DATASHEET
ETHERNET SWITCH CLOCK SOURCE
Description
The ICS650-40A is a clock chip designed for use as a core
clock in Ethernet Switch applications. Using IDT’s patented
Phase-Locked Loop (PLL) techniques, the device takes a
25 MHz crystal input and produces various output clock
frequencies as listed in Output Select Table.
ICS650-40A
Features
•
•
•
•
•
•
Packaged in 16-pin TSSOP
Operating voltage of 3.3 V
Low power consumption
Input frequency of 25 MHz
Low long-term jitter
Separate supply voltage for clock outputs (2.5 / 3.3 V
clock outputs)
•
OE control capability
NOTE: EOL for non-green parts to occur on
5/13/10 per PDN U-09-01
Block Diagram
VDD
2
VDDOA
VDDOB
S1:S0
2
Control
Logic
CLKB
Phase Lock Loop
CLKA
CLKA
X1/ICLK
25 MHz
crystal or clock X2
Clock
Buffer/
Crystal
Oscillator
4
GND
Optional tuning crystal
capacitors
OE
IDT™ / ICS™
ETHERNET SWITCH CLOCK SOURCE
1
ICS650-40A
REV D 102709
ICS650-40A
ETHERNET SWITCH CLOCK SOURCE
CLOCK SYNTHESIZER
Pin Assignment
X1/ICLK
VDD
GNDA
VDDOA
CLKA
CLKA
GNDA
S1
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
X2
VDD
OE
GND
VDDOB
CLKB
GNDB
S0
Output Select Table (MHz)
S1
0
0
1
1
S0
0
1
0
1
CLKA
(MHz)
127
133
157
189
CLKA
(MHz)
127
133
157
189
CLKB
(MHz)
157
189
127
133
16-pin (173 mil) TSSOP
Pin Descriptions
Pin
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Pin
Name
X1/ICLK
VDD
GNDA
VDDOA
CLKA
CLKA
GNDA
S1
S0
GNDB
CLKB
VDDOB
GND
OE
Pin
Type
Input
Power
Power
Power
Output
Output
Power
Input
Input
Power
Output
Power
Power
Input
Connect to +3.3 V.
Connect to ground.
Pin Description
Crystal or clock input. Connect to a 25 MHz crystal or single ended clock.
Connect to +2.5 V or +3.3 V. For CLKA outputs only.
Clock A output with weak pull-down resistor.
Clock A output with weak pull-down resistor.
Connect to ground.
Select pin 1.
Select pin 0.
Connect to ground.
Clock B output with weak pull-down resistor.
Connect to +2.5 V or 3.3 V. For clock output B only.
Connect to ground.
Output enable tri-states outputs and device is not shut down. This input
has internal pull-up resistor. OE = 1 enables outputs A and B and OE=0
disables outputs A and B. When disabled the pull-down resistor pulls the
outputs to GND.
Connect to +3.3 V.
Crystal connection. Leave unconnected for clock input.
15
16
VDD
X2
Power
Output
IDT™ / ICS™
ETHERNET SWITCH CLOCK SOURCE
2
ICS650-40A
REV D 102709
ICS650-40A
ETHERNET SWITCH CLOCK SOURCE
CLOCK SYNTHESIZER
External Components
A minimum number of external components are required for proper operation. Decoupling capacitors of 0.01
µF
should be connected between VDD and GND pairs. The capacitors should be placed between pins VDD and GND,
VDDOA and GND, and VDDOB and GND as close to the device as possible. A 33Ω series terminating resistor
should be used on each clock output if the trace is longer than 1 inch. A 25 MHz fundamental mode parallel
resonant crystal should be used with C
L
=18 pF.
On chip capacitors.
On Chip capacitors are used for a 18 pF load crystal. Small, 2-3 pF trimming capacitors are
used from pins X1 to ground and X2 to ground to optimize the initial accuracy.
