DAC 8534 ® DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 QUAD, 16-BIT, LOW-POWER, VOLTAGE OUTPUT, I C INTERFACE DIGITAL-TO-ANALOG CONVERTER 2 FEATURES • • • • • • • • • • • • • DESCRIPTION Micropower Operation: 950 µA at 5 V VDD Power-On Reset to Zero +2.7-V to +5.5-V Analog Power Supply 16-Bit Monotonic Settling Time: 10µs to ±0.003% FSR I2C™ Interface Up to 3.4 Mbps Data Transmit Capability On-Chip Output Buffer Amplifier, Rail-to-Rail Operation Double-Buffered Input Register Address Support for up to Sixteen DAC8574s Synchronous Update Support for up to 64 Channels Operation From –40°C to 105°C Small 16-Lead TSSOP Package APPLICATIONS • • • • • Process Control Data Acquisition Systems Closed-Loop Servo Control PC Peripherals Portable Instrumentation VDD The DAC8574 is a low-power, quad channel, 16-bit buffered voltage output DAC. Its on-chip precision output amplifier allows rail-to-rail output swing to be achieved. The DAC8574 utilizes an I2C compatible two wire serial interface supporting high-speed interface mode with address support of up to sixteen DAC8574s for a total of 64 channels on the bus. The DAC8574 requires an external reference voltage to set the output range of the DAC. The DAC8574 incorporates a power-on-reset circuit that ensures that the DAC output powers up at zero volts and remains there until a valid write takes place to the device. The DAC8574 contains a power-down feature, accessed via the internal control register, that reduces the current consumption of the device to 200 nA at 5 V. The low power consumption of this part in normal operation makes it ideally suited to portable battery operated equipment. The power consumption is less than 5 mW at VDD = 5 V reducing to 1 µW in power-down mode. The DAC8574 is available in a 16-lead TSSOP package. IOVDD VREFH Data Buffer A DAC Register A DAC A VOUTA VOUTB 18 Data Buffer D DAC Register D Buffer Control Register Control VOUTC DAC D VOUTD SCL I2C Block SDA Power-Down Control Logic Resistor Network 8 A0 A1 GND A2 A3 LDAC VREFL Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. I2C is a trademark of Philips Corporation. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2003–2004, Texas Instruments Incorporated DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER SPECIFICATION TEMPERATURE RANGE PACKAGE MARKING DAC8574 16-TSSOP PW –40°C TO +105°C D8574I ORDERING NUMBER TRANSPORT MEDIA DAC8574IPW 90 Piece Tube DAC8574IPWR 2000 Piece Tape and Reel PW PACKAGE (TOPVIEW) PIN DESCRIPTIONS PIN NAME VOUTA 1 16 A3 1 VOUTA Analog output voltage from DAC A VOUTB 2 15 A2 2 VOUTB Analog output voltage from DAC B VREFH 3 14 A1 3 VREFH Positive reference voltage input VDD 4 13 A0 4 VDD 5 VREFL Negative reference voltage input VREFL 5 6 GND Ground reference point for all circuitry on the part 7 VOUTC Analog output voltage from DAC C 8 VOUTD Analog output voltage from DAC D H/W synchronous VOUT update DAC8574 12 IOVDD GND 6 11 SDA VOUTC 7 10 SCL VOUTD 8 9 LDAC DESCRIPTION Analog voltage supply input 9 LDAC 10 SCL Serial clock input 11 SDA Serial data input 12 IOVDD 13 A0 Device address select - I2C 14 A1 Device address select - I2C 15 A2 Device address select - Extended 16 A3 Device address select - Extended I/O voltage supply input ABSOLUTE MAXIMUM RATINGS (1) VDD to GND -0.3 V to +6 V Digital input voltage to GND -0.3 V to VDD + 0.3 V VOUT to GND 0.3 V to VDD + 0.3 V Operating temperature range 40°C to +105°C Storage temperature range 65°C to +150°C Junction temperature range (TJ max) Power dissipation: Lead temperature, soldering: (1) 2 +150°C Thermal impedance (ΘJA) 118°C/W Thermal impedance (ΘJC) 29°C/W Vapor phase (60s) 215°C Infrared (15s) 220°C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to absolute maximum conditions for extended periods may affect device reliability. DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 ELECTRICAL CHARACTERISTICS VDD = 2.7 V to 5.5 V, RL = 2 kΩ to GND; CL = 200 pF to GND; all specifications -40°C to +105°C, unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS STATIC PERFORMANCE (1) (2) Resolution 16 Bits Relative accuracy Differential nonlinearity Specified monotonic by design Zero-scale error 5 Full-scale error -0.15 Gain error Zero code error drift Gain temperature coefficient PSRR VDD = 5 V ± 0.0987 % of FSR ±1 LSB 20 mV ±1.0 % of FSR ± 1.0 % of FSR ±7 µV/°C ±3 ppm of FSR/°C 0.75 mV/V OUTPUT CHARACTERISTICS (3) Output voltage range Output voltage settling time (full scale) 0 VREFH V 10 µs RL = 2 kΩ; 0 pF < CL < 200 pF 8 RL = 2 kΩ; CL = 500 pF 12 µs 1 V/µs Slew rate DC crosstalk 0.25 AC crosstalk Capacitive load stability Digital-to-analog glitch impulse -100 RL= ∞ 470 RL= 2 kΩ 1000 pF 1 LSB change around major carry 20 nV-s 0.5 nV-s 1 Ω VDD= 5 V 50 mA VDD= 3 V 20 mA Coming out of power-down mode, VDD= +5 V 2.5 µs Coming out of power-down mode, VDD= +3 V 5 µs Digital feedthrough DC output impedance Short-circuit current Power-up time LSB 1 kHz Sine Wave -96 dB pF REFERENCE INPUT VREFH Input range VREFL Input range 0 VREFL < VREFH 0 Reference input impedance Reference current LOGIC INPUTS VDD GND VDD 35 V V kΩ VREF=VDD= +5 V 135 180 VREF=VDD= +3 V 80 120 µA (3) Input current VIN_L, Input low voltage VIN_H, Input high voltage VDD= 3 V ±1 µA 0.3xIOVDD V 3 pF 5.5 V 0.7xIOVDD V Pin Capacitance POWER REQUIREMENTS VDD, IOVDD IDD(normal operation) (1) (2) (3) 2.7 Excluding load current IDD@ VDD=+3.6V to +5.5V VIH= IOVDDand VIL=GND 950 1600 µA IDD@ VDD =+2.7V to +3.6V VIH= IOVDDand VIL=GND 900 1500 µA Linearity tested using a reduced code range of 485 to 64714; output unloaded. VREFH = VDD - 0.1 V, VREFL = GND Specified by design and characterization, not production tested. 3 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 ELECTRICAL CHARACTERISTICS (continued) VDD = 2.7 V to 5.5 V, RL = 2 kΩ to GND; CL = 200 pF to GND; all specifications -40°C to +105°C, unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS IDD (all power-down modes) IDD@ VDD=+3.6V to +5.5V VIH= IOVDDand IOVIL=GND 0.2 1 µA IDD@ VDD =+2.7V to +3.6V VIH= VDDand VIL=GND 0.05 1 µA ILOAD= 2 mA, VDD= +5 V 93% +105 °C POWER EFFICIENCY IOUT/IDD TEMPERATURE RANGE Specified performance -40 TIMING CHARACTERISTICS VDD = 2.7 V to 5.5 V, RL = 2 kΩ to GND; all specifications -40°C to +105°C, unless otherwise specified. SYMBOL fSCL PARAMETER SCL clock frequency TEST CONDITIONS MAX UNITS Standard mode MIN 100 kHz Fast mode 400 kHz High-Speed Mode, CB = 100 pF max 3.4 MHz 1.7 MHz High-speed mode, CB = 400 pF max tBUF tHD; tSTA tLOW tHIGH tSU; tSTA tSU; tDAT tHD; tDAT Bus free time between a STOP and START condition Hold time (repeated) START condition LOW period of the SCL clock HIGH period of the SCL clock Setup time for a repeated START condition Data setup time Data hold time Standard mode 4.7 µs Fast mode 1.3 µs Standard mode 4.0 µs Fast mode 600 ns High-speed mode 160 ns Standard mode 4.7 µs Fast mode 1.3 µs High-speed mode, CB = 100 pF max 160 ns High-speed mode, CB = 400 pF max 320 ns Standard mode 4.0 µs Fast mode 600 ns High-Speed Mode, CB = 100 pF max 60 ns High-speed mode, CB = 400 pF max 120 ns Standard mode 4.7 µs Fast mode 600 ns High-speed mode 160 ns Standard mode 250 ns Fast mode 100 ns High-speed mode 10 Standard mode 0 3.45 µs 4 Rise time of SCL signal ns Fast mode 0 0.9 µs High-speed mode, CB = 100 pF max 0 70 ns High-speed mode, CB = 400 pF max 0 150 ns Standard mode tRCL TYP 1000 ns 20 + 0.1CB 300 ns High-speed mode, CB = 100 pF max 10 40 ns High-speed mode, CB = 400 pF max 20 80 ns Fast mode DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TIMING CHARACTERISTICS (continued) VDD = 2.7 V to 5.5 V, RL = 2 kΩ to GND; all specifications -40°C to +105°C, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN MAX UNITS 1000 ns 300 ns 10 80 ns 20 160 ns 300 ns Standard mode tRCL1 Rise time of SCL signal after a Fast mode repeated START condition and after an acknowledge BIT High-speed mode, CB = 100 pF max High-speed mode, CB = 400 pF max 20 + 0.1CB Standard mode tFCL Fall time of SCL signal Fast mode 20 + 0.1CB 300 ns High-speed mode, CB = 100 pF max 10 40 ns High-speed mode, CB = 400 pF max 20 80 ns 1000 ns Standard mode tRDA Rise time of SDA signal 20 + 0.1CB 300 ns High-speed mode, CB = 100 pF max Fast mode 10 80 ns High-speed mode, CB = 400 pF max 20 160 ns Standard mode tFDA tSU; tSTO Fall time of SDA signal Setup time for STOP condition CB Capacitive load for SDA and SCL tSP Pulse width of spike suppressed VNH VNL Noise margin at the HIGH level for each connected device (including hysteresis) Noise margin at the LOW level for each connected device (including hysteresis) TYP 300 ns 20 + 0.1CB 300 ns 10 80 ns High-speed mode, CB = 400 pF max 20 160 Standard mode 4.0 µs Fast mode 600 ns High-speed mode 160 ns Fast mode High-speed mode, CB = 100 pF max ns 400 pF Fast mode 50 ns High-speed mode 10 ns Standard mode Fast mode 0.2 VDD V 0.1 VDD V High-speed mode Standard mode Fast mode High-speed mode 5 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS At TA = +25°C, unless otherwise noted. 