DAC122S085
12-Bit Micro Power DUAL Digital-to-Analog Converter
with Rail-to-Rail Output
General Description
The DAC122S085 is a full-featured, general purpose DUAL
12-bit voltage-output digital-to-analog converter (DAC) that
can operate from a single +2.7V to 5.5V supply and uses
210 A at 3V and 320 A at 5V. The DAC122S085 is
packaged in a 10-lead MSOP package. The on-chip output
amplifier allows rail-to-rail output swing and the three wire
serial interface operates at clock rates up to 40 MHz over the
entire supply voltage range. Competitive devices are limited
to 25 MHz clock rates at supply voltages in the 2.7V to 3.6V
range. The serial interface is compatible with standard
SPI
TM
, QSPI, MICROWIRE and DSP interfaces.
The reference for the DAC122S085 serves all four channels
and can vary in voltage between 1V and V
A
, providing the
widest possible output dynamic range. The DAC122S085
has a 16-bit input shift register that controls the outputs to be
updated, the mode of operation, the powerdown condition,
and the binary input data. Both outputs can be updated
simultaneously or individually depending on the setting of
the two mode of operation bits.
A power-on reset circuit ensures that the DAC output powers
up to zero volts and remains there until there is a valid write
to the device. A power-down feature reduces power con-
sumption to less than a microWatt with three different termi-
nation options.
The low power consumption and small packages of the
DAC122S085 make it an excellent choice for use in battery
operated equipment.
The DAC122S085 is one of a family of pin compatible DACs,
including
the
8-bit
DAC082S085
and
the
10-bit
DAC102S085. The DAC122S085 operates over the ex-
tended industrial temperature range of -40C to +105C.
Features
n
Guaranteed Monotonicity
n
Low Power Operation
n
Rail-to-Rail Voltage Output
n
Power-on Reset to 0V
n
Simultaneous Output Updating
n
Wide power supply range (+2.7V to +5.5V)
n
Power Down Modes
Key Specifications
n
Resolution
12 bits
n
INL
8 LSB (max)
n
DNL
+0.7 / -0.5 LSB (max)
n
Settling Time
8.5 s (max)
n
Zero Code Error
+15 mV (max)
n
Full-Scale Error
-0.75 %FS (max)
n
Supply Current
-- Normal
270 A (3.6V) / 410 A (5.5V) max
-- Pwr Down
20 nA (3.6V) / 30 nA (5.5V) typ
Applications
n
Battery-Powered Instruments
n
Digital Gain and Offset Adjustment
n
Programmable Voltage & Current Sources
n
Programmable Attenuators
Pin Configuration
20195202
SPI
TM
is a trademark of Motorola, Inc.
June 2006
DAC122S085
12-Bit
Micro
Power
DUAL
Digital-to-Analog
Converter
with
Rail-to-Rail
Output
2006 National Semiconductor Corporation
DS201952
www.national.com
Ordering Information
Order Numbers
Temperature Range
Package
Top Mark
DAC122S085CIMM
-40C
T
A
+105C
MSOP
X72C
DAC122S085CIMMX
-40C
T
A
+105C
MSOP Tape-and-Reel
X72C
DAC122S085EVAL
Evaluation Board (MSOP)
Block Diagram
20195203
DAC122S085
www.national.com
2
Pin Descriptions
MSOP
Pin No.
Symbol
Type
Description
1
V
A
Supply
Power supply input. Must be decoupled to GND.
2
V
OUTA
Analog Output
Channel A Analog Output Voltage.
3
V
OUTB
Analog Output
Channel B Analog Output Voltage.
4
NC
Not Connected
5
NC
Not Connected
6
GND
Ground
Ground reference for all on-chip circuitry.
7
V
REFIN
Analog Input
Unbuffered reference voltage shared by both channels.
Must be decoupled to GND.
8
D
IN
Digital Input
Serial Data Input. Data is clocked into the 16-bit shift
register on the falling edges of SCLK after the fall of
SYNC.
9
SYNC
Digital Input
Frame synchronization input for the data input. When this
pin goes low, it enables the input shift register and data is
transferred on the falling edges of SCLK. The DAC is
updated on the 16th clock cycle unless SYNC is brought
high before the 16th clock, in which case the rising edge
of SYNC acts as an interrupt and the write sequence is
ignored by the DAC.
10
SCLK
Digital Input
Serial Clock Input. Data is clocked into the input shift
register on the falling edges of this pin.
DAC122S085
www.national.com
3
Absolute Maximum Ratings
(Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage, V
A
6.5V
Voltage on any Input Pin
-0.3V to 6.5V
Input Current at Any Pin (Note 3)
10 mA
Package Input Current (Note 3)
20 mA
Power Consumption at T
A
= 25C
See (Note 4)
ESD Susceptibility (Note 5)
Human Body Model
Machine Model
2500V
250V
Soldering Temperature, Infrared,
10 Seconds (Note 6)
235C
Storage Temperature
-65C to +150C
Operating Ratings
(Notes 1, 2)
Operating Temperature Range
-40C
T
A
+105C
Supply Voltage, V
A
+2.7V to 5.5V
Reference Voltage, V
REFIN
+1.0V to V
A
Digital Input Voltage (Note 7)
0.0V to 5.5V
Output Load
0 to 1500 pF
SCLK Frequency
Up to 40 MHz
Package Thermal Resistances
Package
JA
10-Lead MSOP
240C/W
Electrical Characteristics
Values shown in this table are design targets and are subject to change before product release. The following specifica-
tions apply for V
A
= +2.7V to +5.5V, V
REFIN
= V
A
, C
L
= 200 pF to GND, f
SCLK
= 30 MHz, input code range 48 to 4047. Bold-
face limits apply for T
MIN
T
A
T
MAX
and all other limits are at T
A
= 25C, unless otherwise specified.
