19-2777; Rev 2; 12/03 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs Single 3.3V Supply Operation Excellent SFDR and IMD Performance SFDR = 76dBc at fOUT = 30MHz (to Nyquist) IMD = -85dBc at fOUT = 10MHz ACLR = 72dB at fOUT = 61MHz 2mA to 20mA Full-Scale Output Current Differential, LVDS-Compatible Digital and Clock Inputs On-Chip 1.2V Bandgap Reference Low 130mW Power Dissipation 68-Lead QFN-EP Package Ordering Information PART TEMP RANGE Digital Signal Synthesis Automated Test Equipment (ATE) Instrumentation 63 62 61 60 59 58 B8N B8P B7P B7N B6P B6N B5P DVDD DGND B4N 67 66 65 64 B4P 68 B3P B2P B3N B2N TOP VIEW Applications Communications: LMDS, MMDS, Point-to-Point Microwave 68 QFN-EP* Pin Configuration Refer to the MAX5886 and MAX5888 data sheets for pin-compatible 12- and 16-bit versions of the MAX5887. Base Stations: Single/Multicarrier UMTS, CDMA, GSM PIN-PACKAGE MAX5887EGK -40C to +85C *EP = Exposed paddle. B5N The digital and clock inputs of the MAX5887 are designed for differential low-voltage differential signal (LVDS)-compatible voltage levels. The MAX5887 is available in a 68-pin QFN package with an exposed paddle (EP) and is specified for the extended industrial temperature range (-40C to +85C). 500Msps Output Update Rate DGND The MAX5887 is an advanced, 14-bit, 500Msps digitalto-analog converter (DAC) designed to meet the demanding performance requirements of signal synthesis applications found in wireless base stations and other communications applications. Operating from a single 3.3V supply, this DAC offers exceptional dynamic performance such as 76dBc spurious-free dynamic range (SFDR) at f OUT = 30MHz. The DAC supports update rates of 500Msps and a power dissipation of only 230mW. The MAX5887 utilizes a current-steering architecture, which supports a full-scale output current range of 2mA to 20mA, and allows a differential output voltage swing between 0.1VP-P and 1VP-P. The MAX5887 features an integrated 1.2V bandgap reference and control amplifier to ensure high accuracy and low noise performance. Additionally, a separate reference input pin enables the user to apply an external reference source for optimum flexibility and to improve gain accuracy. Features 57 56 55 54 53 52 EP B1P 1 B1N 2 50 B9P B0P 3 49 B10N B0N 4 48 B10P N.C. 5 47 B11N N.C. 6 46 B11P N.C. 7 45 B12N N.C. 8 DGND 9 51 B9N 44 B12P MAX5887 43 B13N DVDD 10 42 B13P VCLK 11 41 DGND CLKGND 12 40 DVDD CLKP 13 39 SEL0 CLKN 14 38 N.C. CLKGND 15 37 N.C. VCLK 16 36 N.C. PD 17 35 N.C. N.C. AGND AVDD AGND AVDD AVDD AGND IOUTP IOUTN AVDD AGND N.C. DACREF FSADJ REFIO AVDD AGND 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 QFN ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 MAX5887 General Description MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs ABSOLUTE MAXIMUM RATINGS AVDD, DVDD, VCLK to AGND................................-0.3V to +3.9V AVDD, DVDD, VCLK to DGND ...............................-0.3V to +3.9V AVDD, DVDD, VCLK to CLKGND ...........................-0.3V to +3.9V AGND, CLKGND to DGND....................................-0.3V to +0.3V DACREF, REFIO, FSADJ to AGND.............-0.3V to AVDD + 0.3V IOUTP, IOUTN to AGND................................-1V to AVDD + 0.3V CLKP, CLKN to CLKGND...........................-0.3V to VCLK + 0.3V B0P/B0N-B13P/B13N, SEL0, PD to DGND ...........................................-0.3V to DVDD + 0.3V Continuous Power Dissipation (TA = +70C) 68-Pin QFN-EP (derate 41.7mW/C above +70C) ......3333mW Thermal Resistance (JA) ..............................................+24C/W Operating Temperature Range ..........................-40C to +85C Junction Temperature .....................................................+150C Storage Temperature Range ............................-60C to +150C Lead Temperature (soldering, 10s) ................................+300C Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0, external reference, VREFIO = 1.25V, differential transformer-coupled analog output, 50 double terminated (Figure 7), IOUT = 20mA, TA = TMIN to TMAX, unless otherwise noted. +25C guaranteed by production test, <+25C guaranteed by design and characterization. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS STATIC PERFORMANCE Resolution 14 Bits LSB Integral Nonlinearity INL Measured differentially 0.8 Differential Nonlinearity DNL Measured differentially 0.5 Offset Error OS -0.025 GEFS Gain Drift Full-Scale Output Current LSB +0.025 50 Offset Drift Full-Scale Gain Error 0.01 IOUT Min Output Voltage Max Output Voltage External reference, TA +25C -3.5 100 External reference 50 (Note 1) ppm/C +1.5 Internal reference 2 -0.5 Single ended % FS ppm/C 20 Single ended % FS mA V 1.1 V Output Resistance ROUT 1 M Output Capacitance COUT 5 pF DYNAMIC PERFORMANCE Output Update Rate fCLK Noise Spectral Density Spurious-Free Dynamic Range to Nyquist 2 SFDR 1 500 fCLK = 100MHz fOUT = 16MHz, -12dB FS -157 fCLK = 200MHz fOUT = 80MHz, -12dB FS -157 fCLK = 100MHz fOUT = 1MHz, 0dB FS 88 fOUT = 1MHz, -6dB FS 89 fOUT = 1MHz, -12dB FS 80 _______________________________________________________________________________________ Msps dB FS/ Hz dBc 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs (AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0, external reference, VREFIO = 1.25V, differential transformer-coupled analog output, 50 double terminated (Figure 7), IOUT = 20mA, TA = TMIN to TMAX, unless otherwise noted. +25C guaranteed by production test, <+25C guaranteed by design and characterization. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS fCLK = 100MHz Spurious-Free Dynamic Range to Nyquist fCLK = 200MHz TYP 81 fOUT = 30MHz, -12dB FS 76 fOUT = 10MHz, -12dB FS 71 fOUT = 16MHz, -12dB FS, TA +25C 69 fOUT = 50MHz, -12dB FS 72 64 fOUT = 10MHz, -12dB FS 66 fOUT = 30MHz, -12dB FS 63 fOUT = 50MHz, -12dB FS 65 fOUT = 80MHz, -12dB FS 59 fCLK = 100MHz fOUT1 = 9MHz, -6dB FS, fOUT2 = 10MHz, -6dB FS -85 fCLK = 200MHz fOUT1 = 79MHz, -6dB FS, fOUT2 = 80MHz, -6dB FS -61 TTIMD MAX UNITS 76 fOUT = 80MHz, -12dB FS SFDR fCLK = 500MHz 2-Tone IMD MIN fOUT = 10MHz, -12dB FS dBc dBc 4-Tone IMD, 1MHz Frequency Spacing, GSM Model FTIMD fCLK = 300MHz fOUT = 32MHz, -12dB FS -78 dBc Adjacent Channel Leakage Power Ratio, 4.1MHz Bandwidth, WCDMA Model ACLR fCLK = 184.32MHz fOUT = 61.44MHz 72 dB 450 MHz Output Bandwidth BW-1dB (Note 2) REFERENCE Internal Reference Voltage Range VREFIO Reference Voltage Drift TCOREF Reference Input Compliance Range VREFIOCR Reference Input Resistance RREFIO 1.12 1.22 1.32 50 0.1 V ppm/C 1.25 V 10 k ANALOG OUTPUT TIMING Output Fall Time Output Rise Time Output Voltage Settling Time Output Propagation Delay tFALL 90% to 10% (Note 3) 375 ps tRISE 10% to 90% (Note 3) 375 ps Output settles to 0.025% FS (Note 3) 11 ns (Note 3) 1.8 ns 1 pV-s IOUT = 2mA 30 IOUT = 20mA 30 tSETTLE tPD Glitch Energy Output Noise NOUT pA/Hz TIMING CHARACTERISTICS Data to Clock Setup Time tSETUP Referenced to rising edge of clock (Note 4) -0.8 ns Data to Clock Hold Time tHOLD Referenced to rising edge of clock (Note 4) 1.8 ns _______________________________________________________________________________________ 3 MAX5887 ELECTRICAL CHARACTERISTICS (continued) MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs ELECTRICAL CHARACTERISTICS (continued) (AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0, external reference, VREFIO = 1.25V, differential transformer-coupled analog output, 50 double terminated (Figure 7), IOUT = 20mA, TA = TMIN to TMAX, unless otherwise noted. +25C guaranteed by production test, <+25C guaranteed by design and characterization. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Data Latency 3.5 Clock cycles Minimum Clock Pulse Width High tCH CLKP, CLKN Minimum Clock Pulse Width Low tCL CLKP, CLKN LVDS LOGIC INPUTS (B0N-B13N, B0P-B13P) 0.9 0.9 ns ns Differential Input Logic High Differential Input Logic Low Common-Mode Voltage Range VIH 100 mV VIL -100 VCOM 1.125 Differential Input Resistance RIN 85 Input Capacitance CIN 100 mV 1.375 V 125 5 pF CMOS LOGIC INPUTS (PD, SEL0) Input Logic High VIH Input Logic Low VIL Input Leakage Current IIN Input Capacitance CIN 0.7 DVDD V 0.3 DVDD -15 +15 5 V A pF CLOCK INPUTS (CLKP, CLKN) Sine wave 1.5 Square wave 0.5 (Note 5) >100 V/s VCOM 1.5 20% V Input Resistance RCLK 5 k Input Capacitance CCLK 5 pF Differential Input Voltage Swing Differential Input Slew Rate Common-Mode Voltage Range VCLK SRCLK VP-P POWER SUPPLIES Analog Supply Voltage Range AVDD 3.135 3.3 3.465 V Digital Supply Voltage Range DVDD 3.135 3.3 3.465 V Clock Supply Voltage Range VCLK 3.135 3.3 3.465 V Analog Supply Current IAVDD Digital Supply Current IDVDD Clock Supply Current 4 IVCLK fCLK = 100Msps, fOUT = 1MHz 27 Power-down 0.3 fCLK = 100Msps, fOUT = 1MHz 6.4 mA mA Power-down 10 A fCLK = 100Msps, fOUT = 1MHz 5.5 mA Power-down 10 A _______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs (AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0, external reference, VREFIO = 1.25V, differential transformer-coupled analog output, 50 double terminated (Figure 7), IOUT = 20mA, TA = TMIN to TMAX, unless otherwise noted. +25C guaranteed by production test, <+25C guaranteed by design and characterization. Typical values are at TA = +25C.) PARAMETER SYMBOL Power Dissipation PDISS Power-Supply Rejection Ratio PSRR Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: CONDITIONS MIN TYP fCLK = 100Msps, fOUT = 1MHz MAX UNITS 130 Power-down mW 1 AVDD = VCLK = DVDD = 3.3V 5% (Note 6) -1 +1 % FS/V Nominal full-scale current IOUT = 32 IREF. This parameter does not include update-rate depending effects of sin(x)/x filtering inherent in the MAX5887. Parameter measured single ended into a 50 termination resistor. Parameter guaranteed by design. A differential clock input slew rate of >100V/s is required to achieve the specified dynamic performance. Parameter defined as the change in midscale output caused by a 5% variation in the nominal supply voltage. Typical Operating Characteristics (AVDD = DVDD = VCLK = 3.3V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, TA = +25C, unless otherwise noted.) 80 90 90 80 70 SFDR (dBc) 60 0dB FS 50 40 SFDR (dBc) 70 -12dB FS 60 -6dB FS 50 0dB FS 40 50 40 30 30 20 20 20 10 10 10 0 0 0 10 20 30 40 50 -12dB FS -6dB FS 60 30 0dB FS 0 10 20 30 40 50 60 70 80 5 90 100 55 105 155 205 255 fOUT (MHz) fOUT (MHz) 2-TONE INTERMODULATION DISTORTION (fCLK = 100MHz) 2-TONE IMD vs. OUTPUT FREQUENCY (1MHz CARRIER SPACING, fCLK = 200MHz) 2-TONE INTERMODULATION DISTORTION (fCLK = 500MHz) -10 -20 fT2 -40 -50 -60 -70 2 x fT2 - fT1 2 x fT1 - fT2 -80 -90 TWO-TONE IMD (dBc) fT1 -30 -100 0 -12dB FS -6dB FS -80 -70 -60 fT1 = 79.095MHz fT2 = 80.3223MHz AOUT = -6dB FS BW = 9MHz -10 -20 OUTPUT POWER (dBm) fT1 = 9.0252MHz fT2 = 10.0417MHz AOUT = -6dB FS BW = 9MHz MAX5887 toc05 0 fT1 -30 MAX5887 toc06 fOUT (MHz) MAX5887 toc04 SFDR (dBc) 70 OUTPUT POWER (dBm) -12dB FS 80 100 MAX5887 toc02 -6dB FS 90 100 MAX5887 toc01 100 SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 500MHz) SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 200MHz) MAX5887 