SM840004-11KATR [MICREL]
62.5/125MHz Gigabit Ethernet, 4 Output, Ultra-Low Jitter Clock Synthesizer; 62.5 / 125MHz的千兆以太网,4个输出,超低抖动时钟合成器型号: | SM840004-11KATR |
厂家: | MICREL SEMICONDUCTOR |
描述: | 62.5/125MHz Gigabit Ethernet, 4 Output, Ultra-Low Jitter Clock Synthesizer |
文件: | 总10页 (文件大小:231K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
SM840004-11
62.5/125MHz Gigabit Ethernet, 4 Output,
Ultra-Low Jitter Clock Synthesizer
General Description
Features
The SM840004-11 clock synthesizer was designed for
Gigabit Ethernet applications. The device design is
optimized for 62.5MHz and 125MHz using a standard
25MHz fundamental parallel resonant crystal, with
unparalleled stability and accuracy over the full operating
range, and provides an easy fit for Jitter and Phase Noise
standards for these high performance interfaces.
• Generates 4 optimized LVCMOS clock outputs
• RMS phase jitter @ 125MHz: ~55 fs (typ)
• Integrated loop filter components
• Operates with either a 3.3V or 2.5V supply
• Power consumption 65mA (typ @ 2.5V)
• Selectable output frequency: 125MHz or 62.5MHz
• Input frequency of 25MHz
• Fundamental parallel resonant crystal interface
• Pin compatible with the ICS/IDT840004-11
• Industrial temperature range: –40°C to +85°C
• Green, RoHS-compliant and PFOS-compliant
The SM840004-11 design includes a unique power
reduction methodology, along with
a
patented
RotaryWave™ architecture, that provides a stable clock
with very low noise for optimized performance. This yields
an overall improved Bit Error Rate (BER) and improved
waveform integrity.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
___________________________________________________________________________________________________________
Block Diagram
RotaryWave is a 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
M9999-070110-A
hbwhelp@micrel.com or (408) 955-1690
July 2010
Micrel, Inc.
SM840004-11
Ordering Information(1)
Part Number
Package
Type
Operating
Range
Package Marking
SM840004-11KA
SM840004-11KA TR
Note:
K-20
K-20
Industrial
Industrial
840004-11
840004-11
1. Devices are Green, RoHS-compliant and PFOS-compliant.
Pin Configuration
20-Pin TSSOP (K-20)
Pin Description
Pin Number
Pin Name
F_SEL
NC
Type
Level
Pull-up
NC
Pin Function
1
I
Frequency Select Pin.
No Connect. Do Not Use.
Output Enable: (1=Active, 0=High-Z)
Analog Power.
2,3,4,6,7,9,20
5
8
OE
I
Pull-up
VDDA
P
P
O
I
10
VDD
Core Power.
11
XTAL_OUT
XTAL_IN
GND
Q3
Crystal Out.
12
Crystal In.
13,19
14
P
O
O
P
O
O
Ground.
Single Ended LVCMOS Clock Out-3.
Single Ended LVCMOS Clock Out-2.
Output Power Supply.
Single Ended LVCMOS Clock Out-1.
Single Ended LVCMOS Clock Out-0.
15
Q2
16
VDDO
17
Q1
18
Q0
Configuration Table
F_SEL
M/N Ratio
M Divider
130
N Divider
Output Frequency (MHz)
0
1
2.5
5
52
26
62.5
125
130
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Micrel, Inc.
SM840004-11
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VDD)...................................................+4.6V
Input Voltage (VIN)................................ –0.50V to VDD+0.5V
Output Voltage (VOUT) .......................... –0.50V to VDD+0.5V
Lead Temperature (soldering, 20sec.)....................... 260°C
Storage Temperature (Ts) .........................–65°C to +150°C
Supply Voltage (VIN)............................. +2.375V to +3.465V
Ambient Temperature (TA) ..........................–40°C to +85°C
Junction Thermal Resistance
TSSOP (θJA).....................................................113°C/W
DC Electrical Characteristics
VDD = 2.5V ±5%; TA = –40°C to +85°C, unless noted.
Symbol
VDD
Parameter
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
Condition
Min
Typ
2.50
2.50
2.50
0.1
Max
2.625
2.625
2.625
1
Units
V
2.375
2.375
2.375
VDDA
VDDO
IDD
V
V
mA
mA
mA
IDDA
50
60
IDD0
No Load
15
23
DC Electrical Characteristics
VDD = 3.3V ±5%; TA = –40°C to +85°C, unless noted.
Symbol
Parameter
Condition
Min
Typ
3.30
3.30
3.30
0.1
Max
3.465
3.465
3.465
1
Units
V
VDD
Core Supply Voltage
Analog Supply Voltage
Output Supply Voltage
Power Supply Current
Analog Supply Current
Output Supply Current
3.135
3.135
3.135
VDDA
VDDO
IDD
V
V
mA
mA
mA
IDDA
50
60
IDDO
No Load
25
32
LVCMOS DC Electrical Characteristics
TA = –40°C to +85°C, unless noted.
Symbol
Parameter
Condition
VDD = 3.3V ±5%
DD = 2.5V ±5%
VDD = 3.3V ±5%
DD = 2.5V ±5%
VDD = 3.3V ±5%
DD = 2.5V ±5%
Min
2
Typ
Max
VDD +0.3
VDD + 0.3
0.80
Units
V
VIH
Input HIGH Voltage
V
1.7
V
-0.30
-0.30
2.6
V
VIL
Input LOW Voltage
V
0.70
V
V
VOH
Output HIGH Voltage
V
1.8
V
VOL
IIH
Output LOW Voltage
Input HIGH Current
Input LOW Current
Input HIGH Current
Input LOW Current
0.5
5
V
Output Enable input
Output Enable input
FSEL input
µA
µA
µA
µA
IIL
-150
-5
IIH
150
IIL
FSEL input
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
M9999-070110-A
hbwhelp@micrel.com or (408) 955-1690
July 2010
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Micrel, Inc.
