TIP120 Darlington transistor electrical specification
- TIP120 is an NPN Darlington pair transistor device
- Collector to emitter voltage is 60V
- Collector to base voltage is 60V
- Emitter to base voltage is 5V
- Collector current is 5A
- The Base current is 120mA
- Power dissipation is 65W
- DC current gain is 1000hFE
- Small signal DC current gain is 4hFE
- Junction temperature is between -65 to +150℃
- Collector to emitter saturation voltage (VCE (SAT)) is 2V to 4V
- Thermal resistance is 92℃/W
- High current
- Low saturation voltage
TIP120 transistor Pinout
|The base is the trigger for the transistor
|Current flows through the collector
|Current flows through the emitter
The figure shows the schematic network of NPN and PNP Darlington transistor, the Darlington is a transistor having high current gain, which is made by connecting two bipolar transistors back to back, that is by connecting the emitter of one transistor to the second transistor base as like in the figure.
Due to this back-to-back connection, the signal that passes towards the Darlington transistor will amplify two times by both transistors, and this connection also offers higher current gain.
TIP120 transistor package
The Tip120 Darlington transistor had the package of TO-220, it is a bulkier transistor package mainly used for power transistors.
TO-220 package had two portions, the first one is a heat resistant portion made with a mixture of epoxy and plastic material and the second portion is the heat sink portion made with metal for, attaching the heat sink with it.
Marking the case
The marking of this transistor is TIP120 at the case
TIP120 transistor electrical specification description
In this section, we try to explain the electrical specifications of the TIP120 transistor, which is helpful in the replacement process.
The terminal voltage specs of the TIP120 transistor are collector to emitter and collector to base voltage is 60V and emitter to base voltage is 5V, the voltage values show it is a medium power device.
Collector to emitter saturation voltage is 2V to 4V, it is the voltage value needed for switching.
Collector current is 5A, the current value of the transistor shows the load capacity of the device, TIP120 is a transistor having higher capacity.
The power dissipation at the TIP120 transistor is 65W, the device dissipation mainly depends on the transistor package and overall capacity.
Current gain specs
The current gain value of TIP120 is 1000hFE, the DC current value shows that it is capable of amplifier and driver applications.
The small-signal current gain value of the TIP120 transistor is 4hFE, so in small-signal applications, the TIP120 transistor had poor current gain.
The junction temperature of -65 to 150℃, and the TIP120 is a power transistor.
The thermal resistance of the TIP120 transistor case is 1.92℃/W
TIP120 Darlington transistor DATASHEET
If you need the datasheet in pdf please click this link
TIP120 transistor equivalent
The TIP120 transistor had two types of equivalent transistors, one is the Darlington transistors such as TIP101, 2N6388, and TIP121, and the second is normal power transistors such as 2N6530, 2N6532, 2SD1191, 2N6043 and 2N6045.
Both these two transistor types are the equivalent transistors of TIP120, the electrical characteristics of each transistor are mostly identical, but we need to check and verify the before the replacement process.
TIP120 transistor complementary
TIP120 Darlington NPN transistors have complementary devices such as TIP125 and TIP127 PNP Darlington transistors.
TIP120 vs TIP31 vs IRF530
In the table below we try to compare TIP120, TIP31, and TIP122 transistors, the electrical specification comparison is really helpful for circuit making.
|Collector to base voltage (VCB)
|Collector to emitter voltage (VCE)
|Emitter to base voltage (VEB)
|Collector to emitter saturation voltage (VCE (SAT))
|2V to 4V
|2V to 4V
|Collector current (IC)
|Junction temperature (TJ)
|-65 to +150°C
|-65 to +150°C
|-55 to +150°C
|Transition frequency (FT)
|25 to 50hFE
Almost many of the electrical specifications of TIP120, TIP122, and TIP31 transistors are the same.
The DC current gain value of TIP120 and TIP122 transistors is the same and TIP31 is less, this is why both these transistors had amplifier and driver applications.
TIP120 Darlington transistor applications
- General-purpose linear and switching applications
- General-purpose amplifier circuits
- Low-speed switching applications
- Speed controlling of motor
- Inverter circuits
- Power rectifier circuits
TIP120 transistor characteristics
The figure shows the DC current gain characteristics of the TIP120 transistor, the graph is plotted with DC current gain vs collector current.
At the fixed collector to emitter voltage, the gain value increases from a low value to a higher one and decreases at the end with respect to collector current.
The gain value variations will be also reflected at the junction temperature of the device.
The figure shows the collector to emitter saturation voltage characteristics of the TIP120 transistor, the graph is plotted with the collector to emitter saturation vs base current.
The graphical variations are been plotted with different collector current values, the saturation value is almost fixed, and the base current varies.