0
登录后你可以
  • 下载海量资料
  • 学习在线课程
  • 观看技术视频
  • 写文章/发帖/加入社区
创作中心
发布
  • 发文章

  • 发资料

  • 发帖

  • 提问

  • 发视频

创作活动
ADS5485IRGCT

ADS5485IRGCT

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    VFQFN64

  • 描述:

    IC ADC 16BIT PIPELINED 64VQFN

  • 数据手册
  • 价格&库存
ADS5485IRGCT 数据手册
ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 16-Bit, 170/200-MSPS Analog-to-Digital Converters Check for Samples: ADS5484 ADS5485 FEATURES APPLICATIONS • • • • • • • • • • • • • • 1 23 • • 170/200-MSPS Sample Rates 16-Bit Resolution, 78 dBFS Noise Floor SFDR = 95 dBc On-Chip High Impedance Analog Buffer Efficient DDR LVDS-Compatible Outputs Power-Down Mode: 70 mW Pin-for-Pin with ADS5483/5482/5481, 135/105/80-MSPS ADCs QFN-64 PowerPAD™ Package (9 mm × 9 mm footprint) Industrial Temperature Range: –40°C to 85°C Wireless Infrastructure Test and Measurement Instrumentation Software-Defined Radio Data Acquisition Power Amplifier Linearization Radar Medical Imaging DESCRIPTION The ADS5484/ADS5485 (ADS548x) is a 16-bit family of analog-to-digital converters (ADCs) that operate from both a 5-V supply and 3.3-V supply while providing LVDS-compatible digital outputs. The ADS548x integrated analog input buffer isolates the internal switching of the onboard track and hold (T & H) from disturbing the signal source while providing a high-impedance input. An internal reference generator is provided to simplify the system design. Internal dither is available to improve SFDR. These devices are drop-in compatible to the ADS5483/5482/5481, creating a pin-compatible family from 80 – 200 MSPS. Designed for highest total ENOB, the ADS548x family has outstanding low noise performance and spurious-free dynamic range. The ADS548x family is available in a QFN-64 PowerPAD package. The devices are built on Texas Instruments complementary bipolar process (BiCom3) and are specified over the full industrial temperature range (–40°C to 85°C). SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 100 78 170 MSPS, Dither Enabled 90 170 MSPS, Dither Enabled 76 170 MSPS, No Dither SNR − dBFS SFDR − dBc 170 MSPS, No Dither 77 80 200 MSPS, Dither Enabled 70 75 74 200 MSPS, No Dither 73 72 200 MSPS, No Dither 200 MSPS, Dither Enabled 71 60 70 0 50 100 150 200 fIN − Input Frequency − MHz 250 300 G001 0 50 100 150 200 250 300 fIN − Input Frequency − MHz G002 1 2 3 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2008–2009, Texas Instruments Incorporated ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. Table 1. PACKAGE/ORDERING INFORMATION (1) PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ADS5484 QFN-64 RGC –40°C to 85°C AZ5484 ADS5485 (1) 2 QFN-64 RGC –40°C to 85°C AZ5485 ORDERING NUMBER TRANSPORT MEDIA, QUANTITY ADS5484IRGCT Tape and reel, 250 ADS5484IRGCR Tape and reel, 2000 ADS5485IRGCT Tape and reel, 250 ADS5485IRGCR Tape and reel, 2000 For the most current product and ordering information see the Package Option Addendum located at the end of this document, or see the TI website at www.ti.com.. Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ABSOLUTE MAXIMUM RATINGS (1) Over operating free-air temperature range, unless otherwise noted. Supply voltage ADS5484, ADS5485 UNIT AVDD5 to GND 6 V AVDD3 to GND 5 V DVDD3 to GND 5 V –0.3 to (AVDD5 + 0.3) V ±4 V –0.3 to (AVDD3 + 0.3) V Analog input to GND AC signal. Valid when AVDD5 is within normal operating range. When AVDD5 is off, analog inputs should be < 0.5 V. If not, the protection diode between the inputs and AVDD5 becomes forward-biased and could be damaged or shorten device lifetime (see Figure 30). Short transient conditions during power on/off are not a concern. Analog INP to INM DC signal Clock input to GND Valid when AVDD3 is within normal operating range. When AVDD3 is off, clock inputs should be < 0.5 V. If not, the protection diode between the inputs and AVDD3 becomes forward-biased and could be damaged or shorten device lifetime (see Figure 37). Short transient conditions during power on/off are not a concern. CLKP to CLKM Digital data output to GND ±2.5 V –0.3 to (DVDD3 + 0.3) V Digital data output plus-to-minus Operating temperature range Maximum junction temperature Storage temperature range ESD, human-body model (HBM) (1) ±1 V –40 to 85 °C 150 °C –65 to 150 °C 2 kV Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. Kirkendall voidings and current density information for calculation of expected lifetime are available upon request. THERMAL CHARACTERISTICS (1) PARAMETER RθJA (1) TEST CONDITIONS TYP Soldered thermal pad, no airflow 20 Soldered thermal pad, 150-LFM airflow 16 RθJC Thermal resistance from the junction to the package case (top) RθJP Thermal resistance from the junction to the thermal pad (bottom) 7 UNIT °C/W 0.2 Using 49 thermal vias ( 7 × 7 array). See PowerPAD Package in the Application Information section. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 3 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com RECOMMENDED OPERATING CONDITIONS ADS5484, ADS5485 MIN NOM MAX UNIT SUPPLIES AVDD5 Analog supply voltage 4.75 5 5.25 V AVDD3 Analog supply voltage 3.15 3.3 3.45 V DVDD3 Output driver supply voltage 3 3.3 3.6 V ANALOG INPUT Differential input voltage range VCM 3 Input common-mode voltage VPP 3.1 V 5 pF 100 Ω DIGITAL OUTPUT (DRY, DATA) Maximum differential output load (parasitic or intentional) Differential output resistance CLOCK INPUT (CLK) CLK input sample rate (sine wave) 10 Max Rated Clock Clock amplitude, differential sine wave (see Figure 39) 1.5 5 Clock duty cycle (see Figure 44) TA 45% Operating free-air temperature 50% MSPS VPP 55% –40 +85 °C ELECTRICAL CHARACTERISTICS (ADS5484, ADS5485) Typical values at TA = 25°C: minimum and maximum values over full temperature range TMIN = –40°C to TMAX = 85°C, sampling rate = max rated, 50% clock duty cycle, AVDD5 = 5 V, AVDD3 = 3.3 V, DVDD3 = 3.3 V, –1 dBFS differential input, and 3-VPP differential clock, unless otherwise noted. PARAMETER TEST CONDITIONS ADS5484 MIN TYP ADS5485 MAX MIN TYP MAX UNIT Clock rate 170 200 MSPS Resolution 16 16 Bits ANALOG INPUTS Differential input voltage range Analog input common-mode voltage Self-biased; see VCM specification below Input resistance (dc) Each input to VCM Input capacitance Each input to GND (unsoldered package) Analog input bandwidth (–3dB) CMRR Common-mode rejection ratio Common-mode signal 70 MHz (see Figure 26) 3 3 VPP 3.1 3.1 V 1000 1000 Ω 3.5 3.5 pF 730 730 MHz 65 65 dB 1.2 1.2 V INTERNAL REFERENCE VOLTAGE VREF Reference voltage VCM Analog input common-mode voltage reference output VCM temperature coefficient 4 Submit Documentation Feedback With internal voltage reference 2.9 3.1 3.3 -1 2.9 3.1 -1 3.3 V mV/°C Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ELECTRICAL CHARACTERISTICS (ADS5484, ADS5485) (continued) Typical