19-4312; Rev 0; 10/08 Dual-Channel, 8-Bit, 100Msps ADC The MAX19506 dual-channel, analog-to-digital converter (ADC) provides 8-bit resolution and a maximum sample rate of 100Msps. The MAX19506 analog input accepts a wide 0.4V to 1.4V input common-mode voltage range, allowing DCcoupled inputs for a wide range of RF, IF, and baseband front-end components. The MAX19506 provides excellent dynamic performance from baseband to high input frequencies beyond 400MHz, making the device ideal for zero-intermediate frequency (ZIF) and highintermediate frequency (IF) sampling applications. The typical signal-to-noise ratio (SNR) performance is 49.8dBFS and typical spurious-free dynamic range (SFDR) is 69dBc at fIN = 70MHz and fCLK = 100MHz. The MAX19506 operates from a 1.8V supply. Additionally, an integrated, self-sensing voltage regulator allows operation from a 2.5V to 3.3V supply (AVDD). The digital output drivers operate on an independent supply voltage (OVDD) over the 1.8V to 3.5V range. The analog power consumption is only 57mW per channel at V AVDD = 1.8V. In addition to low operating power, the MAX19506 consumes only 1mW in powerdown mode and 17mW in standby mode. Various adjustments and feature selections are available through programmable registers that are accessed through the 3-wire serial-port interface. Alternatively, the serial-port interface can be disabled, with the three pins available to select output mode, data format, and clock-divider mode. Data outputs are available through a dual parallel CMOS-compatible output data bus that can also be configured as a single multiplexed parallel CMOS bus. The MAX19506 is available in a small 7mm x 7mm, 48pin thin QFN package and is specified over the -40°C to +85°C extended temperature range. Refer to the MAX19515, MAX19516, and MAX19517 data sheets for pin- and feature-compatible 10-bit, 65Msps, 100Msps, and 130Msps versions, respectively. Refer to the MAX19505 and MAX19507 data sheets for pin- and feature-compatible 8-bit, 65Msps and 130Msps versions, respectively. Applications IF and Baseband Communications, Including Cellular Base Stations and Point-to-Point Microwave Receivers Ultrasound and Medical Imaging Portable Instrumentation and Low-Power Data Acquisition Digital Set-Top Boxes Features o Very-Low-Power Operation (57mW/Channel at 100Msps) o 1.8V or 2.5V to 3.3V Analog Supply o Excellent Dynamic Performance 49.8dBFS SNR at 70MHz 69dBc SFDR at 70MHz o User-Programmable Adjustments and Feature Selection through an SPI™ Interface o Selectable Data Bus (Dual CMOS or Single Multiplexed CMOS) o DCLK Output and Programmable Data Output Timing Simplifies High-Speed Digital Interface o Very Wide Input Common-Mode Voltage Range (0.4V to 1.4V) o Very High Analog Input Bandwidth (> 850MHz) o Single-Ended or Differential Analog Inputs o Single-Ended or Differential Clock Input o Divide-by-One (DIV1), Divide-by-Two (DIV2), and Divide-by-Four (DIV4) Clock Modes o Two’s Complement, Gray Code, and Offset Binary Output Data Format o Out-of-Range Indicator (DOR) o CMOS Output Internal Termination Options (Programmable) o Reversible Bit Order (Programmable) o Data Output Test Patterns o Small 7mm x 7mm, 48-Pin Thin QFN Package with Exposed Pad Ordering Information PART TEMP RANGE PIN-PACKAGE MAX19506ETM+ -40°C to +85°C 48 TQFN-EP* +Denotes a lead-free/RoHS-compliant package. *EP = Exposed pad. Pin Configuration appears at end of data sheet. SPI is a trademark of Motorola, Inc. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX19506 General Description MAX19506 Dual-Channel, 8-Bit, 100Msps ADC ABSOLUTE MAXIMUM RATINGS OVDD, AVDD to GND............................................-0.3V to +3.6V CMA, CMB, REFIO, INA+, INA-, INB+, INB- to GND ......................................................-0.3V to +2.1V CLK+, CLK-, SYNC, SPEN, CS, SCLK, SDIN to GND ..........-0.3V to the lower of (VAVDD + 0.3V) and +3.6V DCLKA, DCLKB, D7A–D0A, D7B–D0B, DORA, DORB to GND..........-0.3V to the lower of (VOVDD + 0.3V) and +3.6V Continuous Power Dissipation (TA = +70°C) 48-Pin Thin QFN, 7mm x 7mm x 0.8mm (derate 40mW/°C above +70°C).............................................................3200mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC ACCURACY Resolution 8 Bits Integral Nonlinearity INL fIN = 3MHz -0.3 ±0.1 +0.3 Differential Nonlinearity DNL fIN = 3MHz -0.3 ±0.1 +0.3 LSB LSB Offset Error OE Internal reference -0.4 ±0.1 +0.4 %FS Gain Error GE External reference = 1.25V -1.5 ±0.3 +1.5 %FS ANALOG INPUTS (INA+, INA-, INB+, INB-) (Figure 3) Differential Input-Voltage Range VDIFF Differential or single-ended inputs Common-Mode Input-Voltage Range VCM (Note 2) Input Resistance Input Current Input Capacitance RIN IIN CPAR CSAMPLE 1.5 0.4 Fixed resistance, common mode, and differential mode VP-P 1.4 V > 100 kΩ Differential input resistance, common mode connected to inputs 4 Switched capacitance common-mode input current, each input 54 Fixed capacitance to ground, each input 0.7 Switched capacitance, each input 1.2 µA pF CONVERSION RATE Maximum Clock Frequency fCLK Minimum Clock Frequency fCLK Data Latency 2 100 MHz 50 Figures 9, 10 9 _______________________________________________________________________________________ MHz Cycles Dual-Channel, 8-Bit, 100Msps ADC (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC PERFORMANCE Small-Signal Noise Floor SSNF Signal-to-Noise Ratio SNR fIN = 70MHz, < -35dBFS -49.8 fIN = 3MHz Signal-to-Noise Plus Distortion Ratio SINAD fIN = 70MHz 49.8 49.0 49.8 fIN = 3MHz 49.3 48.5 fIN = 175MHz Spurious-Free Dynamic Range (4th and Higher Harmonics) Second Harmonic SFDR1 SFDR2 HD2 Third Harmonic HD3 Total Harmonic Distortion Third-Order Intermodulation Full-Power Bandwidth THD IM3 FPBW fIN = 70MHz 77.0 65.0 77.0 fIN = 175MHz 77.0 fIN = 3MHz 69.0 fIN = 70MHz dB 49.3 49.3 fIN = 3MHz Spurious-Free Dynamic Range (2nd and 3rd Harmonic) dBFS 49.8 fIN = 175MHz fIN = 70MHz dBFS 64.0 dBc dBc 69.0 fIN = 175MHz 69.0 fIN = 3MHz -78.0 fIN = 70MHz -78.0 fIN = 175MHz -78.0 fIN = 3MHz -82.0 fIN = 70MHz -82.0 fIN = 175MHz -80.0 fIN = 3MHz -72.0 fIN = 70MHz -72.0 fIN = 175MHz -72.0 fIN = 70MHz ± 1.5MHz, -7dBFS -80 fIN = 175MHz ± 2.5MHz, -7dBFS -75 RSOURCE = 50Ω differential, -3dB rolloff 850 -65.0 dBc -65.0 dBc -63.0 dBc dBc MHz Aperture Delay tAD 850 ps Aperture Jitter tAJ 0.3 psRMS 1 Cycles Overdrive Recovery Time ±10% beyond full scale _______________________________________________________________________________________ 3 MAX19506 ELECTRICAL CHARACTERISTICS (continued) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC ELECTRICAL CHARACTERISTICS (continued) (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS INTERCHANNEL CHARACTERISTICS Crosstalk Gain Match fINA or fINB = 70MHz at -1dBFS 95 fINA or fINB = 175MHz at -1dBFS 85 dBc fIN = 70MHz ±0.05 dB Offset Match fIN = 70MHz ±0.1 %FSR Phase Match fIN = 70MHz ±0.5 Degrees ANALOG OUTPUTS (CMA, CMB) CMA, CMB Output Voltage VCOM Default programmable setting 0.85 0.9 0.95 V 1.23 1.25 1.27 V INTERNAL REFERENCE REFIO Output Voltage REFIO Temperature Coefficient VREFOUT TCREF < ±60 ppm/°C REFIO Input-Voltage Range VREFIN 1.25 +5/-10% V REFIO Input Resistance RREFIN 10 ±20% kΩ 0.4 to 2.0 VP-P EXTERNAL REFERENCE CLOCK INPUTS (CLK+, CLK-)—DIFFERENTIAL MODE Differential Clock Input Voltage Self-biased Differential Input Common-Mode Voltage 1.20 DC-coupled clock signal Input Resistance RCLK Input Capacitance CCLK V 1.0 to 1.4 Differential, default 10 kΩ Differential, programmable internal termination selected 100 Ω Common mode 9 kΩ To ground, each input 3 pF CLOCK INPUTS (CLK+, CLK-)—SINGLE-ENDED MODE (VCLK- < 0.1V) Single-Ended Mode Selection Threshold (VCLK-) 0.1 Allowable Logic Swing (VCLK+) 0 - VAVDD Single-Ended Clock