ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 13-BIT 250 MSPS ANALOG-TO-DIGITAL CONVERTER FEATURES APPLICATIONS • • • • • • • • • • • • • • • • • • • • 13-Bit Resolution 250 MSPS Sample Rate SNR = 69 dBc at 100-MHz IF and 250 MSPS SFDR = 76 dBc at 100-MHz IF and 250 MSPS SNR = 67.7 dBc at 230-MHz IF and 250 MSPS SFDR = 77 dBc at 230-MHz IF and 250 MSPS 2.2 VPP Differential Input Voltage Fully Buffered Analog Inputs 5 V Analog Supply Voltage LVDS Compatible Outputs Total Power Dissipation: 2 W Offset Binary Output Format TQFP-80 PowerPAD™ Package Pin Compatible with the ADS5440 Industrial Temperature Range = –40°C to 85°C Test and Measurement Software-Defined Radio Multi-channel Basestation Receivers Basestation Tx Digital Predistortion Communications Instrumentation RELATED PRODUCTS • • • ADS5424 - 14-bit, 105 MSPS ADC ADS5423 - 14-bit, 80 MSPS ADC ADS5440 - 13-bit, 210 MSPS ADC DESCRIPTION The ADS5444 is a 13-bit 250 MSPS analog-to-digital converter (ADC) that operates from a 5 V supply, while providing LVDS-compatible digital outputs from a 3.3 V supply. The ADS5444 input buffer isolates the internal switching of the onboard track and hold (T&H) from disturbing the signal source. An internal reference generator is also provided to further simplify the system design. The ADS5444 has outstanding low noise and linearity over input frequency. AVDD AIN AIN A1 TH1 + TH2 Σ A2 + TH3 ADC1 DAC1 Reference A3 ADC3 − − VREF Σ DVDD ADC2 5 DAC2 5 5 Digital Error Correction CLK CLK Timing OVR OVR DRY DRY D[12:0] GND B0061-01 The ADS5444 is available in an 80-pin TQFP PowerPAD™ package. The ADS5444 is built on a state of the art Texas Instruments complementary bipolar process (BiCom3X) and is specified over the full industrial temperature range (–40°C to 85°C). 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. 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 © 2005–2006, Texas Instruments Incorporated ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 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. PACKAGING/ORDERING INFORMATION (1) Product ADS5444 (1) (2) PackageLead Package Designator HTQFP-80 (2) PowerPAD (1) PFP Specified Temperature Range Package Marking –40°C to 85°C ADS5444IPFP Ordering Number Transport Media, Quantity ADS5444IPFP Tray, 96 ADS5444IPFPR Tape and Reel, 1000 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. Thermal pad size: 7,5 mm x 7,5 mm (typ) ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VALUE / UNIT Supply voltage AVDD to GND 6V DRVDD to GND 5V Analog input to GND –0.3 V to AVDD+0.3 V Clock input to GND –0.3 V to AVDD+0.3 V CLK to CLK ±2.5 V Digital data output to GND –0.3 V to DRVDD+0.3 V Operating temperature range –40°C to 85°C Maximum junction temperature 150°C Storage temperature range –65°C to 150°C ESD Human Body Model (HBM) (1) 2.5 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. THERMAL CHARACTERISTICS (1) PARAMETER θJA θJC (1) 2 TEST CONDITIONS TYP UNIT Soldered slug, no airflow 21.7 °C/W Soldered slug, 250-LFPM airflow 15.4 °C/W 50 °C/W Unsoldered slug, 250-LFPM airflow 43.4 °C/W Bottom of package (heatslug) 2.99 °C/W Unsoldered slug, no airflow Using 36 thermal vias (6 x 6 array). See the Application Section. Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 RECOMMENDED OPERATING CONDITIONS MIN NOM MAX UNIT 4.75 5 5.25 V 3 3.3 3.6 V SUPPLIES AVDD Analog supply voltage DRVDD Output driver supply voltage ANALOG INPUT VCM Differential input range 2.2 VPP Input common mode 2.4 V CLOCK INPUT 1/tC ADCLK input sample rate (sine wave) 10 250 Clock amplitude, differential sine wave Clock duty cycle TA MSPS 3 Vpp 50% Open free air temperature –40 85 °C ELECTRICAL CHARACTERISTICS MIN, TYP, and MAX values at TA = 25°C, full temperature range is TMIN = –40°C to TMAX = 85°C, sampling rate = 250 MSPS, 50% clock duty cycle, AVDD = 5 V, DRVDD = 3.3 V, –1 dBFS differential input, and 3 VPP differential clock, unless otherwise noted PARAMETER TEST CONDITIONS MIN Resolution TYP MAX UNIT 13 Bits 2.2 Vpp 1 kΩ ANALOG INPUTS Differential input range Differential input resistance (DC) Differential input capacitance 1.5 pF Analog input bandwidth 800 MHz 2.4 V INTERNAL REFERENCE VOLTAGE VREF Reference voltage DYNAMIC ACCURACY No missing codes Assured DNL Differential linearity error fIN = 10 MHz -1 ±0.4 1 LSB INL Integral linearity error fIN = 10 MHz -2.2 ±0.9 2.2 LSB Offset error -11 Offset temperature coefficient 0.0005 Gain error –5 Gain temperature coefficient PSRR 11 100-MHz supply frequency mV mV/°C 5 %FS -0.02 ∆%/°C 1 mV/V POWER SUPPLY IAVDD Analog supply current IDRVDD Output buffer supply current VIN = full scale, fIN = 100 MHz, FS = 250 MSPS Power dissipation Submit Documentation Feedback 340 390 mA 80 100 mA 2 2.28 W 3 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 ELECTRICAL CHARACTERISTICS (continued) MIN, TYP, and MAX values at TA = 25°C, full temperature range is TMIN = –40°C to TMAX = 85°C, sampling rate = 250 MSPS, 50% clock duty cycle, AVDD = 5 V, DRVDD = 3.3 V, –1 dBFS differential input, and 3 VPP differential clock, unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DYNAMIC AC CHARACTERISTICS fIN = 10 MHz 69.3 fIN = 70 MHz 69 fIN = 100 MHz SNR Signal-to-noise ratio TA = 25°C Full Temp Range 67 66.5 68.3 fIN = 230 MHz 67.7 fIN = 300 MHz 67 fIN = 400 MHz 66 fIN = 10 MHz 85 fIN = 100 MHz HD2 HD3 Spurious free dynamic range Second harmonic Third harmonic Worst other harmonic/spur (other than HD2 and HD3) 4 69 fIN = 170 MHz fIN = 70 MHz SFDR 69 dBc 77 TA = 25°C 70 77 Full Temp Range 68 77 fIN = 170 MHz 74 fIN = 230 MHz 77 fIN = 300 MHz 70 fIN = 400 MHz 64 fIN = 10 MHz 87 fIN = 70 MHz 77 fIN = 100 MHz 80 fIN = 170 MHz 74 fIN = 230 MHz 78 fIN = 300 MHz 70 fIN = 400 MHz 64 fIN = 10 MHz 86 fIN = 70 MHz 82 fIN = 100 MHz 79 fIN = 170 MHz 80 fIN = 230 MHz 91 fIN = 300 MHz 80 fIN = 400 MHz 69 fIN = 10 MHz 90 fIN = 70 MHz 95 fIN = 100 MHz 82 fIN = 170 MHz 80 fIN = 230 MHz 83 fIN = 300 MHz 86 fIN = 400 MHz 85 Submit Documentation Feedback dBc dBc dBc dBc ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 ELECTRICAL CHARACTERISTICS (continued) MIN, TYP, and MAX values at TA = 25°C, full temperature range is TMIN = –40°C to TMAX = 85°C, sampling rate = 250 MSPS, 50% clock duty cycle, AVDD = 5 V, DRVDD = 3.3 V, –1 dBFS differential input, and 3 VPP differential clock, unless otherwise noted PARAMETER TEST CONDITIONS MIN fIN = 10 MHz 67.6 fIN = 170 MHz 66.5 fIN = 230 MHz 67 fIN = 300 MHz 65 Effective number of bits fIN = 10 MHz RMS idle channel noise Inputs tied to common-mode UNIT 68 fIN = 100 MHz fIN = 400 MHz ENOB MAX 69 fIN = 70 MHz SINAD TYP dBc 61 11.2 Bits 0.4 LSB DIGITAL CHARACTERISTICS – LVDS DIGITAL OUTPUTS Differential output voltage 0.247 Output offset voltage 1.125 Submit Documentation Feedback 1.25 0.452 V 1.375 V 5 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TIMING CHARACTERISTICS tA N+3 N AIN N+1 N+2 tCLK CLK, CLK tCLKH N+1 N N+4 tCLKL N+2 N+3 N+4 tC_DR D[12:0], OVR, OVR N−3 tr N−2 tf tsu_c N−1 th_c N th_DR tsu_DR DRY, DRY tDR T0073-01 Figure 1. Timing Diagram TIMING CHARACTERISTICS Min, Typ, Max over full temperature range, 50% clock duty cycle, sampling rate = 250 MSPS, AVDD = 5 V, DRVDD = 3.3 V PARAMETER TEST CONDITIONS MIN TYP MAX UNIT tA Aperature delay 500 ps tJ Clock slope independent aperture uncertainty (jitter) 200 fs RMS Latency 4 cycles tCLK Clock period 4 ns tCLKH Clock pulsewidth high 2 ns tCLKL Clock pulsewidth low 2 ns Clock Input Clock to DataReady (DRY) tDR Clock rising to DataReady falling tC_DR Clock rising to DataReady rising 1.1 Clock duty cycle = 50% (1) 2.7 3.1 ns 3.5 ns Clock to DATA, OVR (2) tr Data rise time (20% to 80%) 0.6 ns tf Data fall time(80% to 20%) 0.6 ns tsu_c Data valid to clock (setup time) 3.1 ns th_c Clock to invalid Data (hold time) 0.2 ns DataReady (DRY)/DATA, OVR (2) tsu(DR) Data valid to DRY 1.7 2 ns th(DR) DRY to invalid Data 0.9 1.3 ns (1) (2) 6 tC_DR = tDR + tCLKH for clock duty cycles other than 50% Data is updated with clock falling edge or DRY rising edge. Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 DEVICE INFORMATION PFP PACKAGE (TOP VIEW) D5 D5 D6 D6 GND DVDD D7 D7 D8 D8 D9 D9 D10 D10 D11 D11 D12 D12 DRY DRY 61 39 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 1 2 3 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 4 5 6 GND 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 7 8 9 10 11 12 13 14 15 16 17 18 19 20 DVDD GND AVDD NC NC VREF GND AVDD GND CLK CLK GND AVDD AVDD GND AIN AIN GND AVDD GND D4 D4 D3 D3 D2 D2 D1 D1 GND DVDD D0 D0 NC NC NC NC NC NC OVR OVR GND AVDD GND AVDD GND AVDD GND NC GND AVDD GND NC GND AVDD GND AVDD GND AVDD GND AVDD P0027-01 TERMINAL FUNCTIONS TERMINAL NAME AVDD DVDD GND NO. DESCRIPTION 3, 8, 13, 14, 19, 21, 23, 25, 27, 31, 35, 37, Analog power supply 39 1, 51, 66 Output driver power supply 2, 7, 9, 12, 15, 18, 20, 22, 24, 26, 28, 30, 32, Ground 34, 36, 38, 40, 52, 65 VREF 6 Reference voltage CLK 10 Differential input clock (positive). Conversion initiated on rising edge CLK 11 Differential input clock (negative) AIN 16 Differential input signal (positive) AIN 17 Differential input signal (negative) Submit Documentation Feedback 7 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 DEVICE INFORMATION (continued) TERMINAL FUNCTIONS (continued) TERMINAL NAME NO. DESCRIPTION OVR, OVR 42, 41 Over range indicator LVDS output. A logic high signals an analog input in excess of the full-scale range. D0, D0 50, 49 LVDS digital output pair, least-significant bit (LSB) D1–D6, D1–D6 53–64 LVDS digital output pairs D7–D11, D7–D11 67–76 LVDS digital output pairs D12, D12 78, 77 LVDS digital output pair, most-significant bit (MSB) DRY, DRY 80, 79 Data ready LVDS output pair NC 4, 5, 29, 33, 43–48 No connect 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. Aperture Delay The delay in time between the rising edge of the input sampling clock and the actual time at which the sampling occurs. Aperture Uncertainty (Jitter) The sample-to-sample variation in aperture delay. Clock Pulse Width/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 width) to the period of the clock signal. Duty cycle is typically expressed as a percentage. A perfect differential sine wave clock results in a 50% duty cycle. Maximum Conversion Rate The maximum sampling rate at which certified operation is given. All parametric testing is performed at this sampling rate unless otherwise noted. Minimum Conversion Rate The minimum sampling rate at which the ADC functions. Differential Nonlinearity (DNL) An ideal ADC exhibits code transitions at analog input values spaced exactly 1 LSB apart. The DNL is the deviation of any single step from this ideal value, measured in units of LSB. Integral Nonlinearity (INL) The INL is the deviation of the ADCs 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. Gain Error The gain error is the deviation of the ADCs actual input full-scale range from its ideal value. The gain error is given as a percentage of the ideal input full-scale range. Offset Error Offset error is the deviation of output code from mid-code when both inputs are tied to common-mode. 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. 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 the first five harmonics. P SNR 10log S 10 P N (1) 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’s full-scale range. 