ADS6423IRGCR

ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 QUAD CHANNEL, 12-BIT, 105/80/65 MSPS ADC WITH SERIAL LVDS INTERFACE Check for Samples: ADS6424, ADS6423, ADS6422 FEATURES • • • • APPLICATIONS 1 • • • • • • • 12-Bit Resolution With No Missing Codes Simultaneous Sample and Hold 3.5dB Coarse Gain and upto 6dB 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 64 QFN Package (9 mm × 9 mm) Pin Compatible 14-Bit Family (ADS644X SLAS531A) Feature Compatible Dual Channel Family (ADS624X - SLAS542A, ADS622X - SLAS543A) • • • • Base-station IF Receivers Diversity Receivers Medical Imaging Test Equipment Table 1. ADS64XX Quad Channel Family 125 MSPS 105 MSPS 80 MSPS 65 MSPS ADS644X 14 Bit ADS6445 ADS6444 ADS6443 ADS6442 ADS642X 12 Bit ADS6425 (SLWS197) ADS6424 ADS6423 ADS6422 Table 2. Performance Summary SFDR, dBc SINAD, dBFS Fin = 10MHz (0 dB gain) Fin = 170MHz (3.5 dB gain) ADS6425 ADS6424 ADS6423 ADS6422 90 91 91 93 79 81 82 83 Fin = 10MHz (0 dB gain) 70.7 71.1 71.3 71.3 Fin = 170MHz (3.5 dB gain) 67.4 68.1 68.2 68.7 420 340 300 265 Power per channel, mW DESCRIPTION The ADS6424/ADS6423/ADS6422 (ADS642X) is a family of high performance 12-bit 105/80/65 MSPS quad channel A-D converters. Serial LVDS data outputs reduce the number of interface lines, resulting in a compact 64-pin QFN package (9 mm × 9 mm) that allows for high system integration density. The device includes 3.5dB 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 ADS642X 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 12-bit data from each channel. In addition to the serial data streams, the frame and bit clocks are also transmitted as LVDS outputs. The LVDS output buffers have features such as programmable LVDS currents, current doubling modes and internal termination options. These can be used to widen eyeopenings 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. 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 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com LVDD LGND CAP AVDD AGND ADS642X 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 12-Bit ADC Digital Encoder and Serializer 12-Bit ADC Digital Encoder and Serializer SHA 12-Bit ADC Digital Encoder and Serializer SHA 12-Bit ADC Digital Encoder and Serializer INA_P SHA INA_M INB_P SHA INB_M INC_P INC_M IND_P VCM DA1_P DA1_M DB0_P DB0_M DB1_P DB1_M DC0_P DC0_M DC1_P DC1_M DD0_P DD0_M DD1_P DD1_M REFM REFP IND_M DA0_P DA0_M Reference Parallel Interface Serial Interface 2 Submit Documentation Feedback SCLK RESET SEN SDATA CFG4 CFG3 CFG1 CFG2 PDN ADS642x B0199-04 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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. PACKAGE/ORDERING INFORMATION (1) PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ADS6424 QFN-64 (2) RGC –40°C to 85°C AZ6424 ADS6423 QFN-64 (2) RGC –40°C to 85°C AZ6423 ADS6422 QFN-64 (2) RGC –40°C to 85°C AZ6422 (1) (2) ORDERING NUMBER TRANSPORT MEDIA, QUANTITY ADS6424IRGCT 250, Tape/reel ADS6424IRGCR 2000, Tape/reel ADS6423IRGCT 250, Tape/reel ADS6423IRGCR 2000, Tape/reel ADS6422IRGCT 250, Tape/reel ADS6422IRGCR 2000, 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 125 °C Tstg Storage temperature range –65 to 150 °C (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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 3 ADS6424 ADS6423 ADS6422 SLAS532B – 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 ADS6424 5 105 ADS6423 5 80 ADS6422 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 Input clock duty cycle MSPS 3.3 35% 50% 65% DIGITAL OUTPUTS 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 4 Submit Documentation Feedback Without internal termination 5 With internal termination pF 10 100 –40 Ω 85 °C Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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). ADS6424 Fs = 105 MSPS PARAMETER MIN RESOLUTION TYP ADS6423 Fs = 80 MSPS MAX MIN TYP ADS6422 Fs = 65 MSPS MAX MIN TYP UNIT MAX 12 12 12 Bits 2.0 2.0 2.0 VPP 7 7 7 pF Analog input bandwidth 500 500 500 MHz Analog input common mode current (per input pin of each ADC) 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 V VREFT Internal reference top voltage 2.0 2.0 2.0 V ΔVREF Internal reference error, (VREFT–VREFB) VCM Common mode output voltage 1.5 1.5 1.5 V VCM output current capability ±4 ±4 ±4 mA -15 ±2 15 -15 ±2 15 -15 ±2 15 mV DC ACCURACY No missing codes EO Offset error, across devices and across channels within a device Specified –15 Offset error temperature coefficient, across devices and across channels within a device ±2 Specified 15 –15 0.05 ±2 Specified 15 –15 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 ±0.1 0.75 -0.75 0.0125 Gain error of channel alone, across devices and across channels within a device (1) –1 Channel gain error temperature coefficient, across devices and across channels within a device ±0.3 ±0.1 0.75 -0.75 0.0125 1 –1 0.005 ±0.3 ±0.1 0.75 Δ%/°C 0.0125 1 –1 0.005 ±0.3 % FS 1 % FS Δ%/°C 0.005 DNL Differential nonlinearity –0.9 ±0.5 2.0 –0.9 ±0.4 1.8 –0.9 ±0.4 1.8 INL Integral nonlinearity –2.2 ±1.25 2.2 –2.0 ±1.25 2.0 –2.0 ±1.0 2.0 PSRR DC power supply rejection ratio LSB LSB 0.5 0.5 0.5 mV/V 410 360 320 mA POWER SUPPLY ICC (1) Total supply current This is specified by design and characterization; it is not tested in production. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 5 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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 ADS6424 Fs = 105 MSPS MIN TYP ADS6423 Fs = 80 MSPS MAX MIN TYP ADS6422 Fs = 65 MSPS MAX MIN TYP IAVDD Analog supply current 322 280 245 ILVDD LVDS supply current 88 80 75 Total power Power down (with input clock stopped) 6 Submit Documentation Feedback UNIT MAX mA mA 1.35 1.55 1.18 1.35 1.05 1.25 W 77 150 77 150 77 150 mW Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 TEST CONDITIONS ADS6424 Fs = 105 MSPS MIN TYP MAX ADS6423 Fs = 80 MSPS MIN TYP ADS6422 Fs = 65 MSPS MAX MIN UNIT TYP MAX DYNAMIC AC CHARACTERISTICS Fin = 10 MHz 71.2 Fin = 50 MHz 70.8 Fin = 70 MHz 67.5 Fin = 100 MHz SNR Signal to noise ratio Fin = 170 MHz Fin = 230 MHz 71 70.5 69 69.1 3.5 dB Coarse gain 68.4 68.4 68.8 0 dB gain 67.8 66.9 68.1 3.5 dB Coarse gain 67.3 67.3 67.8 71.1 71.3 71.3 69.8 67 67.5 70.9 70 70.6 67.5 71 70 70.1 70 68.5 68.6 68.9 3.5 dB Coarse gain 68.1 68.2 68.7 0 dB gain 66.8 66.5 67.3 3.5 dB Coarse gain 66.8 67.2 67.4 Inputs tied to common-mode 0.407 0.407 0.407 Fin = 10 MHz 91 91 93 Fin = 50 MHz 80 73 Fin = 230 MHz 87 76 86 86 85 85 83 0 dB gain 78 79 80 3.5 dB Coarse gain 81 82 83 0 dB gain 76 77 78 3.5 dB Coarse gain 79 80 81 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 dBFS LSB 88 81 Fin = 100 MHz Fin = 170 MHz 76 dBFS 70.7 0 dB gain Fin = 70 MHz SFDR Spurious free dynamic range 70.9 70.5 Fin = 100 MHz RMS Output noise 71.2 70.6 68.8 Fin = 70 MHz Fin = 230 MHz 71.4 68 70.1 Fin = 50 MHz Fin = 170 MHz 71.1 0 dB gain Fin = 10 MHz SINAD Signal to noise and distortion ratio 71.4 68 Submit Documentation Feedback dBc 7 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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 TEST CONDITIONS ADS6424 Fs = 105 MSPS MIN Fin = 10 MHz 94 Fin = 50 MHz 88 Fin = 70 MHz 73 Fin = 170 MHz Fin = 230 MHz MAX MIN 96 76 90 97 76 92 92 87 0 dB gain 84 86 86 3.5 dB Coarse gain 86 88 88 0 dB gain 81 82 