ISL5629INZ

DESIGNS DED FOR NEW EN M M O EC R NO T MENT DED REPLACE NO RECOMMEN ter at en C t or cal Supp ni ch Te r ou t ac com/tsc cont or www.intersil. 1-888-INTERSIL ISL5629 DATASHEET Dual 8-bit, +3.3V, 130/210+MSPS, High Speed D/A Converter FN6018 Rev 1.00 February 2002 The ISL5629 is a dual 8-bit, 130/210+MSPS (Mega Samples Per Second), CMOS, high speed, low power, D/A (digital to analog) converter, designed specifically for use in communication systems. Features This device complements the ISL5x61 and ISL5x29 families of high speed converters, which include 8-, 10-, 12-, and 14bit devices. • Adjustable Full Scale Output Current . . . . . 2mA to 20mA Ordering Information • 3V LVCMOS Compatible Inputs TEMP. RANGE (oC) PACKAGE ISL5629IN -40 to 85 48 Ld LQFP Q48.7x7A 130MHz ISL5629/2IN -40 to 85 48 Ld LQFP Q48.7x7A 210MHz PART NUMBER ISL5629EVAL1 25 PKG. NO. Evaluation Platform CLOCK SPEED 210MHz 1 48 47 46 45 44 43 42 41 40 39 38 37 36 (LSB) ID0 2 35 QD1 NC NC 3 34 QD2 4 33 NC 5 32 NC 6 7 31 QD3 QD4 QD5 30 QD6 8 29 9 28 QD7 (MSB) CLK 10 27 DGND 11 12 26 AGND FN6018 Rev 1.00 February 2002 • Excellent Spurious Free Dynamic Range (67dBc to Nyquist, f S = 130MSPS, fOUT = 10MHz) • Dual, 3.3V, Lower Power Replacement for AD9709 Applications • Quadrature Transmit with IF Range 0-80MHz QD0 (LSB) QCOMP AVDD NC QOUTB QOUTA AGND FSADJ REFIO REFLO IOUTA IOUTB 25 13 14 15 16 17 18 19 20 21 22 23 24 AVDD ICOMP NC AGND • +3.3V Power Supply NC NC NC NC NC NC ID7 (MSB) ID4 ID5 ID6 ID3 ID2 ID1 SLEEP DVDD • Guaranteed Gain Matching < 0.14dB • Wireless Communication Systems ISL5629 (LQFP) TOP VIEW NC • Low Power . . . . . 233mW with 20mA Output at 130MSPS • Medical/Test Instrumentation and Equipment Pinout NC • Speed Grades . . . . . . . . . . . . . . . . 130M and 210+MSPS Page 1 of 12 ISL5629 ID2 ID3 ID4 ID5 ID6 ID7 (MSB) NC NC NC NC NC NC Typical Applications Circuit SLEEP DVPP C1 0.1F ICOMP C2 0.1F AVPP 48 47 46 45 44 43 42 41 40 39 38 37 36 1 35 2 34 3 33 4 32 5 31 6 30 7 29 8 CLK 28 9 DGND 27 10 DVDD AGND 26 11 AGND 25 12 13 14 15 16 17 18 19 20 21 22 23 24 REFIO REFLO AGND FSADJ ID1 (LSB) ID0 NC NC NC NC NC NC AVDD AVDD C4 0.1F QD0 (LSB) QD1 QD2 QD3 QD4 QD5 QD6 QD7 (MSB) R1 50 QCOMP C3 0.1F AVPP C5 0.1F C6 0.1F RSET 1.91k 50 R3 R2 50 1:1 TRANSFORMER (50) REPRESENTS ANY 50 LOAD (50) QOUT IOUT BEAD FERRITE + C11 10F L1 10H DVPP (DIGITAL POWER PLANE) = +3.3V C9 0.1F C10 1F C12 0.1F C13 1F +3.3V POWER SOURCE FERRITE BEAD + C14 10F FN6018 Rev 1.00 February 2002 L2 10H AVPP (ANALOG POWER PLANE) = +3.3V Page 2 of 12 ISL5629 Functional Block Diagram NC QOUTA NC QOUTB NC NC NC INPUT LATCH CASCODE NC 34 (LSB) QD0 SWITCH MATRIX 34 CURRENT SOURCE QD1 QD2 3 LSBs QD3 QD4 QD5 QD6 + 31 MSB SEGMENTS UPPER 5-BIT DECODER (MSB) QD7 QCOMP SLEEP INT/EXT VOLTAGE CLK BIAS GENERATION REFERENCE FSADJ REFIO REFLO ICOMP NC NC IOUTA NC NC NC IOUTB INPUT LATCH CASCODE NC 34 (LSB) ID0 SWITCH MATRIX 34 CURRENT SOURCE ID1 ID2 3 LSBs ID3 ID4 ID5 ID6 UPPER 5-BIT + 31 MSB SEGMENTS DECODER (MSB) ID7 FN6018 Rev 1.00 February 2002 Page 3 of 12 ISL5629 Pin Descriptions PIN NO. PIN NAME 11, 19, 26 AGND Analog ground. 13, 24 AVDD Analog supply (+2.7V to +3.6V). 28 CLK Clock input. 27 DGND Connect to digital ground. 10 DVDD Digital supply (+2.7V to +3.6V). 20 FSADJ Full scale current adjust. Use a resistor to ground to adjust full scale output current. Full scale output current = 32 x VFSADJ/RSET. 14, 23 NC 12, 25 ICOMP, QCOMP 1-2, 29-36, 43-48 ID7-ID0, QD7-QD0 15, 22 IOUTA, QOUTA Current outputs of the device. Full scale output current is achieved when all input bits are set to binary 1. 16, 21 IOUTB, QOUTB Complementary current outputs of the device. Full scale output current is achieved on the complementary outputs when all input bits are set to binary 0. 17 REFIO Reference voltage input if Internal reference is disabled. The internal reference is not intended to drive an external load. Use 0.1F cap to ground when internal reference is enabled. 18 REFLO Connect to analog ground to enable internal 1.2V reference or connect to AVDD to disable internal reference. 3-8, 37-42 NC No connect (NC). Not internally connected. No termination required, may be used for device migration to higher resolution DACs. 9 SLEEP FN6018 Rev 1.00 February 2002 PIN DESCRIPTION Not internally connected. Recommend no connect. Compensation pin for internal bias generation. Each pin should be individually decoupled to AGND with a 0.1F capacitor. Digital data input ports. Bit 7 is most significant bit (MSB) and bit 0 is the least significant bit (LSB). Connect to digital ground or leave floating for normal operation. Connect to DVDD for sleep mode. Page 4 of 12 ISL5629 Absolute Maximum Ratings Thermal Information Digital Supply Voltage DVDD to DGND . . . . . . . . . . . . . . . . . . +3.6V Analog Supply Voltage AVDD to AGND . . . . . . . . . . . . . . . . . . +3.6V Grounds, AGND TO DGND . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V Digital Input Voltages (DATA, CLK, SLEEP) . . . . . . . . DVDD + 0.3V Reference Input Voltage Range. . . . . . . . . . . . . . . . . . AVDD + 0.3V Analog Output Current (IOUT) . . . . . . . . . . . . . . . . . . . . . . . . . 24mA Thermal Resistance (Typical, Note 1) JA(°C/W) LQFP Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150°C Maximum Storage Temperature Range . . . . . . . . . . . -65°C to 150°C Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C Operating Conditions Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to 85°C 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. JA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications AVDD = DVDD = +3.3V, VREF = Internal 1.2V, IOUTFS = 20mA, TA = 25°C for All Typical Values TA = -40°C TO 85°C PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 8 - - Bits SYSTEM PERFORMANCE Resolution Integral Linearity Error, INL “Best Fit” Straight Line (Note 7) -0.5 0.05 +0.5 LSB Differential Linearity Error, DNL (Note 7) -0.5 0.05 +0.5 LSB Offset Error, IOS IOUTA (Note 7) +0.006 % FSR Offset Drift Coefficient (Note 7) - 0.1 - ppm FSR/°C Full Scale Gain Error, FSE With External Reference (Notes 2, 7) -3 0.5 +3 % FSR With Internal Reference (Notes 2, 7) -3 0.5 +3 % FSR With External Reference (Note 7) - 50 - ppm FSR/°C With Internal Reference (Note 7) - 100 - ppm FSR/°C fCLK = 100MSPS, fOUT = 10MHz - 83 - dB Full Scale Gain Drift Crosstalk fCLK = 100MSPS, fOUT = 40MHz -0.006 - 74 - dB As a percentage of Full Scale Range -1.6 0.6 +1.6 % FSR In dB Full Scale Range -0.14 0.05 +0.14 dB FSR 2 20 22 mA (Note 3) -1.0 - 1.25 V Maximum Clock Rate, fCLK ISL5629/2IN 210 250 - MHz Maximum Clock Rate, fCLK ISL5629IN 130 150 - MHz Gain Matching Between Channels (DC Measurement) Full Scale Output Current, IFS Output Voltage Compliance Range DYNAMIC CHARACTERISTICS Output Rise Time Full Scale Step - 1 - ns Output Fall Time Full Scale Step - 1 - ns - 5 - pF IOUTFS = 20mA - 50 - pA/Hz IOUTFS = 2mA - 30 - pA/Hz Output Capacitance Output Noise FN6018 Rev 1.00 February 2002 Page 5 of 12 ISL5629 Electrical Specifications AVDD = DVDD = +3.3V, VREF = Internal 1.2V, IOUTFS = 20mA, TA = 25°C for All Typical Values (Continued) TA = -40°C TO 85°C PARAMETER TEST CONDITIONS MIN TYP MAX UNITS AC CHARACTERISTICS (Using Figure 6 with RDIFF = 50 and RLOAD = 50, Full Scale Output = -2.5dBm Spurious Free Dynamic Range, SFDR Within a Window Spurious Free Dynamic Range, SFDR to Nyquist (fCLK/2) fCLK = 210MSPS, fOUT = 80.8MHz, 30MHz Span (Notes 4, 7) - 62 - dBc fCLK = 210MSPS, fOUT = 40.4MHz, 30MHz Span (Notes 4, 7) - 66 - dBc fCLK = 130MSPS, fOUT = 20.2MHz, 20MHz