EEVblog #723 - Keysight 34470A 7.5 Digit Multimeter Teardown

What's inside Keysight's new 34470A 7 1/2 digit Truevolt bench multimeter?
What are the PCB changes from the 34461A?
What voltage reference does it use to get 16ppm nominal accuracy?

High res photos: http://www.eevblog.com/2015/03/13/eevblog-723-keysight-34470a-7-5-digit-multimeter-teardown/

Forum: http://www.eevblog.com/forum/blog/eevblog-723-keysight-34470a-7-5-digit-multimeter-teardown/

34470A Datasheet:
http://literature.cdn.keysight.com/litweb/pdf/5991-1983EN.pdf

34470A Operating & Service Manual: http://literature.cdn.keysight.com/litweb/pdf/34460-90901.pdf

LTZ1000 Voltage Reference: http://cds.linear.com/docs/en/datasheet/1000afd.pdf

AD8638 Chopper Amplifier: http://www.analog.com/media/en/technical-documentation/data-sheets/AD8638_8639.pdf

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