Sample & Buy Product Folder Support & Community Tools & Software Technical Documents DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 DAC081C08x 8-Bit Micro Power Digital-to-Analog Converter With An I2C-Compatible Interface 1 Features 3 Description • • • • The DAC081C08x device is an 8-bit, single-channel, voltage-output digital-to-analog converter (DAC) that operates from a 2.7-V to 5.5-V supply. The output amplifier allows rail-to-rail output swing and has an 4.5-µsec settling time. The DAC081C081 uses the supply voltage as the reference to provide the widest dynamic output range and typically consumes 132 µA while operating at 5 V. It is available in 6-lead SOT and WSON packages and provides three address options (pin selectable). 1 • • • • • • • • • Ensured Monotonicity to 8-bits Low Power Operation: 156 µA Maximum at 3.3 V Extended Power Supply Range (2.7 V to 5.5 V) I2C-Compatible 2-Wire Interface Which Supports Standard (100-kHz), Fast (400-kHz), and HighSpeed (3.4-MHz) Modes Rail-to-Rail Voltage Output Very Small Package Resolution 8 Bits INL ±0.6 LSB (Maximum) DNL ±0.1 LSB (Maximum) Settling Time 4.5 μs (Maximum) Zero Code Error +10 mV (Maximum) Full-Scale Error −0.7 %FS (Maximum) Supply Power – Normal – 380 μW (3 V) – 730 μW (5 V) Typical – Power Down – 0.5 μW (3 V) – 0.9 μW (5 V) Typical As an alternative, the DAC081C085 provides nine I2C addressing options and uses an external reference. It has the same performance and settling time as the DAC081C081. It is available in an 8-lead VSSOP. The DAC081C081 and DAC081C085 use a 2-wire, I2C-compatible serial interface that operates in all three speed modes, including high-speed mode (3.4 MHz). An external address selection pin allows up to three DAC081C081 or nine DAC081C085 devices per 2-wire bus. Pin-compatible alternatives to the DAC081C081 are available that provide additional address options. Device Information(1) PART NUMBER DAC081C081 2 Applications • • • • • PACKAGE DAC081C085 Industrial Process Control Portable Instruments Digital Gain and Offset Adjustments Programmable Voltage and Current Sources Test Equipment BODY SIZE (NOM) WSON (6) 2.20 mm × 2.50 mm SOT (6) 1.60 mm × 2.90 mm VSSOP (8) 3.00 mm × 3.00 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Block Diagram VA* VREF* GND DAC081C081 / DAC081C085 POWER-ON RESET REF DAC REGISTER 8 BIT DAC VOUT BUFFER 8 8 2.5k 100k POWER-DOWN CONTROL LOGIC 2 I C INTERFACE * NOTE: ADR1 and VREF are for the DAC081C085 only. The DAC081C085 uses an external reference (VREF), whereas, the DAC081C081 uses the supply (VA) as the reference. ADR1* ADR0 SCL SDA 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Description (continued)......................................... Pin Configuration and Functions ......................... Specifications......................................................... 7.1 7.2 7.3 7.4 7.5 7.6 7.7 8 1 1 1 2 3 4 5 Absolute Maximum Ratings ..................................... 5 ESD Ratings.............................................................. 5 Recommended Operating Conditions ...................... 6 Thermal Information .................................................. 6 Electrical Characteristics........................................... 7 AC and Timing Characteristics ............................... 10 Typical Characteristics ............................................ 13 Detailed Description ............................................ 16 8.1 8.2 8.3 8.4 Overview ................................................................. Functional Block Diagram ....................................... Feature Description................................................. Device Functional Modes........................................ 16 16 16 18 8.5 Programming........................................................... 18 8.6 Registers ................................................................. 22 9 Application and Implementation ........................ 23 9.1 Application Information............................................ 23 9.2 Typical Application ................................................. 25 10 Power Supply Recommendations ..................... 26 10.1 Using References as Power Supplies ................. 26 11 Layout................................................................... 29 11.1 Layout Guidelines ................................................. 29 11.2 Layout Example .................................................... 29 12 Device and Documentation Support ................. 30 12.1 12.2 12.3 12.4 12.5 12.6 Device Support .................................................... Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 30 31 31 31 31 31 13 Mechanical, Packaging, and Orderable Information ........................................................... 31 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (March 2013) to Revision E Page • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1 • Added addresses that the DAC responds to on the I2C bus. ............................................................................................. 20 Changes from Revision C (March 2013) to Revision D • 2 Page Changed layout of National Data Sheet to TI format ........................................................................................................... 29 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 5 Description (continued) The DAC081C081 and DAC081C085 each have a 16-bit register that controls the mode of operation, the powerdown 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-operated equipment. Each DAC operates over the extended industrial temperature range of −40°C to +125°C. The DAC081C081 and DAC081C085 are each part of a family of pin-compatible DACs that also provide 12- and 10-bit resolution. For 12-bit DACs see the DAC121C081 and DAC121C085. For 10-bit DACs see the DAC101C081 and DAC101C085. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 3 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 6 Pin Configuration and Functions NGF Package 6-Pin WSON Top View ADR0 1 6 DDC Package 6-Pin SOT Top View VOUT SCL 2 WSON 5 VA SDA 3 GND 4 VOUT 1 VA 2 GND 3 SOT 6 ADR0 5 SCL 4 SDA DAC081C081 DAC081C081 DGK Package 8-Pin VSSOP Top View ADR0 1 8 VOUT ADR1 2 7 VREF SCL 3 6 VA SDA 4 5 GND VSSOP DAC081C085 Pin Functions PIN NAME WSON SOT VSSOP ADR0 1 6 1 EQUIVALENT CIRCUIT TYPE Digital Input, three levels V+ PIN Snap Back D1 41.5k 2.1k 41.5k DESCRIPTION Tri-state Address Selection Input. Sets the two Least Significant Bits (A1 and A0) of the 7-bit slave address. (see Table 1) ADR1 — — 2 Digital Input, three levels GND 4 3 5 Ground Ground for all on-chip circuitry. PAD (WSON only) — — Ground Exposed die attach pad can be connected to ground or left floating. Soldering the pad to the PCB offers optimal thermal performance and enhances package self-alignment during reflow. SCL 2 5 3 Digital Input Serial Clock Input. SCL is used together with SDA to control the transfer of data in and out of the device. GND PIN SDA 3 4 4 Digital Input/Output Snap Back D1 GND Tri-state Address Selection Input. Sets Bits A6 and A3 of the 7-bit slave address. (see Table 1) Serial Data bidirectional connection. Data is clocked into or out of the internal 16-bit register relative to the clock edges of SCL. This is an open drain data line that must be pulled to the supply (VA) by an external pullup resistor. VA 5 2 6 Supply Power supply input. For the SOT and WSON versions, this supply is used as the reference. Must be decoupled to GND. VOUT 6 1 8 Analog Output Analog Output Voltage VREF — — 7 Supply Unbufferred reference voltage. For the VSSOP-8, this supply is used as the reference. VREF must be free of noise and decoupled to GND. 4 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 7 Specifications 7.1 Absolute Maximum Ratings See (1) (2) (3) MIN MAX UNIT Supply voltage, VA −0.3 6.5 V Voltage on any Input Pin −0.3 Input current at any pin (4) Package input current (4) Power consumption at TA = 25°C See Junction temperature −65 Storage temperature, Tstg (1) (2) (3) (4) (5) 6.5 V ±10 mA ±20 mA 150 °C 150 °C (5) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltages are measured with respect to GND = 0 V, unless otherwise specified. If Military/Aerospace specified devices are required, please contact the TI Sales Office/Distributors for availability and specifications. When the input voltage at any pin exceeds 5.5 V or is less than GND, the current at that pin should be limited to 10 mA. The 20-mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 10 mA to two. The absolute maximum junction temperature (TJmax) for this device is 150°C. The maximum allowable power dissipation is dictated by TJmax, the junction-to-ambient thermal resistance (RθJA), and the ambient temperature (TA), and can be calculated using the formula PDMAX = (TJmax − TA) / RθJA. The values for maximum power dissipation will be reached only when the device is operated in a severe fault condition (for example, when input or output pins are driven beyond the operating ratings, or the power supply polarity is reversed). 7.2 ESD Ratings VALUE UNIT DAC081C081 in NGF Package Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 V(ESD) Electrostatic discharge All pins except 2 and 3 ±2500 Pins 2 and 3 ±5000 Charged-device model (CDM), per JEDEC All pins except 2 and 3 specification JESD22-C101 Pins 2 and 3 ±1000 All pins except 2 and 3 ±250 Pins 2 and 3 ±350 All pins except 4 and 5 ±2500 Pins 4 and 5 ±5000 Machine model (MM) ±1000 V DAC081C081 in DDC Package Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 V(ESD) Electrostatic discharge Charged-device model (CDM), per JEDEC All pins except 4 and 5 specification JESD22-C101 Pins 4 and 5 ±1000 All pins except 4 and 5 ±250 Pins 4 and 5 ±350 All pins except 3 and 4 ±2500 Pins 3 and 4 ±5000 Machine model (MM) ±1000 V DAC081C085 in DGK Package Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 V(ESD) Electrostatic discharge Charged-device model (CDM), per JEDEC All pins except 3 and 4 specification JESD22-C101 Pins 3 and 4 ±1000 All pins except 3 and 4 ±250 Pins 3 and 4 ±350 Machine model (MM) Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 ±1000 Submit Documentation Feedback V 5 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 7.3 Recommended Operating Conditions (1) See MIN NOM MAX UNIT −40 TA Operating Temperature Supply Voltage, VA Reference Voltage, VREFIN 125 °C 2.7 5.5 V 1 VA V 5.5 V 1500 pF Digital Input Voltage (2) Output Load (1) (2) 0 All voltages are measured with respect to GND = 0 V, unless otherwise specified. The inputs are protected as shown below. Input voltage magnitudes up to 5.5 V, regardless of VA, will not cause errors in the conversion result. For example, if VA is 3 V, the digital input pins can be driven with a 5V logic device. I/O TO INTERNAL CIRCUITRY GND 7.4 Thermal Information DAC081C081 THERMAL METRIC (1) (2) RθJA (1) (2) 6 Junction-to-ambient thermal resistance DAC081C085 NGF (WSON) DDC (SOT) DGK (VSSOP) 6 PINS 6 PINS 8 PINS 190 250 240 UNIT °C/W For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. Soldering process must comply with Reflow Temperature Profile specifications. Refer to http://www.ti.com/packaging. Reflow temperature profiles are different for lead-free packages. Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 7.5 Electrical Characteristics The following specifications apply for VA = 2.7 V to 5.5 V, VREF = VA, CL = 200 pF to GND, input code range 3 to 252. All Maximum and Minimum limits apply for TMIN ≤ TA ≤ TMAX and all Typical limits are at TA = 25°C, unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP (1) MAX (1) UNIT STATIC PERFORMANCE INL Resolution 8 Monotonicity 8 Bits Bits 0.14 Integral non-linearity −0.6 −0.14 −0.1 −0.02 0.04 0.6 LSB LSB 0.1 LSB DNL Differential non-linearity ZE Zero code error IOUT = 0 1.1 10 FSE Full-scale error IOUT = 0 −0.1 −0.7 %FSR GE Gain error All ones loaded to DAC register −0.2 −0.7 %FSR ZCED Zero code error drift TC GE Gain error tempco LSB mV −20 µV/°C VA = 3 V −0.7 ppm FSR/°C VA = 5 V −1 ppm FSR/°C ANALOG OUTPUT CHARACTERISTICS (VOUT) Output voltage range (2) ZCO Zero code output FSO Full-scale output Output short circuit current (ISOURCE) IOS Output short circuit current (ISINK) IOS IO Continuous output current (2) CL Maximum load capacitance ZOUT DC output impedance (1) (2) DAC081C085 0 DAC081C081 0 VREF VA V V VA = 3 V, IOUT = 200 µA 1.3 mV VA = 5 V, IOUT = 200 µA 7 mV VA = 3 V, IOUT = 200 µA 2.984 V VA = 5 V, IOUT = 200 µA 4.989 V VA = 3 V, VOUT = 0 V, input code = FFFh. 56 mA VA = 5 V, VOUT = 0 V, input code = FFFh. 69 mA VA = 3 V, VOUT = 3 V, input code = 000h. −52 mA VA = 5 V, VOUT = 5 V, input code = 000h. −75 mA Available on the DAC output 11 mA RL = ∞ 1500 pF RL = 2kΩ 1500 pF 7.5 Ω Typical figures are at TJ = 25°C, and represent most likely parametric norms. Test limits are specified to TI's AOQL (Average Outgoing Quality Level). This parameter is ensured by design and/or characterization and is not tested in production. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 7 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Electrical Characteristics (continued) The following specifications apply for VA = 2.7 V to 5.5 V, VREF = VA, CL = 200 pF to GND, input code range 3 to 252. All Maximum and Minimum limits apply for TMIN ≤ TA ≤ TMAX and all Typical limits are at TA = 25°C, unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP (1) 1 0.2 MAX (1) UNIT REFERENCE INPUT CHARACTERISTICS- (DAC081C085 only) Input range minimum VREF Input range maximum V VA Input impedance 120 V kΩ LOGIC INPUT CHARACTERISTICS (SCL, SDA) VIH Input high voltage VIL Input low voltage IIN Input current CIN Input pin capacitance (2) VHYST Input hysteresis 0.7 × VA V 0.3 × VA V ±1 µA 3 pF 0.1 × VA V LOGIC INPUT CHARACTERISTICS (ADR0, ADR1) VIH Input high voltage VIL Input low voltage VA – 0.5 0.5 V V IIN Input current ±1 µA ISINK = 3 mA 0.4 V ISINK = 6 mA 0.6 V ±1 µA LOGIC OUTPUT CHARACTERISTICS (SDA) VOL Output low voltage IOZ High-impedence output leakage current POWER REQUIREMENTS Supply voltage minimum VA 2.7 Supply voltage maximum 5.5 V NORMAL -- VOUT SET TO MIDSCALE. 