Agilent Technologies E3634A, E3633A manual Theory of Operation D-to-A Converter

Chapter 4 Theory of Operation

D-to-A Converter

D-to-A Converter

Referring to the schematic shown on page 131, all reference voltages of power circuits are derived from the internal voltage reference of system DAC U22. The system DAC track/hold amplifier outputs are used to provide controllable reference voltages to power circuits. The system DAC is programmed and responds to the main controller via internal 3-wire serial data bus SERCLK, SERRBK, and SERSTB. The system DAC is multiplexed to 6 track/hold amplifiers through U26. Each track/hold amplifier is refreshed approximately every 1 msec to maintain its output setting. Changes to track/hold amplifier outputs are accomplished by dwelling on that position for an extended period.

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