Datasheet

Power Supply

Signal

Generator

Power Source

External

CLK Input

TCXO

LMH2191

BUFFER Out

Oscilloscope

CLK Out

Multi Meter

OUT

Ext

CLK_REQ

signals

CLK_REQ

Signal

Source

Analyzer

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Measurement Setup

4 Measurement Setup

The performance of the LMH2191 can be measured with the setup shown in Figure 3.

To verify all the functions of the part on the evaluation board, it is recommended to have the following

equipment available:

• Multimeter

• Power Supply for dual supply of 5V and single supply of 3.5V

• Oscilloscope

• Signal Generator

Using the default settings, the TCXO is active and its signal is connected to the input of the LMP2191.

Both CLK_REQ inputs are HIGH, which means that both CLK outputs are toggling at the TCXO

frequency. The clock outputs are loaded with 33 pF and can be checked with a high impedance probe on

TP12 (CLK1) and TP13 (CLK2). The clock signals are also connected to SMA edge launch connectors

CON6 (CLK1) and CON7 (CLK2). All three signals (CLK1, CLK2, and TCXO) can be checked via another

edge launch connector (CON8) and this signal is buffered via the LMH6559 and is capable to drive a 50

ohm cable and load. Jumper J2 selects which of the three signals is chosen to appear on this connector.

The best way to check for pulse shape and bandwidth is to make use of the connector CON8.

Figure 3. Test Setup

SNAA071A–July 2010–Revised May 2013 AN-2028 LMH2191 Evaluation Board

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