AMC7891SRHHT datasheet(30/43 Pages) TI2

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10-bit

Resistor String

DACOUTn

dacn_data

DAC Load

(1)

(1) Internal DAC load is generated by writing '1' to the dac_load bit in synchronous mode. In

asynchronous mode, the DAC latch is transparent.

DACn

Data Latch

VOUT

To Output

Amplifier

AMC7891

SBAS518A

– AUGUST 2011 – REVISED DECEMBER 2011

www.ti.com

DAC OPERATION

The AMC7891 contains 4 independent DACs that provide analog control with 10 bits of resolution using an

internal reference. Each DAC core consists of a 10-bit string DAC and an output voltage buffer.

The DAC latch stores the code that determines the output voltage from the DAC string. The code is transferred

from the DACn_data registers to the DACn data latches when the internal DAC load signal is generated.

Figure 33. DAC Block Diagram

The resistor string structure is shown in Figure 34. It consists of a string of resistors, each of value R. The code

loaded to the DAC Latch determines at which node on the string the voltage is tapped off to be fed into the

output amplifier. The voltage is tapped off by closing one of the switches connecting the string to the amplifier.

This architecture has inherent monotonicity, voltage output, and low glitch. It is also linear because all the

resistors are of equal value.

Figure 34. Resistor String

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AMC7891SRHHT Datasheet(PDF) 30 Page - Texas Instruments