values at TA = 25°C: minimum and maximum values over full temperature range TMIN = –40°C to TMAX = 85°C, sampling rate = max rated, 50% clock duty cycle, AVDD5 = 5 V, AVDD3 = 3.3 V, DVDD3 = 3.3 V, –1 dBFS differential input, and 3-VPP differential clock, unless otherwise noted. PARAMETER TEST CONDITIONS ADS5484 ADS5485 UNIT MIN TYP MAX MIN TYP MAX -0.99 ±0.5 1.0 -0.99 ±0.5 1.0 LSB -10 ±3 +10 -10 ±3 +10 LSB 15 -15 DYNAMIC ACCURACY DNL INL Differential nonlinearity error No missing codes, fIN = 30 MHz Integral nonlinearity error fIN = 30 MHz Offset error -15 Offset temperature coefficient -0.02 Gain error -6 Gain temperature coefficient ±2 15 -0.02 6 -6 -0.01 ±2 mV mV/°C 6 -0.01 %FS mV/°C POWER SUPPLY IAVDD5 5-V analog current IAVDD3 3.3-V analog current IDVDD3 3.3-V digital/LVDS current VIN = Full-scale, fIN = 30 MHz, fS = Max rated, Normal operation Total power dissipation IAVDD5 5-V analog current IAVDD3 3.3-V analog current IDVDD3 3.3-V digital/LVDS current 5-V analog current IAVDD3 3.3-V analog current IDVDD3 3.3-V digital/LVDS current Light sleep mode (PDWNF = H, PDWNS = L) PSRR Deep sleep mode (PDWNF = L, PDWNS = H) From PDWNF disabled From PDWNS disabled AVDD5 supply Power-supply rejection ratio, Without 0.1-μF board supply capacitors, with 1-MHz supply noise (see Figure 46) DVDD3 supply 330 mA 126 150 mA 60 65 60 65 mA 2.16 2.35 2.16 2.35 W 98 mA 35 35 mA 0.07 0.07 680 600 mA 680 mW 13 13 mA 1 1 mA 0.07 0.07 70 Slow wake-up time (deep sleep) AVDD3 supply 310 150 600 Total power dissipation Fast wake-up time (light sleep) 330 126 98 Total power dissipation IAVDD5 310 100 70 600 mA 100 mW 600 μS 6 6 mS 60 60 dB 80 80 dB 95 95 dB DYNAMIC AC CHARACTERISTICS SNR SFDR HD2 Signal-to-noise ratio, dither disabled Spurious-free dynamic range, dither disabled Second-harmonic, dither disabled fIN = 10 MHz 75 76.8 73.5 fIN = 30 MHz 74.5 75.9 73 fIN = 70 MHz fIN = 130 MHz 75.7 73.5 75.7 fIN = 170 MHz 75.6 fIN = 230 MHz 74.9 72 84 fIN = 30 MHz 84 91 82 87 86 fIN = 170 MHz 81 fIN = 230 MHz 73 fIN = 10 MHz 84 fIN = 30 MHz 84 fIN = 70 MHz fIN = 130 MHz 78 90 85 73 84 95 82 100 95 95 78 85 fIN = 170 MHz 81 78 fIN = 230 MHz 73 73 Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 dBc 78 100 87 93 87 95 78 dBFS 74.4 95 78 74.8 74.8 84 fIN = 130 MHz 75 75 fIN = 10 MHz fIN = 70 MHz 75.8 dBc Submit Documentation Feedback 5 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com ELECTRICAL CHARACTERISTICS (ADS5484, ADS5485) (continued) Typical values at TA = 25°C: minimum and maximum values over full temperature range TMIN = –40°C to TMAX = 85°C, sampling rate = max rated, 50% clock duty cycle, AVDD5 = 5 V, AVDD3 = 3.3 V, DVDD3 = 3.3 V, –1 dBFS differential input, and 3-VPP differential clock, unless otherwise noted. PARAMETER HD3 Third-harmonic, dither disabled Worst harmonic/spur (other than HD2 and HD3), dither disabled THD SINAD IMD ENOB Noise Total harmonic distortion, dither disabled Signal-to-noise and distortion, dither disabled Two-tone SFDR (worst spurious or IMD) TEST CONDITIONS ADS5484 MIN TYP fIN = 10 MHz 84 fIN = 30 MHz 84 fIN = 70 MHz fIN = 130 MHz MIN TYP 97 84 99 91 82 87 78 82 fIN = 230 MHz 73 fIN = 10 MHz 84 fIN = 30 MHz 84 fIN = 70 MHz 78 84 91 82 90 87 78 92 81 fIN = 30 MHz 81 86 79 86 75 78 fIN = 230 MHz 70 fIN = 10 MHz 73.5 fIN = 30 MHz 73 fIN = 70 MHz fIN = 130 MHz 75 92 85 70 75.8 71.5 74.6 75 71 73.8 70 72.9 73.7 73.8 fIN = 170 MHz 72.9 71.7 fIN = 230 MHz 68.7 68.4 fIN1 = 29.5 MHz, fIN2 = 30.5 MHz, Each at –7 dBFS 99.1 95.9 fIN1 = 69.5 MHz, fIN2 = 70.5 MHz, Each at –10 dBFS 95.3 95.2 Effective number of bits fIN = 10 MHz (from SINAD in dBc at -1dBFS) RMS idle-channel noise Analog inputs shorted together dBc 81 76 74.3 71.5 dBc 90 85 84 fIN = 170 MHz 90 87 81 fIN = 130 MHz 93 90 fIN = 10 MHz fIN = 70 MHz dBc 85 90 91 fIN = 230 MHz 87 73 96 fIN = 170 MHz UNIT 81 90 78 MAX 87 86 fIN = 170 MHz fIN = 130 MHz ADS5485 MAX dBc dBFS 11.92 12.3 11.58 12.1 Bits 2.9 2.9 LSB rms 78 78 dBFS LVDS DIGITAL OUTPUTS VOD Differential output voltage (±) VOC Common-mode output voltage Assumes a 100-Ω differential load on each LVDS pair and LVDS bias = 3.5 mA 247 350 454 247 350 454 mV 1.125 1.25 1.375 1.125 1.25 1.375 V 0.8 V 1 μA DIGITAL INPUTS VIH High-level input voltage VIL Low-level input voltage IIH High-level input current IIL Low-level input current Input capacitance 6 Submit Documentation Feedback 2 2 V 0.8 PDWNF, PDWNS, DITHER 1 -1 μA -1 2 2 pF Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 TIMING INFORMATION Sample N N+5 N+3 Aperture Delay ta N+1 N+2 N+4 tCLKL N+6 tCLKH CLKP Sampling Clock Input CLKM tDRY DRY_P Data Clock Output DRY_M Latency = 5 Clock Cycles tDATA Dx_y_P Output Data O E E O O E O E O E E O E O Dx_y_M N–1 N E = Even Bits = B0, B2, B4, B6, B8, B10, B12, B14 O = Odd Bits = B1, B3, B5, B7, B9, B11, B13, B15 Dx_y_P/M are LVDS outputs that have two bits per pair (EVEN and ODD). The values for x and y are 0_1, 2_3, 4_5, ... 14_15. T0158-02 Figure 1. Timing Diagram TIMING CHARACTERISTICS (1) Typical values at TA = 25°C: minimum and maximum values over full temperature range TMIN = –40°C to TMAX = 85°C, sampling rate = max rated, 50% clock duty cycle, AVDD5 = 5 V, AVDD3 = 3.3 V, DVDD3 = 3.3 V, and 3-VPP differential clock, unless otherwise noted. PARAMETER ta TEST CONDITIONS MIN Aperture delay Aperture jitter, rms Clock period tCLKH Clock pulse duration, high tCLKL MAX UNIT 200 Internal jitter of the ADC Latency tCLK TYP ps 80 fs 5 cycles 1e9/CLK 100 ns 0.5e9/CLK 50 ns Clock pulse duration, low 0.5e9/CLK 50 ns tDRY CLK to DRY delay time (2) 1500 1900 2300 ps tDATA CLK to DATA delay time (2) 1400 1900 2400 ps tSKEW DATA to DRY skew –500 0 500 ps tRISE DRY/DATA rise time tFALL DRY/DATA fall time (1) (2) CLK = max rated clock for that part number Zero crossing, 5-pF parasitic to GND tDATA – tDRY, 5-pF parasitic to GND 5-pF parasitic to GND 500 ps 500 ps Timing parameters are assured by design or characterization, but not production tested. DRY and DATA are updated on the rising edge of CLK input. The latency must be added to tDATA to determine the overall propagation delay. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 7 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com PIN CONFIGURATION D14_15_P D14_15_M D12_13_P D12_13_M D10_11_P D10_11_M D8_9_P D8_9_M DRY_P DRY_M DVDD3 DGND 63 62 61 60 59 58 57 56 55 54 53 52 51 50 D6_7_M DVDD3 64 D6_7_P DGND ADS548x RGC Package (Top View) 49 48 D4_5_P 2 47 D4_5_M AGND 3 46 D2_3_P REF 4 45 D2_3_M NC 5 44 D0_1_P NC 6 43 D0_1_M AGND 7 42 DVDD3 AVDD5 8 41 DGND AVDD5 1 AVDD5 AGND NC AGND 13 36 DITHER AVDD5 14 35 PDWNS AVDD3 15 34 PDWNF 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 33 31 32 LVDSB AGND VCM AVDD3 37 AVDD5 12 AGND INM AVDD3 NC AVDD5 38 AGND 11 AVDD3 INP AVDD5 NC AGND 39 CLKP 10 CLKM AGND AGND NC AVDD3 40 AVDD5 9 AGND AVDD3 P0056-08 8 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 Table 2. PIN FUNCTIONS PIN DESCRIPTION NAME NO. AVDD5 1, 2, 8, 14, 18, 24, 27, 30 5-V analog supply AVDD3 9, 15, 19, 25, 28, 31 3.3-V analog supply AGND 3, 7, 10, 13, 17, 20, 23, 26, 29, Analog ground 32 DVDD3 42, 52, 63 3.3-V digital supply DGND 41, 51, 64 Digital ground NC 5, 6, 37-40 INP, INM 11, 12 CLKM, CLKP 21, 22 No connect - leave floating Differential analog inputs (P = plus = true, M = minus = complement) Differential clock inputs (P = plus = true, M = minus = complement) REF 4 Reference voltage input/output (1.2 V nominal). To use an external reference and to turn the internal reference off, pull both PDWNF and PDWNS to logic high (DVDD3). A 0.1-μF capacitor to ground on REF is recommended but not required. VCM 16 Analog input common mode, output (3.1V), for use in applications that require use of the internally generated common-mode. See the Applications section for more information on using VCM. A 0.1-μF capacitor to ground on VCM is recommended but not required. LVDSB 33 External bias resistor for LVDS bias current, normally 10 kΩ to GND to provide nominal 3.5-mA LVDS current. PDWNF 34 Light sleep power down, fast wake-up, logic high (DVDD3) = light sleep enabled (bandgap reference remains on) PDWNS 35 Deep sleep power down, slow wake-up, logic high (DVDD3) = deep sleep enabled (bandgap reference is off) DITHER 36 Dither enable, logic high (DVDD3) = dither enabled DRY_P, DRY_M 54, 53 Data ready signal (LVDS clock out) (P = plus = true, M = minus = complement) D14_15_P, D14_15_M 62, 61 DDR LVDS output bits 14 then 15 (15 is MSB) (P = plus = true, M = minus = complement) DE_O_P, DE_O_M 43-50, 55-62 DDR LVDS output bits E (even) then O (odd) (P = plus = true, M = minus = complement) D0_1_P, D0_1_M 44, 43 PowerPAD 65 DDR LVDS output bits 0 then 1 (0 is LSB) (P = plus = true, M = minus = complement) Analog ground (exposed pad on bottom of package) Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 9 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5484 - 170-MSPS Typical Data Plots in this section are with a clock of 170 MSPS, unless otherwise specified. ADS5484 SPECTRAL PERFORMANCE vs FFT for 10-MHz INPUT SIGNAL 0 −10 Amplitude − dB −60 −70 −80 −40 −50 −60 −70 −80 −90 −100 −90 −100 −110 −120 −110 −120 8.5 17 25.5 34 42.5 51 59.5 68 76.5 f − Frequency − MHz 85 0 8.5 17 34 42.5 51 59.5 68 ADS5484 SPECTRAL PERFORMANCE vs FFT for 230-MHz INPUT SIGNAL 0 −10 SFDR = 80 dBc SINAD = 74.4 dBFS SNR = 75.6 dBFS THD = 79.6 dBc Amplitude − dB −70 −80 −40 −50 −60 −70 −80 −90 −100 −90 −100 −110 −120 −110 −120 8.5 17 25.5 34 42.5 51 59.5 f − Frequency − MHz 68 76.5 SFDR = 73 dBc SINAD = 69.7 dBFS SNR = 74.9 dBFS THD = 70.3 dBc −20 −30 −60 85 0 8.5 17 25.5 34 42.5 51 59.5 f − Frequency − MHz G005 Figure 4. Submit Documentation Feedback 85 G004 ADS5484 SPECTRAL PERFORMANCE vs FFT for 130-MHz INPUT SIGNAL −40 −50 76.5 f − Frequency − MHz G003 Figure 3. −20 −30 10 25.5 Figure 2. 0 −10 0 SFDR = 87 dBc SINAD = 75.3 dBFS SNR = 75.5 dBFS THD = 87.2 dBc −20 −30 −40 −50 0 Amplitude − dB 0 −10 SFDR = 97 dBc SINAD = 76.7 dBFS SNR = 76.8 dBFS THD = 96.3 dBc −20 −30 Amplitude − dB ADS5484 SPECTRAL PERFORMANCE vs FFT for 70-MHz INPUT SIGNAL 68 76.5 85 G006 Figure 5. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5484 DIFFERENTIAL NONLINEARITY ADS5484 INTEGRAL NONLINEARITY 1.0 4 0.8 3 0.6 2 INL − LSB DNL − LSB 0.4 0.2 0.0 −0.2 −0.4 0 −1 −2 −0.6 −3 fS = 170 MSPS fIN = 10 MHz, –1 dBFS −0.8 −1.0 fS = 170 MSPS fIN = 10 MHz, –1 dBFS −4 16384 32768 49152 Code 0 65536 16384 32768 49152 65536 Code G007 G008 Figure 6. Figure 7. ADS5484 AC PERFORMANCE vs INPUT AMPLITUDE (130-MHz Input Signal) ADS5484 AC PERFORMANCE vs INPUT AMPLITUDE (130-MHz Input Signal) 130 SFDR (dBFS, 120 Dither ON) 110 SFDR (dBFS, 100 SNR (dBFS, Dither OFF) Dither ON) 90 80 70 SFDR (dBc, Dither OFF) 60 50 SFDR (dBc, 40 Dither ON) 30 fS = 170 MSPS fIN = 130 MHz 20 SNR (dBc, AIN = 0 to −100 dBFS 10 Dither ON) 256k Point FFT 0 −100 −90 −80 −70 −60 −50 −40 −30 −20 −10 0 AIN − Input Amplitude − dBFS 90 SFDR (dBc, Dither ON) 85 AC Performance − dB 0 AC Performance − dB 1 80 SFDR (dBc, Dither OFF) 75 70 fS = 170 MSPS fIN = 130 MHz AIN = 0 to −40 dBFS 256k Point FFT 65 60 −40 −36 −32 −28 −24 −20 −16 −12 G009 Figure 8. −8 −4 AIN − Input Amplitude − dBFS 0 G010 Figure 9. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 11 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5484 TWO-TONE PERFORMANCE vs INPUT AMPLITUDE (f1 = 69.5 MHz and f2 = 70.5 MHz) ADS5484 30-MHz SFDR vs AVDD5 and AVDD3 OVER TEMPERATURE −70 94 No Dither, Dominant Spur (dBFS) −90 −100 −110 −120 89 −140 87 Dither, 2F1−F2 (dBFS) −80 −70 −60 −50 −40 −30 −20 −10 Input Amplitude − dBFS AVDD5 = 4.75 V, AVDD3 = 3.15 V AVDD5 = 5 V, AVDD3 = 3.15 V 86 −40 0 AVDD5 = 5.25 V, AVDD3 = 3.15 V 90 88 Dither, 2F2−F1 (dBFS) AVDD5 = 5 V, AVDD3 = 3.45 V 91 −130 −150 −90 AVDD5 = 5.25 V, AVDD3 = 3.3 V 92 Dither, Dominant Spur (dBFS) AVDD5 = 5 V, AVDD3 = 3.3 V AVDD5 = 5.25 V, AVDD3 = 3.45 V 93 SFDR − dBc Performance − dBFS −80 AVDD5 = 4.75 V, AVDD3 = 3.45 V fS = 170 MSPS, fIN = 30 MHz −20 0 20 40 T − Temperature − °C G011 Figure 10. AVDD5 = 4.75 V, AVDD3 = 3.3 V 60 80 G012 Figure 11. ADS5484 30-MHz SNR vs AVDD5 and AVDD3 OVER TEMPERATURE 77.0 76.8 SNR − dBFS 76.6 76.4 AVDD5 = 5.25 V, AVDD3 = 3.3 V AVDD5 = 5.25 V, AVDD3 = 3.15 V AVDD5 = 5.25 V, AVDD3 = 3.45 V AVDD5 = 5 V, AVDD3 = 3.45 V AVDD5 = 4.75 V, AVDD3 = 3.45 V 76.2 76.0 75.8 75.6 75.4 75.2 75.0 −40 AVDD5 = 4.75 V, AVDD3 = 3.15 V AVDD5 = 5 V, AVDD3 = 3.3 V AVDD5 = 5 V, AVDD3 = 3.15 V fS = 170 MSPS, fIN = 30 MHz −20 AVDD5 = 4.75 V, AVDD3 = 3.3 V 0 20 40 60 80 T − Temperature − °C G013 Figure 12. 12 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5485 - 200-MSPS Typical Data Plots in this section are with a clock of 200 MSPS, unless otherwise specified. ADS5485 SPECTRAL PERFORMANCE vs FFT for 10-MHz INPUT SIGNAL 0 −10 Amplitude − dB −60 −70 −80 −40 −50 −60 −70 −80 −90 −100 −90 −100 −110 −120 −110 −120 10 20 30 40 50 60 70 80 90 f − Frequency − MHz 0 −10 0 100 20 30 40 50 60 70 80 G018 Figure 14. ADS5485 SPECTRAL PERFORMANCE vs FFT for 130-MHz INPUT SIGNAL ADS5485 SPECTRAL PERFORMANCE vs FFT for 230-MHz INPUT SIGNAL 0 −10 Amplitude − dB −70 −80 −40 −50 −60 −70 −80 −90 −100 −90 −100 −110 −120 −110 −120 10 20 30 40 50 60 70 f − Frequency − MHz 80 90 100 100 SFDR = 73 dBc SINAD = 69.5 dBFS SNR = 74.5 dBFS THD = 70.2 dBc −20 −30 −60 90 G019 Figure 13. −40 −50 0 10 f − Frequency − MHz SFDR = 84 dBc SINAD = 74.1 dBFS SNR = 75 dBFS THD = 80.8 dBc −20 −30 SFDR = 88 dBc SINAD = 74.7 dBFS SNR = 75 dBFS THD = 86 dBc −20 −30 −40 −50 0 Amplitude − dB 0 −10 SFDR = 93 dBc SINAD = 75.7 dBFS SNR = 75.8 dBFS THD = 97 dBc −20 −30 Amplitude − dB ADS5485 SPECTRAL PERFORMANCE vs FFT for 70-MHz INPUT SIGNAL 0 10 20 G020 Figure 15. 