64 48 32 16 0 - 16 - 32 - 48 - 64 Channel A V DD = 5 V LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE LE - LSB LE - LSB LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE DLE - LSB 0 - 0.5 0 - 0.5 Digital Input Code Digital Input Code 64 48 32 16 0 - 16 - 32 - 48 - 64 Figure 1. Figure 2. LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE Channel C VDD = 5 V 64 48 32 16 0 - 16 - 32 - 48 - 64 Channel D VDD = 5 V DLE - LSB 1 0.5 0 - 0.5 0.5 0 - 0.5 -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH Digital Input Code Digital Input Code 64 48 32 16 0 - 16 - 32 - 48 - 64 Figure 3. Figure 4. LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE Channel A V DD = 2.7 V LE - LSB DLE - LSB LE - LSB 0.5 -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH 64 48 32 16 0 - 16 - 32 - 48 - 64 Channel B VDD = 2.7 V 1 DLE - LSB 1 DLE - LSB VDD = 5 V -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH 1 0.5 0 - 0.5 0.5 0 - 0.5 -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH Digital Input Code Digital Input Code Figure 5. 6 Channel B 1 0.5 LE - LSB LE - LSB DLE - LSB 1 64 48 32 16 0 - 16 - 32 - 48 - 64 Figure 6. DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. 64 48 32 16 0 - 16 - 32 - 48 - 64 Channel C VDD = 2.7 V LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE LE - LSB LE - LSB LINEARITY ERROR AND DIFFERENTIAL LINEARITY ERROR vs DIGITAL INPUT CODE 0.5 0 - 0.5 VDD = 2.7 V 0.5 0 - 0.5 -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH -1 0000 H 2000 H 4000 H 6000 H 8000 H A000 H C000H E000 H FFFFH Digital Input Code Digital Input Code Figure 7. Figure 8. ZERO-SCALE ERROR vs TEMPERATURE ZERO-SCALE ERROR vs TEMPERATURE 10 14 CH D 8 Zero -Scale Error - mV 12 Zero -Scale Error - mV Channel D 1 DLE - LSB DLE - LSB 1 64 48 32 16 0 - 16 - 32 - 48 - 64 CH A 10 CH B 8 6 CH C 4 CH D CH A 6 CH B 4 2 CH C 0 2 VDD = VREF = 2.7 V VDD = VREF = 5 V -2 0 - 40 - 10 20 50 80 - 40 110 - 10 TA - Free-Air Temperature - °C Figure 9. Figure 10. FULL-SCALE ERROR vs TEMPERATURE FULL-SCALE ERROR vs TEMPERATURE 15 110 15 To avoid clipping of the output signal during the test, VREF = VDD - 10 mV, V DD = 2.7 V, VREF = 2.69 V CH D 10 10 Full- Scale Error - mV Full- Scale Error - mV 20 50 80 TA - Free-Air Temperature - °C To avoid clipping of the output signal during the test, VREF = VDD - 10 mV, V DD = 5 V, VREF = 4.99 V 5 CH B 0 CH A -5 CH C - 10 CH A 0 CH B -5 CH C - 10 - 15 - 40 CH D 5 - 15 - 10 20 50 80 TA - Free-Air Temperature - °C Figure 11. 110 - 40 - 10 20 50 80 110 TA - Free-Air Temperature - °C Figure 12. 7 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. PULLDOWN CAPABILITY vs SINK CURRENT PULLDOWN CAPABILITY vs SINK CURRENT 0.15 0.15 Channel B 0.125 VOUT - Output Voltage - V VOUT - Output Voltage - V Channel A V DD = 2.7 V 0.1 0.075 VDD = 5 V 0.05 VREF = VDD - 10 mV 0.025 DAC Loaded With 0000 0.125 0.1 V DD = 2.7 V 0.075 VDD = 5 V 0.05 VREF = VDD - 10 mV 0.025 DAC Loaded With 0000 H 0 0 1 2 3 4 5 0 1 ISINK - Sink Current - mA 3 Figure 13. Figure 14. PULLDOWN CAPABILITY vs SINK CURRENT PULLDOWN CAPABILITY vs SINK CURRENT 5 Channel D VOUT - Output Voltage - V 0.125 0.1 V DD = 2.7 V 0.075 VDD = 5 V 0.05 VREF = VDD - 10 mV 0.025 DAC Loaded With 0000 0.125 0.1 V DD = 2.7 V 0.075 VDD = 5 V 0.05 VREF = VDD - 10 mV 0.025 DAC Loaded With 0000 H 0 H 0 0 1 2 3 4 5 0 1 ISINK - Sink Current - mA 2 3 4 5 ISINK - Sink Current - mA Figure 15. Figure 16. PULLUP CAPABILITY vs SOURCE CURRENT PULLUP CAPABILITY vs SOURCE CURRENT 5 5 Channel B VOUT - Output Voltage - V Channel A VOUT - Output Voltage - V 4 0.15 Channel C VOUT - Output Voltage - V 2 ISINK - Sink Current - mA 0.15 4.95 4.9 VREF = VDD - 10 mV DAC Loaded With FFFF H 4.85 4.95 4.9 VREF = VDD - 10 mV DAC Loaded With FFFF H 4.85 VDD = 5 V VDD = 5 V 4.8 4.8 0 1 2 3 ISOURCE - Source Current - mA Figure 17. 8 H 0 4 5 0 1 2 3 ISOURCE - Source Current - mA Figure 18. 4 5 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. PULLUP CAPABILITY vs SOURCE CURRENT PULLUP CAPABILITY vs SOURCE CURRENT 5 5 Channel D VOUT - Output Voltage - V VOUT - Output Voltage - V Channel C 4.95 4.9 VREF = VDD - 10 mV DAC Loaded With FFFF H 4.85 4.95 4.9 VREF = VDD - 10 mV DAC Loaded With FFFF H 4.85 VDD = 5 V VDD = 5 V 4.8 4.8 0 1 2 3 4 5 0 1 ISOURCE - Source Current - mA 2 3 Figure 19. Figure 20. PULLUP CAPABILITY vs SOURCE CURRENT PULLUP CAPABILITY vs SOURCE CURRENT 2.7 Channel B VOUT - Output Voltage - V VOUT - Output Voltage - V 5 2.7 Channel A 2.65 2.6 VREF = VDD - 10 mV DAC Loaded With FFFF H 2.55 2.65 2.6 VREF = VDD - 10 mV DAC Loaded With FFFF H 2.55 VDD = 2.7 V VDD = 2.7 V 2.5 2.5 0 1 2 3 4 5 0 1 ISOURCE - Source Current - mA 2 3 4 5 ISOURCE - Source Current - mA Figure 21. Figure 22. PULLUP CAPABILITY vs SOURCE CURRENT PULLUP CAPABILITY vs SOURCE CURRENT 2.7 2.7 Channel D VOUT - Output Voltage - V Channel C VOUT - Output Voltage - V 4 ISOURCE - Source Current - mA 2.65 2.6 VREF = VDD - 10 mV DAC Loaded With FFFF H 2.55 2.65 2.6 VREF = VDD - 10 mV DAC Loaded With FFFF H 2.55 VDD = 2.7 V VDD = 2.7 V 2.5 2.5 0 1 2 3 ISOURCE - Source Current - mA Figure 23. 4 5 0 1 2 3 4 5 ISOURCE - Source Current - mA Figure 24. 9 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. SUPPLY CURRENT vs DIGITAL INPUT CODE SUPPLY CURRENT vs TEMPERATURE 1200 1200 VDD = V REF = 5 V V DD = V REF = 5 V 1000 I DD - Supply Current -µ A I DD - Supply Current -µ A 1000 800 600 VDD = V REF = 2.7 V 400 200 0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 800 V DD = V Reference Current Included 200 0 - 40 20 - 10 80 50 110 TA - Free - Air Temperature - oC Figure 25. Figure 26. SUPPLY CURRENT vs SUPPLY VOLTAGE SUPPLY CURRENT vs LOGIC INPUT VOLTAGE 1750 µA 1000 - Supply Current - 950 900 850 800 TA = 25C, A0 Input (All Other Inputs = GND) Reference Current Included 1650 1550 1450 IOVDD = 5 V 1350 1250 1150 DD 750 I DD + IOI I DD - Supply Current -µ A = 2.7 V All Channels Powered, No Load 400 Digital Input Code 700 650 600 1050 VDD = VREF = 2.7 V 950 850 750 2.7 3.05 3.4 3.75 4.1 4.45 4.8 VDD - Supply Voltage - V Figure 27. 10 REF 600 5.15 5.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 VLOGIC - Logic Input Voltage - V Figure 28. 4.0 4.5 5.0 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. HISTOGRAM OF CURRENT CONSUMPTION HISTOGRAM OF CURRENT CONSUMPTION 1500 1500 V DD = V REF = 5 V Reference Current Included 1000 VDD = VREF = 2.7 V Reference Current Included I DD - Current Consumption - µA I DD VDD = VREF = 5 V Power- Up Code = FFFFH 2.52 2.51 VOUT (V, 10 mV/div) VOUT - Output Voltage - V 2.50 1060 1030 970 2.49 2.48 2.47 2.46 2.45 2.44 2.43 Time (1µs/div) Figure 32. OUTPUT GLITCH (Worst Case) VDD = VREF = 5 V Code EFFFH to F000H to EFFFH (Glitch Occurs Every N • 4096 Code Boundary) 4.66 4.64 4.62 4.60 ABSOLUTE ERROR 20 18 16 Output Error - mV VOUT (V, 20 mV/div) 1000 VDD = VREF = 5 V Code 7FFFH to 8000H to 7FFFH (Glitch Occurs Every N • 4096 Code Boundary) Figure 31. 4.68 940 OUTPUT GLITCH (Mid-Scale) 2.53 Time (4 µs/div) 4.70 µA Figure 30. EXITING POWER-DOWN MODE 4.72 910 - Current Consumption - Figure 29. 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 - 0.5 880 850 820 790 730 1120 1150 1090 1060 1030 1000 970 940 910 880 0 850 0 820 500 790 500 760 Frequency Frequency 1000 14 12 8 6 4 4.56 2 Time (1µs/div) Channel D Output Channel B Output 10 4.58 4.54 VDD = VREF = 5 V TA = 25°C Channel A Output Channel C Output 0 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH Digital Input Code Figure 33. Figure 34. 11 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. FULL-SCALE SETTLING TIME (Large Signal) ABSOLUTE ERROR 6 10 Output Error - mV 6 4 Channel B Output Channel D Output 2 0 -2 -4 -6 -8 Channel A Output VDD = VREF = 5.5 V Output Loaded with 2 kΩ and 200 pF to GND 5 VOUT - Output Voltage - V VDD = VREF = 2.7 V TA = 25°C 8 4 3 2 1 Channel C Output - 10 0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH 0 Time (12 µs/div) Digital Input Code Figure 35. Figure 36. HALF-SCALE SETTLING TIME (Large Signal) FULL-SCALE SETTLING TIME (Large Signal) VDD = VREF = 5 V Output Loaded with 2 kΩ and 200 pF to GND 2.5 2.0 1.5 1.0 0.5 3.5 VDD = VREF = 2.7 V Output Loaded with 2 kΩ and 200 pF to GND 3.0 VOUT - Output Voltage - V VOUT - Output Voltage - V 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 Time (12 µs/div) Time (12 µs/div) Figure 37. Figure 38. HALF-SCALE SETTLING TIME SIGNAL-TO-NOISE RATIO vs OUTPUT FREQUENCY 1.50 1.00 0.50 VDD = VREF = 2.7 V Output Loaded with 2 kΩ and 200 pF to GND SNR - Signal - to - Noise Ratio - dB VOUT - Output Voltage - V 98 96 VDD = 5 V 94 92 VDD = 2.7 V 90 88 VDD = VREF - 1 dB FSR Digital Input, F S = 52 ksps Measurement Bandwidth = 20 kHz 86 0.00 Time (12 µs/div) 84 0 500 1k 1.5k 2k 2.5k 3k f - Output Frequency - Hz Figure 39. 12 Figure 40. 3.5k 4k 4.5k DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, unless otherwise noted. TOTAL HARMONIC DISTORTION vs OUTPUT FREQUENCY TOTAL HARMONIC DISTORTION vs OUTPUT FREQUENCY 0 0 VDD = VREF = 5 V FS = 52 ksps, - 1 dB FSR Digital Input Measurement Bandwidth = 20 kHz - 30 - 40 THD - 50 - 60 - 70 - 80 3rd Harmonic - 90 VDD = VREF = 2.7 V FS = 52 ksps, - 1 dB FSR Digital Input Measurement Bandwidth = 20 kHz - 10 THD - T otal Harmonic Distortion - dB - 20 2nd Harmonic - 100 - 20 - 30 - 40 THD - 50 - 60 - 70 - 80 - 90 2nd Harmonic 3rd Harmonic -100 500 1k 1.5k 2k 2.5k 3k f - Output Frequency - Hz 3.5k 4k 0 500 1k 1.5k 2k 2.5k 3k f - Output Frequency - Hz 3.5k Figure 41. Figure 42. FULL-SCALE SETTLING TIME (Small-Signal-Positive Going Step) FULL-SCALE SETTLING TIME (Small-Signal-Negative Going Step) Small- Signal Settling Time 5mV/div Trigger Signal Time (2µs/div) Figure 43. Output Voltage 0 Output Voltage THD - T otal Harmonic Distortion - dB - 10 4k Small- Signal Settling Time 5mV/div Trigger Signal Time (2µs/div) Figure 44. 