Order Now Product Folder Support & Community Tools & Software Technical Documents DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 DACx0504 Quad, 16-, 14-Bit, SPI Voltage Output DACs With Internal Reference 1 Features 3 Description • The DACx0504 is a pin-compatible family of lowpower, four-channel, buffered voltage-output, digitalto-analog converter (DAC) with 16- and 14-bit resolution. The DACx0504 includes a 2.5-V, 5ppm/°C internal reference, eliminating the need for an external precision reference in most applications. A user-selectable gain configuration provides full-scale output voltages of 1.25 V (gain = ½), 2.5 V (gain = 1), or 5 V (gain = 2). This device operates from a single 2.7-V to 5.5-V supply, is specified monotonic, and provides high linearity of ±1 LSB INL. 1 • • • • • • • Performance – INL: ±1 LSB Maximum at 16-Bit Resolution – TUE: ±0.14% of FSR Maximum Integrated 2.5 V Precision Internal Reference – Initial Accuracy: ±5 mV, Maximum – Low Drift: 5 ppm/°C, Typical High Drive Capability: 20 mA With 0.5 V From Supply Rails Flexible Output Configuration – User Selectable Gain: 2, 1 or ½ – Reset to Zero Scale or Midscale Wide Operating Range – Power Supply: 2.7 V to 5.5 V – Temperature: –40˚C to +125˚C 50-MHz, SPI-Compatible Serial Interface – 4-Wire Mode, 1.7 V to 5.5 V Operation – Daisy-Chain Operation – CRC Error Check Low Power: 0.7 mA/Channel at 5.5 V Small Package: 3-mm × 3-mm, 16-Pin WQFN Communication to the DACx0504 is performed through a 4-wire serial interface that operates at clock rates of up to 50 MHz. The VIO pin enables serial interface operation from 1.7 V to 5.5 V. The DACx0504 flexible interface enables operation with a wide range of industry-standard microprocessors and microcontrollers. The DACx0504 incorporates a power-on-reset circuit that powers up and maintains the DAC outputs at either zero scale or midscale until a valid code is written to the device. This device consumes low current of 0.7 mA/channel at 5.5 V, making it suitable for battery-operated equipment. A per-channel powerdown feature reduces the device current consumption to 15 µA. 2 Applications • • • • The DACx0504 is characterized for operation over the temperature range of –40°C to +125°C, and is available in a small, 3-mm × 3-mm, QFN package. Optical Networking Wireless Infrastructure Industrial Automation Data Acquisition Systems Device Information(1) PART NUMBER DACx0504(2) PACKAGE WQFN (16) BODY SIZE (NOM) 3.00 mm × 3.00 mm (1) For all available packages, see the package option addendum at the end of the data sheet. (2) DAC80504 Product Preview Simplified Block Diagram VIO VDD REFDIV REF GAIN Internal Reference DACx0504 ÷1 or ÷2 GAIN ×1 or ×2 SCLK DAC Buffer CS LDAC Interface Logic SDI SDO/ALARM DAC Register DAC OUT0 BUF Channel 0 Channel 1 OUT1 Channel 2 OUT2 Channel 3 OUT3 Power On Reset RSTSEL Power Down Logic Resistive Network GND Copyright © 2017, Texas Instruments Incorporated 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. UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA. DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Device Comparison Table..................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 5 7.1 7.2 7.3 7.4 7.5 7.6 5 5 5 6 6 9 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 18 8.1 8.2 8.3 8.4 Overview ................................................................. Functional Block Diagram ....................................... Feature Description................................................. Device Functional Modes........................................ 18 18 19 23 8.5 Programming........................................................... 26 8.6 Register Map........................................................... 28 9 Application and Implementation ........................ 34 9.1 Application Information............................................ 34 9.2 Typical Application .................................................. 36 10 Power Supply Recommendations ..................... 38 11 Layout................................................................... 39 11.1 Layout Guidelines ................................................. 39 11.2 Layout Example .................................................... 39 12 Device and Documentation Support ................. 40 12.1 12.2 12.3 12.4 12.5 12.6 Related Links ........................................................ Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 40 40 40 40 40 40 13 Mechanical, Packaging, and Orderable Information ........................................................... 40 4 Revision History Changes from Original (August 2017) to Revision A • 2 Page Changed from Advance Information to Mixed Status............................................................................................................. 1 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 5 Device Comparison Table (1) DEVICE RESOLUTION REFERENCE DAC80504 (1) 16-Bit Internal (default) or External DAC70504 14-Bit Internal (default) or External Product Preview Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 3 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 6 Pin Configuration and Functions SDI SCLK 13 3 10 REFDIV 4 9 RSTSEL 7 8 GAIN OUT2 14 LDAC VDD OUT1 SDO/ALARM 11 Thermal Pad 6 2 15 CS GND OUT0 VIO 12 5 1 OUT3 REF 16 RTE Package 16-Pin WQFN Top View Not to scale Pin Functions PIN NAME NO. TYPE DESCRIPTION REF 1 I/O When using internal reference, this is the reference output voltage pin (default). When using an external reference, this is the reference input pin to the device. OUT0 2 O Analog output voltage from DAC 0. OUT1 3 O Analog output voltage from DAC 1. OUT2 4 O Analog output voltage from DAC 2. OUT3 5 O Analog output voltage from DAC 3. GND 6 GND Ground reference point for all circuitry on the device. VDD 7 PWR Analog supply voltage (2.7 V to 5.5 V). GAIN 8 I Sets the gain configuration after a power-up or reset event. When tied to GND, the initial buffer amplifier gain for all four channels is set to 1. When tied to VIO the initial buffer amplifier gain is 2. Changing the state of this pin after power-up does not affect the device operation. RSTSEL 9 I Reset select pin. When tied to GND all four DACs reset to zero scale. When connected to VIO all four DACs reset to midscale. REFDIV 10 I Sets the reference divider configuration after a power-up or reset event. When tied to GND, the reference voltage is not divided down. When tied to VIO the reference voltage is divided by 2. Changing the state of this pin after power-up does not affect the device operation. LDAC 11 I A high-to-low transition on the LDAC pin causes the DAC outputs of those channels configured in synchronous mode to update simultaneously. The pin can be tied permanently to GND. CS 12 I Active low serial data enable. This input is the frame synchronization signal for the serial data. When the signal goes low, it enables the serial interface input shift register. SCLK 13 I Serial interface clock. SDI 14 I Serial interface data input. Data are clocked into the input shift register on each falling edge of the SCLK pin. Serial interface data output (default). The SDO pin is in high impedance when CS pin is high. Data are clocked out of the input shift register on either rising or falling edges of the SCLK pin as specified by the FSDO bit. Alternatively the pin can be configured as an ALARM open-drain output to indicate a CRC or reference alarm event. If configured as ALARM a 10 kΩ, pull-up resistor to VIO is required. SDO/ALARM 15 O VIO 16 PWR IO supply voltage (1.7 V to 5.5 V). This pin sets the I/O operating voltage for the serial interface. Thermal Pad – – The thermal pad is located on the bottom-side of the QFN package. The thermal pad should be connected to any internal PCB ground plane using multiple vias for good thermal performance. 