Input High Threshold (VCLK+) Input Leakage (CLK-) Input Capacitance (CLK+) 4 V 1.5 V Single-Ended Clock Input Low Threshold (VCLK+) Input Leakage (CLK+) 0.3 VCLK+ = VAVDD = 1.8V or 3.3V +0.5 VCLK+ = 0 -0.5 VCLK- = 0 -150 V -50 3 _______________________________________________________________________________________ V µA µA pF Dual-Channel, 8-Bit, 100Msps ADC (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS CLOCK INPUTS (SYNC) Allowable Logic Swing 0 - VAVDD Sync Clock Input High Threshold V 1.5 V Sync Clock Input Low Threshold 0.3 VSYNC = VAVDD = 1.8V or 3.3V Input Leakage VSYNC = 0 +0.5 -0.5 Input Capacitance V µA 4.5 pF 0 - VAVDD V DIGITAL INPUTS (SHDN, SPEN) Allowable Logic Swing Input High Threshold 1.5 V Input Low Threshold 0.3 VSHDN/VSPEN = VAVDD = 1.8V or 3.3V Input Leakage VSHDN/VSPEN = 0 Input Capacitance +0.5 -0.5 CDIN V µA 3 pF 0 - VAVDD V SERIAL-PORT INPUTS (SCLK, SDIN, CS, where SPEN = 0V)—SERIAL-PORT CONTROL MODE Allowable Logic Swing Input High Threshold 1.5 V Input Low Threshold 0.3 VSCLK/VSDIN/VCS = VAVDD = 1.8V or 3.3V Input Leakage VSCLK/VSDIN/VCS = 0 Input Capacitance +0.5 -0.5 CDIN 3 V µA pF SERIAL-PORT INPUTS (SCLK, SDIN, CS, where SPEN = VAVDD)—PARALLEL CONTROL MODE (Figure 5) Input Pullup Current Input Pulldown Current Open-Circuit Voltage VOC VSCLK/VSDIN/VCS = VAVDD = 1.8V 7 12 17 VSCLK/VSDIN/VCS = VAVDD = 3.3V 16 21 26 VSCLK/VSDIN/VCS = 0, VAVDD = 1.8V -65 -50 -35 VSCLK/VSDIN/VCS = 0, VAVDD = 3.3V -105 -90 -75 I = 0V, VAVDD = 1.8V 1.35 1.45 1.55 I = 0V, VAVDD = 3.3V 2.58 2.68 2.78 µA µA V DIGITAL OUTPUTS (CMOS MODE, 75Ω, D0–D7 (A and B Channel), DCLKA, DCLKB, DORA, DORB) Output-Voltage Low VOL Output-Voltage High VOH Three-State Leakage Current ILEAK ISINK = 200µA ISOURCE = 200µA 0.2 VOVDD - 0.2 VOVDD applied GND applied V +0.5 -0.5 V µA _______________________________________________________________________________________ 5 MAX19506 ELECTRICAL CHARACTERISTICS (continued) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC ELECTRICAL CHARACTERISTICS (continued) (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER-MANAGEMENT CHARACTERISTICS Wake-Up Time from Shutdown tWAKE Internal reference, CREFIO = 0.1µF (10τ) 5 ms Wake-Up Time from Standby tWAKE Internal reference 15 µs SERIAL-PORT INTERFACE TIMING (Note 2) (Figure 7) SCLK Period tSCLK 50 ns SCLK to CS Setup Time tCSS 10 ns SCLK to CS Hold Time tCSH 10 ns SDIN to SCLK Setup Time tSDS Serial-data write 10 ns SDIN to SCLK Hold Time tSDH Serial-data write 0 ns SCLK to SDIN Output Data Delay tSDD Serial-data read 10 ns TIMING CHARACTERISTICS—DUAL BUS PARALLEL MODE (Figure 9), (Default Timing see Table 5) Clock Pulse-Width High tCH 5.0 ns Clock Pulse-Width Low tCL 5.0 ns Clock Duty Cycle Data Delay After Rising Edge of CLK+ tCH/tCLK tDD 30 to 70 CL = 10pF, VOVDD = 1.8V (Note 2) 2.9 CL = 10pF, VOVDD = 3.3V 4.8 % 6.6 3.6 ns Data to DCLK Setup Time tSETUP CL = 10pF, VOVDD = 1.8V (Note 2) 8.2 8.8 ns Data to DCLK Hold Time tHOLD CL = 10pF, VOVDD = 1.8V (Note 2) 0.7 1.2 ns TIMING CHARACTERISTICS—MULTIPLEXED BUS PARALLEL MODE (Figure 10), (Default Timing see Table 5) Clock Pulse-Width High Clock Pulse-Width Low Clock Duty Cycle Data Delay After Rising Edge of CLK+ tCH 5.0 ns tCL 5.0 ns tCH/tCLK 30 to 70 % tDD CL = 10pF, VOVDD = 1.8V (Note 2) 2.6 CL = 10pF, VOVDD = 3.3V 4.4 6.5 3.5 ns Data to DCLK Setup Time tSETUP CL = 10pF, VOVDD = 1.8V (Note 2) 2.8 4.0 ns Data to DCLK Hold Time tHOLD CL = 10pF, VOVDD = 1.8V (Note 2) -0.2 1.0 ns DCLK Duty Cycle tDCH/tCLK CL = 10pF, VOVDD = 1.8V (Note 2) 42 50 59 % MUX Data Duty Cycle tCHA/tCLK CL = 10pF, VOVDD = 1.8V (Note 2) 40 50 65 % TIMING CHARACTERISTICS—SYNCHRONIZATION (Figure 12) Setup Time for Valid Clock Edge tSUV Edge mode (Note 2) 0.7 ns Hold-Off Time for Invalid Clock Edge tHO Edge mode (Note 2) 0.5 ns Minimum Synchronization Pulse Width 6 Relative to input clock period 2 _______________________________________________________________________________________ Cycles Dual-Channel, 8-Bit, 100Msps ADC (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER REQUIREMENTS Analog Supply Voltage VAVDD Digital Output Supply Voltage VOVDD Low-level VAVDD 1.7 1.9 High-level VAVDD (regulator mode, invoked automatically) 2.3 3.5 1.7 Dual channel Analog Supply Current Analog Power Dissipation Digital Output Supply Current IAVDD PDA IOVDD 3.5 63 37 Standby mode 9.5 13 Power-down mode 0.65 0.9 Power-down mode, VAVDD = 3.3V 1.6 Dual channel 113 Dual channel, VAVDD = 3.3V 208 Single channel active 67 Standby mode 17 24 Power-down mode 1.2 1.6 Power-down mode, VAVDD = 3.3V 2.9 Power-down mode 17 < 0.1 V 77 Single channel active Dual-channel mode, CL = 10pF V mA 139 mW mA Note 1: Specifications at ≥ +25°C guaranteed by production test, specifications at < +25°C guaranteed by design and characterization. Note 2: Guaranteed by design and characterization. _______________________________________________________________________________________ 7 MAX19506 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = +25°C, unless otherwise noted.) -40 -50 -60 -30 -40 -50 -60 -30 -40 -60 -80 -80 -80 -90 -90 30 40 50 -90 0 10 20 -60 -20 -30 -40 -50 -60 -20 -40 -50 -60 -70 -80 -80 -90 -90 -90 -100 -100 30 40 0 50 10 20 30 40 10 20 30 40 FREQUENCY (MHz) FREQUENCY (MHz) INTEGRAL NONLINEARITY vs. DIGITAL OUTPUT CODE DIFFERENTIAL NONLINEARITY vs. DIGITAL OUTPUT CODE PERFORMANCE vs. INPUT FREQUENCY 0.06 0.04 DNL (LSB) 0.04 0.02 0 -0.02 0.02 0 -0.02 -0.04 -0.04 -0.06 -0.06 -0.08 -0.08 -0.10 -0.10 64 128 192 DIGITAL OUTPUT CODE 256 SFDR1 80 75 50 MAX19506 toc09 0.08 PERFORMANCE (dBFS) 0.06 85 MAX19506 toc08 0.10 MAX19506 toc07 0.08 0 0 50 FREQUENCY (MHz) 0.10 50.0 -30 -80 20 fIN1 = 172.50290MHz fIN2 = 177.49523MHz -10 -70 10 37.5 175MHz TWO-TONE FFT PLOT -70 0 25.0 0 AMPLITUDE (dBFS) -50 fIN1 = 71.501922MHz fIN2 = 68.509674MHz -10 AMPLITUDE (dBFS) -40 12.5 FREQUENCY (MHz) 0 MAX19506 toc04 fIN = 175.099945MHz AIN = -0.492dBFS SNR = 49.240dB SINAD = 49.223dB THD = -73.096dBc SFDR1 = 76.572dBc SFDR2 = 69.564dBc -30 0 50 70MHz TWO-TONE FFT PLOT 175MHz INPUT FFT PLOT -20 40 FREQUENCY (MHz) 0 -10 30 MAX19506 toc05 20 MAX19506 toc03 -50 -70 FREQUENCY (MHz) AMPLITUDE (dBFS) -20 -70 10 fIN = 70.0935363MHz AIN = -0.517dBFS SNR = 49.391dB SINAD = 49.378dB THD = -80.148dBc SFDR1 = 81.688dBc SFDR2 = 68.992dBc -10 -70 0 8 MAX19506 toc02 -20 0 AMPLITUDE (dBFS) -30 fIN = 2.99911499MHz AIN = -0.489dBFS SNR = 49.348dB SINAD = 49.326dB THD = -72.29dBc SFDR1 = 73.498dBc SFDR2 = 70.34dBc -10 AMPLITUDE (dBFS) AMPLITUDE (dBFS) -20 MAX19506 toc01 fIN = 2.99911499MHz AIN = -0.476dBFS SNR = 49.169dB SINAD = 49.165dB THD = -79.250dBc SFDR1 = 87.836dBc SFDR2 = 68.557dBc -10 70MHz INPUT FFT PLOT 3MHz SINGLE-ENDED INPUT FFT PLOT 0 MAX19506 toc06 3MHz INPUT FFT PLOT 0 INL (LSB) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC -THD 70 65 SFDR2 60 SNR 55 SINAD 50 45 0 64 128 192 DIGITAL OUTPUT CODE 256 0 100 200 300 INPUT FREQUENCY (MHz) _______________________________________________________________________________________ 400 Dual-Channel, 8-Bit, 100Msps ADC 70 65 SFDR1 60 SINAD SNR 55 10 20 30 40 50 60 65 60 -THD 70 SFDR2 60 SINAD SNR 55 SNR 50 SINAD -60 -50 -40 -30 -20 45 60 0 -10 70 80 90 100 PERFORMANCE vs. COMMON-MODE VOLTAGE PERFORMANCE vs. ANALOG SUPPLY VOLTAGE PERFORMANCE vs. ANALOG SUPPLY VOLTAGE 60 SNR 75 70 50 45 0.95 1.15 1.35 SINAD SNR 55 45 0.75 SFDR2 60 50 0.55 -THD 80 SFDR1 75 70 65 SFDR2 60 SINAD SNR 55 50 45 1.65 1.70 1.75 1.80 1.85 1.90 2.3 1.95 2.5 2.7 2.9 3.1 3.3 ANALOG SUPPLY CURRENT vs. SAMPLING FREQUENCY ANALOG SUPPLY CURRENT vs. TEMPERATURE ANALOG SUPPLY CURRENT vs. SUPPLY VOLTAGE 56 54 67 65 63 61 59 57 52 60 65 70 75 80 85 90 95 100 105 110 SAMPLING FREQUENCY (MHz) 67 65 63 61 59 57 55 50 69 ANALOG SUPPLY CURRENT (mA) 58 ANALOG SUPPLY CURRENT (mA) 60 69 3.5 MAX19506 toc18 ANALOG SUPPLY VOLTAGE (V) MAX19506 toc17 ANALOG SUPPLY VOLTAGE (V) MAX19506 toc16 COMMON-MODE VOLTAGE (V) 62 110 MAX19506 toc15 MAX19506 toc14 -THD 65 85 PERFORMANCE (dBFS) SFDR2 SINAD SFDR1 80 PERFORMANCE (dBFS) 70 65 85 MAX19506 toc13 SFDR1 75 64 65 SAMPLING FREQUENCY (Msps) -THD 0.35 -THD 70 ANALOG INPUT AMPLITUDE (dBFS) 80 55 75 INPUT FREQUENCY (MHz) 85 66 SFDR1 45 0 PERFORMANCE (dBFS) 70 SFDR1 80 50 45 ANALOG SUPPLY CURRENT (mA) 75 55 50 68 SFDR2 PERFORMANCE (dBFS) SFDR2 75 80 85 MAX19506 toc11 -THD 85 PERFORMANCE (dBFS) PERFORMANCE (dBFS) 80 MAX19506 toc10 85 PERFORMANCE vs. SAMPLING FREQUENCY PERFORMANCE vs. ANALOG INPUT AMPLITUDE MAX19506 toc12 SINGLE-ENDED PERFORMANCE vs. INPUT FREQUENCY 55 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 1.65 1.70 1.75 1.80 1.85 SUPPLY VOLTAGE (V) 1.90 _______________________________________________________________________________________ 1.95 9 MAX19506 Typical Operating Characteristics (continued) (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = +25°C, unless otherwise noted.) 65.5 65.0 64.5 14 12 10 8 6 4 40 OVDD = 3.6V 35 3.3 3.5 60 70 80 90 100 SAMPLING FREQUENCY (Msps) DIGITAL SUPPLY CURRENT vs. TEMPERATURE OVDD = 3.6V 25 OVDD = 1.8V 15 35 DIGITAL SUPPLY CURRENT (mA) MAX19506 toc22 30 60 10 DUAL BUS 30 25 20 15 10 30 60 80 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 SUPPLY VOLTAGE (V) PERFORMANCE vs. CLOCK DUTY CYCLE 15 10 5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 SUPPLY VOLTAGE (V) 70 65 SFDR2 60 SNR GAIN ERROR vs. TEMPERATURE 0.04 0.03 75 -THD 70 65 SFDR2 60 SNR MAX19506 toc27 SFDR1 80 PERFORMANCE (dBFS) 75 3.5 0.05 GAIN ERROR (%) -THD 55 85 MAX19506 toc25 SFDR1 20 PERFORMANCE vs. TEMPERATURE 85 80 MULTIPLEXED BUS 25 3.4 MAX19506 toc26 0 20 40 TEMPERATURE (°C) 110 0 0 -20 70 80 90 100 SAMPLING FREQUENCY (Msps) DIGITAL SUPPLY CURRENT vs. SUPPLY VOLTAGE 5 -40 10 DIGITAL SUPPLY CURRENT vs. SUPPLY VOLTAGE 35 20 15 110 DIGITAL SUPPLY CURRENT (mA) 2.7 2.9 3.1 SUPPLY VOLTAGE (V) MAX19506 toc23 2.5 20 0 0 2.3 25 5 2 64.0 30 MAX19506 toc24 66.0 OVDD = 1.8V 16 DIGITAL SUPPLY CURRENT (mA) 66.5 MAX19506 toc20 67.0 18 DIGITAL SUPPLY CURRENT (mA) MAX19506 toc19 ANALOG SUPPLY CURRENT (mA) 67.5 DIGITAL SUPPLY CURRENT (mA) DIGITAL SUPPLY CURRENT vs. SAMPLING FREQUENCY DIGITAL SUPPLY CURRENT vs. SAMPLING FREQUENCY MAX19506 toc21 ANALOG SUPPLY CURRENT vs. SUPPLY VOLTAGE PERFORMANCE (dBFS) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC 0.02 0.01 0 -0.01 -0.02 55 -0.03 50 50 SINAD 45 30 35 40 45 50 55 CLOCK DUTY CYCLE (%) 10 60 65 -0.04 SINAD 45 -40 -20 0 -0.05 20 40 TEMPERATURE (°C) 60 80 -40 -20 0 20 40 TEMPERATURE (°C) ______________________________________________________________________________________ 60 80 Dual-Channel, 8-Bit, 100Msps ADC REFERENCE VOLTAGE (V) -0.1 -0.2 -0.3 -0.4 -0.5 1.2495 1.2474 1.2453 -0.6 0 20 40 TEMPERATURE (°C) 60 80 -40 -20 0 20 40 TEMPERATURE (°C) 90 MAX19506 toc31 0.08 0.04 0.02 0 REGULATOR MODE 80 INPUT CURRENT (mA) 0.06 -0.02 VCM = 1.05V 1.0 VCM = 0.9V 0.8 VCM = 0.75V VCM = 0.6V 0.6 0.4 VCM = 0.45V 0.2 60 80 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 INPUT CURRENT vs. COMMON-MODE VOLTAGE GAIN ERROR vs. SUPPLY VOLTAGE GAIN ERROR (%) -20 VCM = 1.2V 1.2 0 1.2432 -40 VCM = 1.35V 1.4 MAX19506 toc32 -0.7 1.6 MAX19506 toc30 0 MAX19506 toc29 0.1 OFFSET ERROR (mV) 1.2516 MAX19506 toc28 0.2 COMMON-MODE REFERENCE VOLTAGE vs. TEMPERATURE REFERENCE VOLTAGE vs. TEMPERATURE COMMON-MODE REFERENCE VOLTAGE (V) OFFSET ERROR vs. TEMPERATURE 70 60 50 -0.04 40 -0.06 -0.08 30 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 SUPPLY VOLTAGE (V) 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 COMMON-MODE VOLTAGE (V) ______________________________________________________________________________________ 11 MAX19506 Typical Operating Characteristics (continued) (VAVDD = VOVDD = 1.8V, internal reference, differential clock, VCLK = 1.5VP-P, fCLK = 100MHz, AIN = -0.5dBFS, data output termination = 50Ω, TA = +25°C, unless otherwise noted.) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Pin Description PIN NAME 1, 12, 13, 48 AVDD Analog Supply Voltage. Bypass each AVDD input pair (1, 48) and (12, 13) to GND with 0.1µF. 2 CMA Channel A Common-Mode Input-Voltage Reference 3 INA+ Channel A Positive Analog Input 4 INA- Channel A Negative Analog Input 5 SPEN Active-Low SPI Enable. Drive high to enable parallel programming mode. 6 REFIO Reference Input/Output. To use internal reference, bypass to GND with a > 0.1µF capacitor. See the Reference Input/Output (REFIO) section for external reference adjustment. 7 SHDN Active-High Power-Down. If SPEN is high (parallel programming mode), a register reset is initiated on the falling edge of SHDN. 8, 21, 22, 32, 33 I.C. 9 INB+ Channel B Positive Analog Input 10 INB- Channel B Negative Analog Input 11 CMB Channel B Common-Mode Input-Voltage Reference 14 SYNC Clock-Divider Mode Synchronization Input 15 CLK+ Clock Positive Input CLK- Clock Negative Input. If CLK- is connected to ground, CLK+ is a single-ended logic-level clock input. Otherwise, CLK+/CLK- are self-biased differential clock inputs. 16 12 FUNCTION Internally Connected. Leave unconnected. 17, 18 GND 19 DORB Channel B Data Over Range Ground. Connect all ground inputs and EP (exposed pad) together. 20 DCLKB Channel B Data Clock 23 D0B Channel B Three-State Digital Output, Bit 0 (LSB) 24 D1B Channel B Three-State Digital Output, Bit 1 25, 36 OVDD 26 D2B Channel B Three-State Digital Output, Bit 2 27 D3B Channel B Three-State Digital Output, Bit 3 28 D4B Channel B Three-State Digital Output, Bit 4 29 D5B Channel B Three-State Digital Output, Bit 5 30 D6B Channel B Three-State Digital Output, Bit 6 31 D7B Channel B Three-State Digital Output, Bit 7 (MSB) 34 D0A Channel A Three-State Digital Output, Bit 0 (LSB) 35 D1A Channel A Three-State Digital Output, Bit 1 37 D2A Channel A Three-State Digital Output, Bit 2 38 D3A Channel A Three-State Digital Output, Bit 3 39 D4A Channel A Three-State Digital Output, Bit 4 Digital Supply Voltage. Bypass each OVDD input to GND with a 0.1µF capacitor. ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC PIN NAME FUNCTION 40 D5A Channel A Three-State Digital Output, Bit 5 41 D6A Channel A Three-State Digital Output, Bit 6 42 D7A Channel A Three-State Digital Output, Bit 7 (MSB) 43 DORA Channel A Data Over Range 44 DCLKA Channel A Data Clock 45 SDIN/FORMAT 46 SCLK/DIV Serial Clock/Clock Divider. Serial clock when SPEN is low. Clock divider when SPEN is high. 47 CS/OUTSEL Serial-Port Select/Data Output Mode. Serial-port select when SPEN is low. Data output mode selection when SPEN is high. — EP SPI Data Input/Format. Serial-data input when SPEN is low. Output data format when SPEN is high. Exposed Pad. Internally connected to GND. Connect to a large ground plane to maximize thermal performance. Detailed Description The MAX19506 uses a 10-stage, fully differential, pipelined architecture (Figure 1) that allows for highspeed conversion while minimizing power consumption. Samples taken at the inputs move progressively through the pipeline stages every half clock cycle. From input to output the total latency is 9 clock cycles. Each pipeline converter stage converts its input voltage to a digital output code. At every stage, except the last, the error between the input voltage and the digital output code is multiplied and passed on to the next pipeline stage. Digital error correction compensates for ADC comparator offsets in each pipeline stage and ensures no missing codes. Figure 2 shows the MAX19506 functional diagram. Analog Inputs and Common-Mode Reference Apply the analog input signal to the analog inputs (INA+/INA- or INB+/INB-), which are connected