Span (Notes 4, 7) - 66 - dBc fCLK = 210MSPS, fOUT = 80.8MHz (Notes 4, 7) - 50 - dBc fCLK = 210MSPS, fOUT = 40.4MHz (Notes 4, 7, 9) - 58 - dBc fCLK = 200MSPS, fOUT = 20.2MHz, T = 25°C (Notes 4, 7) 56 62 - dBc fCLK = 200MSPS, fOUT = 20.2MHz, T = -40°C to 85°C (Notes 4, 7) 54 - - dBc fCLK = 130MSPS, fOUT = 50.5MHz (Notes 4, 7) - 52 - dBc fCLK = 130MSPS, fOUT = 40.4MHz (Notes 4, 7) - 55 - dBc fCLK = 130MSPS, fOUT = 20.2MHz (Notes 4, 7) - 65 - dBc 63 67 - dBc fCLK = 130MSPS, fOUT = 5.05MHz (Notes 4, 7) - 67 - dBc fCLK = 100MSPS, fOUT = 40.4MHz (Notes 4, 7) - 56 - dBc fCLK = 80MSPS, fOUT = 30.3MHz (Notes 4, 7) - 59 - dBc fCLK = 130MSPS, fOUT = 10.1MHz, T = -40°C to 85°C (Notes 4, 7) fCLK = 80MSPS, fOUT = 20.2MHz (Notes 4, 7) - 66 - dBc fCLK = 80MSPS, fOUT = 10.1MHz (Notes 4, 7, 9) - 66 - dBc fCLK = 80MSPS, fOUT = 5.05MHz (Notes 4, 7) - 67 - dBc fCLK = 50MSPS, fOUT = 20.2MHz (Notes 4, 7) - 60 - dBc fCLK = 50MSPS, fOUT = 10.1MHz (Notes 4, 7) - 66 - dBc fCLK = 50MSPS, fOUT = 5.05MHz (Notes 4, 7) - 66 - dBc fCLK = 210MSPS, fOUT = 28.3MHz to 45.2MHz, 2.1MHz Spacing, 50MHz Span (Notes 4, 7, 9) - 58 - dBc fCLK = 130MSPS, fOUT = 17.5MHz to 27.9MHz, 1.3MHz Spacing, 35MHz Span (Notes 4, 7) - 60 - dBc fCLK = 80MSPS, fOUT = 10.8MHz to 17.2MHz, 811kHz Spacing, 15MHz Span (Notes 4, 7) - 60 - dBc fCLK = 50MSPS, fOUT = 6.7MHz to 10.8MHz, 490kHz Spacing, 10MHz Span (Notes 4, 7) - 60 - dBc 1.2 1.23 1.3 V - 40 - ppm/°C - 0 - A Reference Input Impedance - 1 - M Reference Input Multiplying Bandwidth (Note 7) - 1.0 - MHz Spurious Free Dynamic Range, SFDR in a Window with Eight Tones VOLTAGE REFERENCE Internal Reference Voltage, VFSADJ Pin 20 Voltage with Internal Reference Internal Reference Voltage Drift Internal Reference Output Current Sink/Source Capability DIGITAL INPUTS Reference is not intended to drive an external load D7-D0, CLK Input Logic High Voltage with 3.3V Supply, VIH (Note 3) 2.3 3.3 - V Input Logic Low Voltage with 3.3V Supply, VIL (Note 3) - 0 1.0 V Sleep Input Current, IIH -25 - +25 A Input Logic Current, IIH, IL -20 - +20 A FN6018 Rev 1.00 February 2002 Page 6 of 12 ISL5629 Electrical Specifications AVDD = DVDD = +3.3V, VREF = Internal 1.2V, IOUTFS = 20mA, TA = 25°C for All Typical Values (Continued) TA = -40°C TO 85°C PARAMETER TEST CONDITIONS Clock Input Current, IIH, IL Digital Input Capacitance, CIN MIN TYP MAX UNITS -10 - +10 A - 3 - pF TIMING CHARACTERISTICS Data Setup Time, tSU See Figure 8 - 1.5 - ns Data Hold Time, tHLD See Figure 8 - 1.5 - ns Propagation Delay Time, tPD See Figure 8 - 1 - Clock Period CLK Pulse Width, tPW1 , tPW2 See Figure 8 (Note 3) 2 - - ns POWER SUPPLY CHARACTERISTICS AVDD Power Supply (Note 8) 2.7 3.3 3.6 V DVDD Power Supply (Note 8) 2.7 3.3 3.6 V Analog Supply Current (IAVDD) 3.3V, IOUTFS = 20mA - 60 62 mA 3.3V, IOUTFS = 2mA - 24 - mA 3.3V (Note 5) - 11 15 mA 3.3V (Note 6) - 17 21 mA Supply Current (IAVDD) Sleep Mode 3.3V, IOUTFS = Don’t Care - 5 - mA Power Dissipation 3.3V, IOUTFS = 20mA (Note 5) - 233 255 mW 3.3V, IOUTFS = 20mA (Note 6) - 253 274 mW 3.3V, IOUTFS = 2mA (Note 5) - 115 - mW -0.125 - +0.125 %FSR/V Digital Supply Current (IDVDD) Power Supply Rejection Single Supply (Note 7) NOTES: 2. Gain Error measured as the error in the ratio between the full scale output current and the current through RSET (typically 625A). Ideally the ratio should be 32. 3. Parameter guaranteed by design or characterization and not production tested. 4. Spectral measurements made with differential transformer coupled output and no external filtering. For multitone testing, the same pattern was used at different clock rates, producing different output frequencies but at the same ratio to the clock rate. 5. Measured with the clock at 130MSPS and the output frequency at 10MHz. 6. Measured with the clock at 200MSPS and the output frequency at 20MHz. 7. See Definition of Specifications. 