SM840004-11
AC Electrical Characteristics
VDD = 2.5V and 3.3V ±5%; TA = –40°C to +85°C, unless noted.
Symbol
Parameter
Condition
F_SEL = 1
F_SEL = 0
Min
Typ
125
62.5
Max
Units
FOUT
Output Frequency
Output to Output Skew
RMS Phase Jitter(random)
MHz
tSKEW
12
52
ps
fs
125MHz @ 1.875MHz-20MHz
62.5MHz @ 1.875MHz-20MHz
20% to 80%
55
356
300
50
tJITTER
fs
tR / tF
ODC
Output Rise/Fall Time
Output Duty Cycle
ps
%
62.5MHz & 125MHz
48
Test Circuit
3.3V Output Load AC Test Circuit
3.3V Carrier Frequency, 62.5MHz
3.3V Carrier Frequency, 125MHz
Offset from Carrier
100Hz
Measured Phase Noise
Unit
Offset from Carrier
100Hz
Measured Phase Noise
Unit
-103
-124
-137
-135
-145
-151
-169
-169
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
-103
-125
-134
-132
-143
-152
-166
-167
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
1kHz
1kHz
10kHz
10kHz
100kHz
100kHz
1MHz
1MHz
1.825MHz
10MHz
1.825
10MHz
20MHz
20MHz
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SM840004-11
Crystal Characteristics
Parameter
Min
Typ
Max
Units
Mode of Oscillation
Frequency
Fundamental Parallel Resonant
25
50
7
MHz
Ω
Equivalent Series Resistance (ESR)
Shunt Capacitor
Drive Level
pF
1
mW
Functional Description
The SM840004-11 provides a high performance and
high accuracy solution for a precision clock source at
either 62.5MHz or 125MHz derived from a low cost
25MHz Xtal. Four synchronous low skew 12mA capable
LVCMOS outputs are provided with tri state controlled
via an external pin (OE).
integer divide ratios. Output divider ratios are fixed at
either ÷26 or ÷52 via the F_SEL pin, and the feedback
divider is fixed at ÷130. Duty Cycle is inherently
improved and provides tight control and stability on this
critical
specification.
This
provides
improved
specifications for Duty Cycle, Jitter, Phase Noise, Power
Consumption, and noise sensitivity. Additionally, the
SM840004-11 will operate at either 3.3V or 2.5V
supplies.
The design of the SM840004-11 consumes very low
power in the PLL due to a patented technology in the
VCO and the associated dividers. The VCO range is
~3.2GHz to 3.5GHz providing high resolution and easy
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July 2010
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Micrel, Inc.
SM840004-11
RMS Phase Noise/Jitter
Phase Noise Plot 125MHz @ 3.3V
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July 2010
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SM840004-11
Switching Waveforms
Output Rise/Fall Time
Output-Output Skew
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Micrel, Inc.
SM840004-11
Power Supply Filtering
Crystal Loading
The SM840004-11 provides separate power supply pins to
isolate any high switching noise from outputs to internal
core blocks. VDD and VDDA should be individually
connected to the power plane through vias. Bypass
capacitors should be used for each pin. Figure 2,
illustrates how the power supply filter for 3.3V and 2.5V is
configured.
Crystal Recommendations
This device requires
a
parallel resonance crystal.
Substituting a series resonance crystal will cause this
device to operate at the wrong frequency and violate the
ppm specifications.
To achieve low ppm error, the total capacitance the crystal
will see must be considered to calculate the appropriate
capacitive loading (CL).
Load Capacitance at each side: Trim Capacitance = Ct =
(2*CL-(Cb + Cd))
CL: Crystal load capacitance. Defined by manufacturer
Ct: External trim capacitors. (Trimmed CL Load
capacitance to get the right ppm)
Cb: Board capacitance (vias, traces, etc.)
Cd: Internal capacitance of the device (lead frame, bond
wires, pin, etc.)
Equivalent Series
Resistance (ESR)
Max.
Cut
Load
Cap.
Shunt
Cap.
Max.
Drive
Max.
Figure 2. Power Supply Filter
50Ω
AT
18pF
7pF
0.1mW
Crystal Input Interface
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July 2010
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Micrel, Inc.
SM840004-11
Total capacitance seen by crystal = CL =
1
Example:
CL = 18pF, Cb = 2pF, Cd = 4pF
Trim Cap = Ct = 2 (18pF) - (2pF +4pF) = 30pF
The SM840004-11has been characterized with 19.44MHz,
18pF parallel resonant crystal. The trim capacitors Ct1 and
Ct2 were optimized to minimize the ppm error.
1
+
1
(Ct1 + Cb1 + Cd1)
(Ct2 + Cb2 + Cd2)
To minimize the board capacitance, a short trace from pin
to crystal footprint without vias is desirable. It is preferable
to have ground shielding or distance between the crystal
traces and noisy signals on the board.
M9999-070110-A
hbwhelp@micrel.com or (408) 955-1690
July 2010
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Micrel, Inc.
SM840004-11
Package Information
20-Pin TSSOP (K-20)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2010 Micrel, Incorporated.
M9999-070110-A
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July 2010
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