ADF4207 datasheet(17/20 Pages) AD

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REV. 0

ADF4206/ADF4207/ADF4208

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RF SECTION (RF1)

Programmable RF1 Reference (R) Counter

If control bits (C2, C1) are (1, 0), the data is transferred from

the input shift register to the 14 Bit RF1 R counter. Table V

shows the input shift register data format for the RF1 R counter

and the divide ratios possible.

RF1 Phase Detector Polarity

P9 sets the RF1 Phase Detector Polarity. When the RF1 VCO

characteristics are positive this should be set to “1.” When they

are negative it should be set to “0.” See Table V.

RF1 Charge Pump Three-State

P10 puts the RF1 charge pump into three-state mode when

programmed to a “1.” It should be set to “0” for normal opera-

tion. See Table V.

RF1 Program Modes

Table III and Table V show how to set up the Program Modes

in the ADF420x family.

RF1 Charge Pump Currents

Replaced with a P13 programs the current setting for the RF1

charge pump. See Table V.

Programmable RF1 AB Counter

If control bits (C2, C1) are (1, 1), then the data in the input

counter consists of a 6-bit swallow counter (A counter) and

11-bit programmable counter (B counter). Table VI shows

the input register data format for programming the RF1 AB

counter and the divide ratios possible. See Table VI.

RF1 Prescaler Value

P14 in the RF1 A, B counter latch set the RF1 prescaler value.

See Table VI.

RF1 Power-Down

Setting P16 in the RF1 AB counter high powers down RF1 side.

RF Fastlock

The fastlock feature can improve the lock time of the PLL. It

increases charge pump current to a maximum for a period of

time. Fastlock of the ADF420x family is activated by setting

P13 in the reference counter high and setting the fastlock switch

on using MUXOUT. Switching in an external resistor using

MUXOUT compensates the loop dynamics for the effect of

increasing charge pump current. Setting P13 low removes the

PLL from fastlock mode.

OSC

OUT

MUXOUT

ADF4207

DD2 VDD1VP1

RF1

RF2IN

RF1IN

OSC

CLK

DATA

DECOUPLING CAPACITORS (22 F/10pF) ON VDD, VP OF

THE ADF4207, AND ON VCC OF THE VCOs HAVE BEEN

OMITTED FROM THE DIAGRAM TO AID CLARITY.

VCO190-125T

RF2

100pF

OUT

100pF

30pF

10MHz

18k

1.3nF

13nF

2.7k

620pF

3.3k

100pF

OUT

100pF 18

100pF

LOCK DETECT

30pF

VCO190-1068U

Figure 7. GSM Handset Receiver Local Oscillator Using the ADF4207

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