Symbol
Parameter
Conditions
Typical
(Note 9)
Limits
(Note 9)
Units
(Limits)
STATIC PERFORMANCE
Resolution
12
Bits (min)
Monotonicity
12
Bits (min)
INL
Integral Non-Linearity
2.4
8
LSB (max)
DNL
Differential Non-Linearity
V
A
= 2.7V to 5.5V
+0.2
+0.7
LSB (max)
-0.1
-0.5
LSB (min)
V
A
= 4.5V to 5.5V (Note 10)
0.15
0.5
LSB (max)
ZE
Zero Code Error
I
OUT
= 0
+4
+15
mV (max)
FSE
Full-Scale Error
I
OUT
= 0
-0.1
-0.75
%FSR
(max)
GE
Gain Error
All ones Loaded to DAC register
-0.2
-1.0
%FSR
ZCED
Zero Code Error Drift
-20
V/C
TC GE
Gain Error Tempco
V
A
= 3V
-0.7
ppm/C
V
A
= 5V
-1.0
ppm/C
OUTPUT CHARACTERISTICS
Output Voltage Range
(Note 10)
0
V
REFIN
V (min)
V (max)
I
OZ
High-Impedance Output
Leakage Current (Note 10)
1
A (max)
ZCO
Zero Code Output
V
A
= 3V, I
OUT
= 200 A
1.3
mV
V
A
= 3V, I
OUT
= 1 mA
6.0
mV
V
A
= 5V, I
OUT
= 200 A
7.0
mV
V
A
= 5V, I
OUT
= 1 mA
10.0
mV
FSO
Full Scale Output
V
A
= 3V, I
OUT
= 200 A
2.984
V
V
A
= 3V, I
OUT
= 1 mA
2.934
V
V
A
= 5V, I
OUT
= 200 A
4.989
V
V
A
= 5V, I
OUT
= 1 mA
4.958
V
DAC122S085
www.national.com
4
Electrical Characteristics
(Continued)
Values shown in this table are design targets and are subject to change before product release. The following specifica-
tions apply for V
A
= +2.7V to +5.5V, V
REFIN
= V
A
, C
L
= 200 pF to GND, f
SCLK
= 30 MHz, input code range 48 to 4047. Bold-
face limits apply for T
MIN
T
A
T
MAX
and all other limits are at T
A
= 25C, unless otherwise specified.
Symbol
Parameter
Conditions
Typical
(Note 9)
Limits
(Note 9)
Units
(Limits)
I
OS
Output Short Circuit Current
V
A
= 3V, V
OUT
= 0V,
Input Code = FFFh
-56
mA
V
A
= 5V, V
OUT
= 0V,
Input Code = FFFh
-69
mA
V
A
= 3V, V
OUT
= 5V,
Input Code = 000h
52
mA
V
A
= 5V, V
OUT
= 5V,
Input Code = 000h
75
mA
I
O
Continuous Output
Current (Note 10)
Available on each DAC output
11
mA (max)
C
L
Maximum Load Capacitance
R
L
=
1500
pF
R
L
= 2k
1500
pF
Z
OUT
DC Output Impedance
7.5
REFERENCE INPUT CHARACTERISTICS
VREFIN
Input Range Minimum
0.2
1.0
V (min)
Input Range Maximum
V
A
V (max)
Input Impedance
60
k
LOGIC INPUT CHARACTERISTICS
I
IN
Input Current (Note 10)
1
A (max)
V
IL
Input Low Voltage (Note 10)
V
A
= 3V
0.9
0.6
V (max)
V
A
= 5V
1.5
0.8
V (max)
V
IH
Input High Voltage (Note 10)
V
A
= 3V
1.4
2.1
V (min)
V
A
= 5V
2.1
2.4
V (min)
C
IN
Input Capacitance (Note 10)
3
pF (max)
POWER REQUIREMENTS
V
A
Supply Voltage Minimum
2.7
V (min)
Supply Voltage Maximum
5.5
V (max)
I
N
Normal Supply Current (output
unloaded)
f
SCLK
= 30 MHz
V
A
= 2.7V
to 3.6V
210
270
A (max)
V
A
= 4.5V
to 5.5V
320
410
A (max)
f
SCLK
= 0
V
A
= 2.7V
to 3.6V
190
A (max)
V
A
= 4.5V
to 5.5V
290
A (max)
I
PD
Power Down Supply Current
(output unloaded, SYNC = 0V
after PD mode loaded)
All PD Modes,
f
SCLK
= 30 MHz
V
A
= 2.7V
to 3.6V
0.02
A (max)
V
A
= 4.5V
to 5.5V
0.03
A (max)
All PD Modes,
f
SCLK
= 0 (Note 10)
V
A
= 2.7V
to 3.6V
0.015
1.0
A (max)
V
A
= 4.5V
to 5.5V
0.025
1.0
A (max)
DAC122S085
www.national.com
5
PDF 
ZIP