Fujitsu MB15F74UL Phase Comparator Output Waveform, FC bit = High, FC bit = Low, LD Output Logic

MB15F74UL

■PHASE COMPARATOR OUTPUT WAVEFORM

frIF/RF

fpIF/RF

tWU tWL

LD

(FC bit = High)

DoIF/RF

Z

(FC bit = Low)

DoIF/RF

Z

H

L

L

H

• LD Output Logic

IF-PLL section	RF-PLL section	LD output
Locking state/Power saving state	Locking state/Power saving state	H
Locking state/Power saving state	Unlocking state	L
Unlocking state	Locking state/Power saving state	L
Unlocking state	Unlocking state	L

Notes : • Phase error detection range = −2π to +2π

•Pulses on DoIF/RF signals during locking state are output to prevent dead zone.

•LD output becomes low when phase error 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.

•tWU and tWL depend on OSCIN input frequency as follows.

tWU ≥ 2/fosc : e.g. tWU ≥ 156.3 ns when fosc = 12.8 MHz

tWU ≤ 4/fosc : e.g. tWL ≤ 312.5 ns when fosc = 12.8 MHz

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