LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS
FANOUT BUFFER
ICS83908I-02
IDT™ / ICS™ LVCMOS FANOUT BUFFER 1 ICS83908AGI-02 REV. B JULY 24, 2007
PRELIMINARY
GENERAL DESCRIPTION
The ICS83908I-02 is a low skew, high performance
1-to-8 Crystal Oscillator/3.3V LVCMOS-to-3.3V
LVCMOS fanout buffer and a member of the
HiPerClockS™ family of High Performance Clock
Solutions from IDT. The ICS83908I-02 has selectable
single ended clock or two crystal-oscillator inputs. There is an
output enable to disable the outputs by placing them into a high-
impedance state.
Guaranteed output and part-to-part skew characteristics make
the ICS83908I-02 ideal for those applications demanding well
defined performance and repeatability.
FEATURES
•Eight LVCMOS/LVTTL outputs
(19Ω typical output impedance)
•Two Crystal oscillator input pairs
One LVCMOS/LVTTL clock input
•Crystal input frequencry range: 10MHz - 40MHz
•Output frequency: 200MHz (typical) CLK0
•Output Skew: TBD
•Part to Part Skew: TBD
• RMS phase jitter @ 25MHz (100Hz - 1MHz):
0.22ps (typical) VDD = VDDO = 3.3V
Offset Noise Power
100Hz ............. -111.4 dBc/Hz
1kHz ............. -139.9 dBc/Hz
10kHz ............. -157.3 dBc/Hz
100kHz ............. -157.5 dBc/Hz
•Supply Voltage Modes:
(Core/Output)
3.3V/3.3V
3.3V/2.5V
3.3V/1.8V
2.5V/2.5V
2.5V/1.8V
•-40°C to 85°C ambient operating temperature
•Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
HiPerClockS™
ICS
OE
CLK_SEL0
CLK_SEL1
CLK0
Q0
Q7
OSC
OSC
0 0
0 1
1 0
1 1
Pullup
ICS83908I-02
24-Lead, 173-MIL TSSOP
4.4mm x 7.8mm x 0.92mm
body package
G Package
Top View
VDD
XTAL_IN0
XTAL_OUT0
VDDO
Q0
Q1
GND
Q2
Q3
VDDO
CLK_SEL0
CLK0
GND
XTAL_IN1
XTAL_OUT1
VDDO
Q7
Q6
GND
Q5
Q4
VDDO
CLK_SEL1
OE
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Pulldown
Pulldown
XTAL_IN0
XTAL_OUT0
XTAL_IN1
XTAL_OUT1
Pulldown
8 LVCMOS Outputs
BLOCK DIAGRAM
PIN ASSIGNMENT
The Preliminary Information presented herein represents a product in pre-production. The noted characteristics are based on initial product characterization
and/or qualification. Integrated Device Technology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice.
IDT™ / ICS™ LVCMOS FANOUT BUFFER 2 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
TABLE 1. PIN DESCRIPTIONS
TABLE 2. PIN CHARACTERISTICS
rebmuNemaNepyTnoitpircseD
1V
DD
rewoP.nipylppuseroC
3,2 ,0NI_LATX
0TUO_LATX tupnI .tupniehtsi0NI_LATX.ecafretnirotallicsolatsyrC
.tuptuoehts
i0TUO_LATX
12,51,01,4V
ODD
rewoP.snipylppustuptuO
,8,6,5
,71,61,9
02,91
,2Q,1Q,0Q
,5Q,4Q,3Q
7Q,6Q
tuptuO .slevelecafretniLTTVL/SOMCVL.stu
ptuokcolcdedne-elgniS
42,81,7DNGrewoP.dnuorgylppusrewoP
,11
41
,0LES_KLC
1LES_KLC tupnInwodlluP .elbaTnoitcnuFec
nerefeRtupnI,3elbaTeeS.stupnitceleskcolC
.slevelecafretniLTTVL/SOMCVL