2-WIRE INTERFACE QUIET (SCL = SDA = VA) (OUTPUT UNLOADED) IST_VA-1 VA = 2.7 V to 3.6 V 105 156 µA VA = 4.5 V to 5.5 V 132 214 µA VA = 2.7 V to 3.6 V 86 118 µA VA = 4.5 V to 5.5 V 98 152 µA VREF supply current (DAC081C085 only) VA = 2.7 V to 3.6 V 37 43 µA 53 61 Power consumption (VA & VREF for DAC081C085) VA = 3 V 380 µW VA = 5 V 730 µW VA DAC081C081 supply current IST_VA-5 VA DAC081C085 supply current IST_VREF PST VA = 4.5 V to 5.5 V µA CONTINUOUS OPERATION -- 2-WIRE INTERFACE ACTIVELY ADDRESSING THE DAC AND WRITING TO THE DAC REGISTER (OUTPUT UNLOADED) fSCL = 400 kHz ICO_VA-1 VA DAC081C081 supply current fSCL = 3.4 MHz 8 Submit Documentation Feedback VA = 2.7 V to 3.6 V 134 220 µA VA = 4.5 V to 5.5 V 192 300 µA VA = 2.7 V to 3.6 V 225 320 µA VA = 4.5 V to 5.5 V 374 500 µA Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Electrical Characteristics (continued) The following specifications apply for VA = 2.7 V to 5.5 V, VREF = VA, CL = 200 pF to GND, input code range 3 to 252. All Maximum and Minimum limits apply for TMIN ≤ TA ≤ TMAX and all Typical limits are at TA = 25°C, unless otherwise specified. PARAMETER fSCL = 400 kHz ICO_VA-5 VA DAC081C085 supply current fSCL = 3.4 MHz ICO_VREF VREF supply current (DAC081C085 only) fSCL = 400 kHz PCO TYP (1) MAX (1) VA = 2.7 V to 3.6 V 101 155 µA VA = 4.5 V to 5.5 V 142 220 µA VA = 2.7 V to 3.6 V 193 235 µA VA = 4.5 V to 5.5 V 325 410 µA VA = 2.7 V to 3.6 V 33.5 55 µA VA = 4.5 V to 5.5 V 49.5 71.4 µA TEST CONDITIONS Power consumption (VA and VREF for DAC081C085) fSCL = 3.4 MHz MIN UNIT VA = 3 V 480 µW VA = 5 V 1.06 mW VA = 3 V 810 µW VA = 5 V 2.06 mW POWER DOWN -- 2-WIRE INTERFACE QUIET (SCL = SDA = VA) AFTER PD MODE WRITTEN TO DAC REGISTER (OUTPUT UNLOADED) IPD PPD Supply current All power-down (VA and VREF for DAC081C085) modes Power consumption All power-down (VA and VREF for DAC081C085) modes VA = 2.7 V to 3.6 V 0.13 1.52 µA VA = 4.5 V to 5.5 V 0.15 3.25 µA VA = 3 V 0.5 µW VA = 5 V 0.9 µW Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 9 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 7.6 AC and Timing Characteristics The following specifications apply for VA = 2.7 V to 5.5 V, VREF = VA, RL = Infinity, CL = 200 pF to GND. All Maximum and Minimum limits apply for TMIN ≤ TA ≤ TMAX and all Typical limits are at TA = 25°C, unless otherwise specified. TEST CONDITIONS (1) PARAMETER ts Output voltage settling time (3) SR Output slew rate Glitch impulse MIN 40h to C0h code change RL = 2 kΩ, CL = 200 pF Code change from 80h to 7Fh Digital feedthrough Multiplying bandwidth (4) Total harmonic distortion tWU VREF = 2.5 V ± 0.1 Vpp (4) Wake-up time TYP (2) MAX (1) (2) 3 4.5 UNIT µs 1 V/µs 12 nV-sec 0.5 nV-sec 160 kHz VREF = 2.5 V ± 0.1 Vpp input frequency = 10 kHz 70 dB VA = 3 V 0.8 µsec VA = 5 V 0.5 µsec DIGITAL TIMING SPECS (SCL, SDA) fSCL Serial clock frequency tLOW SCL low time Standard mode 100 Fast mode 400 High-speed mode, Cb = 100 pF 3.4 High-speed mode, Cb = 400 pF 1.7 Standard mode 4.7 Fast mode 1.3 High-speed mode, Cb = 100 pF 160 High-speed mode, Cb = 400 pF 320 Standard mode tHIGH tSU;DAT SCL high time Data set-up time 0.6 High-speed mode, Cb = 100 pF 60 High-speed mode, Cb = 400 pF 120 Standard mode 250 Fast mode 100 High-speed mode tHD;DAT tSU;STA Data hold time Set-up time for a start or a repeated start condition tHD;STA Hold time for a start or a repeated start condition tBUF Bus free time between a stop and start condition tSU;STO Set-up time for a stop condition (3) (4) 10 µs ns ns 10 0 3.45 Fast mode 0 0.9 High-speed mode, Cb = 100 pF 0 70 High-speed mode, Cb = 400 pF 0 150 Standard mode 4.7 Fast mode 0.6 High-speed mode 160 4 Fast mode 0.6 High-speed mode 160 Standard mode 4.7 Fast mode 1.3 Standard mode (1) (2) ns Standard mode Standard mode MHz µs 4 Fast mode kHz 4 Fast mode 0.6 High-speed mode 160 µs ns µs ns µs ns µs µs ns Cb refers to the capacitance of one bus line. Cb is expressed in pF units. Typical figures are at TJ = 25°C, and represent most likely parametric norms. Test limits are specified to TI's AOQL (Average Outgoing Quality Level). This parameter is ensured by design and/or characterization and is not tested in production. Applies to the Multiplying DAC configuration. In this configuration, the reference is used as the analog input. The value loaded in the DAC Register will digitally attenuate the signal at Vout. Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 AC and Timing Characteristics (continued) The following specifications apply for VA = 2.7 V to 5.5 V, VREF = VA, RL = Infinity, CL = 200 pF to GND. All Maximum and Minimum limits apply for TMIN ≤ TA ≤ TMAX and all Typical limits are at TA = 25°C, unless otherwise specified. TEST CONDITIONS (1) PARAMETER MIN TYP (2) Standard mode trDA Rise time of SDA signal Fast mode 20 + 0.1 Cb 300 High-speed mode, Cb = 100 pF 10 80 High-speed mode, Cb = 400 pF 20 160 Fall time of SDA signal Fast mode 250 High-speed mode, Cb = 100 pF 10 80 High-speed mode, Cb = 400 pF 20 160 Standard mode trCL Rise time of SCL signal 300 High-speed mode, Cb = 100 pF 10 40 High-speed mode, Cb = 400 pF 20 Rise time of SCL signal after a Fast mode repeated start condition and after High-speed mode, Cb = 100 pF an acknowledge bit. High-speed mode, Cb = 400 pF 80 20 + 0.1 Cb 300 10 80 20 160 300 High-speed mode, Cb = 100 pF 10 40 High-speed mode, Cb = 400 pF 20 80 Fall time of a SCL signal Cb Capacitive load for each bus line (SCL and SDA) tSP Pulse width of spike suppressed (5) (3) toutz SDA output delay (see Additional Fast mode Timing Information: toutz) High-speed mode (5) ns 300 20 + 0.1 Cb tfCL ns 1000 Standard mode Fast mode ns 1000 20 + 0.1 Cb Standard mode trCL1 ns 250 20 + 0.1 Cb Fast mode UNIT 1000 Standard mode tfDA MAX (1) (2) 400 Fast mode 50 High-speed mode 10 87 270 38 60 ns pF ns ns Spike suppression filtering on SCL and SDA will supress spikes that are less than 50ns for standard-fast mode and less than 10ns for hs-mode. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 11 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com FSE 255 x VREF 256 GE = FSE - ZE FSE = GE + ZE OUTPUT VOLTAGE ZE 0 0 255 DIGITAL INPUT CODE Figure 1. Input / Output Transfer Characteristic SDA tLOW tf tr tHD;STA tr tf tBUF tSP SCL tSU;STA tHD;STA tHD;DAT START tHIGH tSU;STO tSU;DAT STOP REPEATED START START Figure 2. Serial Timing Diagram 12 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 7.7 Typical Characteristics VREF = VA, fSCL = 3.4 MHz, TA = 25°C, Input Code Range 3 to 252, unless otherwise stated. Figure 3. INL Figure 4. DNL Figure 5. INL/DNL vs Temperature at VA = 3 V Figure 6. INL/DNL vs Temperature at VA = 5 V Figure 7. INL/DNL vs VREFIN at VA = 3 V Figure 8. INL/DNL vs VREFIN at VA = 5 V Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 13 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Typical Characteristics (continued) VREF = VA, fSCL = 3.4 MHz, TA = 25°C, Input Code Range 3 to 252, unless otherwise stated. 