ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 QUAD CHANNEL, 14-BIT, 125/105/80/65 MSPS ADC WITH SERIAL LVDS OUTPUTS FEATURES • • • • • • • • • Maximum Sample Rate: 125 MSPS 14-Bit Resolution with No Missing Codes Simultaneous Sample and Hold 3.5dB Coarse Gain and up to 6dB Programmable Fine Gain for SFDR/SNR Trade-Off 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 12-Bit Family (ADS642X SLAS532) Feature Compatible Dual Channel Family (ADS624X - SLAS542, ADS644X - SLAS543) APPLICATIONS • • • • 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 ADS6424 ADS6423 ADS6422 Table 2. Performance Summary SFDR, dBc SINAD, dBFS ADS6445 ADS6444 ADS6443 ADS6442 Fin = 10MHz (0 dB gain) 87 91 92 93 Fin = 170MHz (3.5 dB gain) 79 83 84 84 Fin = 10MHz (0 dB gain) 73.4 73.4 74.2 74.3 Fin = 170MHz (3.5 dB gain) 68.3 69.3 69.4 70 420 340 300 265 Power, per channel, mW DESCRIPTION The ADS6445/ADS6444/ADS6443/ADS6442 (ADS644X) is a family of high performance 14-bit 125/105/80/65 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 ADS644X also includes the traditional 1-wire interface that can be used at lower sampling frequencies. An internal phase lock loop (PLL) multiplies the incoming ADC sampling clock to derive the bit clock. The bit clock is used to serialize the 14-bit data from each channel. In addition to the serial data streams, the frame and bit clocks are also transmitted as LVDS outputs. The LVDS output buffers have features such as programmable LVDS currents, current doubling modes and internal termination options. These can be used to widen eye-openings and improve signal integrity, easing capture by the receiver. The ADC channel outputs can be transmitted either as MSB or LSB first and 2s complement or straight binary. 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, Texas Instruments Incorporated ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. DESCRIPTION (CONTINUED) LVDD LGND CAP AVDD AGND The ADS644X has internal references, but can also support an external reference mode. The device is specified over the industrial temperature range (–40°C to 85°C). CLKP CLKM BIT Clock DCLKP DCLKM FRAME Clock FCLKP FCLKM PLL SHA 14-Bit ADC Digital Encoder and Serializer SHA 14-Bit ADC Digital Encoder and Serializer 14-Bit ADC Digital Encoder and Serializer 14-Bit ADC Digital Encoder and Serializer INA_P INA_M INB_P INB_M INC_P SHA INC_M IND_P SHA 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 ADS644x B0199-03 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ADS6445 QFN-64 (2) RGC –40°C to 85°C AZ6445 ADS6444 QFN-64 (2) RGC –40°C to 85°C AZ6444 ADS6443 QFN-64 (2) RGC –40°C to 85°C AZ6443 ADS6442 (1) (2) QFN-64 (2) RGC –40°C to 85°C AZ6442 (1) ORDERING NUMBER TRANSPORT MEDIA, QUANTITY ADS6445IRGCT 250, Tape/reel ADS6445IRGCR 2000, Tape/reel ADS6444IRGCT 250, Tape/reel ADS6444IRGCR 2000, Tape/reel ADS6443IRGCT 250, Tape/reel ADS6443IRGCR 2000, Tape/reel ADS6442IRGCT 250, Tape/reel ADS6442IRGCR 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 220 °C Lead temperature 1,6 mm (1/16") from the case for 10 seconds (1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Submit Documentation Feedback 3 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT SUPPLIES AVDD Analog supply voltage 3.0 3.3 3.6 V LVDD LVDS Buffer supply voltage 3.0 3.3 3.6 V 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, Fsrated ADS6445 5 125 ADS6444 5 105 ADS6443 5 80 ADS6442 5 65 Sine wave, ac-coupled Input clock amplitude differential (VCLKP– VCLKM) 0.4 Vpp ± 0.35 LVDS, ac-coupled LVCMOS, ac-coupled Input Clock duty cycle 1.5 ± 0.8 LVPECL, ac-coupled MSPS 3.3 35% 50% 65% DIGITAL OUTPUTS 4 Without internal termination CLOAD Maximum external load capacitance from each output pin to DGND RLOAD Differential load resistance (external) between the LVDS output pairs TA Operating free-air temperature 5 With internal termination Ω 100 –40 Submit Documentation Feedback pF 10 85 °C ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER MIN RESOLUTION TYP MAX UNIT 14 Bits 2.0 VPP ANALOG INPUT Differential input voltage range Differential input capacitance 7 Analog input bandwidth Analog input common mode current (per input pin of each ADC) pF 500 ADS6445 155 ADS6444 130 ADS6443 100 ADS6442 81 MHz µA REFERENCE VOLTAGES VREFB Internal