13 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 THEORY OF OPERATION D/A SECTION The architecture of the DAC8574 consists of a string DAC followed by an output buffer amplifier. Figure 45 shows a generalized block diagram of the DAC architecture. VREFH 50 k 50 k 70 k _ Ref+ Resistor String Ref- DAC Register + VOUT VREFL Figure 45. R-String DAC Architecture The input coding to the DAC8574 is unsigned binary, which gives the ideal output voltage as: V OUT VREFL (VREFH VREFL) D 65536 Where D = decimal equivalent of the binary code that is loaded to the DAC register; it can range from 0 to 65535. RESISTOR STRING The resistor string section is shown in Figure 46. It is basically a divide-by-2 resistor, followed by a string of resistors, each of value R. The code loaded into the DAC register determines at which node on the string the voltage is tapped off to be fed into the output amplifier by closing one of the switches connecting the string to the amplifier. Because the architecture consists of a string of resistors, it is specified monotonic. To Output Amplifier VREFH VREFL R R R R Figure 46. Typical Resistor String Output Amplifier The output buffer is a gain-of-2 noninverting amplifiers, capable of generating rail-to-rail voltages on its output, which gives an output range of 0V to VDD. It is capable of driving a load of 2 kΩ in parallel with 1000 pF to GND. The source and sink capabilities of the output amplifier can be seen in the typical curves. The slew rate is 1 V/µs with a half-scale settling time of 8 µs with the output unloaded. I2C Interface I2C is a 2-wire serial interface developed by Philips Semiconductor (see I2C-Bus Specification, Version 2.1, January 2000). The bus consists of a data line (SDA) and a clock line (SCL) with pullup structures. When the bus is idle, both SDA and SCL lines are pulled high. All the I2C compatible devices connect to the I2C bus through open drain I/O pins, SDA and SCL. A master device, usually a microcontroller or a digital signal processor, controls the bus. The master is responsible for generating the SCL signal and device addresses. The master also generates specific conditions that indicate the START and STOP of data transfer. A slave device receives and/or transmits data on the bus under control of the master device. 14 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 THEORY OF OPERATION (continued) The DAC8574 works as a slave and supports the following data transfer modes, as defined in the I2C-Bus Specification: standard mode (100 kbps), fast mode (400 kbps), and high-speed mode (3.4 Mbps). The data transfer protocol for standard and fast modes is exactly the same, therefore they are referred to as F/S-mode in this document. The protocol for high-speed mode is different from the F/S-mode, and it is referred to as HS-mode. The DAC8574 supports 7-bit addressing; 10-bit addressing, and general call address are not supported. F/S-Mode Protocol • • • • The master initiates data transfer by generating a start condition. The start condition is when a high-to-low transition occurs on the SDA line while SCL is high, as shown in Figure 47. All I2C-compatible devices should recognize a start condition. The master then generates the SCL pulses, and transmits the 7-bit address and the read/write direction bit R/W on the SDA line. During all transmissions, the master ensures that data is valid. A valid data condition requires the SDA line to be stable during the entire high period of the clock pulse (see Figure 48). All devices recognize the address sent by the master and compare it to their internal fixed addresses. Only the slave device with a matching address generates an acknowledge (see Figure 49) by pulling the SDA line low during the entire high period of the 9th SCL cycle. Upon detecting this acknowledge, the master knows that communication link with a slave has been established. The master generates further SCL cycles to either transmit data to the slave (R/W bit 1) or receive data from the slave (R/W bit 0). In either case, the receiver needs to acknowledge the data sent by the transmitter. So acknowledge signal can either be generated by the master or by the slave, depending on which one is the receiver. 9-bit valid data sequences consisting of 8-bit data and 1-bit acknowledge can continue as long as necessary. To signal the end of the data transfer, the master generates a stop condition by pulling the SDA line from low to high while the SCL line is high (see Figure 47). This releases the bus and stops the communication link with the addressed slave. All I2C compatible devices must recognize the stop condition. Upon the receipt of a stop condition, all devices know that the bus is released, and they wait for a start condition followed by a matching address. H/S-Mode Protocol • • • When the bus is idle, both SDA and SCL lines are pulled high by the pullup devices. The master generates a start condition followed by a valid serial byte containing H/S master code 00001XXX. This transmission is made in F/S-mode at no more than 400 Kbps. No device is allowed to acknowledge the H/S master code, but all devices must recognize it and switch their internal setting to support 3.4 Mbps operation. The master then generates a repeated start condition (a repeated start condition has the same timing as the start condition). After this repeated start condition, the protocol is the same as F/S-mode, except that transmission speeds up to 3.4 Mbps are allowed. A stop condition ends the H/S-mode and switches all the internal settings of the slave devices to support the F/S-mode. Instead of using a stop condition, repeated start conditions should be used to secure the bus in H/S-mode. SDA SDA SCL SCL S P Start Condition Stop Condition Figure 47. START and STOP Conditions 15 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 THEORY OF OPERATION (continued) SDA SCL Data Line Stable; Data Valid Change of Data Allowed Figure 48. Bit Transfer on the I2C Bus Data Output by Transmitter Not Acknowledge Data Output by Receiver Acknowledge SCL From Master 1 2 8 9 S Clock Pulse for Acknowledgement START Condition Figure 49. Acknowledge on the I2C Bus Recognize START or REPEATED START Condition Recognize STOP or REPEATED START Condition Generate ACKNOWLEDGE Signal P SDA MSB Acknowledgement Signal From Slave Sr Address R/W SCL S or Sr START or Repeated START Condition 1 2 7 8 9 ACK 1 3-8 9 ACK Sr or P Clock Line Held Low While Interrupts are Serviced STOP or Repeated START Condition Figure 50. Bus Protocol 16 2 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 2 DAC8574 I C Update Sequence The DAC8574 requires a start condition, a valid I2C address, a control byte, an MSB byte, and an LSB byte for a single update. After the receipt of each byte, DAC8574 acknowledges by pulling the SDA line low during the high period of a single clock pulse. A valid I2C address selects the DAC8574. The control byte sets the operational mode of the selected DAC8574. Once the operational mode is selected by the control byte, DAC8574 expects an MSB byte followed by an LSB byte for data update to occur. DAC8574 performs an update on the falling edge of the acknowledge signal that follows the LSB byte. Control byte needs not to be resent until a change in operational mode is required. The bits of the control byte continuously determine the type of update performed. Thus, for the first update, DAC8574 requires a start condition, a valid I2C address, a control byte, an MSB byte and an LSB byte. For all consecutive updates, DAC8574 needs an MSB byte and an LSB byte as long as the control command remains the same. Using the I2C high-speed mode (fscl= 3.4 MHz), the clock running at 3.4 MHz, each 16-bit DAC update other than the first update can be done within 18 clock cycles (MSB byte, acknowledge signal, LSB byte, acknowledge signal), at 188.88 KSPS. Using the fast mode (fscl= 400 kHz), clock running at 400 kHz, maximum DAC update rate is limited to 22.22 KSPS. Once a stop condition is received DAC8574 releases the I2C bus and awaits a new start condition. Address Byte MSB 1 LSB 0 0 1 1 A1 A0 R/W The address byte is the first byte received following the START condition from the master device. The first five bits (MSBs) of the address are factory preset to 10011. The next two bits of the address are the device select bits A1 and A0. The A1, A0 address inputs can be connected to VDD or digital GND, or can be actively driven by TTL/CMOS logic levels. The device address is set by the state of these pins during the power-up sequence of the DAC8574. Up to 16 devices (DAC8574) can still be connected to the same I2C-Bus. 17 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Broadcast Address Byte MSB LSB 1 0 0 1 0 0 0 0 Broadcast addressing is also supported by DAC8574. Broadcast addressing can be used for synchronously updating or powering down multiple DAC8574 devices. DAC8574 is designed to work with other members of the DAC857x and DAC757x families to support multichannel synchronous update. Using the broadcast address, DAC8574 responds regardless of the states of the address pins. Broadcast is supported only in write mode (Master writes to DAC8574). Control Byte MSB LSB A3 A2 L1 L0 X Sel1 Sel0 PD0 Table 1. Control Register Bit Descriptions Bit Name Extended Address Bit A2 Extended Address Bit L1 Load1 (Mode Select) Bit L2 Load0 (Mode Select) Bit The state of these bits must match the state of pins A3 and A2 in order for a proper DAC8574 data update, except in broadcast update mode. Are used for selecting the update mode. 00 Store I2C data. The contents of MS-BYTE and LS-BYTE (or power down information) are stored in the temporary register of a selected channel. This mode does not change the DAC output of the selected channel. 