210KLCtupnInwodlluP.slevelecafretniLT
TVL/SOMCVL.tupnikcolcdedne-elgniS
31EOtupnIpulluP .etatsecnadepmiHGIHnierastuptuo,WOLnehW.elbanetuptuO
.sle
velecafretniLTTVL/SOMCVL.evitcaerastuptuo,HGIHnehW
32,22 ,1TUO_LATX
1NI_LATX tupnI .tupniehtsi1NI_LATX.eca
fretnirotallicsolatsyrC
.tuptuoehtsi1TUO_LATX
:ETON pulluP dna nwodlluP .seulavlacipytrof,scitsiretcarahCni
P,2elbaTeeS.srotsisertupnilanretniotrefer
TABLE 3. INPUT REFERENCE FUNCTION TABLE
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
C
NI
ecnaticapaCtupnI 4Fp
R
PULLUP
rotsiseRpulluPtupnI 15kΩ
R
NWODLLUP
rotsiseRnwodlluPtupnI 15kΩ
C
DP
ecnaticapaCnoitapissiDrewoP
)tuptuorep(
V
ODD
V564.3=7Fp
V
ODD
V526.2=7Fp
V
ODD
V2=6Fp
R
TUO
ecnadepmItuptuO
V
ODD
%5±V3.3=91Ω
V
ODD
%5±V5.2=12Ω
V
ODD
V2.0±V8.1=23Ω
stupnIlortnoC ecnerefeR
1LES_KLC0LES_KLC
00 )tluafed(0LATX
01 1LATX
10 0KLC
11 0KLC
IDT™ / ICS™ LVCMOS FANOUT BUFFER 3 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
DD 4.6V
Inputs, VI-0.5V to VDD + 0.5 V
Outputs, V
O-0.5V to VDDO + 0.5V
Package Thermal Impedance, θ
JA 84.6°C/W (0 mps)
Storage Temperature, T
STG -65°C to 150°C
NOTE: Stresses beyond those listed under Absolute
Maximum Ratings may cause permanent damage to the
device. These ratings are stress specifications only. Functional op-
eration of product at these conditions or any conditions beyond
those listed in the DC Characteristics or AC Character istics is not
implied. Exposure to absolute maximum rating conditions for ex-
tended periods may affect product reliability.
TABLE 4A. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDO = 3.3V±5%, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
DD
egatloVylppuSeroC 531.33.3564.3V
V
ODD
egatloVylppuStuptuO 531.33.3564.3V
I
DD
tnerruCylppuSrewoP detcelesxLATX&daoLoN52Am
detceles0KLC&daoLoN0Am
I
ODD
tnerruCylppuStuptuOdetceles0KLC&daoLoN0Am
TABLE 4B. POWER SUPPLY DC CHARACTERISTICS, VDD = 3.3V±5%, VDDO = 2.5V±5%, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
DD
egatloVylppuSeroC 531.33.3564.3V
V
ODD
egatloVylppuStuptuO 573.25.2526.2V
I
DD
tnerruCylppuSrewoP detcelesxLATX&daoLoN52Am
detceles0KLC&daoLoN0Am
I
ODD
tnerruCylppuStuptuOdetceles0KLC&daoLoN0Am
TABLE 4C. POWER SUPPLY DC CHARACTERISTICS, VDD = 3.3V±5%, VDDO = 1.8V±0.2V, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
DD
egatloVylppuSeroC 531.33.3564.3V
V
ODD
egatloVylppuStuptuO 6.18.10.2V
I
DD
tnerruCylppuSrewoP detcelesxLATX&daoLoN52Am
detceles0KLC&daoLoN0Am
I
ODD
tnerruCylppuStuptuOdetceles0KLC&daoLoN0Am
TABLE 4D. POWER SUPPLY DC CHARACTERISTICS, VDD = VDDO = 2.5V±5%, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
DD
egatloVylppuSeroC 573.25.2526.2V
V
ODD
egatloVylppuStuptuO 573.25.2526.2V
I
DD
tnerruCylppuSrewoP detcelesxLATX&daoLoN51Am
detceles0KLC&daoLoN0Am
I
ODD
tnerruCylppuStuptuOdetceles0KLC&daoLoN0Am
IDT™ / ICS™ LVCMOS FANOUT BUFFER 4 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
TABLE 4F. LVCMOS/LVTTL DC CHARACTERISTICS, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
HI
egatloVhgiHtupnI V
DD
%5±V3.3=2.2V
DD
3.0+V
V
DD
%5±V5.2=6.1V
DD
3.0+V
V
LI
egatloVwoLtupnI V
DD
%5±V3.3=3.0-3.1V
V
DD
%5±V5.2=3.0-9.0V
I
HI
tnerruChgiHtupnI
,0KLC
1:0LES_KLC V
DD
%5±V5.2roV3.3=051Aµ
EOV
DD
%5±V5.2roV3.3=5Aµ
I
LI
tnerruCwoLtupnI
,0KLC
1:0LES_KLC V
DD
%5±V5.2roV3.3=5-Aµ
EOV
DD
%5±V5.2roV3.3=051-Aµ
V
HO
hgiHtuptuOegatloV
V
ODD
1ETON;%5±V3.3=6.2V
V
ODD
1ETON;%5±V5.2=8.1V
V
ODD
1ETON;V2.0±V8.1=2.1V
V
LO
egatloVwoLtuptuO
V
ODD
1ETON;%5±V3.3=6.0V
V
ODD
1ETON;%5±V5.2=5.0V
V
ODD
1ETON;V2.0±V8.1=4.0V
05htiwdetanimretstuptuO:1ETON ΩVot
ODD
.smargaid"tiucriCtseTdaoL",noitcestnemerusaeMretemaraPeeS.2/
TABLE 5. CRYSTAL CHARACTERISTICS
retemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
tuc/noitallicsOfoedoM latnemadnuF
ycneuqerF 0104zHM
)RSE(ecnats
iseRseireStnelaviuqE 05 Ω
ecnaticapaCtnuhS 7Fp
leveLevirD 1Wm
TABLE 4E. POWER SUPPLY DC CHARACTERISTICS, VDD = 2.5V±5%, VDDO = 1.8V±0.2V, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
V
DD
egatloVylppuSeroC 573.25.2526.2V
V
ODD
egatloVylppuStuptuO 6.18.10.2V
I
DD
tnerruCylppuSrewoP detcelesxLATX&daoLoN51Am
detceles0KLC&daoLoN0Am
I
ODD
tnerruCylppuStuptuOdetceles0KLC&daoLoN0Am
IDT™ / ICS™ LVCMOS FANOUT BUFFER 5 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
TABLE 6A. AC CHARACTERISTICS, VDD = VDDO = 3.3V ± 5%, TA = -40°C TO 85°C
TABLE 6B. AC CHARACTERISTICS, VDD = 3.3V ± 5%, VDDO = 2.5V ± 5%, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
f
XAM
ycneuqerFtuptuO
lanretxE/w
LATX 0104zHM
KLClanretxE/w002zHM
pt
HL
;hgiH-ot-woL,yaleDnoitagaporP
1ETON 2sn
t)o(ks2ETON;wekStuptuO DBTsp
t)pp(ks3,2ETON;wekStraP-ot-traP DBTsp
t)Ø(ti
j;modnaR,rettiJesahPSMR
4,2ETON )zHM1-zH001(,zHM5222.0sp
t
R
t/
F
emiTllaF/esiRtuptuO%08ot%02754sp
cdoelcyCytuDtuptuO 05%
t
NE
5ETON;emiTelbanEtuptuO 01sn
t
SID
5ETON;emiTelbasiDtuptuO 8sn
VmorfderusaeM:1ETON
DD
Vottupniehtfo2/
ODD
.tuptuoehtfo2/
.56dradnatSCEDEJhtiwecnadroccanidenifedsiretemarapsihT:2ETON
dnasegatlovylppusemasehtagn
itareposecivedtnereffidnostuptuoneewtebwekssadenifeD:3ETON
Vtaderusaemsituptuoeht,ecivedhcaenotupnifoe
pytemasehtgnisU.snoitidnocdaollauqehtiw
ODD
.2/
.desuecruostupniehtnotnednepedsirettijesahP:4ETON
.noitcudorpnidetsettoN.noitaziretcarahcybdeetnara
ugerasretemarapesehT:5ETON
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
f
XAM
ycneuqerFtuptuO
lanretxE/w
LATX 0104zHM
KLClanretxE/w002zHM
pt
HL
;hgiH-ot-woL,yaleDnoitagaporP
1ETON 2.2sn
t)o(ks2ETON;wekStuptuO DBTsp
t)pp(ks3,2ETON;wekStraP-ot-traP DBTsp
t)Ø(
tij ;modnaR,rettiJesahPSMR
4,2ETON )zHM1-zH001(,zHM5212.0sp