83 3.5 dB Coarse gain 83 84 85 91 Fin = 50 MHz 80 73 91 76 87 88 86 86 85 85 83 0 dB gain 78 79 80 3.5 dB Coarse gain 82 82 83 0 dB gain 76 77 78 3.5 dB Coarse gain 79 80 81 Fin = 10 MHz 95 96 98 Fin = 50 MHz 94 95 95 Fin = 70 MHz 94 95 95 Fin = 100 MHz 92 93 93 Fin = 170 MHz 89 90 90 Fin = 230 MHz 86 87 87 Fin = 10 MHz 89.5 89.5 Fin = 50 MHz 78.5 Fin = 70 MHz 74 85.5 84 83 80.5 Fin = 170 MHz 76 77.5 78.5 Fin = 230 MHz 74 75.5 Fin = 50 MHz IMD 2-Tone intermodulation distortion F1= 46.09 MHz, F2 = 50.09 MHz 90 94 97.5 F1= 185.09 MHz, F2 = 190.09 MHz 88 92 96 8 Fin = 70 MHz Submit Documentation Feedback dBc 76.5 ENOB Effective number of bits 10.8 dBc 86 70 11.5 dBc 91 74 Fin = 100 MHz 10.9 dBc 93 76 81 Fin = 170 MHz UNIT TYP MAX 87 Fin = 10 MHz Fin = 230 MHz THD Total harmonic distortion TYP 90 Fin = 100 MHz Worst harmonic (other than HD2, HD3) MIN 90 Fin = 70 MHz HD3 Third harmonic MAX ADS6422 Fs = 65 MSPS 88 Fin = 100 MHz HD2 Second harmonic TYP ADS6423 Fs = 80 MSPS 10.9 11.5 Bits 11.4 dBFS Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 TEST CONDITIONS ADS6424 Fs = 105 MSPS MIN Cross-talk TYP MAX ADS6423 Fs = 80 MSPS MIN TYP ADS6422 Fs = 65 MSPS MAX MIN Near channel Cross-talk signal frequency = 10 MHz 92 94 100 Far channel Cross-talk signal frequency = 10 MHz 105 106 108 1 1 1 35 35 35 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 UNIT TYP MAX dBc Clock cycles dBc 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 = 100 Ω (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 4 pF 1375 mV Input capacitance DIGITAL OUTPUTS High-level output voltage Low-level output voltage 1025 |VOD| Output differential voltage VOS Output offset voltage Common-mode voltage of OUTP and OUTM Output capacitance Output capacitance inside the device, from either output to ground (1) 250 350 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. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 9 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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. TEST CONDITIONS PARAMETER tJ Aperture jitter ADS6424 Fs = 105 MSPS MIN Uncertainty in the sampling instant TYP ADS6423 Fs = 80 MSPS MAX MIN 250 ADS6422 Fs = 65 MSPS TYP MAX MIN 250 TYP UNIT MAX 250 fs rms Interface: 2-wire, DDR bit clock, 14x serialization Data setup time (4) From data crossover to bit clock cross-over 0.45 0.65 0.65 0.85 0.8 1.1 ns Data hold time (4) (5) (6) From bit clock cross-over to data cross-over 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 0.45 0.65 0.65 0.85 0.8 1.1 ns th Frame hold time From bit clock falling edge crossover to frame clock falling edge crossover 0.5 0.7 0.7 0.9 0.8 1.1 ns tpd_clk Input clock rising Clock edge cross-over to propagation delay frame clock rising (6) edge cross-over 3.4 4.4 3.4 4.4 3.4 4.4 tsu (5) (6) th tsu Bit clock cyclecycle jitter (5) Frame clock cycle-cycle jitter (5) 5.4 5.4 5.4 ns 350 350 350 ps pp 75 75 75 ps pp Below specifications apply for 5 MSPS ≤ Sampling freq ≤ 105 MSPS and all interface options tA Aperture delay Delay from input clock rising edge to the actual sampling instant 1 2 3 1 2 3 1 2 3 ns Aperture delay variation Channel-channel within same device –250 ±80 250 –250 ±80 250 –250 ±80 250 ps ADC Latency (1) (2) (3) (4) (5) (6) (7) 10 (7) Time for a sample to propagate to ADC outputs, see Figure 1 12 12 12 Clock cycles 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. Note that the total latency = ADC latency + internal serializer latency. The serializer latency depends on the interface option selected as listed in Table 27. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 Wake up time TEST CONDITIONS ADS6424 Fs = 105 MSPS MIN TYP ADS6423 Fs = 80 MSPS MAX MIN ADS6422 Fs = 65 MSPS TYP MAX MIN TYP UNIT MAX Time to valid data after coming out of global power down 100 100 100 μs Time to valid data after input clock is re-started 100 100 100 μs Time to valid data after coming out of channel standby 200 200 200 clock cycles tRISE Data rise time From –100 mV to +100 mV 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 ps tRISE Bit clock and Frame clock rise time From –100 mV to +100 mV 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 ps Bit clock duty cycle 45% 50% 55% 45% 50% 55% 45% 50% 55% Frame clock duty cycle 47% 50% 53% 47% 50% 53% 47% 50% 53% Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 11 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 D11 D10 D9 Sample N–1 Frame Clock D8 D7 D6 D5 D4 D3 D2 D1 D0 DOM Sample N FCLKM FCLKP T0105-03 Figure 1. Latency 12 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 13 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com DEVICE PROGRAMMING MODES ADS642X 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 (refer to 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, PDN, 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 (refer to Table 5 to Table 8) 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 lists descriptions of the modes controlled by the parallel pins. Table 3. Parallel Pin Definition PIN SEN SCLK, SDATA CONTROL FUNCTIONS Coarse gain and internal/external reference. Sync, deskew patterns and global power down. PDN Dedicated pin for global power down CFG1 1-Wire/2-wire and DDR/SDR bit clock CFG2 12x/14x 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 and PDN) 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 and PDN) can also be used to configure the device. The parallel interface control pins CFG1 to CFG4 and PDN are available. After power-up, the device will automatically get configured as per the parallel pin voltage settings (refer to Table 5 to Table 11) 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 (refer to Table 4). 14 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Table 4. Priority Between Parallel Pins and Serial Registers FUNCTIONS SUPPORTED PIN PRIORITY As described in Table 8 to Table 11 Register bits can control the modes only if the register bit is high. If is low, then the control voltage on these parallel pins determines the function. PDN Global Power Down Register bit controls global power down only if PDN pin is low. If PDN is high, device is in global power down mode. SEN Serial Interface Enable CFG1 to CFG4 Coarse gain setting is controlled by bit only if the bit is high. Else, it is in default setting of 0 dB gain. Internal/External reference setting is determined by bit . SCLK, SDATA Serial Interface Clock Register bits control the sync and deskew output patterns. and Serial Interface Data Power down is determined by bit . pins LVDD LVDD (5/6) LVDD R (5/8) LVDD GND 2R (5/8) LVDD 3R (5/6) LVDD 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 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 15 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com DESCRIPTION OF PARALLEL PINS Table 5. SCLK, SDATA Control Pins SCLK SDATA DESCRIPTION LOW LOW NORMAL conversion. 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 DESCRIPTION External reference and 0 dB coarse gain (full-scale = 2 VPP) (3/8)LVDD External reference and 3.5 dB coarse gain (full-scale = 1.34 VPP) (5/8)LVDD Internal reference and 3.5 dB coarse gain (full-scale = 1.34 VPP) LVDD Internal reference and 0 dB coarse gain (full-scale = 2 VPP) Independent of the programming mode used, after power-up the parallel pins PDN, CFG1 to CFG4 will automatically configure the device as per the voltage applied (refer to Table 7 to Table 11). Table 7. PDN Control Pin PDN 0 AVDD DESCRIPTION Normal operation Power down global Table 8. 