SM840004-11KA [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：	SM840004-11KA
厂家：	MICREL SEMICONDUCTOR
描述：	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以太网时钟
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中文：	中文翻译
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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

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

Industrial

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

Type

Level

Pull-up

Pin Function

Frequency Select Pin.

No Connect. Do Not Use.

Output Enable: (1=Active, 0=High-Z)

Analog Power.

2,3,4,6,7,9,20

Pull-up

V_DDA

V_DD

Core Power.

XTAL_OUT

XTAL_IN

GND

Crystal Out.

Crystal In.

13,19

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.

V_DDO

Configuration Table

F_SEL

M/N Ratio

M Divider

130

N Divider

Output Frequency (MHz)

2.5

62.5

125

130

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

Micrel, Inc.

SM840004-11

Absolute Maximum Ratings⁽¹⁾

Operating Ratings⁽²⁾

Supply Voltage (V_DD)...................................................+4.6V

Input Voltage (V_IN)................................ –0.50V to V_DD+0.5V

Output Voltage (V_OUT) .......................... –0.50V to V_DD+0.5V

Lead Temperature (soldering, 20sec.)....................... 260°C

Storage Temperature (T_s) .........................–65°C to +150°C

Supply Voltage (V_IN)............................. +2.375V to +3.465V

Ambient Temperature (T_A) ..........................–40°C to +85°C

Junction Thermal Resistance

TSSOP (θ_JA).....................................................113°C/W

DC Electrical Characteristics

V_DD= 2.5V ±5%; T_A= –40°C to +85°C, unless noted.

Symbol

V_DD

Parameter

Core Supply Voltage

Analog Supply Voltage

Output Supply Voltage

Power Supply Current

Analog Supply Current

Output Supply Current

Condition

Min

Typ

2.50

0.1

Max

2.625

Units

2.375

V_DDA

V_DDO

I_DD

I_DDA

I_DD0

No Load

DC Electrical Characteristics

V_DD= 3.3V ±5%; T_A= –40°C to +85°C, unless noted.

Symbol

Parameter

Condition

Min

Typ

3.30

0.1

Max

3.465

Units

V_DD

Core Supply Voltage

Analog Supply Voltage

Output Supply Voltage

Power Supply Current

Analog Supply Current

Output Supply Current

3.135

V_DDA

VDDO

I_DD

I_DDA

I_DDO

No Load

LVCMOS DC Electrical Characteristics

T_A= –40°C to +85°C, unless noted.

Symbol

Parameter

Condition

V_DD= 3.3V ±5%

_DD= 2.5V ±5%

V_DD= 3.3V ±5%

_DD= 2.5V ±5%

V_DD= 3.3V ±5%

_DD= 2.5V ±5%

Min

Typ

Max

V_DD+0.3

V_DD+ 0.3

0.80

Units

V_IH

Input HIGH Voltage

1.7

-0.30

2.6

V_IL

Input LOW Voltage

0.70

V_OH

Output HIGH Voltage

1.8

V_OL

I_IH

Output LOW Voltage

Input HIGH Current

Input LOW Current

Input HIGH Current

Input LOW Current

0.5

Output Enable input

FSEL input

µA

I_IL

-150

-5

I_IH

150

I_IL

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

Micrel, Inc.

SM840004-11

AC Electrical Characteristics

V_DD= 2.5V and 3.3V ±5%; T_A= –40°C to +85°C, unless noted.

Symbol

Parameter

Condition

F_SEL = 1

F_SEL = 0

Min

Typ

125

62.5

Max

Units

F_OUT

Output Frequency

Output to Output Skew

RMS Phase Jitter(random)

MHz

t_SKEW

125MHz @ 1.875MHz-20MHz

62.5MHz @ 1.875MHz-20MHz

20% to 80%

356

300

t_JITTER

t_R/ t_F

ODC

Output Rise/Fall Time

Output Duty Cycle

62.5MHz & 125MHz

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

dBc/Hz

-103

-125

-134

-132

-143

-152

-166

-167

dBc/Hz

1kHz

10kHz

100kHz

1MHz

1.825MHz

10MHz

1.825

10MHz

20MHz

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

Micrel, Inc.

SM840004-11

Crystal Characteristics

Parameter

Min

Typ

Max

Units

Mode of Oscillation

Frequency

Fundamental Parallel Resonant

MHz

Ω

Equivalent Series Resistance (ESR)

Shunt Capacitor

Drive Level

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

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

Micrel, Inc.

SM840004-11

RMS Phase Noise/Jitter

Phase Noise Plot 125MHz @ 3.3V

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

Micrel, Inc.

SM840004-11

Switching Waveforms

Output Rise/Fall Time

Output-Output Skew

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

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

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

18pF

7pF

0.1mW

Crystal Input Interface

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

Micrel, Inc.

SM840004-11

Total capacitance seen by crystal = CL =

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.

(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

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.

M9999-070110-A

hbwhelp@micrel.com or (408) 955-1690

July 2010

SM840004-11KA [MICREL]

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