t
R
t/
F
emiTllaF/esiRtuptuO%08ot%02364sp
cdoelcyCytuDtuptuO 05%
t
NE
5ETON;emiTelbanEtuptuO 01sn
t
SID
5ETON;emiTelbasiDtuptuO 8sn
VmorfderusaeM:1ETON
DD
Vottupniehtfo2/
ODD
.tuptuoehtfo2/
.56dradnatSCEDEJhtiwecnadroccanidenifedsiretemarapsihT:2ETON
dnasegatlovylppusemasehtagn
itareposecivedtnereffidnostuptuoneewtebwekssadenifeD:3ETON
Vtaderusaemsituptuoeht,ecivedhcaenotupnifoe
pytemasehtgnisU.snoitidnocdaollauqehtiw
ODD
.2/
.desuecruostupniehtnotnednepedsirettijesahP:4ETON
.noitcudorpnidetsettoN.noitaziretcarahcybdeetnara
ugerasretemarapesehT:5ETON
IDT™ / ICS™ LVCMOS FANOUT BUFFER 6 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
TABLE 6D. AC CHARACTERISTICS, VDD = VDDO = 2.5V ± 5%, TA = -40°C TO 85°C
TABLE 6C. AC CHARACTERISTICS, VDD = 3.3V ± 5%, VDDO = 1.8V±0.2V, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
f
XAM
ycneuqerFtuptuO
lanretxE/w
LATX 0104zHM
KLClanretxE/w002zHM
pt
HL
;hgiH-ot-woL,yaleDnoitagaporP
1ETON 5.2sn
t)o(ks2ETON;wekStuptuO DBTsp
t)pp(ks3,2ETON;wekStraP-ot-traP DBTsp
t)Ø(
tij ;modnaR,rettiJesahPSMR
4,2ETON )zHM1-zH001(,zHM5222.0sp
t
R
t/
F
emiTllaF/esiRtuptuO%08ot%02784sp
cdoelcyCytuDtuptuO 05%
t
NE
5ETON;emiTelbanEtuptuO 01sn
t
SID
5ETON;emiTelbasiDtuptuO 8sn
VmorfderusaeM:1ETON
DD
Vottupniehtfo2/
ODD
.tuptuoehtfo2/
.56dradnatSCEDEJhtiwecnadroccanidenifedsiretemarapsihT:2ETON
dnasegatlovylppusemasehtagn
itareposecivedtnereffidnostuptuoneewtebwekssadenifeD:3ETON
Vtaderusaemsituptuoeht,ecivedhcaenotupnifoe
pytemasehtgnisU.snoitidnocdaollauqehtiw
ODD
.2/
.desuecruostupniehtnotnednepedsirettijesahP:4ETON
.noitcudorpnidetsettoN.noitaziretcarahcybdeetnara
ugerasretemarapesehT:5ETON
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
f
XAM
ycneuqerFtuptuO
lanretxE/w
LATX 0104zHM
KLClanretxE/w002zHM
pt
HL
;hgiH-ot-woL,yaleDnoitagaporP
1ETON 3.2sn
t)o(ks2ETON;wekStuptuO DBTsp
t)pp(ks3,2ETON;wekStraP-ot-traP DBTsp
t)Ø(
tij ;modnaR,rettiJesahPSMR
4,2ETON )zHM1-zH001(,zHM5292.0sp
t
R
t/
F
emiTllaF/esiRtuptuO%08ot%02074sp
cdoelcyCytuDtuptuO 05%
t
NE
5ETON;emiTelbanEtuptuO 01sn
t
SID
5ETON;emiTelbasiDtuptuO 8sn
VmorfderusaeM:1ETON
DD
Vottupniehtfo2/
ODD
.tuptuoehtfo2/
.56dradnatSCEDEJhtiwecnadroccanidenifedsiretemarapsihT:2ETON
dnasegatlovylppusemasehtagn
itareposecivedtnereffidnostuptuoneewtebwekssadenifeD:3ETON
Vtaderusaemsituptuoeht,ecivedhcaenotupnifoe
pytemasehtgnisU.snoitidnocdaollauqehtiw
ODD
.2/
.desuecruostupniehtnotnednepedsirettijesahP:4ETON
.noitcudorpnidetsettoN.noitaziretcarahcybdeetnara
ugerasretemarapesehT:5ETON
IDT™ / ICS™ LVCMOS FANOUT BUFFER 7 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
TABLE 6E. AC CHARACTERISTICS, VDD = 2.5V ± 5%, VDDO = 1.8V±0.2V, TA = -40°C TO 85°C
lobmySretemaraPsnoitidnoCtseTmuminiMlacipyTmumixaMstinU
f
XAM
ycneuqerFtuptuO