to the input sampling switch (Figure 3). When the input sampling switch is closed, the input signal is applied to the sampling capacitors through the input switch resistance. The input signal is sampled at the instant the input switch opens. The pipeline ADC processes the sampled voltage and the digital output result is available 9 clock cycles later. Before the input switch is closed to begin the next sampling cycle, the sampling capacitors are reset to the input common-mode potential. Common-mode bias can be provided externally or internally through 2kΩ resistors. In DC-coupled applications, the signal source provides the external bias and the bias current. In AC-coupled applications, the input + MAX19506 Σ x2 − FLASH ADC DAC IN_+ STAGE 1 STAGE 2 STAGE 9 IN_- STAGE 10 END OF PIPELINE DIGITAL ERROR CORRECTION D0_ THROUGH D7_ Figure 1. Pipeline Architecture—Stage Blocks current is supplied by the common-mode input voltage. For example, the input current can be supplied through the center tap of a transformer secondary winding. Alternatively, program the appropriate internal register through the serial-port interface to supply the input DC current through internal 2kΩ resistors (Figure 3). When the input current is supplied through the internal resistors, the input common-mode potential is reduced by the voltage drop across the resistors. The commonmode input reference voltage can be adjusted through programmable register settings from 0.45V to 1.35V in 0.15V increments. The default setting is 0.90V. Use this feature to provide a common-mode output reference to a DC-coupled driving circuit. ______________________________________________________________________________________ 13 MAX19506 Pin Description (continued) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC CLOCK MAX19506 INA+ T/H INA- PIPELINE ADC DIGITAL ERROR CORRECTION D0A–D7A DORA DCLKA CMA REFIO CMB REFERENCE AND BIAS SYSTEM INTERNAL REFERENCE GENERATOR PIPELINE ADC DIGITAL ERROR CORRECTION DATA AND OUTPUT FORMAT OUTPUT DRIVERS OVDD (1.8V TO 3.3V) D0B–D7B INB+ T/H INB- DORB DCLKB CLOCK CLK+ CLOCK DIVIDER CLK- DUTYCYCLE EQUALIZER SYNC AVDD (1.8V OR 2.5V TO 3.3V) REGULATOR AND POWER CONTROL 1.8V INTERNAL CS SERIAL PORT AND CONTROL REGISTERS SCLK SDIN SHDN INTERNAL CONTROL GND SPEN Figure 2. Functional Diagram AVDD CMA RSWITCH 120Ω INA+ CSAMPLE 1.2pF CPAR 0.7pF 2kΩ *VCOM AVDD 2kΩ RSWITCH 120Ω INACPAR 0.7pF CSAMPLE 1.2pF SAMPLING CLOCK MAX19506 *VCOM PROGRAMMABLE FROM 0.45V TO 1.35V. SEE COMMON-MODE REGISTER (08h). Figure 3. Internal Track-and-Hold (T/H) Circuit 14 ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC DECODER INTERNAL GAIN—BYPASS REFIO EXTERNAL GAIN CONTROL—DRIVE REFIO 36kΩ 0.1µF EXTERNAL BYPASS REFIO 1.250V BANDGAP REFERENCE 10kΩ BUFFER 23/32 AVDD CS SCLK SDIN TO CONTROL LOGIC 156kΩ SCALE AND INTERNAL REFERENCE LEVEL SHIFT (CONTROLS ADC GAIN) 3/32 AVDD Figure 4. Simplified Reference Schematic Figure 5. Simplified Parallel-Interface Input Schematic Table1. Parallel-Interface Pin Functionality SPEN SDIN/FORMAT SCLK/DIV CS/OUTSEL DESCRIPTION 0 SDIN SCLK CS SPI interface active. Features are programmed through the serial port (see the Serial Programming Interface section). 1 0 X X Two’s complement 1 AVDD X X Offset binary 1 Unconnected X X Gray code 1 X 0 X Clock divide-by-1 1 X AVDD X Clock divide-by-2 1 X Unconnected X Clock divide-by-4 1 X X 0 CMOS (dual bus) 1 X X AVDD MUX CMOS (channel A data bus) 1 X X Unconnected MUX CMOS (channel B data bus) X = Don’t care. Reference Input/Output (REFIO) Programming and Interface REFIO adjusts the reference potential, which, in turn, adjusts the full-scale range of the ADC. Figure 4 shows a simplified schematic of the reference system. An internal bandgap voltage generator provides an internal reference voltage. The bandgap potential is buffered and applied to REFIO through a 10kΩ resistor. Bypass REFIO with a 0.1µF capacitor to AGND. The bandgap voltage is applied to a scaling and level-shift circuit, which creates internal reference potentials that establish the full-scale range of the ADC. Apply an external voltage on REFIO to trim the ADC full scale. The allowable adjustment range is +5/-15%. The REFIO-to-ADC gain transfer function is: VFS = 1.5 x [VREFIO/1.25] Volts There are two ways to control the MAX19506 operating modes. Full feature selection is available using the SPI interface, while the parallel interface offers a limited set of commonly used features. The programming mode is selected using the SPEN input. Drive SPEN low for SPI interface; drive SPEN high for parallel interface. Parallel Interface The parallel interface offers a pin-programmable interface with a limited feature set. Connect SPEN to AVDD to enable the parallel interface. See Table 1 for pin functionality; see Figure 5 for a simplified parallel-interface input schematic. ______________________________________________________________________________________ 15 MAX19506 29/32 AVDD AVDD MAX19506 Dual-Channel, 8-Bit, 100Msps ADC CS SCLK SDIN R/W A6 A5 A4 R/W A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 DATA WRITE OR READ ADDRESS 0 = WRITE 1 = READ Figure 6. Serial-Interface Communication Cycle tCSH tCSS CS tSCLK SCLK tSDS tSDH tSDD SDIN WRITE READ Figure 7. Serial-Interface Timing Diagram Serial Programming Interface A serial interface programs the MAX19506 control registers through the CS, SDIN, and SCLK inputs. Serial data is shifted into SDIN on the rising edge of SCLK when CS is low. The MAX19506 ignores the data presented at SDIN and SCLK when CS is high. CS must transition high after each read/write operation. SDIN also serves as the serial-data output for reading control registers. The serial interface supports two-byte transfer in a communication cycle. The first byte is a control byte, containing the address and read/write instruction, written to the MAX19506. The second byte is a data byte and can be written to or read from the MAX19506. Figure 6 shows a serial-interface communication cycle. The first SDIN bit clocked in establishes the communi- 16 cation cycle as either a write or read transaction (0 for write operation and 1 for read operation). The following 7 bits specify the address of the register to be written or read. The final 8 SDIN bits are the register data. All address and data bits are clocked in or out MSB first. During a read operation, the MAX19506 serial port drives read data (D7) into SDIN after the falling edge of SCLK following the 8th rising edge of SCLK. Since the minimum hold time on SDIN input is zero, the master can stop driving SDIN any time after the 8th rising edge of SCLK. Subsequent data bits are driven into SDIN on the falling edge of SCLK. Output data in a read operation is latched on the rising edge of SCLK. Figure 7 shows the detailed serial-interface timing diagram. ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC ters are reset to default values. A read operation of register 0Ah returns a status byte with information described in Table 2. Table 2. Register 0Ah Status Byte BIT NO. VALUE 7 0 Reserved DESCRIPTION 6 0 Reserved 5 0 or 1 1 = ROM read in progress 4 0 or 1 1 = ROM read completed and register data is valid (checksum is OK) 3 0 Reserved 2 1 Reserved 1 0 or 1 Reserved 0 0 or 1 1 = Duty-cycle equalizer DLL is locked User-Programmable Registers Table 3. User-Programmable Registers ADDRESS POR DEFAULT 00h 00000011 Power management FUNCTION 01h 00000000 Output format 02h 00000000 Digital output power management 03h 10110110 Data/DCLK timing 04h 00000000 CHA data output termination control 05h 00000000 CHB data output termination control 06h 00000000 Clock divide/data format/test pattern 07h Reserved Reserved—do not use 08h 00000000 Common mode 0Ah — Software reset Power Management (00h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 HPS_SHDN1 STBY_SHDN1 CHB_ON_SHDN1 CHA_ON_SHDN1 HPS_SHDN0 STBY_SHDN0 CHB_ON_SHDN0 CHA_ON_SHDN0 The SHDN input (pin 7) toggles between any two power-management states. The Power Management register defines each power-management state. In the default state, SHDN = 1 shuts down the MAX19506 and SHDN = 0 returns to full power. ______________________________________________________________________________________ 17 MAX19506 Register address 0Ah is a special-function register. Writing data 5Ah to register 0Ah initiates a register reset. When this operation is executed, all control regis- MAX19506 Dual-Channel, 8-Bit, 100Msps ADC In addition to power management, the HPS_SHDN1 and HPS_SHDN0 activate an A+B adder mode. In this mode, the results from both channels are averaged. The MUX_CH bit selects which bus the (A+B)/2 data is presented. Control Bits: HPS_SHDN0 STBY_SHDN0 CHA_ON_SHDN0 CHB_ON_SHDN0 SHDN INPUT = 0* HPS_SHDN1 STBY_SHDN1 CHA_ON_SHDN1 CHB_ON_SHDN1 X 0 0 0 Complete power-down 0 0 0 1 Channel B active, channel A full power-down 0 0 1 0 Channel A active, channel B full power-down 0 X 1 1 Channels A and B active 0 1 0 0 Channels A and B in standby mode 0 1 0 1 Channel B active, channel A standby 0 1 1 0 Channel A active, channel B standby Channels A and B in standby mode SHDN INPUT = 1** 1 1 0 0 1 X X 1 Channels A and B active, output is averaged 1 X 1 X Channels A and B active, output is averaged *HPS_SHDN0, STBY_SHDN0, CHA_ON_SHDN0, and CHB_ON_SHDN0 are active when SHDN = 0. **HPS_SHDN1, STBY_SHDN1, CHA_ON_SHDN1, and CHB_ON_SHDN1 are active when SHDN = 1. X = Don’t care. Note: When HPS_SHDN_ = 1 (A+B adder mode), CHA_ON and CHB_ON must BOTH equal 0 for power-down or standby. Output Format (01h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 0 0 0 BIT_ORDER_B BIT_ORDER_A MUX_CH MUX 0 Bit 7, 6, 5 Set to 0 for proper operation Bit 4 BIT_ORDER_B: Reverse CHB output bit order 0 = Defined data bus pin order (default) 1 = Reverse data bus pin order Bit 3 BIT_ORDER_A: Reverse CHA output bit order 0 = Defined data bus pin order (default) 1 = Reverse data bus pin order Bit 2 MUX_CH: Multiplexed data bus selection 0 = Multiplexed data output on CHA (CHA data presented first, followed by CHB data) (default) 1 = Multiplexed data output on CHB (CHB data presented first, followed by CHA data) Bit 1 MUX: Digital output mode 0 = Dual data bus output mode (default) 1 = Single multiplexed data bus output mode MUX_CH selects the output bus Bit 0 18 Set to 0 for proper operation ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 X X X X PD_DOUT_1 PD_DOUT_0 DIS_DOR DIS_DCLK Bit 7–4 Bit 3, 2 Don’t care PD_DOUT_1, PD_DOUT_0: Power-down digital output state control 00 = Digital output three state (default) 01 = Digital output low 10 = Digital output three state 11 = Digital output high Bit 1 DIS_DOR: DOR driver disable 0 = DOR active (default) 1 = DOR disabled (three state) Bit 0 DIS_DCLK: DCLK driver disable 0 = DCLK active (default) 1 = DCLK disabled (three state) ______________________________________________________________________________________ 19 MAX19506 Digital Output Power Management (02h) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Data/DCLK Timing (03h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 DA_BYPASS DLY_HALF_T DCLKTIME_2 DCLKTIME_1 DCLKTIME_0 DTIME_2 DTIME_1 DTIME_0 Bit 7 DA_BYPASS: Data aligner bypass 0 = Nominal 1 = Bypasses data aligner delay line to minimize output data latency with respect to the input clock. Rising clock to data transition is approximately 6ns with DTIME = 000b settings (default) Bit 6 DLY_HALF_T: Data and DCLK delayed by T/2 0 = Normal, no delay (default) 1 = Delays data and DCLK outputs by T/2 Disabled in MUX data bus mode Bit 5, 4, 3 DCLKTIME_2, DCLKTIME_1, DCLKTIME_0: DCLK timing adjust (controls both channels) 000 = Nominal 001 = +T/16 010 = +2T/16 011 = +3T/16 100 = Reserved, do not use 101 = -1T/16 110 = -2T/16 (default) 111 = -3T/16 Bit 2, 1, 0 DTIME_2, DTIME_1, DTIME_0: Data timing adjust (controls both channels) 000 = Nominal 001 = +T/16 010 = +2T/16 011 = +3T/16 100 = Reserved, do not use 101 = -1T/16 110 = -2T/16 (default) 111 = -3T/16 20 ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 X X CT_DCLK_2_A CT_DCLK_1_A CT_DCLK_0_A CT_DATA_2_A CT_DATA_1_A CT_DATA_0_A Bit 7, 6 Bit 5, 4, 3 Don’t care CT_DCLK_2_A, CT_DCLK_1_A, CT_DCLK_0_A: CHA DCLK termination control 000 = 50Ω (default) 001 = 75Ω 010 = 100Ω 011 = 150Ω 1xx = 300Ω Bit 2, 1, 0 CT_DATA_2_A, CT_DATA_1_A, CT_DATA_0_A: CHA data output termination control 000 = 50Ω (default) 001 = 75Ω 010 = 100Ω 011 = 150Ω 1xx = 300Ω CHB Data Output Termination Control (05h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 X X CT_DCLK_2_B CT_DCLK_1_B CT_DCLK_0_B CT_DATA_2_B CT_DATA_1_B CT_DATA_0_B Bit 7, 6 Don’t care Bit 5, 4, 3 CT_DCLK_2_B, CT_DCLK_1_B, CT_DCLK_0_B: CHB DCLK termination control 000 = 50Ω (default) 001 = 75Ω 010 = 100Ω 011 = 150Ω 1xx = 300Ω Bit 2, 1, 0 CT_DATA_2_B, CT_DATA_1_B, CT_DATA_0_B: CHB data output termination control 000 = 50Ω (default) 001 = 75Ω 010 = 100Ω 011 = 150Ω 1xx = 300Ω ______________________________________________________________________________________ 21 MAX19506 CHA Data Output Termination Control (04h) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Clock Divide/Data Format/Test Pattern (06h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 TEST_PATTERN TEST_DATA FORMAT_1 FORMAT_0 TERM_100 SYNC_MODE DIV1 DIV0 Bit 7 TEST_PATTERN: Test pattern selection 0 = Ramps from 0 to 255 (offset binary) and repeats (subsequent formatting applied) (default) 1 = Data alternates between D[7:0] = 01010101, DOR = 1, and D[7:0] = 10101010, DOR = 0 on both channels Bit 6 TEST_DATA: Data test mode 0 = Normal data output (default) 1 = Outputs test data pattern Bit 5, 4 FORMAT_1, FORMAT_0: Data numerical format 00 = Two’s complement (default) 01 = Offset binary 10 = Gray code 11 = Two’s complement Bit 3 TERM_100: Select 100Ω clock input termination 0 = No termination (default) 1 = 100Ω termination across differential clock inputs Bit 2 SYNC_MODE: Divider synchronization mode select 0 = Slip mode (Figure 11) (default) 1 = Edge mode (Figure 12) Bit 1, 0 DIV1, DIV0: Input clock-divider select 00 = No divider (default) 01 = Divide-by-2 10 = Divide-by-4 11 = No divider Reserved (07h)—Do not write to this register 22 ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC BIT 7 CMI_SELF_B BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 CMI_ADJ_2_B CMI_ADJ_1_B CMI_ADJ_0_B CMI_SELF_A CMI_ADJ_2_A CMI_ADJ_1_A CMI_ADJ_0_A Bit 7 CMI_SELF_B: CHB connect input common-mode to analog inputs 0 = Internal common-mode voltage is NOT applied to inputs (default) 1 = Internal common-mode voltage applied to analog inputs through 2kΩ resistors Bit 6, 5, 4 CMI_ADJ_2_B, CMI_ADJ_1_B, CMI_ADJ_0_B: CHB input common-mode voltage adjustment 000 = 0.900V (default) 001 = 1.050V 010 = 1.200V 011 = 1.350V 100 = 0.900V 101 = 0.750V 110 = 0.600V 111 = 0.450V Bit 3 CMI_SELF_A: CHA connect input common-mode to analog inputs 0 = Internal common-mode voltage is NOT applied to inputs (default) 1 = Internal common-mode voltage applied to analog inputs through 2kΩ resistors Bit 2, 1, 0 CMI_ADJ_2_A, CMI_ADJ_1_A, CMI_ADJ_0_A: CHA input common-mode adjustment 000 = 0.900V (default) 001 = 1.050V 010 = 1.200V 011 = 1.350V 100 = 0.900V 101 = 0.750V 110 = 0.600V 111 = 0.450V Software Reset (0Ah) Bit 7–0 SWRESET: Write 5Ah to initiate software reset ______________________________________________________________________________________ 23 MAX19506 Common Mode (08h) MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Clock Inputs 100Ω TERMINATION (PROGRAMMABLE) CLK+ The input clock interface provides for flexibility in the requirements of the clock driver. The MAX19506 accepts a fully differential clock or single-ended logiclevel clock. For differential clock operation, connect a differential clock to the CLK+ and CLK- inputs. In this mode, the input common mode is established internally to allow for AC-coupling. The differential clock signal can also be DC-coupled if the common mode is constrained to the specified 1V to 1.4V clock input common-mode range. For single-ended operation, connect CLK- to GND and drive the CLK+ input with a logiclevel signal. When the CLK- input is grounded (or pulled below the threshold of the clock mode detection comparator) the differential-to-single-ended conversion stage is disabled and the logic-level inverter path is activated. 