HMC703LP4E Datasheet, PDF (17/58 Pages) Hittite Microwave Corporation – 8 GHZ FRACTIONAL SYNTHESIZER

v02.0813
HMC703LP4E
8 GHz fractional synthesizer
6 - 17
-20
-40
-60
-80
-100
-120
-140
-160
-180
100
VCO at 1 kHz
PLL at 1 kHz
PLL Floor
VCO at 1 MHz
1000
10⁴
10⁵
10⁶
10⁷
10⁸
FREQUENCY OFFSET (Hz)
Figure 28. Figure of Merit Example
It should be noted that actual phase noise near the corner frequency of the loop bandwidth is affected by loop parame-
ters and one should use a more complete design tool such as Hittite PLL Design for better esti­mates of the phase noise
performance. Noise models for each of the components in Hittite PLL Design can be derived from the FOM equations
or can be provided by Hittite applications engineering.
Spurious Performance
Integer Operation
The VCO always operates at an integer multiple of the PD frequency in an integer synthesizer. In general, spurious
signals originating from an integer synthesizer can only occur at multiples of the PD frequency. These unwanted outputs
are often simply referred to as reference sidebands.
Spurs unrelated to the reference frequency must originate from outside sources. External spurious sources can
modulate the VCO indirectly through power supplies, ground, or output ports, or bypass the loop filter due to poor
isolation of the filter. It can also simply add to the output of the synthesizer.
The HMC703LP4E has been designed and tested for ultra-low spurious performance. Reference spuri­ous levels are
typically below -100 dBc with a well designed board layout. A regulator with low noise and high power supply rejection,
such as the HMC860LP3E, is recommended to minimize external spurious sources.
Reference spurious levels of below -100 dBc require superb board isolation of power supplies, isolation of the VCO
from the digital switching of the synthesizer and isolation of the VCO load from the synthesizer. Typical board layout,
regulator design, demo boards and application information are available for very low spurious operation. Operation
with lower levels of isolation in the application circuit board, from those rec­ommended by Hittite, can result in higher
spurious levels.
Of course, if the application environment contains other interfering frequencies unrelated to the PD fre­quency, and if
the application isolation from the board layout and regulation are insufficient, then the unwanted interfering frequencies
will mix with the desired synthesizer output and cause additional spurs. The level of these spurs is dependant upon
isolation and supply regulation or rejection (PSRR).
F^Irrliniecgo^fseohpr_ntrsomsp_enoasftir_isibtoi_hic^ngilrirtde_yafunpi,^rstnaed_airdstsihee_sbesuyl^dmti_hiv_mebae_dtypmlbr_iAcyay_anyAta9ioa_rlnoen7agsn_luoo8dlDrgt-^eofDr₂^vt_toheio_m5^ceveri_0cwisp_tesi-ssil_use3afsobeuc3_r.neie4_dtSliseep3^vuro_eescader_inf,d_iyc•^tnoae_optriabr_oftens_oe9srn:^a_7tascnH_ou8^cyrbui_j-ipernt2^aacft_rttti^e_5ient_tnoe_g0^atecnr_-mhdiM_g3aehnrn3tei_gstc^lsei₇^aor_{obwf3oflAiept}w_{hn.faoaatHuel}a_otoxngv^wntsoe_{Deotviecr•}^evC_eori,.ctheo_NnesOoor_r. prod^FOPre^ohna^r_roet_npiO_To_erei:nn^cc7e,-_h8,ln2_1inod-3leEe_o2lgil_9via_yz^e-_t4a^rWy7_wb^,a0ye^a_w0,nt_•Pwh^d.OO_.^tDh^or.d_irBeptitov_rli^axet_ocen9,^e_.l1iCc_n0oeo6rh^d,_mae^eNtl^rwom^s:rwws^Awofⁿo_o.aadr^lnd^o,agM,_loM_ADge.0A_cv2oic0m0^e61^s2,8_-9I2ⁿ¹4_0c.6,
Trademarks and registered trademarks are the property of their_Ares_pp_pec_lt_iiv_ce_aow_tin_oer_ns. _{Support: [e-mail] m}Support: Phone: 1-800-ANALOG-D