DATASHEET
LOW SKEW 1 TO 4 CLOCK BUFFER
Description
The ICS651 is a low skew, single input to four output, clock
buffer. Part of IDT’s ClockBlocks
TM
family, this is a low
skew, small clock buffer.
IDT makes many non-PLL and PLL based low skew output
devices as well as Zero Delay Buffers to synchronize
clocks. Contact us for all of your clocking needs.
ICS651
Features
•
•
•
•
•
•
•
•
Low skew outputs (250 ps)
Packaged in 8-pin SOIC
RoHS 6 compliant package
Low power CMOS technology
Operating Voltages of 1.5 V to 2.5 V
Output Enable pin tri-states outputs
3.3 V tolerant input clock
Industrial or commercial temperature ranges
Block Diagram
Q0
Q1
ICLK
Q2
Q3
Output Enable
IDT®
LOW SKEW 1 TO 4 CLOCK BUFFER
1
ICS651
REV H 101111
ICS651
LOW SKEW 1 TO 4 CLOCK BUFFER
FAN OUT BUFFER
Pin Assignment
8
7
6
5
ICLK
Q1
Q2
Q3
1
2
3
4
OE
VDD
GND
Q4
Pin Descriptions
Pin
Pin
Number Name
1
2
3
4
5
6
7
8
ICLK
Q1
Q2
Q3
Q4
GND
VDD
OE
Pin
Type
Input
Output
Output
Output
Output
Power
Power
Input
Clock Output 1.
Clock Output 2.
Clock Output 3.
Clock Output 4.
Connect to ground.
Connect to +1.5 V or +2.5 V.
Pin Description
Clock Input. 3.3 V tolerant input.
Output Enable. Tri-states outputs when low. Connect to VDD for normal operation.
External Components
A minimum number of external components are required for proper operation. A decoupling capacitor of 0.01
μ
F
should be connected between VDD on pin 7 and GND on pin 6, as close to the device as possible. A 33
Ω
series
terminating resistor may be used on each clock output if the trace is longer than 1 inch.
To achieve the low output skew that the ICS651 is capable of, careful attention must be paid to board layout.
Essentially, all four outputs must have identical terminations, identical loads and identical trace geometries. If they
do not, the output skew will be degraded. For example, using a 30
Ω
series termination on one output (with 33
Ω
on
the others) will cause at least 15 ps of skew.
IDT®
LOW SKEW 1 TO 4 CLOCK BUFFER
2
ICS651
REV H 101111
ICS651
LOW SKEW 1 TO 4 CLOCK BUFFER
FAN OUT BUFFER
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS651. These ratings, which are
standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the device at these
or any other conditions above those indicated in the operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical
parameters are guaranteed only over the recommended operating temperature range.
Item
Supply Voltage, VDD
Output Enable and All Outputs
ICLK
Ambient Operating Temperature (industrial)
Ambient Operating Temperature (commercial)
Storage Temperature
Junction Temperature
Soldering Temperature
7V
Rating
-0.5 V to VDD+0.5 V
-0.5 V to 3.6 V (VDD > 0V)
-40 to +85
°
C
0 to +70
°
C
-65 to +150
°
C
125
°
C
260
°
C
Recommended Operation Conditions
Parameter
Ambient Operating Temperature (industrial)
Ambient Operating Temperature (commercial)
Power Supply Voltage (measured in respect to GND)
Min.
-40
0
+1.425
Typ.
Max.
+85
+70
+2.625
Units
°
C
°
C
V
IDT®
LOW SKEW 1 TO 4 CLOCK BUFFER
3
ICS651
REV H 101111
ICS651
LOW SKEW 1 TO 4 CLOCK BUFFER
FAN OUT BUFFER
DC Electrical Characteristics
VDD=1.5 V ±
5%
, Ambient temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Operating Voltage
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
Operating Supply Current
Nominal Output Impedance
Input Capacitance
Short Circuit Current
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
IDD
Z
O
C
IN
I
OS
Conditions
Note 1, ICLK, OE
Note 1, ICLK, OE
I
OH
= -6 mA
I
OL
= 6 mA
No load, 133 MHz
ICLK, OE pin
Min.
1.425
1.17
1.35
Typ.
Max.
