AD8300

a FEATURES Complete 12-Bit DAC No External Components Single +3 Volt Operation 0.5 mV/Bit with 2.0475 V Full Scale 6 s Output Voltage Settling Time Low Power: 3.6 mW Compact SO-8 1.5 mm Height Package APPLICATIONS Portable Communications Digitally Controlled Calibration Servo Controls PC Peripherals CLR LD CS CLK SDI +3 Volt, Serial Input Complete 12-Bit DAC AD8300 FUNCTIONAL BLOCK DIAGRAM 12-BIT DAC 12 DAC REGISTER 12 EN SERIAL REGISTER VDD REF VOUT GND AD8300 GENERAL DESCRIPTION The AD8300 is a complete 12-bit, voltage-output digital-toanalog converter designed to operate from a single +3 volt supply. Built using a CBCMOS process, this monolithic DAC offers the user low cost, and ease-of-use in single-supply +3 volt systems. Operation is guaranteed over the supply voltage range of +2.7 V to +5.5 V making this device ideal for battery operated applications. The 2.0475 V full-scale voltage output is laser trimmed to maintain accuracy over the operating temperature range of the device. The binary input data format provides an easy-to-use one-half-millivolt-per-bit software programmability. The voltage outputs are capable of sourcing 5 mA. 3.0 MINIMUM SUPPLY VOLTAGE – Volts A double buffered serial data interface offers high speed, threewire, DSP and microcontroller compatible inputs using data in (SDI), clock (CLK) and load strobe (LD) pins. A chip select (CS) pin simplifies connection of multiple DAC packages by enabling the clock input when active low. Additionally, a CLR input sets the output to zero scale at power on or upon user demand. The AD8300 is specified over the extended industrial (–40°C to +85°C) temperature range. AD8300s are available in plastic DIP, and low profile 1.5 mm height SO-8 surface mount packages. 1.00 2.8 INL LINEARITY ERROR – LSB VFS 1 LSB DATA = FFFH TA = +25 C 0.75 0.50 0.25 0.00 –0.25 –0.50 –0.75 VDD = +2.7V TA = –40 C, +25 C, +125 C 2.6 PROPER OPERATION WHEN VDD SUPPLY VOLTAGE ABOVE CURVE 2.4 2.2 2.0 0.01 = –40 C = +25 C = +125 C 0 1024 2048 3072 DIGITAL INPUT CODE – Decimal 4096 0.1 1.0 OUTPUT LOAD CURRENT – mA 10 –1.00 Figure 1. Minimum Supply Voltage vs. Load Figure 2. Linearity Error vs. Digital Code and Temperature REV. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 1999 AD8300–SPECIFICATIONS +3 V OPERATION (@ V Parameter STATIC PERFORMANCE Resolution Relative Accuracy Differential Nonlinearity2 Zero-Scale Error Full-Scale Voltage3 Full-Scale Tempco ANALOG OUTPUT Output Current (Source) Output Current (Sink) Load Regulation Output Resistance to GND Capacitive Load LOGIC INPUTS Logic Input Low Voltage Logic Input High Voltage Input Leakage Current Input Capacitance INTERFACE TIMING SPECIFICATIONS4, 5 Clock Width High Clock Width Low Load Pulsewidth Data Setup Data Hold Clear Pulsewidth Load Setup Load Hold Select Deselect AC CHARACTERISTICS4 Voltage Output Settling Time Output Slew Rate DAC Glitch Digital Feedthrough SUPPLY CHARACTERISTICS Power Supply Range Positive Supply Current Power Dissipation Power Supply Sensitivity DD = +5 V 10%, –40 C ≤ TA ≤ +85 C, unless otherwise noted) Condition [Note 1] Monotonic Data = 000H Data = FFFH [Notes 3, 4] Data = 800H, ∆VOUT = 5 LSB Data = 800H, ∆VOUT = 5 LSB RL = 200 Ω to ∞, Data = 800H Data = 000H No Oscillation4 Min 12 –2 –1 Typ Max Units Bits LSB LSB mV Volts ppm/°C mA mA LSB Ω pF V V µA pF Symbol N INL DNL VZSE VFS TCVFS IOUT IOUT LREG ROUT CL VIL VIH IIL CIL ± 1/2 ± 1/2 +1/2 2.039 2.0475 16 +2 +1 +3 2.056 1.5 30 500 5 2 5 0.6 2.1 10 10 tCH tCL tLDW tDS tDH tCLRW tLD1 tLD2 tCSS tCSH tS SR To ± 0.2% of Full Scale To ± 1 LSB of Final Value6 Data = 000H to FFFH to 000H 40 40 50 15 15 40 15 40 40 40 7 14 2.0 15 15 2.7 1.2 1.9 3.6 0.001 5.5 1.7 3.0 5.1 0.005 ns ns ns ns ns ns ns ns ns ns µs µs V/µs nV/s nV/s V mA mA mW %/% VDD RANGE IDD PDISS PSS DNL < ± 1 LSB VDD = 3 V, VIL = 0 V, Data = 000H VDD = 3.6 V, VIH = 2.3 V, Data = FFFH VDD = 3 V, VIL = 0 V, Data = 000H ∆VDD = ± 5% NOTES 1 LSB = 0.5 mV for 0 V to +2.0475 V output range. 2 The first two codes (000 H, 001H) are excluded from the linearity error measurement. 3 Includes internal voltage reference error. 4 These parameters are guaranteed by design and not subject to production testing. 5 All input control signals are specified with t R = tF = 2 ns (10% to 90% of +3 V) and timed from a voltage level of 1.6 V. 6 The settling time specification does not apply for negative going transitions within the last 6 LSBs of ground. Some devices exhibit double the typical settling time in this 6 LSB region. Specifications subject to change without notice. –2– REV. A AD8300 +5 V OPERATION Parameter STATIC PERFORMANCE Resolution Relative Accuracy Differential Nonlinearity2 Zero-Scale Error Full-Scale Voltage3 Full-Scale Tempco ANALOG OUTPUT Output Current (Source) Output Current (Sink) Load Regulation Output Resistance to GND Capacitive Load LOGIC INPUTS Logic Input Low Voltage Logic Input High Voltage Input Leakage Current Input Capacitance INTERFACE TIMING SPECIFICATIONS4, 5 Clock Width High Clock Width Low Load Pulsewidth Data Setup Data Hold Clear Pulsewidth Load Setup Load Hold Select Deselect AC CHARACTERISTICS4 Voltage Output Settling Time Output Slew Rate DAC Glitch Digital Feedthrough SUPPLY CHARACTERISTICS Power Supply Range Positive Supply Current Power Dissipation Power Supply Sensitivity (@ VDD = +5 V 10%, –40 C ≤ TA ≤ +85 C, unless otherwise noted) Condition [Note 1] Monotonic Data = 000H Data = FFFH [Notes 3, 4] Data = 800H, ∆VOUT = 5 LSB Data = 800H, ∆VOUT = 5 LSB RL = 200 Ω to ∞, Data = 800H Data = 000H No Oscillation4 Min 12 –2 –1 Typ Max Units Bits LSB LSB mV Volts ppm/°C mA mA LSB Ω pF V V µA pF Symbol N INL DNL VZSE VFS TCVFS IOUT IOUT LREG ROUT CL VIL VIH IIL CIL ± 1/2 ± 1/2 +1/2 2.039 2.0475 16 +2 +1 +3 2.056 1.5 30 500 5 2 5 0.8 2.4 10 10 tCH tCL tLDW tDS tDH tCLWR tLD1 tLD2 tCSS tCSH tS SR To ± 0.2% of Full Scale To ± 1 LSB of Final Value6 Data = 000H to FFFH to 000H 30 30 30 15 15 30 15 30 30 30 6 13 2.2 15 15 2.7 1.2 2.8 6 0.001 5.5 1.7 4.0 5.1 0.006 ns ns ns ns ns ns ns ns ns ns µs µs V/µs nV/s nV/s V mA mA mW %/% VDD RANGE IDD PDISS PSS DNL < ± 1 LSB VDD = 5 V, VIL = 0 V, Data = 000H VDD = 5.5 V, VIH = 2.3 V, Data = FFFH VDD = 5 V, VIL = 0 V, Data = 000H ∆VDD = ± 10% NOTES 1 1 LSB = 0.5 mV for 0 V to +2.0475 V output range. 2 The first two codes (000 H, 001H) are excluded from the linearity error measurement. 3 Includes internal voltage reference error. 4 These parameters are guaranteed by design and not subject to production testing. 