2N3498 Temperature-Power Derating Curve [2N3499, 2N3500, 2N3501]
NPN Switching Silicon Transistor. Package, TO-39, TO-5 metal Can.
2N3498 Applications; General purpose switching and amplifiers in high voltage circuits
2N3498 Transistor Derating Curve
The chart details the maximum allowable power dissipation with increasing ambient temperature. Maximum operational power dissipation is achievable at 25C. However above 25C the maximum package dissipation, or power, must be reduce to insure that the devices junction temperature remains constant. The higher the ambient temperature is increased the lower the allowable power dissipation, as depicted in the curves. The maximum allowable junction temperature is +2000C, or the point at which the device may not dissipate any additional power.
Related topics; Transistor Derating Curves & Transistor Manufacturers.
Temperature derating is a standard design practice for electrical engineers.
Refer to MIL-PRF-19500/366; Semiconductor Device, Transistor, NPN, Silicon, Amplifier, Types 2N3498, 2N3498L, 2N3498U4, 2N3499, 2N3499L, 2N3499U4, 2N3500, 2N3500L, 2N3500U4, 2N3501, 2N3501L, 2N3501UB, and 2N3501U4, to include JAN rated parts, [TO-39, TO-5]
2N3498 Maximum Ratings, Ta = 250C:
Collector Emitter Voltage = 100 volts dc
Collector Base Voltage = 100 volts dc
Emitter Base Voltage = 6 volts dc
Collector Current = 500mA dc
Power Dissipation 250C = 1 Watt
Operating Temperature = -65 to +2000C
Storage Temperature = -65 to +2000C
Editor note; In general the revision letter is removed from the document any time a military specification is reference on one of these the pages. The government controls the document and could change the revision level at any time, so listing the revision level doesn't provide any additional data. Of course the argument could be made that the revision level indicates when the graph was valid. However in most cases when a document undergoes an update, it's because of a minor change but the change still needs to be captured.
In any event, it's up to the user to insure that they use the most up to date specification available, including referencing the latest data sheet covering the device. Including reviewing the data sheet from the manufacturer which is supplying the device. Revision levels for components are always listed as they normally represent a similar-to but different device having different operational characteristics.
