AMC7812SPAPR Datasheet, PDF (40/92 Pages) Texas Instruments – 12-Bit Analog Monitoring and Control Solution with Multichannel ADC, DACs, and Temperature Sensors

AMC7812
SBAS513E – JANUARY 2011 – REVISED SEPTEMBER 2013
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DAC OPERATION
The AMC7812 contains 12 DACs that provide digital control with 12 bits of resolution using an internal or
external reference. The DAC core is a 12-bit string DAC and output buffer. The DAC drives the output buffer to
provide an output voltage. Refer to the DAC Configuration Register for details. Figure 91 shows a function block
diagram of the DAC architecture. The DAC Latch stores the code that determines the output voltage from the
DAC string. The code is transferred from the DAC-n-Data Register to the DAC Latch when the internal DAC-
Load signal is generated.
DAC
Data
Register
DAC
Latch
12-Bit
Resistor
String
DAC Load⁽¹⁾
Gain Bits
Gain Logic
Gain
V_OUT
(1) Internal DAC load is generated by writing '1' to ILDAC bit in synchronous mode. In asynchronous mode, the DAC
latch is transparent.
Figure 91. DAC Block Diagram
Resistor String
The resistor string structure is shown in Figure 92. 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 is inherently monotonic, voltage out, and low glitch. It is also linear because all the resistors are
of equal value.
R
R
R
To Output
Amplifier
R
R
40
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Figure 92. Resistor String
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