ADS6244IRGZR

ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 DUAL CHANNEL, 14-BIT, 125/105/80/65 MSPS ADC WITH SERIAL LVDS OUTPUTS Check for Samples: ADS6245, ADS6244, ADS6243, ADS6242 FEATURES • 1 • • • • • • • • • • Maximum Sample Rate: 125 MSPS 14-Bit Resolution with No Missing Codes Simultaneous Sample and Hold 3.5 dB Coarse Gain and up to 6 dB Programmable Fine Gain for SFDR/SNR TradeOff Serialized LVDS Outputs with Programmable Internal Termination Option Supports Sine, LVCMOS, LVPECL, LVDS Clock Inputs and Amplitude down to 400 mVpp Internal Reference with External Reference Support No External Decoupling Required for References 3.3-V Analog and Digital Supply 48 QFN Package (7 mm × 7 mm) • Pin Compatible 12-Bit Family (ADS622X SLAS543A) Feature Compatible Quad Channel Family (ADS644X - SLAS531A and ADS642X SLAS532A) APPLICATIONS • • • • Base-Station IF Receivers Diversity Receivers Medical Imaging Test Equipment Table 1. ADS62XX Dual Channel Family 125 MSPS 105 MSPS 80 MSPS 65 MSPS ADS624X 14 Bit ADS6245 ADS6244 ADS6243 ADS6242 ADS622X 12 Bit ADS6225 ADS6224 ADS6223 ADS6222 Table 2. Performance Summary SFDR, dBc SINAD, dBFS ADS6245 ADS6244 ADS6243 ADS6242 Fin = 10MHz (0 dB gain) 87 91 92 93 Fin = 170MHz (3.5 dB gain) 79 83 84 84 Fin = 10MHz (0 dB gain) 73.4 73.4 74.2 74.3 Fin = 170MHz (3.5 dB gain) 68.3 69.3 69.4 70 500 405 350 315 Power, per channel, mW DESCRIPTION ADS6245/ADS6244/ADS6243/ADS6242 (ADS624X) is a family of high performance 14-bit 125/105/80/65 MSPS dual channel A-D converters. Serial LVDS data outputs reduce the number of interface lines, resulting in a compact 48-pin QFN package (7 mm × 7mm) that allows for high system integration density. The device includes 3.5 dB coarse gain option that can be used to improve SFDR performance with little degradation in SNR. In addition to the coarse gain, fine gain options also exist, programmable in 1dB steps up to 6dB. The output interface is 2-wire, where each ADC data is serialized and output over two LVDS pairs. This makes it possible to halve the serial data rate (compared to a 1-wire interface) and restrict it to less than 1Gbps easing receiver design. The ADS624X also includes the traditional 1-wire interface that can be used at lower sampling frequencies. An internal phase lock loop (PLL) multiplies the incoming ADC sampling clock to derive the bit clock. The bit clock is used to serialize the 14-bit data from each channel. In addition to the serial data streams, the frame and bit clocks are also transmitted as LVDS outputs. 1 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. 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 © 2007–2013, Texas Instruments Incorporated ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. DESCRIPTION (CONTINUED) The LVDS output buffers have features such as programmable LVDS currents, current doubling modes and internal termination options. These can be used to widen eye-openings and improve signal integrity, easing capture by the receiver. The ADC channel outputs can be transmitted either as MSB or LSB first and 2s complement or straight binary. LVDD LGND CAP AVDD AGND ADS624X has internal references, but can also support an external reference mode. The device is specified over the industrial temperature range (–40°C to 85°C). CLKP CLKM BIT Clock DCLKP DCLKM FRAME Clock FCLKP FCLKM PLL SHA 14-Bit ADC Digital Encoder and Serializer SHA 14-Bit ADC Digital Encoder and Serializer INA_P INA_M INB_P VCM DA1_P DA1_M DB0_P DB0_M DB1_P DB1_M REFM REFP INB_M DA0_P DA0_M Reference Parallel Interface Serial Interface 2 Submit Documentation Feedback SCLK RESET SEN SDATA CFG4 CFG3 CFG1 CFG2 PDNA PDNB ADS624x B0199-05 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 PACKAGE/ORDERING INFORMATION (1) PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ADS6245 QFN-48 (2) RGZ –40°C to 85°C AZ6245 ADS6244 QFN-48 (2) RGZ –40°C to 85°C AZ6244 ADS6243 QFN-48 (2) RGZ –40°C to 85°C AZ6243 ADS6242 (1) (2) QFN-48 (2) RGZ –40°C to 85°C AZ6242 ORDERING NUMBER TRANSPORT MEDIA, QUANTITY ADS6245IRGZT 250, Tape/reel ADS6245IRGZR 2500, Tape/reel ADS6244IRGZT 250, Tape/reel ADS6244IRGZR 2500, Tape/reel ADS6243IRGZT 250, Tape/reel ADS6243IRGZR 2500, Tape/reel ADS6242IRGZT 250, Tape/reel ADS6242IRGZR 2500, Tape/reel For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. For thermal pad size on the package, see the mechanical drawings at the end of this data sheet. θJA = 23.17 °C/W (0 LFM air flow), θJC = 22.1 °C/W when used with 2 oz. copper trace and pad soldered directly to a JEDEC standard four layer 3 in. x 3 in. PCB. ABSOLUTE MAXIMUM RATINGS (1) VALUE UNIT AVDD Supply voltage range –0.3 to 3.9 V LVDD Supply voltage range –0.3 to 3.9 V Voltage between AGND and DGND –0.3 to 0.3 V Voltage between AVDD to LVDD –0.3 to 3.3 V Voltage applied to external pin, VCM –0.3 to 2.0 V Voltage applied to analog input pins –0.3V to minimum ( 3.6, AVDD + 0.3V) V TA Operating free-air temperature range –40 to 85 °C TJ Operating junction temperature range Tstg Storage temperature range 125 °C –65 to 150 °C 220 °C Lead temperature 1,6 mm (1/16") from the case for 10 seconds (1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 3 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT AVDD Analog supply voltage 3.0 3.3 3.6 V LVDD 3.0 3.3 3.6 V SUPPLIES LVDS Buffer supply voltage ANALOG INPUTS Differential input voltage range 2 Vpp 1.5 ±0.1 Input common-mode voltage Voltage applied on VCM in external reference mode 1.45 1.50 V 1.55 V CLOCK INPUT Input clock sample rate, Fs ADS6245 5 125 ADS6244 5 105 ADS6243 5 80 ADS6242 5 Sine wave, ac-coupled Input clock amplitude differential (VCLKP – VCLKM) 0.4 LVPECL, ac-coupled 65 1.5 ± 0.8 LVDS, ac-coupled Vpp ± 0.35 LVCMOS, ac-coupled MSPS 3.3 Input Clock duty cycle 35% 50% 65% DIGITAL OUTPUTS Without internal termination CLOAD Maximum external load capacitance from each output pin to DGND RLOAD Differential load resistance (external) between the LVDS output pairs TA Operating free-air temperature 5 With internal termination pF 10 Ω 100 –40 85 °C ELECTRICAL CHARACTERISTICS Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER ADS6245 Fs = 125 MSPS MIN RESOLUTION TYP ADS6244 Fs = 105 MSPS MAX MIN TYP ADS6243 Fs = 80 MSPS MAX MIN TYP ADS6242 Fs = 65 MSPS MAX MIN TYP UNIT MAX 14 14 14 14 Bits 2.0 2.0 2.0 2.0 VPP 7 7 7 7 pF Analog input bandwidth 500 500 500 500 MHz Analog input common mode current (per input pin of each ADC) 155 130 100 81 μA ANALOG INPUT Differential input voltage range Differential input capacitance REFERENCE VOLTAGES VREFB Internal reference bottom voltage 1.0 1.0 1.0 1.0 V VREFT Internal reference top voltage 2.0 2.0 2.0 2.0 V ΔVREF Internal reference error, (VREFT–VREFB) VCM Common mode output voltage 1.5 1.5 1.5 1.5 V VCM output current capability ±4 ±4 ±4 ±4 mA 4 –15 Submit Documentation Feedback ±2 15 –15 ±2 15 –15 ±2 15 –15 ±2 15 mV Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 ELECTRICAL CHARACTERISTICS (continued) Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER ADS6245 Fs = 125 MSPS MIN TYP ADS6244 Fs = 105 MSPS MAX MIN 15 –15 TYP ADS6243 Fs = 80 MSPS MAX MIN 15 –15 TYP ADS6242 Fs = 65 MSPS MAX MIN 15 –15 TYP UNIT MAX DC ACCURACY No missing codes EO Offset error, across devices and across channels within a device Assured –15 Offset error temperature coefficient, across devices and across channels within a device ±2 Assured 0.05 ±2 Assured 0.05 Assured ±2 0.05 ±2 15 0.05 mV mV/°C There are two sources of gain error - internal reference inaccuracy and channel gain error EGREF Gain error due to internal reference inaccuracy alone, (ΔVREF /2.0) % –0.75 Reference gain error temperature coefficient EGCHAN Gain error of channel alone, across devices and across channels within a device (1) Differential nonlinearity INL Integral nonlinearity PSRR DC power supply rejection ratio 0.75 –0.75 0.0125 –1 Channel gain error temperature coefficient, across devices and across channels within a device DNL ±0.1 ±0.3 ±0.1 0.75 –0.75 0.0125 1 –1 0.005 ±0.3 ±0.1 0.75 –0.75 0.0125 1 –1 0.005 ±0.1 0.75 Δ%/°C 0.0125 ±0.3 1 –1 0.005 ±0.3 % FS 1 % FS Δ%/°C 0.005 –0.95 ±0.6 2.5 –0.9 ±0.6 2.5 –0.9 ±0.5 2.0 –0.9 ±0.5 2.5 -5 ±3 5 -5 ±3 5 -4.5 ±2 4.5 -4.5 ±2 4.5 LSB LSB 0.5 0.5 0.5 0.5 mV/V POWER SUPPLY ICC Total supply current 300 245 210 190 mA IAVDD Analog supply current 237 185 155 140 mA ILVDD LVDS supply current 63 60 55 50 Total power 1.0 1.2 0.81 0.97 0.7 0.85 0.63 0.8 W Power down (with input clock stopped) 77 150 77 150 77 150 77 150 mW (1) mA This is specified by design and characterization; it is not tested in production. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 5 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com ELECTRICAL CHARACTERISTICS Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER ADS6245 Fs = 125 MSPS TEST CONDITIONS MIN TYP MAX ADS6244 Fs = 105 MSPS MIN TYP MAX ADS6243 Fs = 80 MSPS MIN TYP MAX ADS6242 Fs = 65 MSPS MIN TYP UNIT MAX DYNAMIC AC CHARACTERISTICS Fin = 10 MHz Fin = 50 MHz 68.5 Fin = 70 MHz SNR Signal to noise ratio Fin = 230 MHz 72.8 70.7 3.5 dB Coarse gain 69.4 69.7 69.7 70.2 0 dB gain 68.7 68.8 68.1 69.2 3.5 dB Coarse gain 68.1 68.2 67.7 68.9 73.4 73.4 72.3 71.7 68 72.2 72 0 dB gain 67.9 69.8 69.9 70.3 3.5 dB Coarse gain 68.3 69.3 69.4 70 0 dB gain 67.8 67.7 67.6 68.3 3.5 dB Coarse gain 67.9 67.6 68.1 68.4 1.05 1.05 1.05 1.05 87 91 92 93 78 Fin = 100 MHz 79 77 87.5 79 86 86 88 84 82 0 dB gain 76 79 80 81 3.5 dB Coarse gain 79 83 84 84 0 dB gain 77 77 78 79 3.5 dB Coarse gain 80 80 82 82 93 94 87 88 73 Fin = 70 MHz 87 Fin = 100 MHz 90 LSB dBc 97 79 92 88 90 92 89 90 87 87 0 dB gain 83 84 86 86 3.5 dB Coarse gain 85 86 88 88 0 dB gain 80 81 82 83 3.5 dB Coarse gain 82 83 84 85 Submit Documentation Feedback 74 96 77 dBFS 88 86 Fin = 50 MHz 74 73.2 81 Fin = 10 MHz 6 73.7 72 81 dBFS 74.3 70 71.8 Fin = 70 MHz Fin = 230 MHz 73.5 73 73 68.5 74.2 69.5 72 Fin = 50 MHz Fin = 170 MHz 73.6 70.5 Fin = 10 MHz HD2 Second harmonic 73.4 72.7 Inputs tied to common-mode Fin = 230 MHz 74 73 70.2 Fin = 100 MHz Fin = 170 MHz 74.5 70.5 72.2 71.2 Fin = 230 MHz 73.8 69.9 Fin = 70 MHz SINAD Signal to noise and Fin = 170 distortion ratio MHz 69 74.4 70 72.1 Fin = 50 MHz SFDR Spurious free dynamic range 73.2 0 dB gain Fin = 10 MHz RMS Output noise 73.8 73.1 72.7 Fin = 100 MHz Fin = 170 MHz 73.7 dBc Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 ELECTRICAL CHARACTERISTICS (continued) Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER ADS6245 Fs = 125 MSPS TEST CONDITIONS MIN Fin = 10 MHz Fin = 50 MHz HD3 Third harmonic THD Total harmonic distortion MAX MIN TYP 87 91 81 79 Fin = 70 MHz 78 Fin = 100 MHz MIN TYP 77 87.5 MAX ADS6242 Fs = 65 MSPS MIN 92 TYP 88 86 86 88 84 82 0 dB gain 76 79 80 81 3.5 dB Coarse gain 79 83 84 84 0 dB gain 77 77 78 79 3.5 dB Coarse gain 80 80 82 82 Fin = 10 MHz 91 91 94 95 Fin = 50 MHz 87 87 92 93 Fin = 100 MHz 90 90 91 92 Fin = 170 MHz 88 88 90 90 Fin = 230 MHz 87 87 87 87 Fin = 10 MHz 86 89.5 89 78 78.5 Fin = 50 MHz 71 Fin = 70 MHz 77 77 80 84 84 86 83 80.5 Fin = 170 MHz 73.5 77 78.5 79.5 Fin = 230 MHz 74 75 76 77 Fin = 50 MHz IMD 2-Tone intermodulatio n distortion F1= 46.09 MHz, F2 = 50.09 MHz 88 90 96 100 F1= 185.09 MHz, F2 = 190.09 MHz 86 88 93 96 Near channel Cross-talk signal frequency = 10 MHz 90 92 94 100 Far channel Cross-talk signal frequency = 10 MHz 103 105 106 108 1 1 1 1 Clock cycles 35 35 35 35 dBc Cross-talk 11.3 11.9 11.4 dBc ENOB Effective number of bits Fin = 70 MHz 11.1 dBc 85.6 84.5 11.7 dBc 91 85.5 Fin = 100 MHz 11.0 72 75 UNIT MAX 93 79 86 Fin = 170 MHz 74 MAX ADS6243 Fs = 80 MSPS 81 Fin = 230 MHz Worst harmonic (other than HD2, HD3) 73 TYP ADS6244 Fs = 105 MSPS 12 Bits 11.7 dBFS dBc Input overload recovery Recovery to within 1% (of final value) for 6-dB overload with sine wave input AC PSRR Power Supply Rejection Ratio < 100 MHz signal, 100 mVPP on AVDD supply Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 7 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com DIGITAL CHARACTERISTICS The DC specifications refer to the condition where the digital outputs are not switching, but are permanently at a valid logic level 0 or 1 AVDD = LVDD = 3.3V, IO = 3.5mA, RLOAD = 100Ω (1). All LVDS specifications are characterized, but not tested at production. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DIGITAL INPUTS High-level input voltage 2.4 V Low-level input voltage 0.8 V High-level input current 10 μA Low-level input current 10 μA DIGITAL OUTPUTS Input capacitance High-level output voltage Low-level output voltage 250 Output offset voltage VOS Common-mode voltage of OUTP and OUTM Output capacitance Output capacitance inside the device, from either output to ground 8 pF mV 1025 Output differential voltage |VOD| (1) 4 1375 350 mV 450 mV 1200 mV 2 pF IO refers to the LVDS buffer current setting, RLOAD is the external differential load resistance between the LVDS output pair Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TIMING SPECIFICATIONS (1) Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP clock amplitude, CL = 5 pF (2), IO = 3.5 mA, RL = 100 Ω (3), no internal termination, unless otherwise noted. PARAMETER tJ TEST CONDITIONS ADS6245 MIN Aperture jitter Uncertainty in the sampling instant ADS6244 TYP MAX MIN 250 TYP ADS6243 MAX MIN 250 ADS6242 TYP MAX MIN 250 TYP UNIT MAX 250 fs rms Interface: 2-wire, DDR bit clock, 14x serialization tsu Data setup time (4) (5) (6) From data cross-over to bit clock crossover 0.35 0.55 0.45 0.65 0.65 0.85 0.8 1.1 ns th Data hold time (4) (5) (6) From bit clock cross-over to data crossover 0.35 0.58 0.5 0.7 0.7 0.9 0.8 1.1 ns Frame setup time From frame clock rising edge crossover to bit clock rising edge crossover 0.35 0.55 0.45 0.65 0.65 0.85 0.8 1.1 ns th Frame hold time From bit clock falling edge cross-over to frame clock falling edge cross-over 0.35 0.58 0.5 0.7 0.7 0.9 0.8 1.1 ns tpd_cl Clock propagation delay (6) Input clock rising edge cross-over to frame clock rising edge cross-over 3.4 4.4 3.4 4.4 3.4 4.4 3.4 4.4 tsu k 5.4 5.4 5.4 5.4 ns Bit clock cycle-cycle jitter (5) 350 350 350 350 ps pp Frame clock cycle-cycle jitter (5) 75 75 75 75 ps pp Below specifications apply for 5 MSPS ≤ Sampling freq ≤ 125 MSPS and all interface options tA (1) (2) (3) (4) (5) (6) Aperture delay Delay from input clock rising edge to the actual sampling instant Aperture delay variation Channelchannel within same device 1 2 –250 ±80 3 1 2 3 1 2 3 1 2 3 ns 250 –250 ±80 250 –250 ±80 250 –250 ±80 250 ps Timing parameters are ensured by design and characterization and not tested in production. CL is the external single-ended load capacitance between each output pin and ground. Io refers to the LVDS buffer current setting; RL is the external differential load resistance between the LVDS output pair. Timing parameters are measured at the end of a 2 inch pcb trace (100-Ω characteristic impedance) terminated by RLand CL. Setup and hold time specifications take into account the effect of jitter on the output data and clock. Refer to Output Timings in application section for timings at lower sampling frequencies and other interface options. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 9 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TIMING SPECIFICATIONS(1) (continued) Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP clock amplitude, CL = 5 pF (2), IO = 3.5 mA, RL = 100 Ω (3), no internal termination, unless otherwise noted. PARAMETER ADC Latency (7) Wake up time ADS6245 TEST CONDITIONS MIN Time for a sample to propagate to ADC outputs, see Figure 1 ADS6244 TYP MAX MIN 12 TYP ADS6243 MAX MIN 12 ADS6242 TYP MAX MIN 12 TYP MAX UNIT Clock cycles 12 Time to valid data after coming out of global power down 100 100 100 100 μs Time to valid data after input clock is restarted 100 100 100 100 μs Time to valid data after coming out of channel standby 200 200 200 200 clock cycles tRISE Data rise time From –100 mV to +100 mV 50 100 200 50 100 200 50 100 200 50 100 200 ps tFALL Data fall time From +100 mV to –100 mV 50 100 200 50 100 200 50 100 200 50 100 200 ps tRISE Bit clock and Frame clock rise time From –100 mV to +100 mV 50 100 200 50 100 200 50 100 200 50 100 200 ps tFALL Bit clock and Frame clock fall time From +100 mV to –100 mV 50 100 200 50 100 200 50 100 200 50 100 200 ps LVDS Bit clock duty cycle 45% 50% 55% 45% 50% 55% 45% 50% 55% 45% 50% 55% LVDS Frame clock duty cycle 47% 50% 53% 47% 50% 53% 47% 50% 53% 47% 50% 53% (7) 10 Note that the total latency = ADC latency + internal serializer latency. The serializer latency depends on the interface option selected as listed in Table 28. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Sample N+13 Sample N+12 Sample N+11 Sample N Input Signal tA Input Clock CLKM CLKP tPD_CLK Latency 12 Clocks Bit Clock Output Data DCLKP DCLKM DOP D13 D12 D11 D10 D6 D5 D4 D3 D2 D1 D0 D13 D12 D11 D10 Sample N–1 Frame Clock D6 D5 D4 D3 D2 D1 D0 DOM Sample N FCLKM FCLKP T0105-04 Figure 1. Latency Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 11 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com DCLKP Bit clock DCLKM tsu th tsu th P Output data (differential) DA, DB, DC, DD Dn+1 Dn M tsu th FCLKP Frame clock FCLKM Figure 2. LVDS Timings 12 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 DEVICE PROGRAMMING MODES ADS624X offers flexibility with several programmable features that are easily configured. The device can be configured independently using either parallel interface control or serial interface programming. In addition, the device supports a third configuration mode, where both the parallel interface and the serial control registers are used. In this mode, the priority between the parallel and serial interfaces is determined by a priority table (Table 4). If this additional level of flexibility is not required, the user can select either the serial interface programming or the parallel interface control. USING PARALLEL INTERFACE CONTROL ONLY To control the device using parallel interface, keep RESET tied to high (LVDD). Pins CFG1, CFG2, CFG3, CFG4, PDNA, PDNB, SEN, SCLK, and SDATA are used to directly control certain functions of the ADC. After power-up, the device will automatically get configured as per the parallel pin voltage settings (Table 5 to Table 9) and no reset is required. In this mode, SEN, SCLK, and SDATA function as parallel interface control pins. Frequently used functions are controlled in this mode—output data interface and format, power down modes, coarse gain and internal/external reference. The parallel pins can be configured using a simple resistor string (with 10% tolerance resistors) as illustrated in Figure 3. Table 3 has a description of the modes controlled by the parallel pins. Table 3. Parallel Pin Definition PIN SEN CONTROL FUNCTIONS Coarse gain and internal/external reference. SCLK, SDATA Sync, deskew patterns and global power down. PDNA, PDNB Dedicated pins for individual channel power down CFG1 1-wire/2-wire and DDR/SDR bit clock CFG2 14x/16x serialization and SDR bit clock capture edge CFG3 Reserved function. Tie CFG3 to Ground. CFG4 MSB/LSB First and data format. USING SERIAL INTERFACE PROGRAMMING ONLY In this mode, SEN, SDATA, and SCLK function as serial interface pins and are used to access the internal registers of ADC. The registers must first be reset to their default values either by applying a pulse on RESET pin or by a high setting on the bit (in register ). After reset, the RESET pin must be kept low. The serial interface section describes the register programming and register reset in more detail. Since the parallel pins (CFG1-4, PDNA and PDNB) are not used in this mode, they must be tied to ground. The register override bit - D10 in register 0x0D has to be set high to disable the control of parallel interface pins in this serial interface control ONLY mode. USING BOTH THE SERIAL INTERFACE AND PARALLEL CONTROLS For increased flexibility, a combination of serial interface registers and parallel pin controls (CFG1-4, PDNA and PDNB) can also be used to configure the device. The parallel interface control pins CFG1 to CFG4 and PDNA, PDNB are available. After power-up, the device will automatically get configured as per the parallel pin voltage settings (Table 5 to Table 12) and no reset is required. A simple resistor string can be used as illustrated in Figure 3. SEN, SDATA, and SCLK function as serial interface pins and are used to access the internal registers of ADC. The registers must first be reset to their default values either by applying a pulse on RESET pin or by a high setting on the bit (in register ). After reset, the RESET pin must be kept low. The serial interface section describes the register programming and register reset in more detail. Since some functions are controlled using both the parallel pins and serial registers, the priority between the two is determined by a priority table (Table 4). Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 13 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Table 4. Priority Between Parallel Pins and Serial Registers PIN FUNCTIONS SUPPORTED CFG1 to CFG4 PRIORITY As described in Register bits can control the modes ONLY if the bit is high. If the bit is LOW, then the control voltage on these parallel pins determines the function as per Tables PDNA Channel A power down D2 bit of register 0x00 controls channel A power down ONLY if PDNA pin is LOW. If PDNA is high, channel A is powered down. PDNB Channel B power down D3 bit of register 0x00 controls channel B power down ONLY if PDNB pin is LOW. If PDNB is high, channel B is powered down. SEN Serial Interface Enable COARSE GAIN setting is controlled by bit D5 of register 0X0D ONLY if the bit is high. Else, it is in default register setting of 0 dB COARSE GAIN. INTERNAL/ EXTERNAL Reference setting is determined by bit D6 of register 0x00. SCLK, SDATA Serial Interface Clock and Serial Interface Data pins D7, D6, D5 bits of register 0x0A control the SYNC and DESKEW output patterns. Power down is determined by bit D0 of 0x00 register. LVDD LVDD (5/6) LVDD R (5/8) LVDD 3R (5/8) LVDD (5/6) LVDD GND 2R LVDD GND 2R LVDD (3/8) LVDD (3/6) LVDD (3/8) LVDD (3/6) LVDD 3R 3R To SEN Pin To CFGx Pins GND GND Figure 3. Simple Scheme to Configure Parallel Pins DESCRIPTION OF PARALLEL PINS Table 5. SCLK, SDATA Control Pins SCLK SDATA LOW LOW NORMAL conversion. DESCRIPTION LOW HIGH SYNC - ADC outputs sync pattern on all channels. This pattern can be used by the receiver to align the deserialized data to the frame boundary. See Capture Test Patterns for details. HIGH LOW POWER DOWN –Global power down, all channels of the ADC are powered down, including internal references, PLL and output buffers. HIGH HIGH DESKEW - ADC outputs deskew pattern on all channels. This pattern can be used by the receiver to ensure deserializer uses the right clock edge. See Capture Test Patterns for details. Table 6. SEN Control Pin SEN 0 (3/8)LVDD External reference and 3.5 dB coarse gain (Full-scale = 1.34V pp) (5/8)LVDD Internal reference and 3.5 dB coarse gain (Full-scale = 1.34V pp) LVDD 14 DESCRIPTION External reference and 0 dB coarse gain (Full-scale = 2V pp) Internal reference and 0 dB coarse gain (Full-scale = 2V pp) Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Independent of the programming mode used, after power-up the parallel pins PDNA, PDNB, CFG1 to CFG4 will automatically configure the device as per the voltage applied (Table 7 to Table 12). Table 7. PDNA Control Pin PDNA DESCRIPTION 0 Normal operation AVDD Channel A ADC Power down Table 8. PDNB Control Pin PDNB DESCRIPTION 0 Normal operation AVDD Channel B ADC Power down Table 9. CFG1 Control Pin CFG1 DESCRIPTION 0 (default) + 200mV DDR bit clock and 1-wire interface (3/6) LVDD ± 200mV Not used (5/6) LVDD ± 200mV SDR bit clock and 2-wire interface LVDD - 200mV DDR bit clock and 2-wire interface Table 10. CFG2 Control Pin CFG2 DESCRIPTION 0 (default) + 200mV 14x serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (3/6) LVDD ± 200mV 16x serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (5/6) LVDD ± 200mV 16x serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) LVDD - 200mV 14x serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) Table 11. CFG3 Control Pin CFG3 RESERVED - TIE TO GROUND Table 12. CFG4 Control Pin CFG4 DESCRIPTION 0 (default) + 200mV MSB