View MAX5885_575754.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-2786; Rev 1; 12/03
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
General Description
The MAX5885 is an advanced, 16-bit, 200Msps 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 77dBc spurious-free dynamic range (SFDR) at f OUT = 10MHz. The DAC supports update rates of 200Msps at a power dissipation of less than 200mW. The MAX5885 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 MAX5885 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. The digital and clock inputs of the MAX5885 are designed for CMOS-compatible voltage levels. The MAX5885 is available in a 48-pin QFN package with an exposed paddle (EP) and is specified for the extended industrial temperature range (-40C to +85C). Refer to the MAX5883 and MAX5884 data sheets for pin-compatible 12- and 14-bit versions of the MAX5885. For LVDS high-speed versions, refer to the MAX5886/ MAX5887/MAX5888 data sheet. 200Msps Output Update Rate Single 3.3V Supply Operation Excellent SFDR and IMD Performance SFDR = 77dBc at fOUT = 10MHz (to Nyquist) IMD = -88dBc at fOUT = 10MHz ACLR = 74dB at fOUT = 30.72MHz 2mA to 20mA Full-Scale Output Current CMOS-Compatible Digital and Clock Inputs On-Chip 1.2V Bandgap Reference Low Power Dissipation 48-Pin QFN-EP Package
Features
MAX5885
Ordering Information
PART MAX5885EGM TEMP RANGE -40C to +85C PIN-PACKAGE 48 QFN-EP*
*EP = Exposed paddle.
Pin Configuration
B5 B6 DVDD B9 B10
39 38
48
47
46
B3 B4
45
44
43
42
41
40
Applications
Base Stations: Single/Multicarrier UMTS, CDMA, GSM Communications: LMDS, MMDS, Point-to-Point Microwave Digital Signal Synthesis Automated Test Equipment (ATE) Instrumentation
B1 B0 XOR VCLK CLKGND CLKP CLKN CLKGND VCLK PD AVDD AGND
1 2 3 4 5 6 7 8 9 10 11 12
37 36 35 34 33 32 31 30 29 28 27 26 25
B11
TOP VIEW B2
DGND B7 B8
B12 B13 B14 B15 DGND DVDD SEL0 N.C. N.C. N.C. N.C. N.C.
MAX5885
13
14
15
16
17
18
19
20
21
22
23
FSADJ DACREF N.C.
________________________________________________________________ Maxim Integrated Products
AGND IOUTN IOUTP
QFN
AGND AVDD AGND AVDD AGND
REFIO
24
1
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.
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
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 B0-B15, SEL0, PD, XOR to DGND.............-0.3V to DVDD + 0.3V Continuous Power Dissipation (TA = +70C) 48-Pin QFN (derate 27mW/C above +70C)............2162.2mW Thermal Resistance (JA) ..............................................+37C/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 = 0V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, fCLK = 200Msps, 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 STATIC PERFORMANCE Resolution Integral Nonlinearity Differential Nonlinearity Offset Error Offset Drift Full-Scale Gain Error Gain Drift Full-Scale Output Current Min Output Voltage Max Output Voltage Output Resistance Output Capacitance DYNAMIC PERFORMANCE Output Update Rate Noise Spectral Density Spurious-Free Dynamic Range to Nyquist fCLK fCLK = 100MHz fCLK = 200MHz SFDR fCLK = 100MHz fOUT = 16MHz, -12dB FS fOUT = 80MHz, -12dB FS fOUT = 1MHz, 0dB FS fOUT = 1MHz, -6dB FS fOUT = 1MHz, -12dB FS 1 -155 -148 88 83 80 dBc 200 Msps dB FS/ Hz ROUT COUT IOUT GEFS External reference, TA +25C Internal reference External reference (Note 1) Single ended Single ended 2 -0.5 1.1 1 5 -3.5 100 50 20 INL DNL OS Measured differentially Measured differentially -0.025 16 0.006 0.003 0.003 50 +1.3 +0.025 Bits %FS %FS %FS ppm/C %FS ppm/C mA V V M pF SYMBOL CONDITIONS MIN TYP MAX UNITS
2
_______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
ELECTRICAL CHARACTERISTICS (continued)
(AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, fCLK = 200Msps, 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 fOUT = 10MHz, -12dB FS fOUT = 30MHz, -12dB FS fOUT = 10MHz, -12dB FS SFDR fCLK = 200MHz fOUT = 16MHz, -12dB FS, TA +25C fOUT = 30MHz, -12dB FS fOUT = 50MHz, -12dB FS fCLK = 100MHz Two-Tone IMD TTIMD fCLK = 200MHz Four-Tone IMD, 1MHz Frequency Spacing, GSM Model Adjacent Channel Leakage Power Ratio, 4.1MHz Bandwidth, WCDMA Model Output Bandwidth REFERENCE Internal Reference Voltage Range Reference Input Compliance Range Reference Input Resistance Reference Voltage Drift ANALOG OUTPUT TIMING Output Fall Time Output Rise Time Output Voltage Settling Time Output Propagation Delay Glitch Energy Output Noise TIMING CHARACTERISTICS Data to Clock Setup Time Data to Clock Hold Time tSETUP tHOLD Referenced to rising edge of clock (Note 4) Referenced to rising edge of clock (Note 4) 0.4 1.25 ns ns NOUT IOUT = 2mA IOUT = 20mA tFALL tRISE tSETTLE tPD 90% to 10% (Note 3) 10% to 90% (Note 3) Output settles to 0.025% FS (Note 3) (Note 3) 375 375 11 1.8 1 30 30 ps ps ns ns pV-s pA/Hz VREFIO VREFIOCR RREFIO TCOREF 1.1 0.125 10 50 1.21 1.34 1.25 V V k ppm/C FTIMD fCLK = 150MHz fCLK = 184.32MHz (Note 2) fOUT1 = 9MHz, -6dB FS fOUT2 = 10MHz, -6dB FS fOUT1 = 29MHz, -6dB FS fOUT2 = 30MHz, -6dB FS fOUT = 31.99MHz, -12dB FS fOUT = 30.72MHz 68 MIN TYP 77 73 72 76 71 71 -88 dBc -74 -82 dBc dBc MAX UNITS
MAX5885
ACLR BW-1dB
74 450
dB MHz
_______________________________________________________________________________________
3
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
ELECTRICAL CHARACTERISTICS (continued)
(AVDD = DVDD = VCLK = 3.3V, AGND = DGND = CLKGND = 0V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, fCLK = 200Msps, 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 Data Latency Minimum Clock Pulse Width High tCH CLKP, CLKN Minimum Clock Pulse Width Low tCL CLKP, CLKN CMOS LOGIC INPUTS (B0-B15, PD, SEL0, XOR) Input Logic High Input Logic Low Input Leakage Current Input Capacitance CLOCK INPUTS (CLKP, CLKN) Differential Input Voltage Swing Differential Input Slew Rate Common-Mode Voltage Range Input Resistance Input Capacitance POWER SUPPLIES Analog Supply Voltage Range Digital Supply Voltage Range Clock Supply Voltage Range Analog Supply Current Digital Supply Current Clock Supply Current Power Dissipation Power-Supply Rejection Ratio AVDD DVDD VCLK IAVDD IDVDD IVCLK PDISS PSRR fCLK = 100Msps, fOUT = 1MHz Power-down fCLK = 100Msps, fOUT = 1MHz Power-down fCLK = 100Msps, fOUT = 1MHz Power-down fCLK = 100Msps, fOUT = 1MHz Power-down AVDD = VCLK = DVDD = 3.3V 5% (Note 5) -0.1 3.135 3.135 3.135 3.3 3.3 3.3 27 0.3 8.5 10 5.5 10 135 1 +0.1 3.465 3.465 3.465 V V V mA mA A mA A mW %FS/V VCLK SRCLK VCOM RCLK CCLK Sine wave Square wave (Note 5) 1.5 0.5 >100 1.5 20% 5 5 VP-P V/s V k pF VIH VIL IIN CIN -15 5 0.7 x DVDD 0.3 x DVDD +15 SYMBOL CONDITIONS MIN TYP 3.5 1.5 1.5 MAX UNITS Clock cycles ns ns
V V A pF
Note 1: Note 2: Note 3: Note 4: Note 5:
Nominal full-scale current IOUT = 32 IREF. This parameter does not include update-rate depending effects of sin(x)/x filtering inherent in the MAX5885. Parameter measured single ended into a 50 termination resistor. Parameter guaranteed by design. Parameter defined as the change in midscale output caused by a 5% variation in the nominal supply voltage.
4
_______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
Typical Operating Characteristics
(AVDD = DVDD = VCLK = 3.3V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, TA = +25C, unless otherwise noted.)
SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 50MHz)
90 80 70 SFDR (dBc) SFDR (dBc) 60 50 40 30 20 10 0 0 5 10 15 20 25 fOUT (MHz) -6dB FS 0dB FS -12dB FS
MAX5885 toc01
SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 100MHz)
MAX5885 toc02
SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 150MHz)
90 80 70 SFDR (dBc) 60 50 40 30 20 10 0 -6dB FS 0dB FS -12dB FS
MAX5885 toc03
100
100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 0dB FS -12dB FS -6dB FS
100
50
0
15
30
45
60
75
fOUT (MHz)
fOUT (MHz)
SPURIOUS-FREE DYNAMIC RANGE vs. OUTPUT FREQUENCY (fCLK = 200MHz)
MAX5885 toc04
TWO-TONE IMD vs. OUTPUT FREQUENCY (1MHz CARRIER SPACING, fCLK = 100MHz)
MAX5885 toc05
TWO-TONE INTERMODULATION DISTORTION (fCLK = 100MHz)
-10 -20 OUTPUT POWER (dBm) -30 -40 -50 -60 -70 -80 -90 2 x fT1 - fT2 2 x fT2 - fT1 fT1 fT2 AOUT = -6dB FS BW = 12MHz fT1 = 28.9429MHz fT2 = 29.8706MHz
MAX5885 toc06 MAX5885 toc09
100 90 80 70 SFDR (dBc) 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 fOUT (MHz) -6dB FS 0dB FS -12dB FS
-100 -90 TWO-TONE IMD (dBc) -80 -70 -6dB FS -60 -50 -40 -12dB FS
0
-100 0 10 20 30 40 50 24 25 26 27 28 29 30 31 32 33 34 35 36 fOUT (MHz) fOUT (MHz)
90 100
TWO-TONE IMD vs. OUTPUT FREQUENCY (1MHz CARRIER SPACING, fCLK = 200MHz)
MAX5885 toc07
SFDR vs. OUTPUT FREQUENCY (fCLK = 200MHz, AOUT = -6dB FS)
MAX5885 toc08
SFDR vs. fOUT AND TEMPERATURE (fCLK = 200MHz, AOUT = -6dB FS, IFS = 20mA)
100 90 80 70 SFDR (dBc) TA = -40C
-100 -90 TWO-TONE IMD (dBc) -12dB FS -80
100 IOUT = 20mA 80
SFDR (dBc)
60 IOUT = 5mA 40 IOUT = 10mA
60 50 40 30 TA = +85C
-70 -60 -50 -40 0 10 20 30 40 50 60 70 80 fOUT (MHz) -6dB FS
TA = +25C
20
20 10
0 0 10 20 30 40 50 60 70 80 90 100 fOUT (MHz)
0 0 10 20 30 40 50 60 70 80 90 100 fOUT (MHz)
_______________________________________________________________________________________
5
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
Typical Operating Characteristics (continued)
(AVDD = DVDD = VCLK = 3.3V, external reference, VREFIO = 1.25V, RL = 50, IOUT = 20mA, TA = +25C, unless otherwise noted.)
INTEGRAL NONLINEARITY vs. DIGITAL INPUT CODE
MAX5885 toc10
DIFFERENTIAL NONLINEARTIY vs. DIGITAL INPUT CODE
MAX5885 toc11
POWER DISSIPATION vs. CLOCK FREQUENCY (fOUT = 10MHz, AOUT = 0dB FS, IOUT = 20mA)
MAX5885 toc12
4 3 2
3 2 1 DNL (LSB) 0 -1 -2 -3
190 170 POWER DISSIPATION (mW)
1 INL (LSB) 0 -1 -2 -3 -4 0 10000 20000 30000 40000 50000 60000 70000 DIGITAL INPUT CODE
150
130
110
90 0 10000 20000 30000 40000 50000 60000 70000 DIGITAL INPUT CODE 25 50 75 100 125 150 175 200 fCLK (MHz)
POWER DISSIPATION vs. SUPPLY VOLTAGE (fCLK = 100MHz, fOUT = 10MHz, IFS = 20mA)
MAX5885 toc13
170
POWER DISSIPATION (mW)
162 EXTERNAL REFERENCE 154
146 INTERNAL REFERENCE 138
130 3.135 3.190
3.245 3.300
3.355 3.410
3.465
SUPPLY VOLTAGE (V)
6
_______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
Pin Description
PIN 1 2 NAME B1 B0 Data Bit 1 Data Bit 0 (LSB) XOR Input Pin. XOR = 1 inverts the digital input data. XOR = 0 leaves the digital input data unchanged. XOR has an internal pulldown resistor and may be left unconnected if not used. 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. Clock Ground Converter Clock Input. Positive input terminal for the converter clock. Complementary Converter Clock Input. Negative input terminal for the converter clock. Power-Down Input. PD pulled high enables the DAC's power-down mode. PD pulled low allows for normal operation of the DAC. 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. Analog Ground. Exposed paddle (EP) must be connected to AGND. Reference I/O. Output of the internal 1.2V precision bandgap reference. Bypass with a 0.1F capacitor to AGND. Can be driven with an external reference source. 