toc03 SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 100MHz) fT2 -40 -50 -60 2 x fT2 - fT1 2 x fT1 - fT2 -70 -80 -90 -90 -50 -100 5 6 7 8 9 10 fOUT (MHz) 11 12 13 14 -100 10 20 30 40 50 fOUT (MHz) 60 70 80 75 76 77 78 79 80 81 82 83 84 fOUT (MHz) _______________________________________________________________________________________ 5 MAX5887 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (AVDD = DVDD = VCLK = 3.3V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, TA = +25C, unless otherwise noted.) SFDR vs. OUTPUT FREQUENCY (fCLK = 300MHz, AOUT = -6dB FS) fOUT = 10MHz 82 60 IOUT = 5mA 40 IOUT = 10mA 1.2 0.9 0.6 fOUT = 40MHz 74 INL (LSB) SFDR (dBc) IOUT = 20mA 1.5 66 MAX5887 toc9 90 INTEGRAL NONLINEARITY vs. DIGITAL INPUT CODE MAX5887 toc08 80 SFDR vs. TEMPERATURE (fCLK = 300MHz, AOUT = -6dB FS, IOUT = 20mA) MAX5887 toc07 100 SFDR (dBc) fOUT = 120MHz 0.3 0 -0.3 -0.6 20 58 -0.9 fOUT = 80MHz 0 -1.2 50 60 90 120 150 -40 fOUT (MHz) -15 10 35 60 85 0.8 0 0.4 0.2 0 -0.2 -0.4 AOUT = -18dB FS BW = 12MHz -10 -20 OUTPUT POWER (dBm) 0.6 10000 14000 8-TONE MULTITONE POWER RATIO PLOT (fCLK = 300MHz, fCENTER = 31.9702MHz) MAX5887 toc10 1.0 DNL (LSB) 6000 DIGITAL INPUT CODE DIFFERENTIAL NONLINEARTIY vs. DIGITAL INPUT CODE fT5 fT1 -30 fT6 fT2 -40 fT3 -50 fT7 fT8 fT4 -60 -70 -80 -0.6 -0.8 -90 -1.0 -100 0 2000 6000 10000 14000 DIGITAL INPUT CODE 26 18000 200 160 120 32 fOUT (MHz) 34 36 38 fT5 = 33.06881MHz fT6 = 34.0209MHz fT7 = 35.0464MHz fT8 = 36.0718MHz 150 145 POWER DISSIPATION (mW) 240 30 POWER DISSIPATION vs. SUPPLY VOLTAGE (fCLK = 100MHz, fOUT = 10MHz, IFS = 20mA) MAX5887 toc12 280 28 fT1 = 28.0151MHz fT2 = 29.0405MHz fT3 = 30.0659MHz fT4 = 31.0181MHz POWER DISSIPATION vs. CLOCK FREQUENCY (fOUT = 10MHz, AOUT = 0dB FS, IOUT = 20mA) 140 EXTERNAL REFERENCE 135 INTERNAL REFERENCE 130 125 80 120 100 200 300 fCLK (MHz) 6 0 2000 TEMPERATURE (C) MAX5887 toc11 30 -1.5 MAX5887 toc13 0 POWER DISSIPATION (mW) MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs 400 500 3.135 3.190 3.245 3.300 3.355 3.410 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 3.465 18000 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs PIN NAME FUNCTION 1 B1P 2 B1N Data Bit 1 Complementary Data Bit 1 3 B0P Data Bit 0 4 B0N Complementary Data Bit 0 5-8, 23, 34-38 N.C. No Connection. Do not connect to these pins. Do not tie these pins together. 9, 41, 60, 62 DGND Digital Ground 10, 40, 61 DVDD Digital Supply Voltage. Accepts a supply voltage range of 3.135V to 3.465V. Bypass each pin with a 0.1F capacitor to the nearest DGND. 11, 16 VCLK Clock Supply Voltage. Accepts a supply voltage range of 3.135V to 3.465V. Bypass each pin with a 0.1F capacitor to the nearest CLKGND. 12, 15 CLKGND 13 CLKP Converter Clock Input. Positive input terminal for the LVDS-compatible differential converter clock. 14 CLKN Complementary Converter Clock Input. Negative input terminal for the LVDS-compatible differential converter clock. 17 PD Power-Down Input. PD pulled high enables the DAC's power-down mode. PD pulled low allows for normal operation of the DAC. This pin features an internal pulldown resistor. 18, 24, 29, 30, 32 AVDD Analog Supply Voltage. Accepts a supply voltage range of 3.135V to 3.465V. Bypass each pin with a 0.1F capacitor to the nearest AGND. 19, 25, 28, 31, 33, EP AGND Analog Ground. Exposed paddle (EP) must be connected to AGND. 20 REFIO Reference I/O. Output of the internal 1.2V precision bandgap reference. Bypass with a 1F capacitor to AGND. Can be driven with an external reference source. 21 FSADJ Full-Scale Adjust Input. This input sets the full-scale output current of the DAC. For 20mA full-scale output current, connect a 2k resistor between FSADJ and DACREF. 22 DACREF Return Path for the Current Set Resistor. For 20mA full-scale output current, connect a 2k resistor between FSADJ and DACREF. 26 IOUTN Complementary DAC Output. Negative terminal for differential current output. The full-scale output current range can be set from 2mA to 20mA. 27 IOUTP DAC Output. Positive terminal for differential current output. The full-scale output current range can be set from 2mA to 20mA. 39 SEL0 Mode Select Input SEL0. Set high to activate the segment shuffling function. Since this pin features an internal pulldown resistor, it can be left open or pulled low to disable the segment-shuffling function. See Segment Shuffling in the Detailed Description section for more information. 42 B13P Data Bit 13 (MSB) 43 B13N Complementary Data Bit 13 (MSB) 44 B12P Data Bit 12 Clock Ground _______________________________________________________________________________________ 7 MAX5887 Pin Description 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs MAX5887 Pin Description (continued) PIN NAME FUNCTION 45 B12N Complementary Data Bit 12 46 B11P Data Bit 11 47 B11N Complementary Data Bit 11 48 B10P Data Bit 10 49 B10N 50 B9P 51 B9N Complementary Data Bit 9 52 B8P Data Bit 8 53 B8N Complementary Data Bit 8 54 B7P Data Bit 7 55 B7N Complementary Data Bit 7 56 B6P Data Bit 6 57 B6N Complementary Data Bit 6 58 B5P Data Bit 5 59 B5N Complementary Data Bit 5 63 B4P Data Bit 4 64 B4N Complementary Data Bit 4 65 B3P Data Bit 3 66 B3N Complementary Data Bit 3 67 B2P Data Bit 2 68 B2N Complementary Data Bit 2 Complementary Data Bit 10 Data Bit 9 Detailed Description Architecture The MAX5887 is a high-performance, 14-bit, currentsteering DAC (Figure 1) capable of operating with clock speeds up to 500MHz. The converter consists of separate input and DAC registers, followed by a currentsteering circuit. This