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 9. CFG2 Control Pin CFG2 DESCRIPTION 0 (default) + 200mV 12x Serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (3/6) LVDD ± 200mV 14x Serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (5/6) LVDD ± 200mV 14x Serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) LVDD - 200mV 12x Serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) Table 10. CFG3 Control Pin CFG3 16 RESERVED - TIE TO GROUND Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Table 11. 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 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 10 ns) 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. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 17 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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 18 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 = 3.3 V, 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 = 3.3 V, 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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 19 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com SERIAL REGISTER MAP Table 12. 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) 20 0 D5 INTERNAL OR EXTERNAL D4 D3 POWER DOWN CH D POWER DOWN CHC D2 POWER DOWN CH B INPUT CLOCK BUFFER GAIN CONTROL TEST PATTERNS 0 0 0 D1 D0 POWER DOWN CH A 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 0 0 0 0 CUSTOM PATTERN (MSB BIT) BYTE-WISE OR BITWISE MSB OR LSB FIRST COURSE GAIN ENABLE FALLING OR RISING BIT CLOCK CAPTURE EDGE 0 12-BIT OR 14-BIT SERIALIZE DDR OR SDR BIT CLOCK 1-WIRE OR 2-WIRE INTERFACE LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS WORD-WISE CONTROL 0 0 LVDS CURRENT SETTINGS 0 0 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: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 DESCRIPTION OF SERIAL REGISTERS Note: After a hardware or software reset, all register bits are cleared to ‘0’. Table 13. Serial Register A REGISTER ADDRESS A4 - A0 00 BITS D10 S/W RESET D9 0 D8 D7 0 0 D6 D5 0 INTERNAL OR EXTERNAL D4 POWER DOWN CH D D3 POWER DOWN CHC D2 POWER DOWN CH B D1 D0 POWER DOWN CH A 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 D1 0 CH A Powered up 1 CH A ADC Powered down D2 0 CH B Powered up 1 CH B ADC Powered down D3 0 CH C Powered up 1 CH C ADC Powered down D4 0 CH D Powered up 1 CH D 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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 21 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Table 14. Serial Register B REGISTER ADDRESS A4 - A0 04 BITS D10 0 D9 0 D8 D7 0 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 gain after reset 01100 Gain 2 01010 Gain 3 01001 Gain 4 01000 Gain 5, maximum gain D1 D0 0 0 Table 15. 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 22 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Table 16. Serial Register D REGISTER ADDRESS A4 - A0 BITS D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 D2 D1 D0 CUSTOM PATTERN (LOWER 11 BITS) 0B D10 - D0 Lower 11 bits of custom pattern … Table 17. Serial Register E REGISTER ADDRESS A4 - A0 0C BITS D10 D9 D8 D7 FINE GAIN CONTROL (1 dB to 6 dB) D6 0 D5 0 D4 0 0 D4 - D0 MSB bit 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) D3 0 0 0 CUSTOM PATTERN (MSB BIT) Table 18. Serial Register F REGISTER ADDRESS A4 - A0 0D BITS D10 OVER-RIDE BITE D9 D8 0 D7 BYTE-WISE OR BITWISE 0 D6 MSB OR LSB FIRST D5 D4 D3 D2 D1 D0 COARSE 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 selection 0 12x Serialization 1 14x Serialization D4 Bit clock capture edge (only when SDR bit clock is selected, D1 = 1) 0 Capture data with falling edge of bit clock Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 23 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 1 Capture data with rising edge of bit clock D5 Coarse gain control 0 0 dB coarse gain 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 19. Serial Register G REGISTER ADDRESS A4 - A0 BITS D10 D9 D8 D7 D6 D5 LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS 10 D4 D3 D2 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 D10-D6 LVDS internal termination for bit and word clock outputs 00000 No internal termination 00001 166 Ω 24 Submit Documentation Feedback D1 D0 LVDS CURRENT DOUBLE Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 20. 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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 25 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com PIN CONFIGURATION (2-WIRE INTERFACE) LVDD DC1_P DC1_M DC0_P DC0_M LGND FCLKP FCLKM DCLKP DCLKM LGND DB1_P DB1_M DB0_P DB0_M LVDD ADS642x RGC PACKAGE (TOP VIEW) DA1_P 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 1 DD0_M DA1_M 2 47 DD0_P DA0_P 3 46 DD1_M DA0_M 4 45 DD1_P CAP 5 44 SCLK RESET 6 43 SDATA LVDD 7 42 SEN AGND 8 41 PDN PAD IND_P AGND 13 36 AGND INB_M 14 35 INC_M INB_P 15 34 INC_P AGND 33 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 AGND AVDD AVDD 37 AGND 12 CFG1 INA_P CFG2 IND_M CFG3 38 AVDD 11 AGND INA_M CLKM AGND CLKP 39 AGND 10 VCM AGND CFG4 AVDD NC 40 AGND 9 AVDD AVDD P0056-06 PIN ASSIGNMENTS (2-WIRE INTERFACE) PINS NAME NO. I/O NO. OF PINS DESCRIPTION SUPPLY AND GROUND PINS AVDD 9,17,19,27,32 ,40 6 Analog power supply AGND 8,10,13,16, 18, 23, 26, 31,33,36,39 11 Analog ground LVDD 7,49,64 3 Digital power supply LGND 54,59 2 Digital ground INPUT PINS CLKP, CLKM 24,25 I 2 Differential input clock pair INA_P, INA_M 12,11 I 2 Differential input signal pair, channel A. If unused, the pins should be tied to VCM. Do not float. INB_P, INB_M 15,14 I 2 Differential input signal pair, channel B. If unused, the pins should be tied to VCM. Do not float. 26 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 PIN ASSIGNMENTS (2-WIRE INTERFACE) (continued) PINS NAME NO. I/O NO. OF PINS DESCRIPTION INC_P, INC_M 34,35 I 2 Differential input signal pair, channel C. If unused, the pins should be tied to VCM. Do not float. IND_P, IND_M 37,38 I 2 Differential input signal pair, channel D. If unused, the pins should be tied to VCM. Do not float. 1 Connect 2-nF capacitor from pin to ground CAP 5 SCLK 44 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). Refer to Table 5 for description. This pin has an internal pull-down resistor. SDATA 43 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). Refer to Table 5 for description. This pin has an internal pull-down resistor. SEN 42 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. Refer to Table 6 for description. This pin has an internal pull-up resistor. 