Description
Demonstration circuit 2365A highlights the LTC®2358
family of buffered input ADCs. The LTC2358/LTC2357/
LTC2353/LTC2333 are low noise, high speed, 16-/18-
bit successive approximation register (SAR) ADCs with
integrated front end buffers. These ADCs accept a wide
common mode range. Pico-amp inputs and high CMRR
enable these ADCs to connect directly to a wide range of
sensors without compromising measurement accuracy.
The following text refers to the LTC2358-18 but applies
to all parts in the family, the only differences being the
number of bits, number of channels and the maximum
sample rate. The LTC2358-18 has a flexible SoftSpan™
interface that allows conversion-by-conversion control of
the input voltage span on a per-channel basis. An internal
2.048V reference and 2X buffer simplify basic operation
while an external reference can be used to increase the
input range and the SNR of the ADC.
The DC2365A demonstrates the DC and AC performance of
the LTC2358-18 in conjunction with the DC590/DC2026 and
DC890 data collection boards. Use the DC590/DC2026 to
demonstrate DC performance such as peak-to-peak noise
and DC linearity. Use the DC890 if precise sampling rates
are required or to demonstrate AC performance such as
SNR, THD, SINAD and SFDR. The DC2365A is intended
to demonstrate recommended grounding, component
placement and selection, routing and bypassing for this
ADC. A simple driver circuit for the analog inputs is also
presented.