Op Amp Applications from Analog Devices - Get a Free Blog

3.24
OP AMP APPLICATIONS
On the other hand, Figure 3-25 below shows distortion as a function of output signal level
for a frequencies of 5MHz and 20MHz.
THD @
THD @
Figure 3-25: AD8057/AD8058 op amp distortion versus output voltage
G = +1, RL = 150Ω, VS = ±5V
Whether or not specifications such as those just described are complete enough to select
an op amp for an ADC driver application depends upon the ability to match op amp
specifications to the actually required ADC operating conditions. In many cases, these
comparisons will at least narrow the op amp selection process. The following sections
will examine a number of specific driver circuit examples using various types of ADCs,
ranging from high resolution measurement to high-speed, low distortion applications.
Driving High Resolution Sigma-Delta Measurement ADCs
The AD77XX family of ADCs is optimized for high resolution (16–24 bits) low
frequency transducer measurement applications. Details of operation can be found in
Reference 2, and general characteristics of the family are listed in Figure 3-26 below.
� Resolution: 16 - 24 bits
� Input signal bandwidth: