HI5741 TM Data Sheet May 2000 14-Bit, 100 MSPS, High Speed D/A Converter File Number 4071.7 Features • Throughput Rate . . . . . . . . . . . . . . . . . . . . . . . 100 MSPS The HI5741 is a 14-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 14-bit linearity is maintained along the entire transfer curve. • Low Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .650mW • Integral Linearity Error . . . . . . . . . . . . . . . . . . . . . . . 1 LSB • Low Glitch Energy . . . . . . . . . . . . . . . . . . . . . . . . . . 1pV-s • TTL/CMOS Compatible Inputs • Improved Hold Time . . . . . . . . . . . . . . . . . . . . . . . . 0.25ns • Excellent Spurious Free Dynamic Range Applications • Cellular Base Stations • Wireless Communications Ordering Information • Direct Digital Frequency Synthesis PART NUMBER TEMP. RANGE (oC) PACKAGE PKG. NO. • Signal Reconstruction HI5741BIP -40 to 85 28 Ld PDIP E28.6 • Test Equipment HI5741BIB -40 to 85 28 Ld SOIC M28.3 • High Resolution Imaging Systems HI5741-EVS 25 Evaluation Board (SOIC) • Arbitrary Waveform Generators Pinout HI5741 (PDIP, SOIC) TOP VIEW D13 (MSB) 1 28 DGND D12 2 27 AGND D11 3 26 REF OUT D10 4 25 CTRL AMP OUT D9 5 24 CTRL AMP IN D8 6 23 RSET D7 7 22 AVEE D6 8 21 IOUT D5 9 20 IOUT D4 10 19 ARTN D3 11 18 DVEE D2 12 17 DGND D1 13 16 DVCC D0 (LSB) 14 3-1 15 CLOCK 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 HI5741 Typical Application Circuit +5V HI5741 0.01µF DVCC (16) D13 D13 (MSB) (1) D12 D12 (2) D11 D11 (3) D10 D10 (4) D9 D9 (5) D8 D8 (6) D7 D7 (7) D6 D6 (8) D5 D5 (9) D4 D4 (10) D3 D3 (11) (20) IOUT D2 D2 (12) D1 D1 (13) (23) RSET D0 D0 (LSB) (14) CLK (15) 50Ω (25) CTRL AMP OUT -5.2V (AVEE) (26) REF OUT D/A OUT (21) IOUT 64Ω 64Ω 976Ω (19) ARTN (27) AGND DGND (17, 28) (22) AVEE DVEE (18) 0.1µF 0.1µF (24) CTRL AMP IN 0.01µF 0.01µF 0.1µF -5.2V (AVEE) -5.2V (DVEE) Functional Block Diagram (LSB) D0 D1 D2 D3 D4 10 LSBs CURRENT CELLS D5 14-BIT MASTER REGISTER D6 D7 DATA BUFFER/ LEVEL SHIFTER R2R NETWORK ARTN SLAVE REGISTER 227Ω D8 227Ω D9 D10 15 D11 15 UPPER 4-BIT DECODER D12 15 SWITCHED CURRENT CELLS IOUT IOUT (MSB) D13 REF CELL CLK + OVERDRIVEABLE VOLTAGE REFERENCE AVEE AGND DVEE 3-2 DGND DVCC - REF OUT RSET 25Ω CTRL AMP IN CTRL AMP OUT HI5741 Absolute Maximum ratings TA = 25oC Thermal Information Thermal Resistance (Typical, Note 1) θJA (oC/W) PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Maximum Junction Temperature HI5741BIx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC (SOIC - Lead Tips Only) 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 (D13-D0, CLK) to DGND. . . . . DVCC to -0.5V Internal Reference Output Current. . . . . . . . . . . . . . . . . . . . ±2.5mA Voltage from CTRL AMP 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 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 HI5741BI TA = -40oC TO 85oC PARAMETER TEST CONDITIONS MIN TYP MAX UNITS - Bits SYSTEM PERFORMANCE Resolution 14 - - 1.0 1.5 LSB - - 1.75 LSB Differential Linearity Error, DNL “Best Fit Straight Line”, TA = 25oC “Best Fit Straight Line”, TA = -40oC to 85oC (Note 5) TA = 25oC - 0.5 1.0 LSB Offset Error, IOS (Note 5) - 8 75 µA Integral Linearity Error, INL (Notes 5) Full Scale Gain Error, FSE (Notes 3, 5) - 3.2 10 % Offset Drift Coefficient (Note 4) - - 0.05 µA/oC - -20.48 - mA (Note 4) -1.25 - 0 V Throughput Rate (Note 4) 100 - - MSPS Output Voltage Settling Time (1/16th Scale Step Across Segment) RL = 64Ω (Note 4) - Settling to 0.024% - 11 - ns RL = 64Ω (Note 4) - Settling to 0.012% - 20 - ns Singlet Glitch Area, GE (Peak) RL = 64Ω (Note 4) - 1 - pV•s Output Slew Rate RL = 64Ω, DAC Operating in Latched Mode (Note 4) - 1,000 - V/µs Output Rise Time RL = 64Ω, DAC Operating in Latched Mode (Note 4) - 675 - ps Output Fall Time RL = 64Ω, DAC Operating in Latched Mode (Note 4) - 470 - ps Spurious Free Dynamic Range within a Window (Note 4) fCLK = 10 MSPS, fOUT = 1.23MHz, 2MHz Span - 87 - dBc 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 Full Scale Output Current, IFS Output Voltage Compliance Range DYNAMIC CHARACTERISTICS Spurious Free Dynamic Range to Nyquist (Notes 4) 3-3 fCLK = 80 MSPS, fOUT = 5.1MHz, 2MHz Span - 78 - dBc fCLK = 100 MSPS, fOUT = 10.1MHz, 2MHz Span - 79 - dBc fCLK = 10 MSPS, fOUT = 1.023MHz, 5MHz Span - 86 - dBc fCLK = 10 MSPS, fOUT = 2.02MHz, 5MHz Span - 85 - dBc fCLK = 25 MSPS, fOUT = 2.02MHz, 12.5MHz Span - 77 - dBc fCLK = 50 MSPS, fOUT = 5.055MHz, 25MHz Span - 74 - dBc fCLK = 75 MSPS, fOUT = 7.52MHz, 37.5MHz Span - 73 - dBc fCLK = 100 MSPS, fOUT = 10.1MHz, 50MHz Span - 71 - dBc HI5741 Electrical Specifications AVEE , DVEE = -4.94 to -5.46V, VCC = +4.75 to +5.25V, VREF = Internal, TA = 25oC (Continued) HI5741BI TA = -40oC TO 85oC PARAMETER Multi-Tone Power Ratio (MTPR) TEST CONDITIONS 8 Tones, no Clipping, 110kHz Spacing, 220kHz spacing between tones 4 and 5, fCLK = 20 MSPS (Note 7) MIN TYP MAX UNITS - 76 - dBc REFERENCE/CONTROL AMPLIFIER Internal Reference Voltage, VREF (Notes 5) -1.27 -1.23 -1.17 V Internal Reference Voltage Drift (Note 4) - 50 - µV/oC Internal Reference Output Current Sink/Source Capability (Note 4) -500 - +50 µA Internal Reference Load Regulation IREF = 0 to IREF = -500µA - 100 - µV Amplifier Input Impedance (Note 4) - 3 - MΩ Amplifier Large Signal Bandwidth 4.0VP-P Sine Wave Input, to Slew Rate Limited (Note 4) - 1 - MHz Amplifier Small Signal Bandwidth 1.0VP-P Sine Wave Input, to -3dB Loss (Note 4) - 5 - MHz Reference Input Impedance (CTL IN) (Note 4) - 12 - kΩ Reference Input Multiplying Bandwidth (CTL IN) RL = 50Ω, 100mV Sine Wave, to -3dB Loss at IOUT (Note 4) - 75 - MHz DIGITAL INPUTS (D9-D0, CLK, INVERT) Input Logic High Voltage, VIH (Note 5) 2.0 - - V Input Logic Low Voltage, VIL (Note 5) - - 0.8 V Input Logic Current, IIH (Note 5) - - 400 µA Input Logic Current, IIL (Note 5) - - 700 µA Digital Input Capacitance, CIN (Note 4) - 3.0 - pF TIMING CHARACTERISTICS Data Setup Time, tSU See Figure 1 (Note 4) 3 2.0 - ns Data Hold Time, tHLD See Figure 1 (Note 4) 0.5 0.25 - ns Propagation Delay Time, tPD See Figure 1 (Note 4) - 4.5 - ns CLK Pulse Width, tPW1, tPW2 See Figure 1 (Note 4) 1.0 0.85 - ns POWER SUPPLY CHARACTERISTICS IVEEA (Note 5) - 42 50 mA IVEED (Note 5) - 75 95 mA IVCCD (Note 5) - 13 20 mA Power Dissipation (Note 5) - 650 - mW Power Supply Rejection Ratio VCC ±5%, VEE ±5% - 5 - µA/V NOTES: 2. Dissipation rating assumes device is mounted with all leads soldered to printed circuit board. 3. 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. 4. Parameter guaranteed by design or characterization and not production tested. 5. All devices are 100% tested at 25oC. 6. Dynamic Range must be limited to a 1V swing within the compliance range. 7. In testing MTPR, tone frequencies ranged from 1.95MHz to 3.05MHz. The ratio is measured as the range from peak power to peak distortion in the region of removed tones. 