2:1 MUX AVDD 5kΩ 50Ω 10kΩ 20kΩ 50Ω SELECT THRESHOLD 5kΩ GND CLK- SELF-BIAS TURNED OFF FOR SINGLE-ENDED CLOCK OR POWER-DOWN. Clock Divider The MAX19506 offers a clock-divider option. Enable clock division either by setting DIV0 and DIV1 through the serial interface; see the Clock Divide/Data Figure 8. Simplified Clock Input Schematic DUAL-BUS OUTPUT MODE SAMPLING INSTANT SAMPLING INSTANT SAMPLING INSTANT tAD SAMPLING INSTANT SAMPLING INSTANT IN_ SAMPLING INSTANT tCLK SAMPLE ON RISING EDGE n tCL tCH n+1 n+2 n+4 n+3 n+5 SAMPLE CLOCK tDD DATA, DOR n-10 n-9 tDC n-8 n-7 n-6 n-5 tHOLD tSETUP DCLK SAMPLE CLOCK IS THE DERIVED CLOCK FROM (CLK+ - CLK-)/CLOCK DIVIDER, IN_ = IN_+ - IN_-. Figure 9. Dual-Bus Output Mode Timing 24 ______________________________________________________________________________________ n-4 Dual-Channel, 8-Bit, 100Msps ADC MAX19506 MUX OUTPUT MODE SAMPLING INSTANT tAD SAMPLING INSTANT SAMPLING INSTANT SAMPLING INSTANT SAMPLING INSTANT SAMPLING INSTANT IN_ tCLK n tCL tCH SAMPLE ON RISING EDGE n+1 n+2 n+3 n+4 n+5 SAMPLE CLOCK tCHA tDD DATA, DOR tCHB CHB CHA CHB CHA CHB CHA CHB CHA CHB CHA CHB CHA CHB n-10 n-9 n-9 n-8 n-8 n-7 n-7 n-6 n-6 n-5 n-5 n-4 n-4 tDC tHOLD tDCH tDCL tSETUP tHOLD tSETUP DCLK SAMPLE CLOCK IS THE DERIVED CLOCK FROM (CLK+ - CLK-)/CLOCK DIVIDER, IN_ = IN_+ - IN_-. MUX_CH (BIT 2, OUTPUT FORMAT 01h) DETERMINES THE OUTPUT BUS AND WHICH CHANNEL DATA IS PRESENTED. Figure 10. Multiplexed Output Mode Timing Format/Test Pattern register (06h) for clock-divider options, or in parallel programming configuration (SPEN = 1) by using the DIV input. System Timing Requirements Figures 9 and 10 depict the relationship between the clock input and output, analog input, sampling event, and data output. The MAX19506 samples on the rising edge of the sampling clock. Output data is valid on the next rising edge of DCLK after a nine-clock internal latency. For applications where the clock is divided, the sample clock is the divided internal clock derived from: [(CLK+ - CLK-)/DIVIDER] Synchronization When using the clock divider, the phase of the internal clock can be different than that of the FPGA, microcontroller, or other MAX19506s in the system. There are two mechanisms to synchronize the internal clock: slip synchronization and edge synchronization. Select the synchronization mode using SYNC_MODE (bit 2) in the Clock Divide/Data Format/Test Pattern register (06h) and drive the SYNCIN input high to synchronize. Slip Synchronization Mode, SYNC_MODE = 0 (default): On the third rising edge of the input clock (CLK) after the rising edge of SYNC (provided set-up and hold times are met), the divided output is forced to skip a state transition (Figure 11). Edge Synchronization Mode, SYNC_MODE = 1: On the third rising edge of the input clock (CLK) after the rising edge of SYNC (provided set-up and hold times are met), the divided output is forced to state 0. A divided clock rising edge occurs on the fourth (/2 mode) or fifth (/4 mode) rising edge of CLK, after a valid rising edge of SYNC (Figure 12). ______________________________________________________________________________________ 25 MAX19506 Dual-Channel, 8-Bit, 100Msps ADC tHO DIVIDE-BY-2 SLIP SYNCRONIZATION tSUV tSUV = SET-UP TIME FOR VALID CLOCK EDGE. tHO = HOLD-OFF TIME FOR INVALID CLOCK EDGE. SYNCIN 1 2 3 4 2x INPUT CLK SLIP (0) (1) (0) (0) (1) (0) (1) (0) (1) (0) (1) (0) (1) (0) (1) (1) (0) (1) (0) (1) (0) (1) (0) (1) 1x DIVIDED CLK (STATE) tHO tSUV DIVIDE-BY-4 SLIP SYNCHRONIZATION SYNCIN 1 2 3 4 5 4x INPUT CLK SLIP (0) (1) (2) (3) (3) (0) (1) (2) (3) (0) (1) (2) (3) (1) (2) (3) (0) (0) (1) (2) (3) (0) (1) (2) (3) (0) (2) (3) (0) (1) (1) (2) (3) (0) (1) (2) (3) (0) (1) (3) (0) (1) (2) (2) (3) (0) (1) (2) (3) (0) (1) (2) 1x DIVIDED CLK (STATE) Figure 11. Slip Synchronization Mode 26 ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC MAX19506 tHO DIVIDE-BY-2 EDGE SYNCRONIZATION tSUV tSUV = SET-UP TIME FOR VALID CLOCK EDGE. tHO = HOLD-OFF TIME FOR INVALID CLOCK EDGE. SYNCIN 1 2 3 4 2x INPUT CLK FORCE TO 0 (0) (1) (0) (0) (1) (0) (1) (0) (1) (0) (1) (0) (1) (1) (0) (1) (0) (1) (0) (1) (0) (1) (0) (1) (0) (1) 1x DIVIDED CLK (STATE) tHO tSUV DIVIDE-BY-4 EDGE SYNCHRONIZATION SYNCIN 1 2 3 4 5 4x INPUT CLK FORCE TO 0 (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) (1) (2) (3) (0) (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) (3) (0) (1) (2) (0) (1) (2) (3) (0) (1) (2) (3) (0) (1) 1x DIVIDED CLK (STATE) Figure 12. Edge Synchronization Mode ______________________________________________________________________________________ 27 MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Table 4. Data Timing Controls DATA TIMING CONTROL DESCRIPTION DA_BYPASS Data aligner bypass. When this control is active (high), data and DCLK delay is reduced by approximately 2.6ns (relative to DA_BYPASS = 0). DLY_HALF_T When this control is active, data output is delayed by half clock period (T/2). This control does not delay data output if MUX mode is active. DTIME<2:0> Allows adjustment of data output delay in T/16 increments, where T is the sample clock period. Provides adjustment of DCLK delay in T/16 increments, where T is the sample clock period. When DTIME and DCLKTIME are adjusted to the same setting, the rising edge of DCLK occurs T/8 prior to data transitions. DCLKTIME<2:0> Table 5. Data Timing Control Default Settings DATA TIMING CONTROL DEFAULT DA_BYPASS 1 Data aligner disabled DLY_HALF_T 0 No delay DTIME<2:0> 110 -2T/16 (1.25ns at 100Msps) DCLKTIME<2:0> 110 -2T/16 (1.25ns at 100Msps) DESCRIPTION Digital Outputs The MAX19506 features a dual CMOS, multiplexable, reversible data bus. In parallel programming mode, configure the data outputs (D0_–D7_) for offset binary, two’s complement, or gray code using the FORMAT input. Select multiplexed or dual-bus operation using the OUTSEL input. See the Output Format register (01h) for details on output formatting using the SPI interface. The SPI interface offers additional flexibility where D0_–D7_ are reversed, so the LSB appears at D7_ and the MSB at D0_. OVDD sets the output voltage; set OVDD between 1.8V and 3.3V. The digital outputs feature programmable output impedance from 50Ω to 300Ω. Set the output impedance for each bus using the CH_ Data Output Termination Control registers (04h and 05h). Programmable Data Timing The MAX19506 provides programmable data timing control to allow for optimization of timing characteristics to meet the system timing requirements. The timing adjustment feature also allows for ADC performance improvements by shifting the data output transition away from the sampling instant. The data timing control signals are summarized in Table 4. The default settings for timing adjustment controls are given in Table 5. Many applications will not require adjustment from the default settings. The effects of the data timing adjustment settings are illustrated in Figures 13 and 14. The x axis is sampling rate and the y axis is data delay in units of clock period. 