+5V, Low-Power, Voltage-Output,
Serial 12-Bit DACs
MAX531/MAX538/MAX539
CS CLR DIN DOUT
REFOUT V
DD
V
SS
POSITIVE OFFSET
OUTPUT (LSB)
2.048V
SIGNAL
IN
REFIN
INVERTED
R-2R DAC
2R
VOUT
RFB
BIPOFF
MAX531
2R
4
3
2
1
0
1
2 3
4
5
6
7
NEGATIVE OFFSET
8
DAC CODE (LSB)
Figure 9. MAX531 Connected as Four-Quadrant Multiplier. The
unused REFOUT is connected to V
DD
.
Figure 10. Single-Supply Offset
AC Considerations
Digital Feedthrough
High-speed serial data at any of the digital input or output
pins may couple through the DAC package and cause
internal stray capacitance to appear at the DAC output as
noise, even though
CS
is held high (see
Typical Operating
Characteristics).
This digital feedthrough is tested by hold-
ing CS high, transmitting 555 hex from DIN to DOUT.
Analog Feedthrough
Because of internal stray capacitance, higher frequency
analog input signals may couple to the output as shown in
the Analog Feedthrough vs. Frequency graph in the
Typical Operating Characteristics.
It is tested by holding
CS
high, setting the DAC code to all 0s, and sweeping
REFIN.
ANALOG GROUND PLANE
0.1µF
1
2
3
4
5
6
7
14
13
12
11
10
9
8
(a) MAX531 BYPASSING
0.1µF
1
2
3
4
8
7
6
5
0.1µF
(b) MAX538/MAX539 BYPASSING
Figure 11. Power-Supply Bypassing
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13
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
