XRK69774 Datasheet, PDF (1/11 Pages) Exar Corporation – 1:14 LVCMOS PLL CLOCK GENERATOR

PRELIMINARY
XRK69774
1:14 LVCMOS PLL CLOCK GENERATOR
APRIL 2006
REV. P1.0.1
GENERAL DESCRIPTION
The XRK69774 is a PLL based LVCMOS Clock Generator
targeted for high performance and low skew clock distribu-
tion applications. The XRK69774 can select between one
of two reference inputs and provides 15 LVCMOS outputs -
14 outputs (2 banks of 5 and 1 bank of 4) for clock distribu-
tion and 1 for feedback.
The XRK69774 has two LVCMOS inputs to support clock
redundancy. Switching the internal reference clock is con-
trolled by the control input, CLK_SEL.
The XRK69774 uses PLL technology to frequency lock its
outputs to the input reference clock. The divider in the feed-
back path will determine the frequency of the VCO. Each of
the separate output banks can individually divide down the
VCO output frequency. This allows the XRK69774 to gen-
erate a multitude of different bank frequency ratios and out-
put-to-input frequency ratios.
The outputs of the XRK69774 can be immobilized, in the
low state, by use of the stop clock feature. Global output
disabling and reset can be achieved with the control input
MR/OE.
The XRK69774 has an output frequency range of 8.33MHz
FIGURE 1. BLOCK DIAGRAM OF THE XRK69774
to125MHz and an input frequency range of 4.16MHz to
62.5MHz.
FEATURES
• Fully Integrated PLL
• 15 LVCMOS outputs
■ 2 banks with 5 outputs and 1 with 4 outputs
each
■ 1 dedicated feedback for frequency control
■ Output Frequency of each Bank can be
individually controlled
• VCO Range 200MHz to 500MHz
• Output freq. range: 8.33MHz to 125MHz
• Max Output Skew of 175ps
• Max Cycle-to-cycle jitter: 90ps
• LVCMOS inputs for reference clock source
APPLICATIONS
• System Clock generator
• Zero Delay Buffer
VDD
CLK0
CLK1
CLK_SEL
FB_IN
PLL_EN
VCO_SEL
FSEL_A
FSEL_B
FSEL_C
FSEL_FB[1:0]
0
1
VDD
0
Ref
VCO ₁
PLL
200-500MHz
FB
÷2
0
÷4
1
2
VDD
__________
STOP_CLK
VDD
___
MR/OE
POR
Divider Select
÷2, ÷4
÷2, ÷4
÷4, ÷6
÷4, ÷6, ÷8, ÷12
STOP
CLK
STOP
CLK
STOP
CLK
QA0
QA1
QA2
QA3
QA4
QB0
QB1
QB2
QB3
QB4
QC0
QC1
QC2
QC3
QFB
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com