lanretxE/w
LATX 0104zHM
KLClanretxE/w002zHM
pt
HL
;hgiH-ot-woL,yaleDnoitagaporP
1ETON 6.2sn
t)o(ks2ETON;wekStuptuO DBTsp
t)pp(ks3,2ETON;wekStraP-ot-traP DBTsp
t)Ø(
tij ;modnaR,rettiJesahPSMR
4,2ETON )zHM1-zH001(,zHM523.0sp
t
R
t/
F
emiTllaF/esiRtuptuO%08ot%02815sp
cdoelcyCytuDtuptuO 05%
t
NE
5ETON;emiTelbanEtuptuO 01sn
t
SID
5ETON;emiTelbasiDtuptuO 8sn
VmorfderusaeM:1ETON
DD
Vottupniehtfo2/
ODD
.tuptuoehtfo2/
.56dradnatSCEDEJhtiwecnadroccanidenifedsiretemarapsihT:2ETON
dnasegatlovylppusemasehtagn
itareposecivedtnereffidnostuptuoneewtebwekssadenifeD:3ETON
Vtaderusaemsituptuoeht,ecivedhcaenotupnifoe
pytemasehtgnisU.snoitidnocdaollauqehtiw
ODD
.2/
.desuecruostupniehtnotnednepedsirettijesahP:4ETON
.noitcudorpnidetsettoN.noitaziretcarahcybdeetnara
ugerasretemarapesehT:5ETON
IDT™ / ICS™ LVCMOS FANOUT BUFFER 8 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
25MHz
RMS Phase Jitter (Random)
100Hz to 1MHz = 0.22ps (typical)
OFFSET FREQUENCY (HZ)
NOISE POWER dBc
Hz
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
-170
-180
-190
100 1k 10k 100k 1M
➤
TYPICAL PHASE NOISE AT 25MHZ @ 3.3V
Raw Phase Noise Data
IDT™ / ICS™ LVCMOS FANOUT BUFFER 9 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
PARAMETER MEASUREMENT INFORMATION
Qx
Qy
PART 1
PART 2
tsk(pp)
V
DDO
2
V
DDO
2
2.5V CORE/2.5V OUTPUT LOAD AC TEST CIRCUIT
3.3V CORE/2.5V OUTPUT LOAD AC TEST CIRCUIT3.3V CORE/3.3V OUTPUT LOAD AC TEST CIRCUIT
SCOPE
Qx
LVCMOS
GND
1.65V±5%
-1.65V±5%
3.3V CORE/1.8V OUTPUT LOAD AC TEST CIRCUIT
2.5V CORE/1.8V OUTPUT LOAD AC TEST CIRCUIT PART-TO-PART SKEW
SCOPE
Qx
LVCMOS
GND
2.05V±5%
-1.25V±5%
VDD,
VDDO
VDD
SCOPE
Qx
LVCMOS
GND
1.25V±5%
-1.25V±5%
VDD,
VDDO
VDDO
1.25V±5%
SCOPE
Qx
LVCMOS
GND
2.4V±0.065V
VDDO
-0.9V±0.1V
VDD
0.9V±0.1V
SCOPE
Qx
LVCMOSGND
1.6V±0.025V
VDDO
-0.9V±0.1V
VDD
0.9V±0.1V
IDT™ / ICS™ LVCMOS FANOUT BUFFER 10 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
OUTPUT RISE/FALL TIME PROPAGATION DELAY
OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
Q0:Q7
tPERIOD
tPW
tPERIOD
odc =
V
DDO
2
x 100%
tPW
tpLH tpHL
VDDO
2
VDD
2
VDDO
2
VDD
2
CLK0
Q0:Q7
Clock
Outputs
20%
80% 80%
20%
t
R
t
F
IDT™ / ICS™ LVCMOS FANOUT BUFFER 11 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
APPLICATION INFORMATION
FIGURE 1. Crystal Input Interface
CRYSTAL INPUT INTERFACE
A crystal can be characterized for either series or parallel mode
operation. The ICS83908I-02 has a built-in crystal oscillator
circuit. This interface can accept either a series or parallel
crystal without additional components and generate fre-
quencies with accuracy suitable for most applications. Additional
accuracy can be achieved by adding two small capacitors C1
and C2 as shown in Figure 1. Typical results using parallel 18pF
crystals are shown in Table 5.