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS650-40A. 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
All Inputs and Outputs
Ambient Operating Temperature
Storage Temperature
Junction Temperature
Soldering Temperature
7V
Rating
-0.5 V to VDD+0.5 V
0 to +70° C
-65 to +150° C
125° C
260° C
Recommended Operation Conditions
Parameter
Ambient Operating Temperature
Power Supply Voltage (measured in respect to GND)
Min.
0
+3.15
Typ.
Max.
+70
+3.45
Units
°
C
V
IDT™ / ICS™
ETHERNET SWITCH CLOCK SOURCE
3
ICS650-40A
REV D 102709
ICS650-40A
ETHERNET SWITCH CLOCK SOURCE
CLOCK SYNTHESIZER
DC Electrical Characteristics
VDD=3.3 V ±5%, VDDOA = VDDOB= 3.3 V ±5%
Ambient Temperature 0 to +70° C
Parameter
Operating Voltage
Output Operating Voltage
Input High Voltage, ICLK
Input Low Voltage, ICLK
Input High Voltage, S1:S0:OE
Input Low Voltage, S1:S0:OE
Output High Voltage
Output Low Voltage
Operating Supply Current
IDD at Output Disable
Condition(OE low)
Short Circuit Current
Internal Pull-up Resistor
Internal Pull-down Resistor
Symbol
VDD
VDDOA,
B
V
IH
V
IL
V
IH
V
IL
V
OH
V
OL
IDD
Conditions
Min.
3.15
2.375
Typ.
Max.
3.45
3.45
Units
V
V
V
Note 1
Note 1
VDD/2+0.5
VDD/2-0.5
2
VDD
0.8
V
V
V
V
I
OH
= -12 mA,
3.3 V VDDO
I
OL
= 12 mA, 3.3
V VDDO
No load
No load
2.0
0.4
40
16
±70
300
300
V
mA
mA
mA
kΩ
kΩ
I
OS
R
PU
R
PD
Each output
OE pin
CLK outputs
Note: 1. Nominal switching threshold is VDD/2.
AC Electrical Characteristics
VDD=3.3 V ±5%, VDDOA = VDDOB = 3.3 V ±5%, C
L
=10 pF
Ambient Temperature 0 to +70° C
Parameter
Input Frequency
Output Rise Time
Output Fall Time
Output Clock Duty Cycle
Frequency Error
Output to Output Skew
between clocks of the same
frequency
Absolute Jitter, Short-term
P-P
Absolute Jitter, Short-term
C-C
Long-term Jitter
Symbol
t
OR
t
OF
Conditions
20% to 80% of VDD
80% to 20% of VDD
At VDD/2
All clocks
Min.
Typ.
25
0.6
0.6
Max. Units
MHz
ns
ns
60
250
%
ppm
ps
40
49-51
0
Variation from mean
Variation from mean
1000 clock cycles
±120
±120
600
ps
ps
ps
IDT™ / ICS™
ETHERNET SWITCH CLOCK SOURCE
4
ICS650-40A
REV D 102709
ICS650-40A
ETHERNET SWITCH CLOCK SOURCE
CLOCK SYNTHESIZER
Thermal Characteristics
Parameter
Thermal Resistance Junction to
Ambient
Symbol
θ
JA
θ
JA
θ
JA
θ
JC
Conditions
Still air
1 m/s air flow
3 m/s air flow
Min.
Typ.
78
70
68
37
Max. Units
°
C/W
°
C/W
°
C/W
°
C/W
Thermal Resistance Junction to Case
Marking Diagram
16
9
Marking Diagram (RoHS compliant)
16
9
650G-40A
######
YYWW$$
1
Notes:
1. ###### is the lot code.
650G40AL
######
YYWW
8
1
8
2. YYWW is the last two digits of the year, and the week number that the part was assembled.
3. “L” designates RoHS compliant package.
4. Bottom marking: country of origin if not USA.
IDT™ / ICS™
ETHERNET SWITCH CLOCK SOURCE
5
ICS650-40A
REV D 102709
京公网安备 11010802033920号
EEWORLD