4 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) Suppy voltage Pin voltage Input current Temperature (1) (1) MIN MAX VDD to GND –0.3 6 UNIT VIO to GND –0.3 6 DAC outputs to GND –0.3 VDD + 0.3 REF to GND –0.3 VDD + 0.3 GAIN, LDAC, REFDIV, RSTSEL, SCLK, SDI, SDO/ALARM and CS to GND –0.3 VIO + 0.3 Input current to any pin except supply pins –10 10 Operating free-air, TA –40 125 Junction, TJ –40 150 Storage, Tstg –60 150 V V mA °C 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. 7.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±3000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±1000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT POWER SUPPLY VDD Analog supply voltage 2.7 5.5 VIO IO supply voltage 1.7 5.5 0 VIO Reference divider disabled 1.2 (VDD – 0.2)/2 Reference divider enabled 2.4 VDD – 0.2 Reference divider disabled 1.2 VDD/2 Reference divider enabled 2.4 VDD –40 125 V DIGITAL INPUTS Digital input voltage V REFERENCE INPUT VDD = 2.7 V to 3.3 V VREFIN VDD = 3.3 V to 5.5 V V TEMPERATURE TA Operating free-air temperature Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 °C 5 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 7.4 Thermal Information DACx0504 THERMAL METRIC (1) RTE (WQFN) UNIT 16 PINS RθJA Junction-to-ambient thermal resistance 33.3 °C/W RθJC(top) Junction-to-case (top) thermal resistance 29.5 °C/W RθJB Junction-to-board thermal resistance 7.3 °C/W ψJT Junction-to-top characterization parameter 0.2 °C/W ψJB Junction-to-board characterization parameter 7.4 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance 0.9 °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. 7.5 Electrical Characteristics all minimum and maximum specifications at VDD= 2.7 V to 5.5 V, VIO = 1.7 V to 5.5 V, VREFIN = 1.25 V to 5.5 V, RLOAD = 2 kΩ to GND, CLOAD = 200 pF to GND, digital inputs at VIO or GND, and TA = –40°C to +125°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT STATIC PERFORMANCE (1) DAC80504 16 DAC70504 14 Resolution INL DNL Bits DAC80504 ±0.5 ±1 DAC70504 ±0.5 ±1 DAC80504. Specified 16-bit monotonic ±0.5 ±1 DAC70504. Specified 14-bit monotonic ±0.5 ±1 ±0.06 ±0.14 ±0.1 ±0.2 ±0.75 ±1.5 mV 0.5 1.5 mV ±0.075 ±0.14 ±0.1 ±0.22 ±0.05 ±0.14 Integral nonlinearity LSB Differential nonlinearity LSB Gain = 1 and Gain = 2 TUE Total unadjusted error %FSR Gain = ½ Offset error Zero-code error DAC code = zero scale Gain = 1 and Gain = 2 Full-scale error % FSR Gain = ½ Gain error % FSR Offset error drift ±1 Zero-code error drift ±2 µV/°C Full-scale error drift ±2 ppm of FSR/°C ±1 ppm of FSR/°C 20 ppm of FSR Gain error drift Output voltage drift over time TA = 25°C, DAC code = midscale, 1600 hours µV/°C OUTPUT CHARACTERISTICS Voltage range Gain = 2 (BUFF-GAIN = 1, REF-DIV = 0) 0 Gain = 1 (BUFF-GAIN = 1, REF-DIV = 1) 0 VREF Gain = ½ (BUFF-GAIN = 0, REF-DIV = 1) 0 ½ × VREF to GND or VDD (unloaded) Output voltage headroom Short circuit current (2) Load regulation Maximum capacitive load (3) to GND or VDD (–5 mA ≤ IOUT ≤ 5 mA) 2 × VREF 0.004 0.15 V to GND or VDD (–10 mA ≤ IOUT ≤ 10 mA) 0.3 to GND or VDD (–20 mA ≤ IOUT ≤ 20 mA) 0.5 DAC code = full scale, output shorted to GND 35 DAC code = zero scale, output shorted to VDD 30 mA DAC code = midscale, -10 mA ≤ IOUT ≤ 10 mA 85 0 2 RLOAD = 2 kΩ 0 10 DAC code = midscale nF 0.085 Ω DAC code at GND or VDD (2) (3) 6 µV/mA RLOAD = ∞ DC output impedance (1) V 15 Static performance specified with DAC outputs unloaded for all gain options, unless otherwise noted. End point fit between codes. 16bit: Code 256 to 65280, 14-bit: Code 128 to 16127 Temporary overload condition protection. Junction temperature can be exceeded during current limit. Operation above the specified maximum junction temperature may impair device reliability. Specified by design and characterization. Not tested during production. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Electrical Characteristics (continued) all minimum and maximum specifications at VDD= 2.7 V to 5.5 V, VIO = 1.7 V to 5.5 V, VREFIN = 1.25 V to 5.5 V, RLOAD = 2 kΩ to GND, CLOAD = 200 pF to GND, digital inputs at VIO or GND, and TA = –40°C to +125°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DYNAMIC PERFORMANCE Output voltage settling time ¼ to ¾ scale and ¾ to ¼ scale settling time to ±2 LSB, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 Slew rate VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 1.8 V/µs Power-up time DACx-PWDWN 1 to 0 transition, DAC code = full scale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 (4) 12 µs Power-up glitch magnitude DAC code = zero scale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2. CLOAD = 50 pF 25 mV Output noise 0.1 Hz to 10 Hz, DAC code = midscale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 14 µVPP 1 kHz, DAC code = midscale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 78 10 kHz, DAC code = midscale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 2 74 1 kHz, DAC code = full scale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 1 55 10 kHz, DAC code = full scale, VDD = 5.5 V, VREFIN = 2.5 V, Gain = 1 50 AC PSRR DAC code = midscale, frequency = 60 Hz, amplitude = 200 mVPP superimposed on VDD 85 dB DC PSRR DAC code = midscale, VDD = 5 V ± 10% 10 µV/V Code change glitch impulse 1 LSB change around major carrier 4 nV-s Channel-to-channel ac crosstalk DAC code = midscale. Code 32 to full-scale swing on adjacent channel 0.2 nV-s Measured channel at midscale. Adjacent channel at full scale. 10 Measured channel at midscale. All other channels at full scale. 80 DAC code = midscale. fSCLK = 1 MHz, SDO disabled 0.1 nV-s 5 µs Output noise density nV/√Hz Channel-to-channel dc crosstalk Digital feedthrough µV EXTERNAL REFERENCE INPUT Reference input current VREFIN = 2.5 V Reference input impedance Reference input capacitance 25 µA 100 kΩ 5 pF INTERNAL REFERENCE VREFOUT Reference output voltage TA = 25°C 2.495 Reference output drift Reference output impedance Reference output noise 0.1 Hz to 10 Hz Reference output noise density 10 kHz, REFLOAD = 10 nF Reference load current Reference load regulation 2.505 5 8 V ppm/°C 0.1 Ω 15 µVPP 130 nV/√Hz ±5 mA Source and sink 100 µV/mA 20 µV/V TA = 25°C, 1600 hours 4.8 ppm First cycle 190 Reference line regulation Reference output drift over time 2.5 Reference thermal hysteresis ppm Additional cycle 18 DIGITAL INPUTS VIH High-level input voltage VIL Low-level input voltage 0.7 × VIO V 0.3 × VIO Input current Input pin capacitance V ±2 µA 2 pF DIGITAL OUTPUTS VOH High-level output voltage ILOAD = 0.2 mA VOL Low-level output voltage ILOAD = -0.2 mA VIO – 0.4 V 0.4 Output pin capacitance (4) 4 V pF Time to exit DAC power-down mode. Measured from CS rising edge to 90% of DAC final value. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 7 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Electrical Characteristics (continued) all minimum and maximum specifications at VDD= 2.7 V to 5.5 V, VIO = 1.7 V to 5.5 V, VREFIN = 1.25 V to 5.5 V, RLOAD = 2 kΩ to GND, CLOAD = 200 pF to GND, digital inputs at VIO or GND, and TA = –40°C to +125°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Active mode. Internal reference enabled. Gain = 1. DAC code = full scale. Outputs unloaded. SPI static 2.8 3.6 Active mode. Internal reference disabled. Gain = 1. DAC code = full scale. Outputs unloaded. SPI static 2.3 3 Power-down 15 30 µA 2 3 µA POWER SUPPLY REQUIREMENTS mA IDD VDD supply current IIO VIO supply current 8 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 7.6 Typical Characteristics 1 1 0.8 0.8 0.6 0.6 0.4 0.4 DNL (LSB) INL (LSB) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 0.2 0 -0.2 -0.4 0 -0.2 -0.4 OUT0 OUT1 OUT2 OUT3 -0.6 -0.8 OUT0 OUT1 OUT2 OUT3 -0.6 -0.8 -1 -1 0 2048 4096 6144 8192 10240 12288 14336 16384 Code D001 0 Figure 1. Integral Linearity Error vs Digital Input Code 1 0.105 0.8 0.07 0.035 0 -0.035 -0.07 OUT0 OUT1 OUT2 OUT3 -0.105 2048 4096 6144 8192 10240 12288 14336 16384 Code D002 