01 Update selected DAC with I2C data. Most commonly utilized mode. The contents of MS-BYTE and LS-BYTE (or power down information) are stored in the temporary register and in the DAC register of the selected channel. This mode changes the DAC output of the selected channel with the new data. 10 4-Channel synchronous update. The contents of MS-BYTE and LS-BYTE (or power down information) are stored in the temporary register and in the DAC register of the selected channel. Simultaneously, the other three channels get updated with previously stored data from the temporary register. This mode updates all four channels together. 11 Broadcast update mode. This mode has two functions. In broadcast mode, DAC8574 responds regardless of local address matching, and channel selection becomes irrelevant as all channels update. This mode is intended to enable up to 64 channels simultaneous update, if used with the I2C broadcast address (1001 0000). Sel1 Buff Sel1 Bit Sel0 Buff Sel0 Bit PD0 18 Bit Number/Description A3 If Sel1=0 All four channels are updated with the contents of their temporary register data. If Sel1=1 All four channels are updated with the MS-BYTE and LS-BYTE data or powerdown. Channel Select Bits 00 Channel A 01 Channel B 10 Channel C 11 Channel D Power Down Flag 0 Normal operation 1 Power-down flag (MSB7 and MSB6 indicate a power-down operation, as shown in Table 2). DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Table 2. Control Byte C7 C6 C5 C4 C3 C2 C1 C0 MSB7 MSB6 MSB5... A3 A2 Load1 Load0 Don't Care Ch Sel 1 Ch Sel 0 PD0 MSB (PD1) MSB-1 (PD2) MSB-2 ...LSB 0 0 X 0 0 0 Data Write to temporary register A (TRA) with data 0 0 X 0 1 0 Data Write to temporary register B (TRB) with data 0 0 X 1 0 0 Data Write to temporary register C (TRC) with data 0 0 X 1 1 0 Data Write to temporary register D (TRD) with data 0 0 X 0 1 X 0 1 X 1 0 X 1 0 X DESCRIPTION (Address Select) (A3 and A2 should correspond to the package address set via pins A3 and A2.) (00, 01, 10, or 11) 1 see Table 8 0 (00, 01, 10, or 11) 0 Write to TRx (selected by C2 &C1 and load DACx w/data Data (00, 01, 10, or 11) 1 see Table 8 0 (00, 01, 10, or 11) 0 see Table 8 Power-down DACx (selected by C2 and C1) Write to TRx (selected by C2 &C1 w/ data and load all DACs Data (00, 01, 10, or 11) 1 Write to TRx (selected by C2 &C1 w/Powerdown Command 0 Power-down DACx (selected by C2 and C1) & load all DACs Broadcast Modes (controls up to 4 devices on a single serial bus) X X 1 1 X 0 X X X Update all DACs, all devices with previously stored TRx data X X 1 1 X 1 X 0 Data Update all DACs, all devices with MSB[7:0] and LSB[7:0] data X X 1 1 X 1 X 1 see Table 8 0 Power-down all DACs, all devices Most Significant Byte Most Significant Byte MSB[7:0] consists of eight most significant bits of 16-bit unsigned binary D/A conversion data. C0=1, MSB[7], MSB[6] indicate a powerdown operation as shown in Table 8. Least Significant Byte Least Significant Byte LSB[7:0] consists of the 8 least significant bits of the 16bit unsigned binary D/A conversion data. DAC8574 updates at the falling edge of the acknowledge signal that follows the LSB[0] bit. Default Readback Condition If the user initiates a readback of a specified channel without first writing data to that specified channel, the default readback is all zeros, since the readback register is initialized to 0 during the power on reset phase. 19 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 LDAC Functionality Depending on the control byte, DACs are synchronously updated on the falling edge of the acknowledge signal that follows LS byte. The LDAC pin is required only when an external timing signal is used to update all the channels of the DAC asynchronously. LDAC is a positive edge triggered asynchronous input that allows four DAC output voltages to be updated simultaneously with temporary register data. The LDAC trigger should only be used after the buffers temporary registers are properly updated through software. DAC8574 Registers Table 3. DAC8574 Architecture Register Descriptions Register Description CTRL[7:0] Stores 8-bit wide control byte sent by the master MSB[7:0] Stores the 8 most significant bits of unsigned binary data sent by the master. Can also store 2-bit power-down data. LSB[7:0] Stores the 8 least significant bits of unsigned binary data sent by the master. TRA[17:0], TRB[17:0], TRC[17:0], TRD[17:0] 18-bit temporary storage registers assigned to each channel. Two MSBs store power-down information, 16 LSBs store data. DRA[17:0], DRB[17:0], DRC[17:0], DRD[17:0] 18-bit DAC registers for each channel. Two MSBs store power-down information, 16 LSBs store DAC data. An update of this register means a DAC update with data or power-down. DAC8574 as a Slave Receiver - Standard and Fast Mode Figure 51 shows the standard and fast mode master transmitter addressing a DAC8574 Slave Receiver with a 7-bit address. S SLAVE ADDRESS R/W A Ctrl-Byte A MS-Byte A LS-Byte ”0” (write) A/A P Data Transferred (n* Words + Acknowledge) Word = 16 Bit From Master to DAC8574 DAC8574 I2C-SLAVE ADDRESS: From DAC8574 to Master MSB A = A = S = Sr = P = Acknowledge (SDA LOW) Not Acknowledge (SDA HIGH) START Condition Repeated START Condition STOP Condition 1 LSB 0 0 1 1 A1 A0 R/W ‘0’ = Write to DAC8574 ‘1’ = Read from DAC8574 Factory Preset A0 = I2C Address Pin A1 = I2C Address Pin Figure 51. Standard and Fast Mode: Slave Receiver 20 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 DAC8574 as a Slave Receiver - High-Speed Mode Figure 52 shows the high-speed mode master transmitter addressing a DAC8574 Slave Receiver with a 7-bit address. F/S-Mode S HS-Mode HS-Master Code A Sr Slave Address F/S-Mode R/W A Ctrl-Byte A MS-Byte A LS-Byte Data Transferred (n* Words + Acknowledge) Word = 16 Bit ”0” (write) HS-Mode Master Code: P HS-Mode Continues Sr Slave Address MSB 0 A/A LSB 0 0 0 1 X X R/X Control Byte: MSB LSB A3 A2 L1 L0 X Sel1 Sel2 PD0 MS-Byte: MSB D15 LSB D14 D13 D12 D11 D10 D9 D5 D4 D3 D2 D1 D8 LS-Byte: MSB D7 LSB D6 D15 - D0 = Data Bits D0 A3 A2 L1 L0 Sel1 Sel0 PD0 = = = = = = = Extended Address Bit Extended Address Bit Load1 (Mode Select) Bit Load0 (Mode Select) Bit Buff Sel1 (Channel) Select Bit Buff Sel0 (Channel) Select Bit Power Down Flag X = Don’t Care Figure 52. High-Speed Mode: Slave Receiver 21 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Master Transmitter Writing to a Slave Receiver (DAC8574) in Standard/Fast Modes All write access sequences begin with the device address (with R/W = 0) followed by the control byte. This control byte specifies the operation mode of DAC8574 and determines which channel of DAC8574 is being accessed in the subsequent read/write operation. The LSB of the control byte (PD0-Bit) determines if the following data is power-down data or regular data. With (PD0-Bit = 0) the DAC8574 expects to receive data in the following sequence HIGH-BYTE –LOW-BYTE – HIGH-BYTE – LOW-BYTE..., until a STOP Condition or REPEATED START Condition on the I2C-Bus is recognized (refer to the DATA INPUT MODE section of Table 4). With (PD0-Bit = 1) the DAC8574 expects to receive 2 Bytes of power-down data (refer to the POWER DOWN MODE section of Table 4). Table 4. Write Sequence in F/S Mode DATA INPUT MODE Transmitter MSB 6 5 4 Master Master 1 0 0 1 DAC8574 Master A3 A2 Load 1 1 LSB 1 Comment A1 A0 R/W Write addressing (R/W=0) Buff Sel 0 PD0 Control byte (PD0=0) D9 D8 Writing data word, high byte D1 D0 Writing data word, low byte Begin sequence Load 0 x Buff Sel 1 DAC8574 Acknowledges D15 D14 D13 D7 D6 D5 DAC8574 Master 2 DAC8574 Acknowledges DAC8574 Master 3 Start D12 D11 D10 DAC8574 Acknowledges D4 DAC8574 D3 D2 DAC8574 Acknowledges Data or Stop or Repeated Start (1) Master Data or done (2) POWER DOWN MODE Transmitter MSB 6 5 4 Master Master 1 0 0 DAC8574 Master A3 A2 Load 1 PD1 PD2 0 1 1 A1 Load 0 x Comment A0 R/W Write addressing (R/W=0) Buff Sel 0 PD0 Control byte (PD0 = 1) 0 0 0 Writing data word, high byte 0 0 0 Writing data word, low byte Buff Sel 1 0 0 DAC8574 Acknowledges 0 0 0 0 0 DAC8574 Acknowledges Master Stop or Repeated Start (1) 22 LSB Begin sequence DAC8574 (1) (2) 1 DAC8574 Acknowledges DAC8574 Master 2 DAC8574 Acknowledges DAC8574 Master 3 Start Done Use repeated START to secure bus operation and loop back to the stage of write addressing for next Write. Once DAC8574 is properly addressed and control byte is sent, HIGH–BYTE–LOW–BYTE sequences can repeat until a STOP condition or repeated START condition is received. DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Master Transmitter Writing to a Slave Receiver (DAC8574) in HS Mode When writing data to the DAC8574 in HS-mode, the master begins to transmit what is called the HS-Master Code (0000 1XXX) in F/S-mode. No device is allowed to acknowledge the HS-Master Code, so the HS-Master Code is followed by a NOT acknowledge. The master then switches to HS-mode and issues a repeated start condition, followed by the address byte (with R/W = 0) after which the DAC8574 acknowledges by pulling SDA low. This address byte is usually followed by the control byte, which is also acknowledged by the DAC8574. The LSB of the control byte (PD0-Bit) determines if the following data is power-down data or regular data. With (PD0-Bit = 0) the DAC8574 expects to receive data in the following sequence HIGH-BYTE – LOW-BYTE – HIGH-BYTE – LOW-BYTE...., until a STOP condition or repeated start condition on the I2C-Bus is recognized (refer