Thyristor Semiconductor Products Page 79 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1008 I TIME di/dt (di/dt) C E 10% 63% V (dv/dt) Voltage across Triac E SOURCE I Figure AN1008.12 Waveshapes of Commutating dv/dt and Associated Conditions t gt : Gate-controlled Turn-on Time -- SCR and Triac The t gt is the time interval between the application of a gate pulse and the on-state current reaching 90% of its steady-state value. (Figure AN1008.13) As would be expected, turn-on time is a function of gate drive. Shorter turn-on times occur for increased gate drives. This turn-on inductive loading would restrict the rate-of-rise of anode current. For this reason, this parameter does not indicate the time that must be allowed for the device to stay on if the gate signal is removed. (Refer to the description of "IL: was resistive and equal to the rated load current value, the device definitely would be operating at a current above the dynamic latching current in the turn-on time interval since current through the device is at 90% of its peak value during this interval. 90% 10% 50% 10% On-state Current Rise Time Gate Trigger Pulse Delay Time Turn-on Time Gate Pulse Width Off-state Voltage 10% Figure AN1008.13 Waveshapes for Turn-on Time and Associated Conditions t q : Circuit-commutated Turn-off Time -- SCR The circuit-commutated turn-off time of the device is the time during which the circuit provides reverse bias to the device (negative anode) to commutate it off. The turn-off time occurs between the time when the anode current goes negative and when the anode positive voltage may be reapplied. (Figure AN1008.14) Turn-off time is a function of many parameters and very dependent on temperature and gate bias during the turn-off interval. Turn-off time is lengthened for higher temperature so a high junction temperature is specified. The gate is open during the turn- off interval. Positive bias on the gate will lengthen the turn- off time; negative bias on the gate will shorten it. I TM 50% I TM 50% I RM i R Reverse Current I D Off-State Leakage V D Off-State Voltage di/dt dv/dt t rr t q t 1 V T Figure AN1008.14 Waveshapes of t q Rating Test and Associated Conditions R JC , R JA : Thermal Resistance (Junction-to-case, Junction-to-ambient) -- SCR and Triac The thermal-resistance characteristic defines the steady- state temperature difference between two points at a given rate of heat-energy transfer (dissipation) between the points. The thermal-resistance system is an analog to an electrical circuit where thermal resistance is equivalent to electrical resistance, temperature difference is equivalent to voltage difference, and rate of heat- energy transfer (dissipation) is equivalent to current. Dissipation is represented by a constant current generator since generated heat must flow (steady-state) no matter what the resistance in its path. Junction-to-case thermal resistance establishes the maximum case temperature at maximum rated steady-state current. The case temperature must be held to the maximum at maximum ambient temperature when the device is operating at rated current. Junction-to-ambient thermal resistance is established at a lower steady-state current, where the device is in free air with only the external heat sinking offered by the device package itself. For R JA, power dissipation is limited by what the device package can dissipate in free air without any additional heat sink: T J -T C R JC = P (AV) T J -T A R JA = P (AV) Explanation of Maximum Ratings and Characteristics for Thyristors (continued)

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