Manufacturer Part Numberdac121c081cimkx
Description12-bit Micro Power Digital-to-analog Converter With An I2c-compatible Interface
ManufacturerNational Semiconductor Corporation
dac121c081cimkx datasheet

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DAC121C081/ DAC121C085
12-Bit Micro Power Digital-to-Analog Converter with an
C-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 8.5µsec settling time. The DAC121C081
uses the supply voltage as the reference to provide the widest
dynamic output range and typically consumes 132µA while
operating at 5.0V. It is available in 6-lead TSOT and LLP
packages and provides three address options (pin se-
As an alternative, the DAC121C085 provides nine I
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, I
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.
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.
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
Connection Diagrams
I2C® is a registered trademark of Phillips Corporation.
© 2008 National Semiconductor Corporation
Guaranteed Monotonicity to 12-bits
Low Power Operation: 156 µA max @ 3.3V
Extended power supply range (+2.7V to +5.5V)
C-Compatible 2-wire Interface which supports standard
(100kHz), fast (400kHz), and high speed (3.4MHz) modes
Rail-to-Rail Voltage Output
Very Small Package
Key Specifications
C ad-
Settling Time
Zero Code Error
Full-Scale Error
Supply Power
— Normal
— Power Down
Industrial Process Control
Portable Instruments
Digital Gain and Offset Adjustment
Programmable Voltage & Current Sources
Test Equipment
Pin-Compatible Alternatives
All devices are fully pin and function compatible.
March 13, 2008
±8 LSB (max)
+0.6 / -0.5 LSB (max)
8.5 µs (max)
+10 mV (max)
−0.7 %FS (max)
380 µW (3V) / 730 µW (5V) typ
0.5 µW (3V) / 0.9 µW (5V) typ
TSOT-6 and LLP-6
MSOP-8 Package w/
External Reference
12 bits

dac121c081cimkx Summary of contents

  • Page 1

    ... For 8-bit DACs see the DAC081C081 and DAC081C085. For 10-bit DACs see the DAC101C081 and DAC101C085. Connection Diagrams 30004901 I2C® registered trademark of Phillips Corporation. © 2008 National Semiconductor Corporation Features ■ Guaranteed Monotonicity to 12-bits ■ Low Power Operation: 156 µA max @ 3.3V ■ ...

  • Page 2

    ... Ordering Information Order Code DAC121C081CIMK DAC121C081CIMKX DAC121C081CISD DAC121C081CISDX DAC121C085CIMM DAC121C085CIMMX DAC121C08XEB Block Diagram www.national.com Temperature Range ≤ ≤ −40°C T +125°C A ≤ ≤ TSOT Tape-and-Reel −40°C T +125°C A ≤ ≤ −40°C T +125°C A ≤ ≤ LLP Tape-and-Reel −40°C T +125° ...

  • Page 3

    Pin Descriptions Symbol Type V Analog Output OUT V Supply A GND Ground Digital SDA Input/Output SCL Digital Input Digital Input, ADR0 three levels Digital Input, ADR1 three levels V Supply REF PAD Ground (LLP only) Package Pinouts V V ...

  • Page 4

    Absolute Maximum Ratings (Notes Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Voltage on any Input Pin Input Current at Any Pin (Note 3) ...

  • Page 5

    Symbol Parameter Output Short Circuit Current SINK Continuous Output I O Current (Note 10) C Maximum Load Capacitance Output Impedance OUT REFERENCE INPUT CHARACTERISTICS- (DAC121C085 only) Input Range Minimum V Input Range Maximum ...

  • Page 6

    Symbol Parameter POWER REQUIREMENTS Supply Voltage Minimum V A Supply Voltage Maximum Normal -- V set to midscale. 2-wire interface quiet (SCL = SDA = V OUT I V DAC121C081 Supply Current ST_VA DAC121C085 Supply Current ST_VA-5 ...