to Table 5 HS-MODE WRITE SEQUENCE - DATA). With (PD0-Bit = 1) the DAC8574 expects to receive 2 bytes of power-down data (refer to Table 5 HS-MODE WRITE SEQUENCE - POWER DOWN). Table 5. Master Transmitter Writes to Slave Receiver (DAC8574) in HS-Mode HS MODE WRITE SEQUENCE - DATA Transmitter MSB 6 5 4 0 0 0 0 Master Master 0 0 1 X X X Comment Begin sequence 1 HS Mode Master Code No device may acknowledge HS master code 1 A1 A0 R/W Write addressing (R/W=0) Buff Sel 0 PD0 Control byte (PD0=0) D9 D8 Writing data word, MSB D1 D0 Writing data word, LSB DAC8574 Acknowledges 0 0 Load 1 DAC8574 Load 0 0 Buff Sel 1 DAC8574 Acknowledges D15 D14 D13 D7 D6 D5 DAC8574 Master LSB Repeated Start 1 DAC8574 Master 1 Not Acknowledge Master Master 2 Start NONE Master 3 D12 D11 D10 DAC8574 Acknowledges D4 DAC8574 D3 D2 DAC8574 Acknowledges Data or Stop or Repeated Start (1) Master Data or done (2) HS MODE WRITE SEQUENCE - POWER DOWN Transmitter MSB 6 5 4 Master Master 3 2 0 0 0 0 1 X Not Acknowledge Master Repeated Start 1 0 0 DAC8574 Master 0 0 Load 1 PD1 PD2 0 1 X HS Mode Master Code No device may acknowledge HS master code A1 Load 2 0 A0 R/W Write addressing (R/W = 0) Buff Sel 0 PD0 Control Byte (PD0=1) 0 0 0 Writing data word, high byte 0 0 0 Writing data word, low byte Buff Sel 1 0 0 DAC8574 Acknowledges 0 0 0 0 0 DAC8574 DAC8574 Acknowledges Master Stop or repeated start (1) (1) (2) X DAC8574 Acknowledges DAC8574 Master 1 Comment DAC8574 Acknowledges DAC8574 Master LSB Begin sequence NONE Master 1 Start Done Use repeated start to secure bus operation and loop back to the stage of write addressing for next Write. Once DAC8574 is properly addressed and control byte is sent, high-byte-low-byte sequences can repeat until a stop or repeated start condition is received. 23 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 DAC8574 as a Slave Transmitter - Standard and Fast Mode Figure 53 shows the standard and fast mode master transmitter addressing a DAC8574 Slave Transmitter with a 7-bit address. (DAC8574) (DAC8574) (DAC8574) S SLAVE ADDRESS R/W A Ctrl <7:1> PD0 A Sr Slave Address ’0’ = (Normal Mode) Data Transferred (2 Bytes + Acknowledge) (DAC8574) PD0 A Sr Slave Address ’1’ = (Power Down Flag) (MASTER) R/W A PDN-Byte A (MASTER) (MASTER) MS-Byte A LS-Byte A P Data Transferred (3 Bytes + Acknowledge) ’1’ (read) PDN-Byte: MSB (MASTER) R/W A MS-Byte A LS-Byte A P ’1’ (read) ’0’ (write) (MASTER) LSB PD1 PD2 1 1 1 1 1 1 PD1 = Power-Down Bit PD2 = Power-Down Bit Figure 53. Standard and Fast Mode: Slave Transmitter DAC8574 as a Slave Transmitter - High-Speed Mode Figure 54 shows an I2C-Master addressing DAC8574 in high-speed mode (with a 7-bit address), as a Slave Transmitter. F/S-Mode HS-Master Code S A HS-Mode (DAC8574) Sr Slave Address (DAC8574) R/W A Ctrl <7:1> PD0 A Sr (DAC8574) Slave Address ’0’ = (Normal Mode) Data Transferred (2 Bytes + Acknowledge) (DAC8574) PD0 A Sr Slave Address ’1’ = (Power -Down Flag) (MASTER) R/W A PDN-Byte A ’1’ (read) Figure 54. High-Speed Mode: Slave Transmitter 24 (MASTER) R/W A MS-Byte A LS-Byte A P ’1’ (read) ’0’ (write) (MASTER) (MASTER) (MASTER) MS-Byte A LS-Byte A P Data Transferred (3 Bytes + Acknowledge) DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Master Receiver Reading From a Slave Transmitter (DAC8574) in Standard/Fast Modes When reading data back from the DAC8574, the user begins with an address byte (with R/W = 0) after which the DAC8574 will acknowledge by pulling SDA low. This address byte is usually followed by the Control Byte, which is also acknowledged by the DAC8574. Following this there is a REPEATED START condition by the Master and the address is resent with (R/W = 1). This is acknowledged by the DAC8574, indicating that it is prepared to transmit data. Two or three bytes of data are then read back from the DAC8574, depending on the (PD0-Bit). The value of Buff-Sel1 and Buff-Sel0 determines, which channel data is read back. A STOP Condition follows. With the (PD0-Bit = 0) the DAC8574 transmits 2 bytes of data, HIGH-BYTE followed by the LOW-BYTE (refer to Table 2. Data Readback Mode - 2 bytes). With the (PD0-Bit = 1) the DAC8574 transmits 3 bytes of data, POWER-DOWN-BYTE followed by the HIGH-BYTE followed by the LOW-BYTE (refer to Table 2. Data Readback Mode - 3 bytes). Table 6. Read Sequence in F/S Mode DATA READBACK MODE - 2 BYTES Transmitter MSB 6 5 4 1 0 0 1 3 Master Master A3 A2 Load 1 Comment A0 R/W Write addressing (R/W=0) Buff Sel 1 Buff Sel 0 PD0 Control byte (PD0=0) A1 A0 R/W Read addressing (R/W = 1) D10 D9 D8 Reading data word, high byte D2 D1 D0 Reading data word, low byte Begin sequence x DAC8574 Acknowledges Repeated Start 1 0 0 D15 D14 D13 DAC8574 1 1 DAC8574 Acknowledges Master DAC8574 A1 1 Load 0 Master DAC8574 LSB DAC8574 Acknowledges DAC8574 Master 1 Start DAC8574 Master 2 D12 D11 Master Acknowledges D7 D6 D5 D4 D3 Master Master Not Acknowledges Master signal end of read Master Stop or Repeated Start (1) Done DATA READBACK MODE - 3 BYTES Transmitter MSB 6 5 4 3 Master Master 1 0 0 1 A3 A2 Load 1 Load 0 DAC8574 Master 0 0 A1 A0 R/W Write addressing (R/W=0) Buff Sel 1 Buff Sel 0 PD0 Control byte (PD0=1) A1 A0 R/W Read addressing (R/W = 1) 1 1 1 D10 D9 D8 Reading data word, high byte D2 D1 D0 Reading data word, low byte Begin sequence 1 x 1 1 DAC8574 Acknowledges PD1 PD2 1 1 D15 D14 D13 D12 Master 1 Read power down byte Master Acknowledges Master DAC8574 Comment Repeated Start 1 DAC8574 DAC8574 LSB DAC8574 Acknowledges Master DAC8574 1 DAC8574 Acknowledges DAC8574 Master 2 Start D11 Master Acknowledges D7 D6 D5 D4 D3 Master Master Not Acknowledges Master signal end of read Master Stop or Repeated Start (1) Done (1) Use repeated start to secure bus operation and loop back to the stage of write addressing for next Write. 25 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Master Receiver Reading From a Slave Transmitter (DAC8574) in HS-Mode When reading data to the DAC8574 in HS-MODE, the master begins to transmit, what is called the HS-Master Code (0000 1XXX) in F/S-mode. No device is allowed to acknowledge the HS-Master Code, so the HS-Master Code is followed by a NOT acknowledge. The Master then switches to HS-mode and issues a REPEATED START condition, followed by the address byte (with R/W = 0) after which the DAC8574 acknowledges by pulling SDA low. This address byte is usually followed by the control byte, which is also acknowledged by the DAC8574. Then there is a REPEATED START condition initiated by the master and the address is resent with (R/W = 1). This is acknowledged by the DAC8574, indicating that it is prepared to transmit data. Two or Three bytes of data are then read back from the DAC8574, depending on the (PD0-Bit). The value of Buff-Sel1 and Buff-Sel0 determines, which channel data is read back. A STOP condition follows. With the (PD0-Bit = 0) the DAC8574 transmits 2 bytes of data, HIGH-BYTE followed by LOW-BYTE (refer to Table 7 HS-Mode Readback Sequence). With the (PD0-Bit = 1) the DAC8574 transmits 3 bytes of data, POWER-DOWN-BYTE followed by the HIGH-BYTE followed by the LOW-BYTE (refer to Table 7 HS-Mode Readback Sequence). Table 7. Master Receiver Reading Slave Transmitter (DAC8574) in HS-Mode HS MODE READBACK SEQUENCE Transmitter MSB 6 5 4 0 0 0 0 3 Master Master LSB Comment X X X HS Mode Master Code Begin sequence 1 No device may acknowledge HS master code Not Acknowledge Master Repeated Start 1 0 0 DAC8574 Master 1 Start NONE Master 2 1 1 A1 A3 A2 Load 1 Load 0 X Buff Sel 1 DAC8574 DAC8574 Acknowledges Master Repeated Start Master 1 0 0 DAC8574 DAC8574 PD1 PD2 1 26 Write addressing (R/W=0) Buff Sel 0 PD0 Control byte (PD0 = 1) 1 1 A1 A0 R/W Read addressing (R/W=1) 1 1 1 1 1 Power-down byte D9 D8 Reading data word, high byte D1 D0 Reading data word, low byte Master Acknowledges D15 D14 D13 Master DAC8574 R/W DAC8574 Acknowledges Master DAC8574 A0 DAC8574 Acknowledges D12 D11 D10 Master Acknowledges D7 D6 D5 D4 D3 D2 Master Master Not Acknowledges Master signal end of read Master Stop or Repeated Start Done DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Power-On Reset The DAC8574 contains a power-on-reset circuit that controls the output voltage during power up. On power up, the DAC register is filled with zeros and the output voltage is 0 V; it remains there until a valid write sequence is made to the DAC. This is useful in applications where it is important to know the state of the output of the DAC while it is in the process of powering up. No device pin should be brought high before supply is applied. Power-Down Modes The DAC8574 contains four separate power-down modes of operation. The modes are programmable via two most significant bits of the MSB byte, while (CTRL[0] = PD0 = 1). Table 8 shows how the state of these bits correspond to the mode of operation of the device. Table 8. Power-Down Modes of Operation for the DAC8574 CTRL[0] MSB[7] MSB[6] OPERATING MODE 1 0 0 High Impedance Output 1 0 1 1 kΩ to GND 1 1 0 100 kΩ to GND 1 1 1 High Impedance When (CTRL[0] = PD0 = 0), the device works normally with its normal power consumption of 250 µA at 5 V per channel. However, for the three power-down modes, the supply current falls to 200 nA at 5 V (50 nA at 3 V). Not only does the supply current fall but also the output stage is also internally switched from the output of the amplifier to a resistor network of known values. This has the advantage that the output impedance of the device is known while in power-down mode. There are three different options: The output is