8. Recommended operation is from 3.0V to 3.6V. Operation below 3.0V is possible with some degradation in spectral performance. Reduction in analog output current may be necessary to maintain spectral performance. 9. See Typical Performance plots. FN6018 Rev 1.00 February 2002 Page 7 of 12 ISL5629 Typical Performance (+3.3V Supply, Using Figure 6 with RDIFF = 100 and RLOAD = 50) FIGURE 1. ONE TONE AT 10.1MHz, 80MSPS CLOCK (66dBc - NYQUIST, 6dB PAD) FIGURE 2. ONE TONE AT 40.4MHz, 210MSPS CLOCK (56dBc - NYQUIST, 6dB PAD) FIGURE 3. EIGHT TONES (CREST FACTOR=8.9) AT 37MHz, 210MSPS CLOCK, 2.1MHz SPACING (57dBc - NYQUIST) FIGURE 4. TWO TONES (CF=6) AT 8.5MHz, 50MSPS CLOCK, 500kHz SPACING (67dBc - 10MHz WINDOW, 6dB PAD) FIGURE 5. FOUR TONES (CF=8.1) AT 14MHz, 80MSPS CLOCK, 800kHz SPACING (61dBc - NYQUIST, 6dB PAD) FN6018 Rev 1.00 February 2002 Page 8 of 12 ISL5629 Definition of Specifications Crosstalk, is the measure of the channel isolation from one DAC to the other. It is measured by generating a sinewave in one DAC while the other DAC is clocked with a static input, and comparing the output power of each DAC at the frequency generated. Differential Linearity Error, DNL, is the measure of the step size output deviation from code to code. Ideally the step size should be one LSB. A DNL specification of one LSB or less guarantees monotonicity. EDGE, Enhanced Data for Global Evolution, a TDMA standard for cellular applications which uses 200kHz BW, 8-PSK modulated carriers. Full Scale Gain Drift, is measured by setting the data inputs to be all logic high (all 1s) and measuring the output voltage through a known resistance as the temperature is varied from TMIN to TMAX . It is defined as the maximum deviation from the value measured at room temperature to the value measured at either TMIN or TMAX . The units are ppm of FSR (full scale range) per °C. Full Scale Gain Error, is the error from an ideal ratio of 32 between the output current and the full scale adjust current (through RSET). Gain Matching, is a measure of the full scale amplitude match between the I and Q channels given the same input pattern. It is typically measured with all 1s at the input to both channels, and the full scale output voltage developed into matching loads is compared for the I and Q outputs. 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. Internal Reference Voltage Drift, is defined as the maximum deviation from the value measured at room temperature to the value measured at either TMIN or TMAX . The units are ppm per °C. Offset Drift, is measured by setting the data inputs to all logic low (all 0s) and measuring the output voltage at IOUTA through a known resistance as the temperature is varied from TMIN to TMAX . It is defined as the maximum deviation from the value measured at room temperature to the value measured at either TMIN or TMAX . The units are ppm of FSR (full scale range) per degree °C. Offset Error, is measured by setting the data inputs to all logic low (all 0s) and measuring the output voltage of IOUTA through a known resistance. Offset error is defined as the maximum deviation of the IOUTA output current from a value of 0mA. Output Voltage Compliance Range, is the voltage limit imposed on the output. The output impedance should be FN6018 Rev 1.00 February 2002 chosen such that the voltage developed does not violate the compliance range. Power Supply Rejection, is measured using a single power supply. The nominal supply voltage is varied 10% and the change in the DAC full scale output is noted. Reference Input Multiplying Bandwidth, is defined as the 3dB bandwidth of the voltage reference input. It is measured by using a sinusoidal waveform as the external reference