HI5731 TM Data Sheet 12-Bit, 100 MSPS, High Speed D/A Converter May 2000 File Number 4070.6 Features • Throughput Rate . . . . . . . . . . . . . . . . . . . . . . . 100 MSPS The HI5731 is a 12-bit, 100 MSPS, D/A converter which is implemented in the Intersil BiCMOS 10V (HBC-10) process. Operating from +5V and -5.2V, the converter provides -20.48mA of full scale output current and includes an input data register and bandgap voltage reference. Low glitch energy and excellent frequency domain performance are achieved using a segmented architecture. The digital inputs are TTL/CMOS compatible and translated internally to ECL. All internal logic is implemented in ECL to achieve high switching speed with low noise. The addition of laser trimming assures 12-bit linearity is maintained along the entire transfer curve. • Low Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .650mW • Integral Linearity Error . . . . . . . . . . . . . . . . . . . . 0.75 LSB • Low Glitch Energy . . . . . . . . . . . . . . . . . . . . . . . . .3.0pV-s • TTL/CMOS Compatible Inputs • Improved Hold Time . . . . . . . . . . . . . . . . . . . . . . . . 0.25ns • Excellent Spurious Free Dynamic Range Applications • Cellular Base Stations • GSM Base Stations Ordering Information • Wireless Communications PART NUMBER TEMP. RANGE (oC) PACKAGE PKG. NO. • Direct Digital Frequency Synthesis HI5731BIP -40 to 85 28 Ld PDIP E28.6 • Signal Reconstruction HI5731BIB -40 to 85 28 Ld SOIC M28.3 • Test Equipment HI5731-EVS 25 Evaluation Board (SOIC) • High Resolution Imaging Systems • Arbitrary Waveform Generators Pinout HI5731 (PDIP, SOIC) TOP VIEW D11 (MSB) 1 28 DGND D10 2 27 AGND D9 3 26 REF OUT D8 4 25 CTRL OUT D7 5 24 CTRL IN D6 6 23 RSET D5 7 22 AVEE D4 8 21 IOUT D3 9 20 IOUT D2 10 19 ARTN D1 11 18 DVEE D0 (LSB) 12 17 DGND NC 13 16 DVCC NC 14 15 CLOCK 3-1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Corporation. | Copyright © Intersil Corporation 2000 HI5731 Typical Application Circuit +5V HI5731 0.01µF DVCC (16) D11 D11 (MSB) (1) D10 D10 (2) D9 D9 (3) D8 D8 (4) D7 D7 (5) D6 D6 (6) D5 D5 (7) D4 D4 (8) D3 D3 (9) D2 D2 (10) D1 D1 (11) D0 D0 (LSB) (12) 0.1µF (24) CTRL IN (25) CTRL OUT -5.2V (AVEE) (26) REF OUT D/A OUT (21) IOUT 64Ω 64Ω (20) IOUT (23) RSET 976Ω (19) ARTN CLK (15) (27) AGND 50Ω DGND (17, 28) (22) AVEE DVEE (18) 0.01µF 0.01µF 0.1µF 0.1µF - 5.2V (AVEE) - 5.2V (DVEE) Functional Block Diagram (LSB) D0 D1 D2 D3 8 LSBs CURRENT CELLS D4 12-BIT MASTER REGISTER D5 D6 DATA BUFFER/ LEVEL SHIFTER R2R NETWORK ARTN SLAVE REGISTER 227Ω D7 227Ω D8 15 D9 15 UPPER 4-BIT DECODER D10 15 SWITCHED CURRENT CELLS IOUT (MSB) D11 IOUT REF CELL CTRL IN CLK + OVERDRIVEABLE VOLTAGE REFERENCE AVEE AGND DVEE 3-2 DGND DVCC - REF OUT RSET 25Ω CTRL OUT HI5731 Absolute Maximum Ratings Thermal Information Digital Supply Voltage VCC to DGND . . . . . . . . . . . . . . . . . . . +5.5V Negative Digital Supply Voltage DVEE to DGND . . . . . . . . . . -5.5V Negative Analog Supply Voltage AVEE to AGND, ARTN . . . . . -5.5V Digital Input Voltages (D11-D0, CLK) to DGND. . . . . DVCC to -0.5V Internal Reference Output Current. . . . . . . . . . . . . . . . . . . . ±2.5mA Voltage from CTRL IN to AVEE . . . . . . . . . . . . . . . . . . . . 2.5V to 0V Control Amplifier Output Current . . . . . . . . . . . . . . . . . . . . . ±2.5mA Reference Input Voltage Range . . . . . . . . . . . . . . . . . .-3.7V to AVEE Analog Output Current (IOUT) . . . . . . . . . . . . . . . . . . . . . . . . . 