connected internally to GND through a 1-kΩ resistor, a 100 kΩ resistor or left open-circuit (high impedance). The output stage is illustrated in Figure 55. Amplifier Resistor String DAC VOUT Powerdown Circuitry Resistor Network Figure 55. Output Stage During Power Down All linear circuitry is shut down when the power-down mode is activated. However, the contents of the DAC register are unaffected when in power-down. The time to exit power down is typically 2.5 µs for VDD = 5 V and 5 µs for VDD = 3 V. (See the Typical Curves section for additional information.) The DAC8574 offers a flexible power-down interface based on channel register operation. A channel consists of a single 16-bit DAC with power-down circuitry, a temporary storage register (TR) and a DAC register (DR). TR and DR are both 18 bits wide. Two MSBs represent the power-down condition and the 16 LSBs represent data for TR and DR. By using bits 17 and 18 of TR and DR, a power-down condition can be temporarily stored and used just like data. Internal circuits ensure that MSB[7] and MSB[6] get transferred to TR[17] and TR[16] (DR[17] and DR[16]) when the power-down flag (CTRL[0] = PD0) is set. Therefore, DAC8574 treats power-down conditions like data and all the operational modes are still valid for power down. It is possible to broadcast a power-down condition to all the DAC8574s in the system, or it is possible to simultaneously power down a channel while updating data on other channels. 27 DAC8574 SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 www.ti.com CURRENT CONSUMPTION The DAC8574 typically consumes 225 µA at VDD = 5 V and 200 µA at VDD = 3 V for each active channel, including reference current consumption. Additional current consumption can occur at the digital inputs if VIH << VDD. For most efficient power operation, CMOS logic levels are recommended at the digital inputs to the DAC. In power-down mode, typical current consumption is 200 nA. A delay time of 10 to 20 ms after a power-down command is issued to the DAC is typically sufficient for the power-down current to drop below 10 µA. DRIVING RESISTIVE AND CAPACITIVE LOADS The DAC8574 output stage is capable of driving loads of up to 1000 pF while remaining stable. Within the offset and gain error margins, the DAC8574 can operate rail-to-rail when driving a capacitive load. Resistive loads of 2 kΩ can be driven by the DAC8574 while achieving very good load regulation. Load regulation error increases as the output voltage approaches each rail. When the outputs of the DAC are driven to the positive rail under resistive loading, the PMOS transistor of each Class-AB output stage can enter into the linear region. When this occurs, the added IR voltage drop deteriorates the linearity performance of the DAC. This only occurs within approximately the top 20 mV of the DAC's digital input-to-voltage output transfer characteristic. The reference voltage applied to the DAC8574 may be reduced below the supply voltage applied to VDD in order to eliminate this condition if good linearity is a requirement at full scale (under resistive loading conditions). CROSSTALK AND AC PERFORMANCE The DAC8574 architecture uses separate resistor strings for each DAC channel in order to achieve ultra-low crosstalk performance. DC crosstalk seen at one channel during a full-scale change on the neighboring channel is typically less than 0.5 LSBs. The ac crosstalk measured (for a full-scale, 1 kHz sine wave output generated at one channel, and measured at the remaining output channel) is typically under –100 dB. In addition, the DAC8574 can achieve typical ac performance of 96 dB signal-to-noise ratio (SNR) and 65 dB total harmonic distortion (THD), making the DAC8574 a solid choice for applications requiring high SNR at output frequencies at or below 4 kHz. OUTPUT VOLTAGE STABILITY The DAC8574 exhibits excellent temperature stability of ±3 ppm/°C typical output voltage drift over the specified temperature range of the device. This enables the output voltage of each channel to stay within a ±25 µV window for a ±1°C ambient temperature change. Good power-supply rejection ratio (PSRR) performance reduces supply noise present on VDD from appearing at the outputs to well below 10 µV-s. Combined with good dc noise performance and true 16-bit differential linearity, the DAC8574 becomes a perfect choice for closed-loop control applications. SETTLING TIME AND OUTPUT GLITCH PERFORMANCE Settling time to within the 16-bit accurate range of the DAC8574 is achievable within 10 µs for a full-scale code change at the input. Worst case settling times between consecutive code changes is typically less than 2 µs. The high-speed serial interface of the DAC8574 is designed in order to support up to 188ksps update rate. For full-scale output swings, the output stage of each DAC8574 channel typically exhibits less than 100 mV of overshoot and undershoot when driving a 200 pF capacitive load. Code-to-code change glitches are extremely low (~10 µV) given that the code-to-code transition does not cross an Nx4096 code boundary. Due to internal segmentation of the DAC8574, code-to-code glitches occur at each crossing of an Nx4096 code boundary. These glitches can approach 100mVs for N = 15, but settle out within ~2 µs. APPLICATION INFORMATION The following sections give example circuits and tips for using the DAC8574 in various applications. For more information, contact your local TI representative, or visit the Texas Instruments website at http://www.ti.com. BASIC CONNNECTIONS For many applications, connecting the DAC8574 is extremely simple. A basic connection diagram for the DAC8574 is shown in Figure 56. The 0.1 µF bypass capacitors help provide the momentary bursts of extra current needed from the supplies. 28 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 APPLICATION INFORMATION (continued) DAC8574 I2C Pullup Resistors 1 kΩ to 10 kΩ (typical) Microcontroller or Microprocessor With I2C Port IOVDD 1 VOUTA A3 16 2 VOUTB A2 15 3 VREFH A1 14 4 VDD A0 13 5 VREFL IOVDD 12 6 GND SDA 11 7 VOUTC SCL 10 8 VOUTD LDAC 9 SCL SDA NOTE: DAC8574 power and input/output connections are omitted for clarity, except IC Inputs. Figure 56. Typical DAC8574 Connections The DAC8574 interfaces directly to standard mode, fast mode and high-speed mode I2C controllers. Any microcontroller's I2C peripheral, including master-only and non-multiple-master I2C peripherals, work with the DAC8574. The DAC8574 does not perform clock-stretching (i.e., it never pulls the clock line low), so it is not necessary to provide for this unless other devices are on the same I2C bus. Pullup resistors are necessary on both the SDA and SCL lines because I2C bus drivers are open-drain. The size of the these resistors depend on the bus operating speed and capacitance on the bus lines. Higher-value resistors consume less power, but increase the transition times on the bus, limiting the bus speed. Lower-value resistors allow higher speed at the expense of higher power consumption. Long bus lines have higher capacitance and require smaller pullup resistors to compensate. If the pullup resistors are too small the bus drivers may not be able to pull the bus line low. USING GPIO PORTS FOR I2C Most microcontrollers have programmable input/output pins that can be set in software to act as inputs or outputs. If an I2C controller is not available, the DAC8574 can be connected to GPIO pins, and the I2C bus protocol simulated, or bit-banged, in software. An example of this for a single DAC8574 is shown in Figure 57. 29 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 APPLICATION INFORMATION (continued) DAC8574 IOVDD 1 VOUTA A3 16 2 VOUTB A2 15 3 VREFH A1 14 4 VDD A0 13 5 VREFL Microcontroller or Microprocessor IOVDD 12 6 GND SDA 11 7 VOUTC SCL 10 8 VOUTD LDAC 9 GPIO-1 GPIO-2 NOTE: DAC8574 power and input/output connections are omitted for clarity, except IC Inputs. Figure 57. Using GPIO With a Single DAC8574 Bit-banging I2C with GPIO pins can be done by setting the GPIO line to zero and toggling it between input and output modes to apply the proper bus states. To drive the line low, the pin is set to output a zero; to let the line go high, the pin is set to input. When the pin is set to input, the state of the pin can be read; if another device is pulling the line low, this reads as a zero in the port's input register. Note that no pullup resistor is shown on the SCL line. In this simple case the resistor is not needed. The microcontroller can simply leave the line on output, and set it to one or zero as appropriate. It can do this because the DAC8574 never drives its clock line low. This technique can also be used with multiple devices, and has the advantage of lower current consumption due to the absence of a resistive pullup. If there are any devices on the bus that may drive their clock lines low, the above method should not be used. The SCL line should be high-Z or zero, and a pullup resistor provided as usual. Note also that this cannot be done on the SDA line in any case, because the DAC8574 drives the SDA line low from time to time, as all I2C devices do. Some microcontrollers have selectable strong pullup circuits built in to their GPIO ports. In some cases, these can be switched on and used in place of an external pullup resistor. Weak pullups are also provided on some microcontrollers, but usually these are too weak for I2C communication. Test any circuit before committing it to production. 