30 40 50 60 70 80 90 f − Frequency − MHz 100 G021 Figure 16. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 13 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5485 DIFFERENTIAL NONLINEARITY ADS5485 INTEGRAL NONLINEARITY 1.0 4 0.8 3 0.6 2 INL − LSB DNL − LSB 0.4 0.2 0.0 −0.2 −0.4 0 −1 −2 −0.6 −3 fS = 200 MSPS fIN = 10 MHz, –1 dBFS −0.8 −1.0 fS = 200 MSPS fIN = 10 MHz, –1 dBFS −4 16384 32768 49152 Code 0 65536 16384 49152 65536 G022 G023 Figure 17. Figure 18. ADS5485 AC PERFORMANCE vs INPUT AMPLITUDE (130-MHz Input Signal) ADS5485 AC PERFORMANCE vs INPUT AMPLITUDE (130-MHz Input Signal) 130 SNR (dBFS, 120 SFDR (dBFS, Dither ON) Dither ON) 110 SFDR (dBFS, 100 Dither OFF) 90 80 70 SFDR (dBc, Dither ON) 60 50 SFDR (dBc, 40 Dither OFF) 30 fS = 200 MSPS fIN = 130 MHz 20 SNR (dBc, AIN = 0 to −100 dBFS 10 Dither ON) 256k Point FFT 0 −100 −90 −80 −70 −60 −50 −40 −30 −20 −10 0 AIN − Input Amplitude − dBFS 90 85 fS = 200 MSPS fIN = 130 MHz AIN = 0 to −40 dBFS 256k Point FFT Submit Documentation Feedback SFDR (dBc, Dither ON) 80 SFDR (dBc, Dither OFF) 75 70 65 60 −40 −36 −32 −28 −24 −20 −16 −12 AIN − Input Amplitude − dBFS G024 Figure 19. 14 32768 Code AC Performance − dB 0 AC Performance − dB 1 −8 −4 0 G025 Figure 20. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. ADS5485 TWO-TONE PERFORMANCE vs INPUT AMPLITUDE (f1 = 69.5 MHz and f2 = 70.5 MHz) ADS5485 30-MHz SFDR vs AVDD5 and AVDD3 OVER TEMPERATURE −70 90 No Dither, Dominant Spur (dBFS) SFDR − dBc Performance − dBFS 89 Dither, Dominant Spur (dBFS) −90 −100 −110 −120 −130 −80 −70 −60 −50 −40 −30 −20 −10 87 AVDD5 = 4.75 V, AVDD3 = 3.3 V Input Amplitude − dBFS 85 −40 0 AVDD5 = 5.25 V, AVDD3 = 3.3 V AVDD5 = 5.25 V, AVDD3 = 3.15 V 88 Dither, 2F1−F2 (dBFS) −150 −90 AVDD5 = 5.25 V, AVDD3 = 3.45 V AVDD5 = 5 V, AVDD3 = 3.15 V 86 Dither, 2F2−F1 (dBFS) −140 AVDD5 = 5 V, AVDD3 = 3.3 V fS = 200 MSPS, fIN = 30 MHz −80 AVDD5 = 4.75 V, AVDD3 = 3.15 V AVDD5 = 4.75 V, AVDD3 = 3.45 V −20 AVDD5 = 5 V, AVDD3 = 3.45 V 0 20 40 60 80 T − Temperature − °C G026 Figure 21. G027 Figure 22. ADS5485 30-MHz SNR vs AVDD5 and AVDD3 OVER TEMPERATURE 76.0 75.5 AVDD5 = 5.25 V, AVDD3 = 3.3 V AVDD5 = 5.25 V, AVDD3 = 3.15 V AVDD5 = 5 V, AVDD3 = 3.3 V AVDD5 = 5.25 V, AVDD3 = 3.45 V SNR − dBFS 75.0 74.5 74.0 AVDD5 = 4.75 V, AVDD3 = 3.45 V AVDD5 = 4.75 V, AVDD3 = 3.3 V 73.5 73.0 72.5 72.0 −40 AVDD5 = 5 V, AVDD3 = 3.45 V AVDD5 = 4.75 V, AVDD3 = 3.15 V AVDD5 = 5 V, AVDD3 = 3.15 V fS = 200 MSPS, fIN = 30 MHz −20 0 20 40 60 T − Temperature − °C 80 G028 Figure 23. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 15 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. Typical Data, Valid for Both ADS5484/5485 Plots in this section are valid for either device or otherwise have combined plots. NORMALIZED GAIN RESPONSE vs INPUT FREQUENCY NOISE HISTOGRAM WITH INPUTS SHORTED 3 18 ADS5484 0 14 ADS5481 −6 ADS5485 10 8 6 2 ADS5482 G033 32706 32704 32702 32700 32698 32696 32694 32692 Output Code Figure 24. G034 Figure 25. CMRR vs COMMON-MODE INPUT FREQUENCY ADC WAKE-UP TIME 0 90 −10 80 −20 70 SNR − dBFS CMRR − dB 32690 32688 fIN − Input Frequency − Hz 32686 1G 32684 0 100M 32680 −12 10M −30 −40 −50 PDWNF 60 PDWNS 50 40 30 −60 fS = 135 MSPS fIN = 10 MHz PDWNF and PDWNS Tested Independently PDWNx Disabled at 0 ms PDWNx Enabled at ≈ 8 ms 20 −70 10 0 1 10 100 fIN − Input Frequency − MHz 1k 0 1 2 Submit Documentation Feedback 3 4 5 6 t − time − ms G054 Figure 26. 16 ADS5485 4 −9 −80 0.1 ADS5484 12 32682 −3 fs = 170 MSPS for ADS5484 fs = 200 MSPS for ADS5485 Analog Inputs Shorted to VCM 16 Percentage − % Normalized Gain Response − dB ADS5483 7 8 9 10 G066 Figure 27. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. SNR vs INPUT FREQUENCY AND SAMPLING FREQUENCY 210 200 74 75 74 75 73 75 fS - Sampling Frequency - MSPS 180 160 74 76 140 75 120 73 74 100 80 76 75 75 60 40 20 10 10 74 73 75 73 74 73 72 74 72 72 70 70 50 66 68 150 100 70 68 200 250 64 300 fIN - Input Frequency - MHz 62 64 66 68 70 72 SNR - dBFS 74 76 78 M0048-08 Figure 28. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 17 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = 25°C, sampling rate = max rated, 50% clock duty cycle, 3-VPP differential sinusoidal clock, analog input amplitude = –1 dBFS, AVDD5 = 5 V, AVDD3 = 3.3 V, and DVDD3 = 3.3 V, unless otherwise noted. SFDR vs INPUT FREQUENCY AND SAMPLING FREQUENCY 210 200 85 80 70 90 fS - Sampling Frequency - MSPS 180 75 85 160 80 140 90 120 85 100 75 80 80 70 60 40 85 90 75 80 85 20 10 10 50 150 100 65 70 60 200 250 300 fIN - Input Frequency - MHz 55 60 65 70 75 80 85 SFDR - dBc 90 95 100 M0049-08 Figure 29. 18 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 APPLICATIONS INFORMATION Theory of Operation The ADS5484/ADS5485 (ADS548x) is a 16-bit, 170/200-MSPS family of monolithic pipeline ADCs. The bipolar analog core operates from 5-V and 3.3-V supplies, while the output uses a 3.3-V supply to provide LVDS-compatible outputs. Prior to the track-and-hold, the analog input signal passes through a high-performance bipolar buffer. The buffer presents a high and consistent impedance to the analog inputs. The buffer isolates the board circuitry external to the ADC from the sampling glitches caused by the track-and-hold in the ADC. The conversion process is initiated by the falling edge of the external input clock. At that instant, the differential input signal is captured by the input track-and-hold, and the input sample is converted sequentially by a series of lower resolution stages, with the outputs combined in a digital correction logic block. Both the rising and the falling clock edges are used to propagate the sample through the pipeline every half clock cycle. This process results in a data latency of 4.5 clock cycles, after which the output data are available as a 16-bit parallel word, coded in offset binary format. Input Configuration The analog input for the ADS548x consists of an analog pseudo-differential buffer followed by a bipolar transistor T & H. The analog buffer isolates the source driving the input of the ADC from any internal switching and presents a high impedance to drive at high input frequencies, as compared to an ADC without a buffered input. The input common-mode is set internally through a 1000-Ω resistor connected from 3.1 V to each of the inputs. This configuration results in a differential input impedance of 2 kΩ at 0 Hz. Figure 30 estimates the package parasitics before soldering to a board. Each board is different, but soldering to the board will likely add 1 – 2 pF to the input capacitance. ADS548x Bipolar Transistor Buffer AVDD5 ~ 2 nH Bond Wire 10 W INP ~ 200 fF Bond Pad ~ 200 fF Package Analog Inputs 3 pF 1000 W AGND AVDD5 1000 W ~ 2 nH Bond Wire Track and Hold, VCM st 1 Pipeline Stage 3 pF AGND INM ~ 200 fF Package ~ 200 fF Bond Pad 10 W AGND Bipolar Transistor Buffer S0293-02 Figure 30. Analog Input Circuit (unsoldered package) For a full-scale differential input, each of the differential lines of the input signal (pins 11 and 12) swings symmetrically between (3.1 V + 0.75 V) and (3.1 V – 0.75 V). This range means that each input has a maximum signal swing of 1.5 VPP for a total differential input signal swing of 3 VPP. Operation below 3 VPP is allowable, with the characteristics of performance versus input amplitude demonstrated in Figure 8 through Figure 10. For instance, for performance at 2 VPP rather than 3 VPP, refer to the SNR and SFDR at –3.5 dBFS (0 dBFS = Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 19 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com 3 VPP). The maximum swing is determined by the internal reference voltage generator, eliminating the need for any external circuitry for this purpose. The primary degradation visible if the maximum amplitude is kept to 2 VPP is ~3 dBc of SNR compared to using 3 VPP, while SFDR is the same or even improved. The smaller input signal also possibly helps any components in the signal chain prior to the ADC to be more linear and provide better distortion. The ADS548x performs optimally when the analog inputs are driven differentially. The circuit in Figure 31 shows one possible configuration using an RF transformer with termination either on the primary or on the secondary of the transformer. If voltage gain is required, a step-up transformer can be used. R0 50 W Z0 50 W INP R 200 W AC Signal Source ADS548x INM n = 2:1 S0176-04 Figure 31. Converting a Single-Ended Input to a Differential Signal Using an RF Transformer Dither The ADS548x family of devices contain a dither option that is enabled via the DITHEREN pin. Dither is a technique applied to convert small static errors in the converter to dynamic errors, which look similar to white noise in the output. It improves the harmonics that are a function of the static errors. The dither is a low level and is only indicated in the output waveform as wideband noise that may slightly degrade the SNR. It is recommended that users should allow the capability to enable/disable it in the event they would like to compare the results during their evaluation. In addition to the plots on the first page of the data sheet, Figure 8 through Figure 10 and Figure 19 through Figure 21 show the minor differences of dither on/off when studied. External Voltage Reference For systems that require the analog signal gain to be adjusted or calibrated, this can be performed by using an external reference. The dependency on the signal amplitude to the value of the external reference voltage is characterized typically by Figure 32 (VREF = 1.2 V is normalized to 0 dB as this is the internal reference voltage). As can be seen in the linear fit, this equates to approximately ~1 dB of signal adjustment per 100 mV of reference adjustment. The range of allowable variation depends on the analog input amplitude that is applied to the inputs and the desired spectral performance, as can be seen in the performance versus external reference graphs in Figure 33 and Figure 34. For dc-coupled applications that use the VCM pin of the ADS548x as the common mode of the signal in the analog signal gain path prior to the ADC inputs, Figure 36 indicates little change in VCM output as VREF is externally adjusted. The VCM output is buffered with a 2-kΩ series output resistor. The method for disabling the internal reference for use with an external reference is described in Table 5 . The following VREF adjustment graphs were collected using the ADS5483, but are indicative of the behavior of the ADS5484/5485. The absolute performance may differ from device to device, but the relative characteristics are valid. 20 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 100 fS = 135 MSPS fIN = 30 MHz AIN ≤ −1 dBFS Normalized to 1.2 VREF 8 6 AIN = −2 dBFS 95 Linear Fit: y = −9.8x + 11.8 4 2 AIN = −1 dBFS 90 SFDR − dBc Normalized Gain Adjustment − dB 10 AIN = −10 dBFS 85 AIN = −4 dBFS AIN = −6 dBFS 80 0 −2 75 −4 0.5 70 0.5 fS = 135 MSPS fIN = 30 MHz Dither Enabled Signal Amplitude Relative to Adjusted Fullscale AIN = −3 dBFS AIN = −7 dBFS 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Applied External VREF − V 1.4 G057 76 AIN = −1 dBFS 1.0 1.1 1.2 1.3 1.4 G058 2.2 fS = 135 MSPS fIN = 30 MHz Signal Adjusted to −1 dBFS AIN = −6 dBFS P − Power − W SNR − dBc 0.9 2.3 AIN = −3 dBFS AIN = −2 dBFS AIN = −4 dBFS 78 AIN = −7 dBFS 70 68 66 64 62 60 0.5 0.8 Figure 33. SFDR versus External VREF and AIN 80 72 0.7 Applied External VREF − V Figure 32. Signal Gain Adjustment versus External Reference (VREF) 74 0.6 AIN = −10 dBFS 0.6 0.7 0.8 0.9 1.0 2.1 2.0 1.9 fS = 135 MSPS fIN = 30 MHz Dither Enabled Signal Amplitude Relative to Adjusted Fullscale 1.1 1.2 1.3 Applied External VREF − V 1.8 1.7 0.5 1.4 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Applied External VREF − V G059 Figure 34. SNR versus External VREF and AIN 1.4 G060 Figure 35. Total Power Consumption versus External VREF 3.20 VCM Pin Output Voltage − V 3.19 3.18 3.17 3.16 3.15 3.14 3.13 3.12 3.11 3.10 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Applied External VREF − V 1.4 G061 Figure 36. VCM Pin Output versus External VREF Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 21 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com Clock Inputs The ADS548x equivalent clock input circuit is shown in Figure 37. The clock inputs can be driven with either a differential clock signal or a single-ended clock input, but differential is highly recommended. The characterization of the ADS548x is typically performed with a 3-VPP differential clock, but the ADC performs well with a differential clock amplitude down to ~1 VPP, as shown in Figure 39 and Figure 40 . The performance is optimized when the clock amplitude is kept above 2 VPP. The clock amplitude becomes more of a factor in performance as the analog input frequency increases. When single-ended clocking is a necessity, it is best to connect CLKM to ground with a 0.01-μF capacitor, while CLKP is ac-coupled with a 0.01-μF capacitor to the clock source, as shown in Figure 38. Figure 37. Clock Input Circuit Square Wave or Sine Wave CLKP 0.01 mF ADS548x CLKM 0.01 mF S0168-08 Figure 38. Single-Ended Clock 22 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 SFDR vs CLOCK AMPLITUDE SNR vs CLOCK AMPLITUDE 110 81 fIN = 100.33 MHz fIN = 9.97 MHz fIN = 30.13 MHz fIN = 30.13 MHz 79 100 fIN = 9.97 MHz fIN = 69.59 MHz SNR − dBFS SFDR − dBc 77 90 80 70 73 fIN = 130.13 MHz 71 fIN = 170.13 MHz fIN = 69.59 MHz fIN = 100.33 MHz 69 fIN = 130.13 MHz 60 75 67 fIN = 170.13 MHz fS = 170 MSPS 50 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Clock Amplitude − VPP 4.5 5.0 65 0.0 0.5 1.0 1.5 fS = 170 MSPS 2.0 2.5 3.0 3.5 4.0 4.5 Clock Amplitude − VPP G035 Figure 39. 