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 6 I 1 PDN 41 I 1 Global power down control pin. CFG1 30 I 1 Parallel input pin. It controls 1-wire or 2-wire interface and DDR or SDR bit clock selection. Refer to Table 8 for description. Tie to AVDD for 2-wire interface with DDR bit clock. CFG2 29 I 1 Parallel input pin. It controls 12x or 14x serialization and SDR bit clock capture edge. Refer to Table 9 for description. For 12x serialization with DDR bit clock, tie to ground or AVDD. CFG3 28 I 1 RESERVED pin - TIE to ground. CFG4 21 I 1 Parallel input pin. It controls data format and MSB or LSB first modes. Refer to Table 11 for description. VCM 22 I/O 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 3,4 O 2 Channel A differential LVDS data output pair, wire 0 DA1_P,DA1_M 1,2 O 2 Channel A differential LVDS data output pair, wire 1 DB0_P,DB0_M 62,63 O 2 Channel B differential LVDS data output pair, wire 0 DB1_P,DB1_M 60,61 O 2 Channel B differential LVDS data output pair, wire 1 DC0_P,DC0_M 52,53 O 2 Channel C differential LVDS data output pair, wire 0 DC1_P,DC1_M 50,51 O 2 Channel C differential LVDS data output pair, wire 1 DD0_P,DD0_M 47,48 O 2 Channel D differential LVDS data output pair, wire 0 DD1_P,DD1_M 45,46 O 2 Channel D differential LVDS data output pair, wire 1 DCLKP,DCLKM 57,58 O 2 Differential bit clock output pair FCLKP,FCLKM 55,56 O 2 Differential frame clock output pair The pin has an internal pull-down resistor to ground. OUTPUT PINS NC 20 1 Do Not Connect PAD 0 1 Connect to ground plane using multiple vias. See Board Design Considerations in application section. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 27 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com PIN CONFIGURATION (1-WIRE INTERFACE) LVDD DD_P DD_M DC_P DC_M LGND FCLKP FCLKM DCLKP DCLKM LGND DB_P DB_M DA_P LVDD DA_M ADS642x RGC PACKAGE (TOP VIEW) UNUSED 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 1 UNUSED UNUSED 2 47 UNUSED UNUSED 3 46 UNUSED UNUSED 4 45 UNUSED CAP 5 44 SCLK RESET 6 43 SDATA LVDD 7 42 SEN AGND 8 41 PDN PAD IND_P AGND 13 36 AGND INB_M 14 35 INC_M INB_P 15 34 INC_P AGND 33 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 AGND AVDD AVDD 37 AGND 12 CFG1 INA_P CFG2 IND_M CFG3 38 AVDD 11 AGND INA_M CLKM AGND CLKP 39 AGND 10 VCM AGND CFG4 AVDD NC 40 AVDD 9 AGND AVDD P0056-07 PIN ASSIGNMENTS (1-WIRE INTERFACE) PINS NAME NO. I/O NO. OF PINS DESCRIPTION SUPPLY AND GROUND PINS AVDD 9,17,19,27,32,40, 6 Analog power supply AGND 8,10,13,16,18,23, 26,31,33,36,39, 11 Analog ground LVDD 7,49,64 3 Digital power supply LGND 54,59 2 Digital ground INPUT PINS CLKP, CLKM 24,25 I 2 Differential input clock pair INA_P, INA_M 12,11 I 2 Differential input signal pair, channel A. If unused, the pins should be tied to VCM. Do not float. INB_P, INB_M 15,14 I 2 Differential input signal pair, channel B. If unused, the pins should be tied to VCM. Do not float. INC_P, INC_M 34,35 I 2 Differential input signal pair, channel C. If unused, the pins should be tied to VCM. Do not float. 28 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 PIN ASSIGNMENTS (1-WIRE INTERFACE) (continued) PINS NAME IND_P, IND_M NO. 37,38 I/O NO. OF PINS I 2 Differential input signal pair, channel D. If unused, the pins should be tied to VCM. Do not float. 1 Connect 2-nF capacitance from pin to ground DESCRIPTION CAP 5 SCLK 44 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). Refer to Table 5 for description. This pin has an internal pull-down resistor. SDATA 43 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). Refer to Table 5 for description. This pin has an internal pull-down resistor. SEN 42 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. Refer to Table 6 for description. This pin has an internal pull-up resistor. 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 6 I 1 PDN 41 I 1 Global power down control pin. CFG1 30 I 1 Parallel input pin. It controls 1-wire or 2-wire interface and DDR or SDR bit clock selection. Refer to Table 8 for description. Tie to ground for 1-wire interface with DDR bit clock. CFG2 29 I 1 Parallel input pin. It controls 12x or 14x serialization and SDR bit clock capture edge. Refer to Table 9 for description. For 12x serialization with DDR bit clock, tie to ground or AVDD. CFG3 28 I 1 RESERVED pin - TIE to ground. CFG4 21 I 1 Parallel input pin. It controls data format and MSB or LSB first modes. Refer to Table 11 for description. VCM 22 I/O 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 62,63 O 2 Channel A differential LVDS data output pair DB_P,DB_M 60,61 O 2 Channel B differential LVDS data output pair DC_P,DC_M 52,53 O 2 Channel C differential LVDS data output pair DD_P,DD_M 50,51 O 2 Channel D differential LVDS data output pair DCLKP,DCLKM 57,58 O 2 Differential bit clock output pair FCLKP,FCLKM 55,56 O 2 Differential frame clock output pair 1-4,45-48 8 These pins are unused in the 1-wire interface. Do not connect NC 20 1 Do Not Connect PAD 0 1 Connect to ground plane using multiple vias. See 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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 29 ADS6424 ADS6423 ADS6422 SLAS532B – 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) ADS6424 (Fsrated = 105 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 91.7 dBc SINAD = 71.2 dBFS SNR = 71.2 dBFS THD = 89.8 dBc −20 −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 50 f − Frequency − MHz 0 10 20 30 40 50 f − Frequency − MHz G001 G002 Figure 6. Figure 7. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 0 SFDR = 80 dBc SINAD = 67.5 dBFS SNR = 67.8 dBFS THD = 79.5 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –88 dBFS SFDR = –88 dBFS −20 −40 Amplitude − dB −40 Amplitude − dB SFDR = 81.1 dBc SINAD = 69.7 dBFS SNR = 70.4 dBFS THD = 79.8 dBc −20 Amplitude − dB −40 Amplitude − dB 0 −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 f − Frequency − MHz G003 Figure 8. 50 G004 Figure 9. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 72 92 90 71 Gain = 0 dB 86 SNR − dBFS SFDR − dBc 88 Gain = 3.5 dB 84 82 70 69 Gain = 3.5 dB 68 80 78 Gain = 0 dB 67 76 74 66 0 50 100 150 200 fIN − Input Frequency − MHz 250 G005 0 50 100 Figure 10. 30 Submit Documentation Feedback 150 fIN − Input Frequency − MHz 200 250 G006 Figure 11. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 72 92 Input adjusted to get −1dBFS input 90 88 2 dB 70 3 dB 84 82 6 dB 80 69 68 67 2 dB 66 78 4 dB 1 dB 0 dB 76 65 74 64 10 30 50 70 90 5 dB 6 dB 20 110 130 150 170 190 210 230 fIN − Input Frequency − MHz 40 60 80 G007 PERFORMANCE vs AVDD PERFORMANCE vs LVDD fIN = 70.1 MHz LVDD = 3.3 V 77 94 73 fIN = 70.1 MHz AVDD = 3.3 V 72 75 80 74 78 73 76 72 SNR 3.1 3.2 3.3 86 70 SFDR 82 3.4 78 3.0 70 3.6 3.5 3.1 3.2 PERFORMANCE vs TEMPERATURE 100 74 82 73 80 72 SNR 71 76 SNR − dBFS SFDR SFDR − dBc 68 3.6 G010 110 70 85 90 80 80 75 SNR (dBFS) 70 70 60 65 SFDR (dBc) 50 30 −40 69 T − Temperature − °C 90 SFDR (dBFS) 60 40 fIN = 70.1 MHz 60 SFDR − dBc, dBFS 84 40 3.5 PERFORMANCE vs INPUT AMPLITUDE 75 20 3.4 Figure 15. 86 0 3.3 LVDD − Supply Voltage − V G009 Figure 14. −20 69 71 AVDD − Supply Voltage − V 78 71 SNR 80 G011 SNR − dBFS 74 90 SNR − dBFS SFDR 82 SFDR − dBc 76 SNR − dBFS SFDR − dBc 98 78 84 74 −40 G008 Figure 13. 88 72 3.0 100 120 140 160 180 200 220 fIN − Input Frequency − MHz Figure 12. 86 1 dB 3 dB SINAD − dBFS 5 dB 86 SFDR − dBc 3.5 dB 0 dB 71 4 dB 55 fIN = 20.1 MHz −30 −20 −10 50 0 Input Amplitude − dBFS Figure 16. G012 Figure 17. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 31 ADS6424 ADS6423 ADS6422 SLAS532B – 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 PERFORMANCE vs CLOCK DUTY CYCLE 82 74 90 74 fIN = 20.1 MHz 73 fIN = 70.1 MHz 80 71 84 70 82 69 80 78 72 76 68 SFDR 78 1.0 1.5 2.0 74 66 3.0 2.5 Input Clock Amplitude − VPP 70 72 69 35 40 45 50 60 65 Input Clock Duty Cycle − % G013 G014 Figure 19. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 2.0 45 1.8 40 1.6 35 RMS (LSB) = 0.407 Occurence − % 1.4 1.2 1.0 AVDD 0.8 0.6 30 25 20 15 10 LVDD 0.4 5 0 0.0 0 20 40 60 80 fS − Sampling Frequency − MSPS 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 100 G033 Output Code Figure 20. CMRR vs FREQUENCY 74 fIN = 70.1 MHz External Reference Mode 72 SNR 82 70 68 SFDR 81 SNR − dBFS 84 66 80 1.30 1.35 1.40 1.45 1.50 1.55 1.60 VVCM − VCM Voltage − V 1.65 64 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 83 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. 85 SFDR − dBc 55 Figure 18. 0.2 32 71 SNR 67 76 0.5 PD − Power Dissipation − W SFDR − dBc SNR 86 73 SFDR 72 SNR − dBFS SFDR − dBc 88 SNR − dBFS 92 250 300 G018 Figure 23. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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) ADS6423 (Fsrated = 80 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 91.2 dBc SINAD = 71.2 dBFS SNR = 71.3 dBFS THD = 88.3 dBc −20 SFDR = 85.8 dBc SINAD = 70.6 dBFS SNR = 70.9 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 G020 Figure 25. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 0 SFDR = 81 dBc SINAD = 68.3 dBFS SNR = 68.4 dBFS THD = 79.5 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –92 dBFS SFDR = –93 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 f − Frequency − MHz 40 0 10 20 30 40 f − Frequency − MHz G021 Figure 26. G022 Figure 27. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 94 74 92 73 90 72 Gain = 3.5 dB 88 SNR − dBFS SFDR − dBc 30 86 84 82 Gain = 0 dB 70 69 Gain = 3.5 dB 68 80 67 78 66 76 65 74 Gain = 0 dB 71 64 0 50 100 150 200 fIN − Input Frequency − MHz 250 G023 0 50 100 150 200 250 fIN − Input Frequency − MHz Figure 28. G024 Figure 29. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 33 ADS6424 ADS6423 ADS6422 SLAS532B – 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 74 94 Input adjusted to get −1dBFS input 92 72 5 dB 88 86 3 dB 84 6 dB 82 2 dB 71 SINAD − dBFS 90 SFDR − dBc 73 4 dB 3.5 dB 3 dB 0 dB 70 69 68 2 dB 67 80 66 1 dB 78 4 dB 5 dB 65 0 dB 76 6 dB 64 10 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 G025 Figure 30. G026 Figure 31. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 94 92 76 fIN = 50.1 MHz LVDD = 3.3 V 92 1 dB 91 75 73 fIN = 50.1 MHz AVDD = 3.3 V 72 88 73 86 72 90 71 89 70 88 69 SFDR SNR 84 87 71 82 3.0 3.1 3.2 3.3 3.4 86 3.0 70 3.6 3.5 AVDD − Supply Voltage − V 68 3.1 3.2 3.4 3.5 67 3.6 G028 Figure 33. PERFORMANCE vs TEMPERATURE 92 PERFORMANCE vs INPUT AMPLITUDE 75 fIN = 50.1 MHz 110 90 100 85 88 73 86 72 SNR 84 71 90 80 SFDR (dBFS) 80 75 70 70 SNR (dBFS) 60 65 SFDR (dBc) 50 60 40 82 −40 70 −20 0 20 40 T − Temperature − °C 60 30 −40 80 G029 55 fIN = 20.1 MHz 50 −30 −20 Input Amplitude − dBFS Figure 34. Submit Documentation Feedback SNR − dBFS SFDR SNR − dBFS 74 SFDR − dBc, dBFS 90 SFDR − dBc 3.3 LVDD − Supply Voltage − V G027 Figure 32. 34 SNR − dBFS 74 SFDR SFDR − dBc 90 SNR − dBFS SFDR − dBc SNR −10 0 G030 Figure 35. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 PERFORMANCE vs CLOCK DUTY CYCLE 75 88 73 SFDR 86 SFDR 72 84 71 SNR 82 70 80 69 78 68 73 80 72 78 76 71 SNR 74 76 0.5 fIN = 50.1 MHz 1.0 1.5 2.0 67 3.0 2.5 70 72 35 40 45 50 G032 Figure 37. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 40 1.8 35 RMS (LSB) = 0.407 1.6 30 1.4 1.2 1.0 AVDD 0.8 0.6 25 20 15 10 0.4 LVDD 5 0.2 0 0.0 0 20 40 60 2036 2037 2038 2039 2040 2041 2042 2043 2044 80 fS − Sampling Frequency − MSPS G051 Output Code Figure 38. CMRR vs FREQUENCY 75 fIN = 50.1 MHz External Reference Mode 73 SNR 92 71 SFDR 69 88 SNR − dBFS 94 67 1.35 1.40 1.45 1.50 1.55 1.60 VVCM − VCM Voltage − V 1.65 65 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 90 G034 Figure 39. 96 SFDR − dBc 69 65 60 Input Clock Duty Cycle − % G031 2.0 86 1.30 55 Figure 36. Occurence − % PD − Power Dissipation − W Input Clock Amplitude − VPP SNR − dBFS 74 fIN = 20.1 MHz SNR − dBFS 90 74 82 SFDR − dBc SFDR − dBc 92 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 50 G035 Figure 40. 100 150 200 250 300 f − Frequency − MHz G018 Figure 41. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 35 ADS6424 ADS6423 ADS6422 SLAS532B – 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) ADS6422 (Fsrated = 65 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 SFDR = 92.5 dBc SINAD = 71.3 dBFS SNR = 71.4 dBFS THD = 90.1 dBc −20 −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 0 10 G038 Figure 43. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –96 dBFS SFDR = –87 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 30 f − Frequency − MHz G039 Figure 44. G040 Figure 45. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 96 74 94 73 92 72 90 88 SNR − dBFS SFDR − dBc 30 f − Frequency − MHz G037 SFDR = 81.5 dBc SINAD = 68.1 dBFS SNR = 68.4 dBFS THD = 80.3 dBc −20 Gain = 3.5 dB 86 84 82 Gain = 0 dB 71 70 Gain = 3.5 dB 69 68 80 Gain = 0 dB 67 78 76 66 0 50 100 150 200 fIN − Input Frequency − MHz 250 G041 0 50 100 Submit Documentation Feedback 150 fIN − Input Frequency − MHz Figure 46. 36 20 Figure 42. 0 Amplitude − dB SFDR = 86.7 dBc SINAD = 71 dBFS SNR = 71.3 dBFS THD = 83.7 dBc −20 Amplitude − dB −40 Amplitude − dB 0 200 250 G042 Figure 47. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 96 74 Input adjusted to get −1dBFS input 94 92 3 dB 4 dB 88 86 84 6 dB 82 3.5 dB 1 dB 72 2 dB 71 SINAD − dBFS 90 SFDR − dBc 73 5 dB 3 dB 70 69 68 67 2 dB 80 66 1 dB 78 4 dB 5 dB 65 0 dB 76 6 dB 64 10 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 G043 Figure 48. G044 Figure 49. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 94 92 0 dB 92 76 fIN = 50.1 MHz LVDD = 3.3 V 91 75 73 fIN = 50.1 MHz AVDD = 3.3 V 72 88 73 86 72 90 71 89 70 SFDR 88 69 87 68 SNR − dBFS 74 SFDR SFDR − dBc 90 SNR − dBFS SFDR − dBc SNR SNR 84 3.1 3.2 3.3 3.4 86 3.0 70 3.6 3.5 AVDD − Supply Voltage − V 3.1 3.2 3.4 PERFORMANCE vs TEMPERATURE 94 110 90 73 88 72 SNR − dBFS 74 SNR 86 71 SFDR − dBc, dBFS 92 90 100 75 SFDR 90 80 85 SFDR (dBFS) 80 75 SNR (dBFS) 70 60 70 65 SFDR (dBc) 50 60 40 55 fIN = 50.1 MHz 30 −40 70 0 20 40 G046 PERFORMANCE vs INPUT AMPLITUDE 76 −20 67 3.6 Figure 51. 96 84 −40 3.5 LVDD − Supply Voltage − V G045 Figure 50. SFDR − dBc 3.3 60 T − Temperature − °C 80 G047 SNR − dBFS 82 3.0 71 fIN = 20.1 MHz −30 −20 −10 50 0 Input Amplitude − dBFS Figure 52. G048 Figure 53. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 37 ADS6424 ADS6423 ADS6422 SLAS532B – 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 96 PERFORMANCE vs CLOCK DUTY CYCLE 83 78 fIN = 50.1 MHz 94 74 fIN = 20.1 MHz 77 81 88 74 86 73 84 SFDR 79 82 72 77 72 SNR 1.0 1.5 75 70 2.5 2.0 Input Clock Amplitude − VPP 70 73 69 35 40 45 50 60 65 Input Clock Duty Cycle − % G049 G050 Figure 55. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 2.0 40 1.8 35 RMS (LSB) = 0.407 1.6 30 Occurence − % 1.4 1.2 1.0 0.8 AVDD 0.6 25 20 15 10 0.4 LVDD 5 0 0.0 0 10 20 30 40 50 fS − Sampling Frequency − MSPS 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 60 G069 Output Code Figure 56. CMRR vs FREQUENCY 74 fIN = 50.1 MHz External Reference Mode 72 SNR 90 70 68 SFDR 88 SNR − dBFS 94 66 1.35 1.40 1.45 1.50 1.55 1.60 VVCM − VCM Voltage − V 1.65 64 1.70 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 G053 Figure 58. Submit Documentation Feedback G052 Figure 57. 