I bought a pair of AD831 pre-assembled modules from China, $10 each – not bad considering the price of the individual AD831 chip, the board comes ready to use “plug and play” with all ports terminated in to 50 ohms with SMA connectors – neat.
Testing the mixer saw excellent results and the added bonus of some gain, around 10dB for a 9V supply – I tried them at 12V but got too warm for my liking, even at 9V they still got relatively hot to the touch.
One thing I will have to remember is local oscillator drive – these active mixers will perform with as little as -10dB drive!
Here is the spec taken from the supplier on aliexpress.com
AD831 is a low distortion, wide dynamic range, single-chip mixers, such as the frequency for lower HF and VHF receiver RF-IF, DMR base station in a second mixer, DC – baseband conversion, quadrature modulation and demodulation, and ultrasound imaging of the Doppler shift detection applications.
AD831 provides +24 dBm third-order intercept point, -10 dBm LO power consumption can be achieved without high power LO drive, there was no corresponding mask and isolate problems, as compared with the passive mixer can be improved system performance and reduce system cost.
The mixer designed for single power supply, RF, IF, and LO port has a DC blocking capacitors, easy to use. RF and LO input operating frequency up to 500MHz. IF output is single-ended voltage output. With a 250 MHz output bandwidth. A single resistor connected between OUT and FB pin is used to set the gain. The amplifier has a low dc offset feature, which can be used in DC – baseband conversion and quadrature amplitude demodulation DC-coupled applications.
When the mixer output amplifier and optimum source impedance, the mixer’s SSB noise figure at 70 MHz when 10.3 dB. Passive mixer different, AD831 insertion loss not exist without an external diplexer does not need to be a passive termination.
- RF input: 0.1-500MHz
- RF input: + 10dBm (1dB compression point)
- LO input: 0.1-500MHz
- LO input: -10dBm
- IF output: 0.1-200MHz (It is actually DC-200MHz)
- Supply voltage: 9–11V Single Ended