How can I make a isolated 0-50mV voltage source for simulating a thermocouple. The ISO122 isolation amplifier I have tried has 10mV ripple at output

How can I make a isolated 0-50mV voltage source for simulating a thermocouple in a industrial environment. The ISO122 isolation amplifier I have tried has 10mV ripple at the output
 
Hello,

Did you read this section of the datasheet:
BASIC OPERATION
SIGNAL AND SUPPLY CONNECTIONS
Each power supply pin should be bypassed with 1μF tanta-
lum capacitors located as close to the amplifier as possible.
The internal frequency of the modulator/demodulator is set
at 500kHz by an internal oscillator. Therefore, if it is desired
to minimize any feedthrough noise (beat frequencies) from
a DC/DC converter, use a π filter on the supplies (see Figure
4). ISO122 output has a 500kHz ripple of 20mV, which can
be removed with a simple two pole low-pass filter with a
100kHz cutoff using a low cost op amp.
See Figure 4.
The input to the modulator is a current (set by the 200kΩ
integrator input resistor) that makes it possible to have an
input voltage greater than the input supplies, as long as the
output supply is at least ±15V. It is therefore possible when
using an unregulated DC/DC converter to minimize PSR
related output errors with ±5V voltage regulators on the
isolated side and still get the full ±10V input and output
swing. An example of this application is shown in Figure
10.

An other option for lower ripple, is having a larger input signal.
Make an amplifier in front of the ISO122.

Bertus
 

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