551600074-001 National Semiconductor, 551600074-001 Datasheet - Page 5

• Manufacturer Part Number: 551600074-001
• Description: BOARD FOR SOIC LMH6612/19
• Manufacturer: National Semiconductor
• Series: WEBENCH® Buildit Boardr

Specifications of 551600074-001

• Channels Per Ic: 2 - Dual
• Amplifier Type: General Purpose
• Board Type: Bare (Unpopulated)
• Utilized Ic / Part: LMH6612, LMH6619
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Output Type: -
• Current - Output / Channel: -
• Voltage - Supply, Single/dual (±): -
• -3db Bandwidth: -
• Slew Rate: -
• Current - Supply (main Ic): -

A sample Bill of Material (BOM) for a differential to differential
ADC driver board is given in the table below. The ADC driver
will have a cutoff frequency of 500 kHz and a gain of -1.
Measurement Hints
It is important to connect the input source ground with the
supply ground. For each ADC driver configuration, it is im-
portant to account for the impedance of the signal source
when setting up the resistor networks to ensure that the dif-
ferential outputs have the same gain. For example, an audio
precision signal generator has about 22Ω of source
impedance and the typical board termination is 50Ω, so the
gain and input signal must be adjusted in order to obtain the
desired signal at the output of the op amp.
Layout Considerations
The following are recommendations for PCB layout in order
to obtain the optimum high frequency performance:
Designator
C
C
C
C
C
C
C
J1, J3
J2
J4, J5
R
R
R
R
R
U1
1
3
5
7
10
11
13
1
5
6
11
13
, C
, C
, C
, C
, R
, R
, R
, C
, C
, R
, R
2
4
6
8
2
8
7
, C
12
14
, R
, R
12
14
9
3
9
, R
, R
4
10
Single to Single Top Layer
Description
0805 Capacitor
0805 Capacitor
0603 Capacitor
0805 Capacitor
Tantalum Capacitor
0805 Capacitor
0805 Capacitor
SMA Connector
SIP3
Test Point
0805 Capacitor
0805 Capacitor
0805 Capacitor
0805 Capacitor
0805 Capacitor
8-Pin SOIC
30056406
5
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•
•
•
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The top and bottom layouts of all three ADC driver configu-
rations are shown in Figure 4 below.
Place the ADC and amplifier as close together as possible.
Put the supply bypassing capacitors as close as possible
to the device (<1”).
Utilize surface mount components instead of through-hole
components.
Keep the traces short where possible.
Use terminated transmission lines for long traces.
Single to Single Bottom Layer
Comment
1 µF
1 nF
150 pF
0.1 µF
6.8 µF
5.6 µF
220 pF
IN+
Out
Test Point
549
1.24k
14.3k
22
50
LMH6612/LMH6619
www.national.com
30056407