On 12/28/2013 6:54 PM, Randy Evans wrote:
I am in the process of designing an upgrade for a Fluke 845 Null meter to
eliminate the opto-chopper, which doesn't work in most units today. I am
planning on using the Linear Tech LTC2054 zero drift op amp and power it with
two 3V lithium batteries (which charge off the AC when plugged in) that should
allow it to run for many hours on batteries only. The only fly-in-the-ointment
for my plan is to design a low power isolation amplifier for the recorder
output that will work with the two 3VDC lithium batteries. I have found
isolation amplifiers that will work but they have issues such as requiring +/-
15VDC, are uni-polar only, or cost over $100 each. I am still working the
problem but I was hoping that someone on the forum might have a good idea for
an isolation amplifier that works on +/- 3VDC, uses very low power, and will
take in -1 to +1 VDC and output an isolated -1 to +1 VDC.
Randy Evans
_______________________________________________
volt-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
Hi Randy,
Check the new Linear Tech LTC2057 zero drift op amp.
Power supply 4.75V to36V.
* *Supply Voltage Range*
*4.75V to 36V (LTC2057)*
*4.75V to 60V (LTC2057HV)*
* *Offset Voltage: 4?V (Maximum)*
* *Offset Voltage Drift: 0.015?V/°C (Maximum, --40°C to 125°C)*
* *Input Noise Voltage*
*200nV_P-P , DC to 10Hz (Typ)*
*11nV/?Hz, 1kHz (Typ)*
* Input Common Mode Range: V^-- -- 0.1V to V^+ -- 1.5V
* Rail-to-Rail Output
* Unity Gain Stable
* Gain Bandwidth Product: 1.5MHz (Typ)
* Slew Rate: 0.45V/?s (Typ)
* A_VOL : 150dB (Typ)
* PSRR: 160dB (Typ)
* CMRR: 150dB (Typ)
* Shutdown Mode
Thanks,
John Staron
_______________________________________________
volt-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
