bandgap with a buffer

[surianova]

bandgap buffer reference

hi all!


if the bandgap output, i buffer it with a opamp before connect to other circuit as reference voltage, is it fine? accuracy?

 

[qutang]

yes , but the load is too large ,you can use a regulator.

 

[surianova]

yes , but the load is too large ,you can use a regulator.

i found out that if u buffer the bandgap, the DC psrr of the output of the bandgap through buffer will drop a few dB compare to without buffer.

 

[elbadry]

Adding a buffer is very advisable. However it doesn't come at no cost. The major problems would be:

1. Higher power consumption and larger area
2. More noise on the reference voltage (Opamp adds its own noise)
3. A decrease in power supply rejection (since the opamp adds another path to vdd)

 

[protose]

And the buffer OP offset voltage will also be added to the output which could decrease the reference accuracy, but if the voltage is collected at the buffered reference when perform trimming operation, this offset could be canceled.

 

[lijianheng]

Additive noise from buffer is a concern.