5 All input control signals are specified with t R = tF = 2 ns (10% to 90% of +5 V) and timed from a voltage level of 1.6 V. 6 The settling time specification does not apply for negative going transitions within the last 6 LSBs of ground. Some devices exhibit double the typical settling time in this 6 LSB region. Specifications subject to change without notice. REV. A –3– AD8300 ABSOLUTE MAXIMUM RATINGS * VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V, +7 V Logic Inputs to GND . . . . . . . . . . . . . . . . . . . . . –0.3 V, +7 V VOUT to GND . . . . . . . . . . . . . . . . . . . . . . –0.3 V, VDD + 0.3 V IOUT Short Circuit to GND . . . . . . . . . . . . . . . . . . . . . . 50 mA Package Power Dissipation . . . . . . . . . . . . . (TJ Max – TA)/θJA Thermal Resistance θJA 8-Lead Plastic DIP Package (N-8) . . . . . . . . . . . . . 103°C/W 8-Lead SOIC Package (SO-8) . . . . . . . . . . . . . . . . 158°C/W Maximum Junction Temperature (TJ Max) . . . . . . . . . . 150°C Operating Temperature Range . . . . . . . . . . . . –40°C to +85°C Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . . +300°C *Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. PIN CONFIGURATIONS SO-8 Plastic DIP 1 4 8 5 VDD 1 CS 2 8 VOUT AD8300 7 GND (Not to Scale) CLK 3 TOP VIEW 6 CLR SDI 4 5 LD PIN DESCRIPTIONS Pin # 1 2 Name VDD CS Function Positive power supply input. Specified range of operation +2.7 V to +5.5 V. Chip Select, active low input. Disables shift register loading when high. Does not affect LD operation. Clock input, positive edge clocks data into shift register. Serial Data Input, input data loads directly into the shift register, MSB first. Load DAC register strobes, active low. Transfers shift register data to DAC register. See Truth Table I for operation. Asynchronous active low input. Resets DAC register to zero condition. Asynchronous active low input. Analog and Digital Ground. DAC voltage output, 2.0475 V full scale with 0.5 mV per bit. An internal temperature stabilized reference maintains a fixed full-scale voltage independent of time, temperature and power supply variations. D2 D1 D0 3 4 CLK SDI LD ORDERING GUIDE 5 Package Options N-8 SO-8 6 7 8 Model AD8300AN AD8300AR INL ±2 ±2 Temp XIND XIND Package Description 8-Lead P-DIP 8-Lead SOIC CLR GND VOUT NOTES XIND = –40°C to +85°C. The AD8300 contains 630 transistors. The die size measures 72 mil × 65 mil. SDI CLK D11 D10 D9 D8 D7 D6 D5 D4 D3 t CSS t CSH t LD2 CS t LD1 LD SDI t DS t DH t CH CLK LD CLR FS t CL t LDW t CLRW tS tS 1LSB ERROR BAND VOUT ZS Figure 3. Timing Diagram CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD8300 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. WARNING! ESD SENSITIVE DEVICE –4– REV. A Typical Performance Characteristics–AD8300 80 LOGIC THRESHOLD VOLTAGE 2.5 60 OUTPUT CURRENT – mA 40 20 0 –20 –40 –60 –80 0 POSITIVE CURRENT LIMIT VDD = +5V VDD = +3V TA = –40 TO +85 C 2.0 1.5 DATA = 800H RL TIED TO +1.024V 1.0 VDD = +3V VDD = +5V NEGATIVE CURRENT LIMIT 2 0.5 0 HORIZONTAL = 1 s/DIV 0 2 3 1 4 5 VDD SUPPLY VOLTAGE – Volts 6 1 OUTPUT VOLTAGE – Volts Figure 4. IOUT vs. VOUT Figure 5. Logic Input Threshold Voltage vs. VDD Figure 6. Detail Settling Time 50 POWER SUPPLY REJECTION – dB BROADBAND NOISE – 200 V/DIV 45 40 35 30 25 20 15 10 5 0 10 TA = +25 C DATA = FFFH VDD = +3V 10% VDD = +5V 10% TIME = 100 s/DIV HORIZONTAL = 20 s/DIV 100 10k 100k 1k FREQUENCY – Hz 1M Figure 7. Broadband Noise Figure 8. Power Supply Rejection vs. Frequency Figure 9. Large Signal Settling Time 3.5 3.0 SUPPLY