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. Return Path for the Current Set Resistor. For 20mA full-scale output current, connect a 2k resistor between FSADJ and DACREF. No connection. Do not connect to these pins. Do not tie these pins together. Complementary DAC Output. Negative terminal for differential current output. The full-scale output current range can be set from 2mA to 20mA. DAC Output. Positive terminal for differential current output. The full-scale output current range can be set from 2mA to 20mA. Mode Select Input SEL0. This pin has an internal pulldown resistor; it can be left open to disable the segment-shuffling function (see the Segment Shuffling section). 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. Digital Ground Data Bit 15 (MSB) Data Bit 14 Data Bit 13 Data Bit 12 Data Bit 11 FUNCTION
MAX5885
3
XOR
4, 9 5, 8 6 7 10 11, 21, 23 12, 17, 20, 22, 24, EP 13 14 15 16, 25, 26, 27, 28, 29 18 19 30 31, 43 32, 42 33 34 35 36 37
VCLK CLKGND CLKP CLKN PD AVDD AGND REFIO FSADJ DACREF N.C. IOUTN IOUTP SEL0 DVDD DGND B15 B14 B13 B12 B11
_______________________________________________________________________________________
7
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
Pin Description (continued)
PIN 38 39 40 41 44 45 46 47 48 NAME B10 B9 B8 B7 B6 B5 B4 B3 B2 Data Bit 10 Data Bit 9 Data Bit 8 Data Bit 7 Data Bit 6 Data Bit 5 Data Bit 4 Data Bit 3 Data Bit 2 FUNCTION
DVDD
DGND
SEL0
PD
1.2V REFERENCE
FUNCTION SELECTION BLOCK
AGND AVDD
MAX5885
REFIO CURRENT-STEERING DAC IOUTP IOUTN
FSADJ
CLKN CLKP
SEGMENT SHUFFLING/LATCH
DECODER
CMOS RECEIVER/INPUT LATCH
16 DIGITAL INPUTS B0 THROUGH B15
Figure 1. Simplified MAX5885 Block Diagram 8 _______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
Detailed Description
Architecture
The MAX5885 is a high-performance, 16-bit, currentsteering DAC (Figure 1) capable of operating with clock speeds up to 200MHz. The converter consists of separate input and DAC registers, followed by a current-steering 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. 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.
MAX5885
Analog Outputs (IOUTP, IOUTN)
The MAX5885 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 converted 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.
Reference Architecture and Operation
The MAX5885 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 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 MAX5885'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 - 1 LSB IOUT = 32 IREFIO - (IOUT / 216) 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,
AVDD
1.2V REFERENCE
10k REFIO 0.1F
FSADJ IREF RSET DACREF IREF = VREFIO/RSET CURRENT-STEERING DAC
IOUTP
IOUTN
Figure 2. Reference Architecture, Internal Reference Configuration
Table 1. IOUT and RSET Selection Matrix Based on a Typical 1.200V Reference Voltage
FULL-SCALE CURRENT IOUT (mA) 2 5 10 15 20 REFERENCE CURRENT IREF (A) 62.5 156.26 312.5 468.75 625 RSET (k) CALCULATED 19.2 7.68 3.84 2.56 1.92 1% EIA STD 19.1 7.5 3.83 2.55 1.91 OUTPUT VOLTAGE VIOUTP/N* (mVP-P) 100 250 500 750 1000
*Terminated into a 50 load. _______________________________________________________________________________________ 9
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
Although not recommended because of additional noise pickup from the ground plane, for single-ended operation 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 MAX5885's internal output structure.
Data Timing Relationship
Figure 5 shows the timing relationship between differential, digital CMOS data, clock, and output signals. The MAX5885 features a 1.25ns hold, a 0.4ns setup, and a 1.8ns propagation delay time. There is a 3.5 clock-cycle latency between CLKP/CLKN transitioning high/low and IOUTP/IOUTN.