30mA Thermal Resistance (Typical, Note 1) θJA (oC/W) PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Maximum Junction Temperature HI5731BIx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC (SOIC - Lead Tips Only) Operating Conditions Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications AVEE , DVEE = -4.94 to -5.46V, VCC = +4.75 to +5.25V, VREF = Internal TA = 25oC for All Typical Values HI5731BI TA = -40oC TO 85oC PARAMETER TEST CONDITIONS MIN TYP MAX UNITS SYSTEM PERFORMANCE Resolution Integral Linearity Error, INL (Note 4) (“Best Fit” Straight Line) 12 - - Bits - 0.75 1.5 LSB Differential Linearity Error, DNL (Note 4) - 0.5 1.0 LSB Offset Error, IOS (Note 4) - 20 75 µA Full Scale Gain Error, FSE (Notes 2, 4) - 1 10 % Offset Drift Coefficient (Note 3) - - 0.05 µA/oC - 20.48 - mA (Note 3) -1.25 - 0 V Throughput Rate (Note 3) 100 - - MSPS Output Voltage Full Scale Step Settling Time, tSETT , Full Scale To ±0.5 LSB Error Band RL = 50Ω (Note 3) - 20 - ns Singlet Glitch Area, GE (Peak) RL = 50Ω (Note 3) - 5 - pV-s - 3 - pV-s Output Slew Rate RL = 50Ω, DAC Operating in Latched Mode (Note 3) - 1,000 - V/µs Output Rise Time RL = 50Ω, DAC Operating in Latched Mode (Note 3) - 675 - ps Output Fall Time RL = 50Ω, DAC Operating in Latched Mode (Note 3) - 470 - ps Spurious Free Dynamic Range within a Window (Note 3) fCLK = 10 MSPS, fOUT = 1.23MHz, 2MHz Span - 85 - dBc Full Scale Output Current, IFS Output Voltage Compliance Range DYNAMIC CHARACTERISTICS Doublet Glitch Area, (Net) Spurious Free Dynamic Range to Nyquist (Note 3) fCLK = 20 MSPS, fOUT = 5.055MHz, 2MHz Span - 77 - dBc fCLK = 40 MSPS, fOUT = 16MHz, 10MHz Span - 75 - dBc fCLK = 50 MSPS, fOUT = 10.1MHz, 2MHz Span - 80 - dBc dBc fCLK = 80 MSPS, fOUT = 5.1MHz, 2MHz Span - 78 - fCLK = 100 MSPS, fOUT = 10.1MHz, 2MHz Span - 79 - dBc fCLK = 40 MSPS, fOUT = 2.02MHz, 20MHz Span - 70 - dBc fCLK = 80 MSPS, fOUT = 2.02MHz, 40MHz Span - 70 - dBc fCLK = 100 MSPS, fOUT = 2.02MHz, 50MHz Span - 69 - dBc REFERENCE/CONTROL AMPLIFIER Internal Reference Voltage, VREF (Note 4) -1.27 -1.23 -1.17 V Internal Reference Voltage Drift (Note 3) - 175 - µV/oC Internal Reference Output Current Sink/Source Capability (Note 3) -125 - +50 µA 3-3 HI5731 Electrical Specifications AVEE , DVEE = -4.94 to -5.46V, VCC = +4.75 to +5.25V, VREF = Internal TA = 25oC for All Typical Values (Continued) HI5731BI TA = -40oC TO 85oC MIN TYP MAX Internal Reference Load Regulation IREF = 0 to IREF = -125µA - 50 - µV Input Impedance at REF OUT pin (Note 3) - 1.4 - kΩ Amplifier Large Signal Bandwidth (0.6VP-P) Sine Wave Input, to Slew Rate Limited (Note 3) - 3 - MHz Amplifier Small Signal Bandwidth (0.1VP-P) Sine Wave Input, to -3dB Loss (Note 3) - 10 - MHz Reference Input Impedance (Note 3) - 12 - kΩ Reference Input Multiplying Bandwidth (CTL IN) RL = 50Ω, 100mV Sine Wave, to -3dB Loss at IOUT (Note 3) - 200 - MHz PARAMETER TEST CONDITIONS UNITS DIGITAL INPUTS (D9-D0, CLK, INVERT) Input Logic High Voltage, VIH (Note 4) 2.0 - - V Input Logic Low Voltage, VIL (Note 4) - - 0.8 V Input Logic Current, IIH (Note 4) - - 400 µA Input Logic Current, IIL (Note 4) - - 700 µA Digital Input Capacitance, CIN (Note 3) - 3.0 - pF TIMING CHARACTERISTICS Data Setup Time, tSU See Figure 1 (Note 3) 3.0 2.0 - ns Data Hold Time, tHLD See Figure 1 (Note 3) 0.5 0.25 - ns Propagation Delay Time, tPD See Figure 1 (Note 3) - 4.5 - ns CLK Pulse Width, tPW1, tPW2 See Figure 1 (Note 3) 3.0 - - ns POWER SUPPLY CHARACTERISTICS IEEA (Note 4) - 42 50 mA IEED (Note 4) - 70 85 mA ICCD (Note 4) - 13 20 mA Power Dissipation (Note 4) - 650 - mW Power Supply Rejection Ratio VCC ±5%, VEE ±5% - 5 - µA/V NOTES: 2. Gain Error measured as the error in the ratio between the full scale output current and the current through RSET (typically 1.28mA). Ideally the ratio should be 16. 