MAX531 Maxim, MAX531 Datasheet - Page 13

• Manufacturer Part Number: MAX531
• Description: +5V / Low-Power / Voltage-Output / Serial 12-Bit DACs
• Manufacturer: Maxim

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.
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.
Figure 9. MAX531 Connected as Four-Quadrant Multiplier. The
unused REFOUT is connected to V
SIGNAL
IN
REFIN
______________________________________________________________________________________
CS CLR
INVERTED
R-2R DAC
MAX531
DIN DOUT
DD
AC Considerations
2.048V
.
Analog Feedthrough
Digital Feedthrough
REFOUT
+5V, Low-Power, Voltage-Output,
2R
2R
V
DD
BIPOFF
V
VOUT
SS
RFB
Figure 10. Single-Supply Offset
Figure 11. Power-Supply Bypassing
Serial 12-Bit DACs
3
2
1
0
4
(b) MAX538/MAX539 BYPASSING
1
2
3
4
1
2
3
4
5
6
7
1
ANALOG GROUND PLANE
(a) MAX531 BYPASSING
2 3
DAC CODE (LSB)
4
5
6
POSITIVE OFFSET
14
13
12
11
10
8
7
6
5
7
9
8
NEGATIVE OFFSET
8
0.1 F
0.1 F
0.1 F
13