Absolute Maximum Ratings

The absolute maximum ratings are defined as the allowable limits that should not be exceeded, even instantaneously. If one or more of these values are exceeded, the semiconductor device will break. Therefore, it is required to design electronic devices that use semiconductors so that the stress exceeding the values is not applied to semiconductors even instantaneously.
Absolute maximum ratings do not guarantee reliability. Even within the absolute maximum ratings, if the recommended conditions are exceeded, their durability decreases and as a result, semiconductors may not withstand long-term use.
Typical characteristics of the absolute maximum ratings listed in the IGBT data sheet are shown below. The parameters of absolute maximum ratings listed depend on the type of IGBTs.

Electrical Characteristics

Electrical characteristics show the performance of a product by specifying conditions such as temperature, voltage, and current.
The following are typical parameters of electrical characteristics described in the data sheet. The parameters of electrical characteristics to be listed depend on the type of IGBTs.

Thermal Characteristics

The following are typical parameters of thermal characteristics described in the data sheet. The parameters of thermal characteristics to be listed depend on the type of IGBTs.

Static Characteristics

This section describes the typical static characteristics of IGBTs.

I_C－V_CE Characteristics

The following figure shows an example of characteristics of the collector current, I_C, and the collector-emitter voltage, V_CE, at each gate voltage, V_GE. I_C－V_CE characteristics are also called the output characteristics. Due to the structure of IGBTs, a PN junction is generated between the collector and emitter. When the junction potential of the PN junction (V_CE = 1.5 V in this characteristic example) is exceeded, the I_C starts to flow. The higher the V_GE, the lower the V_CE when the specified I_C is flowing. To reduce conduction loss (I_C×V_CE), set the IGBT in a region where V_CE(SAT) changes are small (generally gate voltage is about 15 V).

I_C－V_GE Characteristics

The following figure shows an example of characteristics of the collector current, I_C, and the gate-to-emitter voltage, V_GE.
In this characteristic example, in the region of V_GE < 10 V, the higher the junction temperature, T_J, the lower the V_GE when the specified I_C is flowing (negative temperature coefficient). Conversely, in the region of V_GE ≥ 10 V, the higher the junction temperature, T_J, the higher the V_GE when the specified I_C is flowing (positive temperature coefficient). To prevent the permanent damage due to heat generation, it is recommended to use the IGBT in the region of positive temperature coefficient.

V_GE(TH)－T_J Characteristics

The following figure shows an example of characteristics of the gate threshold voltage, V_GE(TH), and the junction temperature, T_J.
The higher the T_J, the lower the V_GE(TH) (negative temperature coefficient). When the circuit operates and the IGBT temperature becomes high, the IGBT turns on at a low gate voltage. Therefore, changes in V_GE(TH) due to temperature characteristics must be taken into account in designing the circuit in order to avoid malfunction due to noise.

Capacitance Characteristics (C_ies, C_oes, C_res)

As shown in the following figure, due to the structure of IGBTs, parasitic capacitances (C_GC, C_GE, C_CE) are generated. These parasitic capacitances affect the switching characteristics.

Input Capacitance, C_ies

Input capacitance, C_ies, affects the delay time. The larger the C_ies, the longer the turn-on delay time, t_d(ON), and the turn-off delay time, t_d(OFF), because a large amount of charge must be charged/discharged at the IGBT turning on/off. In addition, the larger the C_ies, the larger the power loss. Therefore, the IGBT with small C_ies is ideal.
C_ies is calculated by the following equation.

Output Capacitance, C_oes

The output capacitance, C_oes, affects the turn-off characteristics. When the C_oes is large, the voltage change rate, dv/dt, of the collector-to-emitter voltage, V_CE, is reduced at the IGBT turn-off, resulting in reducing the influence of noise but increasing the turn-off fall time, t_f.
C_oes is calculated by the following equation.

Reverse Transfer Capacitance, C_res

Reverse transfer capacitance, C_res, is also called mirror capacitance.
C_res affects the high frequency characteristics. The larger the C_res, the more the following characteristics appear.

• The fall time of collector-to-emitter voltage, V_CE, at turn-on is long
  (The turn-on rise time, t_r is long)
• The rise time of collector-to-emitter voltage, V_CE, at turn-off is long
  (The turn-off fall time, t_f, is long)
• Reverse transfer capacitance, C_res, is calculated by the following equation.

Charge Characteristics (Q_G, Q_GE, Q_GC)

Total gate charge, Q_G, gate-to-emitter charge, Q_GE, and gate-to-collector charge, Q_GC, are the charges required to drive the IGBT. These affect the switching characteristics. The smaller the value, the smaller the power loss, and the fast switching is achieved.

Switching Characteristics (t_d(ON), t_r, t_d(OFF), t_f)

The following figure shows the measurement circuit of switching time.

The following figure shows the switching waveforms.

Turn-on Delay Time, t_d(ON)

Time from 10% of the V_GE setting value to 10% of the I_C setting value

Turn-on Rise Time,t_r

Time from 10% to 90% of the I_C setting value

Turn-on Time, t_ON

The total time of t_d(ON) and t_r

Turn-off Time, t_d(OFF)

Time from 90% of the V_GE setting value to 90% of the I_C setting value

Turn-off Fall Time,t_f

Time from 90% to 10% of the I_C setting value

Turn-off Time, t_OFF

The total time of t_d(OFF) and t_f

Short-circuit Characteristics

Short-circuit current, I_SC, is the current that flows when an IGBT is shorted. The higher the gate-to-emitter voltage, V_GE, the higher the short-circuit current, I_SC, thus causing the short circuit withstand time, t_SC, to be decreased. The higher the junction temperature, T_J, the lower the t_SC.

Fast Recovery Diode

Unlike power MOSFETs, IGBTs do not have body diodes. When using an IGBT to control an inductive load such as a motor, using a product that combines an IGBT and a fast recovery diode (FRD) in one package reduces the number of external components, resulting in reliability improvement of the circuit. Click here for the features of the fast recovery diode.