ADF4108

Data Sheet

Rev. E | Page 4 of 20

Parameter

B Version1

B Chips2

(Typ)

Unit

Test Conditions/Comments

NOISE CHARACTERISTICS

Normalized Phase Noise Floor

(PNSYNTH)9

−223

−223

dBc/Hz typ

PLL loop B/W = 500 kHz, measured at 100 kHz offset

Normalized 1/f Noise (PN1_f)10

−122

−122

dBc/Hz typ

10 kHz offset; normalized to 1 GHz

Phase Noise Performance11

@ VCO output

7900 MHz Output12

−81

−81

dBc/Hz typ

@ 1 kHz offset and 1 MHz PFD frequency

Spurious Signals

7900 MHz Output12

−82

−82

dBc typ

@ 1 MHz offset and 1 MHz PFD frequency

1

Operating temperature range (B version) is −40°C to +85°C.

2

The B chip specifications are given as typical values.

3

This is the maximum operating frequency of the CMOS counters. The prescaler value should be chosen to ensure that the RF input is divided down to a frequency that

is less than this value.

4

AVDD = DVDD = 3.3 V.

5

AC coupling ensures AVDD/2 bias.

6

Guaranteed by design. Sample tested to ensure compliance.

7

TA = 25°C; AVDD = DVDD = 3.3 V; P = 32; RFIN = 8 GHz, fPFD = 200 kHz, REFIN = 10 MHz.

8

TA = 25°C; AVDD = DVDD = 3.3 V; R = 16,383; A = 63; B = 891; P = 32; RFIN = 7.0 GHz.

9

The synthesizer phase noise floor is estimated by measuring the in-band phase noise at the output of the VCO and subtracting 20 log N (where N is the N divider

value) and 10 log FPFD. PNSYNTH = PNTOT − 10 log FPFD − 20 log N.

10

The PLL phase noise is composed of 1/f (flicker) noise plus the normalized PLL noise floor. The formula for calculating the 1/f noise contribution at an RF frequency, fRF,

and at a frequency offset, f, is given by PN = PN1_f + 10 log(10 kHz/f) + 20 log(fRF/1 GHz). All phase noise measurements were performed with the EV-ADF4108EBZ1 and

the Agilent E5500 phase noise system. Both the normalized phase noise floor and flicker noise are modeled in ADIsimPLL.

11

The phase noise is measured with the EV-ADF4108EB1Z evaluation board, with the ZComm CRO8000Z VCO. The spectrum analyzer provides the REFIN for the

synthesizer (fREFOUT = 10 MHz @ 0 dBm).

12

fREFIN = 10 MHz; fPFD = 1 MHz; fRF = 7900 MHz; N = 7900; loop B/W = 30 kHz, VCO = ZComm CRO8000Z.