## SUMMARY: AT655S28 Thyristor/SCR Datasheet Analysis

This document provides a comprehensive datasheet for the AT655S28 Thyristor (also known as an SCR - Silicon Controlled Rectifier). Here's a breakdown of the key specifications and information contained within:

1. Core Characteristics:

️· Voltage & Current Ratings: Designed for high-voltage and current applications, with a Repetitive Peak Reverse Voltage (VRRM) of 2800V and a Surge On-State Current (ITSM) of 30kA.
️· Operating Junction Temperature: Can operate up to 125°C, with a minimum operating temperature of -30°C.
️· Gate Triggering: Requires a Gate Trigger Voltage (VGT) of 3.5V and a Gate Trigger Current (IGT) of 300mA.
️· Thermal Resistance: Designed with Thermal Resistance of 21°C/kW.

2. Key Electrical Parameters:

️· On-State Voltage (VT): At 2900A, the on-state voltage is 1.8V.
️· Holding Current (IH): 300mA, the current below which the SCR will turn off.
️· Latching Current (IL): 700mA, the minimum current required to reliably maintain conduction.
️· Reverse Recovery Charge(Qrr): Data Not provided but it is an important parameter to consider.

3. Dynamic Characteristics:

️· Turn-off Time (tq): 320µs, representing the time it takes to turn off the SCR.
️· Rate of Rise of Off-State Voltage (dv/dt): 500 V/µs, the maximum rate of voltage change the SCR can withstand in the off-state.
️· Rate of Rise of On-State Current (di/dt): 200 A/µs, the maximum rate of current change the SCR can handle during turn-on.

4. Thermal Management:

️· Mounting: Requires a mounting force of 22.0/24.5 kN for adequate heat dissipation.
️· Thermal Resistance: Designed with Thermal Resistance of 21°C/kW and 6°C/kW (Junction to Case).

5. Graphical Data:

️· Dissipation Characteristics: Shows the relationship between forward current and junction temperature for both square and sine wave applications.
️· On-State Characteristic: Shows the voltage and current relationship at 125 degrees.
️· Transient Thermal Impedance: Graph showing thermal behavior.
️· Surge Characteristic: Shows the surge current capability vs. cycles.

6. Mechanical Specifications:

️· Cathode Terminal Type: DIN 46244 – A 4.8 – 0.8
️· Gate Terminal Type: AMP 6598-1

Overall:

The AT655S28 is a robust high-power Thyristor suitable for applications like industrial rectifiers, motor control, and high-voltage DC transmission where high blocking voltage, surge current capability, and reliable operation are critical. The datasheet provides all the necessary information for proper design, thermal management, and application of this device.