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OPA365: Sample and Hold circuit using OPA365

Hirotaka Matsumoto
Guru 27525 points
Part Number: OPA365
Other Parts Discussed in Thread: OPA2365, OPA615

Hi all

Would you mind if we ask OPA365?

Our customer is looking for following a substitute(Sample and Hold circuit device).
https://www.intersil.com/content/dam/Intersil/documents/ha53/ha5351.pdf

The customer will use it(Sample and Hold circuit) as amp buffer for ASIC'S ADC. 
TI doesn't have similar products.(LF398 is out of spec.)

The customer's spec
-Power :3.3V
-Sample rate : 5MHz
-Input : 2CH
-Output :1CH

So, in case of Sample rate : 5MHz, does unity gain require 10 times?
That's why, should we consider OPA2365 + analog switch?

If you have some reference design, could you share it?

Kind regards,

Hirotaka Matsumoto

  • 0
    TI__Intellectual 1910 points

    Hello Hirotaka-san,

    The 50 MHz bandwidth of the OPA2365 should be sufficient for a sample rate of 5 MHz. TIPD142 is a precision reference design that shows how to use a sample and hold circuit to reduce the glitch of a DAC, and it shows a good example of an external sample and hold circuit.

    If it is possible for the customer to use different power supplies, then they could consider the OPA615 which shows an example of it being used in a sample and hold application in Figure 45 on page 19 of the datasheet. However, the minimum supply voltage for the OPA615 is 8V.