3-4 HI5741 Timing Diagrams 50% CLK D13-D0 GLITCH AREA = 1/2 (H x W) V ERROR BAND HEIGHT (H) IOUT tPD t(ps) WIDTH (W) tSETT FIGURE 1. FULL SCALE SETTLING TIME DIAGRAM tPW1 FIGURE 2. PEAK GLITCH AREA (SINGLET) MEASUREMENT METHOD tPW2 50% CLK tSU tSU tHLD tSU tHLD tHLD D13-D0 tPD tSETT IOUT tPD tSETT tPD tSETT FIGURE 3. PROPAGATION DELAY, SETUP TIME, HOLD TIME AND MINIMUM PULSE WIDTH DIAGRAM 3-5 HI5741 Typical Performance Curves -1.17 670 -1.18 660 -1.19 -1.20 -1.21 640 (V) (mW) 650 630 -1.22 -1.23 -1.24 620 -1.25 NOTE: CLOCK FREQUENCY DOES NOT ALTER POWER DISSIPATION 610 600 -50 -40 -30 -20 -10 0 10 20 30 40 50 -1.26 60 70 -1.27 -50 -40 -30 -20 -10 80 90 TEMPERATURE (oC) FIGURE 4. TYPICAL POWER DISSIPATION OVER TEMPERATURE 10 20 30 40 50 60 70 80 90 FIGURE 5. TYPICAL REFERENCE VOLTAGE OVER TEMPERATURE 1.5 0.8 1.0 0.5 0.5 0.25 (LSB) (LSB) 0 TEMPERATURE (oC) 0 0 -0.5 -0.25 -1.0 -0.5 -1.5 0 5000 10,000 -0.8 15,000 0 5000 CODE 10,000 15,000 CODE FIGURE 6. TYPICAL INL PERFORMANCE FIGURE 7. TYPICAL DNL PERFORMANCE 40 4.2 35 4.0 3.8 30 3.6 3.4 (%) (µA) 25 20 3.2 3.0 15 2.8 10 2.6 5 0 -50 -40 -30 -20 -10 2.4 0 10 20 30 40 50 60 TEMPERATURE (oC) FIGURE 8. TYPICAL OFFSET CURRENT OVER TEMPERATURE 3-6 70 80 90 2.2 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 TEMPERATURE (oC) FIGURE 9. TYPICAL GAIN ERROR OVER TEMPERATURE HI5741 (Continued) 90 90 85 85 80 80 (dBc) (dBc) Typical Performance Curves 75 70 75 70 65 65 fOUT = (1/10) fCLK 60 10 fOUT = (1/5) fCLK 20 30 40 50 60 60 70 80 90 100 10 20 fCLK (MSPS) FIGURE 10. SFDR vs CLOCK FREQUENCY 50 60 70 80 90100 82 80 80 76 78 76 74 74 72 (dBc) (dBc) 40 FIGURE 11. SFDR vs CLOCK FREQUENCY 82 70 68 72 70 68 66 64 30 fCLK (MSPS) 66 64 fCLK = 50 MSPS 62 fCLK = 75 MSPS 62 1 5 1 10 fOUT (MSPS) 5 10 15 fOUT (MHz) FIGURE 12. SFDR vs fOUT FIGURE 13. SFDR vs fOUT 80 -72 fOUT = 2.03MHz 78 -74 76 3RD HARMONIC -76 72 (dBc) (dBc) 74 70 -78 -80 2ND HARMONIC 68 -82 66 64 -84 fCLK = 100 MSPS 62 -86 1 5 fOUT (MHz) FIGURE 14. SFDR vs fOUT 3-7 10 15 20 10 20 30 40 50 60 70 80 90100 fCLK (MSPS) FIGURE 15. HARMONIC DISTORTION vs CLOCK FREQUENCY HI5741 Typical Performance Curves (Continued) 10dB/ 10dB/ fCLK = 20 MSPS fCLK = 100 MSPS fOUT = 26.6MHz SFDR = 77.5dBc MTPR = 75.17dBc S S C C START 1.900MHz STOP 3.100MHz CENTER 26.637MHz SPAN 2.000MHz FIGURE 17. SFDR WITHIN A WINDOW FIGURE 16. TYPICAL MTPR PERFORMANCE 12-BIT WINDOW ∆: 240µV @: -30.96mV ∆: 300µV @: -124.1mV SETTLING TIME ~10ns 1 1 GLITCH = (0.5) • (300µV) • (3.3ns) = 0.495pV/s CH1 1.00mV~ M 5.0ns CH1 -16.9mV FIGURE 18. TYPICAL SETTLING TIME PERFORMANCE CH1 1.00mV M 5.0ns CH1 -109mV FIGURE 19. TYPICAL GLITCH ENERGY Pin Descriptions PIN NO. 1-14 PIN NAME PIN DESCRIPTION D13 (MSB) thru D0 Digital Data Bit 13, the Most Significant Bit through Digital Data Bit 0, the Least Significant Bit. (LSB) 15 CLK 16 DVCC Digital Logic Supply +5V. Data Clock Pin 100kHz to 100 MSPS. 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 (VREFOUT /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 AMP IN Input to the current source base rail. Typically connected to CTRL AMP OUT and a 0.1µF capacitor to AVEE. Allows external control of the current sources. 25 CTRL AMP OUT Control amplifier out. Provides precision control of the current sources when connected to CTRL AMP IN such that IFS = 16 x (VREFOUT /RSET). 