MAX5661 Datasheet, PDF (27/40 Pages) Maxim Integrated Products – Single 16-Bit DAC with Current and Voltage Outputs for Industrial Analog Output Modules

Single 16-Bit DAC with Current and Voltage
Outputs for Industrial Analog Output Modules
CS
SCLK
DIN
SHIFT
REGISTER
DOUT
MAX5661
CONTROL
REGISTER
INPUT
REGISTER
CLEAR
REGISTER
LDAC
SOFTWARE
LOAD DAC
DAC
REGISTER
FULL-SCALE
ADJUST
REGISTER
2-TO-1
MUX
FULL-SCALE
OUTPUT ADJUST
DAC
TO OUTPUT
CIRCUITRY
OUTI
OUTV
Figure 7. Functional Diagram
Reference Input
Connect an external voltage reference in the +4V to
+4.2V range through a 1kΩ series resistor to
the buffered REF input. Use a high-accuracy, low-
noise +4.096V voltage reference such as the
MAX6126AASA41 (3ppm/°C temperature drift and
0.02% initial accuracy) for best 16-bit static accuracy.
REF does not accept AC signals. See Table 17 for a list-
ing of +4.096V references.
LDAC Input
The MAX5661 features an active-low load DAC (LDAC)
logic input that allows asynchronous updates to the
DAC outputs. Drive LDAC high to V_CC during normal
operation while controlling the MAX5661 using only the
serial interface. Drive LDAC low to update the DAC out-
put with the input register data. Hold LDAC low to make
the input register transparent and immediately update
the DAC output with the input register data. Figure 8
shows the LDAC timing with respect to OUT_.
tLDL
LDAC
OUT_
tDELAY
Figure 8. LDAC Timing
± 2 LSB
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