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User's Guide

SNAA068B – July 2009 – Revised May 2013

AN-1966 LMH2190 Evaluation Board

1

General Description

The evaluation board (

Figure 1

) is designed to help the evaluation of the LMH2190 Quad Channel 26 MHz

Clock Tree Driver with I

2

C™ interface. The LMH2190 provides a digital system clock to peripheral devices

in mobile handsets. It provides a solution to clocking issues such as limited drive capability for fanout or
longer traces, protection of the master clock from varying loads and frequency pulling effects, isolation
buffering from noisy modules, and crosstalk isolation. It has very low phase noise which enables it to drive
sensitive modules such as Wireless LAN and Bluetooth.

Figure 1. LMH2190 Evaluation Board

I

2

C is a trademark of Philips Semiconductor Corp.

All other trademarks are the property of their respective owners.

1

SNAA068B – July 2009 – Revised May 2013

AN-1966 LMH2190 Evaluation Board

Submit Documentation Feedback

Copyright © 2009–2013, Texas Instruments Incorporated

Содержание AN-1966 LMH2190

Страница 1: ...e capability for fanout or longer traces protection of the master clock from varying loads and frequency pulling effects isolation buffering from noisy modules and crosstalk isolation It has very low phase noise which enables it to drive sensitive modules such as Wireless LAN and Bluetooth Figure 1 LMH2190 Evaluation Board I2 C is a trademark of Philips Semiconductor Corp All other trademarks are ...

Страница 2: ...er can drive 50 ohm making them excellent for connecting to measurement equipment like a Signal Source Analyzer This analyzer can for instance measure the Phase noise and Jitter The three buffers can be connected to the clock s by J7 J16 and J17 When the buffers are not used it is recommended to disconnect them since they increase the capacitive load on the clocks slightly 2 3 Clock Request The CL...

Страница 3: ...F from CLK2 to GND 5 6 Connects 33 pF from CLK2 to GND 7 8 Connects 47 pF from CLK2 to GND J3 ENABLE 1 2 ENABLE VOUT 3 4 ENABLE is supplied by CON7 5 6 ENABLE is supplied by I2 C conector J4 pin 4 7 8 ENABLE GND J4 I2 C Header Header to connect I2 C signals J5 CLK_REQx Logic High 1 2 CLK_REQxHIGH VOUT Level 3 4 CLK_REQxHIGH VBAT 5 6 CLK_REQxHIGH VENABLE 1 Bold face jumper settings refer to the fac...

Страница 4: ...n board TCXO J14 CLK3 Capacitive load 1 2 Connects 10 pF from CLK3 to GND 3 4 Connects 22 pF from CLK3 to GND 5 6 Connects 33 pF from CLK3 to GND 7 8 Connects 47 pF from CLK3 to GND J15 CLK4 Capacitive load 1 2 Connects 10 pF from CLK4 to GND 3 4 Connects 22 pF from CLK4 to GND 5 6 Connects 33 pF from CLK4 to GND 7 8 Connects 47 pF from CLK4 to GND J16 Connects Buffer to Open No buffer connected t...

Страница 5: ...plied unless buffers U2 U3 and or U4 are used for the measurements In factory default configuration only CLK1 is enabled With an oscilloscope and Hi impedance probes the TCXO J13 4 and CLK1 TP1 can be measured This should result in a measurement as depicted in Figure 4 Other CLK s can be enabled by connecting the appropriate CLK_REQ to VBAT J8 J10 J12 A schematic representation of the TCXO and all...

Страница 6: ...pF C3 C8 C20 C23 0603 Capacitor 33 pF C6 Case A Capacitor NC C7 C28 C31 Case A Capacitor 10 µF C9 C10 C25 C29 C30 0603 Capacitor 100 nF C12 C16 0603 Capacitor 10 nF C14 C15 0603 Capacitor 470 pF C17 C18 C21 C24 0603 Capacitor 47 pF C26 R9 R10 R13 R15 0603 Capacitor Resistor NC C27 Case A Capacitor 2 2 µF CON1 Connector SMA 6 AN 1966 LMH2190 Evaluation Board SNAA068B July 2009 Revised May 2013 Subm...

Страница 7: ...R21 R22 0603 Resistor 51Ω U1 DSBGA LMH2190 U2 U3 U4 SOIC LMH6559 X1 small TCXO 26 0MHz 7 Board Layout As with any other device careful attention must be paid to the board layout If the board is not properly designed the performance of the device can be less than might be expected Especially the input clock trace SCLK_IN and output traces CLK1 2 3 4 should be as short as possible to reduce the capa...

Страница 8: ...Layout www ti com Figure 7 Component Locations Top Side 8 AN 1966 LMH2190 Evaluation Board SNAA068B July 2009 Revised May 2013 Submit Documentation Feedback Copyright 2009 2013 Texas Instruments Incorporated ...

Страница 9: ...ard Layout Figure 8 Component Locations Bottom Side Bottom View 9 SNAA068B July 2009 Revised May 2013 AN 1966 LMH2190 Evaluation Board Submit Documentation Feedback Copyright 2009 2013 Texas Instruments Incorporated ...

Страница 10: ...luation Board Figure 10 Inner Layer of Evaluation Board Figure 11 Bottom Layer of Evaluation Board 10 AN 1966 LMH2190 Evaluation Board SNAA068B July 2009 Revised May 2013 Submit Documentation Feedback Copyright 2009 2013 Texas Instruments Incorporated ...

Страница 11: ...esponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related information or support that may be provided by TI Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failur...

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