3. Parameter guaranteed by design or characterization and not production tested. 4. All devices are 100% tested at 25oC. 100% production tested at temperature extremes for military temperature devices, sample tested for industrial temperature devices. 5. Dynamic Range must be limited to a 1V swing within the compliance range. Timing Diagrams 50% CLK GLITCH AREA = 1/2 (H x W) V D11-D0 HEIGHT (H) ±1/2 LSB ERROR BAND IOUT WIDTH (W) t(ps) tSETT tPD FIGURE 1. FULL SCALE SETTLING TIME DIAGRAM 3-4 FIGURE 2. PEAK GLITCH AREA (SINGLET) MEASUREMENT METHOD HI5731 Timing Diagrams (Continued) tPW2 tPW1 50% CLK tSU tSU tHLD tSU tHLD tHLD D11-D0 tPD IOUT tPD tPD FIGURE 3. PROPAGATION DELAY, SETUP TIME, HOLD TIME AND MINIMUM PULSE WIDTH DIAGRAM Typical Performance Curves -1.21 680 CLOCK FREQUENCY DOES NOT ALTER POWER DISSIPATION -1.23 (V) (mW) 640 600 -1.27 -1.29 560 -50 -1.25 -30 -10 10 30 50 70 TEMPERATURE FIGURE 4. TYPICAL POWER DISSIPATION OVER TEMPERATURE 3-5 90 -50 -30 -10 10 30 50 70 TEMPERATURE FIGURE 5. TYPICAL REFERENCE VOLTAGE OVER TEMPERATURE 90 HI5731 Typical Performance Curves (Continued) 1.5 0.8 0.5 (LSB) (LSB) 0.4 0.0 -0.5 -0.4 -0.8 1.5 0 600 1200 1800 2400 3000 3600 400 4200 1000 1600 2200 2800 3400 4000 CODE CODE FIGURE 6. TYPICAL INL FIGURE 7. TYPICAL DNL ATTEN 20dB RL -10.0dBm 10dB/ 28 ∆MKR -87.33dB -73kHz fC = 10 MSPS (µA) 24 S 20 16 C 12 -40 -20 -0 20 40 60 80 CENTER 1.237MHz 100 SPAN 2.000MHz TEMPERATURE FIGURE 8. OFFSET CURRENT OVER TEMPERATURE ATTEN 20dB RL -10.0dBm 10dB/ FIGURE 9. SPURIOUS FREE DYNAMIC RANGE = 87.3dBc ∆MKR -76.16dB -53kHz ATTEN 20dB RL -10.0dBm fC = 20 MSPS 10dB/ ∆MKR -75.17dB -70kHz fC = 40 MSPS S C C CENTER 5.055MHz SPAN 2.000MHz FIGURE 10. SPURIOUS FREE DYNAMIC RANGE = 76.16dBc 3-6 CENTER 16.00MHz SPAN 10.00MHz FIGURE 11. SPURIOUS FREE DYNAMIC RANGE = 75.17dBc HI5731 Typical Performance Curves ATTEN 20dB RL -10.0dBm 10dB/ (Continued) ∆MKR -81.67dB -953kHz ATTEN 20dB RL -10.0dBm 10dB/ fC = 50 MSPS ∆MKR -77.00dB -93kHz fC = 80 MSPS S C C CENTER 10.100MHz SPAN 2.000MHz FIGURE 12. SPURIOUS FREE DYNAMIC RANGE = -81.67dBc ATTEN 20dB RL -10.0dBm 10dB/ CENTER 5.097MHz SPAN 2.000MHz FIGURE 13. SPURIOUS FREE DYNAMIC RANGE = 77dBc ∆MKR -85.60dB -33kHz ATTEN 20dB RL -10.0dBm 10dB/ fC = 100 MSPS fC = 100 MSPS S S C C CENTER 2.027MHz SPAN 2.000MHz FIGURE 14. SPURIOUS FREE DYNAMIC RANGE = -85.60dBc ATTEN 20dB RL -10.0dBm 10dB/ ∆MKR -85.50dB 73kHz CENTER 5.000MHz SPAN 2.000MHz FIGURE 15. SPURIOUS FREE DYNAMIC RANGE = 85.5dBc ∆MKR -80.50dB -807kHz ATTEN 20dB RL -10.0dBm fC = 100 MSPS 10dB/ ∆MKR -72.17dB -467kHz fC = 100 MSPS S C CENTER 10.133MHz SPAN 2.000MHz FIGURE 16. SPURIOUS FREE DYNAMIC RANGE = 80.5dBc 3-7 CENTER 26.637MHz SPAN 2.000MHz FIGURE 17. SPURIOUS FREE DYNAMIC RANGE = 72.17dBc HI5731 Typical Performance Curves ATTEN 20dB RL -10.0dBm (Continued) ∆MKR -71.16dB 2.99MHz 10dB/ ATTEN 20dB RL -10.0dBm ∆MKR -70.50dB 1.98MHz 10dB/ fC = 40 MSPS fO = 2.02MHz fC = 80 MSPS fO = 2.02MHz S S C C START FREQUENCY 500kHz START FREQUENCY 500kHz STOP FREQUENCY 20MHz FIGURE 18. SPURIOUS FREE DYNAMIC RANGE = 71.16dBc ATTEN 20dB RL -10.0dBm STOP FREQUENCY 40MHz FIGURE 19. SPURIOUS FREE DYNAMIC RANGE = 70.5dBc 10dB/ ∆MKR -70.00dB 4.13MHz fC = 100 MSPS fO = 2.02MHz S C START FREQUENCY 500kHz STOP FREQUENCY 50MHz FIGURE 20. SPURIOUS FREE DYNAMIC RANGE = 70dBc Pin Descriptions PIN NUMBER 1-12 PIN NAME PIN DESCRIPTION D11 (MSB) thru Digital Data Bit 11, the Most Significant Bit thru Digital Data Bit 0, the Least Significant Bit. D0 (LSB) 15 CLK Data Clock Pin DC to 100 MSPS. 13, 14 NC No Connect. 