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. P SINAD 10log S 10 P P N D (2) 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’s full-scale range. 8 Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 DEFINITION OF SPECIFICATIONS (continued) Effective Resolution Bandwidth The highest input frequency where the SNR (dB) is dropped by 3 dB for a full-scale input amplitude. Total Harmonic Distortion (THD) THD is the ratio of the power of the fundamental (PS) to the power of the first five harmonics (PD). THD 10log P S 10 P D (3) THD is typically given in units of dBc (dB to carrier). Two-Tone Intermodulation Distortion 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 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’s full-scale range. Submit Documentation Feedback 9 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS Spectral Performance (FFT For 10 MHz Input Signal) Spectral Performance (FFT For 100 MHz Input Signal) 0 0 SFDR = 86.8 dBc SNR = 68.7 dBc THD = 82.3 dBc SINAD = 68.5 dBc −20 −40 Amplitude − dB Amplitude − dB −20 SFDR = 76.1 dBc SNR = 69 dBc THD = 72.6 dBc SINAD = 67.4 dBc −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G001 G002 Figure 2. Figure 3. Spectral Performance (FFT For 170 MHz Input Signal) Spectral Performance (FFT For 230 MHz Input Signal) 0 0 SFDR = 74.6 dBc SNR = 68.4 dBc THD = 72.5 dBc SINAD = 67 dBc −20 −40 Amplitude − dB Amplitude − dB −20 SFDR = 77 dBc SNR = 67.3 dBc THD = 75.6 dBc SINAD = 66.7 dBc −60 −80 −40 −60 −80 −100 −100 −120 −120 0 0 10 20 30 40 50 60 70 80 90 100 110 120 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G004 G003 Figure 4. 10 Figure 5. Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Spectral Performance (FFT For 300 MHz Input Signal) Spectral Performance (FFT For 400 MHz Input Signal) 0 0 SFDR = 70.2 dBc SNR = 67 dBc THD = 69.5 dBc SINAD = 65 dBc −20 −40 Amplitude − dB Amplitude − dB −20 SFDR = 62.5 dBc SNR = 66.2 dBc THD = 61.8 dBc SINAD = 60.4 dBc −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G005 G006 Figure 6. Figure 7. Two-Tone Intermodulation Distortion (FFT For 51.5 MHz and 52.5 MHz Input Signals) Two-Tone Intermodulation Distortion (FFT For 51.5 MHz and 52.5 MHz Input Signals) 0 0 FIN1 = 51.5 MHz, −7 dBFS FIN2 = 52.5 MHz, −7 dBFS IMD3 = 100.6 dBFS −20 −40 Amplitude − dB Amplitude − dB −20 FIN1 = 51.5 MHz, −16 dBFS FIN2 = 52.5 MHz, −16 dBFS IMD3 = 99.6 dBFS −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G007 Figure 8. G008 Figure 9. Submit Documentation Feedback 11 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Two-Tone Intermodulation Distortion (FFT For 151 MHz and 152 MHz Input Signals) Two-Tone Intermodulation Distortion (FFT For 151 MHz and 152 MHz Input Signals) 0 0 FIN1 = 151 MHz, −7 dBFS FIN2 = 152 MHz, −7 dBFS IMD3 = 89.4 dBFS −20 −40 Amplitude − dB Amplitude − dB −20 FIN1 = 151 MHz, −16 dBFS FIN2 = 152 MHz, −16 dBFS IMD3 = 92.5 dBFS −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G009 G010 Figure 10. Figure 11. Two-Tone Intermodulation Distortion (FFT For 229 MHz and 230 MHz Input Signals) Two-Tone Intermodulation Distortion (FFT For 229 MHz and 230 MHz Input Signals) 0 0 FIN1 = 229 MHz, −7 dBFS FIN2 = 230 MHz, −7 dBFS IMD3 = 85.8 dBFS −20 −40 Amplitude − dB Amplitude − dB −20 FIN1 = 229 MHz, −16 dBFS FIN2 = 230 MHz, −16 dBFS IMD3 = 101.4 dBFS −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G011 Figure 12. 12 G012 Figure 13. Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Two-Tone Intermodulation Distortion (FFT For 300 MHz and 301 MHz Input Signals) Two-Tone Intermodulation Distortion (FFT For 300 MHz and 301 MHz Input Signals) 0 0 FIN1 = 300 MHz, −7 dBFS FIN2 = 301 MHz, −7 dBFS IMD3 = 83.3 dBFS −20 −40 Amplitude − dB Amplitude − dB −20 FIN1 = 300 MHz, −16 dBFS FIN2 = 301 MHz, −16 dBFS IMD3 = 101.9 dBFS −60 −80 −100 −40 −60 −80 −100 −120 −120 0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120 Frequency − MHz Frequency − MHz G013 G014 Figure 14. Figure 15. Input Bandwidth Differential Nonlinearity 1 0.4 fS = 250 MSPS fIN = 10 MHz 0 Differential Nonlinearity − LSB −1 Input Amplitude − dB −2 −3 −4 −5 −6 −7 −8 fS = 250 MSPS AIN = −1 dBFS −9 −10 1 0.2 0.0 −0.2 −0.4 10 100 fIN − Input Frequency − MHz 1k 50 1050 2050 3050 4050 5050 6050 7050 8050 Code G017 Figure 16. G018 Figure 17. Submit Documentation Feedback 13 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Integral Nonlinearity Noise Histogram With Inputs Shorted 2.0 50 45 fS = 250 MSPS 40 1.0 35 Percentage − % INL − Integral Nonlinearity − LSB 1.5 0.5 0.0 −0.5 30 25 20 15 −1.0 10 −1.5 fS = 250 MSPS fIN = 10 MHz −2.0 0 5 0 1000 2000 3000 4000 5000 6000 7000 8000 4109 4110 4111 4112 4113 4114 4115 4116 Code Code Number G019 G020 Figure 18. Figure 19. AC Performance vs Input Amplitude AC Performance vs Input Amplitude 120 120 SFDR (dBFS) SFDR (dBFS) 100 80 SNR (dBFS) Performance − dB Performance − dB 80 100 60 40 SFDR (dBc) 20 SNR (dBFS) 60 40 SFDR (dBc) 20 SNR (dBc) SNR (dBc) 0 0 −20 −20 fS = 250 MSPS fIN = 100 MHz −40 −100 −90 −80 −70 −60 −50 −40 −30 −20 −10 fS = 250 MSPS fIN = 230 MHz −40 −100 −90 −80 −70 −60 −50 −40 −30 −20 −10 0 Input Amplitude − dBFS G021 Figure 20. 14 0 Input Amplitude − dBFS G022 Figure 21. Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Two-Tone Spurious Free Dynamic Range vs Input Amplitude Spurious Free Dynamic Range vs Clock Duty Cycle 80.0 SFDR − Spurious-Free Dynamic Range − dBc SFDR − Spurious-Free Dynamic Range − dB 120 SFDR (dBFS) 100 80 60 SFDR (dBc) 40 90 dBFS Line 20 0 fS = 250 MSPS fIN = 100 MHz −20 −110−100 −90 −80 −70 −60 −50 −40 −30 −20 −10 fS = 250 MSPS 77.5 75.0 fIN = 230 MHz 72.5 70.0 67.5 fIN = 100 MHz 65.0 62.5 60.0 0 0 20 40 Input Amplitude − dBFS 60 80 100 Duty Cycle − % G024 Figure 22. Figure 23. Spurious Free Dynamic Range vs Clock Level Signal-to-Noise Ratio vs Clock Level 78 70 76 69 fIN = 230 MHz SNR − Signal-to-Noise Ratio − dBc SFDR − Spurious-Free Dynamic Range − dBc G023 74 72 fIN = 100 MHz 70 68 66 64 62 fIN = 100 MHz 68 67 fIN = 230 MHz 66 65 64 63 62 61 fS = 250 MSPS fS = 250 MSPS 60 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Clock Amplitude − VP−P 3.5 4.0 60 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Clock Amplitude − VP−P G025 Figure 24. 3.5 4.0 G026 Figure 25. Submit Documentation Feedback 15 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Performance vs Clock Common Mode Level Spurious Free Dynamic Range vs AVDD Across Temperature 80 74 SFDR − Spurious-Free Dynamic Range − dBc fS = 250 MSPS 75 Performance − dBc SFDR 70 SNR 65 60 55 50 0 1 2 3 4 TA = 65°C 73 TA = −40°C 72 TA = 25°C 71 70 TA = 0°C 69 fS = 250 MSPS fIN = 100 MHz 68 4.65 5 Clock Common-Mode Voltage − V 4.85 4.95 5.05 5.15 5.25 5.35 G028 Figure 26. Figure 27. Signal-to-Noise Ratio vs AVDD Across Temperature Spurious Free Dynamic Range vs DRVDD Across Temperature 72.5 70.0 SFDR − Spurious-Free Dynamic Range − dBc fS = 250 MSPS fIN = 100 MHz SNR − Signal-to-Noise Ratio − dBc 4.75 AVDD − Supply Voltage − V G027 69.5 69.0 TA = 65°C 68.5 TA = −40°C TA = 0°C 68.0 TA = 25°C TA = 85°C 67.5 67.0 4.65 4.75 4.85 4.95 5.05 5.15 AVDD − Supply Voltage − V 5.25 5.35 TA = −40°C 72.0 71.5 TA = 25°C 71.0 70.5 TA = 0°C 70.0 69.5 69.0 2.9 fS = 250 MSPS fIN = 100 MHz 3.1 TA = 65°C TA = 85°C 3.3 3.5 DRVDD − Supply Voltage − V G029 Figure 28. 