Anurag Pulincherry
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Hi,
you can feed the bandgap voltage in to a very slow buffer. The buffer only serves to isolate the original referance voltage generator from the switching noise. To the output of the buffer is taken off-chip, and bypassed say by a 0.01uf in parallel with 0.1uf, they supply all the required charge.
Typically you might have to add a series damping resistor to the capacitor to damp out any oscillations, due to the inductance inherent in the bond wire, board trace etc. Inaddition you also have to model, the inductance of the bus inside the chip that routes the reference. It is advisable to use a flipchip package with multiple bondpads allocated for reference to minimize parasitic inductance.
There are not many references available, try
The scheme here is slightly different, does not use a buffer but just a resistor ladder with external bypass, the principle is the same.
A Highly Integrated Analog Baseband Transceiver Featuring a 12-bit 180MSPS Pipelined A/D Converter for Multi-Channel Wireless LAN, K. Gulati, C. Munoz, S. Cho, G. Manganaro, M. Lugin, M. Peng, A. Pulincherry, J. Li, A. Bugeja, A. Chandrakasan and D. Shoemaker, Engim, Inc., Acton, MA
There is also a paper from Analog devices by Larry singer, don't quite remember which one.
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