16 DVCC Digital Logic Supply +5V. 17, 28 DGND Digital Ground. 18 DVEE -5.2V Logic supply. 23 RSET External resistor to set the full scale output current. IFS = 16 x (VREF OUT / RSET). Typically 976Ω. 27 AGND Analog Ground supply current return pin. 19 ARTN Analog Signal Return for the R/2R ladder. 21 IOUT Current Output Pin. 20 IOUT Complementary Current Output Pin. 22 AVEE -5.2V Analog Supply. 24 CTRL IN Input to the current source base rail. Typically connected to CTRL OUT and a 0.1µF capacitor to AVEE . Allows external control of the current sources. 25 CTRL OUT Control Amplifier Out. Provides precision control of the current sources when connected to CTRL IN such that IFS = 16 x (VREF OUT / RSET). 26 REF OUT 3-8 -1.23V (Typ) bandgap reference voltage output. Can sink up to 125µA or be overdriven by an external reference capable of delivering up to 2mA. HI5731 Detailed Description The HI5731 is a 12-bit, current out D/A converter. The DAC can convert at 100 MSPS and runs on +5V and -5.2V supplies. The architecture is an R/2R and segmented switching current cell arrangement to reduce glitch. Laser trimming is employed to tune linearity to true 12-bit levels. The HI5731 achieves its low power and high speed performance from an advanced BiCMOS process. The HI5731 consumes 650mW (typical) and has an improved hold time of only 0.25ns (typical). The HI5731 is an excellent converter for use in communications applications and high performance instrumentation systems. Digital Inputs The HI5731 is a TTL/CMOS compatible D/A. Data is latched by a Master register. Once latched, data inputs D0 (LSB) thru D11 (MSB) are internally translated from TTL to ECL. The internal latch and switching current source controls are implemented in ECL technology to maintain high switching speeds and low noise characteristics. Decoder/Driver The architecture employs a split R/2R ladder and Segmented Current source arrangement. Bits D0 (LSB) thru D7 directly drive a typical R/2R network to create the binary weighted current sources. Bits D8 thru D11 (MSB) pass thru a “thermometer” decoder that converts the incoming data into 15 individual segmented current source enables. This split architecture helps to improve glitch, thus resulting in a more constant glitch characteristic across the entire output transfer function. Clocks and Termination The internal 12-bit register is updated on the rising edge of the clock. Since the HI5731 clock rate can run to 100 MSPS, to minimize reflections and clock noise into the part proper termination should be used. In PCB layout clock runs should be kept short and have a minimum of loads. To guarantee consistent results from board to board controlled impedance PCBs should be used with a characteristic line impedance ZO of 50Ω. To terminate the clock line, a shunt terminator to ground is the most effective type at a 100 MSPS clock rate. A typical value for termination can be determined by the equation: ZO = 50Ω CLK HI5731 DAC RT = 50Ω FIGURE 21. CLOCK LINE TERMINATION Rise and Fall times and propagation delay of the line will be affected by the Shunt Terminator. The