsilicon products are used within specified operating ranges as set forth in the most recent products specifications. Also, Please keep in mind the precautions and conditions set forth in the Firstsilicon semiconductor Reliability Handbook.

2. Storage

(1) Avoid storage locations where devices will be exposed to moisture or direct sunlight.

(2) Follow the instructions printed on the device cartons regarding transportation and storage.

(3) The storage area temperature should be kept within temperature ranges of 5 °C to 35 °C, and relative humidity should be maintained at between 45% and 75%

(4) Do not store devices in the presence of harmful (especially corrosive) gases, or in dusty conditions.

(5) Use storage areas where there is minimal temperature fluctuation. Rapid temperature changes can cause moisture to form on stored devices, resulting in lead oxidation or corrosion. As a result, the solderability of the leads will be degraded.

(6) Do not allow external forces or loads to be applied to device while they are in storage.

(7) If devices have been stored for more than two years, their electrical characteristics should be tested and their leads should be tested for ease of soldering before they are used.

3. Design

Care must be exercised in the design of electronic equipment to achieve the desired reliability. It is important not only to adhere to specifications concerning absolute maximum ratings and recommended operating conditions, it is also important to consider the overall environment in which equipment will be used, including factors such as the ambient temperature, transient noise and voltage and current surges, as well as mounting conditions which affect device reliability. This section describes some general precautions which you should observe when designing circuits and when mounting devices on printed circuit boards. For more detailed information about each product family, refer to the relevant individual technical datasheets available from Firstsilicon.

3.1 Absolute maximum ratings

Do not uses devices under conditions in which their absolute maximum ratings (e.g. current, voltage, power dissipation or temperature) will be exceed. A device may break down or its performance may be degraded, causing it to catch fire or explode resulting in injury to the user. The absolute maximum ratings are rated values which must not be exceeded during operation, even for an instant. Although absolute maximum ratings differ from product to product, they essentially concern the voltage and current at each pin, the allowable power dissipation, and the junction and storage temperatures. If the voltage or current on any pin exceeds the absolute maximum ration, the device's internal circuitry can fuse wiring or cause the semiconductor chip to break down. If storage or operating temperature exceeds rated values, the package seal can deteriorate or the wires can become disconnected due to the differences between the thermal expansion coefficients of the materials from which the device id constructed.

3.2 Derating

When incorporating a device into your design reduces its rated absolute maximum voltage, current, power dissipation and operating temperature in order to ensure high reliability. Since derating differs from application to application, refer to the technical datasheets available for the various devices used in your design.

4. Safety standards

Each country has safety standards which must be observed. These safety standards include requirements for quality assurance systems and design of device insulation. Such requirements must be fully taken into account to ensure that your design conforms to the applicable safety standards.

5. Soldering temperature profile.

The soldering temperature and heating time vary from device to device. Therefore, when specifying the mounting conditions, refer to the individual datasheets and databooks for the devices used.

6. Flux cleaning

(1) When cleaning circuit boards to remove flux, make sure that no residual reactive ions such as Na or Cl remain. Note that organic solvents react with water to generate hydrogen chloride and other corrosive gases which can degrade device performance.

(2) Washing devices with water will not cause any problems. However, make sure that no reactive ions such as sodium and chlorine are left as a residue. Also, be sure to dry devices sufficiently after washing.

(3) Do not rub device markings with a brush or with your hand during cleaning or while the devices are still wet from the cleaning agent. Doing so can rub off the markings

(4) The dip cleaning, shower cleaning and steam cleaning processes all involve the chemical action of a solvent. Use only recommended solvents for these cleaning methods. When immersing devices in a solvent or steam bath, make sure that the temperature of the liquid is 50 °C or below, and that the circuit board is removed from the bath within one minute.