First and 2s complement (3/6) LVDD ± 200mV MSB First and Offset binary (5/6) LVDD ± 200mV LSB First and Offset binary LVDD - 200mV LSB First and 2s complement Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 15 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com SERIAL INTERFACE The ADC has a serial interface formed by pins SEN (serial interface enable), SCLK (serial interface clock), SDATA (serial interface data) and RESET. Serial shift of bits into the device is enabled when SEN is low. Serial data SDATA is latched at every falling edge of SCLK when SEN is active (low). The serial data is loaded into the register at every 16th SCLK falling edge when SEN is low. In case the word length exceeds a multiple of 16 bits, the excess bits are ignored. Data can be loaded in multiple of 16-bit words within a single active SEN pulse. The interface can work with SCLK frequency from 20 MHz down to very low speeds (few hertz) and even with non50% duty cycle SCLK. The first 5-bits of the 16-bit word are the address of the register while the next 11 bits are the register data. Register Reset After power-up, the internal registers must be reset to their default values. This can be done in one of two ways: 1. Either by applying a high-going pulse on RESET (of width greater than 10ns) OR 2. By applying software reset. Using the serial interface, set the bit in register 0x00 to high – this resets the registers to their default values and then self-resets the bit to LOW. When RESET pin is not used, it must be tied to LOW. Register Address SDATA A4 A3 A2 A1 Register Data A0 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 t(DH) t(SCLK) t(DSU) SCLK t(SLOADH) t(SLOADS) SEN RESET T0109-03 Figure 4. Serial Interface Timing 16 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 SERIAL INTERFACE TIMING CHARACTERISTICS Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3V, unless otherwise noted. PARAMETER MIN TYP > DC MAX UNIT 20 MHz fSCLK SCLK Frequency, fSCLK = 1/tSCLK tSLOADS SEN to SCLK Setup time 25 ns tSLOADH SCLK to SEN Hold time 25 ns tDSU SDATA Setup time 25 ns tDH SDATA Hold time 25 ns 100 ns Time taken for register write to take effect after 16th SCLK falling edge RESET TIMING Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3V, unless otherwise noted. PARMATER CONDITIONS MIN t1 Power-on delay time Delay from power-up of AVDD and LVDD to RESET pulse active t2 Reset pulse width t3 tPO TYP MAX UNIT 5 ms Pulse width of active RESET signal 10 ns Register write delay time Delay from RESET disable to SEN active 25 Power-up delay time Delay from power-up of AVDD and LVDD to output stable ns 6.5 ms Power Supply AVDD, LVDD t1 RESET t2 t3 SEN T0108-03 Figure 5. Reset Timing Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 17 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com SERIAL REGISTER MAP Table 13. Summary of Functions Supported By Serial Interface REGISTER ADDRESS A4 - A0 REGISTER FUNCTIONS (1) D10 D9 D8 D7 00 S/W RESET 0 0 0 04 0 0 0 0 0 DATA FORMAT 2S COMP OR STRAIGHT BINARY 0 0A 0D 10 11 (1) (2) (3) 18 0 D5 INTERNAL OR EXTERNAL D4 D3 POWER DOWN CHB 0 D2 POWER DOWN CH A INPUT CLOCK BUFFER GAIN CONTROL TEST PATTERNS 0 0 0 D1 D0 0 GLOBAL POWER DOWN 0 0 0 0 CUSTOM PATTERN (LOWER 11 BITS) 0B 0C D6 (2) (3) FINE GAIN CONTROL (1dB to 6 dB) OVERRIDE BIT 0 0 0 0 0 BYTE-WISE OR BITWISE MSB OR LSB FIRST COURSE GAIN ENABLE LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS WORD-WISE CONTROL 0 0 CUSTOM PATTERN (UPPER 5 BITS) FALLING OR RISING BIT CLOCK CAPTURE EDGE 0 LVDS CURRENT SETTINGS 0 0 14-BIT OR 16-BIT SERIALIZE DDR OR SDR BIT CLOCK 1-WIRE OR 2-WIRE INTERFACE LVDS CURRENT DOUBLE LVDS INTERNAL TERMINATION - DATA OUTPUTS The unused bits in each register (shown by blank cells in above table) must be programmed as 0. Multiple functions in a register can be programmed in a single write operation. After a hardware or software reset, all register bits are cleared to ‘0’. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 DESCRIPTION OF SERIAL REGISTERS Note: After a hardware or software reset, all register bits are cleared to ‘0’. Table 14. Serial Register A REGISTER ADDRESS A4 - A0 00 BITS D10 D9 S/W RESET 0 D8 0 D7 0 D6 D5 0 INTERNAL OR EXTERNAL D4 0 D3 POWER DOWN CHB D2 POWER DOWN CH A D1 D0 0 GLOBAL POWER DOWN D0 - D4 Power down modes D0 0 Normal operation 1 Global power down, including all channels ADCs, internal references, internal PLL and output buffers D2 0 CH A powered up 1 CH A ADC powered down D3 0 CH B powered up 1 CH B ADC powered down D5 Reference 0 Internal reference enabled 1 External reference enabled D10 1 Software reset applied – resets all internal registers and self-clears to 0 Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 19 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Table 15. Serial Register B REGISTER ADDRESS A4 - A0 04 BITS D10 D9 0 D8 0 0 D7 D6 D5 D4 D3 D2 INPUT CLOCK BUFFER GAIN CONTROL 0 D6 - D2 Input clock buffer gain control 11000 Gain 0 Minimum gain 00000 Gain 1, default after reset 01100 Gain 2 01010 Gain 3 01001 Gain 4 01000 Gain 5 Maximum gain D1 D0 0 0 Table 16. Serial Register C REGISTER ADDRESS A4 - A0 0A BITS D10 D9 D8 0 DATA DORMAT 2S COMP OR STRAIGHT BINARY 0 D7 D6 D5 TEST PATTERNS D4 D3 D2 D1 D0 0 0 0 0 0 D7 - D5 Capture test patterns 000 Normal ADC operation 001 Output all zeros 010 Output all ones 011 Output toggle pattern 100 Unused 101 Output custom pattern (contents of CUSTOM pattern registers 0x0B and 0x0C) 110 Output DESKEW pattern (serial stream of 1010..) 111 Output SYNC pattern D9 Data format selection 0 2s complement format 1 Straight binary format 20 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Table 17. Serial Register D REGISTER ADDRESS A4 - A0 BITS D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 D1 D0 CUSTOM PATTERN (LOWER 11 BITS) 0B D10 - D0 Lower 11 bits of custom pattern … Table 18. Serial Register E REGISTER ADDRESS A4 - A0 0C BITS D10 D9 D8 FINE GAIN CONTROL (1 dB to 6 dB) D7 D6 D5 0 0 0 D4 D3 D2 CUSTOM PATTERN (UPPER 5 BITS) D4 - D0 Upper 5 bits of custom pattern … D10-D8 Fine gain control 000 0 dB gain (Full-scale range = 2.00 Vpp) 001 1 dB gain (Full-scale range = 1.78 Vpp) 010 2 dB gain (Full-scale range = 1.59 Vpp) 011 3 dB gain (Full-scale range = 1.42 Vpp) 100 4 dB gain (Full-scale range = 1.26 Vpp) 101 5 dB gain (Full-scale range = 1.12 Vpp) 110 6 dB gain (Full-scale range = 1.00 Vpp) Table 19. Serial Register F REGISTER ADDRESS A4 - A0 0D BITS D10 D9 OVER-RIDE BITE D8 0 0 D7 BYTE-WISE OR BITWISE D6 MSB OR LSB FIRST D5 D4 D3 D2 D1 D0 COURSE GAIN ENABLE FALLING OR RISING BIT CLOCK CAPTURE EDGE 0 14-BIT OR 16-BIT SERIALIZE DDR OR SDR BIT CLOCK 1-WIRE OR 2-WIRE INTERFACE D0 Interface selection 0 1 wire interface 1 2 wire interface D1 Bit clock selection (only in 2-wire interface) 0 DDR bit clock 1 SDR bit clock D2 Serialization factor selection 0 14X serialization 1 16X serialization D4 Bit clock capture edge (only when SDR bit clock is selected, D1=1) 0 Capture data with falling edge of bit clock 1 Capture data with rising edge of bit clock D5 Coarse gain control 0 0 dB coarse gain Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 21 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 1 3.5dB coarse gain (Full-scale range = 1.34 Vpp) D6 MSB or LSB first selection 0 MSB First 1 LSB First D7 Byte/bit wise outputs (only when 2-wire is selected) 0 Byte wise 1 Bit wise D10 Over-ride bit. All the functions in register 0x0D can also be controlled using the parallel control pins. By setting bit =1, the contents of register 0x0D will over-ride the settings of the parallel pins. 0 Disable over-ride 1 Enable over-ride Table 20. Serial Register G REGISTER ADDRESS A4 - A0 BITS D10 D9 D8 D7 D6 D5 LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS 10 D4 D3 LVDS CURRENT SETTINGS D0 LVDS current double for data outputs 0 Nominal LVDS current, as set by 1 Double the nominal value D1 LVDS current double for bit and word clock outputs 0 Nominal LVDS current, as set by 1 Double the nominal value D3-D2 LVDS current setting for data outputs 00 3.5 mA 01 4 mA 10 2.5 mA 11 3 mA D5-D4 LVDS current setting for bit and word clock outputs 00 3.5 mA 01 4 mA 10 2.5 mA 11 3 mA 22 Submit Documentation Feedback D2 D1 D0 LVDS CURRENT DOUBLE Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 D10-D6 LVDS internal termination for bit and word clock outputs 00000 No internal termination 00001 166 Ω 00010 200 Ω 00100 250 Ω 01000 333 Ω 10000 500 Ω Any combination of above bits can also be programmed, resulting in a parallel combination of the selected values. For example, 00101 is the parallel combination of 166||250 = 100 Ω 100 Ω 00101 Table 21. Serial Register H REGISTER ADDRESS A4 - A0 11 BITS D10 D9 WORD-WISE CONTROL D8 D7 D6 D5 0 0 0 0 D4 D3 D2 D1 D0 LVDS INTERNAL TERMINATION - DATA OUTPUTS D4-D0 LVDS internal termination for data outputs 00000 No internal termination 00001 166 Ω 00010 200 Ω 00100 250 Ω 01000 333 Ω 10000 500 Ω Any combination of above bits can also be programmed, resulting in a parallel combination of the selected values. For example, 00101 is the parallel combination of 166||250 = 100 Ω 00101 100 Ω D10-D9 Only when 2-wire interface is selected 00 Byte-wise or bit-wise output, 1x frame clock 11 Word-wise output enabled, 0.5x frame clock 01,10 Do not use Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 23 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com PIN CONFIGURATION (2-WIRE INTERFACE) DA0_P DA1_M DA1_P DCLK_M DCLK_P FCLK_M FCLK_P DB0_M DB0_P DB1_M DB1_P 46 45 44 43 42 41 40 39 38 37 LVDD 47 1 DA0_M LGND 48 ADS624x RGZ PACKAGE (TOP VIEW) 36 LVDD 2 35 LGND CAP 3 34 SCLK RESET 4 33 SDATA LVDD 5 32 SEN AGND 6 31 PDNA PAD 24 AGND AVDD 25 23 12 CFG1 AGND 22 INB_P CFG2 26 21 11 CFG3 INA_P 20 INB_M AGND 27 19 10 CLKM INA_M 18 AGND CLKP 28 17 9 AGND AGND 16 AGND CM 29 15 8 CFG4 AGND 14 PDNB NC 30 13 7 AVDD AVDD P0023-05 PIN ASSIGNMENTS (2-WIRE INTERFACE) PINS NAME NO. I/O NO. OF PINS DESCRIPTION SUPPLY AND GROUND PINS AVDD 7,13,24 3 Analog power supply AGND 6,8,9,12,17, 20,25,28,29 9 Analog ground LVDD 2,5,36 3 Digital power supply LGND 1,35 2 Digital ground INPUT PINS CLKP, CLKM 18,19 I 2 Differential input clock pair INA_P, INA_M 11,10 I 2 Differential input signal pair, channel A. If unused, the pins should be tied to VCM. Do not float. INB_P, INB_M 26,27 I 2 Differential input signal pair, channel B. If unused, the pins should be tied to VCM. Do not float. 3 I 1 Connect 2nF capacitor from pin to ground CAP 24 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 PIN ASSIGNMENTS (2-WIRE INTERFACE) (continued) PINS I/O NO. OF PINS DESCRIPTION NAME NO. SCLK 34 I 1 This pin functions as serial interface clock input when RESET is low. When RESET is high, it controls DESKEW, SYNC and global POWER DOWN modes (along with SDATA). See Table 5 for description. This pin has an internal pull-down resistor. SDATA 33 I 1 This pin functions as serial interface data input when RESET is low. When RESET is high, it controls DESKEW, SYNC and global POWER DOWN modes (along with SCLK). See Table 5 for description. This pin has an internal pull-down resistor. SEN 32 I 1 This pin functions as serial interface enable input when RESET is low. When RESET is high, it controls coarse gain and internal/external reference modes. See Table 6 for description. This pin has an internal pull-up resistor. Serial interface reset input. RESET 4 I 1 When using the serial interface mode, the user MUST initialize internal registers through hardware RESET by applying a high-going pulse on this pin or by using software reset option. Refer to the Serial Interface section. In parallel interface mode, tie RESET permanently high. (SCLK, SDATA and SEN function as parallel control pins in this mode). The pin has an internal pull-down resistor to ground. PDNA 31 I 1 Channel A ADC power down control pin. PDNB 30 I 1 Channel B ADC power down control pin. CFG1 23 I 1 Parallel input pin. It controls 1-wire or 2-wire interface and DDR or SDR bit clock selection. See Table 9 for description. Tie to AVDD for 2-wire interface with DDR bit clock. CFG2 22 I 1 Parallel input pin. It controls 12x or 14x serialization and SDR bit clock capture edge. See Table 10 for description. For 12x serialization with DDR bit clock, tie to ground or AVDD. CFG3 21 I 1 RESERVED pin - Tie to ground. CFG4 15 I 1 Parallel input pin. It controls data format and MSB or LSB first modes. See Table 12 for description. VCM 16 IO 1 Internal reference mode – common-mode voltage output External reference mode – reference input. The voltage forced on this pin sets the internal reference. DA0_P,DA0_M 47,48 O 2 Channel A differential LVDS data output pair, wire 0 DA1_P,DA1_M 45,46 O 2 Channel A differential LVDS data output pair, wire 1 DB0_P,DB0_M 39,40 O 2 Channel B differential LVDS data output pair, wire 0 DB1_P,DB1_M 37,38 O 2 Channel B differential LVDS data output pair, wire 1 DCLKP,DCLKM 43,44 O 2 Differential bit clock output pair FCLKP,FCLKM 41,42 O 2 Differential frame clock output pair OUTPUT PINS NC 14 1 Do Not Connect PAD 0 1 Connect to ground using multiple vias. Refer to Board Design Considerations in application section. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 25 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com PIN CONFIGURATION (1-WIRE INTERFACE) UNUSED DA_M DA_P DCLK_M DCLK_P FCLK_M FCLK_P DB_M DB_P UNUSED UNUSED 46 45 44 43 42 41 40 39 38 37 LVDD 47 1 UNUSED LGND 48 ADS624x RGZ PACKAGE (TOP VIEW) 36 LVDD 2 35 LGND CAP 3 34 SCLK RESET 4 33 SDATA LVDD 5 32 SEN AGND 6 31 PDNA PAD 24 AGND AVDD 25 23 12 CFG1 AGND 22 INB_P CFG2 26 21 11 CFG3 INA_P 20 INB_M AGND 27 19 10 CLKM INA_M 18 AGND CLKP 28 17 9 AGND AGND 16 AGND CM 29 15 8 CFG4 AGND 14 PDNB NC 30 13 7 AVDD AVDD P0023-06 PIN ASSIGNMENTS (1-WIRE INTERFACE) PINS NAME NO. I/O NO. OF PINS DESCRIPTION SUPPLY AND GROUND PINS AVDD 7,13,24 3 Analog power supply AGND 6,8,9,12,17, 20,25,28,29 9 Analog ground LVDD 2,5,36 3 Digital power supply LGND 1,35 2 Digital ground INPUT PINS CLKP, CLKM 18,19 I 2 Differential input clock pair INA_P, INA_M 11,10 I 2 Differential input signal pair, channel A. If unused, the pins should be tied to VCM. Do not float. IND_P, IND_M 26,27 I I2 Differential input signal pair, channel B. If unused, the pins should be tied to VCM. Do not float. 3 I 1 Connect 2nF capacitance from pin to ground CAP 26 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 PIN ASSIGNMENTS (1-WIRE INTERFACE) (continued) PINS I/O NO. OF PINS 34 I 1 This pin functions as serial interface clock input when RESET is low. When RESET is high, it controls DESKEW, SYNC and global POWER DOWN modes (along with SDATA). See Table 5 for description. This pin has an internal pull-down resistor. SDATA 33 I 1 This pin functions as serial interface data input when RESET is low. When RESET is high, it controls DESKEW, SYNC and global POWER DOWN modes (along with SCLK). See Table 5 for description. This pin has an internal pull-down resistor. SEN 32 I 1 This pin functions as serial interface enable input when RESET is low. When RESET is high, it controls coarse gain and internal/external reference modes. See Table 6 for description. This pin has an internal pull-up resistor. NAME NO. SCLK DESCRIPTION Serial interface reset input. When using the serial interface mode, the user MUST initialize internal registers through hardware RESET by applying a high-going pulse on this pin or by using software reset option. Refer to the Serial Interface section. In parallel interface mode, tie RESET permanently high. (SCLK, SDATA and SEN function as parallel control pins in this mode). RESET 4 I 1 PDNA 31 I 1 Channel A ADC power down control pin. PDNB 30 I 1 Channel B ADC power down control pin. CFG1 23 I 1 Parallel input pin. It controls 1-wire or 2-wire interface and DDR or SDR bit clock selection. See Table 9 for description. Tie to ground for 1-wire interface with DDR bit clock. CFG2 22 I 1 Parallel input pin. It controls 12x or 14x serialization and SDR bit clock capture edge. See Table 10 for description. For 12x serialization with DDR bit clock, tie to ground or AVDD. CFG3 21 I 1 RESERVED pin - Tie to ground. CFG4 15 I 1 Parallel input pin. It controls data format and MSB or LSB first modes. See Table 12 for description. VCM 16 IO 1 Internal reference mode – common-mode voltage output External reference mode – reference input. The voltage forced on this pin sets the internal reference. DA_P,DA_M 45,46 O 2 Channel A differential LVDS data output pair DB_P,DB_M 39,40 O 2 Channel B differential LVDS data output pair DCLKP,DCLKM 43,44 O 2 Differential bit clock output pair FCLKP,FCLKM 41,42 O 2 Differential frame clock output pair 37,38,47,48 4 These pins are unused in the 1-wire interface. Do not connect NC 14 1 Do not connect PAD 0 1 Connect to ground using multiple vias. Refer to Board Design Considerations in application section. The pin has an internal pull-down resistor to ground. OUTPUT PINS UNUSED Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 27 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) ADS6245 (Fs = 125 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 0 SFDR = 88 dBc SINAD = 74 dBFS SNR = 74.3 dBFS THD = 87.6 dBc −20 −40 Amplitude − dB Amplitude − dB −40 SFDR = 86 dBc SINAD = 72.63 dBFS SNR = 72.76 dBFS THD = 85 dBc −20 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 50 60 f − Frequency − MHz 0 10 20 30 Figure 6. FFT for 230 MHz INPUT SIGNAL G002 0 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –86 dBFS SFDR = –95 dBFS −20 −40 Amplitude − dB −40 Amplitude − dB 60 INTERMODULATION DISTORTION (IMD) vs FREQUENCY SFDR = 77.9 dBc SINAD = 68 dBFS SNR = 69.2 dBFS THD = 75.3 dBc −20 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 50 f − Frequency − MHz 60 0 10 20 30 40 50 f − Frequency − MHz G003 Figure 8. 60 G004 Figure 9. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 75 92 90 74 Gain = 3.5 dB 88 73 86 SNR − dBFS SFDR − dBc 50 Figure 7. 0 84 82 80 Gain = 0 dB 72 71 70 Gain = 3.5 dB 69 78 Gain = 0 dB 76 68 74 67 0 50 100 150 fIN − Input Frequency − MHz 200 250 G005 0 50 100 Submit Documentation Feedback 150 fIN − Input Frequency − MHz Figure 10. 28 40 f − Frequency − MHz G001 200 250 G006 Figure 11. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 75 92 Input adjusted to get −1dBFS input 90 4 dB 5 dB 84 3 dB 82 80 2 dB 3 dB 71 70 69 68 2 dB 78 76 0 dB 67 4 dB 66 1 dB 74 5 dB 6 dB 65 50 70 90 20 110 130 150 170 190 210 230 fIN − Input Frequency − MHz 40 60 80 100 120 140 160 180 200 220 fIN − Input Frequency − MHz G007 Figure 12. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 88 94 82 75 80 74 SNR 78 73 76 72 74 71 3.1 3.2 3.3 3.4 AVDD − Supply Voltage − V 74 90 73 86 72 SFDR 82 78 3.0 70 3.6 3.5 75 fIN = 50.1 MHz AVDD = 3.3 V SNR SFDR − dBc 76 SNR − dBFS SFDR − dBc 77 SFDR 84 72 3.0 98 78 fIN = 50.1 MHz LVDD = 3.3 V 71 3.1 3.2 3.3 PERFORMANCE vs TEMPERATURE 76 80 74 SNR 78 73 76 72 SNR − dBFS SFDR − dBc 75 76 80 70 75 SNR (dBFS) 74 60 73 50 72 40 30 −60 71 T − Temperature − °C 90 77 SFDR (dBFS) SFDR (dBc) fIN = 50.1 MHz 60 78 100 SFDR 82 40 G010 110 SFDR − dBc, dBFS 84 20 70 3.6 PERFORMANCE vs INPUT AMPLITUDE 77 0 3.5 Figure 15. 86 −20 3.4 LVDD − Supply Voltage − V G009 Figure 14. 74 −40 G008 Figure 13. SNR − dBFS 30 80 G011 71 fIN = 20 MHz −50 −40 −30 −20 −10 70 0 Input Amplitude − dBFS Figure 16. Copyright © 2007–2013, Texas Instruments Incorporated SNR − dBFS 10 86 1 dB 72 SINAD − dBFS SFDR − dBc 3.5 dB 73 88 86 0 dB 74 6 dB G012 Figure 17. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 29 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) PERFORMANCE vs CLOCK AMPLITUDE 86 PERFORMANCE vs CLOCK DUTY CYCLE 90 77 78 fIN = 50.1 MHz 84 76 75 80 74 78 73 SNR 76 72 74 71 SFDR − dBc 82 SNR − dBFS SFDR − dBc SFDR 89 77 88 76 87 75 86 SNR − dBFS SFDR 74 SNR 85 73 fIN = 20.1 MHz 72 0.5 1.0 1.5 2.0 70 3.0 2.5 72 35 40 45 50 65 G014 Figure 19. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 1.0 40 0.9 35 RMS (LSB) = 1.064 0.8 30 0.7 0.6 AVDD 0.5 0.4 0.3 LVDD 25 20 15 10 0.2 5 0 0.0 0 25 50 75 100 fS − Sampling Frequency − MSPS 8187 8188 8189 8190 8191 8192 8193 8194 8195 8196 125 G015 Output Code Figure 20. CMRR vs FREQUENCY 78 fIN = 50.1 MHz External Reference Mode 76 74 SNR 88 72 SNR − dBFS 92 SFDR 86 70 84 1.30 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 68 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 90 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 50 100 150 200 f − Frequency − MHz G017 Figure 22. Submit Documentation Feedback G016 Figure 21. 94 SFDR − dBc 60 Input Clock Duty Cycle − % G013 0.1 30 55 Figure 18. Occurence − % PD − Power Dissipation − W Input Clock Amplitude − VPP 84 250 300 G018 Figure 23. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) ADS6244 (Fs = 105 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 91.2 dBc SINAD = 73.9 dBFS SNR = 74.1 dBFS THD = 89.7 dBc −20 SFDR = 81.2 dBc SINAD = 71.6 dBFS SNR = 72.6 dBFS THD = 79.9 dBc −20 −40 Amplitude − dB −40 Amplitude − dB 0 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 50 f − Frequency − MHz 0 10 20 50 G020 Figure 25. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 0 SFDR = 81 dBc SINAD = 68.6 dBFS SNR = 69 dBFS THD = 79 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –88 dBFS SFDR = –89 dBFS −20 −40 Amplitude − dB −40 Amplitude − dB 40 f − Frequency − MHz G019 Figure 24. −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 f − Frequency − MHz 50 0 10 20 30 40 50 f − Frequency − MHz G021 Figure 26. G022 Figure 27. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 92 76 90 75 74 86 SNR − dBFS 88 SFDR − dBc 30 Gain = 3.5 dB 84 82 73 72 Gain = 0 dB 71 70 Gain = 3.5 dB 69 80 68 Gain = 0 dB 78 67 76 66 0 50 100 150 fIN − Input Frequency − MHz 200 250 G023 0 50 100 Figure 28. Copyright © 2007–2013, Texas Instruments Incorporated 150 200 250 fIN − Input Frequency − MHz G024 Figure 29. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 31 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 75 92 Input adjusted to get −1dBFS input 90 88 84 6 dB 80 2 dB 78 69 68 67 66 74 65 30 50 70 90 3 dB 70 76 10 2 dB 71 1 dB 0 dB 1 dB 72 SINAD − dBFS 20 110 130 150 170 190 210 230 fIN − Input Frequency − MHz 4 dB 40 5 dB 60 80 6 dB 100 120 140 160 180 200 220 fIN − Input Frequency − MHz G025 Figure 30. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 88 fIN = 70.1 MHz LVDD = 3.3 V 77 94 75 fIN = 70.1 MHz AVDD = 3.3 V 74 75 80 74 78 73 76 72 SNR 74 SNR 90 86 72 SFDR 82 3.1 3.2 3.3 3.4 78 3.0 70 3.6 3.5 AVDD − Supply Voltage − V 3.1 3.2 84 76 75 80 74 SNR 78 73 76 72 SNR − dBFS SFDR 82 40 T − Temperature − °C 60 110 90 100 85 90 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 30 −60 80 G029 55 fIN = 20 MHz −50 −40 −30 −20 Input Amplitude − dBFS Figure 34. Submit Documentation Feedback G028 40 71 20 70 3.6 SFDR (dBc) fIN = 70.1 MHz 0 3.5 PERFORMANCE vs INPUT AMPLITUDE 77 SFDR − dBc, dBFS PERFORMANCE vs TEMPERATURE −20 3.4 Figure 33. 86 74 −40 3.3 LVDD − Supply Voltage − V G027 Figure 32. SFDR − dBc 71 71 72 3.0 32 73 SNR − dBFS SFDR 82 SFDR − dBc 76 SNR − dBFS 84 SFDR − dBc 98 78 86 G026 Figure 31. SNR − dBFS SFDR − dBc 3 dB 82 3.5 dB 73 5 dB 86 0 dB 74 4 dB −10 50 0 G030 Figure 35. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) PERFORMANCE vs CLOCK AMPLITUDE 92 PERFORMANCE vs CLOCK DUTY CYCLE 93 76 fIN = 70.1 MHz 90 76 fIN = 20.1 MHz 75 91 88 75 SFDR 74 82 71 80 74 SNR 87 70 SFDR 78 1.0 1.5 2.0 85 72 83 68 3.0 2.5 Input Clock Amplitude − VPP 71 35 40 45 50 60 65 Input Clock Duty Cycle − % G031 G032 Figure 37. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 1.0 40 0.9 35 RMS (LSB) = 1.054 0.8 30 0.6 Occurence − % 0.7 AVDD 0.5 0.4 0.3 LVDD 25 20 15 10 0.2 5 0 0.0 0 20 40 60 80 fS − Sampling Frequency − MSPS 8179 8180 8181 8182 8183 8184 8185 8186 8187 8188 100 G033 Output Code Figure 38. CMRR vs FREQUENCY 76 fIN = 70.1 MHz External Reference Mode 74 SNR 82 72 70 SFDR 81 SNR − dBFS 84 68 1.35 1.40 1.45 1.50 1.55 1.60 VVCM − VCM Voltage − V 1.65 66 1.70 G035 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 83 G034 Figure 39. 85 80 1.30 55 Figure 36. 0.1 SFDR − dBc 73 69 76 0.5 PD − Power Dissipation − W 89 SNR − dBFS 72 SFDR − dBc 73 84 SNR − dBFS SFDR − dBc SNR 86 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 50 100 Figure 40. Copyright © 2007–2013, Texas Instruments Incorporated 150 200 250 300 f − Frequency − MHz G018 Figure 41. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 33 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) ADS6243 (Fs = 80 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 91 dBc SINAD = 74.2 dBFS SNR = 74.4 dBFS THD = 88.5 dBc −20 SFDR = 85.7 dBc SINAD = 73 dBFS SNR = 73.5 dBFS THD = 83.9 dBc −20 −40 Amplitude − dB −40 Amplitude − dB 0 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 40 0 10 20 f − Frequency − MHz G037 Figure 42. FFT for 230 MHz INPUT SIGNAL 0 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –93 dBFS SFDR = –98 dBFS −20 −40 Amplitude − dB −40 Amplitude − dB G038 INTERMODULATION DISTORTION (IMD) vs FREQUENCY SFDR = 82 dBc SINAD = 69.4 dBFS SNR = 69.7 dBFS THD = 83.4 dBc −20 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 f − Frequency − MHz 0 10 20 G039 SFDR vs INPUT FREQUENCY G040 SNR vs INPUT FREQUENCY 76 94 75 92 74 SNR − dBFS 90 Gain = 3.5 dB 86 84 82 40 Figure 45. 96 88 30 f − Frequency − MHz Figure 44. SFDR − dBc 40 Figure 43. 0 73 Gain = 0 dB 72 71 Gain = 3.5 dB 70 69 Gain = 0 dB 80 68 78 67 76 66 0 50 100 150 fIN − Input Frequency − MHz 200 250 G041 0 50 100 Submit Documentation Feedback 150 fIN − Input Frequency − MHz Figure 46. 34 30 200 250 G042 Figure 47. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 75 94 Input adjusted to get −1dBFS input 92 5 dB 3 dB 86 84 6 dB 3 dB 72 0 dB 70 69 2 dB 68 80 1 dB 78 67 4 dB 5 dB 66 0 dB 76 30 50 70 90 20 110 130 150 170 190 210 230 fIN − Input Frequency − MHz 40 60 80 100 120 140 160 180 200 220 fIN − Input Frequency − MHz G043 Figure 48. G044 Figure 49. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 94 92 78 fIN = 50.1 MHz LVDD = 3.3 V 91 90 76 SFDR 88 75 86 74 SFDR − dBc 77 SNR − dBFS SFDR − dBc 6 dB 65 10 92 3.5 dB 71 76 fIN = 50.1 MHz AVDD = 3.3 V 75 SNR 90 74 89 73 88 72 SNR − dBFS SFDR − dBc 88 82 1 dB 73 SINAD − dBFS 90 2 dB 74 4 dB SFDR SNR 82 3.0 3.1 3.2 3.3 87 73 3.4 86 3.0 72 3.6 3.5 AVDD − Supply Voltage − V 71 3.1 3.2 3.3 3.5 70 3.6 LVDD − Supply Voltage − V G045 Figure 50. G046 Figure 51. PERFORMANCE vs TEMPERATURE 92 PERFORMANCE vs INPUT AMPLITUDE 110 78 fIN = 50.1 MHz 76 86 75 SNR − dBFS SFDR 88 SNR 84 90 100 77 SFDR − dBc, dBFS 90 SFDR − dBc 3.4 90 85 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 74 SFDR (dBc) 40 82 −40 30 −60 73 −20 0 20 40 60 T − Temperature − °C 80 G047 55 fIN = 20 MHz −50 −40 −30 −20 −10 50 0 Input Amplitude − dBFS Figure 52. Copyright © 2007–2013, Texas Instruments Incorporated SNR − dBFS 84 G048 Figure 53. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 35 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) PERFORMANCE vs CLOCK AMPLITUDE 92 fIN = 50.1 MHz 76 92 77 90 SFDR 86 SNR − dBFS 76 75 84 74 SNR 82 73 80 SFDR − dBc 88 75 SFDR 88 74 86 73 SNR 72 84 78 1.0 1.5 2.0 fIN = 20.1 MHz 70 3.0 2.5 82 35 Input Clock Amplitude − VPP 40 45 50 POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 40 0.9 35 RMS (LSB) = 1.016 0.8 30 0.7 0.6 AVDD 0.5 0.4 0.3 25 20 15 10 LVDD 0.2 5 0 0.0 0 20 40 60 8180 8181 8182 8183 8184 8185 8186 8187 8188 8189 80 fS − Sampling Frequency − MSPS G051 Output Code Figure 56. CMRR vs FREQUENCY 76 fIN = 50.1 MHz External Reference Mode 74 SNR 72 SFDR 90 70 88 SNR − dBFS 94 68 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 66 1.70 G053 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 92 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 50 100 150 200 f − Frequency − MHz Figure 58. Submit Documentation Feedback G052 Figure 57. 96 SFDR − dBc G050 Figure 55. 0.1 36 71 65 60 Input Clock Duty Cycle − % G049 1.0 86 1.30 55 Figure 54. Occurence − % PD − Power Dissipation − W 72 71 76 0.5 SNR − dBFS 90 SFDR − dBc PERFORMANCE vs CLOCK DUTY CYCLE 78 250 300 G018 Figure 59. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) ADS6242 (Fs = 65 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 92.4 dBc SINAD = 74.3 dBFS SNR = 74.5 dBFS THD = 90 dBc −20 −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 0 10 20 f − Frequency − MHz G055 G056 Figure 61. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 SFDR = 82.1 dBc SINAD = 69.3 dBFS SNR = 69.7 dBFS THD = 81.2 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –96 dBFS SFDR = –86 dBFS −20 −40 Amplitude − dB −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 0 10 20 G057 G058 Figure 63. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 96 76 94 75 92 74 SNR − dBFS 90 88 30 f − Frequency − MHz Figure 62. SFDR − dBc 30 Figure 60. 0 Amplitude − dB SFDR = 88.8 dBc SINAD = 73.6 dBFS SNR = 73.9 dBFS THD = 86.6 dBc −20 Amplitude − dB −40 Amplitude − dB 0 Gain = 3.5 dB 86 84 Gain = 0 dB 73 72 71 Gain = 3.5 dB 70 82 80 69 Gain = 0 dB 68 78 76 67 0 50 100 150 fIN − Input Frequency − MHz 200 250 G059 0 50 100 Figure 64. Copyright © 2007–2013, Texas Instruments Incorporated 150 200 250 fIN − Input Frequency − MHz G060 Figure 65. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 37 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 96 75 Input adjusted to get −1dBFS input 94 74 90 3 dB 4 dB 88 86 84 6 dB 82 3.5 dB 2 dB 72 3 dB 70 69 68 1 dB 67 2 dB 78 4 dB 5 dB 66 0 dB 76 6 dB 65 30 50 70 90 110 130 150 170 190 210 230 fIN − Input Frequency − MHz 20 40 60 80 100 120 140 160 180 200 220 fIN − Input Frequency − MHz G061 Figure 66. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 94 92 78 fIN = 50.1 MHz LVDD = 3.3 V 91 88 75 86 74 SFDR − dBc 76 SFDR SNR − dBFS 77 90 G062 Figure 67. 76 fIN = 50.1 MHz AVDD = 3.3 V 75 SNR 90 74 89 73 SFDR 88 72 SNR − dBFS 10 SFDR − dBc 0 dB 71 80 92 1 dB 73 5 dB SINAD − dBFS SFDR − dBc 92 SNR 84 87 73 3.1 3.2 3.3 3.4 86 3.0 72 3.6 3.5 AVDD − Supply Voltage − V 3.1 3.2 PERFORMANCE vs TEMPERATURE 90 76 88 75 SNR − dBFS 77 SNR 86 90 100 SFDR − dBc, dBFS 92 90 85 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 SFDR (dBc) 74 40 55 fIN = 50.1 MHz 73 0 20 40 T − Temperature − °C 60 30 −60 80 G065 fIN = 20 MHz −50 −40 Submit Documentation Feedback −30 −20 Input Amplitude − dBFS Figure 70. 38 G064 110 78 SFDR −20 70 3.6 PERFORMANCE vs INPUT AMPLITUDE 79 84 −40 3.5 Figure 69. 96 SFDR − dBc 3.4 LVDD − Supply Voltage − V G063 Figure 68. 94 3.3 SNR − dBFS 82 3.0 71 −10 50 0 G066 Figure 71. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) PERFORMANCE vs CLOCK AMPLITUDE 96 PERFORMANCE vs CLOCK DUTY CYCLE 95 80 fIN = 50.1 MHz 79 93 75 78 77 SFDR 88 76 86 75 SFDR − dBc 90 SFDR SNR − dBFS SFDR − dBc 92 91 SNR − dBFS 94 76 74 89 73 SNR 84 74 SNR 82 80 0.5 1.0 1.5 2.0 72 fIN = 20.1 MHz 85 72 3.0 2.5 Input Clock Amplitude − VPP 71 35 40 45 50 60 65 Input Clock Duty Cycle − % G067 G068 Figure 73. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 1.0 40 0.9 35 RMS (LSB) = 1.027 0.8 30 0.7 0.6 0.5 AVDD 0.4 0.3 25 20 15 10 LVDD 0.2 5 0.1 0 0.0 0 10 20 30 40 50 fS − Sampling Frequency − MSPS 8189 8190 8191 8192 8193 8194 8195 8196 8197 60 G069 Output Code Figure 74. CMRR vs FREQUENCY 76 fIN = 50.1 MHz External Reference Mode 94 74 92 72 90 70 SFDR 88 SNR − dBFS SNR 68 1.35 1.40 1.45 1.50 1.55 1.60 VVCM − VCM Voltage − V 1.65 66 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 86 1.30 G070 Figure 75. 96 SFDR − dBc 55 Figure 72. Occurence − % PD − Power Dissipation − W 87 73 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 50 100 200 250 300 G071 Figure 76. Copyright © 2007–2013, Texas Instruments Incorporated 150 f − Frequency − MHz G018 Figure 77. Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 39 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) Contour Plots across Input and Sampling Frequencies 125 120 92 89 80 86 83 fS - Sampling Frequency - MSPS 110 65 86 80 83 89 74 100 77 83 90 86 80 86 83 80 70 68 71 74 86 89 80 60 68 71 77 65 83 50 89 86 30 10 50 74 80 83 150 100 68 71 77 40 200 250 300 65 400 350 450 500 fIN - Input Frequency - MHz 65 75 70 80 85 90 SFDR - dBc M0049-13 Figure 78. SFDR Contour (no gain) 125 120 85 88 70 76 82 110 fS - Sampling Frequency - MSPS 79 91 91 88 88 100 73 79 85 94 82 90 76 82 88 80 70 91 70 79 85 60 67 73 88 76 50 70 82 40 91 30 10 79 85 50 100 150 200 73 76 250 300 350 400 450 500 fIN - Input Frequency - MHz 65 70 75 80 85 SFDR - dBc 90 M0049-14 Figure 79. SFDR Contour (3.5 dB coarse gain) 40 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TYPICAL CHARACTERISTICS (continued) All plots are at 25°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain 32K point FFT (unless otherwise noted) 125 120 68 fS - Sampling Frequency - MSPS 73 74 110 64 67 72 70 71 65 66 69 100 90 66 68 80 70 72 73 74 71 64 65 67 69 70 60 66 64 65 50 67 40 30 10 50 69 71 70 72 73 74 150 100 68 66 200 250 64 65 300 63 400 350 62 450 500 fIN - Input Frequency - MHz 60 70 65 75 SNR - dBFS M0048-13 Figure 80. SNR Contour (no gain) 125 120 72 71 fS - Sampling Frequency - MSPS 110 70 67 68 69 66 65 100 90 67 71 80 68 72 70 70 65 69 64 66 60 50 71 67 72 69 40 30 10 50 100 150 66 68 70 200 250 64 65 64 300 63 62 63 400 350 61 450 500 fIN - Input Frequency - MHz 60 62 64 66 68 70 SNR - dBFS 72 M0048-14 Figure 81. SNR Contour (3.5 dB coarse gain) Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 41 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com APPLICATION INFORMATION THEORY OF OPERATION The ADS6245/ADS6244/ADS6243 (ADS624X) is a family of dual channel, 14-bit pipeline ADC based on switched capacitor architecture in CMOS technology. The conversion is initiated simultaneously by all the four channels at the rising edge of the external input clock. After the input signals are captured by the sample and hold circuit of each channel, the samples are sequentially converted by a series of low resolution stages. The stage outputs are combined in a digital correction logic block to form the final 14-bit word with a latency of 12 clock cycles. The 14-bit word of each channel is serialized and output as LVDS levels. In addition to the data streams, a bit clock and frame clock are also output. The frame clock is aligned with the 14-bit word boundary. ANALOG INPUT The analog input consists of a switched-capacitor based differential sample and hold architecture, shown in Figure 82. This differential topology results in very good AC performance even for high input frequencies. The INP and INM pins have to be externally biased around a common-mode voltage of 1.5 V, available on VCM pin 13. For a full-scale differential input, each input pin INP, INM has to swing symmetrically between VCM + 0.5 V and VCM – 0.5 V, resulting in a 2-Vpp differential input swing. The maximum swing is determined by the internal reference voltages REFP (2.0V nominal) and REFM (1.0 V, nominal). The sampling circuit has a 3 dB bandwidth that extends up to 500 MHz (Figure 83, shown by the transfer function from the analog input pins to the voltage across the sampling capacitors, TF_ADC). Sampling Switch Lpkg 3 nH 25 W Sampling Capacitor RCR Filter INP Cbond 2 pF 50 W Resr 200 W Lpkg 3 nH 3.2 pF Cpar2 Ron 1 pF 15 W Cpar1 0.8 pF Ron 10 W 50 W Ron 15 W 25 W INM Cpar2 1 pF Cbond 2 pF Resr 200 W Csamp 4.0 pF Csamp 4.0 pF Sampling Capacitor Sampling Switch S0237-01 Figure 82. Input Sampling Circuit 42 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 1 Magnitude − dB 0 −1 −2 −3 −4 −5 −6 0 100 200 300 400 500 fIN − Input Frequency − MHz 600 700 G073 Figure 83. Analog Input Bandwidth (represented by magnitude of TF_ADC, see Figure 85 ) Drive Circuit Requirements For optimum performance, the analog inputs must be driven differentially. This improves the common-mode noise immunity and even order harmonic rejection. A 5-Ω resistor in series with each input pin is recommended to damp out ringing caused by the package parasitics. It is also necessary to present low impedance (< 50 Ω) for the common mode switching currents. For example, this is achieved by using two resistors from each input terminated to the common mode voltage (VCM). In addition to the above, the drive circuit may have to be designed to provide a low insertion loss over the desired frequency range and matched impedance to the source. While doing this, the ADC input impedance has to be taken into account. Figure 84 shows that the impedance (Zin, looking into the ADC input pins) decreases at high input frequencies. The smith chart shows that the input impedance is capacitive and can be approximated by a series R-C upto 500 MHz. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 43 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com F1 Freq = 50 MHz S(1, 1) = 0.967 / –13.241 Impedance = 62.211 – j421.739 1000 F1 Frequency = 50 MHz Mag(Zin1) = 426.302 900 700 F2 Frequency = 400 MHz Mag(Zin1) = 65.193 600 F1 500 S(1, 1) Magnitude of Zin -- W 800 400 F2 300 200 F1 F2 100 0 0 50 100 150 200 250 300 350 400 450 500 fI -- Input Frequency -- MHz Frequency (100 kHz to 500 MHz) F2 Freq = 400 MHz S(1, 1) = 0.273 / –59.329 Impedance = 58.132 – j29.510 M0087-01 Figure 84. ADC Input Impedance, Zin Using RF-Transformer Based Drive Circuits Figure 85 shows a configuration using a single 1:1 turns ratio transformer (for example, Coilcraft WBC1-1) that can be used for low input frequencies (about 100MHz). The single-ended signal is fed to the primary winding of the RF transformer. The transformer is terminated on the secondary side. Putting the termination on the secondary side helps to shield the kickbacks caused by the sampling circuit from the RF transformer’s leakage inductances. The termination is accomplished by two resistors connected in series, with the center point connected to the 1.5 V common mode (VCM pin). The value of the termination resistors (connected to common mode) has to be low (< 100 Ω) to provide a low-impedance path for the ADC common-mode switching current. 44 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 TF_ADC 0.1 mF ADS6xxx 5W INP 0.1 mF 25 W 25 W INM 5W 1:1 VCM S0256-01 Figure 85. Single Transformer Drive Circuit At high input frequencies, the mismatch in the transformer parasitic capacitance (between the windings) results in degraded even-order harmonic performance. Connecting two identical RF transformers back-to-back helps minimize this mismatch, and good performance is obtained for high frequency input signals. Figure 86 shows an example using two transformers (Coilcraft WBC1-1). An additional termination resistor pair (enclosed within the shaded box in Figure 86) may be required between the two transformers to improve the balance between the P and M sides. The center point of this termination must be connected to ground. ADS6xxx 0.1 mF 5W INP 50 W 0.1 mF 50 W 50 W 50 W INM 1:1 1:1 5W VCM S0164-04 Figure 86. Two Transformer Drive Circuit Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 45 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Using Differential Amplifier Drive Circuits Figure 87 shows a drive ciruit using a differential amplifier (TI's THS4509) to convert a single-ended input to differential output that can be interfaced to the ADC input pins. In addition to the single-ended to differential conversion, the amplifier also provides gain (10dB in Figure 87). As shown in the figure, RIN helps to isolate the amplifier output from the switching inputs of the ADC. Together with CIN, it also forms a low-pass filter that bandlimits the noise (and signal) at the ADC input. As the amplifier outputs are ac-coupled, the common-mode voltage of the ADC input spins is set using two resistors connected to VCM. The amplifier outputs can also be dc-coupled. Using the output common-mode control of the THS4509, the ADC input pins can be biased to 1.5V. In this case, use +4 V and -1 V supplies for the THS4509 to ensure its output common-mode voltage (1.5V) is at mid-supply. RF +VS 500 W 0.1 mF RS 0.1 mF 10 mF RFIL 0.1 mF 5W INP RG 0.1 mF RT CFIL 200 W CFIL 200 W CM THS4509 RG RFIL INM 5W 0.1 mF 500 W RS || RT VCM 0.1 mF –VS ADS6xxx 0.1 mF 10 mF 0.1 mF RF S0259-01 Figure 87. Drive Circuit using THS4509 Refer to the EVM User Guide (SLAU196) for more information. INPUT COMMON MODE To ensure a low-noise common-mode reference, the VCM pin is filtered with a 0.1-μF low-inductance capacitor connected to ground. The VCM pin is designed to directly drive the ADC inputs. The input stage of the ADC sinks a common-mode current in the order of 155 μA at 125 MSPS (per input pin). Equation 1 describes the dependency of the common-mode current and the sampling frequency. 155 mAxFs 125 MSPS (1) This equation helps to design the output capability and impedance of the CM driving circuit accordingly. REFERENCE The ADS624X has built-in internal references REFP and REFM, requiring no external components. Design schemes are used to linearize the converter load seen by the references; this and the on-chip integration of the requisite reference capacitors eliminates the need for external decoupling. The full-scale input range of the converter can be controlled in the external reference mode as explained below. The internal or external reference modes can be selected by programming the register bit (Table 14). 46 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 INTREF Internal Reference VCM 1 kW INTREF 4 kW EXTREF REFM REFP ADS6xxx S0165-04 Figure 88. Reference Section Internal Reference When the device is in internal reference mode, the REFP and REFM voltages are generated internally. Commonmode voltage (1.5 V nominal) is output on VCM pin, which can be used to externally bias the analog input pins. External Reference When the device is in external reference mode, the VCM acts as a reference input pin. The voltage forced on the VCM pin is buffered and gained by 1.33 internally, generating the REFP and REFM voltages. The differential input voltage corresponding to full-scale is given by Equation 2. Full−scale differential input pp + (Voltage forced on VCM) 1.33 (2) In this mode, the range of voltage applied on VCM should be 1.45 V to 1.55 V. The 1.5-V common-mode voltage to bias the input pins has to be generated externally. COARSE GAIN AND PROGRAMMABLE FINE GAIN ADS624X includes gain settings that can be used to get improved SFDR performance (compared to 0 dB gain mode). The gain settings are 3.5 dB coarse gain and programmable fine gain from 0 dB to 6 dB. For each gain setting, the analog input full-scale range scales proportionally, as shown in Table 22. The coarse gain is a fixed setting of 3.5 dB and is designed to improve SFDR with little degradation in SNR. The fine gain is programmable in 1 dB steps from 0 to 6 dB. With fine gain also, SFDR improvement is achieved, but at the expense of SNR (there is about 1dB SNR degradation for every 1dB of fine gain). Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 47 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com So, the fine gain can be used to trade-off between SFDR and SNR. The coarse gain makes it possible to get best SFDR but without losing SNR significantly. At high input frequencies, the gains are especially useful as the SFDR improvement is significant with marginal degradation in SINAD. The gains can be programmed using the register bits (Table 19) and (Table 18). Note that the default gain after reset is 0 dB. Table 22. Full-Scale Range Across Gains GAIN, dB TYPE FULL-SCALE, Vpp 0 Default (after reset) 2 3.5 Coarse setting (fixed) 1.34 1 1.78 2 1.59 3 1.42 Fine setting (programmable) 4 1.26 5 1.12 6 1.00 CLOCK INPUT The ADS624X clock inputs can be driven differentially (SINE, LVPECL or LVDS) or single-ended (LVCMOS), with little or no difference in performance between them. The common-mode voltage of the clock inputs is set to VCM using internal 5-kΩ resistors as shown in Figure 89. This allows using transformer-coupled drive circuits for sine wave clock or ac-coupling for LVPECL, LVDS clock sources (see Figure 91 and Figure 93). Figure 90 shows the impedance looking into the clock input pins of the device. 48 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Clock Buffer Lpkg » 3 nH 10 W CLKP Cbond » 1 pF Ceq Ceq 5 kW Resr » 100 W VCM 6 pF 5 kW Lpkg » 3 nH 10 W CLKM Cbond » 1 pF Resr » 100 W Ceq » 1 to 3 pF, equivalent input capacitance of clock buffer S0275-01 Figure 89. Internal Clock Buffer 1000 Impedance (Magnitude) − Ω 900 800 700 600 500 400 300 200 100 0 0 25 50 75 100 125 Clock Frequency − MHz G082 Figure 90. Clock Buffer Input Impedance Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 49 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 0.1 mF CLKP Differential Sine-Wave or PECL or LVDS Clock Input 0.1 mF CLKM ADS6xxx S0167-05 Figure 91. Differential Clock Driving Circuit Figure 92 shows a typical scheme using PECL clock drive from a CDCM7005 clock driver. SNR performance with this scheme is comparable with that of a low jitter sine wave clock source. VCC Reference Clock REF_IN VCC Y0 CLKP Y0B CLKM CDCM7005 VCXO_INP OUTM VCXO_INM CP_OUT ADS6xxx VCXO OUTP CTRL S0238-02 Figure 92. PECL Clock Drive Using CDCM7005 Single-ended CMOS clock can be ac-coupled to the CLKP input, with CLKM (pin) connected to ground with a 0.1-μF capacitor, as shown in Figure 93. 0.1 mF CMOS Clock Input CLKP 0.1 mF CLKM ADS6xxx S0168-07 Figure 93. Single-Ended Clock Driving Circuit 50 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 For best performance, the clock inputs have to be driven differentially, reducing susceptibility to common-mode noise. For high input frequency sampling, it is recommended to use a clock source with very low jitter. Bandpass filtering of the clock source can help reduce the effect of jitter. There is no change in performance with a non50% duty cycle clock input. CLOCK BUFFER GAIN When using a sinusoidal clock input, the noise contributed by clock jitter improves as the clock amplitude is increased. Hence, it is recommended to use large clock amplitude. Use clock amplitude greater than 1V pp to avoid performance degradation. In addition, the clock buffer has programmable gain to amplify the input clock to support very low clock amplitude. The gain can be set by programming the register bits (Table 15) and increases monotonically from Gain 0 to Gain 5 settings. Table 23 shows the minimum clock amplitude supported for each gain setting. Table 23. Minimum Clock Amplitude across gains CLOCK BUFFER GAIN MINIMUM CLOCK AMPLITUDE SUPPORTED, mV pp differential Gain 0 (Minimum gain) 800 Gain 1 (default gain) 400 Gain 2 300 Gain 3 200 Gain 4 150 Gain 5 (Highest gain) 100 POWER DOWN MODES The ADS624X has three power down modes – global power down, channel standby and input clock stop. Global Power Down This is a global power down mode in which almost the entire chip is powered down, including the four ADCs, internal references, PLL and LVDS buffers. As a result, the total power dissipation falls to about 77 mW typical (with input clock running). This mode can be initiated by setting the register bit (Table 14). The output data and clock buffers are in high impedance state. The wake-up time from this mode to data becoming valid in normal mode is 100 μs. Channel Standby In this mode, only the ADC of each channel is powered down and this helps to get very fast wake-up times. Each of the four ADCs can be powered down independently using the register bits (Table 14). The output LVDS buffers remain powered up. The wake-up time from this mode to data becoming valid in normal mode is 200 clock cycles. Input Clock Stop The converter enters this mode: • If the input clock frequency falls below 1 MSPS or • If the input clock amplitude is less than 400 mV (pp, differential with default clock buffer gain setting) at any sampling frequency. All ADCs and LVDS buffers are powered down and the power dissipation is about 235 mW. The wake-up time from this mode to data becoming valid in normal mode is 100 μs. Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 51 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Table 24. Power Down Modes Summary (1) (1) POWER DOWN MODE AVDD POWER (mW) LVDD POWER (mW) WAKE UP TIME In power-up 782 208 – Global power down 65 12 100 μs 1 Channel in standby 510 208 200 Clocks 2 Channels in standby 235 208 200 Clocks Input clock stop 200 35 100 μs Sampling frequency = 125 MSPS. POWER SUPPLY SEQUENCING During power-up, the AVDD and LVDD supplies can come up in any sequence. The two supplies are separated inside the device. Externally, they can be driven from separate supplies or from a single supply. 