5.0 G036 Figure 40. For jitter-sensitive applications, the use of a differential clock has some advantages at the system level. The differential clock allows for common-mode noise rejection at the printed circuit board (PCB) level. With a differential clock, the signal-to-noise ratio of the ADC is better for jitter-sensitive, high-frequency applications because the board level clock jitter is superior. The sampling process is more sensitive to jitter using high analog input frequencies or slow clock frequencies. Large clock amplitude levels are recommended when possible to reduce the indecision (jitter) in the ADC clock input buffer. Whenever possible, the ideal combination is a differential clock with large signal swing (~1 – 3 VPP). Figure 41 demonstrates a recommended method for converting a single-ended clock source into a differential clock; it is similar to the configuration found on the evaluation board and was used for much of the characterization. See also Clocking High Speed Data Converters (SLYT075) for more details. Clock Source 0.1 mF CLKP ADS548x CLKM S0194-03 Figure 41. Differential Clock The common-mode voltage of the clock inputs is set internally to ~2 V using internal 0.5-kΩ resistors. It is recommended to use ac coupling, but if this scheme is not possible, the ADS548x features good tolerance to clock common-mode variation (as shown in Figure 42 and Figure 43). The internal ADC core uses both edges of the clock for the conversion process. Ideally, a 50% duty-cycle clock signal should be provided. Performance degradation as a result of duty cycle can be seen in Figure 44. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 23 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com 100 76 30.13 MHz 75 69.59 MHz 74 SNR − dBFS SFDR − dBc 90 80 70 100.33 MHz 1.0 1.5 71 30.13 MHz 69.59 MHz 70 68 67 CLK = 200 MSPS 50 0.5 230.53 MHz 72 69 230.53 MHz 60 73 2.0 2.5 3.0 3.5 Clock Common-Mode Voltage − V 100.33 MHz CLK = 200 MSPS 66 0.5 1.0 1.5 2.0 2.5 3.0 Clock Common-Mode Voltage − V G037 Figure 42. SFDR versus Clock Common-Mode Voltage 3.5 G038 Figure 43. SNR versus Clock Common-Mode Voltage 95 30 MHz 90 SFDR − dBc 85 80 75 70 130 MHz 65 230 MHz 60 170 MSPS (ADS5484) 200 MSPS (ADS5485) 55 50 30 35 40 45 50 55 60 65 Clock Duty Cycle − % 70 G039 Figure 44. SFDR vs Clock Duty Cycle The ADS5484 is capable of achieving 75.7 dBFS SNR at 130 MHz of analog input frequency. In order to achieve the SNR at 130 MHz the clock source rms jitter (at the ADC clock input pins) must be at most 184 fsec in order for the total rms jitter to be 201 fsec due to internal ADC aperture jitter of ~80 fsec. A summary of maximum recommended rms clock jitter as a function of analog input frequency for the ADS5484 is provided in Table 3. The equations used to create the table are presented and can be used to estimate required clock jitter for virtually any pipeline ADC, but in particular, the ADS5481/5482/5483/5484/5485 family. Table 3. Recommended Approximate RMS Clock Jitter for ADS5484 ANALOG INPUT FREQUENCY (MHz) 24 MEASURED SNR (dBc) TOTAL JITTER (fsec rms) MAXIMUM CLOCK JITTER (fsec rms) 10 76.8 2301 2299 30 75.9 851 847 70 75.7 373 364 130 75.7 201 184 170 75.6 155 133 230 74.9 124 95 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 Equation 1 and Equation 2 are used to estimate the required clock source jitter. SNR (dBc) = -20 ´ LOG10 (2 ´ p ´ fIN ´ jTOTAL) 2 (1) 2 1/2 jTOTAL = (jADC + jCLOCK ) (2) where: jTOTAL = the rms summation of the clock and ADC aperture jitter; jADC = the ADC internal aperture jitter which is located in the data sheet; jCLOCK = the rms jitter of the clock at the clock input pins to the ADC; and fIN = the analog input frequency. Notice that the SNR is a strong function of the analog input frequency, not the clock frequency. The slope of the clock source edges can have a mild impact on SNR as well and is not taken into account for these estimates. For this reason, maximizing clock source amplitudes at the ADC clock inputs is recommended, though not required (faster slope is desirable for jitter-related SNR). For more information on clocking high-speed ADCs, see Application Note SLWA034, Implementing a CDC7005 Low Jitter Clock Solution For High-Speed, High-IF ADC Devices, on the Texas Instruments web site. Recommended clock distribution chips (CDCs) are the TI CDCE72010 and CDCM7005. Depending on the jitter requirements, a band pass filter (BPF) is sometimes required between the CDC and the ADC. If the insertion loss of the BPF causes the clock amplitude to be too low for the ADC, or the clock source amplitude is too low to begin with, an inexpensive amplifier can be placed between the CDC and the BPF, as its harmonics and wide-band noise are reduced by the BPF. Figure 45 represents a scenario where an LVCMOS single-ended clock output is used from a TI CDCE72010 with the clock signal path optimized for maximum amplitude and minimum jitter. The jitter of this setup is difficult to estimate and requires a careful phase noise analysis of the clock path. The BPF (and possibly a low-cost amplifier because of insertion loss in the BPF) can improve the jitter between the CDC and ADC when the jitter provided by the CDC is still not adequate. The total jitter at the CDCE72010 output depends largely on the phase noise of the VCXO/VCO selected, as well as from the CDCE72010 itself. Board Master Reference Clock (High or Low Jitter) 10 MHz AMP and/or BPF Optional REF LVCMOS 100 MHz AMP BPF XFMR 400 MHz (To Transmit DAC) CLKP CLKM ADC TI ADS548x 100 MHz (To DSP) Low Jitter Oscillator LVPECL or LVCMOS 100 MHz (To FPGA) 400 MHz VCO/ VCXO CDC (Clock Distribution Chip) Ex: TI CDCE72010 To Other B0268-01 Consult the CDCE72010 data sheet for proper schematic and specifications regarding allowable input and output frequency and amplitude ranges. Figure 45. Optimum Jitter Clock Circuit Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 25 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com Digital Outputs The ADC provides eight LVDS-compatible, offset binary, DDR data outputs (2 bits per LVDS output driver) and a data-ready LVDS signal (DRY). It is recommended to use the DRY signal to capture the output data of the ADS548x (use as a clock output). DRY is source-synchronous to the DATA outputs and operates at the same frequency, creating a full-rate DDR interface that updates data on both the rising and falling edges of DRY. It is recommended that the capacitive loading on the digital outputs be minimized. Higher capacitance shortens the data-valid