2N5153 Transistor Derating Graph

2N5153 Temperature-Power Derating Curve [2N5151]
PNP Switching Transistor. Package, [TO-205 metal can].
2N5153 Applications; High-speed switching, Low Power

2N5153 Transistor Temperature-Power Derating Curves

2N5153 Derating Equation;
Derate linearly by 5.7mW/⁰C above an ambient temperature of 25⁰C
Derate linearly by 66.7mW/⁰C above a case temperature of 25⁰C
The derating curve applies to a 2N5151 PNP transistor as well.

The derating graph details the maximum allowable power dissipation with 2N5153 case temperature. Maximum operational power dissipation is achievable at 25⁰C [or below]. However above 25C the maximum package dissipation must be reduce to insure that the devices junction temperature remains constant.
Heat Sink;
Installing a [clip-on] heat-sink is one method of insuring that the device will operate above the ambient temperature depicted in the curves. Decreasing a components operational limits as temperature is increased is called derating.
Air Flow;
Implementing forced air cooling will also allow the 2N5153 to operate higher that the graph represents, as the power derating curves are for free-air. Free-Air or still-air is air surrounding the device that is not forced [via a fan] or inhibited because the device in placed within a chassis [enclosure] or case.
Altitude;
An additional power reduction must also be accounted for if the 2N5153 is operated above sea-level. Check the manufacturers data sheet for operation above the altitude of 10,000 feet [or above sea-level].
Heat Sources;
Insure that there are no adjacent heat sources which may be producing radiant heat, the graph does not account for heat produced from other sources.

Refer to MIL-PRF-19500/545G; Semiconductor Device, Transistor, PNP, Silicon, Power, Types 2N5151, 2N5153, 2N5151L, 2N5153L, 2N5151U3, and 2N5153U3, JAN, JANTX, JANTXV, JANS, JANHC, AND JANKC, JANSM, JANSD, JANSP, JANSL, JANSR, JANSF, JANSG, JANSH, JANHCB, JANHCC, JANKCB, JANKCC, JANKCCM, JANKCCD, JANKCCP, JANKCCL, JANKCCR, JANKCCF, JANKCCG, and JANKCCH [TO-39 Metal Can]

Note; links to the alternate surface mount packages to the left.
The 2N5151 is available in a TO-205 package [metal can], Similar to a TO-39.
Screening and processing per MIL-PRF-19500 appendix E

Ambient temperature. is the air temperature measured below a semiconductor device, in an environment of substantially uniform temperature, cooled only by natural air convection [free-air], and not materially affected by reflective and radiant surfaces [adjacent devices].

Case temperature. is that temperature measured at a specified point on the case of a semiconductor device. Note that the curves shown above relate to the 2N5151's case temperature

Storage temperature [Tstg]. Storage temperature is a temperature at which the device may be stored without any power being applied. Storage temperature for the 2N5153 transistor ranges between -65 to +200⁰C.