52 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 DIGITAL OUTPUT INTERFACE The ADS624X offers several flexible output options making it easy to interface to an ASIC or an FPGA. Each of these options can be easily programmed using either parallel pins or the serial interface. The output interface options are: • 1-wire, 1× frame clock, 14× and 16× serialization with DDR bit clock • 2-wire, 1× frame clock, 16× serialization, with DDR and SDR bit clock, byte wise/bit wise/word wise • 2-wire, 1× frame clock, 14× serialization, with SDR bit clock, byte wise/bit wise/word wise • 2-wire, (0.5 x) frame clock, 14× serialization, with DDR bit clock, byte wise/bit wise/word wise. The maximum sampling frequency, bit clock frequency and output data rate will vary depending on the interface options selected (refer to Table 12). Table 25. Maximum Recommended Sampling Frequency for Different Output Interface Options INTERFACE OPTIONS MAXIMUM RECOMMENDED SAMPLING FREQUENCY, MSPS BIT CLOCK FREQUENCY, MHZ FRAME CLOCK FREQUENCY, MHZ SERIAL DATA RATE, Mbps 1-Wire DDR Bit clock 14× Serialization 65 455 65 910 16× Serialization 65 520 65 1040 2-Wire DDR Bit clock 14× Serialization 125 437.5 62.5 875 16× Serialization 125 500 125 1000 2-Wire SDR Bit clock 14× Serialization 65 455 65 910 16× Serialization 65 520 65 1040 Each interface option is described in detail below. 1-WIRE INTERFACE – 14× AND 16× SERIALIZATION WITH DDR BIT CLOCK Here the device outputs the data of each ADC serially on a single LVDS pair (1-wire). The data is available at the rising and falling edges of the bit clock (DDR bit clock). The ADC outputs a new word at the rising edge of every frame clock, starting with the MSB. Optionally, it can also be programmed to output the LSB first. The data rate is 14 × Sample frequency (14× serialization) and 16 × Sample frequency (16× serialization). Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 53 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Input Clock, CLKP/M Freq = Fs 16-Bit Serialization (1) 12-Bit Serialization Frame Clock, FCLKP Freq = 1 ´ Fs Bit Clock – DDR, DCLKP/M Freq = 7 ´ Fs Output Data DA, DB, DC, DD Data Rate = 14 ´ Fs D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D8 (D7) D7 (D8) D5 (D8) D4 (D9) D3 D2 D1 D0 (D10) (D11) (D12) (D13) D13 (D0) D12 (D1) Bit Clock – DDR, DCLKP/M Freq = 8 ´ Fs Output Data DA, DB, DC, DD Data Rate = 16 ´ Fs 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D6 D5 D4 D3 D2 (D9) (D10) (D11) (D12) (D13) D1 (0) Sample N D0 (0) 0 (D0) 0 (D1) Sample N + 1 Data Bit in MSB First Mode D13 (D2) Data Bit in LSB First Mode (1) In 16-Bit serialization, two zero bits are padded to the 14-bit ADC data on the MSB side. T0225-02 Figure 94. 1-Wire Interface 2-WIRE INTERFACE – 16× SERIALIZATION WITH DDR/SDR BIT CLOCK The 2-wire interface is recommended for sampling frequencies above 65 MSPS. In 16× serialization, two zero bits are padded to the 14-bit ADC data on the MSB side and the combined 16-bit data is serialized and output over two LVDS pairs. The data rate is 8 × Sample frequency since 8 bits are sent on each wire every clock cycle. The data is available along with DDR bit clock or optionally with SDR bit clock. Each ADC sample is sent over the 2 wires as byte-wise or bit-wise or word-wise. Using the 16× serialization makes it possible to upgrade to a 16-bit ADC in the future seamlessly, without requiring any modification to the receiver capture logic design. 54 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Input Clock, CLKP/M Freq = Fs Frame Clock, FCLKP/M Freq = 1 ´ Fs Bit Clock – SDR, DCLKP/M Freq = 8 ´ Fs In Byte-Wise Mode Bit Clock – DDR, DCLKP/M Freq = 4 ´ Fs Output Data DA0, DB0, DC0, DD0 D7 (D0) D6 (D1) D5 (D2) D4 (D3) D3 (D4) D2 (D5) D1 (D6) D0 (D7) D7 (D0) D6 (D1) D5 (D2) D4 (D3) D3 (D4) D2 (D5) D1 (D6) D0 (D7) Output Data DA1, DB1, DC1, DD1 0 (D8) 0 (D9) D13 D12 D11 D10 D9 (0) D8 (0) 0 (D8) 0 (D9) D13 D12 D11 D10 (D10) (D11) (D12) (D13) (D10) (D11) (D12) (D13) D9 (0) D8 (0) D0 (0) 0 (D0) D12 (D2) D10 (D4) D8 (D6) D6 (D8) D2 D0 (D10) (D12) D1 (0) 0 (D1) D13 (D3) D11 (D5) D9 (D7) D7 (D9) (D11) (D13) D5 D4 D3 In Word-Wise Mode In Bit-Wise Mode Data Rate = 8 ´ Fs Output Data DA0, DB0, DC0, DD0 0 (D0) D12 (D2) D10 (D4) D8 (D6) D6 (D8) (D10) (D12) Output Data DA1, DB1, DC1, DD1 0 (D1) D13 (D3) D11 (D5) D9 (D7) D7 (D9) (D11) (D13) Output Data DA0, DB0, DC0, DD0 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D8 (D7) D7 (D8) D6 (D9) (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D8 (D7) D7 (D8) D6 (D9) (D10) (D11) (D12) (D13) D4 D5 Data Bit in MSB First Mode D2 D3 D5 D4 D3 D4 D5 D2 D2 D3 (0) D1 (0) D1 (0) D0 (0) D1 (0) D0 (0) White Cells – Sample N D13 (D3) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0226-02 Figure 95. 2-Wire Interface 16× Serialization Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 55 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 2-WIRE INTERFACE - 14× SERIALIZATION The 14-bit ADC data is serialized and output over two LVDS pairs. A frame clock at 1× sample frequency is also available with an SDR bit clock. With DDR bit clock option, the frame clock frequency is 0.5× sample frequency. The output data rate will be 7 × Sample frequency as 7 data bits are output every clock cycle on each wire. Each ADC sample is sent over the 2 wires as byte-wise or bit-wise or word-wise. 56 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Input Clock, CLK Freq = Fs Frame Clock, FCLK Freq = 1 ´ Fs In Byte-Wise Mode Bit Clock – SDR, DCLK Freq = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) Output Data DA1, DB1, DC1, DD1 D13 (D7) D12 (D8) D11 (D9) D10 D9 D8 D7 D13 (D7) D12 (D8) D11 (D9) D10 D9 (D10) (D11) (D12) (D13) (D10) (D11) D8 (0) D7 (0) D13 (D7) D12 (D8) D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 D0 (D10) (D12) D12 (D0) D10 (D2) (D11) (D13) D13 (D1) D11 (D3) D13 (D0) D12 (D1) D13 (D0) D12 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) (D12) Output Data DA1, DB1, DC1, DD1 D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) (D13) D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) (D12) (D13) D2 D3 D0 D1 D3 D2 D3 D1 D1 D1 D0 D0 White Cells – Sample N Data Bit in MSB First Mode D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0227-02 Figure 96. 2-Wire Interface 14× Serialization - SDR Bit Clock Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 57 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Input Clock, CLK Freq = Fs Frame Clock, FCLK Freq = 0.5 ´ Fs In Byte-Wise Mode Bit Clock – DDR, DCLK Freq = 3.5 ´ Fs Output Data DA0, DB0, DC0, DD0 D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) Output Data DA1, DB1, DC1, DD1 D13 (D7) D12 (D8) D11 (D9) D10 D9 D8 (0) D7 (0) D13 (D7) D12 (D8) D11 (D9) D10 D9 (D10) (D11) (D10) (D11) D8 (0) D7 (0) D13 (D7) D12 (D8) D2 D0 (0) D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 D0 (D10) (D12) D12 (D0) D10 (D2) (D11) (D13) D13 (D1) D11 (D3) 0 (D0) 0 (D1) D13 (D0) D12 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) Output Data DA1, DB1, DC1, DD1 D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) D1 (0) D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) (D12) (D13) D3 D3 D2 D3 D1 D1 D1 D0 D0 White Cells – Sample N Data Bit in MSB First Mode D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0228-02 A. In the byte-wise and bit-wise modes, the frame clock frequency is 1 x Fs. In the word-wise mode, the frame clock frequency is 0.5 x Fs Figure 97. 2-Wire interface 14× Serialization - DDR Bit Clock 58 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 OUTPUT BIT ORDER In the 2-wire interface, three types of bit order are supported - byte-wise, bit-wise and word-wise. Byte-wise: Each 14-bit sample is split across the 2 wires. Wires DA0 and DB0 carry the 7 LSB bits D6-D0 and wires DA1 and DB1 carry the 7 MSB bits. Bit-wise: Each 14-bit sample is split across the 2 wires. Wires DA0 and DB0 carry the 7 even bits (D0,D2,D4..) and wires DA1 and DB1 carry the 7 odd bits (D1,D3,D5...). Word-wise: In this case, all 14-bits of a sample are sent over a single wire. Successive samples are sent over the 2 wires. For example sample N is sent on wires DA0 and DB0 while sample N+1 is sent over wires DA1 and DB1. The frame clock frequency is 0.5x sampling frequency, with the rising edge aligned with the start of each word. MSB/LSB FIRST By default after reset, the 14-bit ADC data is output serially with the MSB first (D13, D12, D11,...D1,D0). The data can be output LSB first also by programming the register bit . In the 2-wire mode, the bit order in each wire is flipped in the LSB first mode. OUTPUT DATA FORMATS Two output data formats are supported – 2s complement (default after reset) and offset binary. They can be selected using the serial interface register bit . In the event of an input voltage overdrive, the digital outputs go to the appropriate full-scale level. For a positive overdrive, the output code is 0x3FFF in offset binary output format, and 0x1FFF in 2s complement output format. For a negative input overdrive, the output code is 0x0000 in offset binary output format and 0x2000 in 2s complement output format. LVDS CURRENT CONTROL The default LVDS buffer current is 3.5 mA. With an external 100-Ω termination resistance, this develops ±350mV logic levels at the receiver. The LVDS buffer currents can also be programmed to 2.5 mA, 3.0 mA and 4.5 mA using the register bits . In addition, there exists a current double mode, where the LVDS nominal current is doubled (register bits , Table 20). LVDS INTERNAL TERMINATION An internal termination option is available (using the serial interface), by which the LVDS buffers are differentially terminated inside the device. Five termination resistances are available – 166, 200, 250, 333, and 500 Ω (nominal with ±20% variation). Any combination of these terminations can be programmed; the effective termination will be the parallel combination of the selected resistances. The terminations can be programmed separately for the clock and data buffers (bits and , Table 21). The internal termination helps to absorb any reflections from the receiver end, improving the signal integrity. This makes it possible to drive up to 10 pF of load capacitance, compared to only 5 pF without the internal termination.Figure 98 and Figure 99 show the eye diagram with 5 pF and 10 pF load capacitors (connected from each output pin to ground). With 100-Ω internal and 100-Ω external termination, the voltage swing at the receiver end will be halved (compared to no internal termination). The voltage swing can be restored by using the LVDS current double mode (bits , Table 20). Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 59 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com C001 Figure 98. LVDS Data Eye Diagram with 5-pF Load Capacitance (No Internal Termination) C002 Figure 99. LVDS Data Eye Diagram with 10-pF Load Capacitance (100 Ω Internal Termination) 60 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 CAPTURE TEST PATTERNS ADS624X outputs the bit clock (DCLK), positioned nearly at the center of the data transitions. It is recommended to route the bit clock, frame clock and output data lines with minimum relative skew on the PCB. This ensures sufficient setup/hold times for a reliable capture by the receiver. The DESKEW is a 1010... or 0101... pattern output on the serial data lines that can be used to verify if the receiver capture clock edge is positioned correctly. This may be useful in case there is some skew between DCLK and serial data inside the receiver. Once deserialized, it is required to ensure that the parallel data is aligned to the frame boundary. The SYNC test pattern can be used for this. For example, in the 1-wire interface, the SYNC pattern is 7 '1's followed by 7 '0's (from MSB to LSB). This information can be used by the receiver logic to shift the deserialized data till it matches the SYNC pattern. In addition to DESKEW and SYNC, the ADS624X includes other test patterns to verify correctness of the capture by the receiver such as all zeros, all ones and toggle. These patterns are output on all four channel data lines simultaneously. Some patterns like custom and sync are affected by the type of interface selected, serialization and bit order. Table 26. Test Patterns PATTERN DESCRIPTION All zeros Outputs logic low. All ones Outputs logic high. Toggle Outputs toggle pattern - alternates between 10101010101010 and 01010101010101 every clock cycle. Custom Outputs a 14-bit custom pattern. The 14-bit custom pattern can be specified into two serial interface registers. In the 2-wire interface, each code is sent over the 2 wires depending on the serialization and bit order. Sync Deskew Outputs a sync pattern. Outputs deskew pattern. Either = 10101010101010 OR = 01010101010101 every clock cycle. Table 27. SYNC Pattern INTERFACE OPTION SERIALIZATION 1-Wire 2-Wire Copyright © 2007–2013, Texas Instruments Incorporated SYNC PATTERN ON EACH WIRE 14 X MSB-11111110000000-LSB 16 X MSB-111111111000000000-LSB 14 X MSB-1111000-LSB 16 X MSB-11110000-LSB Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 61 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com OUTPUT TIMINGS AT LOWER SAMPLING FREQUENCIES Setup, hold and other timing parameters are specified across sampling frequencies and for each type of output interface in the tables below. Table 29 to Table 32: Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, CL = 5 pF, IO = 3.5 mA, RL = 100 Ω, no internal termination, unless otherwise noted. Timing parameters are ensured by design and characterization and not tested in production. Ts = 1/ Sampling frequency = 1/Fs Table 28. Clock Propagation Delay for different interface options INTERFACE SERIALIZATION CLOCK PROPAGATION DELAY, tpd_clk 14x tpd_clk = 0.428xTs + tdelay 16x tpd_clk = 0.375xTs + tdelay 1-wire with DDR bit clock 2-wire with DDR bit clock 2 (when tpd_clk ≥ Ts) 1 (when tpd_clk < Ts) tpd_clk = 0.428xTs + tdelay 2-wire with DDR bit clock 0 1 (when tpd_clk ≥ Ts) tpd_clk = 0.75xTs + tdelay 16x 2-wire with SDR bit clock (1) 0 tpd_clk = 0.857xTs + tdelay 14x 2-wire with SDR bit clock (1) SERIALIZER LATENCY clock cycles 0 (when tpd_clk < Ts) tpd_clk = 0.375xTs + tdelay 0 Note that the total latency = ADC latency + internal serializer latency. The ADC latency is 12 clock cycles. Table 29. Timings for 1-Wire Interface SERIALIZATION 14× DATA SETUP TIME, tsu ns SAMPLING FREQUENCY MSPS MAX DATA HOLD TIME, th ns MIN TYP MIN TYP 65 0.3 0.5 0.4 0.6 40 0.65 0.85 0.7 0.9 20 1.3 1.65 1.6 1.9 10 3.2 3.5 3.2 3.6 MAX tdelay ns MIN TYP MAX Fs ≥ 40 MSPS 3 4 5 Fs < 40 MSPS 3 4.5 6 Fs ≥ 40 MSPS 16× 65 0.22 0.42 0.35 3 0.55 3 62 Submit Documentation Feedback 4 5 Fs < 40 MSPS 4.5 6 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 Table 30. Timings for 2-Wire Interface, DDR Bit Clock SERIALIZATION DATA SETUP TIME, tsu ns SAMPLING FREQUENCY MSPS 14× 16× MIN TYP 105 0.45 92 0.55 80 DATA HOLD TIME, th ns MAX MIN TYP 0.65 0.5 0.7 0.75 0.6 0.8 0.65 0.85 0.7 0.9 65 0.8 1.1 0.8 1.1 40 1.4 1.7 1.5 1.9 105 0.35 0.55 0.4 0.6 92 0.45 0.65 0.5 0.7 80 0.55 0.75 0.6 0.8 65 0.6 0.9 0.7 1 40 1.1 1.4 1.3 1.7 MAX tdelay ns MIN TYP MAX Fs ≥ 45 MSPS 3.4 4.4 5.4 Fs < 45 MSPS 3.7 5.2 6.7 Fs ≥ 45 MSPS 3.4 4.4 5.4 Fs < 45 MSPS 3.7 5.2 6.7 Table 31. Timings for 2-Wire Interface, SDR Bit Clock SERIALIZATION DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 65 0.8 1 1 1.2 40 1.5 1.7 1.6 1.8 20 3.4 3.6 3.3 3.5 10 6.9 7.2 6.6 6.9 65 0.65 0.85 0.8 1.0 40 1.3 1.5 1.4 1.6 20 2.8 3.0 2.8 3.0 10 6.0 6.3 5.8 6.1 14× 16× MAX tdelay ns MAX MIN TYP MAX Fs ≥ 40 MSPS 3.4 4.4 5.4 Fs < 40 MSPS 3.7 5.2 6.7 Fs ≥ 40 MSPS 3.4 4.4 5.4 Fs < 40 MSPS 3.7 5.2 6.7 Table 32. Output Jitter (applies to all interface options) SAMPLING FREQUENCY MSPS BIT CLOCK JITTER, CYCLE-CYCLE ps, peak-peak MIN ≥ 65 TYP MAX FRAME CLOCK JITTER, CYCLE-CYCLE ps, peak-peak MIN TYP 350 Copyright © 2007–2013, Texas Instruments Incorporated MAX 75 Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 63 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com BOARD DESIGN CONSIDERATIONS Grounding A single ground plane is sufficient to give optimum performance, provided the analog, digital and clock sections of the board are cleanly partitioned. Refer to the EVM User Guide (SLAU196) for more layout details. Supply Decoupling As the ADS624X already includes internal decoupling, minimal external decoupling can be used without loss in performance. Note that the decoupling capacitors can help to filter external power supply noise, so the optimum number of decoupling capacitors would depend on actual application. It is recommended to use separate supplies for the analog and digital supply pins to isolate digital switching noise from sensitive analog circuitry. In case only a single 3.3V supply is available, it should be routed first to AVDD. It can then be tapped and isolated with a ferrite bead (or inductor) with decoupling capacitor, before being routed to LVDD. Exposed Thermal Pad For best thermal performance, it is necessary to solder the exposed pad at the bottom of the package to a ground plane using multiple vias. For detailed information, see application notes QFN Layout Guidelines (SLOA122A) and QFN/SON PCB Attachment (SLUA271A). 64 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 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 LSBs. Integral Nonlinearity (INL) – The INL is the deviation of the ADC's transfer function from a best fit line determined by a least squares curve fit of that transfer function, measured in units of LSBs. Gain Error – The gain error is the deviation of the ADC's 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 – The offset error is the difference, given in number of LSBs, between the ADC's actual average idle channel output code and the ideal average idle channel output code. This quantity is often mapped into mV. Temperature Drift – The temperature drift coefficient (with respect to gain error and offset error) specifies the change per degree Celsius of the parameter from TMIN to TMAX. It is calculated by dividing the maximum deviation of the parameter across the TMIN to TMAX range by the difference TMAX–TMIN. Signal-to-Noise Ratio – 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 nine harmonics. P SNR + 10Log10 S PN (3) 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 fullscale 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. PS SINAD + 10Log10 PN ) PD (4) 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 fullscale range. Effective Number of Bits (ENOB) – The ENOB is a measure of a converter’s performance as compared to the theoretical limit based on quantization noise. ENOB + SINAD * 1.76 6.02 (5) Total Harmonic Distortion (THD) – THD is the ratio of the power of the fundamental (PS) to the power of the first nine harmonics (PD). P THD + 10Log10 S PD (6) THD is typically given in units of dBc (dB to carrier). Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 65 ADS6245, ADS6244 ADS6243, ADS6242 SLAS542B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Spurious-Free Dynamic Range (SFDR) – The ratio of the power of the fundamental to the highest other spectral component (either spur or harmonic). SFDR 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 and 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. DC Power Supply Rejection Ratio (DC PSRR) – The DC PSSR is the ratio of the change in offset error to a change in analog supply voltage. The DC PSRR is typically given in units of mV/V. AC Power Supply Rejection Ratio (AC PSRR) – AC PSRR is the measure of rejection of variations in the supply voltage by the ADC. If ΔVsup is the change in supply voltage and ΔVout is the resultant change of the ADC output code (referred to the input), then PSRR + 20Log10 DVout , expressed in dBc DVsup (7) Voltage Overload Recovery – The number of clock cycles taken to recover to less than 1% error after an overload on the analog inputs. This is tested by separately applying a sine wave signal with 6dB positive and negative overload. The deviation of the first few samples after the overload (from their expected values) is noted. Common Mode Rejection Ratio (CMRR) – CMRR is the measure of rejection of variations in the analog input common-mode by the ADC. If ΔVcm_in is the change in the common-mode voltage of the input pins and ΔVout is the resultant change of the ADC output code (referred to the input), then CMRR + 20Log10 DVout , expressed in dBc DVcm_in (8) Cross-Talk (only for multi-channel ADC)– This is a measure of the internal coupling of a signal from adjacent channel into the channel of interest. It is specified separately for coupling from the immediate neighbouring channel (near-channel) and for coupling from channel across the package (far-channel). It is usually measured by applying a full-scale signal in the adjacent channel. Cross-talk is the ratio of the power of the coupling signal (as measured at the output of the channel of interest) to the power of the signal applied at the adjacent channel input. It is typically expressed in dBc. 66 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 ADS6245, ADS6244 ADS6243, ADS6242 www.ti.com SLAS542B – MAY 2007 – REVISED DECEMBER 2013 REVISION HISTORY Changes from Revision A (July 2007) to Revision B Page • Added Frame setup time and Frame hold time to the TIMING SPECIFICATIONS table .................................................... 9 • Changed Figure 2 ............................................................................................................................................................... 12 • Changed text in the USING PARALLEL INTERFACE CONTROL ONLY section From: "The parallel pins can be configured using a simple resistor string" To: "The parallel pins can be configured using a simple resistor string (with 10% tolerance resistors)" .................................................................................................................................................... 13 • Changed Figure 3 ............................................................................................................................................................... 14 • Changed Table 9 ................................................................................................................................................................ 15 • Changed Table 10 .............................................................................................................................................................. 15 • Changed Table 12 .............................................................................................................................................................. 15 • Added Note 3 to Table 13 ................................................................................................................................................... 18 • Added note to the DESCRIPTION OF SERIAL REGISTERS - “After a hardware or software reset, all register bits are cleared to ‘0’" ................................................................................................................................................................ 19 • Added 32K point FFT to TYPICAL CHARACTERISTICS test conditions .......................................................................... 28 • Added Gain 5 setting to CLOCK BUFFER GAIN section ................................................................................................... 51 • Added Note A to Figure 97 ................................................................................................................................................. 58 Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: ADS6245 ADS6244 ADS6243 ADS6242 67 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) ADS6242IRGZT ACTIVE VQFN RGZ 48 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6242 ADS6243IRGZT ACTIVE VQFN RGZ 48 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6243 ADS6244IRGZR ACTIVE VQFN RGZ 48 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6244 ADS6244IRGZT ACTIVE VQFN RGZ 48 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6244 ADS6245IRGZR ACTIVE VQFN RGZ 48 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6245 ADS6245IRGZT ACTIVE VQFN RGZ 48 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6245 (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