General Description

Transistor is an electronic device used for amplification or switching of electrical signals. NPN transistor is a type of Bipolar Junction Transistor (BJT), which is a current controlled device. Term wideband transistor is used for the transistor which can operate at high transition frequencies. 

Utsource BFG591 is a NPN 7 GHz wideband transistor. Device is manufactured using silicon planar epitaxial technique. Effect of parasitic capacitance and inductance become significant which degrades the performance of the system if not accounted for in the design. This device offers high noise figures and stability.

Features of BFG591

  • High power gain
  • Low noise figure
  • High transition frequency
  • Gold metallization ensures excellent reliability

Replacement Part

BTD2195L3

Pictorial View

Pictorial view of the transistor is shown in figure below, it is available in SOT223 package

Pin Description

Pin description and pin diagram of the BFG591 is shown below

Pin Number 

Pin Name

Description

1

E

Emitter 

2

B

Base 

3

E

Emitter 

4

C

Collector 

IC Electrical Characteristics/ Specifications/datasheet

Some Electrical characteristic of the device are given below

Parameter 

Description 

Value

VCBO

Collector to base voltage with emitter open

120 V

VCEO

Collector to emitter voltage with base open

15 V

IC

Collector current DC

200 mA

PTOT

Total power dissipation

2 W

hFE

DC current gain

60-250

Cre

Feedback capacitance

0.7 pF

fT

Transition frequency

7G Hz

GUM

Maximum unilateral power

13 dB

TJ

Junction temperature

0 To 150 C

TSTG

Storage temperature

-65 to 150 C

Working Principle

BFG591 is a NPN transistor which means it has P type Base and N type Collector and Emitter. Transistor can be biased in one of its three regions of operation which will determine whether the device will work as a switch or as an amplifier. For a transistor to function as a switch it has to be biased in the saturation and cutoff region of its characteristics curve which in turn will represent ON and OFF state of the switch. In order to use a transistor as an amplifier it has to be biased in the active region of its characteristic curve.

Applications and Price

BFG591 can be used in following applications

  • GHz range applications
  • MATV amplifier
  • CATV amplifier
  • RF communication equipment.
  • BFG591 price could be found from different places

Broadband Amplifier

Circuit diagram of broadband amplifier using BFG591 is shown below. Resistor R1 and R2 determines the gain of the circuit while resistor R3 determines the impedance of the circuit.

500mW Linear Amplifier

Circuit diagram of linear amplifier using BFG591 is shown below, two transistors are used to produce output power of 500 mW.