14 Figure 9. INL/DNL vs VA Figure 10. Zero Code Error vs VA Figure 11. Zero Code Error vs Temperature Figure 12. Full Scale Error vs VA Figure 13. Full Scale Error vs Temperature Figure 14. Total Supply Current vs VA Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Typical Characteristics (continued) VREF = VA, fSCL = 3.4 MHz, TA = 25°C, Input Code Range 3 to 252, unless otherwise stated. Figure 15. VREF Supply Current vs VA Figure 16. Total Supply Current vs Temperature at VA = 3 V Figure 17. Total Supply Current vs Temperature at VA = 5 V Figure 18. 5-V Glitch Response Figure 19. Power-ON Reset Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 15 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 8 Detailed Description 8.1 Overview The DAC081C081 is fabricated on a CMOS process with an architecture that consists of switches and resistor strings that are followed by an output buffer. 8.2 Functional Block Diagram VA* VREF* GND DAC081C081 / DAC081C085 POWER-ON RESET REF DAC REGISTER 8 BIT DAC VOUT BUFFER 8 8 2.5k 100k POWER-DOWN CONTROL LOGIC 2 I C INTERFACE * NOTE: ADR1 and VREF are for the DAC081C085 only. The DAC081C085 uses an external reference (VREF), whereas, the DAC081C081 uses the supply (VA) as the reference. ADR1* ADR0 SCL SDA 8.3 Feature Description 8.3.1 DAC Section For simplicity, a single resistor string is shown in Figure 20. This string consists of 256 equal-valued resistors with a switch at each junction of two resistors, plus a switch to ground. The code loaded into the DAC register determines which switch is closed, connecting the proper node to the amplifier. The input coding is straight binary with an ideal output voltage of Equation 1: VOUT = VREF × (D / 256) where • D is the decimal equivalent of the binary code that is loaded into the DAC register. (1) D can take on any integer value between 0 and 255. This configuration ensures that the DAC is monotonic. 16 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Feature Description (continued) VREF R R R To Output Amplifier R R Figure 20. DAC Resistor String 8.3.2 Output Amplifier The output amplifier is rail-to-rail, providing an output voltage range of 0 V to VA when the reference is VA. All amplifiers, even rail-to-rail types, exhibit a loss of linearity as the output approaches the supply rails (0V and VA, in this case). For this reason, linearity is specified over less than the full output range of the DAC. However, if the reference is less than VA, there is only a loss in linearity in the lowest codes. The output capabilities of the amplifier are described in the Electrical Characteristics. The output amplifiers are capable of driving a load of 2 kΩ in parallel with 1500 pF to ground or to VA. The zerocode and full-scale outputs for given load currents are available in the Electrical Characteristics. 8.3.3 Reference Voltage The DAC081C081 uses the supply (VA) as the reference. With that said, VA must be treated as a reference. The Analog output will only be as clean as the reference (VA). It is recommended that the reference be driven by a voltage source with low output impedance. The DAC081C085 comes with an external reference supply pin (VREF). For the DAC081C085, it is important that VREF be kept as clean as possible. The Application and Implementation section describes a handful of ways to drive the reference appropriately. Refer to Using References as Power Supplies for details. 8.3.4 Power-On Reset The power-on reset circuit controls the output voltage of the DAC during power up. Upon application of power, the DAC register is filled with zeros and the output voltage is 0 Volts. The output remains at 0 V until a valid write sequence is made to the DAC. When resetting the device, it is crucial that the VA supply be lowered to a maximum of 200 mV before the supply is raised again to power up the device. Dropping the supply to within 200 mV of GND during a reset will ensure the ADC performs as specified. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 17 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Feature Description (continued) 8.3.5 Simultaneous Reset The broadcast address allows the I2C master to write a single word to multiple DACs simultaneously. Provided that all of the DACs exist on a single I2C bus, every DAC will update when the broadcast address is used to address the bus. This feature allows the master to reset all of the DACs on a shared I2C bus to a specific digital code. For instance, if the master writes a power-down code to the bus with the broadcast address, all of the DACs will power-down simultaneously. 8.3.6 Additional Timing Information: toutz The toutz specification is provided to aid the design of the I2C bus. After the SCL bus is driven low by the I2C master, the SDA bus will be held for a short time by the DAC081C081. This time is referred to as toutz. The following figure illustrates the relationship between the fall of SCL, at the 30% threshold, to the time when the DAC begins to transition the SDA bus. The toutz specification only applies when the DAC is in control of the SDA bus. The DAC is only in control of the bus during an ACK by the DAC081C081 or a data byte read from the DAC (see Figure 25). SCL SDA toutz Figure 21. Data Output Timing The toutz specification is typically 87 ns in standard-fast mode and 38 ns in Hs-Mode. 8.4 Device Functional Modes 8.4.1 Power-Down Modes The DAC081C081 has three power-down modes. In power-down mode, the supply current drops to 0.13 µA at 3 V and 0.15 µA at 5 V (typical). The DAC081C081 is put into power-down mode by writing a one to PD1 and/or PD0. The outputs can be set to high impedance, terminated by 2.5 kΩ to GND, or terminated by 100 kΩ to GND (see Figure 26). The bias generator, output amplifier, resistor string, and other linear circuitry are all shut down in any of the power-down modes. When the DAC081C081 is powered down, the value written to the DAC register, including the power-down bits, is saved. While the DAC is in power-down, the saved DAC register contents can be read back. When the DAC is brought out of power-down mode, the DAC register contents will be overwritten and VOUT will be updated with the new 8-bit data value. The time to exit power-down (wake-up time) is typically 0.8 µs at 3 V and 0.5 µs at 5 V. 8.5 Programming 8.5.1 Serial Interface The I2C-compatible interface operates in all three speed modes. Standard mode (100 kHz) and fast mode (400 kHz) are functionally the same and will be referred to as standard-fast mode in this document. High-speed mode (3.4 MHz) is an extension of standard-fast mode and will be referred to as Hs-mode in this document. The following diagrams describe the timing relationships of the clock (SCL) and data (SDA) signals. Pullup resistors or current sources are required on the SCL and SDA busses to pull them high when they are not being driven low. A logic zero is transmitted by driving the output low. A logic high is transmitted by releasing the output and allowing it to be pulled up externally. The appropriate pullup resistor values will depend upon the total bus capacitance and operating speed. 18 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Programming (continued) 8.5.2 Basic I2C Protocol The I2C interface is bidirectional and allows multiple devices to operate on the same bus. To facilitate this bus configuration, each device has a unique hardware address which is referred to as the slave address. To communicate with a particular device on the bus, the controller (master) sends the slave address and listens for a response from the slave. This response is referred to as an acknowledge bit. If a slave on the bus is addressed correctly, it acknowledges (ACKs) the master by driving the SDA bus low. If the address doesn't match a device's slave address, it not-acknowledges (NACKs) the master by letting SDA be pulled high. ACKs also occur on the bus when data is being transmitted. When the master is writing data, the slave ACKs after every data byte is successfully received. When the master is reading data, the master ACKs after every data byte is received to let the slave know it wants to receive another data byte. When the master wants to stop reading, it NACKs after the last data byte and creates a Stop condition on the bus. All communication on the bus begins with either a start condition or a repeated start condition. The protocol for starting the bus varies between standard-fast mode and Hs-mode. In standard-fast mode, the master generates a start condition by driving SDA from high to low while SCL is high. In Hs-mode, starting the bus is more complicated. Please refer to High-Speed (Hs) Mode for the full details of a Hs-mode start condition. A repeated start is generated to either address a different device, or switch between read and write modes. The master generates a repeated start condition by driving SDA low while SCL is high. Following the repeated start, the master sends out the slave address and a read/write bit as shown in Figure 22. The bus continues to operate in the same speed mode as before the repeated start condition. All communication on the bus ends with a stop condition. In either standard-fast mode or Hs-Mode, a stop condition occurs when SDA is pulled from low to high while SCL is high. After a stop condition, the bus remains idle until a master generates a start condition. Please refer to the Phillips I2C Specification (Version 2.1 Jan, 2000) for a detailed description of the serial interface. SDA 1 2 6 MSB R/W Direction Bit Acknowledge from the Device 7-bit Slave Address SCL ACK LSB MSB 7 8 9 LSB N/ACK Data Byte *Acknowledge or Not-ACK 1 2 8 Repeated for the Lower Data Byte and Additional Data Transfers START or REPEATED START 9 STOP *Note: In continuous mode, this bit must be an ACK from the data receiver. Immediately preceding a STOP condition, this bit must be a NACK from the master. Figure 22. Basic Operation 8.5.3 Standard-Fast Mode In standard-fast mode, the master generates a start condition by driving SDA from high to low while SCL is high. The start condition is always followed by a 7-bit slave address and a read/write bit. After these eight bits have been transmitted by the master, SDA is released by the master and the DAC081C081 either ACKs or NACKs the address. If the slave address matches, the DAC081C081 ACKs the master. If the address doesn't match, the DAC081C081 NACKs the master. For a write operation, the master follows the ACK by sending the upper eight data bits to the DAC081C081. Then the DAC081C081 ACKs the transfer by driving SDA low. Next, the lower eight data bits are sent by the master. The DAC081C081 then ACKs the transfer. At this point, the DAC output updates to reflect the contents of the 16-bit DAC register. Next, the master either sends another pair of data bytes, generates a stop condition to end communication, or generates a repeated start condition to communicate with another device on the bus. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 19 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Programming (continued) For a read operation, the DAC081C081 sends out the upper eight data bits of the DAC register. This is followed by an ACK by the master. Next, the lower eight data bits of the DAC register are sent to the master. The master then produces a NACK by letting SDA be pulled high. The NACK is followed by a master-generated stop condition to end communication on the bus, or a repeated start to communicate with another device on the bus. 8.5.4 High-Speed (Hs) Mode For Hs-mode, the sequence of events to begin communication differ slightly from standard-fast mode. Figure 23 describes this in further detail. Initially, the bus begins running in standard-fast mode. The master generates a start condition and sends the 8-bit Hs master code (00001XXX) to the DAC081C081. Next, the DAC081C081 responds with a NACK. Once the SCL line has been pulled to a high level, the master switches to Hs-mode by increasing the bus speed and generating a repeated start condition (driving SDA low while SCL is pulled high). At this point, the master sends the slave address to the DAC081C081, and communication continues as shown above in the "basic operation" diagram (see Figure 22). When the master generates a repeated start condition while in Hs-mode, the bus stays in Hs-mode awaiting the slave address from the master. The bus continues to run in Hs-mode until a stop condition is generated by the master. When the master generates a stop condition on the bus, the bus must be started in standard-fast mode again before increasing the bus speed and switching to Hs-mode. SDA NACK MSB 8-ELW 0DVWHU FRGH ³00001[[[´ 7-bit Slave Address Not-Acknowledge from the Device 1 SCL 2 6 5 7 8 9 1 2 Repeated START START Standard-Fast Mode Hs-Mode Figure 23. Beginning Hs-Mode Communication 8.5.5 I2C Slave (Hardware) Address The DAC has a seven-bit I2C slave address. For the VSSOP-8 version of the DAC, this address is configured by the ADR0 and ADR1 address selection inputs. For the DAC081C081, the address is configured by the ADR0 address selection input. ADR0 and ADR1 can be grounded, left floating, or tied to VA. If desired, the address selection inputs can be set to VA/2 rather than left floating. The state of these inputs sets the address the DAC responds to on the I2C bus (see Table 1). In addition to the selectable slave address, there is also a broadcast address (1001000) for all DAC081C081s and DAC081C085s on the 2-wire bus. When the bus is addressed by the broadcast address, all the DAC081C081's and DAC081C085's will respond and update synchronously. Figure 24 and Figure 25 describe how the master device should address the DAC through the I2C-compatible interface. Keep in mind that the address selection inputs (ADR0 and ADR1) are only sampled until the DAC is correctly addressed with a non-broadcast address. At this point, the ADR0 and ADR1 inputs TRI-STATE and the slave address is locked. Changes to ADR0 and ADR1 will not update the selected slave address until the device is power-cycled. Table 1. Slave Addresses SLAVE ADDRESS [A6 - A0] (1) 20 DAC101C081 (SOT & WSON) (1) DAC101C085 (VSSOP-8) ADR1 ADR0 ADR0 0001100, 1000110 Floating Floating Floating 0001101, 1000110 Floating GND GND Pin-compatible alternatives to the DAC101C081 options are available with additional address options. Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Programming (continued) Table 1. Slave Addresses (continued) DAC101C081 (SOT & WSON) (1) DAC101C085 (VSSOP-8) SLAVE ADDRESS [A6 - A0] ADR1 ADR0 ADR0 0001110, 1000111 Floating VA VA 0001000, 1000100 GND Floating — 0001001, 1000100 GND GND — 0001010, 1000101 GND VA — 1001100, 1100110 VA Floating — 1001101, 1100110 VA GND — 1001110, 1100111 VA VA — 1001000, 1100100 Broadcast Address 8.5.6 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 the master. The master then sends out the upper data byte. The DAC responds by sending an ACK to the master. Next, the master sends the lower data byte to the DAC. The DAC responds by sending an ACK again. At this point, the master either sends the upper byte of the next data word to be converted by the DAC, generates a Stop condition to end communication, or generates a repeated start condition to begin communication with another device on the bus. Until generating a stop condition, the master can continuously write the upper and lower data bytes to the DAC register. This allows for a maximum DAC conversion rate of 188.9 kilo-conversions per second in Hs-mode. 1 9 1 9 1 9 SCL SDA A6 Start by Master A5 A4 A3 A2 A1 A0 R/W 0 ACK by DAC081C081 Frame 1 Address Byte from Master 0 PD1 PD0 D11 D10 D9 Frame 2 Data Byte from Master D7 ACK by DAC081C081 D8 D6 D5 D4 D3 D2 D1 D0 ACK Stop by by Master DAC081C081 Frame 3 Data Byte from Master Repeat Frames 2 and 3 for Continuous Mode Figure 24. Typical Write to the DAC Register 8.5.7 Reading from the DAC Register To read from the DAC register, the master addresses the part with the correct slave address (A6-A0) and writes a one to the read/write bit. If addressed correctly, the DAC returns an ACK to the master. Next, the DAC sends out the upper data byte. The master responds by sending an ACK to the DAC to indicate that it wants to receive another data byte. Then the DAC sends the lower data byte to the master. Assuming only one 16-bit data word is read, the master sends a NACK after receiving the lower data byte. At this point, the master either generates a stop condition to end communication, or a repeated start condition to begin communication with another device on the bus. 1 9 1 9 1 9 SCL SDA A6 A5 A4 A3 A2 A1 Start by Master Frame 1 Address Byte from Master A0 R/W 0 ACK by DAC081C081 0 PD1 PD0 D11 D10 D9 Frame 2 Data Byte from DAC081C081 D8 D7 D6 D5 ACK by Master D4 D3 D2 Frame 3 Data Byte from DAC081C081 D1 D0 NACK by Master Stop by Master Figure 25. Typical Read from the DAC Register Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 21 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 8.6 Registers 8.6.1 DAC Register The DAC register, Figure 26, 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 the shift register are the data bits. The data format is straight binary (MSB first, LSB last), with twelve 0's corresponding to an output of 0V and twelve 1's corresponding to a full-scale output of VA – 1 LSB. When writing to the DAC Register, VOUT will update on the rising edge of the ACK following the lower data byte. LSB MSB X X PD1 PD0 D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 0 DATA BITS 0 0 1 1 0 1 0 1 Normal Operation. 2.5 kÖ to GND. 100 kÖ to GND. High Impedance. Power-Down Modes Figure 26. DAC Register Contents 22 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 9.1 Application Information 9.1.1 Bipolar Operation The DAC081C081 is designed for single-supply operation and thus has a unipolar output. However, a bipolar output may be obtained with the circuit in Figure 27. This circuit will provide an output voltage range of ±5 Volts. A rail-to-rail amplifier should be used if the amplifier supplies are limited to ±5 V. 10 pF R2 +5V R1 +5V 10 PF + - 0.1 PF ±5V + DAC081C081 SDA -5V VOUT SCL Figure 27. Bipolar Operation The output voltage of this circuit for any code is found to be VO = (VA × (D / 256) × ((R1 + R2) / R1) – VA × R2 / R1) where • D is the input code in decimal form. (2) With VA = 5V and R1 = R2, VO = (10 × D / 256) – 5 V (3) A list of rail-to-rail amplifiers suitable for this application are indicated in Table 2. Table 2. Some Rail-to-Rail Amplifiers AMP PKGS TYP VOS LMP7701 SOT23-5 37 uV LMV841 SC70-5 50 uV 1 mA LMC7111 SOT23-5 0.9 mV 25 µA LM7301 SO-8 SOT23-5 0.03 mV 620 µA LM8261 SOT23-5 0.7 mV 1 mA Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 TYP ISUPPLY 0.79 mA Submit Documentation Feedback 23 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 9.1.2 DSP/Microprocessor Interfacing Interfacing the DAC081C081 to microprocessors and DSPs is quite simple. The following guidelines are offered to simplify the design process. 9.1.2.1 Interfacing to the 2-Wire Bus Figure 28 shows a microcontroller interfacing to the DAC081C081 through the 2-wire bus. Pullup resistors (Rp) should be chosen to create an appropriate bus rise time and to limit the current that will be sunk by the opendrain outputs of the devices on the bus. Please refer to the I2C Specification for further details. Typical pullup values to use in standard-fast mode bus applications are 2 kΩ to 10 kΩ. SCL and SDA series resisters (RS) near the DAC081C081 are optional. If high-voltage spikes are expected on the 2-wire bus, series resistors should be used to filter the voltage on SDA and SCL. The value of the series resistance must be picked to ensure the VIL threshold can be achieved. If used, RS is typically 51 Ω. DAC081C081/5 10 PF VREF 4.7 PF VA 0.1 PF Regulated Supply RP RP VDD PController R S* SDA SDA SCL SCL R S* ADC081C021 SDA SCL I2C Device SDA SCL *NOTE: RS is optional. Figure 28. Serial Interface Connection Diagram 9.1.2.2 Interfacing to a Hs-mode Bus Interfacing to a Hs-mode bus is very similar to interfacing to a standard-fast mode bus. In Hs-mode, the specified rise time of SCL is shortened. To create a faster rise time, the master device (microcontroller) can drive the SCL bus high and low. In other words, the microcontroller can drive the line high rather than leaving it to the pullup resistor. It is also possible to decrease the value of the pullup resistors or increase the pullup current to meet the tighter timing specs. Please refer to the I2C Specification for further details. 24 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 9.2 Typical Application 2 VA 4 SDA 1 VOUT +5 120pF +5 3 + 5 SC L 6 ADR0 3 1uF 5 1 A2 4 LM4132-3.3 4 5 3 2 .1uF DAC081C081CIMK - 180 .2uF 2 +5 +3.3 10 VA 9 VIO 100K 470pF 2 +IN 1 VREF ADC161S626 AV = 100 2.02K 3 -IN 8 SCLK 7 DOUT 6 /CS 4, 5 +5 .2uF 100K 3 - 5 1 A1 Pressure Sensor 0.2mV/Volt/PSI 4 + 180 470pF 2 A1 and A2 = LMP7701 Figure 29. Pressure Sensor Gain Adjust 9.2.1 Design Requirements A positive supply only data acquisition system capable of digitizing a pressure sensor output. In addition to digitizing the pressure sensor output, the system designer can use the DAC081C081 to correct for gain errors in the pressure sensor output by adjusting the bias voltage to the bridge pressure sensor. 9.2.2 Detailed Design Procedure As shown in Equation 4, the output of the pressure sensor is relative to the imbalance of the resistive bridge times the output of the DAC081C081, thus providing the desired gain correction. Pressure Sensor Output = (DAC_Output × [(R2 / (R1 + R2) – (R4 / (R3 + R4)] (4) Likewise for the ADC161S626, Equation 5 shows that the ADC output is function of the pressure sensor output times relative to the ratio of the ADC input divided by the DAC081C081 output voltage. ADC161S626 Output = (Pressure Sensor Output × 100 /(2 × VREF) ) × 216 (5) 9.2.3 Application Curve Figure 30. INL vs Input Code Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 25 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 10 Power Supply Recommendations 10.1 Using References as Power Supplies While the simplicity of the DAC081C081 implies ease of use, it is important to recognize that the path from the reference input (VA for the DAC081C081 and VREF for the DAC081C085) to VOUT will have essentially zero Power Supply Rejection Ratio (PSRR). Therefore, it is necessary to provide a noise-free supply voltage to the reference. In order to use the full dynamic range of the DAC081C085, the supply pin (VA) and VREF can be connected together and share the same supply voltage. Since the DAC081C081 consumes very little power, a reference source may be used as the supply voltage. The advantages of using a reference source over a voltage regulator are accuracy and stability. Some low noise regulators can also be used. Listed below are a few reference and power supply options for the DAC081C081. When using the DAC081C081, it is important to treat the analog supply (VA) as the reference. 10.1.1 LM4132 The LM4132, with its 0.05% accuracy over temperature, is a good choice as a reference source for the DAC081C081. The 4.096-V version is useful if a 0 to 4.095-V output range is desirable or acceptable. Bypassing the LM4132 VIN pin with a 0.1-µF capacitor and the VOUT pin with a 2.2-µF capacitor will improve stability and reduce output noise. The LM4132 comes in a space-saving 5-pin SOT23. Input Voltage LM4132-4.1 C3 0.1 PF C2 2.2 PF C1 0.1 PF VA VREF DAC081C081/5 VOUT = 0V to 4.092V SDA SCL Figure 31. The LM4132 as a Power Supply 10.1.2 LM4050 Available with accuracy of 0.44%, the LM4050 shunt reference is also a good choice as a reference for the DAC081C081. It is available in 4.096-V and 5-V versions and comes in a space-saving 3-pin SOT23. Input Voltage R IDAC VZ IZ 0.1 PF 0.47 PF LM4050-4.1 or LM4050-5.0 VA VREF DAC081C081/5 VOUT = 0V to 5V SDA SCL Figure 32. The LM4050 as a Power Supply 26 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Using References as Power Supplies (continued) The minimum resistor value in the circuit of Figure 32 must be chosen such that the maximum current through the LM4050 does not exceed its 15-mA rating. The conditions for maximum current include the input voltage at its maximum, the LM4050 voltage at its minimum, and the DAC081C081 drawing zero current. The maximum resistor value must allow the LM4050 to draw more than its minimum current for regulation plus the maximum DAC081C081 current in full operation. The conditions for minimum current include the input voltage at its minimum, the LM4050 voltage at its maximum, the resistor value at its maximum due to tolerance, and the DAC081C081 draws its maximum current. These conditions can be summarized as R(min) = ( VIN(max) − VZ(min) ) /IZ(max) (6) and R(max) = ( VIN(min) − VZ(max) ) / ( (IDAC(max) + IZ(min) ) where • • • • VZ(min) and VZ(max) are the nominal LM4050 output voltages ± the LM4050 output tolerance over temperature, IZ(max) is the maximum allowable current through the LM4050, IZ(min) is the minimum current required by the LM4050 for proper regulation, and IDAC(max) is the maximum DAC081C081 supply current. (7) 10.1.3 LP3985 The LP3985 is a low noise, ultra low dropout voltage regulator with a 3% accuracy over temperature. It is a good choice for applications that do not require a precision reference for the DAC081C081. It comes in 3-V, 3.3-V and 5-V versions, among others, and sports a low 30-µV noise specification at low frequencies. Since low frequency noise is relatively difficult to filter, this specification could be important for some applications. The LP3985 comes in a space-saving 5-pin SOT-23 and 5-bump DSBGA packages. Input Voltage LP3985 0.1 PF 1 PF 0.01 PF 0.1 PF VA VREF DAC081C081/5 VOUT = 0V to 5V SDA SCL Figure 33. Using the LP3985 Regulator An input capacitance of 1 µF without any ESR requirement is required at the LP3985 input, while a 1-µF ceramic capacitor with an ESR requirement of 5 mΩ to 500 mΩ is required at the output. Careful interpretation and understanding of the capacitor specification is required to ensure correct device operation. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 27 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com Using References as Power Supplies (continued) 10.1.4 LP2980 The LP2980 is an ultra low dropout regulator with a 0.5% or 1.0% accuracy over temperature, depending upon grade. It is available in 3-V, 3.3-V and 5-V versions, among others. Input Voltage VIN VOUT LP2980 ON /OFF 1 PF 0.1 PF VA VREF DAC081C081/5 VOUT = 0V to 5V SDA SCL Figure 34. Using the LP2980 Regulator Like any low dropout regulator, the LP2980 requires an output capacitor for loop stability. This output capacitor must be at least 1 µF over temperature, but values of 2.2 µF or more will provide even better performance. The ESR of this capacitor should be within the range specified in the LP2980 data sheet. Surface-mount solid tantalum capacitors offer a good combination of small size and ESR. Ceramic capacitors are attractive due to their small size but generally have ESR values that are too low for use with the LP2980. Aluminum electrolytic capacitors are typically not a good choice due to their large size and have ESR values that may be too high at low temperatures. 28 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 11 Layout 11.1 Layout Guidelines For best accuracy and minimum noise, the printed-circuit-board containing the DAC081C081 should have separate analog and digital areas. The areas are defined by the locations of the analog and digital power planes. Both of these planes should be located on the same board layer. There should be a single ground plane. A single ground plane is preferred if digital return current does not flow through the analog ground area. Frequently a single ground plane design will use a fencing technique to prevent the mixing of analog and digital ground current. Separate ground planes should only be used when the fencing technique is inadequate. The separate ground planes must be connected in one place, preferably near the DAC081C081. Special care is required to ensure that digital signals with fast edge rates do not pass over split ground planes. They must always have a continuous return path below their traces. The DAC081C081 power supply should be bypassed with a 4.7-µF and a 0.1-µF capacitor as close as possible to the device with the 0.1 µF right at the device supply pin. The 4.7-µF capacitor should be a tantalum type and the 0.1-µF capacitor should be a low ESL, low ESR type. The power supply for the DAC081C081 should only be used for analog circuits. Avoid crossover of analog and digital signals and keep the clock and data lines on the component side of the board. These clock and data lines should have controlled impedances. 11.2 Layout Example VOUT ADR0 SOT VA SCL C1 SDA GND Figure 35. Typical Layout Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 29 DAC081C081, DAC081C085 SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 www.ti.com 12 Device and Documentation Support 12.1 Device Support 12.1.1 Development Support For development support, see the following: • 12-Bit Micro Power Digital-to-Analog Converter with an I2C-Compatible Interface, DAC121C081 • 12-Bit Micro Pwr DAC w/ I2C-Compatible Interface & External Reference, DAC121C085 • 10-Bit Micro Power Digital-to-Analog Converter with an I2C-Compatible Interface, DAC101C081 • 10-Bit Micro Pwr DAC w/ I2C-Compatible Interface & External Reference, DAC101C085 12.1.2 Device Nomenclature 12.1.2.1 Specification Definitions DIFFERENTIAL NON-LINEARITY (DNL) is the measure of the maximum deviation from the ideal step size of 1 LSB, which is VREF / 256 = VA / 256. DIGITAL FEEDTHROUGH is a measure of the energy injected into the analog output of the DAC from the digital inputs when the DAC output is not updated. It is measured with a full-scale code change on the data bus. FULL-SCALE ERROR is the difference between the actual output voltage with a full scale code (FFFh) loaded into the DAC and the value of VA x 255 / 256. GAIN ERROR is the deviation from the ideal slope of the transfer function. It can be calculated from Zero and Full-Scale Errors as GE = FSE - ZE, where GE is Gain error, FSE is Full-Scale Error and ZE is Zero Error. GLITCH IMPULSE is the energy injected into the analog output when the input code to the DAC register changes. It is specified as the area of the glitch in nanovolt-seconds. INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line through the input to output transfer function. The deviation of any given code from this straight line is measured from the center of that code value. The end point method is used. INL for this product is specified over a limited range, per the Electrical Tables. LEAST SIGNIFICANT BIT (LSB) is the bit that has the smallest value or weight of all bits in a word. This value is LSB = VREF / 2n where VREF is the supply voltage for this product, and "n" is the DAC resolution in bits, which is 8 for the DAC081C081. MAXIMUM LOAD CAPACITANCE is the maximum capacitance that can be driven by the DAC with output stability maintained. MONOTONICITY is the condition of being monotonic, where the DAC has an output that never decreases when the input code increases. MOST SIGNIFICANT BIT (MSB) is the bit that has the largest value or weight of all bits in a word. Its value is 1/2 of VA. MULTIPLYING BANDWIDTH is the frequency at which the output amplitude falls 3dB below the input sine wave on VREFIN with a full-scale code loaded into the DAC. POWER EFFICIENCY is the ratio of the output current to the total supply current. The output current comes from the power supply. The difference between the supply and output currents is the power consumed by the device without a load. SETTLING TIME is the time for the output to settle to within 1/2 LSB of the final value after the input code is updated. TOTAL HARMONIC DISTORTION (THD) is the measure of the harmonics present at the output of the DACs with an ideal sine wave applied to VREFIN. THD is measured in dB. WAKE-UP TIME is the time for the output to exit power-down mode. This time is measured from the rising edge of SCL during the ACK bit of the lower data byte to the time the output voltage deviates from the 30 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 DAC081C081, DAC081C085 www.ti.com SNAS449E – FEBRUARY 2008 – REVISED JANUARY 2016 Device Support (continued) power-down voltage of 0V. ZERO CODE ERROR is the output error, or voltage, present at the DAC output after a code of 000h has been entered. 12.2 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 3. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY DAC081C081 Click here Click here Click here Click here Click here DAC081C085 Click here Click here Click here Click here Click here 12.3 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 12.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 12.5 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 12.6 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: DAC081C081 DAC081C085 Submit Documentation Feedback 31 PACKAGE OPTION ADDENDUM www.ti.com 8-Oct-2015 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) DAC081C081CIMK/NOPB ACTIVE SOT DDC 6 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 125 X86C DAC081C081CIMKX/NOPB ACTIVE SOT DDC 6 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 125 X86C DAC081C081CISD/NOPB ACTIVE WSON NGF 6 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X89 DAC081C081CISDX/NOPB ACTIVE WSON NGF 6 4500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X89 DAC081C085CIMM/NOPB ACTIVE VSSOP DGK 8 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X92C DAC081C085CIMMX/NOPB ACTIVE VSSOP DGK 8 3500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 X92C (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 8-Oct-2015 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 8-Oct-2015 TAPE AND REEL INFORMATION *All dimensions are nominal Device DAC081C081CIMK/NOPB DAC081C081CIMKX/NOP B Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant SOT DDC 6 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 SOT DDC 6 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 NGF 6 1000 178.0 12.4 2.8 2.5 1.0 8.0 12.0 Q1 DAC081C081CISDX/NOP B DAC081C081CISD/NOPB WSON WSON NGF 6 4500 330.0 12.4 2.8 2.5 1.0 8.0 12.0 Q1 DAC081C085CIMM/NOP B VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 DAC081C085CIMMX/NO PB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 8-Oct-2015 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DAC081C081CIMK/NOPB SOT DDC 6 1000 210.0 185.0 35.0 SOT DDC 6 3000 210.0 185.0 35.0 DAC081C081CIMKX/NOP B WSON NGF 6 1000 210.0 185.0 35.0 DAC081C081CISDX/NOP B DAC081C081CISD/NOPB WSON NGF 6 4500 367.0 367.0 35.0 DAC081C085CIMM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 VSSOP DGK 8 3500 367.0 367.0 35.0 DAC081C085CIMMX/NOP B Pack Materials-Page 2 MECHANICAL DATA NGF0006A www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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