ADF4356BCPZ datasheet(24/35 Pages) AD

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ADF4356

Data Sheet

Rev. 0 | Page 24 of 35

Charge Pump Bleed Current

BL8 to BL1 (Bits[DB20:DB13]) control the level of the bleed

current added to the charge pump output. This current

optimizes the phase noise and spurious levels from the device.

Calculate the optimal bleed setting using the following rule.

Bleed Value = floor(24 × (fPFD/61.44 MHz) × (ICP/0.9 mA))

If fPFD > 100 MHz, disable bleed current using DB29.

where:

Bleed Value is the value programmed to Bits[DB20:DB13].

floor() is a function to round down to the nearest integer value.

fPFD is the PFD frequency.

ICP is the value of charge pump current setting, Bits[DB13:DB10] of

Mute Till Lock Detect

When D8 (Bit DB11) is set to 1, the supply current to the RF

output stage is shut down until the device achieves lock, as

determined by the digital lock detect circuitry.

RF Output B Enable

D6 (Bit DB9) enables or disables RF Output B (RFOUTB+/RFOUTB−).

If DB10 is set to 0, RF Output B is enabled. If DB10 is set to 1,

the RF Output B is disabled.

RF Output B Power

D5 and D4 (Bits[DB8:DB7]) set the value of the RF Output B

(RFOUTB+/RFOUTB−) power level (see Figure 34).

RF Output A Enable

D3 (Bit DB6) enables or disables RF Output A (RFOUTA+/RFOUTA−).

If DB3 is set to 0, RF Output A is disabled. If DB6 is set to 1, RF

Output A is enabled.

RF Output A Power

D2 and D1 (Bits[DB5:DB4]) set the value of the RF Output A

(RFOUTA+/RFOUTA−) power level (see Figure 34).

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