timing window. The values given for timing (see Figure 1) were obtained with a 5-pF parasitic board capacitance to ground on each LVDS line. When setting the time relationship between DRY and DATA at the receiving device, it is generally recommended that setup time be maximized, but this partially depends on the setup and hold times of the device receiving the digital data. Since DRY and DATA are coincident, it will likely be necessary to delay either DRY such that DATA setup time is maximized. The LVDS outputs all require an external 100-Ω load between each output pair in order to meet the expected LVDS voltage levels. For long trace lengths, it may be necessary to place a 100-Ω load on each digital output as close to the ADS548x as possible and another 100-Ω differential load at the end of the LVDS transmission line to terminate the transmission line and avoid signal reflections. The effective load in this case reduces the LVDS voltage levels by half. The current of all LVDS drivers is set externally with a resistor connected between the LVDSB (LVDS bias) pin and ground. Normal LVDS current is 3.5 mA per LVDS pair, set with a 10-kΩ external resistor. For systems with excessive load capacitance on the LVDS lines, reducing the resistor value in order to increase the LVDS bias current is allowed to create a stronger LVDS drive capability. For systems with short traces and minimal loading, increasing the resistor in order to decrease the LVDS current is allowable in order to save power. Table 4 provides a sampling of LVDSB resistor values should deviation from the recommended LVDS output current of 3.5 mA be considered. It is not recommended to exceed the range listed in the table. If the LVDS bias current is adjusted, the differential load resistance should also be adjusted to maintain voltage levels within the specification for the LVDS outputs. The signal integrity of the LVDS lines on the board layout should be scrutinized to ensure proper LVDS signal integrity exists. Table 4. Setting the LVDS Current Drive 26 LVDSB RESISTOR TO GND, Ω LVDS NOMINAL CURRENT, mA 6k 5.6 8k 4.3 10k (value for normal recommended operation) 3.5 12k 2.8 14k 2.3 16k 2.0 18k 1.7 20k 1.5 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 Power Supplies and Sleep Modes The ADS548x uses three power supplies. For the analog portion of the design, a 5-V and 3.3-V supply (AVDD5 and AVDD3) are used, while the digital portion uses a 3.3-V supply (DVDD3). The use of low-noise power supplies with adequate decoupling is recommended. Linear supplies are preferred to switched supplies; switched supplies generate more noise that can be coupled to the ADS548x. However, the PSRR value and plot shown in Figure 46 were obtained without bulk supply decoupling capacitors. When bulk (0.1-μF) decoupling capacitors are used near the supply pins, the board-level PSRR is much higher than the stated value for the ADC. The user may be able to supply power to the device with a less-than-ideal supply and still achieve good performance. It is not possible to make a single recommendation for every type of supply and level of decoupling for all systems. If the noise characteristics of the available supplies are understood, a study of the PSRR data for the ADS548x may provide the user with enough information to select noisy supplies if the performance is still acceptable within the frequency range of interest. The power consumption of the ADS548x does not change substantially over clock rate or input frequency. 0 PSRR − dB −20 −40 AVDD3V −60 AVDD5V −80 −100 DVDD3V −120 0.1 1 10 100 fIN − Input Frequency − MHz 1k G067 Figure 46. PSRR versus Supply Injected Frequency Two separate sleep modes are offered. They are differentiated by the amount of power consumed and the time it takes for the ADC to wake-up from sleep. The light sleep mode consumes 605 mW and can be used when wake-up of less than 600 μs is required. Deep sleep consumes 70 mW and requires 6 ms to wake-up. See the wake-up characteristic in Figure 27. For directions on enabling these modes, see Table 5. The input clock can be in either state when the power-down modes are enabled. The device can enter power-down mode whether using an internal or external reference. However, the wake-up time from light sleep enabled to external reference mode is dependent on the external reference voltage and is not necessarily 0.6 ms, but should be noticeably faster than deep sleep wake-up. No specific power sequences are required. Table 5. Power-Down and Reference Modes MODE PDWNF PIN PDWNS PIN POWER CONSUMPTION WAKE-UP TIME On ADC On - Internal reference Low Low 2.16 W ADC On - External reference High High 2.16 W On Light sleep High Low 600 mW when enabled 0.6 ms Deep sleep Low High 70 mW when enabled 6 ms Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 27 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com Layout Information The evaluation board represents a good model of how to lay out the printed circuit board (PCB) to obtain the maximum performance from the ADS548x. Follow general design rules, such as the use of multilayer boards, a single ground plane for ADC ground connections, and local decoupling ceramic chip capacitors. The analog input traces should be isolated from any external source of interference or noise, including the digital outputs as well as the clock traces. The clock signal traces should also be isolated from other signals, especially in applications such as high IF sampling where low jitter is required. Besides performance-oriented rules, care must be taken when considering the heat dissipation of the device. The thermal heat sink included on the bottom of the package should be soldered to the board as described in the PowerPad Package section. See the ADS548x EVM User Guide on the TI web site for the evaluation board schematic. PowerPAD Package The PowerPAD package is a thermally-enhanced, standard-size IC package designed to eliminate the use of bulky heat sink and slugs traditionally used in thermal packages. This package can be easily mounted using standard PCB assembly techniques and can be removed and replaced using standard repair procedures. The PowerPAD package is designed so that the leadframe die pad (or thermal pad) is exposed on the bottom of the IC. This pad design provides an extremely low thermal resistance path between the die and the exterior of the package. The thermal pad on the bottom of the IC can then be soldered directly to the PCB, using the PCB as a heat sink. Assembly Process 1. Prepare the PCB top-side etch pattern including etch for the leads as well as the thermal pad as illustrated in the Mechanical Data section (at the end of this data sheet). 