NBC12429 ,3.3V / 5V Programmable PLL Synthesized Clock Generator (25 to 400 MHz)Prepared by: Terry McHenry, FAEJoseph HughesAPPLICATION NOTEIC Design EngineerON SemiconductorINTRO ..
NBC12429AMNR4G , 3.3V/5V Programmable PLL Synthesized Clock Generator
NBC12429FAR2G , 3.3V/5V Programmable PLL Synthesized Clock Generator
NBC12429FN ,3.3V / 5V Programmable PLL Synthesized Clock Generator (25 to 400 MHz)2AND8120/D25 2520 20MC N=815 15MC N=4ON N=810 10 MC N=2MC N=1ON N=4ON N=25 5ON N=10 0100 20 ..
NBC12430 ,3.3V / 5V Programmable PLL Synthesized Clock Generator (50 to 800 MHz)2XTAL2VCCOEFOUTP_LOADFOUTM[0]GNDM[1]VCCM[2]TESTM[3]GNDXTAL2 VCCOE FOUTFP_LOADOUTM[0] GNDM[1] VCCM[2 ..
NBC12430FA ,3.3V / 5V Programmable PLL Synthesized Clock Generator (50 to 800 MHz)3AND8090/DAC Test BoardsAn example of an AC characteristic test board is shown inEach test device i ..
NJM2103L , SYSTEM RESET IC
NJM2106M , ACTIVE BASS EXPANDER
NJM2107 , SINGLE OPERATIONAL AMPLIFIER
NJM2107 , SINGLE OPERATIONAL AMPLIFIER
NJM2110M , MONORAL MIC AMP for VIDEO CAMERA
NJM2110M , MONORAL MIC AMP for VIDEO CAMERA
NBC12429-NBC12429FN
3.3V / 5V Programmable PLL Synthesized Clock Generator (25 to 400 MHz)
AND8120/D
A Comparison of the
NBC12429 and MC12429
Programmable PLL Clock
Synthesizers
Prepared by: Terry McHenry, FAEJoseph Hughes
IC Design Engineer
ON Semiconductor
INTRODUCTIONON Semiconductor, recognizing that companies need to
focus their engineering resources on new products instead of
re-engineering products already in production, has created
direct drop-in replacements for three Motorola clock
synthesizers.
Motorola recently announced their decision to migrate the
MC12429, MC12430, and MC12439 to a new process. This
migration means that existing customers will need to do a
complete evaluation of Motorola’s new parts to insure
compatibility with existing designs.
This paper presents a side-by-side comparison of key
specifications for the ON Semiconductor NBC12429 and
the Motorola MC12429 (at the time this paper was written
the NBC12430 and NBC12439 had not been released;
however, they should also be very similar to their Motorola
counterparts).
Process TechnologyMotorola’s MC12429 uses a process called BIC75, which
is an older BiCMOS process, while Motorola’s new part
uses a completely different SiGe process. The control
section of the EOL’ed MC12429 is CMOS but the PLL
portion, the heart of the chip, is bipolar.
ON Semiconductor decided to create a drop in part using
their highly successful MOSAIC V (M5) process, the same
bipolar process that is used to produce some of the fastest
ECL available, ECLinPS Plus (see www. for
more details on the EP and LVEP families). It was also
decided to create this part as a fully differential design to
decrease noise generation and increase power supply
rejection.
ON Semiconductor could have produced this part in SiGe
as well but an all silicon bipolar approach made duplication
of the existing critical timing much easier to achieve.
At a lower level, process technology is a good way to
compare parts, but the real test comes in the performance
comparison.
Table 1 compares some of the key timing parameters for
the parts. As can be seen, the silicon-based parts are nearly
identical, leading to high confidence of a drop-in solution;
the same cannot be said of Motorola’s SiGe part.
Note that the jitter performance of the ON Semiconductor
part is significantly better than the Motorola parts. Figure 1
shows both the cycle-to-cycle RMS jitter and the
cycle-to-cycle
only is the NBC12429 jitter significantly lower than the
MC12429, but there is also less jitter variation over the VCO
range.
When it comes to PLL performance
specifications only tell part of the story. A great deal of
engineering effort was also expended on the two most
difficult attributes of the Motorola part to duplicate, the
crystal oscillator and the loop dynamics.
The crystal oscillator is very flexible; it will accept low Q,
medium Q, and high Q crystals from 10MHz to 20MHz.
Achieving this took several iterations, but it is important for
a drop-in replacement to be able to operate equally well
from any reasonable crystal. A replacement clock
synthesizer should not have the engineer hunting for a new
crystal as well.
Loop dynamics are characterized by lock time (loop
bandwidth) and overshoot. Table 2 contains laboratory
measurements of the two silicon devices (taken from several
lots and several date codes) showing how closely they
compare. Figures 5 and 6 illustrate graphically that lock time
and overshoot are very similar, with no ringing. It is
important to note that both Table 2 and Figures 5 and 6 depict
a very large frequency step, from 200MHz to 400MHz.