26 REF OUT -1.23V (typical) bandgap reference voltage output. Can sink up to 500µA or be overdriven by an external reference capable of delivering up to 2mA. 3-8 HI5741 Detailed Description The HI5741 is a 14-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 14-bit levels. The HI5741 achieves its low power and high speed performance from an advanced BiCMOS process. The HI5741 consumes 650mW (typical) and has an improved hold time of only 0.25ns (typical). The HI5741 is an excellent converter for use in communications applications and high performance video systems. Digital Inputs The HI5741 is a TTL/CMOS compatible D/A. Data is latched by a Master register. Once latched, data inputs D0 (LSB) through D13 (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) through D9 directly drive a typical R/2R network to create the binary weighted current sources. Bits D10 through D13 (MSB) pass through 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 14-bit register is updated on the rising edge of the clock. Since the HI5741 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, 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 HI5741 CLK pin as possible. ZO = 50Ω CLK HI5741 DAC RT = 50Ω FIGURE 20. HI5741 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 HI5741 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. Reduction of digital noise (caused by high slew rates on the bit inputs to the HI5741) can be accomplished through the use of series termination resistors. The use of serial resistors, which combine with the input capacitance of the HI5741 to induce a low pass filter characteristic, keeps the noise generated by high slew rate digital signals from corrupting the high accuracy analog data. Refer to Application Note AN9619 “Optimizing setup conditions for high accuracy measurements of the HI5741” for further details on selecting the proper value of series termination to meet application specific needs. Reference The internal reference of the HI5741 is a -1.23V (typical) bandgap voltage reference with 50µV/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 21 illustrates a typical external reference configuration. HI5741 (26) REF OUT -1.25V R -5.2V FIGURE 21. EXTERNAL REFERENCE CONFIGURATION 3-9 HI5741 Multiplying Capability The HI5741 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 22. AVEE VIN HI5741 CIN (OPTIONAL) REF OUT RSET FIGURE 22. 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 a 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 23. HI5741 CTRL OUT C2 200Ω VIN fIN C1 C2 100kHz 0.01µF 1µF >1MHz 0.001µF 0.1µF 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. CTRL OUT CTRL IN 0.01µF TABLE 1. CAPACITOR SELECTION AVEE 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 14 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. C1 CTRL IN 50Ω FIGURE 23. HIGH FREQUENCY MULTIPLYING BANDWIDTH CIRCUIT The nominal input/output relationship is defined as: ∆V IN ∆I OUT = -------------80Ω 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 23 can be tuned to adjust the lower cutoff frequency by adjusting capacitor values. Table 1 below illustrates the relationship: 3-10 TABLE 2. INPUT CODING vs CURRENT OUTPUT INPUT CODE (D13-D0) IOUT (mA) IOUT (mA) 11 1111 1111 1111 -20.48 0 10 0000 0000 0000 -10.24 -10.24 00 0000 0000 0000 0 -20.48 Settling Time The settling time of the HI5741 is measured as the time it takes for the output of the DAC to settle to within a defined error band of its final value during a 1/16th (code 0000... to 0001 0000.... or 1111... to 1110 1111...) scale transition. In defining settling time specifications for the HI5741, two levels of accuracy are considered. The accuracy levels defined for the HI5741 are 12 (or 0.024%) and 13 (0.012%) bits. Glitch The output glitch of the HI5741 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 faster than the turn on time (TTL designs). Unequal delay HI5741 paths through the device can also cause one current source to change before another. In order to minimize this, the Intersil HI5741 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 