16 TA = 85°C Figure 29. Submit Documentation Feedback 3.7 G030 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) Signal-to-Noise Ratio vs DRVDD Across Temperature 69.0 SNR − Signal-to-Noise Ratio − dBc TA = 25°C TA = 65°C 68.9 fS = 250 MSPS fIN = 100 MHz 68.8 68.7 TA = 85°C TA = 0°C 68.6 68.5 TA = −40°C 68.4 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 DRVDD − Supply Voltage − V 3.7 G031 Figure 30. SNR vs Input Frequency and Sampling Frequency 300 fS - Sampling Frequency - MHz 250 200 69.5 69 150 68.5 68 67.5 67 100 66.5 66 65.5 50 50 150 100 200 250 300 350 400 fIN - Input Frequency - MHz 63 64 65 66 SNR - dBc 67 68 69 M0048-05 Figure 31. Submit Documentation Feedback 17 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 TYPICAL CHARACTERISTICS (continued) SFDR vs Input Frequency and Sampling Frequency 68 300 68 fS - Sampling Frequency - MHz 250 65 80 74 71 71 68 74 83 77 77 86 200 80 80 89 150 68 77 83 74 83 71 86 83 89 86 100 50 77 80 68 89 74 50 150 100 200 250 300 71 350 400 fIN - Input Frequency - MHz 65 70 75 SFDR - dBc Figure 32. 18 Submit Documentation Feedback 80 85 M0048-06 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 APPLICATION INFORMATION Theory of Operation The ADS5444 is a 13 bit, 250 MSPS, monolithic pipeline analog to digital converter. Its bipolar analog core operates from a 5 V supply, while the output uses a 3.3 V supply to provide LVDS compatible outputs. The conversion process is initiated by the rising edge of the external input clock. At that instant, the differential input signal is captured by the input track and hold (T&H) and the input sample is sequentially converted by a series of small 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 four clock cycles, after which the output data is available as a 13 bit parallel word, coded in offset binary format. Input Configuration The analog input for the ADS5444 consists of an analog differential buffer followed by a bipolar track-and-hold. The analog buffer isolates the source driving the input of the ADC from any internal switching. The input common mode is set internally through a 500 Ω resistor connected from 2.4 V to each of the inputs. This results in a differential input impedance of 1 kΩ. For a full-scale differential input, each of the differential lines of the input signal (pins 16 and 17) swings symmetrically between 2.4 +0.55 V and 2.4 -0.55 V. This means that each input has a maximum signal swing of 1.1 VPP for a total differential input signal swing of 2.2 VPP. The maximum swing is determined by the internal reference voltage generator eliminating the need for any external circuitry for this purpose. The ADS5444 obtains optimum performance when the analog inputs are driven differentially. The circuit in Figure 33 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. For voltage gains that would require an impractical transformer turn ratio, a single-ended amplifier driving the transformer is shown in Figure 34). Z0 50 R0 50 AIN 1:1 R 50 AC Signal Source ADS5444 AIN ADT1-1WT Figure 33. Converting a Single-Ended Input to a Differential Signal Using RF Transformers 5V VIN −5 V RS 100 Ω + OPA695 − 0.1 µF 1000 µF RIN 1:1 RT 100 Ω RIN AIN CIN ADS5444 AIN R1 400 Ω R2 57.5 Ω AV = 8V/V (18 dB) Figure 34. Using the OPA695 With the ADS5444 Submit Documentation Feedback 19 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 Application Information (continued) From VIN 50 Ω Source 100 Ω 78.9 Ω 348 Ω 13-Bit 250 MSPS +5V 49.9 Ω 0.22 µF 100 Ω THS4509 49.9 Ω 18 pF AIN ADS5444 AIN CM 49.9 Ω 0.22 µF 78.9 Ω VREF 49.9 Ω 0.22 µF 348 Ω 0.1 µF 0.1 µF Figure 35. Using the THS4509 With the ADS5444 Besides the OPA695, Texas Instruments offers a wide selection of single-ended operational amplifiers that can be selected depending on the application. An RF gain block amplifier, such as Texas Instrument's THS9001, can also be used with an RF transformer for high input