6
MB15C101
■FUNCTIONAL DESCRIPTIONSTwo different frequencies can be selected by Div input “H” or “L”.
The divide ratios are calculated using the following equation:
fVCO = {(P × N) + A} × fOSC ÷ R (A < N)
■PHASE DETECTOR TIME CHART Note: • .Phase error detection range: –2π to +2π
• Pulses on Do output signal during locked state are output to prevent dead zone.
• LD output becomes low when phase is tWU or more. LD output becomes high when phase error is tWL or
less and continues to be so for three cycles or more.
•.t
WU and tWL depend on OSCin input frequency.
tWU > 8/fosc (s) (e. g.tWU > 625.0ns, foscin = 12.8 MHz)
tWL < 16/fosc (s) (e. g. tWL < 1250.0ns, foscin = 12.8 MHz)
Symbol Description Div = “H” Div = “L”
fvco Output frequency of external VCO 233.15 MHz 259.20 MHz
fosc Reference oscillation frequency 19.2 MHz 19.2 MHz
N Divide ratio of the main counter 291 33
A Divide ratio of the swallow counter 7 12
PPreset divide ratio of dual modulus
prescaler 16/17 16/17
R Divide ratio of the reference counter 384 (fr = 50 kHz) 40 (fr = 480 kHz)
fr
fp
LD
DO High impedance
tWLtWU