® DAC DAC8043 804 3 CMOS 12-Bit Serial Input Multiplying DIGITAL-TO-ANALOG CONVERTER FEATURES APPLICATIONS ● 12-BIT ACCURACY IN 8-PIN SOIC ● AUTOMATIC CALIBRATION ● FAST 3-WIRE SERIAL INTERFACE ● MOTION CONTROL ● LOW INL AND DNL: ±1/2 LSB max ● MICROPROCESSOR CONTROL SYSTEMS ● GAIN ACCURACY TO ±1LSB max ● PROGRAMMABLE AMPLIFIER/ ATTENUATORS ● DIGITALLY CONTROLLED FILTERS ● LOW GAIN TEMPCO: 5ppm/°C max ● OPERATES WITH +5V SUPPLY ● TTL/CMOS COMPATIBLE ● ESD PROTECTED DESCRIPTION The DAC8043 is a 12-bit current output multiplying digital-to-analog converter (DAC) that is packaged in a space-saving, surface-mount 8-pin SOIC. Its 3-wire serial interface saves additional circuit board space which results in low power dissipation. When used with microprocessors having a serial port, the DAC8043 minimizes the digital noise feedthrough from its input to output. The serial port can be used as a dedicated analog bus and kept inactive while the DAC8043 is in use. Serial interfacing reduces the complexity of opto or transformer isolation applications. The DAC8043 contains a 12-bit serial-in, parallel-out shift register, a 12-bit DAC register, a 12-bit CMOS DAC, and control logic. Serial input (SRI) data is clocked into the input register on the rising edge of the clock (CLK) pulse. When the new data word had been clocked in, it is loaded into the DAC register by taking the LD input low. Data in the DAC register is converted to an output current by the D/A converter. RFB VREF 1 12-Bit D/A Converter 2 3 RFB IOUT 12 5 LD 12-Bit DAC Register 8 VDD 12 4 7 CLK 6 SRI GND 12-Bit Input Shift Register The DAC8043 operates from a single +5V power supply which makes the DAC8043 an ideal low power, small size, high performance solution for several applications. International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ® © 1993 Burr-Brown Corporation PDS-1197B 1 Printed in U.S.A. March, 1998 DAC8043 SPECIFICATIONS ELECTRICAL CHARACTERISTICS At VDD = +5V; VREF = +10V; IOUT = GND = 0V; TA = Full Temperature Range specified under Absolute Maximum Ratings, unless otherwise noted. DAC8043U PARAMETER SYMBOL STATIC PERFORMANCE Resolution Nonlinearity(1) Differential Nonlinearity(2) Gain Error(3) Gain Tempco(5) Power Supply Rejection Ratio Output Leakage Current(4) N INL DNL FSE IZSE Input Resistance RIN AC PERFORMANCE Output Current Settling Time(5, 6) Digital-to-Analog Glitch Energy(5, 10) MIN ANALOG OUTPUTS Output Capacitance(5) MAX ±0.0006 11 ±1 ±1 ±2 ±2 ±5 ±0.002 ±5 ±100 0.03 0.60 15 ∆VDD = ±5% T A = +25°C TA = Full Temp Range T A = +25°C TA = Full Temp Range 7 tS 0.25 2 0.7 VIH VIL IIL CIN TYP MAX UNITS ±0.0006 11 ±1/2 ±1/2 ±1 ±2 ±5 ±0.002 ±5 ±25 0.03 0.15 15 Bits LSB LSB LSB LSB ppm/°C %/% nA nA LSB LSB kΩ 1 20 0.25 2 1 20 µs nVs 1 0.7 1 mVp-p –85 17 dB 17 nV/√Hz VIN = 0V to +5V VIN = 0V 0.8 ±1 8 0.8 ±1 8 V V µA pF Digital Inputs = VIH Digital Inputs = VIL 110 80 110 80 pF pF TIMING CHARACTERISTICS(5, 14) Data Setup Time Data Hold Time Clock Pulse Width High Clock Pulse Width Low Load Pulse Width LSB Clock into Input Register to Load DAC Register Time tDS tDH tCH tCL tLD TA TA TA TA TA tASB TA = Full Temperature Range POWER SUPPLY Supply Voltage Supply Current VDD IDD = = = = = 7 –85 2.4 COUT MIN 12 T A = +25°C TA = Full Temp Range T A = +25°C VREF = 0V Q IOUT = Load = 100Ω CEXT = 13pF DAC Register Loaded Alternately with all 0s and all 1s Feedthrough Error(5, 11) FT VREF = 20Vp-p at f = 10kHz (VREF to IOUT) Digital Input = 0000 0000 0000 T A = +25°C Total Harmonic Distortion(5) THD VREF = 6VRMS at 1kHz DAC Register Loaded with all 1s Output Noise Voltage Density(5, 13) eN 10Hz to 100kHz Between RFB and IOUT DIGITAL INPUTS Digital Input High Digital Input Low Input Leakage Current(9) Input Capacitance(5, 11) DAC8043UC TYP 12 TCFSE PSRR ILKG Zero Scale Error(7, 12) (8) CONDITIONS Full Full Full Full Full Temperature Temperature Temperature Temperature Temperature Range Range Range Range Range 2.4 40 80 90 120 120 40 80 90 120 120 ns ns ns ns ns 0 0 ns 4.75 Digital Inputs = VIH or VIL Digital Inputs = 0V or VDD 5 5.25 500 100 4.75 5 5.25 500 100 V µA µA NOTES: (1) ±1/2 LSB = ±0.012% of Full Scale. (2) All grades are monotonic to 12-bits over temperature. (3) Using internal feedback resistor. (4) Applies to IOUT; All digital inputs = 0V. (5) Guaranteed by design and not tested. (6) IOUT Load = 100Ω, CEXT = 13pF, digital input = 0V to VDD or VDD to 0V. Extrapolated to 1/2 LSB: tS = propagation delay (tPD) + 9τ where τ = measured time constant of the final RC decay. (7) VREF = +10V, all digital inputs = 0V. (8) Absolute temperature coefficient is less than ±50ppm/°C. (9) Digital inputs are CMOS gates: IIN is typically 1nA at +25°C. (10) VREF = 0V, all digital inputs = 0V to VDD or VDD to 0V. (11) All digital inputs = 0V. (12) Calculated from worst case RREF: IZSE (in LSBs) = (RREF X ILKG X 4096)/VREF. (13) Calculations from en = √4K TRB where: K = Boltzmann constant, J/°K, R = resistance, Ω. T = Resistor temperature, °K, B = bandwidth, Hz. (14) Tested at VIN = 0V or VDD. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® DAC8043 2 WAFER TEST LIMITS At VDD = +5V; VREF = +10V; IOUT = GND = 0V; TA = +25°C. PARAMETER CONDITIONS LIMIT DAC8043 UNITS Using Internal Feedback Resistor ∆VDD = ±5% Digital Inputs = VIL 12 ±1 ±1 ±2 ±0.002 ±5 Bits min LSB max LSB max LSB max %/% max nA max SYMBOL STATIC ACCURACY Resolution Integral Nonlinearity Differential Nonlinearity Gain Error Power Supply Rejection Ratio Output Leakage Current (IOUT) N INL DNL GFSE PSRR ILKG REFERENCE INPUT Input Resistance RIN 7/15 kΩ min/max DIGITAL INPUTS Digital Input HIGH Digital Input LOW Input Leakage Current VIH VIL IIL VIN = 0V to VDD 2.4 0.8 ±1 V min V max µA max POWER SUPPLY Supply Current IDD Digital Inputs = VIH or VIL Digital Inputs = 0V to VDD 500 100 µA max µA max NOTE: Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed for standard product dice. Consult factory to negotiate specifications based on dice lot qualifications through sample lot assembly and testing. ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION VDD to GND .................................................................................. 0V, +7V VREF to GND ...................................................................................... ±25V VRFB to GND ...................................................................................... ±25V Digital Input Voltage Range ................................................. –0.3V to VDD Output Voltage (Pin 3) ......................................................... –0.3 V to VDD Operating Temperature Range AD ........................................................................................ 