CURRENT – mA 2.5 VDD = +3V 2.0 1.5 1.0 0.5 0 TA = +25 C DATA = FFFH CODE 800H TO 7FFH 0.5 s/DIV VDD = +5V 0 1 2 3 4 LOGIC VOLTAGE – Volts 5 Figure 10. Supply Current vs. Logic Input Voltage Figure 11. Midscale Transition Performance Figure 12. Digital Feedthrough vs. Time REV. A –5– AD8300 60 50 40 30 20 10 0 TUE = INL+ZS+FS ss = 300 UNITS VDD = +3V TA = +25 C 1.5 1.0 VOUT DRIFT – mV 0.5 VDD = +5V 0 –0.5 –1.0 –1.5 –55 –35 –15 NO LOAD ss = 300 UNITS NORMALIZED TO +25 C 3.0 VDD = +5.5V IDD SUPPLY CURRENT – mA 2.6 VDD = +5.0V FREQUENCY 2.2 VDD = +4.5V 1.8 VDD = +2.7, 3.0, 3.3V 1.4 DATA = FFFH VIH = +2.4V VIL = 0V –20 20 60 100 TEMPERATURE – C 140 VDD = +2.7V –1 0 1 2 3 4 5 6 TOTAL UNADJUSTED ERROR – mV 5 25 45 65 85 105 125 TEMPERATURE – C 1.0 –60 Figure 13. Total Unadjusted Error Histogram Figure 14. Zero-Scale Voltage Drift vs. Temperature Figure 15. Supply Current vs. Temperature 1.5 1.0 NO LOAD ss = 300 UNITS NORMALIZED TO +25 C VDD = +5.5V 0 –0.5 VDD = +2.7V –1.0 –1.5 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE – C 10 VDD = +3V DATA = FFFH FREQUENCY 70 60 50 VDD = +3V DATA FFFH TA = –40 TO +85 C NOISE DENSITY – V/Hz VOUT DRIFT – mV 0.5 1 40 30 20 10 0.1 0.01 1 10 100 1k FREQUENCY – Hz 10k 100k 0 –50 –40 –30 –20 –10 0 10 20 30 40 TEMPERATURE COEFFICIENT – ppm/ C Figure 16. Full-Scale Voltage Drift vs. Temperature Figure 17. Output Voltage Noise Density vs. Frequency Figure 18. Full-Scale Output Tempco Histogram 2.4 NOMINAL VOLTAGE CHANGE – mV 2.0 1.6 1.2 0.8 0.4 ZERO SCALE (DATA = 000H) 0 0 100 200 300 400 500 600 HOURS OF OPERATION AT +150 C FULL SCALE (DATA = FFFH) VDD = +2.7V ss = 135 UNITS Figure 19. Long Term Drift Accelerated by Burn-In –6– REV. A AD8300 Table I. Control Logic Truth Table CS H L L L ↑ H H H H CLK X L H ↑ L X X X X CLR H H H H H H H L ↑ LD H H H H H ↓ L X H Serial Shift Register Function No Effect No Effect No Effect Shift-Register-Data Advanced One Bit No Effect No Effect No Effect No Effect No Effect DAC Register Function Latched Latched Latched Latched Latched Updated with Current Shift Register Contents Transparent Loaded with All Zeros Latched All Zeros NOTES 1. ↑ = Positive Logic Transition; ↓ = Negative Logic Transition; X = Don’t Care. 2. Do not clock in serial data while LD is LOW. 3. Data loads MSB first. OPERATION OUTPUT SECTION The AD8300 is a complete ready to use 12-bit digital-to-analog converter. Only one +3 V power supply is necessary for operation. It contains a 12-bit laser-trimmed digital-to-analog converter, a curvature-corrected bandgap reference, rail-to-rail output op amp, serial-input register, and DAC register. The serial data interface consists of a serial-data-input (SDI) clock (CLK), and load strobe pins (LD) with an active low CS strobe. In addition an asynchronous CLR pin will set all DAC register bits to zero causing the VOUT to become zero volts. This function is useful for power on reset or system failure recovery to a known state. D/A CONVERTER SECTION The rail-to-rail output stage of this amplifier has been designed to provide precision performance while operating near either power supply. Figure 21 shows an equivalent output schematic of the rail-to-rail amplifier with its N-channel pull-down FETs that will pull an output load directly to GND. The output sourcing current is provided by a P-channel pull-up device that can