Left Border Content - RF Cafe
 About RF Cafe Copyright: 1996 - 2024Webmaster:    Kirt Blattenberger,     BSEE - KB3UON RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived... All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged. My Hobby Website: AirplanesAndRockets.com
Header Region - RF Cafe
Sub-Header - RF Cafe

# Opamp Noise Figure

These equations calculate the noise figure of an opamp using parameters provided by vendors at the operating frequency and gain configurations. Be sure to note units both for the input parameters and for the equations, or you will end up with really bad results. I originally got these formulas from an engineering desk reference, but a source accessible by everyone is "Noise Analysis for High-Speed Op Amps," by Texas Instruments (see page 9).

Approximation Formula

VNOISE = Noise voltage density, i.e.  nV/sqrt(Hz)
INOISE = Noise current density, i.e.  pA/sqrt(Hz)
RS = Source resistance, i.e. 50 Ω
k = Boltzmann's Constant = 1.380 662 x 10-23 J/K
T = Ambient temperature in Kelvin

Complete Non-Inverting Opamp Noise Figure Formula (for RS = RT)

Complete Inverting Opamp Noise Figure Formula (for RS = RT)

ENI = Input noise voltage

IBN = Non-inverting input noise current

IBI = Inverting noise current

RS = Source resistor

RT = Termination resistor

RF = Feedback resistor

RG = Gain setting resistor

 Related Pages on RF Cafe - Opamp Noise Figure - Operational Amplifiers (Opamps) - Amplifier Vendors - RF / Operational / Log Video - Amplifier Vendors - Tubes, Vacuum, Klystron, TWT - Amplifier Vendors - Discretes - RF & Analog Amplifier Vendors - Packaged & MMIC - NEETS - Introduction to Amplifiers - Power Amplifier Linearization Using Diode On Voltage - GSM Handset Power Amplifier Control Loop Design
Footer - RF Cafe
Right Border Content - RF Cafe
 Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created. These Are Available for Free