Transistor

What are the thermal resistance values of the 2SA1546?

Rth(j-a) = 96.15°C/W
Rth(j-c) = 17.86°C/W
Reference: The thermal resistance between a junction and the ambient air can be calculated by this expression:

( Tjmax - Ta ) / PT = ( 150 [°C] - 25 [°C] ) / 1.3 [W] = 96.15 [°C/W]

The surface temperature of the case reaches 80°C when the total power dissipation of the 2SD1899-Z (MP-3) is 1.0 W.
At this time, what is the junction temperature?

The Rth(j-c) thermal resistance between the junction and case of the 2SD1899-Z (MP-3) is 12.5°C /W.
Where the case temperature is 80°C and the total power dissipation is 1.0 W, therefore, the junction temperature can be calculated by the following expression.

80 [°C] + 12.5 [°C/W] * 1.0 [W] = 92.5 [°C]

At what temperature must the case temperature of the 2SC4553 be maintained to prevent the junction temperature from exceeding 150°C at an ambient temperature of 55°C?

The thermal resistance between the junction and case is used to estimate the junction temperature from a measured case temperature.
The thermal resistance between the junction and case of the 2SC4553 is 4.2°C/W.
For example, the temperature difference between the junction and the case when the 2SC4553 is used at a total power dissipation of 10 W is 4.2°C × 10 W = 42°C as the thermal resistance between the junction and case = 4.2°C/W.
This means that the case temperature must be 150°C - 42°C = 108°C or less because the temperature difference between the junction and case is 42°C when the transistor is used at 10 W.
The junction temperature is therefore not directly related to the ambient temperature because it is estimated by measuring the case temperature. If the ambient temperature rises, however, the case temperature rises accordingly. Thus, the total power dissipation must be decreased so that the junction temperature does not exceed 150°C.

Related item: Thermal design

(2008/02)

Data of the VBE at low temperatures and at high temperatures are not shown in the Data Sheet.
What are the temperature characteristics of the VBE?

The temperature characteristics of the VBE are determined by the temperature coefficient of the PN junction ( 2 mV/°C).

How much does the collector cutoff current I_CBO change according to the temperature?

I_CBO doubles for every 10°C (approx.) rise in temperature.

(2006/03)

What are the temperature characteristics of h_FE?

The temperature characteristics of h_FE are (approx.) 0.5 to 1.5%/°C. When designing your circuit, be sure to make allowances for a drop in h_FE, especially at low temperatures.

(2006/03)

What are the marking indications on self-standing packages?

Markings on power-type packages such as the TO-220 and small-signal-type packages such as the TO-92 are as follows.

• Power-type packages
  Top line: NEC logo
  Middle line: Marking name (The marking name is the part number minus "2S".)
  Lower line: Rank, lot number (See details below.)

• Small-signal-type packages
  The marking contents of small-signal-type packages are the same as those on power-type packages except that the NEC logo is omitted.

What is a product with marking "L4"?

It is 2SC1623 transistor.
A hfe rank name is marked on three-pin mini-mold package products such as the 2SC1623 because a small package is used.

Reference:2SC1623 hfe rank

Marking	L4	L5	L6	L7
hfe	90 to 180	135 to 270	200 to 400	300 to 600

The absolute maximum rating of the base current of a small signal transistor is not defined.
How much current is allowed to flow?

Generally, the maximum rating of Ib is Ib ≤(1/10)Ic.
Check the base current based on the absolute maximum rating of the collector current.

Are there any recommended mount pads for surface mount transistors?

The pads differ depending on the package, so please go to the following Web site and click the mount pad for the relevant package.
http://www.necel.com/discrete/en/package/smd.html

For the RF & microwave devices, refer to PACKAGE LINE-UP FOR RF AND MICROWAVE DEVICES on the following page (also for CAD data).
http://www.ncsd.necel.com/microwave/english/document.html#pkg

(2007/04)

What are the requirements (required characteristics), guaranteed values, and permissible values for elements to guarantee complementary use?

Even if complementary use is recommended, no particular guarantee items are set. Generally, a requested complementary characteristic item is the DC amplification rate (hFE), which is a current characteristic.
Other requested characteristic items for the designed circuit may differ. Therefore, in the case of complementary use, please compare the various characteristics and make your judgment accordingly.

Are the collector capacitance (Cob), transition frequency (fT), etc., correlated with the hFE rank as transistor characteristics?

Generally, hFE and collector capacitance (Cob) are not correlated.
On the other hand, the transition frequency (fT) becomes lower if hFE declines because the current gain decreases as hFE decreases.

When using a transistor for amplification, about how long are the turn-on and turn-off times?

An amplification transistor is not used for switching, so these times are not prescribed. If you need switching characteristics, please use a switching transistor.

(2007/11)

How many volts is the withstand voltage for the 2SC1623's Vceo reverse voltage?

The reverse voltage of the Vceo is not prescribed, but in the case of the 2SC1623, it is approximately the absolute maximum rating of 5 V for Vebo as a rough guide.

The 2SC4176 data sheet lists the absolute maximum ratings Vces = 40 V and Vceo = 15 V. What is the difference between the two?
Which should actually be applied as the maximum voltage between the collector and emitter?

Taking the rated voltage as an example for the voltage rating method, the voltage is applied between the collector and emitter using the emitter as the reference, and rated according to the base pin status.
In other words, Vceo (Fig. 1) is the rating between the collector and emitter for base open, and Vces (Fig. 2) is the rating between the collector and emitter when a short circuit is established between the base and emitter.
Since the relationship between Vceo and Vces is Vceo < Vces, safety is achieved by complying with the lowest of the two, Vceo.

(2006/10)

The data sheet indicates that some products are for low-frequency amplification or some are for high-frequency amplification; how can you clarify the specific frequency range for these classifications?

There is no strict classification, but low-frequency elements are generally for amplification in the several tens of hertz to several tens of kilohertz frequency area, i.e., the range used in audio and musical instrument applications.
High-frequency elements are assumed to amplify signals in the range of several tens of kilohertz to several hundred megahertz.
Incidentally, elements that amplify signals of 1 GHz or higher are known as ultra-high frequency elements.

(2006/03)

What is the electrostatic tolerance of a bipolar transistor (Human Body Model (HBM) and Machine Model (MM))?

Electrostatic tolerance is not specified for transistors.
In Japan, information on electrostatic tolerance can be found in NEC Electronics Reliability Report available from NEC Electronics distributors. In the other areas, please inquire it to an NEC Electronics branch near you.
For information on the Human Body Model (HBM) and Machine Model (MM), please refer to 6.4 Cautions on ESDs (Electrostatic Discharges) in the Review of Quality and Reliability Handbook.

(2006/07)

I have heard that hFE degradation occurs during extended use.
What causes hFE degradation, and are there any countermeasures?

h_FE degradation may occur due to prolonged use of circuits in which a voltage near or exceeding the reverse bias breakdown voltage (emitter-base voltage V_EBO) is repeatedly applied, even momentarily, between the emitter and base of the transistor.
The circuit must be designed such that it does not cause reverse bias breakdown between the emitter and the base.

(2007/11)

The following characteristics graph of the transient thermal resistance vs. pulse width appears in the data sheet of the 2SC3632. What kind of thermal resistance is indicated by the "free air" and "infinite heat sink" curves?

The "free air" curve indicates the junction-ambient transient thermal resistance, and the "infinite heat sink" curve indicates the junction-case transient thermal resistance.
The rightmost value on the curve (pulse width = 100 s) means the steady-state thermal resistance value.

(2008/01)

The transient thermal resistance graph for the 2SA1396 states that the total power dissipation conditions are "T_A = 25°C, no heat sink".
Under what mounting conditions does this apply? Presumably the board would have to be of a certain size.

"T_A = 25°C without heat sink" is the specification in the case of self-standing (vertical insertion) mounting on the board without heat sink, as shown in the figure.
In this case, there is actually little heat dissipation to the board, so that there are no particular requirements regarding board size.