CMOS-Compatible Digital Inputs (B0-B15)
The MAX5885 features single-ended, CMOS-compatible receivers on the bus input interface. These CMOS inputs (B0-B15) allow for a voltage swing of 3.3V. Segment Shuffling (SEL0) Segment shuffling can improve the SFDR of the MAX5885 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 MAX5885 segment-shuffling function, SEL0 must be pulled high. XOR Function (XOR) The MAX5885 is equipped with a single-ended, CMOScompatible XOR input, which may be left open (XOR provides an internal pulldown resistor) or pulled down to DGND, if not used. Input data is XORed with the bit applied to the XOR pin. Pulling XOR high inverts the input data. Pulling XOR low leaves the input data noninverted. By applying a pseudorandom bit stream to XOR and applying data while XOR is high, the bit transitions in the digital input data can be decorrelated from the DAC output, allowing the user to troubleshoot possible spurious or harmonic distortion degradation due to digital feedthrough on the PC board.
WIDEBAND RF TRANSFORMER PERFORMS SINGLE-ENDED TO DIFFERENTIAL CONVERSION. 0.1F CLKP 25
Clock Inputs (CLKP, CLKN)
The MAX5885 features a flexible differential clock input (CLKP, CLKN) operating from separate supplies (VCLK, CLKGND) to achieve the best 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 VCLK/2. 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 a CMOS-compatible clock source; however, it is recommended to use sinewave or AC-coupled ECL drive for best performance.
AVDD CURRENT SOURCES CURRENT SWITCHES
1:1 SINGLE-ENDED CLOCK SOURCE (e.g., HP 8662A) 25
TO DAC
0.1F
IOUT IOUTN IOUT IOUTP
CLKN
CLKGND
Figure 3. Simplified Analog Output Structure 10
Figure 4. Differential Clock Signal Generation
______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
DIGITAL DATA IS LATCHED ON THE RISING EDGE OF CLKP OUTPUT DATA IS UPDATED ON THE FALLING EDGE OF CLKP
B0 TO B15
N-1
N
N+1
N+2
tSETUP
tHOLD
tCH
tCL
CLKP
CLKN tPD
IOUT
N-5
N-4
N-3
N-2
N-1
Figure 5. Detailed Timing Relationship
Power-Down Operation (PD) The MAX5885 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 this 16-bit CMOS DAC allows the overall power consumption to be reduced to less than 1mW. The MAX5885 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 6) 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 MAX5885. 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 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 7).
If a single-ended unipolar output is desirable, IOUTP should be selected as the output, with IOUTN grounded. However, driving the MAX5885 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 MAX5885 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.
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-CDMAmodulated carrier.
______________________________________________________________________________________
11
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
AVDD DVDD VCLK 50 T2, 1:1 B0-B15 IOUTP VOUT, SINGLE ENDED
MAX5885
16 IOUTN
100
T1, 1:1 AGND DGND CLKGND 50 WIDEBAND RF TRANSFORMER T2 PERFORMS THE DIFFERENTIAL TO SINGLE-ENDED CONVERSION.
Figure 6. Differential to Single-Ended Conversion Using a Wideband RF Transformer
AVDD
DVDD
VCLK 50 OUTP 100 IOUTN OUTN 50
B0-B15
IOUTP
MAX5885
16
AGND
DGND
CLKGND
Figure 7. MAX5885 Differential Output Configuration
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 single-carrier W-CDMA modulation, these IMD products are spread 3.84MHz over the adjacent sideband. Four contiguous 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 sideband 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 8 shows the ACLR performance for a single W-CDMA carrier (fCLK = 184.32MHz, fOUT = 30.72MHz) applied to the MAX5885 (including measurement system limitations*). Figure 9 illustrates the ACLR test results for the MAX5885 with a four-carrier W-CDMA signal at an output frequency of 30.72MHz and a sampling frequency of 184.32MHz. Considerable care must be taken to ensure accurate measurement of this parameter.
*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. 12 ______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
Multitone Testing for GSM/EDGE Applications
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. 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 10 support per-carrier output power levels of 20W or greater. Lower output power levels yield less-stringent emission requirements.
-20 -30 ANALOG OUTPUT POWER (dBm) -40 -50 -60 -70 -80 -90 -100 -110 -120 3.5MHz/div fCLK = 184.32MHz fCENTER = 30.72MHz ACLR = 74dB
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 sinewave, 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. 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.
