SM802124
ClockWorks™ DUAL 125MHz
Ultra-Low Jitter, CMOS
Frequency Synthesizer
General Description
The SM802124 is a member of the ClockWorks™ family of
devices from Micrel and provides an extremely low-noise
timing solution for Ethernet clock signals. It is based upon
a unique patented RotaryWave
®
architecture that provides
very-low phase noise.
The device operates from a 3.3V or 2.5V power supply
and synthesizes two CMOS output clocks at 125MHz from
a 15MHz LVCMOS reference clock.
Data sheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com
.
HU
UH
Features
•
Generates two LVCMOS clock outputs at 125MHz
•
2.5V or 3.3V operating range
•
Typical rms phase jitter @ 125MHz
1.875MHz to 20MHz : 85fs
(Input source dependent)
•
Industrial temperature range (–40°C to +85°C)
•
Green, RoHS, and PFOS compliant
•
Available in 24-pin 4mm
×
4mm QFN package
Applications
•
Gigabit Ethernet
Block Diagram
ClockWorks is a trademark of Micrel, Inc
RotaryWave is a registered trademark of Multigig, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
September 2011
M9999-101311-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SM802124
Ordering Information
(1)
Part Number
SM802124UMG
SM802124UMGTR
Note:
1. Devices are Green, RoHS, and PFOS compliant.
Marking
802124
802124
Shipping
Tube
Tape and Reel
Temperature Range
–40°C to +85°C
–40°C to +85°C
Package
24-Pin QFN
24-Pin QFN
Pin Configuration
24-Pin QFN (code)
(Top View)
September 2011
M9999-101311-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SM802124
Pin Description
Pin Number
17
21
3, 4, 16 , 20,
23, 24
1, 18
2, 22
Pin Name
Q0
Q1
NC
VDDO
VSSO
Pin Type
O
O
-
PWR
PWR
Pin Level
CMOS
CMOS
-
Pin Function
125MHz Clock Output
180 deg,125MHz Clock Output
No Connection. Do not connect anything to these pins.
Power Supply for Output
Power Supply Ground for Output
PLL Bypass, Selects Output Source
5
PLL_BYPASS
I, (SE)
LVCMOS
0 = Normal PLL Operation
1 = Output from Input Reference Clock
45KΩ pull-down
7, 10, 11, 12,
15, 19
8
6, 13 , 14
9
TEST
VDD
VSS
REF_IN
PWR
PWR
I, (SE)
LVCMOS
Factory Test pins, Do not connect anything to these pins.
Core Power Supply
Core Power Supply Ground
Reference Clock Input
September 2011
M9999-101311-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SM802124
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
, V
DDO
)......................................... +4.6V
Input Voltage (V
IN
)...............................−0.50V to V
DD
+ 0.5V
Lead Temperature (soldering, 20s) ........................... 260°C
Case Temperature..................................................... 115°C
Storage Temperature (T
s
).........................
−65°C
to
+150°C
Operating Ratings
(2)
Supply Voltage (V
DD
, V
DDO
)...................+2.375V to +3.465V
Ambient Temperature (T
A
).......................... –40°C to +85°C
Junction Thermal Resistance
(3)
QFN (θ
JA
)
Still-Air ........................................................ 50°C/W
QFN (ψ
JB
)
Junction-to-Board ....................................... 30°C/W
DC Electrical Characteristics
(4)
V
DD
= V
DDO
= 3.3V
±5%
or 2.5V
±5%
V
DD
= 3.3V
±5%,
V
DDO
= 2.5V
±5%
T
A
=
−40°C
to
+85°C.
Symbol
V
DD
, V
DDO
V
DD
, V
DDO
I
DD
Parameter
2.5V Operating Voltage
3.3V Operating Voltage
Supply current V
DD
+ V
DDO
Outputs open
Condition
Min.
2.375
3.135
Typ.
2.5
3.3
70
Max.
2.625
3.465
90
Units
V
V
mA
LVCMOS OUTPUT DC Electrical Characteristics
(4)
V
DD
= V
DDO
= 3.3V
±5%
or 2.5V
±5%
V
DD
= 3.3V
±5%,
V
DDO
= 2.5V
±5%
T
A
=
−40°C
to
+85°C.
R
L
= 50Ω to V
DDO
/2.
Symbol
Parameter
Condition
Min
V
DD
-0.7
0.6
Typ
Max
Units
V
V
V
OH
V
OL
Output High Voltage
Output Low Voltage
Fig. 4
Fig. 4
LVCMOS (PLL_BYPASS) DC Electrical Characteristics
(4)
V
DD
= 3.3V
±5%,
or 2.5V
±5%,
T
A
=
−40°C
to
+85°C.
Symbol
V
IH
V
IL
I
IH
I
IL
Parameter
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
V
DD
= V
IN
= 3.465V
V
DD
= 3.465V, V
IN
= 0V
−5
Condition
Min.
2
−0.3
Typ.
Max.
V
DD
+ 0.3
0.8
150
Units
V
V
μA
μA
REF_IN DC Electrical Characteristics
(4)
V
DD
= 3.3V
±5%,
or 2.5V
±5%,
T
A
=
−40°C
to
+85°C.
Symbol
V
IH
V
IL
I
IN
Parameter
Input High Voltage
Input Low Voltage
Input Current
V
IN
= 0V to V
DD
Condition
Min.
1.1
−0.3
−5
Typ.
Max.
V
DD
+ 0.3
0.6
5
Units
V
V
μA
September 2011
4
M9999-101311-B
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SM802124
AC Electrical Characteristics
(4, 5)
V
DD
= V
DDO
= 3.3V±5% or 2.5V±5%
V
DD
= 3.3V±5%, V
DDO
= 2.5V±5%
T
A
=
40°C to
85°C. R
L
= 50Ω to V
DDO
/2
Symbol
F
OUT
F
REF
T
R
/T
F
ODC
T
LOCK
T
jit
(∅)
Parameter
Output Frequency
Reference Input Frequency
LVCMOS Output Rise/Fall Time
Output Duty Cycle
PLL Lock Time
RMS Phase Jitter
(6)
Condition
Min.
Typ.
125
15
Max.
Units
MHz
MHz
20% – 80%
100
45
300
50
500
55
20
ps
%
ms
fs
Integration Range (1.875MHz – 20MHz)
Integration Range (12kHz – 20MHz)
5MHz
10MHz
20MHz
25MHz
85
320
-73
-82
-89
-96
Spurious Noise Components
dBc
Notes:
1.
Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not
implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.
Package thermal resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB.
The circuit is designed to meet the AC and DC specifications shown in the above table after thermal equilibrium has been established.
All phase-noise measurements were taken with an Agilent 5052B phase-noise system.
Ref_IN driven with a low-noise source ClockWorks SM802001 programmed for a 15MHz CMOS output. Phase noise will track the input phase noise
up to about 1MHz offset frequency.
2.
3.
4.
5.
6.
September 2011
5
M9999-101311-B
hbwhelp@micrel.com
or (408) 955-1690
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