CD74ACT297

DIGITAL PHASE-LOCKED LOOP

SCHS297D – AUGUST 1998 – REVISED JUNE 2002

6

POST OFFICE BOX 655303

detailed description (continued)

Thus, the simple first-order phase-locked loop with an adjustable K counter is the equivalent of an analog

phase-locked loop with a programmable VCO gain.

D/U

φA2

Divide-by-K

Counter

Divide-by-N

Counter

Mfc

I/D Circuit

I/D OUT

I/D CLK

Carry

Borrow

K CLK

XORPD OUT

φB

fin,

φin

2 Nfc

fout,

φout

φA1

J

K

ECPD

ENCTR

Figure 3. DPLL Using Both Phase Detectors in a Ripple-Cancellation Scheme

–0.5 V to 6 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

±20 mA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

±50 mA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

±50 mA

. . . . . . . . . .

±100 mA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Package thermal impedance,

73

°C/W

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–65

°C to 150°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTES:

1. For up to four outputs per device, add

±25 mA for each additional output.

2. The package thermal impedance is calculated in accordance with JESD 51-7.

recommended operating conditions

MIN

MAX

UNIT

VCC

Supply voltage

4.5

5.5

V

VIH

High-level input voltage

2

V

VIL

Low-level input voltage

0.8

V

VI

Input voltage

0

VCC

V

VO

Output voltage

0

VCC

V

∆t/∆v

Input rise and fall slew rate

10

ns

TA

Operating free-air temperature range

–55

125

°C