0°C to +70°C U, UC ............................................................................... –40°C to +85°C Junction Temperature .................................................................... +150°C Storage Temperature .................................................... –65°C to + 150°C Lead Temperature (soldering, 10s) .............................................. +300° C θJA .......................................................................................................................... +100°C/W θJC ........................................................................................... +42°C/W Top View CAUTION: 1. Do not apply voltages higher than VDD or less than GND potential on any terminal except VREF (Pin 1) and RFB (Pin 2). 2. The digital control inputs are ESD protected: however, permanent damage may occur on unprotected units from high-energy electrostatic fields. Keep units in conductive foam at all times until ready to use. 3. Use proper anti-static handling procedures. 4. Absolute Maximum Ratings apply to both packaged devices. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. PRODUCT DAC8043U DAC8043UC INL PACKAGE PACKAGE DRAWING NUMBER (1) 1LSB 1/2LSB –40°C to +85°C –40°C to +85°C 8-pin SOIC 8-pin SOIC 182 182 VREF 1 8 VDD RFB 2 7 CLK IOUT 3 6 SRI GND 4 5 LD ELECTROSTATIC DISCHARGE SENSITIVITY Any integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. PACKAGE/ORDERING INFORMATION TEMPERATURE RANGE 8-Pin SOIC 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 published specifications. NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. Digital Inputs: All digital inputs of the DAC8043 incorporate on-chip ESD protection circuitry. This protection is designed and has been tested to withstand five 2500V positive and negative discharges (100pF in series with 1500Ω) applied to each digital input. Analog Pins: Each analog pin has been tested to BurrBrown’s analog ESD test consisting of five 1000V positive and negative discharges (100pF in series with 1500Ω) applied to each pin. VREF and RFB show some sensitivity. 3 DAC8043 ® WRITE CYCLE TIMING DIAGRAM Bit 1 MSB(1) SRI Bit 11 2 11 1 tCH tCL Load Serial Data Into Input Register tASB tLD LD Load Input Register's Data Into DAC Register NOTE: (1) Data loaded MSB first. ® DAC8043 Bit 12 LSB tDH tDS CLK INPUT Bit 2 4 TYPICAL PERFORMANCE CURVES At VDD = +5V; VREF = +10V; IOUT = GND = 0V; TA = Full Temperature Range specified under Absolute Maximum Ratings, unless otherwise noted. LINEARITY ERROR vs REFERENCE VOLTAGE GAIN vs FREQUENCY 0 0.5 Digital Input = 1111 1111 1111 –20 0.25 Gain (dB) INL (LSB) –40 0 Digital Input = 0000 0000 0000 –60 –80 –0.25 VDD = +5V VREF = 100mV TA = +25°C –100 –0.5 –120 2 4 6 8 1k 10 100k 1M Frequency (Hz) SUPPLY CURRENT vs LOGIC INPUT VOLTAGE TOTAL HARMONIC DISTORTION vs FREQUENCY (Multiplying Mode) 10M 0 1.6 VDD = +5V VDD = +5V 1.4 VIN = 6Vrms –20 TA = +25°C 1.2 –40 1.0 THD (dB) IDD (mA) 10k VREF (V) 0.8 0.6 –60 –80 0.4 –100 0.2 0 –120 0 1 2 3 10 4 100 10000 DNL ERROR vs REFERENCE VOLTAGE LINEARITY ERROR vs DIGITAL CODE 1 0.5 TA = +25°C 0.75 VREF = +10V 0.25 0.5 DNL (LSB) Linearity Error (LSB) 1000 Frequency (Hz) VIN (V) 0.25 0 –0.25 0 –0.25 –0.5 –0.75 –0.5 –1 0 1024 2048 3072 2 4096 Digital Input Code (Decimal) 4 6 8 10 VREF (V) ® 5 DAC8043 DISCUSSION OF SPECIFICATIONS tains a constant current in each leg of the ladder regardless of the input code. The input resistance at VREF is therefore constant and can be driven by either a voltage or current, AC or DC, positive or negative polarity, and have a voltage range up to ±20V. RELATIVE ACCURACY This term, also