Chapter 4 Theory of Operation

D-to-A Converter

D-to-A Converter

Referring to the schematic shown on page 129, all reference voltages of power circuits are derived from the internal voltage reference of system DAC U12 on the top board. The system DAC track/hold amplifier outputs are used to provide controllable reference voltages to three 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 mutiplexed to 6 track/hold amplifiers through U13 on the top board. Each track/hold amplifier is refreshed approximately every 13 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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Agilent Technologies E3631A manual Theory of Operation To-A Converter