circuit is capable of generating differential full-scale currents in the range of 2mA to 20mA. An internal current-switching network in combination with external 50 termination resistors convert the differential output currents into a differential output voltage with a peak-to-peak output voltage range of 0.1V to 1V. An integrated 1.2V bandgap reference, control amplifier, and user-selectable external resistor determine the data converter's full-scale output range. Reference Architecture and Operation The MAX5887 supports operation with the on-chip 1.2V bandgap reference or an external reference voltage source. REFIO serves as the input for an external, lowimpedance reference source, and as the output if the DAC is operating with the internal reference. For stable 8 operation with the internal reference, REFIO should be decoupled to AGND with a 0.1F capacitor. Due to its limited output drive capability, REFIO must be buffered with an external amplifier, if heavier loading is required. The MAX5887's reference circuit (Figure 2) employs a control amplifier, designed to regulate the full-scale current IOUT for the differential current outputs of the DAC. Configured as a voltage-to-current amplifier, the output current can be calculated as follows: IOUT = 32 IREFIO - 1LSB IOUT = 32 IREFIO - (IOUT / 214) where IREFIO is the reference output current (IREFIO = VREFIO/RSET) and IOUT is the full-scale output current of the DAC. Located between FSADJ and DACREF, RSET is the reference resistor, which determines the amplifier's output current for the DAC. See Table 1 for a matrix of different IOUT and RSET selections. _______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs DGND SEL0 FUNCTION SELECTION BLOCK 1.2V REFERENCE MAX5887 DVDD PD AGND AVDD MAX5887 REFIO IOUTP IOUTN CURRENT-STEERING DAC FSADJ CLKN CLKP SEGMENT SHUFFLING/LATCH DECODER LVDS RECEIVER/INPUT LATCH 14 DIFFERENTIAL DIGITAL INPUTS B0 THROUGH B13 Figure 1. Simplified MAX5887 Block Diagram Table 1. IOUT and RSET Selection Matrix Based on a Typical 1.200V Reference Voltage FULL-SCALE CURRENT IOUT (mA) REFERENCE CURRENT IREF (A) RSET (k) CALCULATED 1% EIA STD OUTPUT VOLTAGE VIOUTP/N* (mVP-P) 2 62.5 19.2 19.1 100 5 156.25 7.68 7.5 250 10 312.5 3.84 3.83 500 15 468.75 2.56 2.55 750 20 625 1.92 1.91 1000 *Terminated into a 50 load. Analog Outputs (IOUTP, IOUTN) The MAX5887 outputs two complementary currents (IOUTP, IOUTN) that can be operated in a singleended or differential configuration. A load resistor can convert these two output currents into complementary single-ended output voltages. The differential voltage existing between IOUTP and IOUTN can also be con- verted to a single-ended voltage using a transformer or a differential amplifier configuration. If no transformer is used, the output should have a 50 termination to the analog ground and a 50 resistor between the outputs. Although not recommended for single-ended operation, because of additional noise pickup from the ground _______________________________________________________________________________________ 9 MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs AVDD 1.2V REFERENCE AVDD CURRENT SOURCES 10k REFIO CURRENT SWITCHES 0.1F IOUTP FSADJ IREF RSET CURRENT-STEERING DAC IOUT IOUTN IOUTN DACREF IOUT IOUTP IREF = VREFIO/RSET Figure 2. Reference Architecture, Internal Reference Configuration plane, IOUTP should be selected as the output, with IOUTN connected to AGND. Note that a single-ended output configuration has a higher 2nd-order harmonic distortion at high output frequencies than a differential output configuration. Figure 3 displays a simplified diagram of the internal output structure of the MAX5887. Figure 3. Simplified Analog Output Structure WIDEBAND RF TRANSFORMER PERFORMS SINGLE-ENDED TO DIFFERENTIAL CONVERSION. 10 CLKP 25 TO DAC 1:1 SINGLE-ENDED CLOCK SOURCE (e.g., HP 8662A) 25 Clock Inputs (CLKP, CLKN) The MAX5887 features a flexible differential clock input (CLKP, CLKN) operating from separate supplies (VCLK, CLKGND) to achieve the lowest possible jitter performance. The two clock inputs can be driven from a single-ended or a differential clock source. For single-ended operation, CLKP should be driven by a logic source, while CLKN should be bypassed to AGND with a 0.1F capacitor. The CLKP and CLKN pins are internally biased to 1.5V. This allows the user to AC-couple clock sources directly to the device without external resistors to define the DC level. The input resistance of CLKP and CLKN is >5k. See Figure 4 for a convenient and quick way to apply a differential signal created from a single-ended source (e.g., HP 8662A signal generator) and a wideband transformer. These inputs can also be driven from an LVDS-compatible clock source; however, it is recommended to use sinewave or AC-coupled ECL drive for best performance. 