MAX5885
Figure 8. ACLR for W-CDMA Modulation, Single Carrier
ANALOG OUTPUT POWER (dBm)
-40 -50 -60 -70 -80 -90 -100 -110 -120 -125
AMPLITUDE (dBc)
-30
MEASUREMENT BANDWIDTH 30kHz 100kHz
-60 -70 -73 -75 -80 -90 0.2 0.4 0.6 1.2 1.8
IMD REQUIREMENT: < -70dBc WORST-CASE NOISE LEVEL
6.0
3.5MHz/div
FREQUENCY OFFSET FROM CARRIER (MHz)
Figure 9. ACLR for W-CDMA Modulation, Four Carriers
Figure 10. GSM/EDGE Tx Mask Requirements 13
______________________________________________________________________________________
TRANSMITTER EDGE
-25 -30
O
INBAND
OUTBAND
fCLK = 184.32MHz, fCENTER = 30.72MHz ACLR = 67dB
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
Table 2. GSM/EDGE Noise Requirements for Multicarrier Systems
NUMBER OF CARRIERS 2 4 CARRIER POWER LEVEL (dB FS) -6 -12 DAC NOISE DENSITY REQUIREMENT (dB FS/Hz) -146 -152
The four-tone MTPR plot in Figure 11 demonstrates the MAX5885's excellent dynamic performance. The center frequency (fCENTER = 31.99MHz) 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 -82dBc.
MAX5885
Another key factor 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 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.
Grounding, Bypassing, and Power-Supply Considerations
Grounding and power-supply decoupling can strongly influence the performance of the MAX5885. 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-frequency applications should be closely followed. This reduces EMI and internal crosstalk that can significantly affect the dynamic performance of the MAX5885. 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 MAX5885 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 input 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
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 80dBc -130dBc/Hz -70dBc N/S DAC REQUIREMENTS WITH MARGINS 86dBc -152dB FS/Hz -75dBc -12dB FS MAX5885 SPECIFICATIONS 85dBc* -155dB FS/Hz -79dBc -12dB FS
*Measured within a 15MHz window.
14
______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
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 MAX5885 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 12). 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 MAX5885 allow a supply voltage range of 3.3V 5%. The MAX5885 is packaged in a 48-pin QFN-EP (package code: G4877-1), 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. 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 (5mm 5mm), 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 3 3 vias (0.3mm diameter per via hole and 1.2mm pitch between via holes) is recommended for this 48-pin QFN-EP package.
MAX5885
FOUR-TONE MULTITONE POWER RATIO PLOT (fCLK = 150MHz, fCENTER = 31.9885MHz)
0 -10 -20 OUTPUT POWER (dBm) -30 -40 -50 -60 -70 -80 -90 -100 26 28 30 32 fOUT (MHz) fT1 = 29.9744MHz fT2 = 30.9998MHz fT3 = 32.9773MHz fT4 = 33.8196MHz 34 36 38 AOUT = -12dB FS fT1 fT2 fT3 fT4
Figure 11. 4-Tone MTPR Test Results
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 point. For a DAC, the offset point is the step value when the digital input is at midscale. This error affects all codes by the same amount.
**Thermal efficiency is not the key factor, since the MAX5885 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. ***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.
______________________________________________________________________________________
15
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
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. 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 maximum SNR can be derived from the DAC's resolution (N bits): 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.
BYPASSING--DAC LEVEL AVCC AVDD VCLK
BYPASSING--BOARD LEVEL
FERRITE BEAD ANALOG POWER-SUPPLY SOURCE
0.1F
0.1F
1F
10F
47F
AGND
CLKGND OUTP DVCC FERRITE BEAD
B0-B15
MAX5885
16 1F OUTN 10F 47F
DIGITAL POWER-SUPPLY SOURCE
0.1F
VCLK FERRITE BEAD
DGND 1F DVDD 10F 47F CLOCK POWER-SUPPLY SOURCE
Figure 12. Recommended Power-Supply Decoupling and Bypassing Circuitry
16
______________________________________________________________________________________
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs
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.
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.
MAX5885
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 MAX5885 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.
Chip Information
TRANSISTOR COUNT: 10,721 PROCESS: CMOS
______________________________________________________________________________________
17
3.3V, 16-Bit, 200Msps High Dynamic Performance DAC with CMOS Inputs MAX5885
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.)
32, 44, 48L QFN.EPS
PACKAGE OUTLINE 32,44,48L QFN, 7x7x0.90 MM
21-0092
H
1
2
U
PACKAGE OUTLINE, 32,44,48L QFN, 7x7x0.90 MM
21-0092
H
2
2
MAX5885 Package Code: G4877-1
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.

▲Up To Search▲

Price & Availability of MAX5885

	To Download MAX5885 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .