ICS8431I-01
200MHZ, LOW JITTER,
CRYSTAL OSCILLATOR-TO-3.3V LVPECLFREQUENCY SYNTHESIZER
Integrated
Circuit
Systems, Incꢀ
GENERAL DESCRIPTION
FEATURES
The ICS8431I-01 is a general purpose clock • Fully integrated PLL
frequency synthesizer for IA64/32 applications
• Differential 3.3V LVPECLoutput
HiPerClockS™
and a member of the HiPerClockS™ family of High
Performance Clock Solutions from ICS. The
ICS8431I-01 consists of one independent low
• Crystal oscillator interface
• Output frequency of 200MHz
• 48% to 52% duty cycle
bandwidth PLL timing channel. A 16.666MHz crystal is used
as the input to the on-chip oscillator. The M divide is config-
ured to produce a fixed output frequency of 200MHz.
• Spread Spectrum Clocking (SSC) fixed at 1/2% modulation
for environments requiring ultra low EMI. Typical10dB EMI
reduction can be achieved with spread spectrum modulation
Programmable features of the ICS8431I-01 support four
operational modes. The four modes are spread spectrum
clocking (SSC), non-spread spectrum clocking and two test
modes which are controlled by the SSC_CTL[1:0] pins. Un-
like other synthesizers, the ICS8431I-01 can immediately
change spread-spectrum operation without having to reset
the device.
• PLLbypass modes supporting in-circuit testing and on-chip
functional block characterization
• Cycle-to-cycle jitter: 25ps (maximum)
• 3.3V supply voltage
In SSC mode, the output clock is modulated in order to
achieve a reduction in EMI. In one of the PLL bypass test
modes, the PLL is disconnected as the source to the
differential output allowing an external source to be
connnected to the TEST_I/O pin. This is useful for in-
circuit testing and allows the differential output to be driven
at a lower frequency throughout the system clock tree. In the
other PLL bypass mode, the oscillator divider is used as the
source to both the M divide and the Fout divide by 2. This is
useful for characterizing the oscillator and internal dividers.
• -40° to 85°C ambient operating temperature
BLOCK DIAGRAM
PIN ASSIGNMENT
nc
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
nc
XTAL1
OSC
nc
nc
2
3
VCC
XTAL2
XTAL1
nc
XTAL2
nc
nc
4
5
÷ 16
nc
nc
6
7
nc
VCCA
VEE
nc
8
PLL
nc
9
RESERVED
nc
PHASE
DETECTOR
SSC_CTL0
SSC_CTL1
VEE
10
11
12
13
14
VCCO
FOUT
nFOUT
VEE
VCO
÷ 2
TEST_I/O
VCC
FOUT
nFOUT
÷ M
ICS8431I-01
TEST_I/O
28-Lead SOIC
7.5mm x 18.05mm x 2.25mm package body
SSC_CTL0
SSC
M Package
Top View
Control
SSC_CTL1
Logic
8431EMI-01
www.icst.com/products/hiperclocks.html
REV. A FEBRUARY 4, 2003
1