28 The solid lines are the nominal data timing characteristics for the 14 available states of DTIME and DLY_HALF_T. The heavy line represents the nominal data timing characteristics for the default settings. Note that the default timing adjustment setting for the MAX19506 100Msps ADC results in an additional period of data latency. Tables 6 and 7 show the recommended timing control settings versus sampling rate. The nominal data timing characteristics versus sampling rate for these recommended timing adjustment settings are shown in Figures 15 and 16. When DA_BYPASS = 1, the DCLKTIME delay setting must be equal to or less than the DTIME delay setting, as shown in Table 8. Power Management The SHDN input (pin 7) toggles between any two powermanagement states. The Power Management register (00h) defines each power-management state. In default state, SHDN = 1 shuts down the MAX19506 and SHDN = 0 returns to full power. Use of the SHDN input is not required for power management. For either state of SHDN, complete power-management flexibility is provided, including individual ADC channel power-management control, through the Power Management register (00h). The available reduced-power modes are shutdown and standby. In standby mode, the reference and duty-cycle equalizer circuits remain active for rapid wake-up time. In standby mode, the externally applied clock signal must remain active for the duty-cycle equalizer to remain locked. Typical wake-up time from standby mode is 15µs. In shutdown mode, all circuits are turned off except for the reference circuit required for the integrated self-sensing voltage regulator. If the regulator is active, there is additional supply current associated with the regulator circuit when the device is in shutdown. Typical wake-up time from shutdown mode is 5ms, which is dominated by the RC time constant on REFIO. ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC RECOMMENDED DATA TIMING vs. SAMPLING RATE 2.0 OVDD = 1.8V DA_BYPASS = 1 DATA DELAY (T FRACTIONAL PERIOD) DATA DELAY (T FRACTIONAL PERIOD) 2.0 1.5 +11/16 +9/16 +7/16 +5/16 +3/16 +1/16 -1/16 -3/16 1.0 0.5 +10/16 +8/16 +6/16 +2/16 0 -2/16 0 OVDD = 1.8V DA_BYPASS = 1 1.5 +11/16 +9/16 +7/16 +5/16 +3/16 +1/16 -1/16 -3/16 1.0 0.5 +10/16 +8/16 +6/16 +2/16 0 -2/16 0 50 60 70 80 90 100 50 60 SAMPLING RATE (Msps) 70 80 90 100 SAMPLING RATE (Msps) Figure 13. Default Data Timing (VOVDD = 1.8V) Figure 15. Recommended Data Timing (VOVDD = 1.8V) FACTORY DEFAULT NOMINAL DATA TIMING vs. SAMPLING RATE RECOMMENDED DATA TIMING vs. SAMPLING RATE 2.0 2.0 OVDD = 3.3V DA_BYPASS = 1 DATA DELAY (T FRACTIONAL PERIOD) DATA DELAY (T FRACTIONAL PERIOD) MAX19506 FACTORY DEFAULT NOMINAL DATA TIMING vs. SAMPLING RATE 1.5 +11/16 +9/16 +7/16 +5/16 +3/16 +1/16 -1/16 -3/16 1.0 0.5 +10/16 +8/16 +6/16 +2/16 0 -2/16 OVDD = 3.3V DA_BYPASS = 1 1.5 +11/16 +9/16 +7/16 +5/16 +3/16 +1/16 -1/16 -3/16 1.0 0.5 +10/16 +8/16 +6/16 +2/16 0 -2/16 0 0 50 60 70 80 90 50 100 60 70 80 90 100 SAMPLING RATE (Msps) SAMPLING RATE (Msps) Figure 14. Default Data Timing (VOVDD = 3.3V) Figure 16. Recommended Data Timing (VOVDD = 3.3V) Table 6. Recommended Timing Adjustments (VOVDD = 1.8V) SAMPLING RATE (Msps) VOVDD = 1.8V FROM TO DA_BYPASS DLY_HALF_T DTIME<2:0> DCLKTIME<2:0> 50 55 1 0 101 101 55 65 1 0 110 110 65 75 1 0 111 111 75 86 1 1 011 011 86 96 1 1 010 010 96 100 1 1 001 001 ______________________________________________________________________________________ 29 MAX19506 Dual-Channel, 8-Bit, 100Msps ADC Table 7. Recommended Timing Adjustments (VOVDD = 3.3V) SAMPLING RATE (Msps) VOVDD = 3.3V FROM TO DA_BYPASS DLY_HALF_T DTIME<2:0> DCLKTIME<2:0> 50 63 1 0 000 000 63 77 1 0 101 101 77 91 1 0 110 110 91 100 1 0 111 111 Table 8. Allowed Settings of DCLKTIME and DTIME for DA_BYPASS = 1 DTIME<2:0> ALLOWED DCLKTIME<2:0> SETTINGS 111 (-3T/16) 111 (-3T/16) 110 (-2T/16) 110 (-2T/16); 111 (-3T/16) 101 (-1T/16) 101 (-1T/16); 110 (-2T/16); 111 (-3T/16) 000 (nominal) 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16) 001 (+1T/16) 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16) 010 (+2T/16) 010 (+2T/16); 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16) 011 (+3T/16) 011 (+3T/16); 010 (+2T/16); 001 (+1T/16); 000 (nominal); 101 (-1T/16); 110 (-2T/16); 111 (-3T/16) Table 9. Reset Methods RESET MODE DESCRIPTION Power-On Reset Upon power-up (AVDD supply voltage and clock signal applied), the POR (power-on-reset) circuit initiates a register reset. Software Reset Write data 5Ah to address 0Ah to initiate register reset. Hardware Reset A register reset is initiated by the falling edge on the SHDN pin when SPEN is high. Integrated Voltage Regulator Power-On and Reset The MAX19506 includes an integrated self-sensing linear voltage regulator on the analog supply (AVDD). See Figure 17. When the applied voltage on AVDD is below 2V, the voltage regulator is bypassed, and the core analog circuitry operates from the externally applied voltage. If the applied voltage on AVDD is higher than 2V, the regulator bypass switches off, and voltage regulator mode is enabled. When in voltage regulation mode, the internal-core analog circuitry operates from a stable 1.8V supply voltage provided by the regulator. The regulator provides an output voltage of 1.8V over a 2.3V to 3.5V AVDD input-voltage range. Since the power-supply current is constant over this voltage range, analog power dissipation is proportional to the applied voltage. The user-programmable register default settings and other factory-programmed settings are stored in nonvolatile memory. Upon device power-up, these values are loaded into the control registers. This operation occurs after application of supply voltage to AVDD and application of an input clock signal. The register values are retained as long as AVDD is applied. While AVDD is applied, the registers can be reset, which will overwrite all user-programmed registers with the default values. This reset operation can be initiated by software command through the serial-port interface or by hardware control using the SPEN and SHDN inputs. The reset time is proportional to the ADC clock period and requires 85µs at 100Msps. Table 9 summarizes the reset methods. 30 ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC MAX19506 AVDD (PINS 1, 12, 13, 48) REGULATOR IN 2.3V TO 3.5V OUT 1.8V ENABLE INTERNAL ANALOG CIRCUITS REFERENCE GND Figure 17. Integrated Voltage Regulator Applications Information Analog Inputs IN_+ 0.1µF 1 VIN 6 36.5Ω 0.5% MAX19506 T1 N.C. 5 2 Transformer-Coupled Differential Analog Input The MAX19506 provides better SFDR and THD with fully differential input signals than a single-ended input drive. In differential input mode, even-order harmonics are lower as both inputs are balanced, and each of the ADC inputs only require half the signal swing compared to single-ended input mode. An RF transformer (Figure 18) provides an excellent solution for converting a single-ended signal to a fully differential signal. Connecting the center tap of the transformer to CM_ provides a common-mode voltage. The transformer shown has an impedance ratio of 1:1.4. Alternatively, a different step-up transformer can be selected to reduce the drive requirements. A reduced signal swing from the input driver can also improve the overall distortion. The configuration of Figure 18 is good for frequencies up to Nyquist (fCLK/2). CM_ N.C. 0.1µF 3 4 MINI-CIRCUITS 36.5Ω 0.5% ADT1-1WT IN_- Figure 18. Transformer-Coupled Input Drive for Input Frequencies Up to Nyquist IN_+ 0.1µF 1 VIN N.C. 5 T1 6 2 1 75Ω 0.5% N.C. N.C. 5 T2 110Ω 0.5% 6 MAX19506 2 CM_ N.C. 0.1µF 3 4 MINI-CIRCUITS ADT1-1WT 75Ω 0.5% 3 4 MINI-CIRCUITS