AN320 STMICROELECTRONICS | Alldatasheet
Document overview
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Technical content
(or Triac in the bidirectional version). STMicroelectronics has developed this type of component under the trade name of Trisil. This Application note describes the operation of the Trisil. Figure 1. I / V characteristic of a Trisil
1 Trisil characteristics
1.1 Electrical characteristic
the component has only two terminals.
1.2 Operation seen from the outside
- Leakage current
- Electrical capacity
- Reliability of the component in blocking mode
Figure 2. Stand by characteristics identical to that of a Transil diode (see Figure 3). BO) and the time for switching between the blocked and conducting states.
Figure 5. Return to standby operation the triggering of the thyristor structures take place. capacity to divert currents much higher than those possible for an avalanche diode (Transil). Furthermore, this limitation is independent of the avalanche voltage of the device.
1.3 Limiting property
Figure 6. Correlation between the voltage and the surge current Figure 7. Correlation between the limiting voltage and the surge voltage ramp
1.4 Behavior in case of current surges
of the component depends on the external circuit.
- Tj: instant temperature at the junction level
- TA: ambient temperature
- ZTH: transient thermal impedance (as a function of the duration of the pulse)
- VON: voltage across the terminals of the component in the conducting state
- IRS: transient current flowing through the component This equation clearly shows the advantage of the Trisil. A decrease in the voltage across its terminals enables it to conduct a much higher current than the avalanche diode for the same junction temperature. Since the voltage to be taken into consideration for the calculation is that in the conducting state, the permitted current levels in transient operation are independent of the avalanche voltage and the guaranteed values are identical for all the types of a given series (see Figure 8).
Figure 8. Comparison of the limited transient currents for a Transil and a Trisil in
Figure 9. Long duration overload test
1.5 Response time
1.6 Operation within the avalanche area
between the blocked state and the conducting state at low VON.
- Maximum junction temperature which is now that given by the catalogue, i.e. 150 °C
- Voltage which is that of the avalanche mechanism
- Continuous thermal resistance replacing the transient thermal impedance In AC operation, although Equation 2 still holds good, the voltage-current diagram as a function of time shown in Figure 10 is clearer. t(s) I(A) –10 F = 50 Hz 10 pair of pulses 112112 180
2 Physical operation
Figure 12. Operation in the blocked mode
Figure 13. Operation in the avalanche mode 2). The side current biases the P1 layer next to the N1 part of the emitter. same potential as the N1 region by metallization.
Figure 14. Thyristor effect of the Trisil
0.6 V, a value which is sufficient to create injection of electrons from the cathode towards the
1 area and thus trigger thyristor N1 P1 N2 P2. effect of the electrical field operating in the space charge of the reverse biased J2 junction. N1, this time resulting in the injection of electrons from N1 to P1. act as a forward biased junction and the voltage across the component will drop.
3 Revision history
Table 1. Document revision history February-1998 1 First issue. 10-May-2004 2 Stylesheet update. No content change. 05-Jul-2010 3 Updated trademark statements.