Question
Question about AD7740 master clock frequencyVDD is 5V, REFIN is 5V, the crystal's frequency is 100kHz, BUF is connected to GND.
Below is the test resultVin(V) 0 1.5 1.8 2 2.3 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 5Output Frequency(kHz) 9.9 34 38 42 46 50 48.5 46.8 45.2 43.6 42 40 38 37 35 34 32 12When the input voltage is higher than 2.5V, the output frequency reduced.Is this normal?
Answer
Please change the master clock to 1 MHz.The part has been evaluated with a 1 MHz clock only. It operates with a 32 kHz clock also but external circuitry is needed to make it work.The part was not been specified with a 100 kHz clock.Feedback: NO