Twos Complement, Dual 12-Bit DAC
with Internal REF and Fast Settling Time
AD5399
FEATURES
FUNCTIONAL BLOCK DIAGRAM
VTP
AD5399
VDD
×2
X2
×2
DECODER SW
DRIVER A
AGND
The AD5399 is available in the compact 1.1 mm low profile
MSOP-10 package. All parts are guaranteed to operate over the
extended industrial temperature range of –40°C to +105°C.
VBZ – 2V = 0V
12
DAC A
REGISTER
ADDR
DECODE
VOUTB
DAC B
REGISTER
EN
12
A0
16-BIT
SDI
03469-B-001
CLK
POWER-ON
RESET
D15...D0
Figure 1.
VOUT = ((D – 2048)/4096 × 4 V) + 2 V for 0 ≤ D ≤ 4095, where D
is the decimal code.
Table 1. Examples of Twos Complement Codes
Twos Complement
2047
2046
1
0
4095
2049
2048
D
4095
4094
2049
2048
2047
1
0
Scale
+FS
+FS – 1 LSB
BZS + 1 LSB
BZS
BZS – 1 LSB
–FS + 1 LSB
–FS
VOUT (V)
4.000
3.999
2.001
2.000
1.999
0.001
0.000
FS = Full Scale, BZS = Bipolar Zero Scale.
4.0
3.5
3.0
VOUT = [(0 – 2048)/4096 × 4V] + 2V
2.5
VOUT (V)
The AD5399 is the industry-first dual 12-bit digital-to-analog
converter that accepts twos complement digital coding with 2 V
dc offset for single-supply operation. Augmented with a built-in
precision reference and a solid buffer amplifier, the AD5399 is
the smallest self-contained 12-bit precision DAC that fits many
general-purpose as well as DSP specific applications. The twos
complement programming facilitates the natural coding
implementation commonly found in DSP applications, and
allows operation in single supply. The AD5399 provides a 2 V
reference output, VREF, for bipolar zero monitoring. It can also
be used for other on-board components that require a precision
reference. The device is specified for operation from 5 V ± 10%
single supply with bipolar output swing from 0 V to 4 V
centered at 2 V.
VBZ + 2V = 4V
DECODER SW
DRIVER B
12
CS
APPLICATIONS
GENERAL DESCRIPTION
VOUTA
VREF 2V
DGND
Single-supply bipolar converter operations
General-purpose DSP applications
Digital gain and offset controls
Instrumentation level settings
Disk drive control
Precision motor control
VBZ(VREF) = 2V
2.0
1.5
1.0
0.5
0
0
512
1024
1536
2048
2560
3072
TWOS COMPLEMENT CODE
3584
4096
03469-B-002
2-channel 12-bit DAC
Twos complement facilitates bipolar applications
Bipolar zero with 2 V dc offset
Built-in 2.000 V precision reference with 10 ppm/°C typ TC
Buffered voltage output: 0 V to 4 V
Single-supply operation: 4.5 V to 5.5 V
Fast 0.8 µs settling time typ
Ultracompact MSOP-10 package
Monotonic DNL < ±1 LSB
Optimized accuracy at zero scale
Power-on reset to VREF
3-wire serial data input
Extended temperature range: –40°C to +105°C
Figure 2. Output vs. Twos Complement Code
Rev. D
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