Twos Complement, Dual 12-Bit DAC
with Internal REF and Fast Settling Time

AD5399


Rev. D
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FEATURES
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

APPLICATIONS
Single-supply bipolar converter operations
General-purpose DSP applications
Digital gain and offset controls
Instrumentation level settings
Disk drive control
Precision motor control

GENERAL DESCRIPTION
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.
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.
FUNCTIONAL BLOCK DIAGRAM
X2×2
V
REF
2V
×2
DECODER SW
DRIVER A
DECODER SW
DRIVER B
ADDR
DECODE
DAC A
REGISTER
DAC B
REGISTER
16-BIT
D15...D0
POWER-ON
RESET
EN
A0
1212
12
CLK
CS
SDI
DGND
AGND
V
TP
V
DD
V
BZ
+ 2V = 4V
V
BZ
– 2V = 0V
V
OUTA
V
OUTB
V
BZ
(V
REF
) = 2V
AD5399
03469-B-001

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 D Scale VOUT (V)
2047 4095 +FS 4.000
2046 4094 +FS – 1 LSB 3.999
1 2049 BZS + 1 LSB 2.001
0 2048 BZS 2.000
4095 2047 BZS – 1 LSB 1.999
2049 1 –FS + 1 LSB 0.001
2048 0 –FS 0.000
FS = Full Scale, BZS = Bipolar Zero Scale.
V
OUT
= [(0 – 2048)/4096 × 4V] + 2V
0
1.0
0.5
3.0
3.5
2.0
1.5
2.5
4.0
0 512 1024 1536 2048 2560 3072 3584 4096
TWOS COMPLEMENT CODE
V
OUT
(V
)
03469-B
-
002

Figure 2. Output vs. Twos Complement Code