Skip to main content
Knowledgebase
Home
Renesas India - Knowledgebase

What level of impedance of external load can be driven without a buffer?

Latest Updated:03/01/2005

Question:

(D/A Converter)  The user's manual states, "The DA output does not have buffers. Accordingly, connect an external buffer when driving a low-impedance load." What level of impedance of external load can be driven without a buffer ? [2005/03/01]

Answer:

Assuming the D/A output allowable margin of error is within 2%, the absolute accuracy of the D/A converter is maximum 1%, so the margin of error for the low-impedance load must be set to within 1%. Therefore, the resistance value of the connected load must be 99 times larger than the output resistance of the D/A converter. If the D/A converter output maximum resistance is 4kΩ, the resistance value of the connected load must be at least 396kΩ (99 times greater).
Note that this is a hypothetical estimation and the resistance values of your actual system should be thoroughly investigated and evaluated. (#104840)
Suitable Products
3803H
3803L