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User's Guide

SNOA535B–October 2008–Revised May 2013

AN-1906 LMH6518 Evaluation Board

1 Package Includes

• LMH6518 evaluation board (tested board that takes a 5 V and ground power supply connection and

outputs main and auxiliary differential outputs).

• USB Interface board (Figure 1) with 10 pin interconnect cable (to mate with J6 on LMH6518 evaluation

board). This board interfaces to a PC USB port to “Write” the SPI interface signals to the LMH6518

and can also display the LMH6518 state through “Read” back.

• USB Cable

Figure 1. USB Interface Board

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SNOA535B–October 2008–Revised May 2013 AN-1906 LMH6518 Evaluation Board

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Summary of content (6 pages)

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User's Guide SNOA535B – October 2008 – Revised May 2013 AN-1906 LMH6518 Evaluation Board 1 Package Includes • • • LMH6518 evaluation board (tested board that takes a 5 V and ground power supply connection and outputs main and auxiliary differential outputs). USB Interface board (Figure 1) with 10 pin interconnect cable (to mate with J6 on LMH6518 evaluation board).
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Additional Items Needed 2 www.ti.com Additional Items Needed • • PC (Windows) with web connection A single ended input signal for testing the LMH6518. The input signal should be of the speed, purity, and fidelity needed to test LMH6518 functionality and to not limit measured performance. The LMH6518 has differential input; however, this evaluation board is configured for single ended drive (into the positive input, “+IN” (J3) SMA connector) and the undriven input is biased to VCC/2 (= 2.5 V) on board.
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Setup and Operation www.ti.com 7. Plug the 10 pin female end of the ribbon cable from the USB Interface board into J6 on the LMH6518 evaluation board. The ribbon cable pin 1 should connect to J6 pin 1 (J6 pin 1 has square pad on the board bottom, and a “1” silk-screened on the top side of the board, for easy identification). Table 1 shows the connections to the USB interface board (for reference only). Table 1.
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Miscellaneous www.ti.com +OUT DC Coupled Hi-Z Input Instrument LMH6518 100: DC Coupled Hi-Z Input Instrument -OUT Figure 2. LMH6518 Output Observation With Hi-Z Instrumentation 3. Input(s): Ensure that the LMH6518 inputs (LMH6518 pins 6 and 7) are both close to VCC/2 (= 2.5 V) and there is less than 1 mV of difference in voltage between them. On the board, use a DC voltmeter to measure LMH6518 pin 6 and 7 voltages (or C14 and R19, right hand side pads).
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Miscellaneous www.ti.com Figure 3. Evaluation Software Screen Shot 3. Default device turn-on state: Preamp low gain, 20 dB ladder attenuation, full-power mode, filter full. With the USB interface board connected, the LMH6518 evaluation board will remain powered on through the interconnect to the USB interface board, even if the 5 V supply to the board is disconnected. Therefore, the device states will not reset to default power-on even if the power is turned off. 4.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.