74HC297 Datasheet, PDF (5/12 Pages) NXP Semiconductors – Digital phase-locked-loop filter

Philips Semiconductors
Digital phase-locked-loop filter
Product specification
74HC/HCT297
Fig.4 Functional diagram.
K-COUNTER (DIGITAL CONTROL) FUNCTION TABLE
D
C
B
A
MODULO (K)
L
L
L
L
L
L
L
H
L
L
H
L
L
L
H
H
L
H
L
L
L
H
L
H
L
H
H
L
L
H
H
H
H
L
L
L
H
L
L
H
H
L
H
L
H
L
H
H
H
H
L
L
H
H
L
H
H
H
H
L
H
H
H
H
inhibited
2³
2⁴
2⁵
2⁶
2⁷
2⁸
2⁹
2¹⁰
2¹¹
2¹²
2¹³
2¹⁴
2¹⁵
2¹⁶
2¹⁷
EXCLUSIVE-OR PHASE DETECTOR FUNCTION
TABLE
φA₁
φB
L
L
L
H
H
L
H
H
XORPD_OUT
L
H
H
L
EDGE-CONTROLLED PHASE DETECTOR TABLE
φA₂
H or L
↓
H or L
↑
φB
↓
H or L
↑
H or L
ECPD_OUT
H
L
no change
no change
Notes
1. H = HIGH voltage level
L = LOW voltage level
↓ = HIGH-to-LOW transition
↑ = LOW-to-HIGH transition
September 1993
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