C1
15p
X1
18pF Parallel Crystal
C2
15p
XTAL_OUT
XTAL_IN
LVCMOS TO XTAL INTERFACE
The XTAL_IN input can accept a single-ended LVCMOS signal
through an AC coupling capacitor. A general interface diagram is
shown in Figure 2. The XTAL_OUT pin can be left floating. The
input edge rate can be as slow as 10ns. For LVCMOS inputs, it is
recommended that the amplitude be reduced from full swing to
half swing in order to prevent signal interference with the power
rail and to reduce noise. This configuration requires that the output
FIGURE 2. GENERAL DIAGRAM FOR LVCMOS DRIVER TO XTAL INPUT INTERFACE
impedance of the driver (Ro) plus the series resistance (Rs) equals
the transmission line impedance. In addition, matched termination
at the crystal input will attenuate the signal in half. This can be
done in one of two ways. First, R1 and R2 in parallel should equal
the transmission line impedance. For most 50Ω applications, R1
and R2 can be 100Ω. This can also be accomplished by removing
R1 and making R2 50Ω.
R2
Zo = 50
VDD
Ro
Zo = Ro + Rs
R1
VDD
XTA L _ I N
XTA L _ O U T
.1uf
Rs
IDT™ / ICS™ LVCMOS FANOUT BUFFER 12 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
INPUTS:
CLK INPUT
For applications not requiring the use of the test clock, it can be
left floating. Though not required, but for additional protection, a
1kΩ resistor can be tied from the CLK input to ground.
CRYSTAL INPUTS
For applications not requiring the use of the crystal oscillator
input, both XTAL_IN and XTAL_OUT can be left floating. Though
not required, but for additional protection, a 1kΩ resister can be
tied from XTAL_IN to ground.
LVCMOS CONTROL PINS
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS
OUTPUTS:
LVCMOS OUTPUTS
All unused LVCMOS output can be left floating. There should be
no trace attached.
IDT™ / ICS™ LVCMOS FANOUT BUFFER 13 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
RELIABILITY INFORMATION
TRANSISTOR COUNT
The transistor count for ICS83908I-02 is: 277
TABLE 7. θ
JAVS. AIR FLOW TABLE FOR 24 LEAD TSSOP
θθ
θθ
θJA by Velocity (Meters per Second)
0 1 2.5
Multi-Layer PCB, JEDEC Standard Test Boards 84.6°C/W 80.3°C/W 78.1°C/W
IDT™ / ICS™ LVCMOS FANOUT BUFFER 14 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
PACKAGE OUTLINE - G SUFFIX FOR 24 LEAD TSSOP
TABLE 8. PACKAGE DIMENSIONS
REFERENCE DOCUMENT: JEDEC PUBLICATION 95, MO-153
LOBMYS sretemilliM
muminiMmumixaM
N42
A--02.1
1A50.051.0
2A08.050.1
b91.003.0
c90.002.0
D07.709.7
ECISAB04.6
1E03.405.4
eCISAB56.0
L5
4.057.0
α°0°8
aaa--01.0
IDT™ / ICS™ LVCMOS FANOUT BUFFER 15 ICS83908AGI-02 REV. B JULY 24, 2007
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology, Incorporated (IDT) assumes no responsibility for either its use or for
infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial and
industrial applications. Any other applications such as those requiring high reliability or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT
reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.
TABLE 9. ORDERING INFORMATION
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0938SCIDBTPOSSTdaeL42leer&epat0052C°58otC°04-
FL20-IGA80938SCIL20IA80938SCIPOSST"eerF-daeL"daeL42ebutC°58otC°0
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TFL20-IGA80938SCIL20IA80938SCIPOSST"eerF-daeL"daeL42leer&epat0052C°58otC°04-
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Innovate with IDT and accelerate your future networks. Contact:
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England
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© 2007 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT, the IDT logo, ICS and HiPerClockS are trademarks
of Integrated Device Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be
trademarks or registered trademarks used to identify products or services of their respective owners.
Printed in USA
ICS83908I-02
LOW SKEW, 1-TO-8 CRYSTAL-TO-LVCMOS FANOUT BUFFER PRELIMINARY
