BF245 transistor

BF245 transistor
BF245 transistor

BF245 specification

  • BF245 FET N-channel depletion field effect transistor device
  • Drain to source voltage (VDS) is +/-30V
  • Drain-to-gate voltage (VDG) is 30V
  • Gate to source Cutoff voltage (VGS (off)) is -0.5V to -8.0V
  • Drain current (ID) is 100mA
  • Gate current (IG) is 10mA
  • Power dissipation (PD) is 350mW
  • Input capacitance (Ciss) is 3pF
  • Output capacitance (Coss) is 9pF
  • Junction temperature (TJ) is between -65 to 150℃
  • Thermal resistance of the ambient is 250℃/W
  • Frequency value is 700MHz
  • VHF/UHF amplifier device
  • General purpose device
  • Symmetrical junction
  • Interchangeability of drain and source connection
  • Frequency upto 700MHz


Pin Number Pin Name Description
1 Drain   The drain terminal is the current inlet of the JFET device
2 Source In the source, terminal current flows out from the JFET 
3 Gate The gate terminal is the trigger for the device


BF245 package

BF245 amplifier device has a TO-92 package, it is a semiconductor device that is made of epoxy/plastic material.

TO-92 is a three-terminal device package which had higher temperature capacity and compactness as the electronic component.

BF245 transistor specification and application description note:

Here in this section, we explain the electrical specifications of the BF245 transistor, this explanation is useful for a better understanding of the device for circuit-level uses.

Voltage specs

The terminal voltage specifications of the BF245 transistor is the drain-to-source +/-30V, the gate-to-source voltage is 0.4 to 7.5V, and gate to source cutoff voltage value is -0.5V and -8.0V.

The voltage specs of the BF245 transistor show that it is a device have low-voltage amplifier applications.

Current specs

The gate current value of the BF245 transistor is 10mA, and the current value of the device indicates the load capacity.

Dissipation specs

Dissipation ability of the BF245 transistor is 350Mw, this mainly depends on the device package.

Junction temperature

The maximum temperature value of the BF245 FET transistor is65 to +150.

Input capacitance

The input capacitance of the BF245 transistor is 3Pf, this value is started from the inner layer of the device.

Thermal resistance

The thermal resistance between the junction and ambient is 250K/W, which depends on the device package.


The frequency value of the BF245 transistor is 700MHz.

Noise figure

The noise figure value of the BF245 transistor is 1.5dB


If you need the datasheet in pdf please click this link


BF245 FET transistors have equivalent transistors such as BF245C, 2N5457, 2SK117, MPF102, NTE457, J113, 2N3819, and 2SK518, each of these transistors has the same set of electrical specifications.

The specifications such as voltage, current, noise figure, and frequency is important for amplifier circuits, so check and verify these specs of all equivalent device before the replacement.

BF245 vs 2SK117

In the table below we compare the electrical specifications of BF245 and 2SK117 FET transistors, this comparison is very useful for a better understanding of the device for circuit applications.

 Drain-to-gate voltage (VDG)30V50V
Gate to source cutoff voltage (VGS(OFF))-0.5 to -8.0V-0.2 to -1.5V
 Gate to source  voltage (V­GS)0.4 to 7.5V-
Gate forward current (IG)10mA       10mA
Power dissipation (PD)350mW300mW
Junction temperature (TJ)-65 to 150°C-55 to 125°C
Thermal resistance250K/W-
Input capacitance (Ciss)3pF13pF
Output capacitance0.9pF-
Noise figure (NF)1.5dB10dB

BF245 characteristics curves

output characteristics of the BF245 FET transistor
output characteristics of the BF245 FET transistor

The figure shows the output characteristics of the BF245 FET transistor, the graph plots with drain current vs drain to source voltage.

At the different gate-to-source voltage values, the drain current increases from a lower value and become constant with respect to voltage.

BF245 transistor applications

  • VHF amplifier circuit
  • UHF amplifier circuit
  • RF oscillator circuit
  • Preamp circuit
  • Low-level signal amplifier circuit
  • Sensor circuit
  • Detector circuit
  • Low-frequency amplifier
  • High-frequency amplifier
  • DC amplifier circuit

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