frequency applications. For applications requiring dc-coupling with the signal source, a differential input/differential output amplifier like the THS4509 (see Figure 35) is a good solution as it minimizes board space and reduces the number of components. In this configuration, the THS4509 amplifier circuit provides 10 dB of gain, converts the single-ended input to differential, and sets the proper input common-mode voltage to the ADS5444. The 50 Ω resistors and 18 pF capacitor between the THS4509 outputs and ADS5444 inputs (along with the input capacitance of the ADC) limit the bandwidth of the signal to about 70 MHz (-3 dB). Input termination is accomplished via the 78.9 Ω resistor and 0.22 µF capacitor to ground in conjunction with the input impedance of the amplifier circuit. A 0.22 µF capacitor and 49.9 Ω resistor is inserted to ground across the 78.9 Ω resistor and 0.22 µF capacitor on the alternate input to balance the circuit. Gain is a function of the source impedance, termination, and 348 Ω feedback resistor. See the THS4509 data sheet for further component values to set proper 50 Ω termination for other common gains. Since the ADS5444 recommended input common-mode voltage is +2.4 V, the THS4509 is operated from a single power supply input with VS+ = +5 V and VS- = 0 V (ground). This maintains maximum headroom on the internal transistors of the THS4509. Clock Inputs The ADS5444 clock input can be driven with either a differential clock signal or a single-ended clock input, with little or no difference in performance between both configurations. In low input frequency applications, where jitter may not be a big concern, the use of single-ended clock (see Figure 36) could save some cost and board space without any trade-off in performance. When driven on this configuration, it is best to connect CLK to ground with a 0.01 µF capacitor, while CLK is ac-coupled with a 0.01 µF capacitor to the clock source, as shown in Figure 36. Square Wave or Sine Wave CLK 0.01 µF ADS5444 CLK 0.01 µF Figure 36. Single-Ended Clock 20 Submit Documentation Feedback ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 Application Information (continued) 0.1 µF Clock Source 1:4 CLK MA3X71600LCT−ND ADS5444 CLK Figure 37. Differential Clock Nevertheless, for jitter sensitive applications, the use of a differential clock has some advantages (as with any other ADC) at the system level. The first advantage is that it allows for common-mode noise rejection at the PCB level. A differential clock also allows for the use of bigger clock amplitudes without exceeding the absolute maximum ratings. In the case of a sinusoidal clock, this results in higher slew rates and reduces the impact of clock noise on jitter. See Clocking High Speed Data Converters (SLYT075) for more details. Figure 37 shows this approach. The back-to-back Schottky diodes can be added to limit the clock amplitude in cases where this would exceed the absolute maximum ratings, even when using a differential clock. 100 nF MC100EP16DT 100 nF D D CLK VBB Q 499 100 nF Q 100 nF ADS5444 CLK 499 50 Ω 50 Ω 100 nF 113 Ω Figure 38. Differential Clock Using PECL Logic Another possibility is the use of a logic based clock, such as PECL. In this case, the slew rate of the edges will most likely be much higher than the one obtained for the same clock amplitude based on a sinusoidal clock. This solution would minimize the effect of the slope dependent ADC jitter. Using logic gates to square a sinusoidal clock may not produce the best results as logic gates may not have been optimized to act as comparators, adding too much jitter while squaring the inputs. The common-mode voltage of the clock inputs is set internally to 2.4 V using internal 1 kΩ resistors. It is recommended to use