[Shishuo Knowledge] What are the advantages of differential circuits in RF signal chain applications?
When it comes to communication systems, differential circuits always provide better performance than single-ended circuits - they have higher linearity, immunity to common-mode interference signals, etc. Today we will talk about the 4 major advantages of differential circuits in RF signal chain applications.
Differential circuits can be used to achieve
Higher signal amplitude than utilizing single-ended circuits
A differential signal provides twice the amplitude of a single-ended signal at the same supply voltage. It also provides better linearity and SNR performance.
Figure 1. Differential Output Amplitude
Differential Circuitry to External EMI and Nearby Signals
The crosstalk has good immunity
This is because the desired signal voltage received is doubled and the effects of noise on closely coupled traces are theoretically the same and they cancel each other out.
EMI generated by differential signals also tends to be lower
This is because changes in signal level (dV/dt or dI/dt) create opposing magnetic fields, which again cancel each other out.
Differential signaling suppresses even-order harmonics
The following shows an example of continuous wave (CW) passing through a gain block.
When using a single-ended amplifier , as shown in Figure 2, the output can be expressed as Equation 1 and Equation 2.
Figure 2. Single-ended amplifier
When using a differential amplifier, the input and output are shown in Figure 3 and expressed as Equation 3, Equation 4, Equation 5, and Equation 6.
Figure 3. Differential Amplifier
Ideally, the output does not have any even-order harmonics, making differential circuits a better choice for communication systems.
Original text reproduced from Analog Devices
Follow Shijian video account for more information
About ShijianThe leading authorized component agent in the Asia-Pacific region
Excelpoint is a complete solution provider, providing high-quality components and engineering design to Asian electronics manufacturers, including original equipment manufacturers (OEMs), original design manufacturers (ODMs) and electronic manufacturing service providers (EMS). and supply chain management services. It has been listed among the world's leading distributors many times by authoritative magazines and industry organizations.
Shijian has a history of more than 35 years, and its business has expanded to 49 cities and regions in the Asia-Pacific region. It currently has more than ten branches and offices in China. With a professional R&D team, top-notch on-site application support and rich market experience, Shijian enjoys a leading position in the industry in China.
京公网安备 11010802033920号