terminator should be connected to DGND. Noise Reduction To reduce power supply noise, separate analog and digital power supplies should be used with 0.1µF and 0.01µF ceramic capacitors placed as close to the body of the HI5731 as possible on the analog (AVEE ) and digital (DVEE ) supplies. The analog and digital ground returns should be connected together back at the device to ensure proper operation on power up. The VCC power pin should also be decoupled with a 0.1µF capacitor. Reference The internal reference of the HI5731 is a -1.23V (typical) bandgap voltage reference with 175µV/oC of temperature drift (typical). The internal reference is connected to the Control Amplifier which in turn drives the segmented current cells. Reference Out (REF OUT) is internally connected to the Control Amplifier. The Control Amplifier Output (CTRL OUT) should be used to drive the Control Amplifier Input (CTRL IN) and a 0.1µF capacitor to analog VEE. This improves settling time by providing an AC ground at the current source base node. The Full Scale Output Current is controlled by the REF OUT pin and the set resistor (RSET). The ratio is: IOUT (Full Scale) = (VREF OUT /RSET) x 16, The internal reference (REF OUT) can be overdriven with a more precise external reference to provide better performance over temperature. Figure 22 illustrates a typical external reference configuration. HI5731 RT = ZO , for the termination resistor. For a controlled impedance board with a ZO of 50Ω, the RT = 50Ω. Shunt termination is best used at the receiving end of the transmission line or as close to the HI5731 CLK pin as possible. (26) REF OUT -1.25V R -5.2V FIGURE 22. EXTERNAL REFERENCE CONFIGURATION 3-9 HI5731 Multiplying Capability The HI5731 can operate in two different multiplying configurations. For frequencies from DC to 100kHz, a signal of up to 0.6VP-P can be applied directly to the REF OUT pin as shown in Figure 23. TABLE 1. CAPACITOR SELECTION fIN C1 C2 100kHz 0.01µF 1µF >1MHz 0.001µF 0.1µF HI5731 CTRL OUT CTRL IN 0.01µF AVEE REF OUT VIN CIN (OPTIONAL) RSET FIGURE 23. LOW FREQUENCY MULTIPLYING BANDWIDTH CIRCUIT The signal must have a DC value such that the peak negative voltage equals -1.25V. Alternately, a capacitor can be placed in series with REF OUT if DC multiplying is not required. The lower input bandwidth can be calculated using the following formula: 1 C IN = -------------------------------------------. ( 2 π ) ( 1400 ) ( f IN ) For multiplying frequencies above 100kHz, the CTRL IN pin can be driven directly as seen in Figure 24. HI5731 CTRL OUT C2 200Ω VIN AVEE C1 CTRL IN 50Ω Also, the input signal must be limited to 1VP-P to avoid distortion in the DAC output current caused by excessive modulation of the internal current sources. Outputs The outputs IOUT and IOUT are complementary current outputs. Current is steered to either IOUT or IOUT in proportion to the digital input code. The sum of the two currents is always equal to the full scale current minus one LSB. The current output can be converted to a voltage by using a load resistor. Both current outputs should have the same load resistor (64Ω typically). By using a 64Ω load on the output, a 50Ω effective output resistance (ROUT) is achieved due to the 227Ω (±15%) parallel resistance seen looking back into the output. This is the nominal value of the R2R ladder of the DAC. The 50Ω output is needed for matching the output with a 50Ω line. The load resistor should be chosen so that the effective