0.1F 0.1F CLKN CLKGND Figure 4. Differential Clock Signal Generation Data Timing Relationship Figure 5 shows the timing relationship between differential, digital LVDS data, clock, and output signals. The MAX5887 features a 1.8ns hold, a -0.8ns setup, and a 1.8ns propagation delay time. There is a 3.5 clockcycle latency between CLKP/CLKN transitioning high/low and IOUTP/IOUTN. LVDS-Compatible Digital Inputs (B0P-B13P, B0N-B13N) The MAX5887 features LVDS receivers on the bus input interface. These LVDS inputs (B0P/N through B13P/N) allow for a low-differential voltage swing with low constant power consumption across a large range of ______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs B0 TO B15 OUTPUT DATA IS UPDATED ON THE FALLING EDGE OF CLKP N N-1 tSETUP MAX5887 DIGITAL DATA IS LATCHED ON THE RISING EDGE OF CLKP N+1 tHOLD N+2 tCH tCL CLKP CLKN tPD IOUT N-5 N-4 N-3 N-2 N-1 Figure 5. Detailed Timing Relationship frequencies. Their differential characteristic supports the transmission of high-speed data patterns without the negative effects of electromagnetic interference (EMI). All MAX5887 LVDS inputs feature on-chip termination with differential 100 resistors. See Figure 6 for a simplified block diagram of the LVDS inputs. A common-mode level of 1.25V and an 800mV differential input swing can be applied to these inputs. Segment Shuffling (SEL0) Segment shuffling can improve the SFDR of the MAX5887. The improvement is most pronounced at higher output frequencies and amplitudes. Note that an improvement in SFDR can only be achieved at the cost of a slight increase in the DAC's noise floor. Pin SEL0 controls the segment-shuffling function. If SEL0 is pulled low, the segment-shuffling function of the DAC is disabled. SEL0 can also be left open, because an internal pulldown resistor helps to deactivate the segment-shuffling feature. To activate the MAX5887 segment-shuffling function, SEL0 must be pulled high. Power-Down Operation (PD) The MAX5887 also features an active-high power-down mode, which allows the user to cut the DAC's current consumption. A single pin (PD) is used to control the power-down mode (PD = 1) or reactivate the DAC (PD = 0) after power-down. Enabling the power-down mode of the MAX5887 allows the overall power consumption B0P-B13P D Q TO DECODE LOGIC 100 D Q B0N-B13N CLOCK Figure 6. Simplified LVDS-Compatible Input Structure to be reduced to less than 1mW. The MAX5887 requires 10ms to wake up from power-down and enter a fully operational state. Applications Information Differential Coupling Using a Wideband RF Transformer The differential voltage existing between IOUTP and IOUTN can also be converted to a single-ended voltage using a transformer (Figure 7) or a differential amplifier configuration. Using a differential transformercoupled output, in which the output power is limited to 0dBm, can optimize the dynamic performance. However, make sure to pay close attention to the transformer core saturation characteristics when selecting a transformer for the MAX5887. Transformer core saturation can introduce strong 2nd-harmonic distortion, especially at low output frequencies and high signal amplitudes. It is also recommended to center tap the ______________________________________________________________________________________ 11 MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs AVDD DVDD VCLK 50 T2, 1:1 VOUT, SINGLE ENDED IOUTP B0-B13 100 MAX5887 IOUTN 14 T1, 1:1 AGND DGND WIDEBAND RF TRANSFORMER T2 PERFORMS THE DIFFERENTIAL TO SINGLE-ENDED CONVERSION. 50 CLKGND Figure 7. Differential to Single-Ended Conversion Using a Wideband RF Transformer AVDD DVDD VCLK 50 OUTP IOUTP B0-B13 100 MAX5887 IOUTN 14 AGND DGND CLKGND OUTN 50 Figure 8. MAX5887 Differential Output Configuration transformer to ground. If no transformer is used, each DAC output should be terminated to ground with a 50 resistor. Additionally, a 100 resistor should be placed between the outputs (Figure 8). If a single-ended unipolar output is desirable, IOUTP should be selected as the output, with IOUTN grounded. However, driving the MAX5887 single ended is not recommended since additional noise is added (from the ground plane) in such configurations. The distortion performance of the DAC depends on the load impedance. The MAX5887 is optimized for a 50 double termination. It can be used with a transformer output as shown in Figure 7 or just one 50 resistor from each output to ground and one 50 resistor between the outputs. This produces a full-scale output power of up to 0dBm, depending on the output current setting. Higher termination impedance can be used at the cost of degraded distortion performance and increased output noise voltage. 12 Adjacent Channel Leakage Power Ratio (ACLR) Testing for CDMA- and W-CDMA-Based Base Station Transceiver Systems (BTS) The transmitter sections of BTS applications serving CDMA and W-CDMA architectures must generate carriers with minimal coupling of carrier energy into the adjacent channels. Similar to the GSM/EDGE model (see the Multitone Testing for GSM/EDGE Applications section), a transmit mask (Tx mask) exists for this application. The spread-spectrum modulation function applied to the carrier frequency generates a spectral response, which is uniform over a given bandwidth (up to 4MHz) for a W-CDMA-modulated carrier. A dominant specification is ACLR, a parameter which reflects the ratio of the power in the desired carrier band to the power in an adjacent carrier band. The specification covers the first two adjacent bands, and is measured on both sides of the desired carrier. According to the transmit mask for CDMA and W-CDMA architectures, the power ratio of the integrated carrier channel energy to the integrated adjacent channel energy must be >45dB for the first adjacent carrier slot (ACLR 1) and >50dB for the second adjacent carrier slot (ACLR 2). This specification applies to the output of the entire transmitter signal chain. The requirement for only the DAC block of the transmitter must be tighter, with a typical margin of >15dB, requiring the DAC's ACLR 1 to be better than 60dB. Adjacent channel leakage is caused by a single spread-spectrum carrier, which generates intermodulation (IM) products between the