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Items in specifications

Latest Updated:04/01/2008

Question:

Items in specifications

Answer:

The specifications of some products are customarily divided into absolute maximum ratings and electrical specifications or the absolute maximum ratings of some products are included in the electrical specifications. However, the meaning of the definition of each parameter is the same.

Absolute maximum ratings

Absolute maximum ratings must not be exceeded even momentarily for any parameter, since each parameter is independent from each other.

 

 

Operating (ambient) temperature (TA, Topt)

Temperature of usage environment in which normal operation can be guaranteed.
For discrete devices, since they do not have function circuits, the storage temperature Tstg is equivalent to the operating ambient temperature.

 

 

Junction temperature (operating junction temperature: TJ, Tj) and channel temperature (Tch)

The maximum permissible temperature for a semiconductor chip inside a package and is the sum of the operating ambient temperature and temperature raised by self-heating. This Junction temperature and the thermal resistance are used for calculating the power which a power semiconductor device can consume.

 

 

Storage temperature (Tstg)

The ambient temperature without bias (no voltage applied anywhere) at which breakage does not occur, for both standalone devices and mounted devices. Since voltage is not applied to any pins, the temperature of parts such as junctions and channels is the same as the ambient temperature.

 

 

Thermal resistance

Thermal resistance indicates the resistance to the conductivity of heat, and is expressed as the rise of the package temperature in unit power (see Thermal Design).
This thermal resistance and the Junction temperature are used for calculating the power which a power semiconductor device can consume.

 

 

Thermal resistance between junction and case (θj-c) and thermal resistance between channel and case (θch-c)

This value is thermal resistance from the semiconductor chip inside a package to the package (case) surface. It is used when a heat sink is attached to the semiconductor device. The chip temperature is calculated by adding the temperature raised by self-heating to the case temperature. This thermal resistance and the case temperature are used for calculating the power of a power semiconductor device which can be consumed.

 

 

Thermal resistance between junction and ambient (θj-a) and thermal resistance between channel and ambient (θch-a)

These are values that indicate how difficult it is for heat to be transferred from the semiconductor chip inside a package to ambient, and are used when the semiconductor device is used without a heat sink. The chip temperature is calculated by adding the temperature raised by self-heating to the operating ambient temperature. This thermal resistance and the operating ambient temperature are used for calculating the power that a power semiconductor device can consume.

 

 

DC characteristics
For digital ICs, in the condition that the input/output signal does not change (DC status), they are the voltage and current characteristics with respect to a high signal or low signal.
The output current is defined as a limit value at which the current flows to keep the output signal in the specified voltage range.
Leakage current is a very small amount of current that flows through the gate insulation film or channels in the off status of MOS devices.

 

AC characteristics
For digital ICs, they are time characteristics of the alternating (AC) input/output signal.
Period, width, transition time, delay between signals, and setup time/hold time are defined.
The load condition and test point are conditions under which these times are defined. Generally, the test point is the output voltage and input voltage of the DC characteristics.
In an overloaded state where the load condition is exceeded, since the time constants may increase, the AC characteristics may not be satisfied, and the input side may promote degradation by a through current if it is a CMOS. If the capacitance is overloaded, degradation may be promoted unless a circuit that counters the through current is provided.

 

Capacitance
Static capacitance between the input/output pin and GND of MOS devices or between both the pins of diodes.
This is defined, along with the DC characteristics, to verify adaptability of the output to the load condition and to judge the speed of the switching operation.

 

Recommended operating conditions

These are conditions recommended so that expected characteristics and operations can be obtained. A value into which the absolute maximum ratings of a semiconductor device such as a power transistor or a power FET derated can be used as long as they are within the recommended condition range. These conditions also serve as a rough standard for selecting a device.
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