This Product Selection Guide contains information to help select products in the Attenuators category on DigiKey.com
Attenuators are designed to reduce the power of a signal with minimal effect on its waveform. The attenuation value ranges from 0 dB to 69 dB with a frequency range from 0 to 86 GHz.
SelectionCharacteristics
Specifications to determine which attenuators may be right for your application.
Attenuation Value: Characterizes the amount by which a device reduces the strength of an applied signal. May be a fixed value or value range, for devices that provide an adjustable attenuation function.
Attenuation values are usually going to be one the most important traits. You may find that this value can vary and while it might look like one of the variable options (listed with a range) might be the way to go just remember that a variable option will have some more complex requirements which could include additonal parts needed to support it’s functionality.
Frequency Range: Some attenuators are designed and specified for relatively broadband use such as from 1 to 4 GHz, while others target narrowband situations such as the nominal 2.4 GHz ISM band. Although wider bandwidth may seem to be a benefit, it is more difficult to design and costly to achieve performance over a wider band. A comparable situation exists for variable attenuators. A wide-range unit which functions over a range of 60 or more dB is more costly than one which must do so over a more limited range of 30 dB.
The two parameters of frequency range and attenuation combine for other critical specifications: attenuation deviation or flatness across the frequency range, and across operating temperature. Flatness is typically on the order of 0.25 dB or 0.5 dB and is generally harder to maintain at higher frequencies.
If the attenuator is a fixed-value unit, the flatness needs to be specified only at that single dB value. However, for variable attenuators, the flatness may vary with the amount of attenuation, so its variations must be specified at different attenuation values, such as every 5 or 10 dB. Finally, as with nearly all passive and active components, performance must be specified at nominal temperature (25⁰C) as well as the device’s rated low and high temperatures; some vendors offer temperature coefficient data as well.
Power (Watts): Power-handling capacity for attenuators ranges from milliwatts to thousands of watts. The power rating is one factor which determines the possible package, which can be a tiny surface-mount technology (SMT) device to larger coaxial and even waveguide packages, as power levels go to upper levels. Regardless of package type, most vendors specify power ratings for both continuous-wave (CW) operation as well as peak value for pulsed operation. Depending on the duty cycle of the pulse rating used, the ratio between CW- and peak-power ratings can be a factor of ×10, ×100, or more.
Impedance: Of course, as with all RF components, the impedance of the attenuator should match the circuit. Most attenuators are designed for 50 Ω operation; some specialized ones are available for other values such as 75 Ω. If the circuit does not have a matching value, an impedance-matching circuit may be needed.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the suppliers device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
ProductExamples
| DigiKey Part Number | PAT05S8TR-ND | |
| Manufacturer | Susumu | |
| Manufacturer Product Number | PAT0510S-C-8DB-T10 | |
| Description | RF ATTENUATOR 8DB 50OHM 0402 | |
| Datasheet | Click Here |
| DigiKey Part Number | 116-M3933/25-70N-ND | |
| Manufacturer | Cinch Connectivity Solutions Midwest Microwave | |
| Manufacturer Product Number | M3933/25-70N | |
| Description | RF Attenuators 6dB 0 Hz ~ 18 GHz SMA In-Line Module | |
| Datasheet | Click Here |
| DigiKey Part Number | 1127-1641-ND | |
| Manufacturer | Analog Devices Inc. | |
| Manufacturer Product Number | HMC-C025 | |
| Description | RF Attenuators 0.5dB ~ 31.5dB 0 Hz ~ 13 GHz 50 Ohms SMA In-Line Module | |
| Datasheet | Click Here |
Schematic Symbols
Schematic symbol courtesy of Scheme-it. Please see their website for more information and symbols.
MediaLinks
Videos
MACOM’s Voltage Variable Attenuator | MAAV-011013
ADRF5720 and ADRF5024
Articles
RF Attenuators: For When You Have Too Much of a Good Thing
Understand the Fundamentals of Coaxial Adapters to Make Better Use of These…
Product Training Modules
ATS Series of High-Frequency Attenuators
AT-100V Attenuator Series
Chip RF Attenuator - Walsin
If you have any questions on the specifications for selecting an Attenuator, please reply using the button below. If you have questions on a specific Attenuator, please post those questions in the Wireless and IoT category.