ac coupling, but if this scheme is not possible due to, for instance, asynchronous clocking, the ADS5444 features good tolerance to clock common-mode variation. Additionally, the internal ADC core uses both edges of the clock for the conversion process. Ideally, a 50% duty cycle clock signal should be provided. Digital Outputs The ADC provides 13 data outputs (D12 to D0, with D12 being the MSB and D0 the LSB), a data-ready signal (DRY), and an over-range indicator (OVR) that equals a logic high when the output reaches the full-scale limits. The output format is offset binary. It is recommended to use the DRY signal to capture the output data of the ADS5444. Submit Documentation Feedback 21 ADS5444 www.ti.com SLWS162A – AUGUST 2005 – REVISED FEBRUARY 2006 Application Information (continued) The ADS5444 digital outputs are LVDS compatible. Power Supplies The use of low noise power supplies with adequate decoupling is recommended. Linear supplies are the preferred choice versus switched ones, which tend to generate more noise components that can be coupled to the ADS5444. The ADS5444 uses two power supplies. For the analog portion of the design, a 5 V AVDD is used, while for the digital outputs supply (DRVDD) we recommend the use of 3.3 V. All the ground pins are marked as GND, although AGND pins and DRGND pins are not tied together inside the package. Layout Information The evaluation board represents a good guideline of how to layout the board to obtain the maximum performance out of the ADS5444. General design rules as the use of multilayer boards, single ground plane for ADC ground connections and local decoupling ceramic chip capacitors should be applied. The 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 where low jitter is required as high IF sampling. Besides performance oriented rules, care has to be taken when considering the heat dissipation out of the device. The thermal heat sink should be soldered to the board as described in the PowerPad Package section. PowerPAD PACKAGE The PowerPAD package is a thermally enhanced standard size IC package designed to eliminate the use of bulky heatsinks and slugs traditionally used in thermal packages. This package can be easily mounted using standard printed circuit board (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 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 printed circuit board (PCB), using the PCB as a heatsink. 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. 2. Place a 6-by-6 array of thermal vias in the thermal pad area. These holes should be 13 mils 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 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 SLMA004 Application Brief PowerPAD Made Easy or the SLMA002 Technical Brief PowerPAD Thermally Enhanced Package. 22 Submit Documentation Feedback PACKAGE OPTION ADDENDUM www.ti.com 31-Oct-2007 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty ADS5444IPFP ACTIVE HTQFP PFP 80 ADS5444IPFPR ACTIVE HTQFP PFP 80 96 Lead/Ball Finish MSL Peak Temp (3) Green (RoHS & no Sb/Br) CU NIPDAU Level-4-260C-72 HR 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-4-260C-72 HR (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 1-Jul-2008 TAPE AND REEL INFORMATION *All dimensions are nominal Device ADS5444IPFPR Package Package Pins Type Drawing HTQFP PFP 80 SPQ Reel Reel Diameter Width (mm) W1 (mm) 1000 330.0 24.4 Pack Materials-Page 1 A0 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 15.0 15.0 1.5 20.0 24.0 Q2 PACKAGE MATERIALS INFORMATION www.ti.com 1-Jul-2008 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS5444IPFPR HTQFP PFP 80 1000 346.0 346.0 41.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. 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