EEVblog #731 - Keithley DMM7510 7.5 Digit Multimeter Teardown

Inside the new Keithley DMM7510 7.5 Digit Bench Multimeter
What gives this unit it's superb 16ppm/1year accuracy specification?
What construction techniques have they used?
How and why are Fluke so heavily involved?
What considerations are given to the power supply and isolation aspects?
How does it compare with the cheaper Keysight 34770A meter?
UPDATE: The ADC used is a custom 32bit one for slow reading, and an 18bit AD7982 for faster readings. This chip is not marked, and there appears to be two of them on board.

Forum: http://www.eevblog.com/forum/blog/eevblog-731-keithley-dmm7510-7-5-digit-multimeter-teardown/

The Precision Thin Film Resistor Network video: https://www.youtube.com/watch?v=Rxy-VpSDPg4

Hi-Res teardown photos: http://www.eevblog.com/2015/04/09/eevblog-731-keithley-dmm7510-7-5-digit-multimeter-teardown/

Datasheets:
AD7982 18bit ADC: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7982.pdf
LTC1050: http://www.linear.com/product/LTC1050
ISL28110: http://www.intersil.com/en/products/amplifiers-and-buffers/all-amplifiers/amplifiers/ISL28110.html
LSK389 Ultra low noise matched JFET http://www.linearsystems.com/assets/media/file/datasheets/LSK389.pdf
SSM2212 Dual matched transistor: http://www.analog.com/media/en/technical-documentation/data-sheets/SSM2212.pdf
DG411 Precision analog switch: http://www.vishay.com/docs/70050/dg411.pdf
TPS65251 Triple Switcher: http://www.ti.com/product/tps65251
Freescale MPC5125 Processor: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPC5125

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