ADT1-1WT 110Ω 0.5% IN_- Figure 19. Transformer-Coupled Input Drive for Input Frequencies Beyond Nyquist ______________________________________________________________________________________ 31 MAX19506 Dual-Channel, 8-Bit, 100Msps ADC VIN 0.1µF 0.01µF IN_+ MAX4108 CLK+ 0.1µF CLKIN 100Ω 49.9Ω MAX19506 MAX19506 CM_ 100Ω 0.1µF 49.9Ω 0.01µF CLK- IN_0.1µF Figure 20. Single-Ended, AC-Coupled Input Drive Figure 21. Single-Ended-to-Differential Clock Input The circuit of Figure 19 also converts a single-ended input signal to a fully differential signal. Figure 19 utilizes an additional transformer to improve the commonmode rejection allowing high-frequency signals beyond the Nyquist frequency. A set of 75Ω and 110Ω termination resistors provide an equivalent 50Ω termination to the signal source. The second set of termination resistors connect to CM_ providing the correct input common-mode voltage. produce the highest level of signal integrity. Route highspeed digital signal traces away from the sensitive analog traces of either channel. Make sure to isolate the analog input lines to each respective converter to minimize channel-to-channel crosstalk. Keep all signal lines short and free of 90° turns. Single-Ended AC-Coupled Input Signal Figure 20 shows a single-ended, AC-coupled input application. The MAX4108 provides high speed, high bandwidth, low noise, and low distortion to maintain the input signal integrity. Bias voltage is applied to the inputs through internal 2kΩ resistors. See Common Mode register 08h for further details. INL is the deviation of the measured transfer function from a best-fit straight line. Worst-case deviation is defined as INL. DC-Coupled Input The MAX19506’s wide common-mode voltage range (0.4V to 1.4V) allows DC-coupled signals. Ensure that the common-mode voltage remains between 0.4V and 1.4V. Definitions Integral Nonlinearity (INL) Differential Nonlinearity (DNL) DNL is the difference between the measured transfer function step width 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. DNL deviations are measured at each step of the transfer function and the worst-case deviation is defined as DNL. Offset Error Grounding, Bypassing, and Board-Layout Considerations Offset error is a parameter that indicates how well the actual transfer function matches the ideal transfer function at midscale. Ideally, the midscale transition occurs at 0.5 LSB above midscale. The offset error is the amount of deviation between the measured midscale transition point and the ideal midscale transition point. The MAX19506 requires high-speed board-layout design techniques. Locate all bypass capacitors as close as possible to the device, preferably on the same side as the ADC, using surface-mount devices for minimum inductance. Bypass AVDD, OVDD, REFIO, CMA, and CMB with 0.1µF ceramic capacitors to GND. Multilayer boards with ground and power planes Gain error is a figure of merit that indicates how well the slope of the measured transfer function matches the slope of the ideal transfer function based on the specified full-scale input-voltage range. The gain error is defined as the relative error of the measured transfer function and is expressed as a percentage. Clock Input Figure 21 shows a single-ended-to-differential clock input converting circuit. 32 Gain Error ______________________________________________________________________________________ Dual-Channel, 8-Bit, 100Msps ADC Single-Tone Spurious-Free Dynamic Range (SFDR1 and SFDR2) SFDR is the ratio expressed in decibels of the RMS amplitude of the fundamental (maximum signal component) to the RMS amplitude of the next largest spurious component, excluding DC offset. SFDR1 reflects the spurious performance based on worst 2nd-order or 3rd-order harmonic distortion. SFDR2 is defined by the worst spurious component excluding 2nd- and 3rdorder harmonics and DC offset. Signal-to-Noise Ratio (SNR) Total Harmonic Distortion (THD) For a waveform perfectly reconstructed from digital samples, the theoretical maximum SNR is the ratio of the full-scale analog input (RMS value) to the RMS quantization error (residual error). The ideal, theoretical minimum analog-to-digital noise is caused by quantization error only and results directly from the ADC’s resolution (N bits): SNR[max] = 6.02 x N + 1.76 In reality, there are other noise sources besides quantization noise (e.g., thermal noise, reference noise, clock jitter, etc.). SNR is computed by taking the ratio of the RMS signal to the RMS noise. RMS noise includes all spectral components to the Nyquist frequency excluding the fundamental, the first six harmonics (HD2–HD7), and the DC offset. THD is the ratio of the RMS of the first six harmonics of the input signal to the fundamental itself. This is expressed as: ⎛ SIGNALRMS ⎞ SNR = 20 × log ⎜ ⎟ ⎝ NOISERMS ⎠ ⎞ ⎟ ⎟ ⎠ where V1 is the fundamental amplitude and V2–V7 are the amplitudes of the 2nd-order through 7th-order harmonics (HD2–HD7). Third-Order Intermodulation (IM3) IM3 is the total power of the third-order intermodulation products to the Nyquist frequency relative to the total input power of the two input tones fIN1 and fIN2. The individual input tone levels are at -7dBFS. The thirdorder intermodulation products are: 2 x fIN1 - fIN2, 2 x fIN2 - fIN1, 2 x fIN1 + fIN2, 2 x fIN2 + fIN1. Aperture Delay Signal-to-Noise and Distortion (SINAD) SINAD is computed by taking the ratio of the RMS signal to the RMS noise plus the RMS distortion. RMS noise includes all spectral components to the Nyquist frequency excluding the fundamental, the first six harmonics (HD2–HD7), and the DC offset. RMS distortion includes the first six harmonics (HD2–HD7). ⎛ SIGNALRMS SINAD = 20 × log ⎜ ⎜ 2 2 ⎝ NOISERMS + DISTORTIONRMS ⎛ V22 + V32 + V4 2 + V52 + V62 + V72 THD = 20 × log ⎜ ⎜ V1 ⎝ ⎞ ⎟ ⎟ ⎠ The input signal is sampled on the rising edge of the sampling clock. There is a small delay between the rising edge of the sampling clock and the actual sampling instant, which is defined as aperture delay (tAD). Aperture Jitter Aperture jitter (tAJ) is defined as the sample-to-sample time variation in the aperture delay. Overdrive Recovery Time Overdrive recovery time is the time required for the ADC to recover from an input transient that exceeds the full-scale limits. The specified overdrive recovery time is measured with an input transient that exceeds the fullscale limits by ±10%. Process Information PROCESS: CMOS ______________________________________________________________________________________ 33 MAX19506 Small-Signal Noise Floor (SSNF) SSNF is the integrated noise and distortion power in the Nyquist band for small-signal inputs. The DC offset is excluded from this noise calculation. For this converter, a small signal is defined as a single tone with an amplitude less than -35dBFS. This parameter captures the thermal and quantization noise characteristics of the converter and can be used to help calculate the overall noise figure of a receive channel. Refer to www.maxim-ic.com for application notes on Thermal + Quantization Noise Floor. Dual-Channel, 8-Bit, 100Msps ADC OVDD D2B D3B D4B D5B D6B D7B I.C. I.C. D0A OVDD TOP VIEW D1A MAX19506 Pin Configuration 36 35 34 33 32 31 30 29 28 27 26 25 D2A 37 24 D1B D3A 38 23 D0B D4A 39 22 I.C. D5A 40 21 I.C. D6A 41 20 DCLKB D7A 42 19 DORB MAX19506 DORA 43 18 GND DCLKA 44 17 GND SDIN/FORMAT 45 16 CLK- SCLK/DIV 46 15 CLK+ CS/OUTSEL 47 14 SYNC 13 AVDD 3 4 5 6 7 8 9 10 11 12 INA+ INA- SPEN REFIO SHDN I.C. INB+ INB- CMB 2 AVDD 1 CMA 48 AVDD AVDD *EP + *EXPOSED PAD Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 48 TQFN-EP T4877-4 21-0144 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. 34 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.