Operator’s Manual
922258-00 Rev A
69
i.
Set the sine wave generator output frequency to 50 MHz. Be careful not to alter the
output amplitude.
NOTE:
The displayed waveform will be compressed in time to form a solid rectangle.
It is not necessary to alter the time/div setting as long as the peak amplitude can be
measured.
j.
Slowly increase the output frequency of the leveled sine wave generator until the
displayed amplitude decreases to exactly 4.2 divisions. This is a 3 dB reduction in
amplitude.
k.
Record in the Test Record the frequency where the –3 dB amplitude is obtained as
‘Measured –3 dB Frequency at X1 Gain’.
l.
Check that the frequency is > 100 MHz.
m.
Divide 0.35 by the –3 dB frequency (in Hz) recorded in step 4-k. The result is the
calculated rise time. Record the result as ‘Calculated Rise Time at X1 Gain’ in the Test
Record.
5. Check High Frequency CMRR
NOTE
:
Common Mode Rejection Ratio, CMRR, is defined as the
Differential Mode Gain
divided by the Common Mode
Gain (normalized inverse of the Common Mode
Feedthrough). At higher frequencies (>10 MHz) where
the bandwidth of the amplifier begins
to attenuate the differential
mode signal, both the differential mode gain and
common
mode gain feedthrough must be measured to
derive the CMRR.
a.
Make the set-up the same as used for the bandwidth test (Steps 4 a-e). See Figure 17.
Figure 17, X1 and X10 HF CMRR Check Setup.
Summary of Contents for DA1855A
Page 1: ...Operator s Manual DA1855A Differential Amplifier ...
Page 2: ......
Page 3: ...DA1855A Differential Amplifier Operator s Manual February 2013 ...
Page 93: ......
Page 94: ......
