© 2003 Fairchild Semiconductor Corporation DS500655 www.fairchildsemi.com
March 2002
Revised May 2003
FIN1108 • FIN1108T (Preliminary) LVDS 8 Port High Speed Repeater
FIN1108 FIN1108T (Preliminary)
LVDS 8 Port High Speed Repeater
General Description
This 8 port repeater is designed for high speed intercon-
nects utilizing Low Voltage Differential Signaling (LVDS)
technology.
The FIN 11 08 acce pts and outputs LVDS le vels w ith a ty pi-
cal differen tial outp ut swing of 330 mV which p rovides low
EMI at ultra low power dissipation even at high frequen-
cies. The FIN1108 provides a VBB reference for AC cou-
pling on the inputs. In addition the FIN1108 can directly
accept LVPECL, HSTL, and SSTL-2 for translation to
LVDS.
The FIN1108T has inte rnal term ination across the receiver
inputs for reduced part count, reduced stub length and bet-
ter noise immu nity. See Applications section.
Features
Greater than 800 Mbps data rate
3.3V power supply operation
3.5 ps maximum random jitter and 135 ps maximum
deterministic jitter
Wide rail-to-rail common mode range
LVDS receiver inputs accept LVPECL, HSTL, and
SSTL-2 directly
Ultra low power consumption
20 ps typical channe l -to-c ha nn el skew
Power off protection
> 7.5 kV HBM ESD Protection
Meets or exceeds the TIA/EIA-644-A LVDS standard
Available in space saving 48-lead TSSOP package
Open circuit fail safe protection
VBB reference output
FIN1 108T (RT) features Internal Termination Resistors
Ordering Code:
Devices also available in Tape and Reel. S pecify by ap pending su ffix letter “X ” to th e ordering co de.
Order Number Package Number Package Description
FIN1108MTD MTD48 48-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1mm Wide
FIN1108TMTD
(Preliminary) MTD48 48-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1mm Wide
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FIN1108 FIN1108T (Preliminary)
Pin Descriptions
Function Table
H = HIGH Logi c Level
L = LOW Logic Level
X = Don’t Care
Z = High Impeda nc e
Connection Diagram
Functional Diagram
Pin Name Description
RIN1+, RIN2+,
RIN3+, RIN4+,
RIN5+, RIN6+,
RIN7+, RIN8+
Non-inverting LVDS Input
RIN1, RIN2,
RIN3, RIN4,
RIN5, RIN6,
RIN7, RIN8
Inverting LVDS Input
DOUT1+, DOUT2+,
DOUT3+, DOUT4+,
DOUT5+, DOUT6+,
DOUT7+, DOUT8+
Non-inverting Driver Output
DOUT1, DOUT2,
DOUT3, DOUT4,
DOUT5, DOUT6,
DOUT7, DOUT8
Inverting Driver Output
EN Driver Enable Pin for All Output
EN12 Inverting Driver Enable Pin for
DOUT1 and DOUT2
EN34 Inverting Driver Enable Pin for
DOUT3 and DOUT4
EN56 Inverting Driver Enable Pin for
DOUT5 and DOUT6
EN78 Inverting Driver Enable Pin for
DOUT7 and DOUT8
VCC Power Supply
GND Ground
VBB Refere nce Voltage Output
Inputs Outputs
EN ENxx DIN+DINDOUT+DOUT
HL HLHL
HL LHLH
H L Fail Safe Case H L
XHXXZZ
LXXXZZ
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FIN1108 FIN1108T (Preliminary)
Applications
Signal Optim iza tion via Int erna l Terminat io n
For LVDS signaling in point-to-poin t applications, receivers
or repeaters with on-chip termination are preferable to
reduce the overshoot or undershoot due to the reflection
caused by stubs at receiver inputs. As a rule of thumb, usu-
ally the termination resist or for an LVDS receiver shoul d be
placed as close as possible to the receiver, especially for
high speed applications. If the distance between termina-
tion resist ors and recei vers is to o lon g, the in tercon necti on
will be seen as an un-terminated stub which can produce
reflection s resu lting in hi gher EM I. Inte rnal te rmin ation c an
effectively smooth out this ringing which can otherwise
jeopard ize the receiv er noise m argin. Thi s is impor tant for
reliable high-speed operation with tighter required signal
settling times. Below is a list of the ad vantages/disadvan-
tages of internal ter mina tion .
