Good afternoon.
I need +/- 5V for a low noise analogue system to be used with a 14-bit 65MS/s ADC. Both +5V and -5V need to source/sink ~2A, need to be regulated and decoupled. The supply is the Hub point power unit for 16-32 photo diode pre-amplifier circuits.
We have a 12V supply available on board, but this is referenced to the global system ground. We are already using the 3A 5V LM108-5.0 so we would prefer to use this to maintain a low BOM.
Others have suggested dual supply generation using buck converters. Unfortunately the switching frequency is likely to be within our 10Hz to 3MHz signal bandwidth.
Some data sheets (LM108 for example) suggest tying 'Vout' to GND and 'Gnd' to be the output voltage. However having never physically done that before, I wonder if it can still drive its rated 3A, if current is flowing through the ICs substrate rather than dedicated output tracking. As it contains a 1.25V band gap reference I presume reverse polarity would really mess things up.
If linear regulators operate find in reverse polarity configuration, just let me know and I'll bash on with our schematics.
Thanks in advance.
Ed