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PMB2349

Wireless Components Optimized RF/IF Dual PLL Frequency Synthesizer

Infineon Technologies 

Confidential

PMB 2349

preliminary

Functional Description

3.4.3 Standby Condition (power down)

Each PLL of the PMB 2349 has two programmable standby modes to reduce

the current consumption (standby 1, standby 2).

Standby 1: The corresponding PLL is switched off, the current consumption

is reduced below 1 µA.

Standby 2: The corresponding counters, the charge pump and the outputs

are switched off. Only the preamplifier of RI-input stays active.

(See standby table)

3.4.4 Divide ratio programming

The frequency of an external VCO controlled by the PMB 2347 is given below:

fVCO

=

[(P ⋅ N) + A] ⋅ -f-R-R---I

=

M----

R

⋅

fRI

with A ≤ N .

fVCO:

fRI:

N:

A:

P:

R:

M=P*N+A:

frequency of the external VCO

reference frequency

divide ratio of the N-counter

divide ratio of the A-swallow counter

divide ratio of the prescaler

divide ratio of the R-counter

total divide ratio

Note:

for continous frequency steps following condition is necessary

[P ⋅ N + A] ≥ P ⋅ (P – 1)

3.4.5 Prescaler Divide Ratio

For the highest input frequencies of the prescalers the larger divide ratio is nec-

essary:

RF-PLL: 64/65 for frequencies greater 1500 MHz

IF-PLL:

16/17 for frequencies greater 375 MHz

Wireless Components

3 - 10

Specification, May 2000

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