output resistance (ROUT) matches the line resistance. The output voltage is: VOUT = IOUT x ROUT. IOUT is defined in the reference section. IOUT is not trimmed to 12 bits, so it is not recommended that it be used in conjunction with IOUT in a differential-to-single-ended application. The compliance range of the output is from 1.25V to 0V, with a 1VP-P voltage swing allowed within this range. TABLE 2. INPUT CODING vs CURRENT OUTPUT INPUT CODE (D11-D0) FIGURE 24. HIGH FREQUENCY MULTIPLYING BANDWIDTH CIRCUIT The nominal input/output relationship is defined as: ∆V IN ∆I OUT = -------------- . 80Ω IOUT (mA) IOUT (mA) 1111 1111 1111 -20.48 0 1000 0000 0000 -10.24 -10.24 0000 0000 0000 0 -20.48 Settling Time In order to prevent the full scale output current from exceeding 20.48mA, the RSET resistor must be adjusted according to the following equation: 16V REF R SET = -----------------------------------------------------------------------------------------------. V IN ( PEAK ) I OUT (FULL SCALE) – ----------------------------- 80Ω The circuit in Figure 24 can be tuned to adjust the lower cutoff frequency by adjusting capacitor values. Table 1 below illustrates the relationship. 3-10 The settling time of the HI5731 is measured as the time it takes for the output of the DAC to settle to within a 1/2 LSB error band of its final value during a full scale (code 0000... to 1111.... or 1111... to 0000...) transition. All claims made by Intersil with respect to the settling time performance of the HI5731 have been fully verified by the National Institute of Standards and Technology (NIST) and are fully traceable. Glitch The output glitch of the HI5731 is measured by summing the area under the switching transients after an update of the DAC. Glitch is caused by the time skew between bits of the incoming digital data. Typically, the switching time of digital inputs are asymmetrical meaning that the turn off time is HI5731 faster than the turn on time (TTL designs). Unequal delay paths through the device can also cause one current source to change before another. In order to minimize this, the Intersil HI5731 employes an internal register, just prior to the current sources, which is updated on the clock edge. Lastly, the worst case glitch on traditional D/A converters usually occurs at the major transition (i.e., code 2047 to 2048). However, due to the split architecture of the HI5731, the glitch is moved to the 255 to 256 transition (and every subsequent 256 code transitions thereafter). This split R/2R segmented current source architecture, which decreases the amount of current switching at any one time, makes the glitch practically constant over the entire output range. By making the glitch a constant size over the entire output range this effectively integrates this error out of the end application. buffered to create the bipolar offset current needed to generate the -2V output with all bits ‘off’. The output current must be converted to a voltage and then gained up and offset to produce the proper swing. Care must be taken to compensate for the voltage swing and error. 