frequency can be set using the frequency select pins and a
25MHz crystal for Ethernet frequencies, or a 26.5625MHz
crystal for a Fibre Channel. The low phase noise character-
istics of the ICS844246 make it an ideal clock for these
demanding applications.
F
EATURES
•
Six LVDS outputs
•
Crystal oscillator interface
•
Output frequency range: 53.125MHz to 333.3333MHz
•
Crystal input frequency range: 25MHz to 33.333MHz
•
RMS phase jitter at 125MHz, using a 25MHz crystal
(1.875MHz to 20MHz): 0.39ps (typical)
•
Full 3.3V or 3.3V core, 2.5V output supply mode
•
0°C to 70°C ambient operating temperature
•
Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
Function
IC
S
S
ELECT
F
UNCTION
T
ABLE
Inputs
FB_SEL
0
0
0
0
1
1
1
1
N_SEL1
0
0
1
1
0
0
1
1
N_SEL0
0
1
0
1
0
1
0
1
M Divide
20
20
20
20
24
24
24
24
N Divide
2
4
5
8
3
4
6
12
M/N
10
5
4
2.5
8
6
4
2
B
LOCK
D
IAGRAM
Q0
nQ0
PLL_BYPASS
Pullup
P
IN
A
SSIGNMENT
V
DDO
V
DDO
nQ2
Q2
nQ1
Q1
nQ0
Q0
PLL_BYPASS
V
DDA
V
DD
FB_SEL
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Q3
nQ3
Q4
nQ4
Q5
nQ5
N_SEL1
GND
GND
N_SEL0
XTAL_OUT
XTAL_IN
Q1
1
XTAL_IN
XTAL_OUT
nQ1
OSC
PLL
0
Output
Divider
Q2
nQ2
Q3
nQ3
Q4
nQ4
Q5
nQ5
Feedback
Divider
FB_SEL
N_SEL1
N_SEL0
Pulldown
Pullup
Pullup
ICS844246
24-Lead TSSOP, E-Pad
4.40mm x 7.8mm x 0.90mm
body package
G Package
Top View
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
™
LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER
1
ICS844246BG REV.C NOVEMBER 14, 2007
ICS844246
FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
PRELIMINARY
T
ABLE
1. P
IN
D
ESCRIPTIONS
Number
1, 2
3, 4
5, 6
7, 8
9
10
11
12
13,
14
15,
18
16, 17
19, 20
21, 22
23, 24
Nam e
V
DDO
nQ2, Q2
nQ1, Q1
nQ0, Q0
PLL_BYPASS
V
DDA
V
DD
FB_SEL
XTAL_IN,
XTAL_OUT
N_SEL0
N_SEL1
GND
nQ5, Q5
nQ4, Q4
nQ3, Q3
Power
Output
Output
Output
Input
Power
Power
Input
Input
Input
Pullup
Type
Description
Output supply pins.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
Selects between the PLL and cr ystal inputs as the input to the dividers.
When LOW, selects PLL. When HIGH, selects XTAL_IN, XTAL_OUT.
LVCMOS / LVTTL interface levels.
Analog supply pin.
Core supply pin.
Pulldown Feedback frequency select pin. LVCMOS/LVTTL interface levels.
Cr ystal oscillator interface. XTAL_IN is the input.
XTAL_OUT is the output.
Pullup
Output frequency select pin. LVCMOS/LVTTL interface levels.
Power supply ground.
Output
Output
Output
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
Differential output pair. LVDS interface levels.
NOTE:
Pullup
and
Pulldown
refer to internal input resistors. See Table 2, Pin Characteristics, for typical values.
T
ABLE
2. P
IN
C
HARACTERISTICS
Symbol
C
IN
R
PULLUP
R
PULLDOWN
Parameter
Input Capacitance
Input Pullup Resistor
Input Pulldown Resistor
Test Conditions
Minimum
Typical
4
51
51
Maximum
Units
pF
kΩ
kΩ
IDT
™
/ ICS
™
LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER
2
ICS844246BG REV.C NOVEMBER 14, 2007
ICS844246
FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
PRELIMINARY
C
RYSTAL
F
UNCTION
T
ABLE
Inputs
XTAL (MHz)
25
25
25
25
25
25
25
25
26.5625
26.5625
26.5625
26.5625
26.5625
30
30
30
30
31.25
31.25
31.25
31.25
33.3333
33.3333
33.3333
33.3333
FB_SEL
0
0
0
0
1
1
1
1
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
N_SEL1
0
0
1
1
0
0
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
N_SEL0
0
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
M
20
20
20
20
24
24
24
24
20
24
24
24
24
20
20
20
20
20
20
20
20
20
20
20
20
500
500
500
500
600
600
600
600
531.25
637.5
637.5
637.5
637.5
600
600
600
600
625
62 5
62 5
625
666.6667
666.6667
666.6667
666.6667
Function
VCO (MHz)
N
2
4
5
8
3
4
6
12
5
3
4
6
12
2
4
5
8
2
4
5
8
2
4
5
8
Output (MHz)
250
125
100
62.5
200
150
100
50
106.25
212.5
159.375
106.25
53.125
300
150
120
75
312.5
156.25
125
78.125
333.3333
166.6667
133.3333
83.3333
IDT
™
/ ICS
™
LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER
3
ICS844246BG REV.C NOVEMBER 14, 2007
ICS844246
FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
PRELIMINARY
A
BSOLUTE
M
AXIMUM
R
ATINGS
Supply Voltage, V
DD
Inputs, V
I
Outputs, I
O
Continuous Current
Surge Current
4.6V
-0.5V to V
DD
+ 0.5V
10mA
15mA
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 Characteristics
is not
implied. Exposure to absolute maximum rating conditions for ex-
tended periods may affect product reliability.