frequency components located within the carrier band. The energy at one end of the carrier band generates IM products with the energy from the opposite end of the carrier band. For singlecarrier W-CDMA modulation, these IMD products are spread 3.84MHz over the adjacent sideband. Four con- ______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs The transmitter sections of multicarrier base station transceiver systems for GSM/EDGE usually present communication DAC manufacturers with the difficult task of providing devices with higher resolution, while simultaneously reducing noise and spurious emissions over a desired bandwidth. -25 -30 ANALOG OUTPUT POWER (dBm) -40 fCENTER = 61.44MHz fCLK = 184.32Mbps ACLR = 72dB -50 -60 -70 -80 -90 -100 -25 -30 ANALOG OUTPUT POWER (dBm) Multitone Testing for GSM/EDGE Applications To specify noise and spurious emissions from base stations, a GSM/EDGE Tx mask is used to identify the DAC requirements for these parameters. This mask shows that the allowable levels for noise and spurious emissions are dependent on the offset frequency from the transmitted carrier frequency. The GSM/EDGE mask and its specifications are based on a single active carrier with any other carriers in the transmitter being disabled. Specifications displayed in Figure 11 support per-carrier output power levels of 20W or greater. Lower output power levels yield less-stringent emission requirements. For GSM/EDGE applications, the DAC demands spurious emission levels of less than -80dBc for offset frequencies 6MHz. Spurious products from the DAC can combine with both random noise and spurious products from other circuit elements. The spurious products from the DAC should therefore be backed off by 6dB or more to allow for these other sources and still avoid signal clipping. The number of carriers and their signal levels with respect to the full scale of the DAC are important as well. Unlike a full-scale sine wave, the inherent nature of a multitone signal contains higher peak-to-RMS ratios, raising the prospect for potential clipping, if the signal level is not backed off appropriately. If a transmitter operates with four/eight in-band carriers, each individual carrier must be operated at less than -12dB FS/-18dB FS to avoid waveform clipping. -40 -50 -60 -70 -80 -90 -100 -110 -110 -120 -125 -120 -125 3.5MHz/div Figure 9. ACLR for W-CDMA Modulation, Single Carrier fCENTER = 63.93MHz fCLK = 184.32Mbps ACLR = 66dB 3.5MHz/div Figure 10. ACLR for W-CDMA Modulation, Four Carriers *Note that due to their own IM effects and noise limitations, spectrum analyzers introduce ACLR errors, which can falsify the measurement. For a single-carrier ACLR measurement greater than 70dB, these measurement limitations are significant, becoming even more restricting for multicarrier measurement. Before attempting an ACLR measurement, it is recommended consulting application notes provided by major spectrum analyzer manufacturers that provide useful tips on how to use their instruments for such tests. ______________________________________________________________________________________ 13 MAX5887 tiguous W-CDMA carriers spread their IM products over a bandwidth of 20MHz on either side of the 20MHz total carrier bandwidth. In this four-carrier scenario, only the energy in the first adjacent 3.84MHz side band is considered for ACLR 1. To measure ACLR, drive the converter with a W-CDMA pattern. Make sure that the signal is backed off by the peak-to-average ratio, such that the DAC is not clipping the signal. ACLR can then be measured with the ACLR measurement function built into your spectrum analyzer. Figure 9 shows the ACLR performance for a single W-CDMA carrier (f CLK = 184.32MHz, f OUT = 61.44MHz) applied to the MAX5887 (including measurement system limitations*). Figure 10 illustrates the ACLR test results for the MAX5887 with a four-carrier W-CDMA signal at an output frequency of 63.93MHz and sampling frequency of 184.32MHz. Considerable care must be taken to ensure accurate measurement of this parameter. MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs The noise density requirements (Table 2) for a GSM/EDGE-based system can again be derived from the system's Tx mask. With a worst-case noise level of -80dBc at frequency offsets of 6MHz and a measurement bandwidth of 100kHz, the minimum noise density per hertz is calculated as follows: SNRMIN = -80dBc - 10 log10(100 103Hz) SNRMIN = -130dBc/Hz Since random DAC noise adds to both the spurious tones and to random noise from other circuit elements, it is recommended reducing the specification limits by about 10dB to allow for these additional noise contributions while maintaining compliance with the Tx mask values. Other key factors in selecting the appropriate DAC for the Tx path of a multicarrier GSM/EDGE system is the converter's ability to offer superior IMD and MTPR performance. Multiple carriers in a designated band generate unwanted intermodulation distortion between the individual carrier frequencies. A multitone test vector usually consists of several equally spaced carriers, usually four, with identical amplitudes. Each of these carriers is representative of a channel within the defined bandwidth of interest. To verify MTPR, one or more tones are removed such that the intermodulation distortion performance of the DAC can be evaluated. Nonlinearities associated with the DAC create spurious tones, some of which may fall back into the area of the removed tone, limiting a channel's carrier-to-noise ratio. Other