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -1 -40 8192 10240 12288 14336 16384 Code D003 -25 -10 5 20 35 50 65 Temperature (qC) 80 95 110 125 D004 Figure 4. Integral Linearity Error vs Temperature 1 0.14 DNL Max DNL Min TUE Total Unadjusted Error (%FSR) 0.8 DNL Error Max-Min (LSB) 6144 INL Max INL Min Figure 3. Total Unadjusted Error vs Digital Input Code 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -40 4096 -0.8 -0.14 0 2048 Figure 2. Differential Linearity Error vs Digital Input Code 0.14 INL Error Max-Min (LSB) Total Unadjusted Error (%FSR) 0.2 -25 -10 5 20 35 50 65 Temperature (qC) 80 95 110 125 0.105 0.07 0.035 0 -0.035 -0.07 -0.105 -0.14 -40 -25 -10 D005 Figure 5. Differential Linearity Error vs Temperature 5 20 35 50 65 Temperature (qC) 80 95 110 125 D006 Figure 6. Total Unadjusted Error vs Temperature Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 9 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 1.5 1.5 Zero Code Error (mV) Offset Error (mV) 1 0.5 0 -0.5 1 0.5 -1 -1.5 -40 -25 -10 5 20 35 50 65 Temperature (qC) 80 95 0 -40 110 125 Figure 7. Offset Error vs Temperature 0.105 0.105 Full Scale Error (%FSR) 0.14 Gain Error (%FSR) 0.07 0.035 0 -0.035 -0.07 -0.105 -25 -10 5 20 35 50 65 Temperature (qC) 80 80 95 110 125 D008 0.035 0 -0.035 -0.07 95 -0.14 -40 110 125 -25 -10 5 D009 20 35 50 65 Temperature (qC) 80 95 110 125 D010 Figure 10. Full Scale Error vs Temperature 1 INL Max INL Min 0.8 DNL Max DNL Min 0.8 0.6 DNL Error Max-Min (LSB) INL Error Max-Min (LSB) 20 35 50 65 Temperature (qC) 0.07 Figure 9. Gain Error vs Temperature 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 3.1 3.5 3.9 4.3 VDD (V) 4.7 5.1 5.5 -1 2.7 3.1 D011 Gain = 1 3.5 3.9 4.3 VDD (V) 4.7 5.1 5.5 D012 Gain = 1 Figure 11. Integral Linearity Error vs Supply Voltage 10 5 -0.105 1 -1 2.7 -10 Figure 8. Zero Code Error vs Temperature 0.14 -0.14 -40 -25 D007 Figure 12. Differential Linearity Error vs Supply Voltage Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 1.5 REF-DIV = 1 REF-DIV = 0 0.105 REF-DIV = 1 REF-DIV = 0 1 0.07 Offset Error (mV) Total Unadjusted Error (%FSR) 0.14 0.035 0 -0.035 0.5 0 -0.5 -0.07 -1 -0.105 -0.14 2.7 3.1 3.5 3.9 4.3 VDD (V) 4.7 5.1 -1.5 2.7 5.5 Gain = 1 3.9 4.3 VDD (V) 4.7 5.1 5.5 D014 Figure 14. Offset Error vs Supply Voltage 1.5 0.14 REF-DIV = 1 REF-DIV = 0 1.25 REF-DIV = 1 REF-DIV = 0 0.105 0.07 Gain Error (%FSR) Zero Code Error (mV) 3.5 Gain = 1 Figure 13. Total Unadjusted Error vs Supply Voltage 1 0.75 0.5 0.035 0 -0.035 -0.07 0.25 0 2.7 -0.105 3.1 3.5 3.9 4.3 VDD (V) 4.7 5.1 -0.14 2.7 5.5 3.5 3.9 4.3 VDD (V) 4.7 5.1 5.5 D016 Gain = 1 Figure 15. Zero Code Error vs Supply Voltage Figure 16. Gain Error vs Supply Voltage 0.14 1 REF-DIV = 1 REF-DIV = 0 INL Max INL Min 0.8 INL Error Max-Min (LSB) 0.105 0.07 0.035 0 -0.035 -0.07 -0.105 -0.14 2.7 3.1 D015 Gain = 1 Full Scale Error (%FSR) 3.1 D013 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 3.1 3.5 3.9 4.3 VDD (V) 4.7 5.1 5.5 -1 1.25 2 D017 Gain = 1 2.75 3.5 VREFIN (V) 4.25 5 5.5 D018 Gain = 1 Figure 17. Full Scale Error vs Supply Voltage Figure 18. Integral Linearity Error vs Reference Voltage Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 11 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 1 0.14 DNL Error Max-Min (LSB) Total Unadjusted Error (%FSR) DNL Max DNL Min 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 1.25 2 2.75 3.5 VREFIN (V) 4.25 5 0.035 0 -0.035 -0.07 -0.105 2.75 3.5 VREFIN (V) 4.25 5 5.5 D020 Gain = 1 Figure 20. Total Unadjusted Error vs Reference Voltage 1.5 1.5 REF-DIV = 0 REF-DIV = 1 1 REF-DIV = 0 REF-DIV = 1 Zero Code Error (mV) 1.25 0.5 0 -0.5 -1 1 0.75 0.5 0.25 -1.5 1.25 2 2.75 3.5 VREFIN (V) 4.25 5 0 1.25 5.5 2.75 3.5 VREFIN (V) 4.25 5 5.5 D022 Gain = 1 Figure 21. Offset Error vs Reference Voltage Figure 22. Zero Code Error vs Reference Voltage 0.14 0.14 REF-DIV = 0 REF-DIV = 1 REF-DIV = 0 REF-DIV = 1 0.105 Full Scale Error (%FSR) 0.105 0.07 0.035 0 -0.035 -0.07 0.07 0.035 0 -0.035 -0.07 -0.105 -0.105 -0.14 1.25 2 D021 Gain = 1 Gain Error (%FSR) 2 D019 Figure 19. Differential Linearity Error vs Reference Voltage Offset Error (mV) 0.07 -0.14 1.25 5.5 Gain = 1 2 2.75 3.5 VREFIN (V) 4.25 5 5.5 -0.14 1.25 2 D023 Gain = 1 2.75 3.5 VREFIN (V) 4.25 5 5.5 D024 Gain = 1 Figure 23. Gain Error vs Reference Voltage 12 REF-DIV = 0 REF-DIV = 1 0.105 Figure 24. Full Scale Error vs Reference Voltage Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 3 3 3.2 3.2 2.8 2.8 2.4 2.4 2.5 1.5 1.5 IDD, Gain = 2 IIO, Gain = 2 1 IDD, Gain = 1 IIO, Gain = 1 0.5 1 0.5 0 0 2048 4096 6144 IDD (mA) 2 IIO (PA) 2 2 0.8 0.4 0.4 1.2 0 8192 10240 12288 14336 16384 Code D025 0 0 Gain = 1. External Reference = 2.5 V 3 4096 6144 0 8192 10240 12288 14336 16384 Code D026 Figure 26. Supply Current with Internal Reference vs Digital Input Code 3 3.6 3.6 3.2 3.2 2.8 2.8 2.4 2.4 2.5 1 IDD, Gain = 2 IIO, Gain = 2 1.5 IDD, Gain = 1 IIO, Gain = 1 1 0.5 0.5 1.5 0 -40 -25 -10 5 20 35 50 65 Temperature (qC) 80 95 IDD (mA) 2 IIO (PA) 2 2 2 0.8 IDD, Gain = 2 1.6 IIO, Gain = 2 IDD, Gain = 1 1.2 IIO, Gain = 1 0.8 0.4 0.4 1.6 1.2 0 110 125 0 -40 -25 -10 5 D027 Gain = 1. External Reference = 2.5 V 20 35 50 65 Temperature (qC) 80 95 IIO (PA) 2.5 IDD (mA) 2048 Gain = 1 Figure 25. Supply Current with External Reference vs Digital Input Code 0 110 125 D028 Gain = 1 Figure 27. Supply Current with External Reference vs Temperature 3 Figure 28. Supply Current with Internal Reference vs Temperature 3 2.5 3.6 3.6 3.2 3.2 2.8 2.8 2.4 2.4 2.5 1.5 1.5 1 1 IDD IIO 0.5 IDD (mA) 2 IIO (PA) 2 IDD (mA) 2 IDD, Gain = 2 1.6 IIO, Gain = 2 IDD, Gain = 1 1.2 IIO, Gain = 1 0.8 1.6 2 2 1.6 1.2 1.6 IDD IIO 1.2 0.8 0.8 0.4 0.4 IIO (PA) IDD (mA) 3.6 IIO (PA) 2.5 3.6 0.5 0 2.7 3.1 3.5 3.9 4.3 VDD (V) 4.7 5.1 0 5.5 0 2.7 3.1 D029 Gain = 1. External Reference = 2.5 V 3.5 3.9 4.3 VDD (V) 4.7 5.1 0 5.5 D030 Gain = 1 Figure 29. Supply Current with External Reference vs Supply Voltage Figure 30. Supply Current with Internal Reference vs Supply Voltage Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 13 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 1 4 Code 0x0000 Code 0x1000 Code 0x2000 Code 0x3000 Code 0x3FFF 0.8 3 0.6 DAC Output (V) 'VOUT (V) 0.4 0.2 0 -0.2 -0.4 Sourcing 5.5V Sourcing 2.7V Sinking 5.5V Sinking 2.7V -0.6 -0.8 5 10 15 20 Load Current (mA) 25 1 0 -1 -1 0 2 -2 -60 30 -40 D033 Figure 31. Headroom/Footroom vs Load Current -20 0 20 Load Current (mA) 40 60 D034 Figure 32. Source and Sink Capability with Gain = ½ 7 4 6 0x3FFF 0x3000 2 0x2000 1 0x1000 0x0000 0 0x3FFF 5 DAC Output (V) DAC Output (V) 3 0x3000 4 3 0x2000 2 0x1000 1 0x0000 0 -1 -1 -2 -60 -40 -20 0 20 Load Current (mA) 40 60 -2 -60 -40 D035 Figure 33. Source and Sink Capability with Gain = 1 40 60 D036 Figure 34. Source and Sink Capability with Gain = 2 Small Signal VOUT (3 LSB/div) Large Signal VOUT (2 V/div) CS (5 V/div) Small Signal VOUT (3 LSB/div) Large Signal VOUT (2 V/div) CS (5 V/div) Time (2 Psec/div) Time (2 Psec/div) D037 Gain = 1 D038 Gain = 1 Figure 35. Full-Scale Settling Time, Rising Edge 14 -20 0 20 Load Current (mA) Figure 36. Full-Scale Settling Time, Falling Edge Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. VOUT (2.5 mV/div) CS (5 V/div) VOUT (2.5mV/div) CS (5 V/div) Time (0.5 Ps/div) Time (0.5 Ps/div) D039 Gain = 1 D040 Gain = 1 Figure 37. Glitch Impulse, Falling Edge, 1 LSB Step Figure 38. Glitch Impulse, Rising Edge, 1 LSB Step VDD (1.5 V/div) VOUT (1 V/div) VDD (1.5 V/div) VOUT (10 mV/div) Time (600Ps/div) Time (600 Ps/div) D042 D041 Gain = 1 Gain = 1 Figure 39. Power-On, Reset to Zero Scale Figure 40. Power-On, Reset to Midscale VDD (1.5 V/div) VOUT (1 V/div) VIO (1.5 V/div) VOUT (1 V/div) Time (600Ps/div) Time (600Ps/div) D044 Gain = 1. DAC code at midscale D060 Gain = 1. DAC code at midscale Figure 41. VDD Power-Down Figure 42. VIO Power-Down Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 15 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Typical Characteristics (continued) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. SCLK (5 V/div) VOUT (1 mV/div) VOUT (200 PV/div) CS (5 V/div) Time (2 Psec/div) Time (5 Psec/div) D045 D046 Gain = 1. Measured DAC at midscale. All other DACs switch from code 32 to full scale Gain = 1. DAC code at midscale Figure 43. Channel to Channel Crosstalk Figure 44. Clock Feedthrough with SCLK = 1 MHz 0 300 Gain = 1 Gain = 2 -10 -20 250 -30 Noise (nV/—Hz) AC PSRR (dB) -40 -50 -60 -70 -80 200 150 100 -90 -100 50 -110 -120 1 10 100 1000 Frequency (Hz) 10000 0 10 2030 50 100 200 100000 D047 Gain = 1. VDD = 5 V + 200 mVPP (Sinusoid). DAC code at fullscale 100000 D048 VNOISE (2 PV/div) Figure 46. DAC Output Noise Density vs Frequency D049 Gain = 1. External Reference = 2.5 V. DAC code at midscale Figure 47. DAC Output Noise with External Reference 0.1 Hz to 10 Hz 16 10000 External Reference = 2.5 V. DAC code at midscale Figure 45. DAC Output AC PSRR vs Frequency VNOISE (2 PV/div) 5001000 Frequency (Hz) D050 Gain = 1. DAC code at midscale Figure 48. DAC Output Noise with Internal Reference 0.1 Hz to 10 Hz Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Typical Characteristics (continued) 2.505 2.505 2.5025 2.5025 Internal Reference (V) Internal Reference (V) At TA = 25°C, VDD = 5.5 V, Internal Reference = 2.5 V, Gain = 2, DAC outputs unloaded, unless otherwise noted. 2.5 2.4975 2.495 -40 -25 -10 5 20 35 50 65 Temperature (qC) 80 95 2.5 2.4975 2.495 2.7 110 125 3.1 3.5 3.9 4.3 VDD (V) D051 Figure 49. Internal Reference Voltage vs Temperature 4.7 5.1 5.5 D053 Figure 50. Internal Reference Voltage vs Supply Voltage 2.505 800 2.5025 600 Noise (nV/—Hz) Internal Reference (V) 700 2.5 2.4975 500 400 300 200 100 2.495 0 200 400 600 800 1000 Hours 1200 1400 0 10 2030 50 100 200 1600 D055 Figure 51. Internal Reference Voltage vs Time 5001000 Frequency (Hz) 10000 100000 D056 Figure 52. Internal Reference Noise Density vs Frequency 40 35 Number of Units VNOISE (2 PV/div) 30 25 20 15 10 5 0 0 1 2 3 Temperature Drift (ppm/qC) D057 4 5 D058 0.1 Hz to 10 Hz Figure 53. Internal Reference Noise Figure 54. Internal Reference Temperature Drift Histogram Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 17 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8 Detailed Description 8.1 Overview The DACx0504 is a pin-compatible family of low-power, four-channel, buffered voltage-output digital-to-analog converters (DACs) with 16- and 14-bit resolution. The DACx0504 includes a 2.5 V internal reference and userselectable gain configuration. providing full-scale output voltages of 1.25 V (gain = ½), 2.5 V (gain = 1), or 5 V (gain = 2). The device operates from a single 2.7 V to 5.5 V supply, is specified monotonic, and provides high linearity of ±1 LSB INL. Communication to the DACx0504 is performed through a 4-wire serial interface that supports stand-alone and daisy-chain operation. The optional frame-error checking provides added robustness to the DACx0504 serial interface. The DACx0504 incorporates a power-on-reset circuit and RSTSEL pin that powers up and maintains the DAC outputs at either zero scale or midscale until a valid code is written to the device. 8.2 Functional Block Diagram VIO VDD REFDIV REF GAIN Internal Reference DACx0504 ÷1 or ÷2 GAIN ×1 or ×2 SCLK DAC Buffer SDO/ALARM CS Interface Logic SDI LDAC DAC Register DAC OUT0 BUF Channel 0 Channel 1 OUT1 Channel 2 OUT2 Channel 3 OUT3 Power On Reset RSTSEL Power Down Logic Resistive Network GND Copyright © 2017, Texas Instruments Incorporated 18 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.3 Feature Description 8.3.1 Digital-to-Analog Converter (DAC) Each output channel in the DACx0504 consists of an R-2R ladder architecture followed by an output buffer amplifier. Figure 55 shows a block diagram of the DAC architecture. REF 2.5-V Reference REF Divider (÷1 or ÷2) Serial Interface DAC Data Register READ DIV GAIN WRITE DAC Buffer Register DAC Active Register R-2R Gain (×1 or ×2) VOUT DAC Output (asynchronous mode) LDAC Trigger (synchronous mode) GND Copyright © 2017, Texas Instruments Incorporated Figure 55. DACx0504 DAC Block Diagram 8.3.1.1 DAC Transfer Function The input data are written to the individual DAC data registers in straight binary format. After a power-on or a reset event, all DAC registers are set to either zero code or midscale code, as determined by the RSTSEL pin. The DAC transfer function is given by Equation 1. CODE VREF VOUT u u GAIN DIV 2n where • • • • • CODE = decimal equivalent of the binary code that is loaded to the DAC register. CODE ranges from 0 to 2n – 1. VREF = DAC reference voltage. Either VREFOUT from the internal 2.5 V reference or VREFIN if using an external one. n = resolution in bits. Either 14 (DAC70504) or 16 (DAC80504) DIV = 1 or 2 as set by the REFDIV pin after a reset event or by the REF-DIV bit in the GAIN register. GAIN = 1 or 2 as set by the GAIN pin after a reset event or by the BUFF-GAIN bit for that DAC channel in the GAIN register. (1) Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 19 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com Feature Description (continued) 8.3.1.2 Output Amplifiers The DACx0504 output buffer amplifier is capable of generating rail-to-rail voltages on its output, giving a maximum output range of 0 V to VDD. Each buffer amplifier is capable of driving a load of 2 kΩ in parallel with 10 nF to GND. The full-scale output voltage for each channel is determined by the reference voltage (VREF), the reference divider setting (DIV), and the output buffer gain for that channel (GAIN), as shown in Table 1. After a power-up or reset event the DIV and GAIN settings are set by the REFDIV and GAIN pins, respectively. During normal operation the DIV and GAIN settings can be reconfigured through the REF-DIV and BUFF-GAIN bit (see Equation 1). The GAIN setting for each output channel can be individually configured thus enabling independent output voltage ranges for each DAC output. Table 1. DAC Output Range Configuration DIV SETTING GAIN SETTING ÷2 ×1 0 V to ½ × VREF DAC OUTPUT RANGE ÷1 ×1 Not recommended ÷2 ×2 0 V to VREF ÷1 ×2 0 V to 2 × VREF 8.3.1.3 DAC Register Structure Data written to the DAC data registers is initially stored in the DAC buffer registers. Transfer of data from the DAC buffer registers to the active DAC registers can be configured to happen immediately (asynchronous mode) or initiated by an LDAC trigger (synchronous mode). Once the DAC active registers are updated, the DAC outputs change to their new values. When the host reads from a DAC Data register, the value held in the DAC buffer register is returned (not the value held in the DAC active register). 8.3.1.3.1 DAC Register Synchronous and Asynchronous Updates The update mode for each DAC channel is determined by the status of its corresponding SYNC-EN bit. In asynchronous mode, a write to the DAC data register results in an immediate update of the DAC active register and DAC output on CS rising edge. In synchronous mode, writing to the DAC data register does not automatically update the DAC output. Instead the update occurs only after an LDAC trigger event. An LDAC trigger is generated either through the LDAC bit in the TRIGGER register or by the LDAC pin. The synchronous update mode enables simultaneous update of multiple DAC outputs. In both update modes a minimum wait time of 1 µs is required between DAC output updates. 8.3.1.3.2 Broadcast DAC Register The DAC broadcast register enables a simultaneous update of multiple DAC outputs with the same value with a single register write. Each DAC channel can be configured to update or remain unaffected by a broadcast command by setting the corresponding DAC-BRDCAST-EN bit in the SYNC register. A register write to the BRDCAST-DATA register forces those DAC channels that have been configured for broadcast operation to update their outputs. The DAC ouputs update to the broadcast value on CS rising edge independently of their synchronous mode configuration. 20 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.3.2 Internal Reference The DACx0504 includes a 2.5 V precision bandgap reference enabled by default. Operation from an external reference is supported by disabling the internal reference in the CONFIG register. The internal reference is externally available at the REF pin. A minimum 150 nF capacitor is recommended between the reference output and GND for noise filtering. 8.3.2.1 Reference Divider The reference voltage to the device, either from the internal reference or an external one can be divided by a factor of two by tying the REFDIV pin high at power-up or by setting the REF-DIV bit in the GAIN register to 1 during normal operation. The reference voltage divider provides additional flexibility in setting the full-scale output voltage for each DAC output and must be configured to make certain that there is sufficient headroom from VDD to the DAC operating reference voltage (VREF/DIV). See the Recommended Operating Conditions table for more information. Improper configuration of the reference divider issues a reference alarm condition. In this case, the reference buffer is shut down, and all the DAC outputs go to 0 V. The DAC data registers are unaffected by the alarm condition thus enabling the DAC output to return to normal operation once the reference divider is configured correctly. The reference alarm status can be read from the REF-ALM bit in the STATUS register. Additionally by setting ALM-EN = 1 and ALM-SEL = 1 in the CONFIG register, the SDO/ALARM pin is configured as a reference alarm pin. 8.3.2.2 Solder Heat Reflow A known behavior of IC reference voltage circuits is the shift induced by the soldering process. Figure 56 shows the effect of solder heat reflow for the DACx0504 internal reference. 70% Precentage of Units 60% Presolder Heat Reflow Postsolder Heat Reflow 50% 40% 30% 20% 10% 0 2.4975 2.4980 2.4985 2.4990 2.4995 2.5000 2.5005 2.5010 VREFOUT (V) D059 Figure 56. Solder Heat Reflow Reference Voltage Shift Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 21 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8.3.3 Device Reset Options 8.3.3.1 Power-on-Reset (POR) The DACx0504 includes a power-on reset function that controls the output voltage at power up. After the VDD and VIO supplies have been established a POR event is issued. The POR causes all registers to initialize to their default values and communication with the device is valid only after a 250 µs power-on-reset delay. The default value for all DACs is either zero-code or midscale-code as determined by the RSTSEL pin. Each DAC channel remains at the power-up voltage until a valid command is written to it. The POR circuit requires specific supply levels to discharge the internal capacitors and to reset the device on power up, as indicated in Figure 57 and Figure 58. In order to initiate a POR event, VDD or VIO must be below their corresponding low thresholds for at least 100 µs. If VDD and VIO remain above their specified high threshold a POR event will not occur. When the supplies drop below their high threshold but remain over the lower one (shown as the undefined region), the device may or may not reset under all specified temperature and powersupply conditions. VDD (V) VIO (V) 5.50 5.50 No Power-On Reset Specified Supply Voltage Range No Power-On Reset Specified Supply Voltage Range 2.70 2.20 Undefined 1.70 1.50 1.20 Undefined 0.70 Power-On Reset Power-On Reset 0.00 0.00 Figure 57. Threshold Levels for VDD POR Circuit Figure 58. Threshold Levels for VIO POR Circuit 8.3.3.2 Software Reset A device software reset event is initiated by writing the reserved code 0x1010 to SOFT-RESET in the TRIGGER register. The software reset command is triggered on the CS rising edge of the instruction. A software reset initiates a POR event. 22 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.4 Device Functional Modes 8.4.1 Stand-Alone Operation A serial interface access cycle is initiated by asserting the CS pin low. The serial clock SCLK can be a continuous or gated clock. SDI data are clocked on SCLK falling edges. A regular serial interface access cycle is 24 bits long with error checking disabled and 32 bits long with error checking enabled, thus the CS pin must stay low for at least 24 or 32 SCLK falling edges. The access cycle ends when the CS pin is de-asserted high. If the access cycle contains less than the minimum clock edges, the communication is ignored. If the access cycle contains more than the minimum clock edges are present, only the last 24 or 32 bits are used by the device. When CS is high, the SCLK and SDI signals are blocked and the SDO pin is in a Hi-Z state. In an error checking disabled access cycle (24-bits long) the first byte input to SDI is the instruction cycle which identifies the request as a read or write command and the 4-bit address to be accessed. The following bits in the cycle form the data cycle, as shown in Table 2. Table 2. Serial Interface Access Cycle BIT FIELD 23 RW 22:20 Reserved 19:16 A[3:0] 15:0 DI[15:0] DESCRIPTION Identifies the communication as a read or write command to the addressed register. R/W = 0 sets a write operation. R/W = 1 sets a read operation. Reserved bits. Must be filled with zeros. Register address. Specifies the register to be accessed during the read or write operation. Data cycle bits. If a write command, the data cycle bits are the values to be written to the register with address A[3:0]. If a read command, the data cycle bits are don’t care values. A read operation is initiated by issuing a read command access cycle. After the read command, a second access cycle must be issued to get the requested data, as shown in Table 3. Data are clocked out on SDO pin either on the falling edge or rising edge of SCLK according to the FSDO bit in the CONFIG register. Table 3. SDO Output Access Cycle BIT FIELD 23 RW 22:20 Reserved 19:16 A[3:0] 15:0 DO[15:0] DESCRIPTION Echo RW from previous access cycle. Echo bits 22:20 from previous access cycle (all zeros). Echo address from previous access cycle. Readback data requested on previous access cycle. 8.4.2 Daisy-Chain Operation For systems that contain more than one DACx0504 devices, the SDO pin can be used to daisy-chain them together. Daisy-chain operation is useful in reducing the number of serial interface lines. The first falling edge on the CS pin starts the operation cycle. If more than 24 SCLK pulses are applied while the CS pin is kept low, the data ripples out of the shift register and is clocked out on the SDO pin either on the falling edge or rising edge of SCLK according to the FSDO bit. By connecting the SDO output of the first device to the SDI input of the next device in the chain, a multiple-device interface is constructed. Each device in the system requires 24 clock pulses. As a result the total number of clock cycles must be equal to 24 × N, where N is the total number of DACx0504 devices in the daisy chain. When the serial transfer to all devices is complete the CS signal is taken high. This action transfers the data from the serial peripheral interface (SPI) shift registers to the internal registers of each device in the daisy chain and prevents any further data from being clocked into the input shift register. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 23 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com C B DACx0504 DACx0504 DACx0504 SDO SDI A SDI SDO SDI SCLK SCLK SCLK CS CS CS SDO Copyright © 2017, Texas Instruments Incorporated Figure 59. Daisy-Chain Layout 8.4.3 Frame Error Checking If the DACx0504 is used in a noisy environment, error checking can be used to check the integrity of SPI data communication between the device and the host processor. This feature can be enabled by setting the CRC-EN bit in the CONFIG register. The error checking scheme is based on the CRC-8-ATM (HEC) polynomial x8 + x2 + x + 1 (that is, 100000111). When error checking is enabled, the serial interface access cycle width is 32 bits. The normal 24-bit SPI data are appended with an 8-bit CRC polynomial by the host processor before feeding it to the device, as shown in Table 4. In all serial interface readback operations the CRC polynomial is output on the SDO pin as part of the 32-bit cycle. Table 4. Error Checking Serial Interface Access Cycle BIT FIELD 31 RW 30 CRC-ERROR 29:28 Reserved 27:24 A[3:0] 23:8 DI[15:0] 7:0 CRC DESCRIPTION Identifies the communication as a read or write command to the addressed register. R/W = 0 sets a write operation. R/W = 1 sets a read operation. Reserved bit. Set to zero. Reserved bits. Must be filled with zeros. Register address. Specifies the register to be accessed during the read or write operation. Data cycle bits. If a write command, the data cycle bits are the values to be written to the register with address A[3:0]. If a read command, the data cycle bits are don’t care values. 8-bit CRC polynomial. The DACx0504 decodes the 32-bit access cycle to compute the CRC remainder on CS rising edges. If no error exists, the CRC remainder is zero and data are accepted by the device. A write operation failing the CRC check causes the data to be ignored by the device. After the write command, a second access cycle can be issued to determine the error checking result (CRC-ERROR bit) on the SDO pin, as shown in Table 5. Additionally, by setting ALM-EN = 1 and ALM-SEL = 0 in the CONFIG register, the SDO/ALARM pin is configured as a CRC alarm pin. Table 5. Write Operation Error Checking Cycle BIT 24 FIELD DESCRIPTION 31 RW 30 CRC-ERROR Echo RW from previous access cycle (RW = 0). Returns a 1 when a CRC error is detected, 0 otherwise. 29:28 Reserved Echo bits 29:28 from previous access cycle (all zeros). 27:24 A[3:0] 23:8 DO[15:0] 7:0 CRC Echo address from previous access cycle. Echo data from previous access cycle. Calculated CRC value of bits 31:8. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 A read operation must be followed by a second access cycle to get the requested data on the SDO pin. The error check result (CRC-ERROR bit) from the read command is output on the SDO pin, as shown in Table 6. As in the case of a write operation failing the CRC check, the SDO/ALARM pin if configured as a CRC alarm pin can be used to indicate a read command CRC failure. Table 6. Read Operation Error Checking Cycle BIT FIELD 31 RW DESCRIPTION 30 CRC-ERROR Returns a 1 when a CRC error is detected, 0 otherwise. 29:28 Reserved Echo bits 29:28 from previous access cycle (all zeros). 27:24 A[3:0] 23:8 DO[15:0] 7:0 CRC Echo RW from previous access cycle (RW = 1). Echo address from previous access cycle. Readback data requested on previous access cycle. Calculated CRC value of bits 31:8. 8.4.4 Power-Down Mode The DACx0504 DAC output amplifiers and internal reference can be independently powered down through the CONFIG register. At power-up all output channels and the device internal referece are active by defaul. A DAC output channel in power-down mode is connected internally to GND through a 1-kΩ resistor. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 25 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8.5 Programming The DACx0504 is controlled through a flexible four-wire serial interface that is compatible with SPI type interfaces used on many microcontrollers and DSP controllers. The interface provides read and write access to all DACx0504 registers and can also be configured to daisy-chain multiple devices for write operations. The DACx0504 incorporates an optional error checking mode to validate SPI data communication integrity in noisy environments. Table 7 shows the SPI timing requirements. Figure 60 and Figure 61 show the SPI write and read timing diagrams, respectively. Figure 62 shows the digital logic timing diagram. Table 7. Programming Timing Requirements (1) VIO = 1.7 V to 2.7 V MIN NOM VIO = 2.7 V to 5.5 V MAX MIN NOM MAX UNIT SERIAL INTERFACE – WRITE OPERATION fSCLK SCLK frequency tSCLKHIGH SCLK high time 9 50 9 50 MHz ns tSCLKLOW SCLK low time 9 9 ns tSDIS SDI setup 5 5 ns tSDIH SDI hold 10 10 ns tCSS CS to SCLK falling edge setup 13 13 ns tCSH SCLK falling edge to CS rising edge 10 10 ns tCSHIGH CS high time 15 15 ns tCSIGNORE SCLK falling edge to CS ignore 7 7 ns SERIAL INTERFACE – READ AND DAISY CHAIN OPERATION, FSDO = 0 fSCLK SCLK frequency tSCLKHIGH SCLK high time 35 12 25 18 ns tSCLKLOW SCLK low time 35 25 ns tSDIS SDI setup 5 5 ns tSDIH SDI hold 10 10 ns tCSS CS to SCLK falling edge setup 32 20 ns tCSH SCLK falling edge to CS rising edge 10 10 ns tCSHIGH CS high time 15 tSDODLY SDO output delay from SCLK rising edge 3.5 33.5 3.5 23 ns tSDODZ SDO driven to tri-state 0 30 0 25 ns tCSIGNORE SCLK falling edge to CS ignore 7 15 MHz ns 7 ns SERIAL INTERFACE – READ AND DAISY CHAIN OPERATION, FSDO = 1 fSCLK SCLK frequency tSCLKHIGH SCLK high time 22 20 18 25 ns tSCLKLOW SCLK low time 22 18 ns tSDIS SDI setup 5 5 ns tSDIH SDI hold 10 10 ns tCSS CS to SCLK falling edge setup 32 20 ns tCSH SCLK falling edge to CS rising edge 10 10 ns tCSHIGH CS high time 15 15 ns tSDODLY SDO output delay from SCLK falling edge 3.5 45 3.5 32 ns tSDODZ SDO driven to tri-state 0 30 0 25 ns tCSIGNORE SCLK falling edge to CS ignore 7 7 MHz ns DIGITAL LOGIC tRSTDLYPOR POR reset delay tDACWAIT Sequential DAC output updates (1) 26 170 1 250 170 1 250 µs µs All input signals are specified at tR = tF = 1 ns/V (10% to 90% of VIO), timed from a voltage level of (VIL + VIH) / 2, VDD = 2.7 V to 5.5 V, VIO = 1.7 V to 5.5 V, VREFIN = 1.25 V to 5.5 V, SDO loaded with 20 pF, and TA = –40°C to +125°C (unless otherwise noted) Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 tCSHIGH tCSS tCSH CS tCSIGNORE tSCLKLOW SCLK tSCLKHIGH SDI Bit 23 Bit 1 Bit 0 tSDIH tSDIS Figure 60. Serial Interface Write Timing Diagram tCSHIGH tCSS tCSH CS tCSIGNORE tSCLKLOW SCLK tSCLKHIGH FIRST READ COMMAND SDI Bit 23 tSDIS Bit 22 ANY COMMAND Bit 0 Bit 23 Bit 1 Bit 0 Bit 23 Bit 1 Bit 0 tSDIH SDO FSDO = 0 tSDODZ tSDODLY DATA FROM FIRST READ COMMAND SDO FSDO = 1 Bit 23 Bit 1 Bit 0 X tSDODZ tSDODLY DATA FROM FIRST READ COMMAND Figure 61. Serial Interface Read Timing Diagram tLDACS tLDACH CS LDAC Figure 62. Digital Logic Timing Diagram Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 27 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8.6 Register Map Table 8. Register Map ADDRESS BITS REGISTER NOP 28 TYPE W DATA BITS RESET A3 A2 A1 A0 0000 0 0 0 0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 NOP DEVICE ID R — 0 0 0 1 SYNC R/W FF00 0 0 1 0 DEVICEID CONFIG R/W 0000 0 0 1 1 GAIN R/W 0000 0 1 0 0 TRIGGER W 0000 0 1 0 1 BRDCAST R/W 0000 0 1 1 0 STATUS R/W 0000 0 1 1 1 DAC0 R/W 0000 1 0 0 0 DAC0-DATA[15:0] DAC1 R/W 0000 1 0 0 1 DAC1-DATA[15:0] DAC2 R/W 0000 1 0 1 0 DAC2-DATA[15:0] DAC3 R/W 0000 1 0 1 1 DAC3-DATA[15:0] All Others — — — — — — RESERVED RESERVED RESERVED ALM SEL VERSIONID DACx-BRDCAST-EN ALM EN CRC EN F SDO D SDO RESERVED RESERVED DACx-SYNC-EN REF PWD WN RESERVED DACx-PWDWN REF DIVEN RESERVED BUFFx-GAIN L DAC RESERVED SOFT-RESET[3:0] BRDCAST-DATA[15:0] REF ALM RESERVED Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.6.1 NOP Register (address = 0x00) [reset = 0x0000] Figure 63. NOP Register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NOP W LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 9. NOP Register Field Descriptions Bit Field Type Reset Description 15:0 NOP W 0x0000 No operation. Write 0000h for proper no-operation command 8.6.2 DEVICE ID Register (address = 0x01) [reset = 0x---] Figure 64. DEVICE ID Register 15 14 13 12 11 10 9 8 DEVICEID R 7 6 5 4 3 2 1 0 VERSIONID R LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 10. DEVICE ID Field Descriptions Bit Field Type Reset Description 15:2 DEVICEID R ---- Device ID: D15 Reserved - 0 D14:12 Resolution - 000 (16-bit); 001 (14-bit) D11:4 Channels - 0100 (4 channels) D7 Reset - Determined by RSTSEL pin. 0 (reset to zero); 1 (reset to midscale) D6:2 Reserved - 00101 1:0 VERSIONID R 10 Version ID. Subject to change Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 29 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8.6.3 SYNC Register (address = 0x2) [reset = 0xFF00] Figure 65. SYNC Register 15 14 13 12 11 DAC3BRDCAST-EN R/W 10 DAC2BRDCAST-EN R/W 9 DAC1BRDCAST-EN R/W 8 DAC0BRDCAST-EN R/W 5 4 3 DAC3-SYNCEN R/W 2 DAC2-SYNCEN R/W 1 DAC1-SYNCEN R/W 0 DAC0-SYNCEN R/W Reserved — 7 6 Reserved — LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 11. SYNC Register Field Descriptions Bit Field Type Reset Description Reserved — 1111 Reserved for factory use 11 DAC3-BRDCAST-EN R/W 1 10 DAC2-BRDCAST-EN R/W 1 9 DAC1-BRDCAST-EN R/W 1 8 DAC0-BRDCAST-EN R/W 1 When set to 1 the corresponding DAC is set to update its output after a serial interface write to the BRDCAST register. When cleared to 0 the corresponding DAC output remains unaffected after a serial interface write to the BRDCAST register. 15:12 7:4 30 Reserved — 0000 Reserved for factory use 3 DAC3-SYNC-EN R/W 0 2 DAC2-SYNC-EN R/W 0 1 DAC1-SYNC-EN R/W 0 When set to 1 the corresponding DAC output is set to update in response to an LDAC trigger (synchronous mode). When cleared to 0 the corresponding DAC output is set to update immediately on a CS rising edge (asynchronous mode). 0 DAC0-SYNC-EN R/W 0 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.6.4 CONFIG Register (address = 0x3) [reset = 0x0000] Figure 66. CONFIG Register 15 14 Reserved — 7 13 ALM-SEL R/W 12 ALM-EN R/W 5 4 6 11 CRC-EN R/W 10 FSDO R/W 9 DSDO R/W 8 REF-PWDWN R/W 3 2 1 0 DAC3-PWDWN DAC2-PWDWN DAC1-PWDWN DAC0-PWDWN R/W R/W R/W R/W Reserved — LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 12. CONFIG Register Field Descriptions Bit Field Type Reset Description 15:14 Reserved — 00 Reserved for factory use 13 ALM-SEL R/W 0 ALARM select. 0: ALARM pin is CRC-ERROR 1: ALARM pin is REF-ALARM 12 ALM-EN R/W 0 Configure SDO/ALARM pin. When 1: SDO/ALARM pin is an active-low, open-drain, alarm pin. An external 10 kΩ pullup resistor to VIO is required. FSDO and DSDO bits are ignored. When 0: SDO/ALARM pin is a serial interface, push-pull, SDO pin 11 CRC-EN R/W 0 CRC enable bit. Set to 1 to enable CRC. Set to 0 to disable 10 FSDO R/W 0 Fast SDO bit (half-cycle speedup). When 0, SDO updates on an SCLK rising edge. When 1, SDO updates a half-cycle earlier, during an SCLK falling edge. 9 DSDO R/W 0 Disable SDO bit. When 1, SDO is always tri-stated. When 0, SDO is driven while CS is low, and tri-stated while CS is high 8 REF-PWDWN R/W 0 When set to 1 disables the device internal reference Reserved — 0000 Reserved for factory use 3 DAC3-PWDWN R/W 0 2 DAC2-PWDWN R/W 0 When set to 1 the corresponding DAC is set in power-down mode and its output is connected to GND through a 1 kΩ internal resistor. 1 DAC1-PWDWN R/W 0 0 DAC0-PWDWN R/W 0 7:4 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 31 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 8.6.5 GAIN Register (address = 0x04) [reset = 0x---] Figure 67. GAIN Register 15 14 7 6 13 12 Reserved — 11 10 9 8 REFDIV-EN R/W 5 4 3 BUFF3-GAIN R/W 2 BUFF2-GAIN R/W 1 BUFF1-GAIN R/W 0 BUFF0-GAIN R/W Reserved — LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 13. GAIN Register Field Descriptions Bit 15:9 8 7:4 Field Type Reset Description Reserved — 0 Reserved for factory use. REFDIV-EN R/W 0/1 When set to 1 the reference voltage is internally divided by a factor of 2. When cleared to 0 the reference voltage is unaffected. Default value is determined by the REFDIV pin. Reserved — 0000 Reserved for factory use 3 BUFF3-GAIN R/W 0/1 2 BUFF2-GAIN R/W 0/1 1 BUFF1-GAIN R/W 0/1 0 BUFF0-GAIN R/W 0/1 When set to 1 the buffer amplifier for corresponding DAC has a gain of 2. When cleared to 0 the buffer amplifier for corresponding DAC has a gain of 1. Default value is determined by the GAIN pin. 8.6.6 TRIGGER Register (address = 0x05) [reset = 0x0000] Figure 68. TRIGGER Register 15 14 13 12 11 10 Reserved — 9 8 7 6 5 4 LDAC W 3 2 1 SOFT-RESET[3:0] W 0 LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 14. TRIGGER Register Field Descriptions Bit 15:5 4 3:0 32 Field Type Reset Description Reserved — 0 Reserved for factory use. LDAC W 0 Set this bit to 1 to synchronously load those DACs that have been set in synchronous mode in the SYNC register. SOFT-RESET[3:0] W 0x0 When set to the reserved code 1010 resets the device to its default state. Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 8.6.7 BRDCAST Register (address = 0x6) [reset = 0x0000] Figure 69. BRDCAST Register 15 14 13 12 11 10 9 8 7 6 BRDCAST-DATA[15:0] R/W 5 4 3 2 1 0 LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 15. BRDCAST Register Field Descriptions Bit 15:0 Field Type Reset Description BRDCAST-DATA[15:0] R/W 0x0000 Writing to the BRDCAST register forces those DAC channels that have been set to broadcast in the SYNC register to update their active data register with the BRDCAST-DATA value. Data are MSB aligned in straight binary format and follows the format below: DAC80504: { DATA[15:0] } DAC70504: { DATA[13:0], x, x } x – Don’t care bits 8.6.8 STATUS Register (address = 0x7) [reset = 0x0000] Figure 70. STATUS Register 15 14 13 12 11 10 9 8 Reserved 7 6 5 4 3 2 1 — 0 REFALM R/W LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 16. STATUS Register Field Descriptions Field Type Reset Description 15:1 Bit Reserved — 0 Reserved for factory use. 0 REF-ALM R 0 Reference alarm bit. Reads 1 when the difference between VREF/DIV and VDD is below the required minimum analog threshold. Reads 0 otherwise. 8.6.9 DACx Register (address = 0x8 to 0xF) [reset = 0x0000 or 0x8000] Figure 71. DACx Register 15 14 13 12 11 10 9 8 7 DACx-DATA[15:0] R/W 6 5 4 3 2 1 0 LEGEND: R/W = Read/Write; R = Read only; -n = value after reset Table 17. DACx Register Field Descriptions Bit 15:0 Field Type Reset Description DACx-DATA[15:0] R/W 0x0000 or 0x8000 Stores the 16- or 14-bit data to be loaded to DACx in MSB aligned straight binary format. The default value is determined by the RSTSEL pin. Data follows the format below: DAC80504: { DATA[15:0] } DAC70504: { DATA[13:0], x, x } x – Don’t care bits Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 33 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 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 The high linearity, small package size and wide temperature range make the DACx0504 suitable in applications such as optical networking, wireless infrastructure, industrial automation and data acquisition systems. The device incorporates a 2.5 V internal reference with an internal reference divider circuit that enables full-scale DAC output voltages of 1.25 V, 2.5 V, or 5 V. 9.1.1 Interfacing to a Microcontroller Figure 72 displays a typical serial interface that may be observed when connecting the DACx0504 SPI serial interface to a (master) microcontroller type platform. The setup for the interface is as follows: the microcontroller output SPI CLK drives the SCLK pin of the DACx0504, while the DACx0504 SDI pin is driven by the MOSI pin of the microcontroller. The CS pin of the DACx0504 can be asserted from a general program input/output pin of the microcontroller. When data are to be transmitted to the DACx0504, the CS pin is taken low. The data from the microcontroller is then transmitted to the DACx0504, totaling 24 bits latched into the DACx0504 device through the falling edge of SCLK. CS is then brought high after the completed write. The DACx0504 requires data with the MSB as the first bit received. Microcontroller CS DACx0504 CS SCLK SCLK MOSI SDI MISO SDO Copyright © 2017, Texas Instruments Incorporated Figure 72. Typical Serial Interface 34 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 Application Information (continued) 9.1.2 Programmable Current Source Circuit The DACx0504 can be integrated into the circuit in Figure 73 to implement an improved Howland current pump for precise voltage to current conversions. Bidirectional current flow and high voltage compliance are two features of the circuit. With a matched resistor network, the load current of the circuit is shown by Equation 2. R2 R3 / R1 CODE u VREF u IL R3 (2) 2n The value of R3 in Equation 2 can be reduced to increase the output current drive of U3. U3 can drive ±20 mV in both directions with voltage compliance limited up to 15 V by the U3 voltage supply. Elimination of the circuit compensation capacitor C1 in the circuit is not suggested as a result of the change in the output impedance ZO, according to Equation 3. R1' R3 R1 R2 ZO R1 R2' R3' R1' R2 R3 (3) As shown in Equation 3, with matched resistors, ZO is infinite and the circuit is optimum for use as a current source. However, if unmatched resistors are used, ZO is positive or negative with negative output impedance being a potential cause of oscillation. Therefore, by incorporating C1 into the circuit, possible oscillation problems are eliminated. The value of C1 can be determined for critical applications; for most applications, however, a value of several pF is suggested. R2' 15 k VDD REF VDD VREF C1 10 pF VDAC R1' 150 k DACx0504 R3' 50 U3 OPA277 GND VOUT R3 50 GND R1 150 k R2 15 k IL LOAD Copyright © 2017, Texas Instruments Incorporated Figure 73. Programmable Bidirectional Current Source Circuit Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 35 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 9.2 Typical Application The DACx0504 is designed for single-supply operation; however, a bipolar output is also possible using the circuit shown in Figure 74. GND 15 V DACx0504 VDAC R2 REF OPA192 VOUT VREF ±15 V R1 R3 VREF Copyright © 2017, Texas Instruments Incorporated Figure 74. Bipolar Operation Using the DACx0504 9.2.1 Design Requirements The circuit shown in Figure 74 gives a bipolar output voltage at VOUT. When GAIN = 1, VOUT can be calculated using Equation 4: ª§ R3 · º CODE · § R3 R3 · § u VOUT CODE «¨ VREF u 1 V ¨ ¸ ¨ ¸» REF ¸ R1 ¹ »¼ 2n ¹ © R2 R1 ¹ © «¬© where • • • • VOUT(CODE) = output voltage versus code CODE = 0 to 2n – 1. This is the digital code loaded to the DAC VREF = reference voltage applied to the DACx0504 n = resolution in bits (4) Table 18. Design Parameters PARAMETER VALUE VOUT ±10 V VREF 2.5 V n 12 9.2.2 Detailed Design Procedure The bipolar output span can be calculated through Equation 4 by defining a few parameters, the first being the value for the reference voltage. Once a reference voltage is chosen, the gain resistors can be set accordingly by determining the desired VOUT at code 0 and code 2n. For a VREF of 2.5 V and a desired output voltage range of ±10 V the calculation is as follows. CODE = 0: VOUT 0 § R3 · ¨ VREF u ¸ R1 ¹ © § R3 · ¨ 2.5V u ¸ R1 ¹ © (5) Setting the equation to minimum output span, VOUT(0) = –10 V, will reduce the equation to: R3/R1 = 4: CODE = 4096: Setting the equation to maximum output scan, VOUT(4096) = 10 V, and R3/R1 = 4 will reduce the equation to: R3/R2 = 3 It is important to note that the maximum code of a 12-bit DAC is 4095; code 4096 was used to simplify the equation above. For practical use, the true output span will encompass a range of –10 V to (10 V – 1 LSB), which in this case is –10 V to 9.995 V. 36 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 9.2.3 Application Curve The ±10 V output span with a reference voltage of 2.5 V can be achieved by using values of 30 kΩ, 10 kΩ, and 7.5 kΩ for R3, R2, and R1, respectively. A curve to illustrate this output span is shown in Figure 75. For this example, 1% tolerance resistors were used in evaluating bipolar operation. 10 Output Voltage (V) 5 0 -5 -10 0 512 1024 1536 2048 2560 DAC Code 3072 3584 4096 D001 Figure 75. Bipolar Operation Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 37 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 10 Power Supply Recommendations The DACx0504 operates within the specified VDD supply range of 2.7 V to 5.5 V, and VIO supply range of 1.7 V to 5.5 V. The DACx0504 does not require specific supply sequencing. The VDD supply must be well-regulated and low-noise. Switching power supplies and dc-dc converters often have high-frequency glitches or spikes riding on the output voltage. In addition, digital components can create similar high-frequency spikes. This noise can easily couple into the DAC output voltage through various paths between the power connections and analog output. In order to further minimize noise from the power supply, include a 1μF to 10-μF capacitor and 0.1-μF bypass capacitor. The current consumption on the VDD pin, the short-circuit current limit, and the load current for the device is listed in the Electrical Characteristics. The power supply must meet the aforementioned current requirements. 38 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 DAC80504, DAC70504 www.ti.com SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 11 Layout 11.1 Layout Guidelines A precision analog component requires careful layout, the list below provides some insight into good layout practices. • Bypass all power supply pins to ground with a low-ESR ceramic bypass capacitor. The typical recommended bypass capacitance is 0.1-µF to 0.22-µF ceramic with a X7R or NP0 dielectric. • Place power supplies and REF bypass capacitors close to the pins to minimize inductance and optimize performance. • Use a high-quality ceramic type NP0 or X7R for its optimal performance across temperature, and very low dissipation factor. • The digital and analog sections must have proper placement with respect to the digital pins and analog pins of the DACx0504 device. The separation of analog and digital blocks minimizes coupling into neighboring blocks, as well as interaction between analog and digital return currents. 11.2 Layout Example ANALOG SIDE GND POUR BYPASS CAPACITOR 4 BYPASS CAPACITORS 3 2 1 16 5 6 15 7 14 8 13 9 10 11 12 GND POUR DIGITAL SIDE Figure 76. DACx0504 Layout Example Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 39 DAC80504, DAC70504 SBAS871A – AUGUST 2017 – REVISED DECEMBER 2017 www.ti.com 12 Device and Documentation Support 12.1 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 19. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY DAC80504 Click here Click here Click here Click here Click here DAC70504 Click here Click here Click here Click here Click here 12.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 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. 40 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Product Folder Links: DAC80504 DAC70504 PACKAGE OPTION ADDENDUM www.ti.com 23-Dec-2017 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) DAC70504RTER ACTIVE WQFN RTE 16 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 70504 DAC70504RTET ACTIVE WQFN RTE 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 125 70504 XDAC80504RTET ACTIVE WQFN RTE 16 250 TBD Call TI Call TI -40 to 125 (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (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. (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. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 24-Dec-2017 TAPE AND REEL INFORMATION *All dimensions are nominal Device 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 DAC70504RTER WQFN RTE 16 3000 180.0 12.4 3.3 3.3 1.0 8.0 12.0 Q2 DAC70504RTET WQFN RTE 16 250 180.0 12.4 3.3 3.3 1.0 8.0 12.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 24-Dec-2017 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DAC70504RTER WQFN RTE 16 3000 195.0 200.0 45.0 DAC70504RTET WQFN RTE 16 250 195.0 200.0 45.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated (TI) reserves 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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