Package Thermal Impedance,
θ
JA
24 Lead TSSOP, EPad
32.1°C/W (0 mps)
Storage Temperature, T
STG
-65°C to 150°C
T
ABLE
4A. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
DD
= V
DDO
= 3.3V±5%, T
A
= 0°C
TO
70°C
Symbol
V
DD
V
DDA
V
DDO
I
DD
I
DDA
I
DDO
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
Test Conditions
Minimum
3.135
V
DD
– 0.06
3.135
Typical
3.3
3.3
3.3
120
6
135
Maximum
3.465
V
DD
3.465
Units
V
V
V
mA
mA
mA
T
ABLE
4B. P
OWER
S
UPPLY
DC C
HARACTERISTICS
,
V
DD
= 3.3V±5%, V
DDO
= 2.5V±5%, T
A
= 0°C
TO
70°C
Symbol
V
DD
V
DDA
V
DDO
I
DD
I
DDA
I
DDO
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
Test Conditions
Minimum
3.135
V
DD
– 0.06
2.375
Typical
3.3
3.3
2. 5
120
6
120
Maximum
3.465
V
DD
2.625
Units
V
V
V
mA
mA
mA
T
ABLE
4C. LVCMOS / LVTTL DC C
HARACTERISTICS
,
V
DD
= 3.3V±5%, V
DDO
= 3.3V±5%
Symbol
V
IH
V
IL
I
IH
Parameter
Input High Voltage
Input Low Voltage
Input High Current
FB_SEL
PLL_BYPASS,
N_SEL0, N_SEL1
FB_SEL
PLL_BYPASS,
N_SEL0, N_SEL1
V
DD
= V
IN
= 3.465V
V
DD
= V
IN
= 3.465V
V
DD
= 3.465V, V
IN
= 0V
V
DD
= 3.465V, V
IN
= 0V
Test Conditions
OR
2.5V±5%, T
A
= 0°C
TO
70°C
Minimum
2
-0.3
Typical
Maximum
V
DD
+ 0.3
0. 8
150
5
Units
V
V
µA
µA
µA
µA
-5
-150
I
IL
Input Low Current
IDT
™
/ ICS
™
LVDS FREQUENCY SYNTHESIZER W/FANOUT BUFFER
4
ICS844246BG REV.C NOVEMBER 14, 2007
ICS844246
FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER W/INTEGRATED FANOUT BUFFER
PRELIMINARY
T
ABLE
4D. LVDS DC C
HARACTERISTICS
,
V
DD
= V
DDO
= 3.3V±5% T
A
= 0°C
TO
70°C
Symbol
V
OD
Δ
V
OD
V
OS
Δ
V
OS
Parameter
Differential Output Voltage
V
OD
Magnitude Change
Offset Voltage
V
OS
Magnitude Change
Test Conditions
Minimum
Typical
387
40
1.29
50
Maximum
Units
mV
mV
V
mV
NOTE: Please refer to Parameter Measurement Information for output information.
T
ABLE
4E. LVDS DC C
HARACTERISTICS
,
V
DD
= 3.3V±5%, V
DDO
= 2.5V±5%, T
A
= 0°C
TO
70°C
Symbol
V
OD
Δ
V
OD
V
OS
Δ
V
OS
Parameter
Differential Output Voltage
V
OD
Magnitude Change
Offset Voltage
V
OS
Magnitude Change
Test Conditions
Minimum
Typical
379
40
1.24
50
Maximum
Units
mV
mV
V
mV
T
ABLE
5. C
RYSTAL
C
HARACTERISTICS
Parameter
Mode of Oscillation
Frequency
Equivalent Series Resistance (ESR)
Shunt Capacitance
Drive Level
NOTE: Characterized using an 18pf parallel resonant crystal.
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