Internal termination is not suitable for all applications. In
order to set a proper VOD at the driver outputs, receivers
with on-chip termination resistors only work for point-to-
point applications since multi-drop applications would
requir e termination res istor for eac h receiver, reducing the
equivalent termination to RT/n. This wou l d redu c e t h e dr iv e r
output swing by n.
Advantages: Disadvantages:
1. Reduced device count resulting in reduced board space
and production cost. 1. Without special process treatment, on-chip termination can
experience greater temperature variation. This is usually
tolerable for low speed applications that have a sufficient
unit interval.
2. Reduced reflections caused by the stub length on the
receiver inputs, improving the signal integrity. 2. For applications with high common-mode noise, a center
tapped capacitor at the receiver side is desirable to filter
out the common-mode voltage noise of the input L VDS sig-
nal. This scheme works for an external termination scheme
with two (50 each for nominal 100 termination resistor)
half-value termination resistors connected in series and
center tapped to a capacitor to Ground. To implement this
scheme using internal termination resist ors, a center tap
pin would have to be used. This would increase the pack-
age size of the part.
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FIN1108 FIN1108T (Preliminary)
Absolute Maximum Ratings(Note 1) Recommended Operating
Conditions
Note 1: The Absolute Maximum Ratings: are those values beyond which
damage to the device may occur. The databook specifications should be
met, without exception, to ensure that the system design is reliable over its
power supply, temperature and output/input loading variables. Fairchild
does no t re c om m end operation of circuit s o ut s ide data book specif ic ation.
DC Electrical Characteristics
Note 2: All typic al values are at TA = 25°C and with VCC = 3.3 V.
Supply Voltag e (VCC)0.5V to +4.6V
LVDS DC Input Voltage (VIN)0.5V to +4.6V
LVDS DC Output Voltage (VOUT)0.5V to +4.6V
Driver Short Circuit Current (IOSD) Cont inuous 10 mA
Storage Temperature Range (TSTG)65°C to +150°C
Max Junction Temperature (TJ)150°C
Lead Temperature (TL)
(Soldering, 10 seconds) 260°C
ESD (Human Body Model) 7500V
ESD (Machine Model) 400V
Supply Voltag e (VCC) 3.0V to 3.6V
Magnitude of Differential
Vol tage ( |VID|) 100 mV to VCC
Common Mode Voltage
Range (VIC)(0V + |VID|/2) to (VCC |VID|/2)
Operating Temperature (TA)40°C to +85°C
Symbol Parameter Test Conditions Min Typ Max Units
(Note 2)
VTH Differential Input Threshold HIGH See Figure 1; VIC = +0.05V, + 1.2V, or VCC 0.05V 100 mV
VTL Differential Input Threshold LOW See Figure 1; VIC = +0.05V, + 1.2V, or VCC 0.0 5V 100 mV
VIH Input HIGH Voltage (EN or EN)2.0V
CC V
VIL Input LOW Voltage (EN or EN)GND0.8V
VOD Output Differential Voltage 250 330 450 mV
VOD VOD Magnitude Change from 25 mV
Differential LOW-to-HIGH RL = 100 , Driver Enabled,
VOS Offset Voltage See Figure 2 1.125 1.23 1.375 V
VOS Offset Magnitude Change from 25 mV
Differential LOW-to-HIGH
IOS Short Circuit Output Current DOUT+ = 0V and DOUT = 0V, 3.4 6mA
Driver Enabled
VOD = 0V, Driver Enabled ±3.4 ±6mA
IIN Input Current (EN, EN, DINx+, DINx)V
IN = 0V to VCC, Other Input = VCC or 0V ±20 µA
(for Differential Inputs)
IOFF Power Off Input or Output Current VCC = 0V, VIN or VOUT = 0V to 3.6V ±20 µA
ICCZ Disabled Power Supply Current Drivers Disabled 20 mA
ICC Power Supply Current Drivers Enabled, Any Valid Input Condition 80 mA
IOZ Disabled Output Leakage Current Driver Disabled, DOUT+ = 0V to 3.6V or ±20 µA
DOUT = 0V to 3.6V
VIC Common Mode Voltage Range VID/2 VCC (VID/2) V
CIN Input Capacitance Enable Input 3 pF
LVDS Input 3
COUT Output Capacitance 3pF
VBB Output Reference Voltage VCC = 3.3V, IBB = 0 to 275 µA 1.125 1.2 1.375 V
RTTerminating Resistance 100
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FIN1108 FIN1108T (Preliminary)
AC Electrical Characteristics
Over supply voltage and operating temperature ranges, unless otherwise specified
Note 3: All typical values are at TA = 25°C and wit h VCC = 3.3V.