96 86 1.30 55 Figure 54. 0.2 SFDR − dBc 71 SNR 71 80 0.5 38 SNR − dBFS 75 SFDR SFDR − dBc 90 PD − Power Dissipation − W 73 76 SNR − dBFS SFDR − dBc 92 250 300 G018 Figure 59. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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) Contour Plots Across Input and Sampling Frequencies 105 fS - Sampling Frequency - MSPS 100 90 84 87 90 69 81 66 84 75 81 80 72 78 69 84 84 70 63 75 87 90 66 72 78 60 84 84 50 69 78 93 40 87 75 84 96 72 66 84 30 10 50 150 100 200 250 300 400 350 450 500 fIN - Input Frequency - MHz 60 70 65 75 90 85 80 95 SFDR - dBc M0049-10 Figure 60. SFDR Contour (no gain) 105 95 100 fS - Sampling Frequency - MSPS 89 90 83 86 83 68 83 89 92 71 74 77 80 74 80 80 95 70 92 83 86 89 71 77 68 95 60 74 77 50 95 40 92 98 95 30 10 86 89 83 80 80 68 80 92 50 100 71 150 200 250 77 300 74 400 350 450 500 fIN - Input Frequency - MHz 65 70 75 80 85 SFDR - dBc 90 95 M0049-11 Figure 61. SFDR Contour (3.5 dB coarse gain) Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 39 ADS6424 ADS6423 ADS6422 SLAS532B – 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) 105 100 69 70 71 64 65 fS - Sampling Frequency - MSPS 66 90 67 68 80 70 70 71 65 69 64 66 60 67 68 50 71 66 68 30 10 50 100 200 63 64 67 150 64 65 69 70 40 250 300 62 400 350 450 500 fIN - Input Frequency - MHz 60 66 64 62 68 70 72 SNR - dBFS M0048-10 Figure 62. SNR Contour (no gain) 105 100 fS - Sampling Frequency - MSPS 68 69 70 65 67 90 66 64 80 68 69 70 65 70 60 67 64 66 50 68 40 70 30 10 50 100 65 69 150 67 200 64 66 250 300 63 63 62 62 61 61 400 350 450 500 fIN - Input Frequency - MHz 60 62 64 68 66 SNR - dBFS 70 M0048-11 Figure 63. SNR Contour (3.5 dB coarse gain) 40 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 APPLICATION INFORMATION THEORY OF OPERATION The ADS6425/ADS6424/ADS6423/ADS6422 (ADS642X) is a family of quad channel, 12-bit pipeline ADC up to 125 MSPS sampling frequency. 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 12-bit word with a latency of 12 clock cycles. The 12-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 12-bit word boundary. ANALOG INPUT The analog input consists of a switched-capacitor based differential sample and hold architecture, shown in Figure 64. 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 (see Figure 65, shown by the transfer function from the analog input pins to the voltage across the sampling capacitors). 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 64. Input Sampling Circuit Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 41 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 1 Magnitude − dB 0 −1 −2 −3 −4 −5 −6 0 100 200 300 400 500 600 fIN − Input Frequency − MHz 700 G073 Figure 65. Analog Input Bandwidth (represented by magnitude of TF_ADC, see Figure 67 ) 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 66 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. 42 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 66. ADC Input Impedance, Zin Using RF-Transformer Based Drive Circuits For optimum performance, the analog inputs must be driven differentially. This improves the common-mode noise immunity and even order harmonic rejection. An example of input drive using RF transformers is shown in Figure 67 and Figure 68. 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. Figure 67 shows a configuration using a single 1:1 turns ratio transformer (for example, WBC1-1) that can be used for low input frequencies up to 100 MHz. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 43 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com TF_ADC 0.1 mF ADS6xxx 5W INP 0.1 mF 25 W 25 W INM 5W 1:1 VCM S0256-01 Figure 67. 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 68 shows an example using two transformers (Coilcraft WBC1-1). An additional termination resistor pair (enclosed within the shaded box) 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 5W 1:1 VCM S0164-04 Figure 68. Two Transformer Drive Circuit 44 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Using Differential Amplifier Drive Circuits Figure 69 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 69). As shown in the figure, RFIL helps to isolate the amplifier output from the switching inputs of the ADC. Together with CFIL, 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 of the ADC input pins 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 1.5 V. In this case, use +4-V and –1-V supplies for the THS4509 to ensure it's output common-mode voltage (1.5 V) 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 RS || RT 0.1 mF 5W 0.1 mF 500 W VCM –VS ADS6xxx 0.1 mF 10 mF 0.1 mF RF S0259-01 Figure 69. 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 ADS642X 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 (refer to Table 13). Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 45 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com INTREF Internal Reference VCM 1 kW INTREF 4 kW EXTREF REFM REFP ADS6xxx S0165-04 Figure 70. 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 ADS642X 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 listed in Table 21. 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). 46 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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 (refer to Table 18) and (refer to Table 17). Note that the default gain after reset is 0 dB. Table 21. 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 ADS642X 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 71. This allows using transformer-coupled drive circuits for sine wave clock or ac-coupling for LVPECL, LVDS clock sources (see Figure 72 and Figure 74). VCM VCM 5 kW 5 kW CLKP CLKM ADS6xxx S0166-04 Figure 71. Internal Clock Buffer Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 47 ADS6424 ADS6423 ADS6422 SLAS532B – 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 72. Differential Clock Driving Circuit Figure 73 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 73. 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 74. 0.1 mF CMOS Clock Input CLKP 0.1 mF CLKM ADS6xxx S0168-07 Figure 74. Single-Ended Clock Driving Circuit 48 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 1 VPP 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 (refer to Table 14) and increases monotonically from Gain 0 to Gain 5 settings. Table 22 lists the minimum clock amplitude supported for each gain setting. Table 22. Minimum Clock Amplitude Across Gains CLOCK BUFFER GAIN MINIMUM CLOCK AMPLITUDE SUPPORTED, mVPP 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 ADS642X 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 (refer to Table 13). 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 (refer to Table 13). 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 Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 49 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Table 23. Power Down Modes Summary POWER DOWN MODE AVDD POWER (mW) LVDD POWER (mW) WAKE UP TIME In power-up 1360 297 – Global power down 100 μs 12 (1) 1115 2 Channels in standby 825 (1) 3 Channels in standby 532 (1) 4 Channels in standby 245 (1) Input clock stop (1) 65 1 Channel in standby 200 297 (1) 200 Clocks 297 (1) 200 Clocks 297 (1) 200 Clocks 297 (1) 200 Clocks 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. 