30 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 APPLICATION INFORMATION (continued) USING REF02 AS A POWER SUPPLY FOR DAC8574 Due to the extremely low supply current required by the DAC8574, a possible configuration is to use a REF02 +5 V precision voltage reference to supply the required voltage to the DAC8574's supply input as well as the reference input, as shown in Figure 58. This is especially useful if the power supply is quite noisy or if the system supply voltages are at some value other than 5 V. The REF02 outputs a steady supply voltage for the DAC8574. If the REF02 is used, the current it needs to supply to the DAC8574 is 950 µA typical and 1600 µA max for VDD = 5 V. When a DAC output is loaded, the REF02 also needs to supply the current to the load. The total typical current required (with a 5-kΩ load on a single DAC output) is: 950 µA + (5 V / 5 kΩ) = 1.950 mA The load regulation of the REF02 is typically 0.005%/mA, which results in an error of 488µV for 1.950-mA of current drawn from it. This corresponds to a 6.4 LSB error for a 0-V to 5-V output range. 15 V REF02 5V 950 A I2C Interface SCL SDA VDD, Vref DAC8574 VOUT = 0 V to 5 V Figure 58. REF02 Power Supply REF3040 can also be used to generate a 4.096-V reference from a 5-V supply. 31 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 GENERATING ±5-V, ±10-V, and ± 12-V OUTPUTS FOR PRECISION INDUSTRIAL CONTROL Industrial control applications can require multiple feedback loops consisting of sensors, ADCs, MCUs, DACs, and actuators. Loop accuracy and loop speed are the two important parameters of such control loops. Loop Accuracy: In a control loop, the ADC has to be accurate. Offset, gain, and the integral linearity errors of the DAC are not factors in determining the accuracy of the loop. As long as a voltage exists in the transfer curve of a monotonic DAC, the loop can find it and settle to it. On the other hand, DAC resolution and differential linearity do determine the loop accuracy, because each DAC step determines the minimum incremental change the loop can generate. A DNL error less than -1 LSB (non-monotonicity) can create loop instability. A DNL error greater than +1 LSB implies unnecessarily large voltage steps, and missed voltage targets. With high DNL errors, the loop looses its stability, resolution, and accuracy. Offering 16-bit assured monotonicity and ± 0.25 LSB typical DNL error, 85XX DACs are great choices for precision control loops. Loop Speed: Many factors determine control loop speed. Typically, the ADC's conversion time, and the MCU's computation time are the two major factors that dominate the time contstant of the loop. DAC settling time is rarely a dominant factor because ADC conversion times usually exceed DAC conversion times. DAC offset, gain, and linearity errors can slow the loop down only during the start-up. Once the loop reaches its steady-state operation, these errors do not affect loop speed any further. Depending on the ringing characteristics of the loop's transfer function, DAC glitches can also slow the loop down. With its 188 ksps maximum data update rate, DAC8574 can support high-speed control loops. Generating Industrial Voltage Ranges: For control loop applications, DAC gain and offset errors are not important parameters. This could be exploited to lower trim and calibration costs in a high-voltage control circuit design. Using a quad op amp (OPA4130), a voltage reference (REF3040) and a quad 12-bit DAC (DAC7574), the DAC8574 can generate the wide voltage swings required by the control loop. Vtail DAC7574 R1 REF3040 R2 Vref VREFH DAC8574 _ Vdac + VOUT OPA4130 Figure 59. Low-cost, Wide-swing Voltage Generator for Control Loop Applications The output voltage of the configuration is given by: Din –V R2 V out V ref R2 1 65536 tail R1 R1 Fixed R1 and R2 resistors can be used to coarsely set the gain required in the first term of the equation. Once R2 an R1 set the gain properly, a DAC7574 could be used to set the required offset voltages. Residual errors are not an issue for loop accuracy because offset and gain errors could be tolerated. For ±5-V operation: R1=10 kΩ, R2 = 15 kΩ, Vtail = 3.33 V, Vref = 4.096 V For ±10-V operation: R1=10 kΩ, R2 = 39 kΩ, Vtail = 2.56 V, Vref = 4.096 V For ±12-V operation: R1=10 kΩ, R2 = 49 kΩ, Vtail = 2.45 V, Vref = 4.096 V 32 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Digital Correction of DAC Errors For open-loop applications requiring improved accuracy, offset and gain errors of the DAC8574 can be measured and digitally corrected. To avoid waveform clipping, it is recommended to make the offset and gain error measurements at codes 1024 and 64512 respectively. The total error of DAC8574 is dominated by gain and offset errors, and it can be improved by an order of magnitude using the following digital correction: DIN = DDIN – OE – (FSE – OE) × (DDIN – 1024) ÷ 64512 where: DIN = Digital input code to the DAC after offset and gain correction DDIN = Digital input code to the DAC before offset and gain correction OE = measured DAC error at code 1024 (in LSBs) FSE = measured DAC error at code 64512 (in LSBs) If division operation is not feasible, FSE measurement can be done at code 32768 instead of code 64512. Division by 32768 implies a 15-bit arithmetic right shift. Improvements to the transfer curve are still significant. DAC8574 integral linearity error is well within ±5 mV, therefore it only has a secondary effect on total DAC error. Using piece-wise linear approximation, and non-volatile memory, integral linearity errors of DAC8574 can also be digitally corrected. Consult TI applications engineering for details. 64 Channel Operation DAC8574 is designed to facilitate high channel count operation. DAC8574 supports multichannel simultaneous synchronous update up to 16 DAC8574 devices for up to 64 channels on a single I2C bus. Working with multiple DAC8574s, single channel DAC8571s can be used on the same bus to obtain odd channel counts, or quad channel DAC7574s can be used if some channels only need 12 bits of resolution. Data or power down can be loaded to temporary registers of each channel serially and a single broadcast operation can be used to update all channels of all devices simultaneously with previously stored data or power-down condition. Another feature useful for system start-up or system shut-down is to broadcast the same data (or power-down condition) to all channels with a single broadcast command. All multichannel system updates are performed at the falling edge of the acknowledge signal that follows the least significant byte. The 64-channel operation requires 6-bit address decoding. 4-bit address decoding is used to support 16 DAC8574 devices on the same bus and 2-bit address decoding is used to select one out of four channels of a DAC8574. 4-bit address decoding that selects one out of 16 DAC8574 devices is done as follows: To save I2C address space, 2-bits (A0 and A1) are used for I2C address decoding, and two additional bits (A2 and A3) are used for local address decoding. Up to 4 DAC8574 devices using the same I2C address can be connected on the same I2C bus. These four devices with the same I2C address can be locally decoded using A2 and A3 pins. If multiple devices use the same I2C address, multiple devices acknowledge at the same time. However, in order for a particular device to respond to a command, the states of the first two bits of the control word C7 and C6 must match the states of A3 and A2 pins. Four devices per I2C address and four distinct I2C addresses enable 16 devices on the same bus. The four address pins should be set at power-up, and address bits must be set to match a particular device’s address pins. To decode up to 16 DAC8574 devices, the logic states of A3, A2, A1, A0 address pins and C7, C6, A1, A0 address bits should be set as shown in Table 9. 33 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 Table 9. 64 Channel Address Decoding DEV # A3 PIN C7 BIT A2 PIN C6 BIT A1 PIN A1 BIT A0 PIN A0 BIT 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 1 3 0 0 0 0 1 1 0 0 4 0 0 0 0 1 1 1 1 5 0 0 1 1 0 0 0 0 6 0 0 1 1 0 0 1 1 7 0 0 1 1 1 1 0 0 8 0 0 1 1 1 1 1 1 9 1 1 0 0 0 0 0 0 10 1 1 0 0 0 0 1 1 11 1 1 0 0 1 1 0 0 12 1 1 0 0 1 1 1 1 13 1 1 1 1 0 0 0 0 14 1 1 1 1 0 0 1 1 15 1 1 1 1 1 1 0 0 16 1 1 1 1 1 1 1 1 Once a DAC8574 device is selected, channel select bits C2 and C1 can select a particular channel. Overall, I2C address bits A1, A0, control bits C7, C6, C2 and C1 form the 6-bit address required to select one channel out of 64 possibilities. Broadcast operation is supported for both I2C addressing and for extended addressing. A broadcast address (10010000) makes all DAC8574 devices listen, regardless of the states of A0 and A1 pins. Also, a broadcast command (C5 = C4 = 1) makes all devices listen, regardless of the states of A2 and A3 pins. The same broadcast command (C5 = C4 = 1) also selects all channels for a given device, regardless of the states of channel select bits. Thus, a global broadcast message that simultaneously updates up to 64 channels uses 10010000 as I2C address and has (C5 = C4 = 1) in the control word. Examples I2C Standard and Fast Mode Examples (A0, A1, A2, A3 and LDAC pins tied to GND): EXAMPLE 1: WRITE 1/4 SCALE TO CHANNEL A ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0000 M [7...0] ACK 0100 0000 L [7...0] ACK 0000 0000 Previous VoutA output voltage is valid ACK STOP VoutA = 1.25 V EXAMPLE 2: WRITE 1/2 SCALE TO CHANNEL B ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0010 