5kΩ REF OUT (26) HI5731 - + 5kΩ 1/ CA2904 2 1/ CA2904 2 0.1µF 60Ω 240Ω HI5731 240Ω 50Ω IOUT (21) In measuring the output glitch of the HI5731 the output is terminated into a 64Ω load. The glitch is measured at any one of the current cell carry (code 255 to 256 transition or any multiple thereof) throughout the DACs output range. The glitch energy is calculated by measuring the area under the voltage-time curve. Figure 26 shows the area considered as glitch when changing the DAC output. Units are typically specified in picoVolt-seconds (pV-s). - + - VOUT + HFA1100 FIGURE 27. BIPOLAR OUTPUT CONFIGURATION Interfacing to the HSP45106 NCO-16 The HSP45106 is a 16-bit, Numerically Controlled Oscillator (NCO). The HSP45106 can be used to generate various modulation schemes for Direct Digital Synthesis (DDS) applications. Figure 28 shows how to interface an HI5731 to the HSP45106. Interfacing to the HSP45102 NCO-12 100MHz LOW PASS FILTER (21) IOUT SCOPE 64Ω 50Ω FIGURE 25. GLITCH TEST CIRCUIT The HSP45102 is a 12-bit, Numerically Controlled Oscillator (NCO). The HSP45102 can be used to generate various modulation schemes for Direct Digital Synthesis (DDS) applications. Figure 29 shows how to interface an HI5731 to the HSP45102. This high level block diagram is that of a basic PSK modulator. In this example the encoder generates the PSK waveform by driving the Phase Modulation Inputs (P1, P0) of the HSP45102. The P1-0 inputs impart a phase shift to the carrier wave as defined in Table 2. TABLE 3. PHASE MODULATION INPUT CODING a (mV) GLITCH ENERGY = (a x t)/2 t (ns) FIGURE 26. MEASURING GLITCH ENERGY Applications Bipolar Applications To convert the output of the HI5731 to a bipolar 4V swing, the following applications circuit is recommended. The reference can only provide 125µA of drive, so it must be 3-11 P1 P0 PHASE SHIFT (DEGREES) 0 0 0 0 1 90 1 0 270 1 1 180 The data port of the HSP45102 drives the 12-bit HI5731 DAC which converts the NCO output into an analog waveform. The output filter connected to the DAC can be tailored to remove unwanted spurs for the desired carrier frequency. The controller is used to load the desired center frequency and control the HSP45102. The HI5731 coupled with the HSP45102 make an inexpensive PSK modulator with Spurious Free performance down to -76dBc. HI5731 Definition of Specifications Integral Linearity Error, INL, is the measure of the worst case point that deviates from a best fit straight line of data values along the transfer curve. Differential Linearity Error, DNL, is the measure of the error in step size between adjacent codes along the converter’s transfer curve. Ideally, the step size is 1 LSB from one code to the next, and the deviation from 1 LSB is known as DNL. A DNL specification of greater than -1 LSB guarantees monotonicity. Feedthru, is the measure of the undesirable switching noise coupled to the output. Output Voltage Full Scale Settling Time, is the time required from the 50% point on the clock input for a full scale step to settle within an ±1/2 LSB error band. Output Voltage Small Scale Settling Time, is the time required from the 50% point on the clock input for a 100mV step to settle within an 1/2 LSB error band. This is used by applications reconstructing highly correlated signals such as sine waves with more than 5 points per cycle. Glitch Area, GE, is the switching transient appearing on the output during a code transition. It is measured as the area under the curve and expressed as a picoVolt-time specification (typically pV-s). Differential Gain, ∆AV, is the gain error from an ideal sine wave with a normalized amplitude. Differential Phase, ∆Φ, is the phase error from an ideal sine wave. Signal to Noise Ratio, SNR, is the ratio of a fundamental to the noise floor of the analog output. The first 5 harmonics are ignored, and an output filter of 1/2 the clock