Datasheet

ADF4108 Data Sheet
Rev. E | Page 4 of 20
Parameter B Version
1
B Chips
2
(Typ) Unit Test Conditions/Comments
NOISE CHARACTERISTICS
Normalized Phase Noise Floor
(PN
SYNTH
)
9
−223 −223 dBc/Hz typ PLL loop B/W = 500 kHz, measured at 100 kHz offset
Normalized 1/f Noise (PN
1_f
)
10
−122 −122 dBc/Hz typ 10 kHz offset; normalized to 1 GHz
Phase Noise Performance
11
@ VCO output
7900 MHz Output
12
−81 −81 dBc/Hz typ @ 1 kHz offset and 1 MHz PFD frequency
Spurious Signals
7900 MHz Output
12
−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
AV
DD
= DV
DD
= 3.3 V.
5
AC coupling ensures AV
DD
/2 bias.
6
Guaranteed by design. Sample tested to ensure compliance.
7
T
A
= 25°C; AV
DD
= DV
DD
= 3.3 V; P = 32; RF
IN
= 8 GHz, f
PFD
= 200 kHz, REF
IN
= 10 MHz.
8
T
A
= 25°C; AV
DD
= DV
DD
= 3.3 V; R = 16,383; A = 63; B = 891; P = 32; RF
IN
= 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 F
PFD
. PN
SYNTH
= PN
TOT
− 10 log F
PFD
− 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, f
RF
,
and at a frequency offset, f, is given by PN = PN
1_f
+ 10 log(10 kHz/f) + 20 log(f
RF
/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 REF
IN
for the
synthesizer (f
REFOUT
= 10 MHz @ 0 dBm).
12
f
REFIN
= 10 MHz; f
PFD
= 1 MHz; f
RF
= 7900 MHz; N = 7900; loop B/W = 30 kHz, VCO = ZComm CRO8000Z.