spurious components falling outside the band of interest can also be important, depending on the system's spectral mask and filtering requirements. Going back to the GSM/EDGE Tx mask, the IMD specification for adjacent carriers varies somewhat among the different GSM Table 2. GSM/EDGE Noise Requirements for Multicarrier Systems NUMBER OF CARRIERS CARRIER POWER LEVEL (dB FS) DAC NOISE DENSITY REQUIREMENT (dB FS/Hz) 2 -6 -146 4 -12 -152 8 -18 -158 standards. For the PCS1800 and GSM850 standards, the DAC must meet an average IMD of -70dBc. Table 3 summarizes the dynamic performance requirements for the entire Tx signal chain in a four-carrier GSM/EDGE-based system and compares the previously established converter requirements with a new-generation high dynamic performance DAC. The four-tone MTPR plot in Figure 12 demonstrates the MAX5887's excellent dynamic performance. The center frequency (fCENTER = 32MHz) has been removed to allow detection and analysis of intermodulation or spurious components falling back into this empty spot from adjacent channels. The four carriers are observed over a 12MHz bandwidth and are equally spaced at 1MHz. Each individual output amplitude is backed off to -12dB FS. Under these conditions, the DAC yields an MTPR performance of -78dBc. Grounding, Bypassing, and Power-Supply Considerations Grounding and power-supply decoupling can strongly influence the performance of the MAX5887. Unwanted digital crosstalk may couple through the input, reference, power supply, and ground connections, affecting dynamic performance. Proper grounding and powersupply decoupling guidelines for high-speed, high-fre- Table 3. Summary of Important AC Performance Parameters for Multicarrier GSM/EDGE Systems SPECIFICATION SFDR Noise Spectral Density IMD Carrier Amplitude SYSTEM TRANSMITTER OUTPUT LEVELS DAC REQUIREMENTS WITH MARGINS MAX5887 SPECIFICATIONS 80dBc 86dBc 89dBc* -130dBc/Hz -152dB FS/Hz -157dB FS/Hz -70dBc -75dBc -85dBc N/S -12dB FS -12dB FS *Measured within a 15MHz window. 14 ______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs MAX5887 FOUR-TONE MULTITONE POWER RATIO PLOT (fCLK = 300MHz, fCENTER = 31.9702MHz) 0 AOUT = -12dB FS BW = 12MHz -10 O INBAND OUTBAND MEASUREMENT BANDWIDTH -30 30kHz 100kHz -60 OUTPUT POWER (dBm) TRANSMITTER EDGE AMPLITUDE (dBc) -20 IMD REQUIREMENT: < -70dBc -70 -73 -75 -80 fT3 fT1 -30 fT4 fT2 -40 -50 -60 -70 -80 -90 WORST-CASE NOISE LEVEL -90 -100 -110 26 0.2 0.4 0.6 1.2 1.8 28 30 6.0 FREQUENCY OFFSET FROM CARRIER (MHz) fT1 = 30.0659MHz fT2 = 31.0181MHz fT3 = 33.0688MHz fT4 = 34.0209MHz 32 34 36 38 fOUT (MHz) Figure 11. GSM/EDGE Tx Mask Requirements Figure 12. Four-Tone MTPR Test Results quency applications should be closely followed. This reduces EMI and internal crosstalk that can significantly affect the dynamic performance of the MAX5887. Use of a multilayer printed circuit (PC) board with separate ground and power-supply planes is recommended. High-speed signals should run on lines directly above the ground plane. Since the MAX5887 has separate analog and digital ground buses (AGND, CLKGND, and DGND, respectively), the PC board should also have separate analog and digital ground sections with only one point connecting the two planes. Digital signals should be run above the digital ground plane and analog/clock signals above the analog/clock ground plane. Digital signals should be kept as far away from sensitive analog inputs, reference inputs sense lines, common-mode input, and clock inputs as practical. A symmetric design of clock input and analog output lines is recommended to minimize 2nd-order harmonic distortion components and optimize the DAC's dynamic performance. Digital signal paths should be kept short and run lengths matched to avoid propagation delay and data skew mismatches. The MAX5887 supports three separate power-supply inputs for analog (AVDD), digital (DVDD), and clock (VCLK) circuitry. Each AVDD, DVDD, and VCLK input should at least be decoupled with a separate 0.1F capacitor as close to the pin as possible and their opposite ends with the shortest possible connection to the corresponding ground plane (Figure 13). Try to minimize the analog and digital load capacitances for optimized operation. All three power-supply voltages should also be decoupled at the point they enter the PC board with tantalum or electrolytic capacitors. Ferrite beads with additional decoupling capacitors forming a pi network could also improve performance. The analog and digital power-supply inputs AVDD , VCLK, and DVDD of the MAX5887 allow a supply voltage range of 3.3V 5%. The MAX5887 is packaged in a 68-pin QFN-EP package (package code: G6800-4), providing greater design flexibility, increased thermal efficiency**, and optimized AC performance of the DAC. The EP enables the user to implement grounding techniques, which are necessary to ensure highest performance operation. The EP must be soldered down to AGND. **Thermal efficiency is not the key factor, since the MAX5887 features low-power operation. The exposed pad is the key element to ensure a solid ground connection between the DAC and the PC board's analog ground layer. ______________________________________________________________________________________ 15 MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs In this package, the data converter die is attached to an EP lead frame with the back of this frame exposed at the package bottom surface, facing the PC board side of the package. This allows a solid attachment of the package to the PC board