8191 to 8192). However, due to the split architecture of the HI5741, the glitch is moved to the 1023 to 1024 transition (and every subsequent 1024 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. In measuring the output glitch of the HI5741 the output is terminated into a 64Ω load. The glitch is measured at any one of the current cell carry (code 1023 to 1024 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 25 shows the area considered as glitch when changing the DAC output. Units are typically specified in picoVolt/seconds (pV/s). HI5741 (21) IOUT 64Ω 100MHz LOW PASS FILTER SCOPE 50Ω FIGURE 24. GLITCH TEST CIRCUIT 5kΩ REF OUT (26) - + - + 5kΩ 1/ CA2904 2 1/ CA2904 2 0.1µF HI5741 IOUT (21) 60Ω 240Ω 240Ω 50Ω - VOUT + HFA1100 FIGURE 26. 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 27 shows how to interface an HI5741 to the HSP45106. 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. a (mV) GLITCH ENERGY = (a x t)/2 t (ns) FIGURE 25. MEASURING GLITCH ENERGY Applications Bipolar Applications To convert the output of the HI5741 to a bipolar 4V swing, the following applications circuit is recommended. The reference can only provide 125µA of drive, so it must be 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. 3-11 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 volt • 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. HI5741 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. tone spacing of this pattern (∆f) is created such that tones 1 through 4 and 5 through 8 are spaced equally, with tones 4 and 5 spaced at 2∆f. MTPR is measured as the dynamic range from peak power to peak distortion in the 2∆f gap. 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: Multi-Tone Power Ratio, MTPR, is the amplitude difference from peak amplitude to peak distortion (either harmonic or non-harmonic). An 8 tone pattern is loaded into the D/A. The 20Log (RMS of Sum and Difference Distortion Products) IMD = ------------------------------------------------------------------------------------------------------------------------------------------------------( RMS Amplitude of the Fundamental ) U2 33 MSPS CLK BASEBAND BIT STREAM K9 C11 B11 ENCODER C10 A11 F10 F9 F11 H11 G11 G9 J11 G10 D10 CONTROLLER VCC J10 K11 B8 A8 B6 B7 A7 C7 C6 A6 A5 C5 A4 B4 A3 A2 B3 A1 B10 B9 A10 E11 E9 VCC VCC H10 K2 J2 CLK MOD2 MOD1 FILTER U1 MOD0 PMSEL DACSTRB ENPOREG SIN15 ENOFREG SIN14 ENCFREG SIN13 SIN12 ENPHAC SIN11 ENTIREG SIN10 INHOFR SIN9 INITPAC SIN8 INITTAC SIN7 SIN6 TEST SIN5 PARSER SIN4 BINFMT SIN3 SIN2 SIN1 C15_MSB SIN0 C4 C13 C12 C11 C10 COS15 C9 COS14 C8 COS13 COS12 C7 COS11 C6 COS10 C5 COS9 C4 COS8 C3 COS7 C2 COS6 C1 COS5 C0 COS4 A2 COS3 A1 COS2 A0 COS1 CS COS0 WR PACI TICO L1 VCC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 K3 L2 L3 L4 J5 K5 L5 K6 J6 J7 L7 L6 L8 K8 L9 L10 15 R4 50 C2 B1 C1 D1 E3 E2 E1 F2 F3 G3 G1 G2 H1 H2 J1 K1 16 -5.2V_D DVCC IOUT D13 (MSB) D12 D11 IOUT/ D10 D9 C AMP IN D8 D7 D6 C AMP OUT D5 D4 D3 D2 REF OUT D1 D0 (LSB) RSET CLK 21 R1 20 R2 TO RF UP-CONVERT STAGE 64 64 24 25 C2 0.1µF C1 0.01µF -5.2V_A -5.2V_A 26 R3 23 976 28 DGND 17 DGND ARET 18 DV EE AVEE 19 AVSS 27 22 -5.2V_A HI5741 L1 -5.2V_D 10µH -5.2V_A L2 10µH B2 OES OEC HSP45106 FIGURE 27. PSK MODULATOR USING THE HI5741 AND HSP45106 16-BIT NCO 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. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries 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 Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see web site www.intersil.com 3-12