DAC8832 Datasheet, PDF (15/26 Pages) Texas Instruments – 16-Bit, Ultra-Low Power, Voltage-Output Digital-to-Analog Converter

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DAC8832
SBAS380A – FEBRUARY 2006 – REVISED APRIL 2006
THEORY OF OPERATION
GENERAL DESCRIPTION
The DAC8832 is a single, 16-bit, serial-input, voltage-output DAC. It operates from a single supply ranging from
2.7 V to 5 V, and typically consumes 5 µA. Data are written to this device in a 16-bit word format, via an SPI
serial interface. To ensure a known power-up state, the DAC8832 is designed with a power-on reset function.
The DAC8832 is reset to mid-scale code. In unipolar mode, the DAC8832 is reset to 1/2 × V_REF, and in bipolar
mode, is reset to 0 V. Kelvin sense connections for the reference and analog ground are also included.
DIGITAL-TO-ANALOG SECTIONS
The DAC architecture consists of two matched DAC sections and is segmented. A simplified circuit diagram is
shown in Figure 43. The four MSBs of the 16-bit data word are decoded to drive 15 switches, E1 to E15. Each
of these switches connects one of 15 matched resistors to either AGND or V_REF. The remaining 12 bits of the
data word drive switches S0 to S11 of a 12-bit voltage mode R-2R ladder network.
R
R
V_OUT
2R
2R
2R
2R
2R
2R
2R
V_REF
S0
S1
S11
E1
E2
E15
12−Bit R−2R Ladder
Four MSBs Decoded into
15 Equal Segments
Figure 43. DAC Architecture
OUTPUT RANGE
The output of the DAC is:
V_OUT = (V_REF × Code)/65536
Where Code is the decimal data word loaded to the DAC latch.
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