with standard infrared (IR) flow soldering techniques. A specially created land pattern on the PC board, matching the size of the EP (6mm 6mm), ensures the proper attachment and grounding of the DAC. Designing vias*** into the land area and implementing large ground planes in the PC board design allow for highest performance operation of the DAC. An array of at least 4 4 vias (0.3mm diameter per via hole and 1.2mm pitch between via holes) is recommended for this 68-pin QFN-EP package. Static Performance Parameter Definitions Integral Nonlinearity (INL) Integral nonlinearity is the deviation of the values on an actual transfer function from either a best straight line fit (closest approximation to the actual transfer curve) or a line drawn between the end points of the transfer function, once offset and gain errors have been nullified. For a DAC, the deviations are measured at every individual step. Differential Nonlinearity (DNL) Differential nonlinearity is the difference between an actual step height and the ideal value of 1 LSB. A DNL error specification of less than 1 LSB guarantees no missing codes and a monotonic transfer function. Offset Error The offset error is the difference between the ideal and the actual offset current. For a DAC, the offset point is the average value at the output for the two midscale digital input codes with respect to the full scale of the DAC. This error affects all codes by the same amount. ***Vias connect the land pattern to internal or external copper planes. It is important to connect as many vias as possible to the analog ground plane to minimize inductance. BYPASSING--DAC LEVEL BYPASSING--BOARD LEVEL AVCC AVCC VCLK 0.1F FERRITE BEAD 1F 0.1F AGND 10F 47F ANALOG POWER-SUPPLY SOURCE 47F DIGITAL POWER-SUPPLY SOURCE 47F CLOCK POWER-SUPPLY SOURCE CLKGND DVCC OUTP B0-B13 FERRITE BEAD MAX5887 1F 14 10F OUTN 0.1F VCLK FERRITE BEAD DGND 1F 10F DVDD Figure 13. Recommended Power-Supply Decoupling and Bypassing Circuitry 16 ______________________________________________________________________________________ 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs Settling Time The settling time is the amount of time required from the start of a transition until the DAC output settles its new output value to within the converter's specified accuracy. Glitch Energy A glitch is generated when a DAC switches between two codes. The largest glitch is usually generated around the midscale transition, when the input pattern transitions from 011...111 to 100...000. The glitch energy is found by integrating the voltage of the glitch at the midscale transition over time. The glitch energy is usually specified in pV-s. Dynamic Performance Parameter Definitions Signal-to-Noise Ratio (SNR) For a waveform perfectly reconstructed from digital samples, the theoretical maximum SNR is the ratio of the fullscale analog output (RMS value) to the RMS quantization error (residual error). The ideal, theoretical minimum can be derived from the DAC's resolution (N bits): Two-/Four-Tone Intermodulation Distortion (IMD) The two-tone IMD is the ratio expressed in dBc (or dB FS) of either input tone to the worst 3rd-order (or higher) IMD products. Note that 2nd-order IMD products usually fall at frequencies that can be easily removed by digital filtering; therefore, they are not as critical as 3rd-order IMDs. The two-tone IMD performance of the MAX5887 was tested with the two individual input tone levels set to at least -6dB FS and the four-tone performance was tested according to the GSM model at an output frequency of 32MHz and amplitude of -12dB FS. Adjacent Channel Leakage Power Ratio (ACLR) Commonly used in combination with W-CDMA, ACLR reflects the leakage power ratio in dB between the measured power within a channel relative to its adjacent channel. ACLR provides a quantifiable method of determining out-of-band spectral energy and its influence on an adjacent channel when a bandwidth-limited RF signal passes through a nonlinear device. Chip Information TRANSISTOR COUNT: 10,629 PROCESS: CMOS SNRdB = 6.02dB N + 1.76dB However, noise sources such as thermal noise, reference noise, clock jitter, etc., affect the ideal reading; therefore, SNR is computed by taking the ratio of the RMS signal to the RMS noise, which includes all spectral components minus the fundamental, the first four harmonics, and the DC offset. Spurious-Free Dynamic Range (SFDR) SFDR is the ratio of RMS amplitude of the carrier frequency (maximum signal components) to the RMS value of their next-largest distortion component. SFDR is usually measured in dBc and with respect to the carrier frequency amplitude or in dB FS with respect to the DAC's full-scale range. Depending on its test condition, SFDR is observed within a predefined window or to Nyquist. ______________________________________________________________________________________ 17 MAX5887 Gain Error A gain error is the difference between the ideal and the actual full-scale output voltage on the transfer curve, after nullifying the offset error. This error alters the slope of the transfer function and corresponds to the same percentage error in each step. Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) 68L QFN.EPS MAX5887 3.3V, 14-Bit, 500Msps High Dynamic Performance DAC with Differential LVDS Inputs PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM 1 C 21-0122 2 * PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM 1 C 21-0122 2 MAX5887 Package Code: G6800-4 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.