source current to GND terminated loads. VDD P-CH N-CH VOUT The internal DAC is a 12-bit device with an output that swings from GND potential to 0.4 volt generated from the internal bandgap voltage, see Figure 20. It uses a laser-trimmed segmented R-2R ladder which is switched by N-channel MOSFETs. The output voltage of the DAC has a constant resistance independent of digital input code. The DAC output is internally connected to the rail-to-rail output op amp. AMPLIFIER SECTION AGND Figure 21. Equivalent Analog Output Circuit The internal DAC’s output is buffered by a low power consumption precision amplifier. This low power amplifier contains a differential PNP pair input stage that provides low offset voltage and low noise, as well as the ability to amplify the zero-scale DAC output voltages. The rail-to-rail amplifier is configured with a gain of approximately five in order to set the 2.0475 volt full-scale output (0.5 mV/LSB). See Figure 20 for an equivalent circuit schematic of the analog section. BANDGAP 1.2V REF 0.4V 0.4V FS The rail-to-rail output stage achieves the minimum operating supply voltage capability shown in Figure 2. The N-channel output pull-down MOSFET shown in Figure 21 has a 35 Ω on resistance which sets the sink current capability near ground. In addition to resistive load driving capability, the amplifier has also been carefully designed and characterized for up to 500 pF capacitive load driving capability. REFERENCE SECTION The internal curvature-corrected bandgap voltage reference is laser trimmed for both initial accuracy and low temperature coefficient. Figure 18 provides a histogram of total output performance of full-scale vs. temperature which is dominated by the reference performance. POWER SUPPLY 12-BIT DAC VOUT 2.047V FS R2 R1 Figure 20. Equivalent AD8300 Schematic of Analog Portion The very low power consumption of the AD8300 is a direct result of a circuit design optimizing use of a CBCMOS process. By using the low power characteristics of the CMOS for the logic, and the low noise, tight matching of the complementary bipolar transistors, good analog accuracy is achieved. For power-consumption sensitive applications it is important to note that the internal power consumption of the AD8300 is strongly dependent on the actual logic input voltage levels present on the SDI, CLK, CS, LD, and CLR pins. Since these inputs are standard CMOS logic structures, they contribute static power dissipation dependent on the actual driving logic The op amp has a 2 µs typical settling time to 0.4% of full scale. There are slight differences in settling time for negative slewing signals versus positive. Also negative transition settling time to within the last 6 LSB of zero volts has an extended settling time. See the oscilloscope photos in the typical performances section of this data sheet. REV. A –7– AD8300 VOH and VOL voltage levels. Consequently, for optimum dissipation use of CMOS logic versus TTL provides minimal dissipation in the static state. A VINL = 0 V on the logic input pins provides the lowest standby dissipation of 1.2 mA with a +3.3 V power supply. As with any analog system, it is recommended that the AD8300 power supply be bypassed on the same PC card that contains the chip. Figure 8 shows the power supply rejection versus frequency performance. This should