1.575
3.6
0.63
0.45
Units
V
V
V
V
V
mA
Ω
25
20
5
±28
pF
mA
Notes: 1. Nominal switching threshold is VDD/2
VDD=1.8 V ±5%
, Ambient temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Operating Voltage
Input High Voltage, ICLK
Input Low Voltage, ICLK
Output High Voltage
Output Low Voltage
Operating Supply Current
Nominal Output Impedance
Input Capacitance
Short Circuit Current
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
IDD
Z
O
C
IN
I
OS
Conditions
Note 1, ICLK, OE
Note 1, ICLK, OE
I
OH
= -8 mA
I
OL
= 8mA
No load, 133 MHz
ICLK, OE pin
Min.
1.71
1.17
1.35
Typ.
1.8
Max.
1.89
3.6
0.63
0.45
Units
V
V
V
V
V
mA
Ω
30
20
5
±32
pF
mA
Notes: 1. Nominal switching threshold is VDD/2
VDD=2.5 V ±5%
, Ambient temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Operating Voltage
Input High Voltage, ICLK
Input Low Voltage, ICLK
Output High Voltage
Output Low Voltage
Operating Supply Current
Nominal Output Impedance
Input Capacitance
Short Circuit Current
Symbol
VDD
V
IH
V
IL
V
OH
V
OL
IDD
Z
O
C
IN
I
OS
Conditions
Note 1, ICLK, OE
Note 1, ICLK, OE
I
OH
= -8 mA
I
OL
= 8mA
No load, 133 MHz
ICLK, OE pin
Min.
2.375
1.7
2
Typ.
Max.
2.625
3.6
0.7
0.4
Units
V
V
V
V
V
mA
Ω
50
20
5
±50
pF
mA
Notes: 1. Nominal switching threshold is VDD/2
IDT®
LOW SKEW 1 TO 4 CLOCK BUFFER
4
ICS651
REV H 101111
ICS651
LOW SKEW 1 TO 4 CLOCK BUFFER
FAN OUT BUFFER
AC Electrical Characteristics
VDD = 1.5 V ±5%
, Ambient Temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Input Frequency
Output Rise Time
Output Fall Time
Propagation Delay
Output to Output Skew
Symbol
t
OR
t
OF
Note 1
Note 2
Conditions
0.63 V to 1.17 V
1.17 V to 0.63 V
Min.
0
Typ.
1.0
1.0
Max. Units
166
1.5
1.5
5
±250
MHz
ns
ns
ns
ps
2.2
Rising edges at VDD/2
3
VDD = 1.8 V ±5%
, Ambient Temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Input Frequency
Output Rise Time
Output Fall Time
Propagation Delay
Output to Output Skew
Symbol
t
OR
t
OF
Note 1
Note 2
Conditions
0.63 V to 1.17 V
1.17 V to 0.63 V
Min.
0
Typ.
1.0
1.0
Max. Units
200
1.5
1.5
5
±250
MHz
ns
ns
ns
ps
2.2
Rising edges at VDD/2
3
VDD = 2.5 V ±5%
, Ambient Temperature -40 to +85
°
C or 0 to +70
°
C, unless stated otherwise
Parameter
Input Frequency
Output Rise Time
Output Fall Time
Propagation Delay
Output to Output Skew
Symbol
t
OR
t
OF
Note 1
Note 2
Conditions
0.7 V to 1.7 V
1.7 V to 0.7 V
Min.
0
Typ.
1.0
1.0
Max. Units
200
1.5
1.5
5
±250
MHz
ns
ns
ns
ps
2.2
Rising edges at VDD/2
3
Notes: 1. With rail to rail input clock
2. Between any 2 outputs with equal loading.
Thermal Characteristics
Parameter
Thermal Resistance Junction to
Ambient
Symbol
θ
JA
θ
JA
θ
JA
θ
JC
Ψ
JT
Conditions
Still air
1 m/s air flow
3 m/s air flow
Min.
Typ.
150
140
120
40
Max. Units
°
C/W
°
C/W
°
C/W
°
C/W
Thermal Resistance Junction to Case
Case Temperature
Thermal Resistance Junction to Top
of Case
120
Still air
20
°
C
°
C/W
IDT®
LOW SKEW 1 TO 4 CLOCK BUFFER
5
ICS651
REV H 101111
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