LMH6518SQEVK National Semiconductor, LMH6518SQEVK Datasheet - Page 2

• Manufacturer Part Number: LMH6518SQEVK
• Description: KIT EVAL FOR LMH6518 VGA
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LMH6518SQEVK

• Channels Per Ic: 1 - Single
• Amplifier Type: Variable Gain
• Output Type: Differential
• -3db Bandwidth: 900MHz
• Operating Temperature: -40°C ~ 85°C
• Current - Supply (main Ic): 210mA
• Voltage - Supply, Single/dual (±): 4.75 V ~ 5.25 V
• Board Type: Fully Populated
• Utilized Ic / Part: LMH6518
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• Slew Rate: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed

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3.0 Setup and Operation
3.1 PRELIMINARY SETUP
1. Prior to installing the LMH6518 evaluation software (which
2. Download “dotnetfx.exe” and save to any folder on the PC.
3. Follow the LMH6518 Product Folder, “Eval. Boards”, “Buy
4. Go to that folder and run setup.exe. Continue with the in-
5. When the LMH6518 software installation completes, there
6. Apply 5V (±20 mV) DC and ground to the LMH6518 eval-
7. Plug the 10 pin female end of the ribbon cable from the
8. Plug the USB Interface board to a free USB port, with the
is available for download from National Semiconductor
website evaluation board page), you must install
Microsoft .NET Framework version 2.0. Point your brows-
er to this location:
http://www.microsoft.com
and search for “.NET Framework” and continue to the
page link where “Download” is located.
The .NET Framework installation file, “dotnetfx.exe”, can
be downloaded by clicking on “Download” button.
Continue to Run and install this program
Now” and click on the “Software Setup Files”.
stallation.
would be a shortcut to the LMH6518 evaluation software
on the PC desktop. Double click to run the software.
uation board. The power supply should be capable of at
least 300 mA of current. Ensure the power connection to
the evaluation board is properly made or damage may
occur.
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 iden-
tification). Table 1shows the connections to the USB In-
terface board (for reference only):
Note: DI and DO are tied together on the LMH6518 Evaluation board,
other end mating with the USB port on the USB Interface
board, and launch the LMH6518 software, if not already.
If a pop-up window appears, click “yes to upload the cor-
rect setup to the USB Interface board and you are now
ready to control the LMH6518. When the application is
running, you should see “USB Connected All ACK” in the
Status Bar at the bottom-left of the LMH6518 software
window shown in Figure 3. If the status bar message does
TABLE 1. USB Interface Board/ LMH6518 Evaluation
Ground
Name
SCLK
DO
CS
DI
and connected to LMH6518 SDIO pin for bidirectional data read
or write.
Chip Select
(LMH6518
(LMH6518
SDIO pin)
SDIO pin)
Function
Data out
Ground
Data In
Board Interconnect Detail
Clock
bd. pin (J6)
evaluation
LMH6518
1
3
4
5
7
“GND”, pin 2
Board (X4)
A0, pin 15
Interface
A7, pin 1
A6, pin 3
L7, pin 6
USB
2
3.2 LMH6518 EVALUATION BOARD SETUP
Please refer to board schematic and layout documents.
1. Jumper Placement: The LMH6518 evaluation board
2. Outputs: The Main outputs of the LMH6518 appear at J1
3. Input(s):Ensure that the LMH6518 inputs (LMH6518 pins
FIGURE 2. LMH6518 Output Observation with Hi-Z
not appear, un-plug the USB cable and reapply to reiniti-
ate the USB Interface board and until the proper message
appears.
generates the 3.3V logic supply on board (Jumper JP3,
pins 1-2 shorted powers the LMH6518 off the on-board
3.3V source. Note: JP3, pin 1 has a ”1” silk-screened next
to it on the top side of the board). The output common
mode voltage (Main and Auxiliary outputs both) are set to
about 1.2V using an onboard voltage divider (R
from V
level to both Main and Auxiliary common mode inputs
(“V
tively).
and J2 (SMA connectors). These connectors can be tied
directly to a National Semiconductor Gsample/second
ADC (e.g. ADC081500), or equivalent, for DC coupled
data acquisition. Done this way, pin 9 of J6 (V
tied to the common mode output control of the ADC to
allow the ADC to control the LMH6518 output common
mode voltage. Note that R
need to be installed on the evaluation board for this kind
of testing. In addition, move R
R
erence and instead allow the ADC to control the Main and
Auxiliary common mode voltages.
The Auxiliary outputs, which can be terminated in 100Ω
on board by installing R
Note that the Auxiliary outputs (used for Trigger function
in Oscilloscope applications) are very similar to the Main
outputs, with the exception of slightly higher distortion lev-
els. The Auxiliary Outputs are available at J8 and J7 SMA
connectors.
J1, and J2 (and also J7, and J8) differential impedance
should be close to 100Ω with minimal parasitic effects
when being measured. As these outputs are all at approx-
imately 1.2V common mode level, they cannot be termi-
nated in DC coupled 50Ω (similar to an oscilloscope input)
directly. AC coupled 50Ω terminated instrumentation
(such as S parameter analyzers) can be connected to
these SMA outputs directly for observation. With single
ended Hi-Z input instrument observation, the LMH6518
outputs should be terminated in 100Ω differential, as
shown in Figure 2 (beware of the loading effect of such an
observation on the LMH6518 outputs):
6 and 7) are both close to V
than 1 mV of difference in voltage between them. On the
23
CM
and R
” and “V
CC
(+5V). R
24
in order to disconnect the onboard 1.2V ref-
CM_AUX
Instrumentation
21
” which are pins 13 and 16 respec-
and R
4
(100Ω), appear at J8 and J7.
3
CC
22
= 10K and C
/2 (= 2.5V) and there is less
21
(0Ω resistors) tie this 1.2V
and R
22
(0Ω resistors) to
1
= 1 nF would
CMO
1
, and R
30080603
) can be
2
)