be taken into account when using higher frequency switched-mode power supplies with ripple frequencies of 100 kHz and higher. One advantage of the rail-to-rail output amplifiers used in the AD8300 is the wide range of usable supply voltage. The part is fully specified and tested over temperature for operation from +2.7 V to +5.5 V. If reduced linearity and source current capability near full scale can be tolerated, operation of the AD8300 is possible down to +2.1 volts. The minimum operating supply voltage versus load current plot in Figure 2 provides information for operation below VDD = +2.7 V. TIMING AND CONTROL Table II. Unipolar Code Table Hexadecimal Number in DAC Register FFF 801 800 7FF 000 Decimal Number in DAC Register 4095 2049 2048 2047 0 Analog Output Voltage (V) C1968a–0–5/99 45 +2.0475 +1.0245 +1.0240 +1.0235 +0.0000 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 8-Lead SOIC (SO-8) 0.1968 (5.00) 0.1890 (4.80) 8 5 4 The AD8300 has a separate serial-input register from the 12-bit DAC register that allows preloading of a new data value MSB first into the serial register without disturbing the present DAC output voltage value. Data can only be loaded when the CS pin is active low. After the new value is fully loaded in the serialinput register, it can be asynchronously transferred to the DAC register by strobing the LD pin. The DAC register uses a level sensitive LD strobe that should be returned high before any new data is loaded into the serial-input register. At any time the contents of the DAC resister can be reset to zero by strobing the CLR pin which causes the DAC output voltage to go to zero volts. All of the timing requirements are detailed in Figure 3 along with Table I. Control Logic Truth Table. All digital inputs are protected with a Zener type ESD protection structure (Figure 22) that allows logic input voltages to exceed the VDD supply voltage. This feature can be useful if the user is loading one or more of the digital inputs with a 5 V CMOS logic input voltage level while operating the AD8300 on a +3.3 V power supply. If this mode of interface is used, make sure that the VOL of the +5 V CMOS meets the VIL input requirement of the AD8300 operating at 3 V. See Figure 5 for the effect on digital logic input threshold versus operating VDD supply voltage. VDD LOGIC IN GND 0.1574 (4.00) 0.1497 (3.80) PIN 1 1 0.2440 (6.20) 0.2284 (5.80) 0.0500 (1.27) BSC 0.0098 (0.25) 0.0040 (0.10) SEATING PLANE 0.0688 (1.75) 0.0532 (1.35) 0.0192 (0.49) 0.0138 (0.35) 8 0.0098 (0.25) 0 0.0075 (0.19) 0.0196 (0.50) 0.0099 (0.25) 0.0500 (1.27) 0.0160 (0.41) 8-Lead Plastic DIP (N-8) 0.430 (10.92) 0.348 (8.84) 8 5 0.280 (7.11) 0.240 (6.10) 0.325 (8.25) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.130 (3.30) MIN 15 0 0.015 (0.381) 0.008 (0.204) 1 4 PIN 1 0.100 (2.54) BSC 0.210 (5.33) MAX 0.160 (4.06) 0.115 (2.93) 0.015 (0.381) TYP 0.022 (0.558) 0.070 (1.77) SEATING 0.014 (0.356) 0.045 (1.15) PLANE Figure 22. Equivalent Digital Input ESD Protection Unipolar Output Operation This is the basic mode of operation for the AD8300. The AD8300 has been designed to drive loads as low as 400 Ω in parallel with 500 pF. The code table for this operation is shown in Table II. APPLICATIONS INFORMATION See DAC8512 data sheet for additional application circuit ideas. –8– REV. A PRINTED IN U.S.A.