2. Place a 6-by-6 array of thermal vias in the thermal pad area. These holes should be 13 mils (0.013 in or 0.3302 mm) in diameter. The small size prevents wicking of the solder through the holes. 3. It is recommended to place a small number of 25 mil (0.025 in or 0.635 mm) diameter holes under the package, but outside the thermal pad area, to provide an additional heat path. 4. Connect all holes (both those inside and outside the thermal pad area) to an internal copper plane (such as a ground plane). 5. Do not use the typical web or spoke via-connection pattern when connecting the thermal vias to the ground plane. The spoke pattern increases the thermal resistance to the ground plane. 6. The top-side solder mask should leave exposed the terminals of the package and the thermal pad area. 7. Cover the entire bottom side of the PowerPAD vias to prevent solder wicking. 8. Apply solder paste to the exposed thermal pad area and all of the package terminals. For more detailed information regarding the PowerPAD package and its thermal properties, see either the PowerPAD Made Easy application brief (SLMA004) or the PowerPAD Thermally Enhanced Package application report (SLMA002), both available for download at www.ti.com. 28 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 ADS5484 ADS5485 www.ti.com ............................................................................................................................................... SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 DEFINITION OF SPECIFICATIONS Analog Bandwidth The analog input frequency at which the power of the fundamental is reduced by 3 dB with respect to the low-frequency value. The injected frequency level is translated into dBFS, the spur in the output FFT is measured in dBFS, and the difference is the PSRR in dB. The measurement calibrates out the benefit of the board supply decoupling capacitors. Aperture Uncertainty (Jitter) The sample-to-sample variation in aperture delay. Signal-to-Noise Ratio (SNR) SNR is the ratio of the power of the fundamental (PS) to the noise floor power (PN), excluding the power at dc and in the first five harmonics. P SNR + 10log 10 S PN Clock Pulse Duration/Duty Cycle The duty cycle of a clock signal is the ratio of the time the clock signal remains at a logic high (clock pulse duration) to the period of the clock signal, expressed as a percentage. SNR is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the reference, or dBFS (dB to full-scale) when the power of the fundamental is extrapolated to the converter full-scale range. Differential Nonlinearity (DNL) An ideal ADC exhibits code transitions at analog input values spaced exactly 1 LSB apart. DNL is the deviation of any single step from this ideal value, measured in units of LSB. Signal-to-Noise and Distortion (SINAD) SINAD is the ratio of the power of the fundamental (PS) to the power of all the other spectral components including noise (PN) and distortion (PD), but excluding dc. PS SINAD + 10log 10 PN ) PD Aperture Delay The delay in time between the rising edge of the input sampling clock and the actual time at which the sampling occurs. Common-Mode Rejection Ratio (CMRR) CMRR measures the ability to reject signals that are presented to both analog inputs simultaneously. The injected common-mode frequency level is translated into dBFS, the spur in the output FFT is measured in dBFS, and the difference is the CMRR in dB. Effective Number of Bits (ENOB) ENOB is a measure in units of bits of converter performance as compared to the theoretical limit based on quantization noise: ENOB = (SINAD – 1.76)/6.02 Gain Error Gain error is the deviation of the ADC actual input full-scale range from its ideal value, given as a percentage of the ideal input full-scale range. Integral Nonlinearity (INL) INL is the deviation of the ADC transfer function from a best-fit line determined by a least-squares curve fit of that transfer function. The INL at each analog input value is the difference between the actual transfer function and this best-fit line, measured in units of LSB. Offset Error Offset error is the deviation of output code from mid-code when both inputs are tied to common-mode. Power-Supply Rejection Ratio (PSRR) PSRR is a measure of the ability to reject frequencies present on the power supply. (4) (5) SINAD is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the reference, or dBFS (dB to full-scale) when the power of the fundamental is extrapolated to the converter full-scale range. Temperature Drift Temperature drift (with respect to gain error and offset error) specifies the change from the value at the nominal temperature to the value at TMIN or TMAX. It is computed as the maximum variation the parameters over the whole temperature range divided by TMIN – TMAX. Total Harmonic Distortion (THD) THD is the ratio of the power of the fundamental (PS) to the power of the first five harmonics (PD). P THD + 10log 10 S PD (6) THD is typically given in units of dBc (dB to carrier). Two-Tone Intermodulation Distortion (IMD3) IMD3 is the ratio of the power of the fundamental (at frequencies f1, f2) to the power of the worst spectral component at either frequency 2f1 – f2 or 2f2 – f1). IMD3 is given in units of either dBc (dB to carrier) when the absolute power of the fundamental is used as the reference, or dBFS (dB to full-scale) when the power of the fundamental is extrapolated to the converter full-scale range. Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 Submit Documentation Feedback 29 ADS5484 ADS5485 SLAS610C – AUGUST 2008 – REVISED OCTOBER 2009 ............................................................................................................................................... www.ti.com REVISION HISTORY Changes from Revision B (July 2009) to Revision C ..................................................................................................... Page • Changed pin PDWNF from 35 to 34 ..................................................................................................................................... 9 • Changed pin PDWNS from 34 to 35 ..................................................................................................................................... 9 30 Submit Documentation Feedback Copyright © 2008–2009, Texas Instruments Incorporated Product Folder Link(s): ADS5484 ADS5485 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) ADS5484IRGCT ACTIVE VQFN RGC 64 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ5484 ADS5485IRGCR ACTIVE VQFN RGC 64 2000 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ5485 ADS5485IRGCT ACTIVE VQFN RGC 64 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ5485 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
ADS5485IRGCT 价格&库存

很抱歉,暂时无法提供与“ADS5485IRGCT”相匹配的价格&库存,您可以联系我们找货

免费人工找货