ICST ICS8431CM-11, ICS8431CM-11T Datasheet
Integrated
Circuit
Systems, Inc.
L VPECL F
ICS8431-11
255MHZ, LOW JITTER,
REQUENCY SYNTHESIZER
GENERAL DESCRIPTION
,&6
HiPerClockS™
510MHz providing an output frequency range of 95MHz to
255MHz. The output frequency can be programmed using the
parallel interface, M0 thru M8, to the configuration logic.
Spread spectrum clocking is programmed via the control
inputs SSC_CTL0 and SSC_CTL1.
Programmable features of the ICS8431-11 support four
operational modes. The four modes are spread spectrum
clocking (SSC), non-spread spectrum clock and two test
modes which are controlled by the SSC_CTL[1:0] pins. Unlike other synthesizers, the ICS8431-11 can immediately
change spread-spectrum operation without having to reset
the device.
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 incircuit 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 and the Fout divide by 2. This is useful
for characterizing the oscillator and internal dividers.
The ICS8431-11 is a general purpose clock
frequency synthesizer for IA64/32 application and
a member of the HiPerClockS™ family of High
Performance Clock Solutions from ICS. The VCO
operates at a frequency range of 190MHz to
FEATURES
• Fully integrated PLL
• Differential 3.3V LVPECL output
• Programmable PLL loop divider for generating a variety of
output frequencies.
• Crystal oscillator interface
• Spread Spectrum Clocking (SSC) fixed at 1/2% modulation
for environments requiring ultra low EMI
• Typical RMS cycle-to-cycle jitter 2.6 ps
• LVTTL / L VCMOS control inputs
• PLL bypass modes supporting in-circuit testing and on-chip
functional block characterization
• 3.3V supply voltage
• 28 lead SOIC
• 0°C to 85°C ambient operating temperature
BLOCK DIAGRAM PIN ASSIGNMENT
nP_LOAD
1
XTAL1
XTAL2
OSC
÷ 16
PHASE
DETECTOR
÷ M
PLL
VCO
÷ 2
FOUT
nFOUT
M0
M1
M2
M3
M4
M5
M6
M7
M8
SSC_CTL0
SSC_CTL1
VEE
TEST_I/O
VDD
2
3
4
5
6
7
8
9
10
11
12
13
14
ICS8431-11
TEST_I/O
M0:M8
ICS8431CM-11 www.icst.com/products/hiperclocks.html REV. A JULY 11, 2001
Configuration
Logic
nP_LOAD
SSC_CTL0
SSC
Control
Logic
SSC_CTL1
1
28-Lead SOIC
M Package
Top View
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VDDI
XTAL2
XTAL1
nc
nc
VDDA
VEE
MR
nc
VDDO
FOUT
nFOUT
VEE
Integrated
Circuit
Systems, Inc.
TABLE 1. PIN DESCRIPTIONS
rebmuNemaNepyTnoitpircseD
5-16M-0MtupnInwodlluP
8-68M-7MtupnIpulluP
11,01
21EEVrewoP.tuptuotsetdnaerocrofnipdnuorG
31O/ITSET
41DDVrewoP.tuptuotsetdnaerocrofnipylppusrewoP
51EEVrewoP.tuptuorofnipdnuorG
71,61TUOF,TUOFntuptuO
81ODDVrewoP.tuptuorofnipylppusrewoP
42,32,91cndesunU.noitcennocoN
02RMtupnInwodlluP.wolTUOFsecroF.retnuocMteseR
12EEVrewoP.nipdnuorG
22ADDVrewoP.nipylppusrewopLLP
62,522LATX,1LATXtupnI.tupnirotallicsolatsyrC
72IDDVrewoP.erocrofnipylppusrewoP
82DAOL_PntupnInwodlluP.slevelecafretniSOMCVL/LTTVL.tupnielbanehctalredividM
,0LTCCSS
1LTCCSS
tupnIpulluP.slevelecafretniSOMCVL/LTTVL.sniplortnocCCS
/tupnI
tuptuO
ICS8431-11
255MHZ, LOW JITTER,
L VPECL F
.cigol
REQUENCY SYNTHESIZER
fonoitsisnartHGIH-ot-WOLnodehctalataD.stupniredividM
.slevelecafretnisnipLTTVL/SOMCVL.tupniDAOL_Pn
fonoitsisnartHGIH-ot-WOLnodehctalataD.stupniredividM
.slevelecafretnisnipLTTVL/SOMCVL.tupniDAOL_Pn
.edomssapybLLPnitupnisademmargorP
.rezisehtnysehtrofsrevirdtuptuoniamerastuptuolaitnereffidesehT
LCEPVLdecnereferevitisopdetanimrethtiwelbitapmocerayehT
TABLE 2. PIN CHARACTERISTICS
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
NICecnaticapaCniPtupnI 4Fp
PULLUPRrotsiseRpulluPtupnI 15KΩ
NWODLLUPRrotsiseRnwodlluPtupnI 15KΩ
ICS8431CM-11 www.icst.com/products/hiperclocks.html REV. A JULY 11, 2001
2
Integrated
Circuit
Systems, Inc.