known as end point linearity or integral linearity, describes the transfer function of analog output to digital input code. Relative accuracy describes the deviation from a straight line, after zero and full scale errors have been adjusted to zero. A CMOS switch transistor, included in series with the ladder terminating resistor and in series with the feedback resistor, RFB, compensates for the temperature drift of the ON resistance of the ladder switches. Figure 2 shows an equivalent circuit for the DAC. COUT is the output capacitance due to the N-channel switches and varies from about 80pF to 110pF with digital input code. The current source ILKG is the combination of surface and junction leakages to the substrate. ILKG approximately doubles every 10°C. RO is the equivalent output resistance of the D/A and it varies with input code. DIFFERENTIAL NONLINEARITY Differential nonlinearity is the deviation from an ideal 1LSB change in the output when the input code changes by 1LSB. A differential nonlinearity specification of 1LSB maximum guarantees monotonicity. GAIN ERROR Gain error is the difference between the full-scale DAC output and the ideal value. The ideal full scale output value for the DAC8043 is –(4095/4096)VREF . Gain error may be adjusted to zero using external trims as shown in Figure 4. R R OUTPUT LEAKAGE CURRENT The current which appears at IOUT with the DAC loaded with all zeros. All digital inputs of the DAC8043 incorporate on-chip ESD protection circuitry. This protection is designed to withstand 2.5kV (using the Human Body Model, 100pF and 1500Ω). However, industry standard ESD protection methods should be used when handling or storing these components. When not in use, devices should be stored in conductive foam or rails. The foam or rails should be discharged to the destination socket potential before devices are removed. POWER SUPPLY CONNECTIONS The DAC8043 is designed to operate on VDD = +5V ±5%. For optimum performance and noise rejection, power supply decoupling capacitors CD should be added as shown in the application circuits. These capacitors (1µF tantalum recommended) should be located close to the D/A. Output op amp analog common (+ input) should be connected as near to the GND pins of the DAC8043 as possible. CIRCUIT DESCRIPTION Figure 1 shows a simplified schematic of a DAC8043. The current from the VREF pin is switched between IOUT and GND by 12 single-pole double-throw CMOS switches. This mainR 2R 2R 2R 2R WIRING PRECAUTIONS To minimize AC feedthrough when designing a PC board, care should be taken to minimize capacitive coupling between the VREF lines and the IOUT lines. Coupling from any of the digital control or data lines might degrade the glitch performance. Solder the DAC8043 directly into the PC board without a socket. Sockets add parasitic capacitance (which can degrade AC performance). R RFB IOUT GND Bit 1 (MSB) Bit 2 Bit 3 Bit 12 (LSB) FIGURE 1. Simplified Circuit Diagram for the DAC. ® DAC8043 COUT ESD PROTECTION DIGITAL-TO-ANALOG GLITCH ENERGY The integrated area of the glitch pulse measured in nanovoltseconds. The key contributor to digital-to-analog glitch is charge injected by digital logic switching transients. 2R IOUT INSTALLATION OUTPUT CURRENT SETTLING TIME The time required for the output current to settle to within +0.01% of final value for a full scale step. R RO ILKG FIGURE 2. Equivalent Circuit for the DAC. FEEDTHROUGH ERROR The AC output error due to capacitive coupling from VREF to IOUT with the DAC loaded with all zeros. R DIN VREF x 4096 R GND OUTPUT CAPACITANCE The parasitic capacitance measured from IOUT to GND. VREF RFB VREF 6 AMPLIFIER OFFSET VOLTAGE The output amplifier used with the DAC8043 should have low input offset voltage to preserve the transfer function linearity. The voltage output of the amplifier has an error component which is the offset voltage of the op amp multiplied by the “noise gain” of the circuit. This “noise gain” is equal to (RF / RO + 1) where RO is the output impedance of the D/A IOUT terminal and RF is the feedback network impedance. The nonlinearity occurs due to the output impedance varying with code. If the 0 code case is excluded (where RO = infinity), the RO will vary from R to 3R providing a “noise gain” variation between 4/3 and 2. In addition, the variation of RO is nonlinear with code, and the largest steps in RO occur at major code transitions where the worst differential nonlinearity is also likely to be experienced. The nonlinearity seen at the amplifier output is 2VOS – 4VOS /3 = 2VOS/3. versus digital input code are listed in Table I. The operational amplifiers used in this circuit can be single amplifiers such as the OPA602, or a dual amplifier such as the OPA2107. C1 provides phase compensation to minimize settling time and overshoot when using a high speed operational amplifier. If an application requires the D/A to have zero gain error, the circuit shown in Figure 4 may be used. Resistor R2 induces a positive gain error greater than worst-case initial negative gain error. Trim resistor R1 provides a variable negative gain error and have sufficient trim range to correct for the worstcase initial positive gain error plus the error produced by R2. BIPOLAR CONFIGURATION Figure 5 shows the DAC8043 in a typical bipolar (fourquadrant) multiplying configuration. The analog output values versus digital input code are listed in Table II. The operational amplifiers used in this circuit can be single amplifiers such as the OPA602 or a dual amplifier such as the OPA2107. C1 provides phase compensation to minimize settling time and overshoot when using a high speed operational amplifier. The bipolar offset resistors R1–R2 should be ratio-matched to 0.01% to ensure the specified gain error performance. Thus, to maintain good nonlinearity the op amp offset should be much less than 1/2LSB. UNIPOLAR CONFIGURATION Figure 3 shows DAC8043 in a typical unipolar (two-quadrant) multiplying configuration. The analog output values DATA INPUT DATA INPUT ANALOG OUTPUT MSB ↓ ↓ LSB 1111 1111 1111 1000 0000 0000 0000 0000 0001 0000 0000 0000 –VREF (4095/4096) –VREF (2048/4096) = –1/2VREF –VREF (1/4096) 0 Volts TABLE I. Unipolar Output Code. VDD +5V + IOUT GND C1 10pF VIN R1 100Ω + CD 1µF RFB DAC +VREF (2047/2048) +VREF (1/2048) 0 Volts –VREF (1/2048) –VREF (2048/2048) TABLE II. Bipolar Output Code. VDD VREF +5V CD 1µF ANALOG OUTPUT MSB ↓ ↓ LSB 1111 1111 1111 1000 0000 0001 1000 0000 0000 0111 1111 1111 0000 0000 0000 V REF RFB – A1 + IOUT DAC VOUT R2 C1 10pF 47Ω – A1 + GND VOUT DAC8043 DAC8043 A1 OPA602 or 1/2 OPA2107. A1 OPA602 or 1/2 OPA2107. FIGURE 3. Unipolar Configuration. FIGURE 4. Unipolar Configuration with Gain Trim. R1 20k Ω +5V VDD VREF R2 20k Ω – CD + 1µF A2 R3 10k Ω VOUT + RFB C1 10pF IOUT DAC – A1 GND + A1–A2, OPA602 or 1/2 OPA2107. DAC8043 FIGURE 5. Bipolar Configuration. ® 7 DAC8043