max5510etct Maxim Integrated Products, Inc., max5510etct Datasheet - Page 16

• Manufacturer Part Number: max5510etct
• Description: +1.8v To +5.5v, Ultra-low-power, 8-bit, Voltage-output Dacs
• Manufacturer: Maxim Integrated Products, Inc.

+1.8V to +5.5V, Ultra-Low-Power, 8-Bit,
Voltage-Output DACs
Figure 8. Bipolar Output Circuit
16
Figure 6. Self-Biased Two-Electrode Potentiostat Application
Figure 7. Unipolar Output Circuit
REFIN
REFIN
______________________________________________________________________________________
REF
MAX5510
MAX5510
DAC
DAC
DAC
BAND
GAP
MAX5511
REFOUT
OUT
10kΩ
FB
OUT
FB
N
(0 TO 255 DECIMAL).
V
I
F
FB
OUT
A
SENSOR
IS THE DAC INPUT CODE
WE
CE
=
OUT
V
REFIN
R
C
F
256
10kΩ
L
V+
V-
× N
A
TO ADC
TO ADC
TO ADC
V
OUT
Figure 7 shows the MAX5510 in a unipolar output con-
figuration with unity gain. Table 4 lists the unipolar out-
put codes.
The MAX5510 output can be configured for bipolar
operation, as shown in Figure 8. The output voltage is
given by the following equation:
where NA represents the numeric value of the DAC’s
binary input code. Table 5 shows digital codes (offset
binary) and the corresponding output voltage for the
circuit in Figure 4.
The MAX5510/MAX5511 have a force-sense output,
which provides a connection directly to the inverting ter-
minal of the output op amp, yielding the most flexibility.
The advantage of the force-sense output is that specific
gains can be set externally for a given application. The
gain error for the MAX5510/MAX5511 is specified in a
unity-gain configuration (op-amp output and inverting ter-
minals connected), and additional gain error results from
external resistor tolerances. Another advantage of the
force-sense DAC is that it allows many useful circuits to
be created with only a few simple external components.
Table 4. Unipolar Code Table (Gain = +1)
Table 5. Bipolar Code Table (Gain = +1)
MSB
1111
1000
1000
0111
0000
0000
MSB
1111
1000
1000
0111
0000
0000
DAC CONTENTS
DAC CONTENTS
1111
0001
0000
1111
0001
0000
1111
0001
0000
1111
0001
0000
V
OUT
= V
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
LSB
LSB
REF
Configurable Output Gain
x [(N
+V
A
-V
REF
- 128) / 128]
REF
ANALOG OUTPUT
ANALOG OUTPUT
+V
+V
+V
+V
-V
+V
+V
(128/256) = +V
-V
Unipolar Output
REF
(128/128) = -V
REF
REF
REF
REF
REF
Bipolar Output
REF
REF
(127/128)
(127/128)
0V
(255/256)
(129/256)
(127/256)
0V
(1/128)
(1/128)
(1/256)
REF
REF
/2