  • Page 7

    A.C. and Timing Characteristics Values shown in this table are design targets and are subject to change before product release. The following specifications apply for V ≤ ≤ and all other limits are at T for MIN ...

  • Page 8

    Symbol Parameter t Rise time of SDA signal rDA t Fall time of SDA signal fDA t Rise time of SCL signal rCL Rise time of SCL signal after a t repeated start condition and after an rCL1 acknowledge bit. ...

  • Page 9

    Note 6: Reflow temperature profiles are different for lead-free packages. Note 7: The inputs are protected as shown below. Input voltage magnitudes up to 5.5V, regardless of V example 3V, the digital input pins can be driven ...

  • Page 10

    Transfer Characteristic Timing Diagrams www.national.com FIGURE 1. Input / Output Transfer Characteristic FIGURE 2. Serial Timing Diagram 10 30004905 30004960 ...

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    Typical Performance Characteristics 4047, unless otherwise stated. INL INL/DNL vs Temperature at V INL/DNL REFIN REF A SCL 30004920 = 3.0V INL/DNL vs Temperature 30004922 = 3.0V A ...

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    INL/DNL vs V Zero Code Error vs. Temperature Full Scale Error vs. Temperature www.national.com A 30004926 30004928 30004929 12 Zero Code Error vs 30004927 Full Scale Error vs 30004936 Total Supply Current vs 30004930 ...

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    V Supply Current vs. V REF Total Supply Current vs. Temperature @ V Power-On Reset Total Supply Current vs. Temperature @ V A 30004931 = 5V A 30004933 30004935 30004932 5V Glitch Response 30004934 www.national.com ...

  • Page 14

    Functional Description 1.1 DAC SECTION The DAC121C081 is fabricated on a CMOS process with an architecture that consists of switches and resistor strings that are followed by an output buffer. For simplicity, a single resistor string is shown in ...

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    SERIAL INTERFACE The I 2 C-compatible interface operates in all three speed modes. Standard mode (100kHz) and Fast mode (400kHz) are functionally the same and will be referred to as Standard- Fast mode in this document. High-Speed mode (3.4MHz) ...

  • Page 16

    High-Speed (Hs) Mode For Hs-mode, the sequence of events to begin communica- tion differ slightly from Standard-Fast mode. Figure 5 de- scribes this in further detail. Initially, the bus begins running in Standard-Fast mode. The master generates a Start ...

  • Page 17

    Writing to the DAC Register To write to the DAC, the master addresses the part with the correct slave address (A6-A0) and writes a "zero" to the read/ write bit. If addressed correctly, the DAC returns an ACK to ...

  • Page 18

    DAC REGISTER The DAC register, Figure 8, has sixteen bits. The first two bits are always zero. The next two bits determine the mode of operation (normal mode or one of three power-down modes). The final twelve bits of ...

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    Applications Information 2.1 USING REFERENCES AS POWER SUPPLIES While the simplicity of the DAC121C081 implies ease of use important to recognize that the path from the reference input (V for the DAC121C081 & V for the DAC121C085) ...

  • Page 20

    LP3985 The LP3985 is a low noise, ultra low dropout voltage regulator with a 3% accuracy over temperature good choice for applications that do not require a precision reference for the DAC121C081. It comes in 3.0V, ...

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    DSP/MICROPROCESSOR INTERFACING Interfacing the DAC121C081 to microprocessors and DSPs is quite simple. The following guidelines are offered to simplify the design process. 2.3.1 Interfacing to the 2-wire Bus Figure 15 shows a microcontroller interfacing to the DAC121C081 via the ...

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    Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 6-Lead TSOT Order Numbers DAC121C081CIMK NS Package Number MK06A 6-Lead LLP Order Numbers DAC121C081CISD NS Package Number SDB06A 22 ...

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    MSOP Order Numbers DAC121C085CIMM NS Package Number MUA08A 23 www.national.com ...

  • Page 24

    ... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...