MICREL SM840004-11KA

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
• Generates 4 optimized LVCMOS clock outputs
Gigabit Ethernet applications. The device design is
• RMS phase jitter @ 125MHz: ~55 fs (typ)
optimized for 62.5MHz and 125MHz using a standard
• Integrated loop filter components
25MHz fundamental parallel resonant crystal, with
• Operates with either a 3.3V or 2.5V supply
unparalleled stability and accuracy over the full operating
• Power consumption 65mA (typ @ 2.5V)
range, and provides an easy fit for Jitter and Phase Noise
standards for these high performance interfaces.
• Selectable output frequency: 125MHz or 62.5MHz
The SM840004-11 design includes a unique power
• Input frequency of 25MHz
reduction methodology, along with a patented
• Fundamental parallel resonant crystal interface
RotaryWave™ architecture, that provides a stable clock
• Pin compatible with the ICS/IDT840004-11
with very low noise for optimized performance. This yields
• Industrial temperature range: –40°C to +85°C
an overall improved Bit Error Rate (BER) and improved
waveform integrity.
• Green, RoHS-compliant and PFOS-compliant
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
July 2010
M9999-070110-A
[email protected] or (408) 955-1690
Micrel, Inc.
SM840004-11
Ordering Information(1)
Package
Type
Operating
Range
Package Marking
SM840004-11KA
K-20
Industrial
840004-11
SM840004-11KA TR
K-20
Industrial
840004-11
Part Number
Note:
1. Devices are Green, RoHS-compliant and PFOS-compliant.
Pin Configuration
20-Pin TSSOP (K-20)
Pin Description
Pin Number
Pin Name
Type
Level
Pin Function
1
F_SEL
I
Pull-up
Frequency Select Pin.
2,3,4,6,7,9,20
NC
5
OE
I
NC
Pull-up
No Connect. Do Not Use.
Output Enable: (1=Active, 0=High-Z)
8
VDDA
P
Analog Power.
10
VDD
P
Core Power.
11
XTAL_OUT
O
Crystal Out.
12
XTAL_IN
I
Crystal In.
13,19
GND
P
Ground.
14
Q3
O
Single Ended LVCMOS Clock Out-3.
15
Q2
O
Single Ended LVCMOS Clock Out-2.
16
VDDO
P
Output Power Supply.
17
Q1
O
Single Ended LVCMOS Clock Out-1.
18
Q0
O
Single Ended LVCMOS Clock Out-0.
Configuration Table
F_SEL
M/N Ratio
M Divider
N Divider
Output Frequency (MHz)
0
2.5
130
52
62.5
1
5
130
26
125
July 2010
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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.
Min
Typ
Max
Units
VDD
Symbol
Core Supply Voltage
Parameter
Condition
2.375
2.50
2.625
V
VDDA
Analog Supply Voltage
2.375
2.50
2.625
V
VDDO
Output Supply Voltage
2.375
2.50
2.625
V
IDD
Power Supply Current
0.1
1
mA
IDDA
Analog Supply Current
50
60
mA
IDD0
Output Supply Current
15
23
mA
Min
Typ
Max
Units
No Load
DC Electrical Characteristics
VDD = 3.3V ±5%; TA = –40°C to +85°C, unless noted.
Symbol
Parameter
Condition
VDD
Core Supply Voltage
3.135
3.30
3.465
V
VDDA
Analog Supply Voltage
3.135
3.30
3.465
V
VDDO
Output Supply Voltage
3.135
3.30
3.465
V
IDD
Power Supply Current
0.1
1
mA
IDDA
Analog Supply Current
50
60
mA
IDDO
Output Supply Current
25
32
mA
No Load
LVCMOS DC Electrical Characteristics
TA = –40°C to +85°C, unless noted.
Symbol
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VOH
Output HIGH Voltage
Max
Units
VDD = 3.3V ±5%
Condition
2
VDD +0.3
V
VDD = 2.5V ±5%
1.7
VDD + 0.3
V
VDD = 3.3V ±5%
-0.30
0.80
V
VDD = 2.5V ±5%
-0.30
0.70
V
VDD = 3.3V ±5%
2.6
V
VDD = 2.5V ±5%
1.8
V
VOL
Output LOW Voltage
IIH
Input HIGH Current
Output Enable input
IIL
Input LOW Current
Output Enable input
IIH
Input HIGH Current
FSEL input
IIL
Input LOW Current
FSEL input
Min
Typ
0.5
V
5
µA
-150
µA
150
-5
µA
µA
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
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
Min
Typ
FOUT
Output Frequency
tSKEW
Output to Output Skew
tJITTER
RMS Phase Jitter(random)
62.5MHz @ 1.875MHz-20MHz
356
fs
t R / tF
Output Rise/Fall Time
20% to 80%
300
ps
ODC
Output Duty Cycle
62.5MHz & 125MHz
F_SEL = 1
125
F_SEL = 0
62.5
Max
MHz
12
125MHz @ 1.875MHz-20MHz
55
48
50
Units
ps
fs
52
%
Test Circuit
3.3V Output Load AC Test Circuit
3.3V Carrier Frequency, 62.5MHz
Offset from Carrier
Measured Phase Noise
3.3V Carrier Frequency, 125MHz
Unit
Offset from Carrier
Measured Phase Noise
Unit
100Hz
-103
dBc/Hz
100Hz
-103
dBc/Hz
1kHz
-124
dBc/Hz
1kHz
-125
dBc/Hz
10kHz
-137
dBc/Hz
10kHz
-134
dBc/Hz
100kHz
-135
dBc/Hz
100kHz
-132
dBc/Hz
1MHz
-145
dBc/Hz
1MHz
-143
dBc/Hz
1.825MHz
-151
dBc/Hz
1.825
-152
dBc/Hz
10MHz
-169
dBc/Hz
10MHz
-166
dBc/Hz
20MHz
-169
dBc/Hz
20MHz
-167
dBc/Hz
July 2010
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Micrel, Inc.
SM840004-11
Crystal Characteristics
Parameter
Min
Mode of Oscillation
Fundamental Parallel Resonant
Typ
Frequency
Max
25
Units
MHz
Equivalent Series Resistance (ESR)
50
Ω
Shunt Capacitor
7
pF
Drive Level
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).
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
July 2010
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.
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Micrel, Inc.
SM840004-11
RMS Phase Noise/Jitter
Phase Noise Plot 125MHz @ 3.3V
July 2010
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SM840004-11
Switching Waveforms
Output Rise/Fall Time
Output-Output Skew
July 2010
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SM840004-11
Power Supply Filtering
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 Loading
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.)
Figure 2. Power Supply Filter
Equivalent Series
Resistance (ESR)
Max.
Cut
Load
Cap.
Shunt
Cap.
Max.
Drive
Max.
50Ω
AT
18pF
7pF
0.1mW
Crystal Input Interface
July 2010
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Micrel, Inc.
SM840004-11
Total capacitance seen by crystal = CL =
1
1
(Ct1 + Cb1 + Cd1)
July 2010
+
1
(Ct2 + Cb2 + Cd2)
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.
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.
9
M9999-070110-A
[email protected] or (408) 955-1690
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.
July 2010
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M9999-070110-A
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