December 20, 2007
DAC121C081/ DAC121C085
12-Bit Micro Power Digital-to-Analog Converter with an
I2C-Compatible Interface
General Description
The DAC121C081 is a 12-bit, single channel, voltage-output
digital-to-analog converter (DAC) that operates from a +2.7V
to 5.5V supply. The output amplifier allows rail-to-rail output
swing and has an 8.5usec settling time. The DAC121C081
uses the supply voltage as the reference to provide the widest
dynamic output range and typically consumes 132uA while
operating at 5.0V. It is available in 6-lead TSOT and LLP
packages and provides three address options (pin se-
lectable).
Features
Guaranteed Monotonicity to 12-bits
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Low Power Operation: 156 µA max @ 3.3V
Extended power supply range (+2.7V to +5.5V)
I2C-Compatible 2-wire Interface which supports standard
(100kHz), fast (400kHz), and high speed (3.4MHz) modes
Rail-to-Rail Voltage Output
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Very small 6-pin TSOT and LLP Packages
As an alternative, the DAC121C085 provides nine I2C ad-
dressing options and uses an external reference. It has the
same performance and settling time as the DAC121C081. It
is available in an 8-lead MSOP.
The DAC121C081 and DAC121C085 use a 2-wire, I2C-com-
patible serial interface that operates in all three speed modes,
including high speed mode (3.4MHz). An external address
selection pin allows up to three DAC121C081 or nine
DAC121C085 devices per 2-wire bus. Pin compatible alter-
natives to the DAC121C081 are available that provide addi-
tional address options.
Key Specifications
Resolution
INL
12 bits
±8 LSB (max)
+0.6 / -0.5 LSB (max)
8.5 µs (max)
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DNL
Settling Time
Zero Code Error
Full-Scale Error
Supply Power
+10 mV (max)
−0.7 %FS (max)
Normal
380 µW (3V) / 730 µW (5V) typ
0.5 µW (3V) / 0.9 µW (5V) typ
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Power Down
The DAC121C081 and DAC121C085 each have a 16-bit reg-
ister that controls the mode of operation, the power-down
condition, and the output voltage. A power-on reset circuit
ensures that the DAC output powers up to zero volts. A power-
down feature reduces power consumption to less than a
microWatt. Their low power consumption and small packages
make these DACs an excellent choice for use in battery op-
erated equipment. Each DAC operates over the extended
industrial temperature range of −40°C to +125°C.
Applications
Industrial Process Control
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Portable Instruments
Digital Gain and Offset Adjustment
Programmable Voltage & Current Sources
Test Equipment
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The DAC121C081 and DAC121C085 are each part of a fam-
ily of pin compatible DACs that also provide 8 and 10 bit
resolution. For 8-bit DACs see the DAC081C081 and
DAC081C085. For 10-bit DACs see the DAC101C081 and
DAC101C085.
Pin-Compatible Alternatives
All devices are fully pin and function compatible.
Resolution TSOT-6 and LLP-6 MSOP-8 Package w/
Packages
External Reference
12-bit
10-bit
8-bit
DAC121C081
DAC101C081
DAC081C081
DAC121C085
DAC101C085
DAC081C085
Connection Diagrams
30004901
30004902
30004910
I2C® is a registered trademark of Phillips Corporation.
© 2007 National Semiconductor Corporation
300049
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