with the digital inputs set to all 1s. The frequency is increased until the amplitude of the output waveform is 0.707 (-3dB) of its original value. Spurious Free Dynamic Range, SFDR, is the amplitude difference from the fundamental signal to the largest harmonically or non-harmonically related spur within the specified frequency window. Total Harmonic Distortion, THD, is the ratio of the RMS value of the fundamental output signal to the RMS sum of the first five harmonic components. Detailed Description The ISL5629 is a dual 8-bit, current out, CMOS, digital to analog converter. The maximum update rate is at least 210+MSPS and can be powered by a single power supply in the recommended range of +3.0V to +3.6V. Operation with clock rates higher than 210MSPS is possible; please contact the factory for more information. It consumes less than 125mW of power per channel when using a +3.3V supply, the maximum 20mA of output current, and the data switching at 210MSPS. The architecture is based on a segmented current source arrangement that reduces glitch by reducing the amount of current switching at any one time. In previous architectures that contained all binary weighted current sources or a binary weighted resistor ladder, the converter might have a substantially larger amount of current turning on and off at certain, worst-case transition points such as midscale and quarter scale transitions. By greatly reducing the amount of current switching at these major transitions, the overall glitch of the converter is dramatically reduced, improving settling time, transient problems, and accuracy. Digital Inputs and Termination The ISL5629 digital inputs are formatted as offset binary and guaranteed to 3V LVCMOS levels. The internal register is updated on the rising edge of the clock. To minimize reflections, proper termination should be implemented. If the lines driving the clock and the digital inputs are long 50 lines, then 50 termination resistors should be placed as close to the converter inputs as possible connected to the digital ground plane (if separate grounds are used). These termination resistors are not likely needed as long as the digital waveform source is within a few inches of the DAC. For pattern drivers with very high speed edge rates, it is recommended that the user consider series termination (50- Page 9 of 12 ISL5629 200prior to the DAC’s inputs in order to reduce the amount of noise. Power Supply Separate digital and analog power supplies are recommended. The allowable supply range is +2.7V to +3.6V. The recommended supply range is +3.0 to 3.6V (nominally +3.3V) to maintain optimum SFDR. However, operation down to +2.7V is possible with some degradation in SFDR. Reducing the analog output current can help the SFDR at +2.7V. The SFDR values stated in the table of specifications were obtained with a +3.3V supply. Ground Planes Separate digital and analog ground planes should be used. All of the digital functions of the device and their corresponding components should be located over the digital ground plane and terminated to the digital ground plane. The same is true for the analog components and the analog ground plane. Noise Reduction To minimize power supply noise, 0.1F capacitors should be placed as close as possible to the converter’s power supply pins, AVDD and DVDD . Also, the layout should be designed using separate digital and analog ground planes and these capacitors should be terminated to the digital ground for DVDD and to the analog ground for AVDD . Additional filtering of the power supplies on the board is recommended. Voltage Reference The internal voltage reference of the device has a nominal value of +1.23V with a 40ppm/°C drift coefficient over the full temperature range of the converter. It is