M [7...0] ACK 1000 0000 L [7...0] ACK 0000 0000 Previous VoutB output voltage is valid ACK STOP VoutB = 2.50 V EXAMPLE 3: WRITE 3/4 SCALE TO CHANNEL C ADDRESS [7...0] START 1001 1000 C [7...0] ACK Previous VoutC output voltage is valid 34 0001 0100 M [7...0] ACK 1100 0000 L [7...0] ACK 0000 0000 ACK STOP VoutC = 3.75 V DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 EXAMPLE 4: WRITE 4/4 SCALE TO CHANNEL D ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0110 M [7...0] ACK 1111 1111 L [7...0] ACK 1111 1111 Previous VoutD output voltage is valid ACK STOP VoutB = 5.0 V EXAMPLE 5: Power-Down Channel A, With Hi-Z Output ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0001 M [7...0] ACK 0000 0000 L [7...0] ACK 0000 0000 Previous VoutA output voltage is valid ACK STOP VoutA = Hi-Z EXAMPLE 6: Power-Down Channel B, With Hi-Z Output ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0011 M [7...0] ACK 0000 0000 L [7...0] ACK 0000 0000 Previous VoutB output voltage is valid ACK STOP VoutB = Hi-Z EXAMPLE 7: Power-Down Channel C, With Hi-Z Output ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0101 M [7...0] ACK 0000 0000 L [7...0] ACK 0000 0000 Previous VoutC output voltage is valid ACK STOP VoutC = Hi-Z EXAMPLE 8: Power-Down Channel D, With Hi-Z Output ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0111 M [7...0] ACK 0000 0000 L [7...0] ACK 0000 0000 Previous VoutD output voltage is valid ACK STOP VoutD = Hi-Z EXAMPLE 9: Power-Down Channel D, With 1 kΩ Output Impedance to Ground ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0001 0111 M [7...0] ACK 0100 0000 L [7...0] ACK 0000 0000 Previous VoutA output voltage is valid ACK STOP VoutD = 0 V EXAMPLE 10: Power-Down Channel D, With 100 kΩ Output Impedance to Ground ADDRESS [7...0] START 1001 1000 C [7...0] ACK Previous VoutD output voltage is valid 0001 0111 M [7...0] ACK 1000 0000 L [7...0] ACK 0000 0000 ACK STOP VoutD = 0 V 35 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 EXAMPLE 11: Simultaneous Update of All Channels Write 4/4 Scale, 4/3 Scale, 2/4 Scale, and 1/4 Scale Data to Temporary Registers of Channels A, B, C, D Serially, and Update all DACs Simultaneously ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0000 0000 M [7...0] L [7...0] ACK 1111 1111 ACK 1111 1111 ACK ACK 1100 0000 ACK 0000 0000 ACK ACK 1000 0000 ACK 0000 0000 ACK ACK 0100 0000 ACK 0000 0000 STOP Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0010 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0100 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0010 0110 Previous DAC output voltages are valid for all channels ACK New data is valid EXAMPLE 12: Simultaneous Update Channels A, B, C and Power-Down of Channel D at The End of The Fourth Cycle Write 4/4 Scale, 3/4 Scale, 2/4 Scale, and Power-Down (Hi-Z) Data to Temporary Registers of Channels A, B, C, D Serially, and Update Simultaneously ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0000 0000 M [7...0] L [7...0] ACK 1111 1111 ACK 1111 1111 ACK STOP ACK 1100 0000 ACK 0000 0000 ACK STOP ACK 1000 0000 ACK 0000 0000 ACK STOP ACK 0000 0000 ACK 0000 0000 ACK STOP Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0010 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0100 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0010 0111 Previous DAC output voltages are valid for all channels New data is valid EXAMPLE 13: Store data and wait for update command (Write codes 128, 256, 512, and 1024 to temporary registers of channels A, B, C, D) Write 4/4 Scale, 3/4 Scale, 2/4 Scale, and 1/4 Scale Data to Temporary Registers of Channels A, B, C, D Serially, and Update all DACs Simultaneously ADDRESS [7...0] START 1001 1000 C [7...0] ACK 0000 0000 M [7...0] L [7...0] ACK 0000 0000 ACK 1000 0000 ACK STOP ACK 0000 0001 ACK 0000 0000 ACK STOP ACK 0000 0010 ACK 0000 0000 ACK STOP ACK 0100 0100 ACK 0000 0000 ACK STOP Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0010 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0000 0100 Previous DAC output voltages are valid for all channels START 1001 1000 ACK 0010 0110 Previous DAC output voltages are valid for all channels 36 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 EXAMPLE 14: Broadcast update command. All channels of all DAC8574s update with previously stored temporary register data. ADDRESS [7...0] START 1001 0000 C [7...0] ACK M [7...0] 0011 0000 ACK XXXX XXXX L [7...0] ACK XXXX XXXX Previous DAC output voltages are valid for all channels, all DAC8574s ACK STOP New data is valid EXAMPLE 15: Broadcast Data. All channels of all DAC8574s get set to code 7. START ADDRESS [7...0] C [7...0] 1001 0000 0011 0000 ACK M [7...0] ACK L [7...0] 0000 0000 ACK 0000 0111 ACK STOP All Vouts = 7 x 76 µV Previous DAC output voltages are valid for all channels, all DAC8574s EXAMPLE 16: Broadcast Power-Down. All channels of all DAC8574s get powered down with output impedance of 1 kΩ to ground. ADDRESS [7...0] START C [7...0] 1001 0000 ACK M [7...0] 0011 0001 ACK L [7...0] 0100 0000 ACK 0000 0000 Previous DAC output voltages are valid for all channels, all DAC8574s ACK STOP All Vouts = GND I2C Read-back Examples (A0, A1, A2, A3 and LDAC pins tied to GND): EXAMPLE 17: Read back channel A power-down bits and 16-bit channel A data. V denotes valid logic. ADDRESS [7...0] START 1001 1000 PWD [7...0] MASTER VV11 1111 ACK C [7...0] ACK MSB [7...0] VVVV VVVV 0001 0001 MASTER ACK ACK REPEATED ADDRESS START 1001 1001 LSB [7...0] MASTER VVVV VVVV NOT ACK ACK EXAMPLE 18: Read back channel B power-down bits and 16-bit channel B data. V denotes valid logic. ADDRESS [7...0] START 1001 1000 PWD [7...0] MASTER VV11 1111 ACK C [7...0] ACK MSB [7...0] VVVV VVVV 0001 0011 MASTER ACK ACK REPEATED ADDRESS START 1001 1001 LSB [7...0] MASTER VVVV VVVV NOT ACK ACK EXAMPLE 19: Read back channel C power-down bits and 16-bit channel C data. V denotes valid logic. ADDRESS [7...0] START 1001 1000 PWD [7...0] MASTER VV11 1111 ACK C [7...0] ACK MSB [7...0] VVVV VVVV 0001 0101 MASTER ACK ACK REPEATED ADDRESS START 1001 1001 LSB [7...0] MASTER VVVV VVVV NOT ACK ACK EXAMPLE 20: Read back channel D power-down bits and 16-bit channel D data. V denotes valid logic. ADDRESS [7...0] START 1001 1000 PWD [7...0] MASTER VV11 1111 ACK C [7...0] ACK MSB [7...0] VVVV VVVV 0001 0111 MASTER ACK ACK REPEATED ADDRESS START 1001 1001 LSB [7...0] MASTER VVVV VVVV NOT ACK ACK EXAMPLE 21: Read back 16-bit channel D data only. V denotes valid logic. ADDRESS [7...0] START 1001 1000 MSB [7...0] MASTER VVVV VVVV ACK C [7...0] ACK 0001 0110 ACK LSB [7...0] MASTER VVVV VVVV NOT ACK REPEATED ADDRESS START 1001 1001 ACK 37 DAC8574 www.ti.com SLAS377B – JANUARY 2003 – REVISED DECEMBER 2004 I2C High Speed Examples (A0, A1, A2, A3 and LDAC pins tied to GND): EXAMPLE 22: Ramp generation on channel D (Up to Code 7 is shown) START HS Master Code NOT REPEATED ADDRESS 0000 1000 ACK START 10011 0000 C [7 … 0] ACK 0001 0110 ACK Previous VoutD voltage valid MSB [7…0] 0000 0000 LSB [7…0] ACK 0000 0000 Previous VoutD voltage valid MSB [7…0]] 0000 0000 ACK 0000 0010 0000 0000 ACK 0000 0001 ACK LSB [7…0] ACK 0000 0100 VoutD = 3 x 76 µV 0000 0000 LSB [7…0] ACK 0000 0011 MSB [7…0] VoutD = 5 x 76 µV 0000 0000 LSB [7…0] ACK 0000 0101 VoutD = 4 x 76 µV LSB [7…0] ACK 0000 0110 VoutD = 6 x 76 µV ACK VoutD = 5 x 76 µV MSB [7…0] ACK ACK VoutD = 3 x 76 µV MSB [7…0] ACK ACK VoutD = 76 µV MSB 7…0] VoutD = 2 x 76 µV MSB [7…0] 0000 0000 ACK LSB [7…0] VoutD = 0 V LSB [7…0] VoutD = 76 µV 0000 0000 MSB [7…0] 0000 0000 LSB [7…0] ACK 0000 0111 ACK VoutD = 7 x 76 µV LAYOUT A precision analog component requires careful layout, adequate bypassing, and clean, well-regulated power supplies. The power applied to VDD should 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 as their internal logic switches states. This noise can easily couple into the DAC output voltage through various paths between the power connections and analog output. As with the GND connection, VDD should be connected to a positive power-supply plane or trace that is separate from the connection for digital logic until they are connected at the power-entry point. In addition, a 1 µF to 10 µF capacitor in parallel with a 0.1 µF bypass capacitor is strongly recommended. In some situations, additional bypassing may be required, such as a 100 µF electrolytic capacitor or even a Pi filter made up of inductors and capacitors—all designed to essentially low-pass filter the –5 V supply, removing the high-frequency noise. 38 PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) DAC8574IPW ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 105 D8574I DAC8574IPWG4 ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 105 D8574I DAC8574IPWR ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 105 D8574I DAC8574IPWRG4 ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM -40 to 105 D8574I (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) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. 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Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device DAC8574IPWR Package Package Pins Type Drawing TSSOP PW 16 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2000 330.0 12.4 Pack Materials-Page 1 6.9 B0 (mm) K0 (mm) P1 (mm) 5.6 1.6 8.0 W Pin1 (mm) Quadrant 12.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DAC8574IPWR TSSOP PW 16 2000 367.0 367.0 35.0 Pack Materials-Page 2 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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