50 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 DIGITAL OUTPUT INTERFACE The ADS642X 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, 12× and 14× serialization with DDR bit clock • 2-Wire, 1× frame clock, 12× 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 24. 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 DDR Bit clock 12× Serialization 65 390 65 780 14× Serialization 65 455 65 910 2-Wire DDR Bit clock 12× Serialization 125 375 125 750 14× Serialization 125 437.5 62.5 875 2-Wire SDR Bit clock 12× Serialization 65 390 65 390 14× Serialization 65 455 65 455 1-Wire Each interface option is described in detail below. 1-WIRE INTERFACE - 12× AND 14× 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 12 × sample frequency (12× serialization) and 14 × sample frequency (14× serialization). Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 51 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com Input Clock, CLK Freq = Fs 14-Bit Serialization (1) 12-Bit Serialization Frame Clock, FCLK Freq = 1 ´ Fs Bit Clock, DCLK Freq = 6 ´ Fs Output Data DA, DB, DC, DD Data Rate = 12 ´ Fs D11 (D0) D10 (D1) D9 (D2) D8 (D3) D7 (D4) D6 (D5) D5 (D6) D7 (D6) D6 (D7) D3 (D8) D4 (D7) D2 (D9) D1 (D10) D0 (D11) D11 (D0) D0 (0) 0 (D0) D10 (D1) Bit Clock, DCLK Freq = 7 ´ Fs Output Data DA, DB, DC, DD Data Rate = 14 ´ Fs 0 (D0) 0 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D5 (D8) D4 (D9) D3 D2 (D10) (D11) D1 (0) Sample N 0 (D1) Sample N + 1 Data Bit in MSB First Mode D13 (D2) Data Bit in LSB First Mode (1) In 14-Bit serialization, two zero bits are padded to the 12-bit ADC data on the MSB side. T0225-01 Figure 75. 1-Wire Interface 2-WIRE INTERFACE - 12× SERIALIZATION WITH DDR/SDR BIT CLOCK The 2-wire interface is recommended for sampling frequencies above 65 MSPS. The device outputs the data of each ADC serially on two LVDS pairs (2-wire). The data rate is 6 × sample frequency since 6 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. 52 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Input Clock, CLK Freq = Fs Frame Clock, FCLK Freq = 1 ´ Fs Bit Clock – SDR, DCLK Freq = 6 ´ Fs In Byte-Wise Mode Bit Clock – DDR, DCLK Freq = 3 ´ Fs Output Data DA0, DB0, DC0, DD0 D5 (D0) D4 (D1) D3 (D2) D2 (D3) D1 (D4) D0 (D5) D5 (D0) D4 (D1) D3 (D2) D2 (D3) D1 (D4) D0 (D5) Output Data DA1, DB1, DC1, DD1 D11 (D6) D10 (D7) D9 (D8) D8 (D9) D7 D6 D11 (D6) D10 (D7) D9 (D8) D8 (D9) D7 D6 (D10) (D11) (D10) (D11) D10 (D0) D8 (D2) D6 (D4) D4 (D6) D2 (D8) (D10) In Word-Wise Mode In Bit-Wise Mode Data Rate = 6 ´ Fs Output Data DA0, DB0, DC0, DD0 D10 (D0) D8 (D2) D6 (D4) D4 (D6) D2 (D8) (D10) Output Data DA1, DB1, DC1, DD1 D11 (D1) D9 (D3) D7 (D5) D5 (D7) D3 (D9) (D11) D11 (D1) D9 (D3) D7 (D5) D5 (D7) D3 (D9) (D11) Output Data DA0, DB0, DC0, DD0 D11 (D0) D10 (D1) D9 (D2) D8 (D3) D7 (D4) D6 (D5) D5 (D6) D4 (D7) D3 (D8) D2 (D9) D1 D0 (D10) (D11) Output Data DA1, DB1, DC1, DD1 D11 (D0) D10 (D1) D9 (D2) D8 (D3) D7 (D4) D6 (D5) D5 (D6) D4 (D7) D3 (D8) D2 (D9) (D10) (D11) D0 D1 Data Bit in MSB First Mode D1 D0 D1 D0 White Cells – Sample N D5 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0226-01 Figure 76. 2-Wire Interface 12× Serialization Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 53 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 2-WIRE INTERFACE - 14× SERIALIZATION In 14× serialization, two zero bits are padded to the 14-bit ADC data on the MSB side and the combined 14-bit 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. Using the 14× serialization makes it possible to upgrade to a 14-bit ADC in the 64xx family 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: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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 0 (D7) 0 (D8) D11 (D9) D10 D9 D8 (0) D7 (0) 0 (D7) 0 (D8) D11 (D9) D10 D9 (D10) (D11) (D10) (D11) D8 (0) D7 (0) 0 (D7) 0 (D8) D2 D0 (0) 0 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 (D10) D0 (0) 0 (D0) D10 (D2) (D11) D1 (0) 0 (D1) D11 (D3) D1 (0) D0 (0) 0 (D0) 0 (D1) D1 (0) D0 (0) 0 (D0) 0 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 0 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) Output Data DA1, DB1, DC1, DD1 0 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) D1 (0) 0 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 0 (D0) 0 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) Output Data DA1, DB1, DC1, DD1 0 (D0) 0 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) D3 Data Bit in MSB First Mode D3 D2 D3 White Cells – Sample N D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0227-01 Figure 77. 2-Wire Interface 14× Serialization - SDR Bit Clock Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 55 ADS6424 ADS6423 ADS6422 SLAS532B – 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 0 (D7) 0 (D8) D11 (D9) D10 D9 D8 (0) D7 (0) 0 (D7) 0 (D8) D11 (D9) D10 D9 (D10) (D11) (D10) (D11) D8 (0) D7 (0) 0 (D7) 0 (D8) D2 D0 (0) 0 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 (D10) D0 (0) 0 (D0) D10 (D2) (D11) D1 (0) 0 (D1) D11 (D3) D1 (0) D0 (0) 0 (D0) 0 (D1) D1 (0) D0 (0) 0 (D0) 0 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 0 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) Output Data DA1, DB1, DC1, DD1 0 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) D1 (0) 0 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 0 (D0) 0 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) Output Data DA1, DB1, DC1, DD1 0 (D0) 0 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) D3 D3 D2 D3 White Cells – Sample N Data Bit in MSB First Mode D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0228-01 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 78. 2-Wire interface 14× Serialization - DDR Bit Clock 56 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – 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, DB0, DC0 and DD0 carry the 6 LSB bits D5-D0 and wires DA1, DB1, DC1 and DD1 carry the 6 MSB bits. Bit-wise: Each 14-bit sample is split across the 2 wires. Wires DA0, DB0, DC0 and DD0 carry the 6 even bits (D0,D2,D4..) and wires DA1, DB1, DC1 and DD1 carry the 6 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, DB0, DC0 and DD0, while sample N+1 is sent over wires DA1, DB1, DC1 and DD1. 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 (D11,D10,...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 0xFFF in offset binary output format, and 0x7FF in 2s complement output format. For a negative input overdrive, the output code is 0x000 in offset binary output format and 0x800 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 , refer to Table 19). 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 , refer to Table 20). 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 79 and Figure 80 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 , refer to Table 19). Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 57 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com C001 Figure 79. LVDS Data Eye Diagram with 5-pF Load Capacitance (No Internal Termination) C002 Figure 80. LVDS Data Eye Diagram with 10-pF Load Capacitance (100 Ω Internal Termination) 58 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 CAPTURE TEST PATTERNS ADS642X 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 6 '1's followed by 6 '0's (from MSB to LSB). This information can be used by the receiver logic to shift the deserialized data until it matches the SYNC pattern. In addition to DESKEW and SYNC, the ADS642X 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 25. Test Patterns PATTERN DESCRIPTION All zeros Outputs logic low. All ones Outputs logic high. Toggle Outputs toggle pattern – alternates between 101010101010 and 010101010101 every clock cycle. Custom Outputs a 12-bit custom pattern. The 12-bit custom pattern can be specified into two serial interface registers. In the 2wire 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 = 101010101010 or = 010101010101 every clock cycle. Table 26. SYNC Pattern INTERFACE OPTION SERIALIZATION 1-Wire 2-Wire SYNC PATTERN ON EACH WIRE 12 X MSB-111111000000-LSB 14 X MSB-11111110000000-LSB 12 X MSB-111000-LSB 14 X MSB-1111000-LSB Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 59 ADS6424 ADS6423 ADS6422 SLAS532B – 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 following tables. Table 28 to Table 31: 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 27. Clock Propagation Delay and Serializer Latency for different interface options INTERFACE SERIALIZATION CLOCK PROPAGATION DELAY, tpd_clk 12X tpd_clk = 0.5xTs + tdelay 14X tpd_clk = 0.428xTs + tdelay 1-Wire with DDR bit clock 2-Wire with DDR bit clock 2-Wire with SDR bit clock 2-Wire with DDR bit clock 12X (1) 0 tpd_clk = tdelay 1 tpd_clk = 0.5xTs + tdelay 0 2 (when tpd_clk ≥ Ts) tpd_clk = 0.857xTs + tdelay 14X 2-Wire with SDR bit clock (1) SERIALIZER LATENCY clock cycles 1 (when tpd_clk < Ts) tpd_clk = 0.428xTs + tdelay 0 Note that the total latency = ADC latency + serializer latency. The ADC latency is 12 clocks. Table 28. Timings for 1-Wire Interface SERIALIZATION 12× 14× DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 65 0.4 0.6 0.5 0.7 40 0.8 1.0 0.9 1.1 20 1.6 2.0 1.8 2.2 10 3.5 4.0 3.5 4.2 MAX 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 tdelay ns MAX MIN TYP MAX Fs ≥ 40 MSPS 3 4 5 Fs < 40 MSPS 3 4.5 6 Fs ≥ 40 MSPS 3 4 5 Fs < 40 MSPS 3 4.5 6 Table 29. Timings for 2-Wire Interface, DDR Bit Clock SERIALIZATION 12× 14× 60 DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 105 0.55 0.75 0.6 0.8 92 0.65 0.85 0.7 0.9 80 0.8 1.0 0.8 1.05 65 0.9 1.2 1.0 1.3 40 1.7 2.0 1.1 2.1 105 0.45 0.65 0.5 0.7 92 0.55 0.75 0.6 0.8 80 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 Submit Documentation Feedback MAX tdelay ns MAX 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 5 Fs < 45 MSPS 3 4.5 6 Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 Table 30. 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 1.0 1.2 1.1 1.3 40 1.8 2.0 1.9 2.1 20 3.9 4.1 3.8 4.1 10 8.2 8.4 7.8 8.2 65 0.8 1.0 1.0 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 12× 14× 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 31. 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 350 TYP MAX 75 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 ADS644X 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 3.3-V 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 It is necessary to solder the exposed pad at the bottom of the package to a ground plane for best thermal performance. For detailed information, see application notes QFN Layout Guidelines (SLOA122A) and QFN/SON PCB Attachment (SLUA271A). Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 61 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com 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. This delay will be different across channels. The maximum variation is specified as aperture delay variation (channel-channel). 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. The gain error does not include the error caused by the internal reference deviation from ideal value. This is specifed separately as internal reference error. The maximum variation of the gain error across devices and across channels within a device is specified separately. 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) 62 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 ADS6424 ADS6423 ADS6422 www.ti.com SLAS532B – MAY 2007 – REVISED DECEMBER 2013 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). 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 neighboring 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. Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 Submit Documentation Feedback 63 ADS6424 ADS6423 ADS6422 SLAS532B – MAY 2007 – REVISED DECEMBER 2013 www.ti.com REVISION HISTORY Changes from Revision A (June 2007) to Revision B Page • Added Frame setup time and Frame hold time to the TIMING SPECIFICATIONS table .................................................. 10 • Changed Figure 2 ............................................................................................................................................................... 13 • 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)" .................................................................................................................................................... 14 • Changed Figure 3 ............................................................................................................................................................... 15 • Changed Table 8 ................................................................................................................................................................ 16 • Changed Table 9 ................................................................................................................................................................ 16 • Changed Table 11 .............................................................................................................................................................. 17 • Added Note 3 to Table 12 ................................................................................................................................................... 20 • Added note to the DESCRIPTION OF SERIAL REGISTERS - “After a hardware or software reset, all register bits are cleared to ‘0’" ................................................................................................................................................................ 21 • Added 32K point FFT to TYPICAL CHARACTERISTICS test conditions .......................................................................... 30 • Added Gain 5 setting to CLOCK BUFFER GAIN section ................................................................................................... 49 • Added Note A to Figure 78 ................................................................................................................................................. 56 64 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: ADS6424 ADS6423 ADS6422 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) ADS6422IRGCR ACTIVE VQFN RGC 64 2000 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6422 ADS6422IRGCT ACTIVE VQFN RGC 64 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6422 ADS6423IRGCT ACTIVE VQFN RGC 64 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6423 ADS6424IRGCT ACTIVE VQFN RGC 64 250 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 AZ6424 (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