OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

MAX5156BCEE+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
__________Applications Information
Unipolar Output
Figure 9 depicts the MAX5156/MAX5157 configured for
unity-gain, unipolar operation. Table 2 lists the unipolar
output codes. To increase dynamic range, specific
gain configurations can be used as shown in Figure 10.
Bipolar Output
The MAX5156/MAX5157 can be configured for a bipo-
lar output, as shown in Figure 11. The output voltage is
given by the equation:
V
OUT
= V
REF
[((2 x NB) / 4096) - 1]
where NB represents the numeric value of the DAC’s
binary input code. Table 3 shows digital codes and the
corresponding output voltage for Figure 11’s circuit.
MAX5156/MAX5157
Low-Power, Dual, 12-Bit Voltage-Output DACs
with Configurable Outputs
______________________________________________________________________________________ 13
TO OTHER
SERIAL DEVICES
MAX5156
MAX5157
DIN
SCLK
CS
MAX5156
MAX5157
DIN
SCLK
CS
MAX5156
MAX5157
DIN
SCLK
CS
DIN
SCLK
CS1
CS2
CS3
Figure 8. Multiple MAX5156/MAX5157s Sharing a Common DIN Line
MAX5156
MAX5157
DAC
REF_
OUT_
FB_
DGND
AGND
+5V/+3V
V
DD
Figure 9. Unipolar Output Circuit
Table 2. Unipolar Code Table (Gain = +1)
0000 0000 0001(0)
0V0000 0000 0000(0)
0111 1111 1111(0)
1000 0000 0000(0)
DAC CONTENTS
MSB LSB
1000 0000 0001(0)
1111 1111 1111(0)
ANALOG OUTPUT
+V
4095
4096
REF
+V
2049
4096
REF
+V
2047
4096
REF
+V
1
4096
REF
+V
2048
4096
V
2
REF
REF
=
Note: ( ) are for the sub bit.
MAX5156/MAX5157
Using an AC Reference
In applications where the reference has an AC signal
component, the MAX5156/MAX5157 have multiplying
capabilities within the reference input voltage range
specifications. Figure 12 shows a technique for apply-
ing a sinusoidal input REF_, where the AC signal is off-
set before being applied to the reference input.
Harmonic Distortion and Noise
The total harmonic distortion plus noise (THD+N) is typ-
ically less than -80dB at full scale with a 1Vp-p input
swing at 5kHz. The typical -3dB frequency is 600kHz
for both devices, as shown in the
Typical Operating
Characteristics
.
Low-Power, Dual, 12-Bit Voltage-Output DACs
with Configurable Outputs
14 ______________________________________________________________________________________
MAX5156
MAX5157
DAC
V
OUT
=
(
1
+ R1
) (
N
)(
V
REF_
)
R2 4096
REF_
V
OUT
FB_
OUT_
AGNDDGND
+5V/+3V
V
DD
R1
R2
Figure 10. Configurable Output Gain
AGNDDGND
MAX5156
MAX5157
DAC _
REF_
OUT_
FB_
10k 10k
V-
V+
V
DD
V
OUT
+5V/+3V
Figure 11. Bipolar Output Circuit
DAC_
OUT_
FB_
MAX5156
MAX5157
10k
26k
REF_
V
DD
DGND AGND
+5V/
+3V
AC
REFERENCE
INPUT
500mVp-p
MAX495
+5V/+3V
Figure 12. AC Reference Input Circuit
Table 3. Bipolar Code Table
0000 0000 0001(0)
0000 0000 0000(0)
0111 1111 1111(0)
0V1000 0000 0000(0)
DAC CONTENTS
MSB LSB
1000 0000 0001(0)
1111 1111 1111(0)
ANALOG OUTPUT
+V
2047
2048
REF
+V
1
2048
REF
-V
1
2048
REF
-V
2047
2048
REF
-V
2048
2098
- V
REF REF
=
Note: ( ) are for the sub bit.
Digital Calibration and
Threshold Selection
Figure 13 shows the MAX5156/MAX5157 in a digital
calibration application. With a bright value applied to
the photodiode (on), the DAC is digitally ramped up
until it trips the comparator. The microprocessor stores
this high calibration value. Repeat the process with a
dim light (off) to obtain the dark current calibration. The
microprocessor then programs the DAC to set an out-
put voltage that is the midpoint of the two calibration
values. Applications include tachometers, motion sens-
ing, automatic readers, and liquid clarity analysis.
Digital Control of Gain and Offset
The two DACs can be used to control the offset and
gain for curve-fitting nonlinear functions, such as trans-
ducer linearization or analog compression/expansion
applications. The input signal is used as the reference
for the gain-adjust DAC, whose output is summed with
the output from the offset-adjust DAC. The relative
weight of each DAC output is adjusted by R1, R2, R3,
and R4 (Figure 14).
MAX5156/MAX5157
Low-Power, Dual, 12-Bit Voltage-Output DACs
with Configurable Outputs
______________________________________________________________________________________ 15
AGND
DIN
µP
DGND
MAX5156
MAX5157
DAC _
REF_
OUT_
R
FB_
V+
V-
PHOTODIODE
V+
V
DD
V
OUT
+5V/+3V
Figure 13. Digital Calibration
AGNDDGND
REFA
CONTROL/
SHIFT REGISTER
REFB
MAX5156
MAX5157
DACA
+5V/+3V
V
DD
V
IN
CS
DIN
SCLK
CL
V
REF
R1
R3
R4
R2
OUT_B
FBB
FBA
OUT_A
V
OUT
DACB
=
NA
4096
NA IS THE NUMERIC VALUE OF THE INPUT CODE FOR DACA.
NB IS THE NUMERIC VALUE OF THE INPUT CODE FOR DACB.
R2
R1+R2
R4
R3
NB
4096
R4
R3
(
V
IN
)(
)(
1+
)
(
V
REF
)(
)
V
OUT
=
[
GAIN
]
-
[
OFFSET
]
[ ] [ ]
Figure 14. Digital Control of Gain and Offset
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

MAX5156BCEE+T

Mfr. #:
Buy MAX5156BCEE+T
Manufacturer:
Maxim Integrated
Description:
Digital to Analog Converters - DAC 12-Bit 2Ch Precision DAC
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet