ADF4602 datasheet(30/36 Pages) AD

30 / 36 page

ADF4602

Rev. 0 | Page 30 of 36

Nonvolatile Memory (NVM) Initialization

The ADF4602 has on-chip non-volatile memory (NVM) that

contains chip factory calibration coefficients. A soft reset of the

device transfers the contents of NVM to internal registers; however,

this has been found to be unreliable if performed at temperatures

below 0°C. The software work-around outlined in Step 2 to Step 5

of Table 14 ensures that the NVM data is transferred reliably

under all operating conditions. It involves setting the VSUP2

on-chip regulator to 3.1 V, manually transferring the data by

setting the nvmld bit in Register 31, and then resetting the

VSUP2 regulator to 2.8 V. Device programming can then

continue as normal.

Programming Transmit and Receive frequencies

After initialization, the transmit/receive synthesizer frequencies

may need to be changed. To change the transmit frequency, write

the new frequency word to Register 26. When a new transmit

frequency is programmed, the transmit output power is auto-

matically turned off to prevent any unwanted transmissions as

the PLL locks. The user should wait 200 μs (time taken for PLL

to lock), and then set the output power to the desired value by

writing to Register 28.

If the user disables the transmit synthesizer, the transmit output

power must be turned off before reenabling the transmit

synthesizer. This is achieved by two means: setting Bit D5 in

minimum.

After reenabling the synthesizer, and then locking the synthesizer

to a frequency by programming the frequency word in Register 26,

the user can reenable the output power.

To change the receive frequency, simply program the new

frequency in Register 10, and wait 200 μs before using the

device as a transceiver. The receive gain is set at any time

(apart from during the 200 μs PLL locking transient).

ADF4602 Datasheet(PDF) 30 Page - Analog Devices