PRELIMINARY
ICS843002-31
Integrated
Circuit
Systems, Inc.
700MHZ FEMTOCLOCKS™VCXO BASED
FREQUENCY TRANSLATOR AND JITTER ATTENUATOR
GENERAL DESCRIPTION
FEATURES
The ICS843002-31 is a member of the • Outputs:
ICS
HiPerClockS™
HiperClockS™ family of high performance clock
• Two high frequency differential LVPECL outputs
Output frequency: up to 700MHz
solutions from ICS. This monolithic device is a
high-performance, PLL-based synchronous
clock generator and jitter attenuation circuit.The
• One LVCMOS/LVTTL VCXO PLL output with output
enable
ICS843002-31 contains two clock multiplication stages that
are cascaded in series.The first stage is a VCXO-based PLL
that is optimized to provide reference clock jitter attenuation,
to be jitter tolerant, and to provide a stable reference clock
for the second multiplication stage. The second stage is the
proprietary ICS FemtoClock™circuit which is a high-frequency,
sub-picosecond clock multiplier.
• One Reference clock output with output enable
• One LOCK detect output
• Input mux supports 3 selectable inputs: one differential
input pair and two LVCMOS/LVTTL input clocks
• 13-bitVCXO PLL feedback and reference dividers provide
wide range of frequency translation ratio options
The VCXO PLL has an on-chip VCXO circuit that uses an • FemtoClock frequency multiplier supports rate of:
external, inexpensive pullable crystal in the 17.5 to 25MHz
range. The PLL includes 13 bit reference and feedback
dividers supporting complex PLL multiplication ratios and
input reference clock rates as low as 2.3kHz. External loop
filter components are used (two resistors and two capacitors)
to achieve the low loop bandwidth needed for jitter atten-
uation of a recovered data clock.
560MHz - 700MHz
• ‘Lock Detect’ output reports lock status of VCXO PLL
• VCXO PLL circuit provides jitter attenuation with
loop bandwidth of 250Hz and below (user adjustable)
• RMS phase jitter, random at 12kHz to 20MHz:
<1ps (design target)
• 3.3V supply voltage
The FemtoClock circuit can multiply the VCXO crystal
frequency by a factor of 28 or 32 (selectable) and provide a
clock output of up to 700MHz.
• 0°C to 70°C ambient operating temperature
• Industrial temperature information available upon request
• Available in both standard and lead-free RoHS-compliant
packages
Clock Input/Output Configuration:
• Clock Inputs - one differential pair, two singled ended
(mux selected)
• Differential input pair can support LVPECL, LVDS,
LVHSTL, SSTL, HCSL or single-ended LVCMOS
or LVTTL levels
PIN ASSIGNMENT
• Singled ended inputs can support LVCMOS or
LVTTL levels
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
• Clock Outputs, FemtoClockS two LVPECL pairs
(selectable output dividers)
1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
VEE
LF1
LF0
2
REF_CLK
VCLK
LOCK
VCCO_CMOS
nQB
• Clock Output, VCXO – one single ended output
(at VCXO crystal frequency)
3
ISET
VEE
4
5
NV1
• Clock Output, other – VCXO reference clock
6
NV0
ICS843002-31
64-LeadTQFP, EPAD
10mm x 10mm x 1.0mm
package body
7
QB
VCC
8
VEE
MR
Example Applications:
9
nQA
CLK0
nCLK0
OE_REF
CLK1
VCC
• SONET/SDH line card clock generator (up to 622.08MHz
for OC-48) using 8kHz frame clock as input reference
10
11
QA
Y package
TopView
VCCO_PECL
MP
12
13
14
• Jitter attenuation of a recovered communications clock
NPB0
NPB1
NPB2
VCCA
• Complex-ratio clock frequency translation between
various communication protocols, such as:
• For telecom, OC-12 to E3 rate conversion, 622.08MHz
to 34.368MHz, PLL ratio of 179/32
SEL1
SEL0
CLK2
15
16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
• For digital video, ITU-R601 to SMPTE 252M/59.94,
27MHz to 74.17582MHz, PLL ratio of 250/91
The Preliminary Information presented herein represents a product in prototyping or pre-production.The noted characteristics are based on initial
product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications without notice.
843002CY-31
www.icst.com/products/hiperclocks.html
REV.B NOVEMBER 22, 2005
1