recommended that a 0.1F capacitor be placed as close as possible to the REFIO pin, connected to the analog ground. The REFLO pin selects the reference. The internal reference can be selected if REFLO is tied low (ground). If an external reference is desired, then REFLO should be tied high (the analog supply voltage) and the external reference driven into REFIO. The full scale output current of the converter is a function of the voltage reference used and the value of RSET. IOUT should be within the 2mA to 22mA range, though operation below 2mA is possible, with performance degradation. If the internal reference is used, VFSADJ will equal approximately 1.2V. If an external reference is used, VFSADJ will equal the external reference. The calculation for IOUT (Full Scale) is: IOUT(Full Scale) = (VFSADJ/RSET) X 32. If the full scale output current is set to 20mA by using the internal voltage reference (1.23V) and a 1.91k RSET resistor, then the input coding to output current will resemble the following: FN6018 Rev 1.00 February 2002 TABLE 1. INPUT CODING vs OUTPUT CURRENT WITH INTERNAL REFERENCE (1.23V TYP) AND RSET=1.91K INPUT CODE (D7-D0) IOUTA (mA) IOUTB (mA) 1111 1111 20.6 0 1000 0000 10.3 10.3 0000 0000 0 20.6 Analog Output IOUTA and IOUTB are complementary current outputs. The sum of the two currents is always equal to the full scale output current minus one LSB. If single ended use is desired, a load resistor can be used to convert the output current to a voltage. It is recommended that the unused output be either grounded or equally terminated. The voltage developed at the output must not violate the output voltage compliance range of -1.0V to 1.25V. ROUT (the impedance loading each current output) should be chosen so that the desired output voltage is produced in conjunction with the output full scale current. If a known line impedance is to be driven, then the output load resistor should be chosen to match this impedance. The output voltage equation is: VOUT = IOUT X ROUT. The most effective method for reducing the power consumption is to reduce the analog output current, which dominates the supply current. The maximum recommended output current is 20mA. Differential Output IOUTA and IOUTB can be used in a differential-to-singleended arrangement to achieve better harmonic rejection. With RDIFF= 50and RLOAD=50, the circuit in Figure 6 will provide a 500mV (-2.5dBm) signal at the output of the transformer if the full scale output current of the DAC is set to 20mA (used for the electrical specifications table). Values of RDIFF= 100and RLOAD=50 were used for the typical performance curves to increase the output power and the dynamic range. The center tap in Figure 6 must be grounded. In the circuit in Figure 7, the user is left with the option to ground or float the center tap. The DC voltage that will exist at either IOUTA or IOUTB if the center tap is floating is IOUTDC x (RA//RB) V because RDIFF is DC shorted by the transformer. If the center tap is grounded, the DC voltage is 0V. Recommended values for the circuit in Figure 7 are RA=RB=50, RDIFF=100, assuming RLOAD=50. The performance of Figure 6 and Figure 7 is basically the same, however leaving the center tap of Figure 7 floating allows the circuit to find a more balanced virtual ground, theoretically improving the even order harmonic rejection, but likely reducing the signal swing available due to the output voltage compliance range limitations. Page 10 of 12 ISL5629 Propagation Delay REQ = 0.5 x (RLOAD // RDIFF) AT EACH OUTPUT OUTA RDIFF ISL5629 The converter requires two clock rising edges for data to be represented at the output. Each rising edge of the clock captures the present data word and outputs the previous data. The propagation delay is therefore 1/CLK, plus