AD9552 데이터 시트보기 (PDF) - Analog Devices

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AD9552

Oscillator Frequency Upconverter

Analog Devices 

Data Sheet

AD9552

THEORY OF OPERATION

REFA

XTAL

XTAL

DETECTOR

2×

TUNING

CONTROL

LOCKED

FILTER

LOCK

DETECT

AD9552

PFD

CHARGE

PUMP

3350MHz TO

4050MHz

VCO

4 TO 11 1 TO 63

P0

P1

N = 4N1 + N0

N1

4 OR 5

2

OUT2

2

OUT1

SERIAL

PORT

A2:0

Y5:0

3

REGISTER BANK

3

PRECONFIGURED

6

DIVIDER VALUES

Σ-Δ

N

MODULATOR

MOD,

FRAC

N, MOD, FRAC, P0, P1

P0, P1

Figure 19. Detailed Block Diagram

PRESET FREQUENCY RATIOS

The frequency selection pins (A[2:0] and Y[5:0]) allow the user

to hardwire the device for preset input and output divider values

based on the pin logic states (see Figure 19). The pins decode

ground or open connections as Logic 0 or Logic 1, respectively.

Use the serial I/O port to change the divider values from the

preset values provided by the A[2:0] and Y[5:0] pins.

The A[2:0] pins select one of eight input reference frequencies

(see Table 9). The user supplies the input reference frequency by

connecting a single-ended clock signal to the REF pin or a crystal

resonator across the XTAL pins. If the A[2:0] pins select 10 MHz,

12 MHz, 12.8 MHz, or 16 MHz, the input frequency to the AD9552

doubles internally. Alternatively, if Register 0x1D[2] is set to 1,

the input frequency doubles.

Table 9. Input Reference Frequency Selection Pins

A2

A1

A0

Reference Frequency (MHz)

0

0

0

10.00

0

0

1

12.00

0

1

0

12.80

0

1

1

16.00

1

0

0

19.20

1

0

1

19.44

1

1

0

20.00

1

1

1

26.00

The Y[5:0] pins select the appropriate feedback and output dividers

to synthesize the output frequencies (see Table 10). The output

frequencies provided in Table 10 are exact; that is, the number of

decimal places displayed is sufficient to maintain full precision.

Where a decimal representation is not practical, a fractional

multiplier is used.

The VCO and output frequency shift in frequency by a ratio of the

reference frequency used vs. the frequency specified in Table 9.

Note that the VCO frequency must stay within the minimum and

maximum range specified in Table 1. Typically, the selection of

the VCO frequency band, as well as the gain adjustment, by the

external pin strap occurs as part of the device’s automatic VCO

calibration process, which initiates at power up (or reset). If the

user changes the VCO frequency band via the SPI interface,

however, a forced VCO calibration should be initiated by first

enabling SPI control of the VCO calibration (Register 0x0E[2] = 1)

and then writing a 1 to the calibrate VCO bit (Register 0x0E[7]).

Rev. E | Page 13 of 32

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