2N2222A Transistor Derating Curves

2N2222 NPN Transistor

2N2222A Temperature-Power Derating Curve, Case Mounted
NPN General Purpose Silicon Transistor. Package, TO-18 metal Can.
2N2222A: Application; Medium power amplifier and transistor switch

2N2222A Case Mounted TO18 Package Temperature-Power Derating Curve
Temperature Derating Curve for 2N2222A Transistor

Use the Graph to determine how much to derate power based on Case Temperature of a 2N2222 in a TO-18 package. For best results engineer the design to use one of the two lower 'gray' lines. Or design the circuit to operate near the lower lines, but parallel to them. The third curve represents the maximum power dissipation possible in a circuit. The top most curve represents component break-down [How to Read Transistor Derating Curves].
Additional Transistor Derating Curves covering different transistor types.
Temperature derating is a standard design practice for electrical engineers.

Refer to MIL-PRF-19500/255W; Semiconductor, Transistor, NPN, Switching, Types 2N2221A, 2N2221AL, 2N2222A, 2N2222AL, 2N2221AUA, 2N2222AUA, 2N2221AUB, 2N2222AUB, 2N2221AUBC, and 2N2222AUBC, JAN qualified, [TO-18]

2N2222A Maximum Ratings:
Collector Emitter Voltage = 50 volts dc [Vceo]
Collector Base Voltage = 75 volts dc [Vcbo]
Emitter Base Voltage = 6 volts dc [Vebo]
Collector Current = 800mA dc [Ic]
Power Dissipation 250C = 500mW
Operating Temperature = -65 to +2000C

To achieve higher temperature operation with a particular current drain use forced air or attach a heatsink; Heat Sink Manufacturers [Clip-on style heat sinks].
The derating curve represents free, still air. The 2N2222 is operated with out a fan and not placed in a case, so air is allowed to move freely around the component.

Case mount. A type of package (outline) which provides a method of readily attaching one surface of the semiconductor device to a heat dissipater to achieve thermal management of the case temperature. This device has the collector internally connected to the case.

Case temperature. Case temperature is that temperature measured at a specified point on the case of a semiconductor device.

The 2N2222 Transistor or the 2N2222A transistor in this package style are one of the most common transistor amplifiers.

How to Derate; Guideline for Derating Electronic Components.

2N2222 Switching Test

The first circuit, shown below, tests saturated turn-on time, while the second circuit tests saturated turn-off time for a 2N2222 transistor. Note that the first circuit schematic takes the output from the collector, which is pulled high to Vcc. While the second schematic takes its output from a resistor divider circuit. Also note that the bias voltage changes between the two schematics. The maximum Collector-to-Emitter voltage is 40 volts, but the circuit voltages uses 30 volts. Although there is no note in the schematic, use non-inductive resistors so the rise and fall times are not effected but the inductance of the resistors.

2N2222 Saturated turn-on and turn-off test setup schematic
2N2222A Saturated Switching Time Test

Schematic Notes:
The rise time (tr) of the applied pulse shall be = 2.0 ns, duty cycle = 2 percent, and the generator source impedance shall be 50 Ohm. Sampling oscilloscope: ZIN = 100 k ohm, CIN = 12 pF, rise time = 5 ns.

The output waveform is 'rounded' because the transistor is in saturated. When a transistor is in saturated it takes longer for it to come out of saturation or switch. So a pulse edge applied to a transistor in saturation is slowed on the output, in this case inverted as well. The T-on time is the value being measured with this circuit. The pulse width is shortened or degraded as the rise and fall time is increased and invades the pulse width time.

For a 2N2222 the input rise time should be set at less than or equal to 2nS. The pulse width is of less importance but remains as shown at 200nS. Note that although no power supply by-pass capacitors are shown, filtering capacitors should be used to filter noise from the supply during the test.
Although the package type is of little importance for this test, the derating curves for the 2N2222 use a TO-18 metal Can. The test circuit is some what generic, so basically any transistor could use the circuit set-up [using the correct Vcc].

Both the 2N2222A transistor and the 1N916 diode are in full production and available for purchase. The 2N2222 is a very common NPN general purpose transistor which has been in service for many years. The 1N916 is also a very common small signal diode in a DO-35 package.

TO-18 Package Style
TO-18 Package

Lead 1= Emitter
Lead 2 = Base
Lead 3 = Collector

Related 2N2222 Curves
TO-18 Case Dimensions
2N2222, Adhesive Mount SMD
2N2222, TO-18 Lead Mounted

Transistor Manufacturers
BJT Case styles


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Modified 1/21/12
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