TABLE 3A. SSC CONTROL INPUT FUNCTION TABLE
L VPECL F
ICS8431-11
255MHZ, LOW JITTER,
REQUENCY SYNTHESIZER
stupnI
1LTC_CSS0LTC_CSS
00 lanretnIdelbasiDLATXf ÷ 23
01LLPdelbanE
10 lanretxEdelbasiDklCtseTtupnI
11LLPdelbasiD
O/I_TSET
ecruoS
CSS
23
23
.noitaziretcarahcdnagubedesuohnirofdesU:1ETON
stuptuO
,TUOF
TUOFn
LATXf ÷ 61
÷ M
MxLATXf
MxLATXf
Z-iHtnecreP½=rotcaFnoitaludoM;CSStluafeD
Z-iHnoitaludoMCSSoN
TABLE 3B. PROGRAMMABLE VCO FREQUENCY FUNCTION TABLE (NOTE 1)
ycneuqerFOCV
)zHM(
091091 010111110
191191 010111111
291291 011000000
391391 011000001
• • •••••••••
• • •••••••••
805805 111111100
905905 111111101
015015 111111110
tnuoCM
6528214623618421
8M7M6M5M4M3M2M1M0M
.latsyrczHM61asemussA:1ETON
sedoMlanoitarepO
O/I_TSET
NdnaM,rotallicso,rotallicsO;ssapybLLP
1ETON.edomtsetsredivid
,edoMssapyBLLP
zHM1( ≤ klCtseT ≤ 1ETON;)zHM002
ICS8431CM-11 www.icst.com/products/hiperclocks.html REV. A JULY 11, 2001
3
Integrated
Circuit
Systems, Inc.
L VPECL F
REQUENCY SYNTHESIZER
ICS8431-11
255MHZ, LOW JITTER,
ABSOLUTE MAXIMUM RATINGS
Supply Voltage 4.6V
Inputs -0.5V to VDD + 0.5V
Outputs -0.5V to VDDO + 0.5V
Ambient Operating T emperature 0°C to 85°C
Storage T emperature -65°C to 150°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings
are stress specifications only and functional operation of product at these condition or any conditions beyond those listed in
the
DC Characteristics
periods may affect product reliability.
or
AC Characteristics
is not implied. Exposure to absolute maximum rating conditions for extended
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDA = VDDI = VDDO = 3.3V±5%, TA = 0°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
DDVegatloVylppuSrewoP 531.33.3564.3V
ODDVegatloVylppuSrewoPtuptuO 531.33.3564.3V
ADDVegatloVylppuSrewoPgolanA 531.33.3564.3V
IDDVegatloVylppuSrewoPtupnI 531.33.3564.3V
EEI 041Am
TABLE 4B. LVCMOS / LVTTL DC CHARACTERISTICS, VDD = VDDA = VDDI = VDDO = 3.3V±5%, TA = 0°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
,0LTC_CSS,8M:0M
HIVegatloVhgiHtupnI
LIVegatloVwoLtupnI
HIItnerruChgiHtupnI
LIItnerruCwoLtupnI
,6M:0M
,6M:0M
,RM,1LTC_CSS
DAOL_Pn,O/I_TSET
,0LTC_CSS,8M:0M
,RM,1LTC_CSS
DAOL_Pn,O/I_TSET
,0LTC_CSS,8M,7M
OI_TSET,1LTC_CSS
RM,DAOL_Pn
,0LTC_CSS,8M,7M
OI_TSET,1LTC_CSS
RM,DAOL_Pn
V531.3 ≤ DDV ≤ V564.32 3.0+DDVV
V531.3 ≤ DDV ≤ V564.33.0-8.0V
V564.3=NIV=DDV5Aµ
V564.3=NIV=DDV051Aµ
V0=NIV,V564.3=DDV051-Aµ
V0=NIV,V564.3=DDV5-Aµ
TABLE 4C. LVPECL DC CHARACTERISTICS, VDD = VDDA = VDDI = VDDO = 3.3V±5%, TA = 0°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
HOV1ETON;egatloVhgiHtuptuO 82.1-ODDV89.0-ODDVV
LOVegatloVwoLtuptuO1ETON;0.2-ODDV7.1-ODDVV
GNIWSVgniwSegatloVtuptuOkaeP-ot-kaeP006007058Vm
05htiwdetanimrettuptuO:1ETON Ω .V2-ODDVot
ICS8431CM-11 www.icst.com/products/hiperclocks.html REV. A JULY 11, 2001
4
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