(2007/02)

The 2SA1412 data sheet describes the power dissipation characteristics with heat sink as shown in the figure below. What are the heat sink models that can be used and how should they be attached?

NEC Electronics does not provide particular guidance regarding the recommended heat sink models and attachment methods.
Please inquire with the various heat sink manufacturers, based on your usage conditions being considered.

Related items
Power rating

(2007/03)

In the uPA2000 series, when connecting a relay or solenoid valve to the output side, should a surge-absorption diode be attached to both ends of the relay or solenoid valve coil?

As shown in the figure (A), a surge absorbing diode is included in the uPA2000 Series, so that basically no surge absorbing diode is required when connecting a relay or solenoid valve to the output side.
However, if surges exceeding the absolute maximum rating for the internal diode are assumed, external connection of a surge absorbing diode with a large loss capacitance is required.
Moreover, if no internal diode can be used due to differing power supply voltages as shown in the figure (B), and when driving a pulse motor in which a regenerative current occurs for a long period of time, because an internal diode is used principally for the purpose of spike voltage absorption, an external diode is required.

(2007/02)

Why does the total power dissipation P_T(T_C= 25°C) differ (20 W, 25 W, 30 W) for the 2SB1430, 2SB1431, 2SB1432, etc., although all these products use the same package (TO-220)?
Is this due to differences in chip size?
If so, why is the total power dissipation the same (2.0 W) in the case of P_T(T_A= 25°C)?

These differences in total power dissipation are due to differences in chip size.
Total power dissipation in the case of P_T(T_C= 25°C) is influenced by the chip size.
The larger the chip size, the more easily heat dissipation occurs, resulting in large total power dissipation.
In the case of P_T(T_A= 25°C), heat dissipation occurs almost completely from the package to ambient, and there is almost no influence of chip size on total power dissipation.

(2007/02)

Collector current I_C = 100 mA is listed among the absolute maximum ratings of the 2SA1611 and 2SC4177, but does this value apply equally to the collector current (direct current) and (pulse current)?
If not, then what are the respective absolute maximum ratings?

The absolute maximum rating for the collector current of the 2SA1611 and 2SC4177 describes the rating for direct current, and not that for pulse current.
Thus, users must ensure that the pulse collector current is used within this rating as well.

(2007/02)

What are the operating states of the following three operating regions of transistors: saturation region, active region, and cut-off region?

Saturation region:	As the base current increases, the voltage between both terminals of the load resistance (VRl = IC × Rl) becomes larger. In the figure below, a -> b on the load line. If the power supply voltage is constant, the collector current past c on the load line does not increase no matter how much the base current increases, and the voltage between the collector and the emitter is minimized. This minimum voltage is called the collector saturation voltage VCE (sat). The state of this region means that switch operation is on.
Active region:	The light blue region in the figure below is the region where the change of the input signal on which the center is set at point b of the load line, which is a suitable base current, can be amplified without distortion to a large collector current change.
Cut-off region:	Even if the base pin is not connected, collector cut-off current ICEO flows between the collector and emitter. This region is called the cut-off region (collector cut-off region). The state of this region means that switch operation is off.

Related item: Collector saturation voltage

(2007/03)

The uPA604T has two NPN transistor circuits. Can this product be used for differential amplifications?

Transistors for differential amplifications must be balanced electrically and thermally, but transistors that are designed for differential amplifications, including the uPA604T, are not available from NEC Electronics.

(2008/02)

How should the base current be calculated when a voltage of 4 V is applied to the base pin of the FA1L4L?

The base current of the FA1L4L is the current flowing through the base pin (B).
It is not the current flowing between the base and emitter of the internal transistor, but is the current including the base resistance R1 of 47 kΩ TYP.
As a rough estimate, the base current is about (4 V - 0.6 V)/47 kΩ = 72 uA.
The current value of base-emitter resistance R2 (22 kΩ TYP.) is about 0.6 V/22 kΩ = 27 uA.

(2008/02)