3

ClockWorks™

SY89425

Micrel

INPUTS

RFCKB [Reference Clock B] TTL

Reference clock in for PLL B. (38.88, 51.84 or 77.76MHz).

SEL39B [38.88MHz Select B] TTL

Logic HIGH on this pin denotes a 38.88MHz input reference

clock for PLL B. Tie to logic LOW if input is not 38.88MHz.

SEL78B [77.76MHz Select B] TTL

Logic HIGH on this pin denotes a 77.76MHz input reference

clock for PLL A. Tie to logic LOW if input is not 77.76MHz.

RSTB [Reset B] TTL

Tie to logic LOW for normal operation; logic HIGH forces reset

of internal Phase Detector & feedback dividers on PLL B.

FLTRBP, FLTRBN (Loop Filter B, Pos & Neg) Analog.

Connect a series RC loop filter between these pins. The

suggested loop filter is 0.1

µF and 500 ohms, as shown in the

typical application on page 3-9.

RSTA (Reset A) TTL

Tie to logic LOW for normal operation; logic HIGH forces reset

of internal Phase Detector & feedback dividers on PLL A.

SEL78A [77.76MHz Select A] TTL

Logic HIGH on this pin denotes a 77.76MHz input reference

clock for PLL A. Tie to logic LOW if input is not 77.76MHz.

SEL39A [38.88MHz Select A] TTL

Logic HIGH on this pin denotes a 38.88MHz input reference

clock for PLL A. Tie to logic LOW if input is not 38.88MHz.

PIN DESCRIPTION

REFCKA [Reference Clock A] TTL

Reference clock in for PLL A.

FLTRAP, FLTRAN (Loop Filter A, Pos & Neg) Analog.

Connect a series RC loop filter between these pins. The

suggested loop filter is 0.1

µF and 500 ohms, as shown in the

typical application on page 5-527.

OUTPUTS

CK622BP, CK622BN (Clock Out B) Differential PECL

622.08MHz output clock from PLL B.

CK622AP, CK622AN (Clock Out A)

Differential PECL

622.08MHz output clock from PLL A.

POWER & GROUND

+5V for PLL A.

+5V for PLL B.

+5V for PLL A PECL outputs.

+5V for PLL B PECL outputs.

GND

Ground (0 volts)

REFERENCE FREQUENCY SELECTION

SEL39

SEL78

fRFCK

0

0

51.84

0

1

77.76

1

0

38.88

1

1

77.76

Symbol

Parameter

Rating

Unit

Power Supply

0 to +7

V

Input Voltage

V

Output Current

–Continuous

50

mA

–Surge

100

Operatimg Temperature Range

0 to +85

°C

Storage Temperature Range

–65 to +150

°C

NOTE:

1. Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. This is a stress rating only and functional operation is not

implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to ABSOLUTE MAXIMUM RATING conditions

for extended periods may affect device reliability.