8705BY

www.icst.com/products/hiperclocks.html

REV. G JUNE 16, 2004

1

Integrated

Circuit

Systems, Inc.

ICS8705

The ICS8705 is a highly versatile 1:8 Differen-

tial-to-LVCMOS/LVTTL Clock Generator and a

member of the HiPerClockS™family of High Per-

formance Clock Solutions from ICS. The ICS8705

has two selectable clock inputs. The CLK1,

nCLK1 pair can accept most standard differential input lev-

els. The single ended CLK0 input accepts LVCMOS or LVTTL

input levels.The ICS8705 has a fully integrated PLL and can

be configured as zero delay buffer, multiplier or divider and

has an input and output frequency range of 15.625MHz to

250MHz. The reference divider, feedback divider and output

divider are each programmable, thereby allowing for the fol-

lowing output-to-input frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2,

1:4, 1:8. The external feedback allows the device to achieve

“zero delay” between the input clock and the output clocks.

The PLL_SEL pin can be used to bypass the PLL for system

test and debug purposes. In bypass mode, the reference clock

is routed around the PLL and into the internal output dividers.

• 8 LVCMOS/LVTTL outputs, 7

Ω typical output impedance

• Selectable CLK1, nCLK1 or LVCMOS/LVTTL clock inputs

• CLK1, nCLK1 pair can accept the following differential

input levels: LVPECL, LVDS, LVHSTL, HCSL, SSTL

• CLK0 input accepts LVCMOS or LVTTL input levels

• Output frequency range: 15.625MHz to 250MHz

• Input frequency range: 15.625MHz to 250MHz

• VCO range: 250MHz to 500MHz

• External feedback for “zero delay” clock regeneration

with configurable frequencies

• Programmable dividers allow for the following output-to-input

frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8

• Fully integrated PLL

• Cycle-to-cycle jitter: 45ps (maximum)

• Output skew: CLK0, 65ps (maximum)

CLK1, nCLK1, 55ps (maximum)

• Static Phase Offset: 25 ±125ps (maximum), CLK0

• Full 3.3V or 2.5V operating supply

• Lead-Free package available

• Industrial temperature information available upon request

HiPerClockS™

ICS

32 31 30 29 28 27 26 25

9 10 11 12 13 14 15 16

1

2

3

4

5

6

7

8

24

23

22

21

20

19

18

17

32-Lead LQFP

7mm x 7mm x 1.4 mm

Y Package

Top View

Q5

GND

Q4

Q3

GND

Q2

SEL0

SEL1

CLK0

nc

CLK1

nCLK1

CLK_SEL

MR

ICS8705

PLL_SEL

CLK0

CLK1

nCLK1

CLK_SEL

FB_IN

SEL0

SEL1

SEL2

SEL3

MR

0

1

Q0

Q1

Q2

Q3

Q4

Q5

Q6

Q7

PLL

8:1, 4:1, 2:1, 1:1,

1:2, 1:4, 1:8

÷2, ÷4, ÷8, ÷16,

÷32

0

1