Note 4: tSK(LH), tSK(HL) is the ske w betw ee n spe cified outpu ts of a s ingle de vic e whe n the ou tputs have ident ical lo ads an d are swi tch ing in th e sam e direc-
tion.
Note 5: tSK(PP) is the ma gnitude of t he differen c e in propa gation delay times between an y specified term inals of tw o devi c es s w it c hing in the same direction
(either LOW-to-HIGH or HIGH-to-LOW) when both devices operate with the same supply voltage, same temperature, and have identical test circuits.
Note 6: Passing criteria for maximum frequency is the output VOD > 250 mV and the duty cycle is better than 45% / 55% with all channels switching.
Note 7: Output loading is transmiss ion line environm ent only; CL is < 1 pF of stray test fixture capacitance.
FIGURE 1. Differ entia l Receiver Voltage Definitions
FIGURE 2. Differential Driver DC Test Circuit
Note A: All LVDS input pulses have freq uency = 10 MHz, tR
or tF < = 0.5 ns
Note B: CL includes all probe and jig capacitances
FIGURE 3. Differential Driver Propagation Delay
and Transition Time Test Circuit
Symbol Parameter Test Conditions Min Typ Max Units
(Note 3)
tPLHD Differential Output Propagation Delay 0.75 1.1 1.75 ns
LOW-to-HIGH
tPHLD Differential Output Propagation Delay 0.75 1.1 1.75 ns
HIGH-to-LOW RL = 100 , CL = 5 pF,
tTLHD Differential Output Rise Time (20% to 80%) VID = 200 mV to 450 mV, 0.29 0.4 0.58 ns
tTHLD Differential Output Fall Time (80% to 20%) VIC = VID/2 to VCC (VID/2), 0.29 0.4 0.58 ns
tSK(P) Pulse Skew |tPLH - tPHL| Duty Cycle = 50%, 0.02 0.2 ns
tSK(LH), Channel-to-Channel Skew See Figure 1 and Figure 1 0.02 0.15 ns
tSK(HL) (Note 4) 0.02
tSK(PP) Part-to-Part Skew (Note 5) 0.5 ns
fMAX Maximum Frequency (Note 6)(Note 7) 400 >630 MHz
tPZHD Differential Output Enable Time 35ns
from Z to HIGH
tPZLD Differential Output Enable Time 3.1 5 ns
from Z to LOW RL = 100 , CL = 5 pF,
tPHZD Differential Output Disable Time See Figure 2 and Figure 3 2.2 5 ns
from HIGH to Z
tPLZD Differential Output Disable Time 2.5 5 ns
from LOW to Z
tDJ LVDS Data Jitter, VID = 300 mV, PRBS = 223 - 1, 80 135 ps
Deterministic VIC = 1.2V at 800 Mbps
tRJ LVDS Clock Jitter, VID = 300 mV, 1.9 3.5 ps
Random (RMS) VIC = 1.2V at 400 MHz
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FIN1108 FIN1108T (Preliminary)
FIGURE 4. AC Waveform
Note A: All LVTTL input pulses have frequency = 10MHz, tR or tF < = 2 ns
Note B: CL includes all probe and jig capacitances
FIGURE 5. Differential Driver Enable and Disable Circuit
FIGURE 6. Enable and Disable AC Waveforms
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FIN1108 FIN1108T (Preliminar y) LVDS 8 Port High Speed Repeater
48-Lea d Th in S hri n k Small Ou tlin e Pack age (TSSOP ), JED EC MO-1 53, 6.1mm Wide
Package Number MTD48
Fairchild does not assume an y responsibility fo r use of any circuitry described, no circuit patent licenses are im plied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
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