max5513 Maxim Integrated Products, Inc., max5513 Datasheet - Page 18

• Manufacturer Part Number: max5513
• Description: Dual, Ultra-low-power, 8-bit, Voltage-output Dacs
• Manufacturer: Maxim Integrated Products, Inc.

See the circuit in
configure the MAX5514/MAX5515 to bias a current-out-
put transducer. In
MAX5514/MAX5515 is a function of the voltage drop
across the transducer added to the voltage drop
across the feedback resistor R.
Figure
figuration with unity gain.
put codes.
The MAX5514 output can be configured for bipolar
operation as shown in
given by the following equation:
where N
binary input code.
set binary) and the corresponding output voltage for
the circuit in
The MAX5514/MAX5515 have force-sense outputs,
which provide 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 MAX5514/MAX5515 is specified in a
unity-gain configuration (op-amp output and inverting
terminals 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.
Dual, Ultra-Low-Power,
8-Bit, Voltage-Output DACs
Figure
18
REFIN
______________________________________________________________________________________
6. Unipolar Output Circuit
6 shows the MAX5514 in a unipolar output con-
A
V
MAX5514
represents the decimal value of the DAC’s
OUT_
Figure
DAC
= V
Figure
Table
Figure
7.
REFIN
Current-Output Transducer
Configurable Output Gain
Figure
5 shows the digital codes (off-
5 for an illustration of how to
Table
x [(N
5, the output voltage of the
7. The output voltage is
A
4 lists the unipolar out-
Voltage Biasing a
- 128) / 128]
Unipolar Output
N
(0 TO 255 DECIMAL).
V
FB_
OUT
A
Bipolar Output
IS THE DAC_ INPUT CODE
=
OUT_
V
REFIN
256
× N
A
Table
Table
An example of a custom fixed gain using the MAX5514/
MAX5515 force-sense output is shown in
this example, R1 and R2 set the gain for V
where N
input code.
Figure
MSB
1111
1000
1000
0111
0000
0000
MSB
1111
1000
1000
0111
0000
0000
REFIN
V
OUTA
DAC CONTENTS
DAC CONTENTS
7. Bipolar Output Circuit
4. Unipolar Code
5. Bipolar Code
A
1/2 MAX5514
= [(V
1111
0001
0000
1111
0001
0000
represents the numeric value of the DAC
1111
0001
0000
1111
0001
0000
DAC
REFIN
0000
0000
0000
0000
0000
0000
LSB
0000
0000
0000
0000
0000
0000
LSB
x N
A
) / 256] x [1 + (R2 / R1)]
Table
+V
10kΩ
Table
-V
REF
ANALOG OUTPUT
REF
ANALOG OUTPUT
+V
+V
+V
OUT_
+V
FB_
-V
+V
(128/256) = +V
+V
-V
REF
REF
REF
REF
(128/128) = -V
REF
(Gain = +1)
REF
REF
REF
(Gain = +1)
(255/256)
(129/256)
(127/256)
0V
(127/128)
(127/128)
0V
(1/256)
(1/128)
10kΩ
(1/128)
OUTA
V+
V-
Figure
.
REF
REF
9. In
V
/2
OUT