frequency is used to eliminate alias products. Total Harmonic Distortion, THD, is the ratio of the DAC output fundamental to the RMS sum of the harmonics. The first 5 harmonics are included, and an output filter of 1/2 the clock frequency is used to eliminate alias products. Spurious Free Dynamic Range, SFDR, is the amplitude difference from a fundamental to the largest harmonically or non-harmonically related spur. A sine wave is loaded into the D/A and the output filtered at 1/2 the clock frequency to eliminate noise from clocking alias terms. Intermodulation Distortion, IMD, is the measure of the sum and difference products produced when a two tone input is driven into the D/A. The distortion products created will arise at sum and difference frequencies of the two tones. IMD can be calculated using the following equation: 20Log (RMS of Sum and Difference Distortion Products) IMD = ------------------------------------------------------------------------------------------------------------------------------------------------------- . ( RMS Amplitude of the Fundamental ) 3-12 HI5731 U2 33 MSPS CLK BASEBAND BIT STREAM K9 C11 B11 ENCODER C10 A11 F10 F9 F11 H11 G11 G9 J11 G10 D10 VCC CONTROLLER J10 K11 B8 A8 B6 B7 A7 C7 C6 A6 A5 C5 A4 B4 A3 A2 B3 A1 B10 B9 A10 E11 E9 VCC H10 K2 J2 V CC CLK MOD2 MOD1 U1 MOD0 PMSEL DACSTRB ENPOREG ENOFREG ENCFREG ENPHAC ENTIREG INHOFR INITPAC INITTAC TEST PARSER BINFMT C15_MSB C4 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 C0 A2 A1 A0 CS WR FILTER SIN15 SIN14 SIN13 SIN12 SIN11 SIN10 SIN9 SIN8 SIN7 SIN6 SIN5 SIN4 SIN3 SIN2 SIN1 SIN0 L1 K3 L2 L3 L4 J5 K5 L5 K6 J6 J7 L7 L6 L8 K8 L9 L10 VCC 16 1 2 3 4 5 6 7 8 9 10 11 12 15 R4 50 DVCC IOUT D11 (MSB) D10 IOUT D9 D8 D7 CNTRL IN D6 D5 D4 CNTRL OUT D3 D2 D1 D0 (LSB) REF OUT RSET ARET COS15 COS14 COS13 COS12 COS11 COS10 COS9 COS8 COS7 COS6 COS5 COS4 COS3 COS2 COS1 COS0 PACI TICO C2 B1 C1 D1 E3 E2 E1 F2 F3 G3 G1 G2 H1 H2 J1 K1 R1 21 64 R2 20 64 24 25 0.1µF C1 0.01µF R3 23 976 19 AVSS 27 18 -5.2V_D AVEE DVEE 22 -5.2V_A HI5731 L1 -5.2V_D -5.2V_A 10µH L2 10µH B2 OES OEC HSP45106 FIGURE 28. MODULATOR USING THE HI5731 AND THE HSP45106 16-BIT NCO 3-13 C2 26 CLK 28 DGND 17 DGND TO RF UP-CONVERT STAGE -5.2V_A -5.2V_A HI5731 FILTER U2 U1 BASEBAND BIT STREAM 40 MSPS I CLK ENCODER Q 16 19 20 18 17 12 9 CONTROL BUS VCC CLK P1 P0 LOAD# TXFR# ENPHAC# SEL_L/M# CONTROLLER 14 13 10 11 OUT11 OUT10 OUT9 OUT8 OUT7 OUT6 OUT5 OUT4 OUT3 OUT2 OUT1 OUT0 16 DVCC IOUT 1 2 3 4 5 6 7 8 9 10 11 12 6 5 4 3 2 1 28 27 26 25 24 23 D11 (MSB) D10 IOUT D9 D8 D7 CNTRL IN D6 D5 CNTRL OUT D4 D3 D2 D1 D0 (LSB) REF OUT 15 CLK SCLK R4 50 SD 28 DGND 17 DGND SFTEN# RSET R1 21 64 R2 20 64 24 25 C2 0.1µF C1 0.01µF 26 R3 23 976 ARET 19 AVSS 27 MSB/LSB# HSP45102 18 -5.2V_D AVEE DVEE 22 -5.2V_A HI5731 L1 -5.2V_D 10µH L2 -5.2V_A 10µH FIGURE 29. PSK MODULATOR USING THE HI5731 AND THE HSP45102 12-BIT NCO 3-14 TO RF UP-CONVERT STAGE -5.2V_A -5.2V_A HI5731 Die Characteristics DIE DIMENSIONS: PASSIVATION: 161.5 mils x 160.7 mils x 19 mils Type: Sandwich Passivation Undoped Silicon Glass (USG) + Nitride Thickness: USG - 8kÅ, Nitride - 4.2kÅ Total 12.2kÅ + 2kÅ METALLIZATION: Type: AlSiCu Thickness: M1 - 8kÅ, M2 - 17kÅ SUBSTRATE POTENTIAL (POWERED UP): VEED Metallization Mask Layout D9 D10 D11 DGND REF OUT D8 AGND HI5731 CTRL OUT D7 CTRL IN D6 RSET D5 AVEE D4 IOUT D3 IOUT D2 ARTN D1 D0 CLK DVCC DGND DVEE All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. 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