reference bottom voltage 1.0 VREFT Internal reference top voltage 2.0 ∆VREF Internal reference error (VREFT–VREFB) VCM Common mode output voltage 1.5 V VCM output current capability ±4 mA -15 ±2 V V 15 mV DC ACCURACY No missing codes EO Assured Offset error, across devices and across channels within a device –15 Offset error temperature coefficient, across devices and across channels within a device ±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, (∆VREF /2.0) % -0.75 Reference gain error temperature coefficient EGCHAN 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 DNL Differential nonlinearity, Fin = 50 MHz INL Integral nonlinearity, Fin = 50 MHz PSRR DC power supply rejection ratio 0.1 0.75 ±0.3 1 0.005 % FS ∆%/°C ADS6445 and ADS6444 –0.9 ±0.6 2.0 ADS6443 and ADS6442 –0.9 ±0.5 1.8 ADS6445 and ADS6444 -5 ±3 5 ADS6443 and ADS6442 4.5 ±2 4.5 0.5 % FS ∆%/°C 0.0125 LSB LSB mV/V POWER SUPPLY ICC Total supply current IAVDD ILVDD (1) Analog supply current LVDS supply current ADS6445 502 ADS6444 410 ADS6443 360 ADS6442 320 ADS6445 410 ADS6444 322 ADS6443 280 ADS6442 245 ADS6445 92 ADS6444 88 ADS6443 80 ADS6442 75 mA mA mA This is specified by design anad characterization; it is not tested in production. Submit Documentation Feedback 5 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN TYP MAX UNIT POWER SUPPLY (Continued) Total power ADS6445 1.65 1.8 ADS6444 1.35 1.5 ADS6443 1.18 1.3 ADS6442 1.05 1.2 77 150 Power down (with input clock stopped) W mW DYNAMIC AC CHARACTERISTICS ADS6445 73.7 ADS6444 73.8 Fin = 10 MHz ADS6443 74.4 ADS6442 74.5 ADS6445 68.5 ADS6444 73.2 Fin = 50 MHz ADS6443 70 ADS6442 70.5 ADS6445 69 Fin = 70 MHz ADS6443 73 73.4 73.6 ADS6445 72.1 72.2 Fin = 100 MHz ADS6443 72.7 ADS6442 72.8 ADS6445 69.9 ADS6444 0 dB gain ADS6443 ADS6442 ADS6444 70.5 69.4 3.5 dB Coarse gain ADS6443 70.2 70.7 Fin = 170 MHz ADS6445 69.7 69.7 ADS6442 70.2 ADS6445 68.7 ADS6444 0 dB gain ADS6443 ADS6442 Fin = 230 MHz 68.8 68.1 69.2 ADS6445 68.1 ADS6444 and ADS6443 3.5 dB Coarse gain ADS6442 6 74 ADS6442 ADS6444 Signal to noise ratio 73.8 72.7 ADS6444 SNR 73.1 68.2 68.9 Submit Documentation Feedback dBFS ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN ADS6445 and ADS6444 ADS6443 74.2 74.3 ADS6445 ADS6443 68 69.5 73.5 70 73.7 ADS6445 ADS6443 Fin = 70 MHz 73 73.2 71.8 72 Fin = 100 MHz 72.2 ADS6442 72 ADS6445 67.9 ADS6444 0 dB gain ADS6443 ADS6442 ADS6445 69.9 69.3 69.4 ADS6442 70 ADS6445 67.8 ADS6444 0 dB gain ADS6443 ADS6442 ADS6445 ADS6444 ADS6443 67.7 67.6 68.3 Fin = 230 MHz 67.9 3.5 dB Coarse gain ADS6442 Output noise 69.8 68.3 3.5 dB Coarse gain ADS6443 dBFS 70.3 Fin = 170 MHz ADS6444 RMS 72 ADS6445 ADS6443 Signal to noise and distortion ratio 71.2 68.5 ADS6442 ADS6444 SINAD 72.3 71.7 Fin = 50 MHz ADS6442 ADS6444 UNIT 73.4 Fin = 10 MHz ADS6442 ADS6444 TYP MAX 67.6 68.1 68.4 Inputs tied to common-mode Submit Documentation Feedback 1.05 LSB 7 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN ADS6445 91 Fin = 10 MHz ADS6443 92 ADS6442 93 ADS6445 73 ADS6444 ADS6442 77 87 79 88 ADS6445 78 ADS6444 Fin = 70 MHz 74 81 ADS6443 and ADS6442 86 ADS6445 86 ADS6444 88 Fin = 100 MHz ADS6443 84 ADS6442 82 ADS6445 76 ADS6444 0 dB gain ADS6443 ADS6442 Fin = 170 MHz 79 80 81 ADS6445 79 ADS6444 3.5 dB Coarse gain 83 ADS6443 and ADS6442 84 ADS6445 and ADS6444 77 ADS6443 0 dB gain ADS6442 Fin = 230 MHz ADS6445 and ADS6444 ADS6443 and ADS6442 8 81 80 Fin = 50 MHz ADS6443 SFDR UNIT 87 ADS6444 Spurious free dynamic range TYP MAX 78 79 3.5 dB Coarse gain Submit Documentation Feedback 80 82 dBc ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN ADS6445 94 Fin = 10 MHz ADS6443 96 ADS6442 97 ADS6445 73 ADS6444 87 88 Fin = 50 MHz ADS6443 ADS6442 77 90 79 92 ADS6445 87 ADS6444 74 Fin = 70 MHz ADS6443 88 90 ADS6442 92 ADS6445 89 ADS6444 Second harmonic Fin = 100 MHz 90 ADS6443 and ADS6442 87 ADS6445 83 ADS6444 0 dB gain ADS6443 and ADS6442 ADS6445 84 85 3.5 dB Coarse gain 86 ADS6443 and ADS6442 88 ADS6445 80 ADS6444 0 dB gain ADS6443 ADS6445 ADS6444 ADS6443 dBc 86 Fin = 170 MHz ADS6444 ADS6442 UNIT 93 ADS6444 HD2 TYP MAX 81 82 83 Fin = 230 MHz 82 3.5 dB Coarse gain ADS6442 83 84 85 Submit Documentation Feedback 9 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN ADS6445 91 Fin = 10 MHz ADS6443 92 ADS6442 93 ADS6445 73 ADS6444 ADS6442 77 87.5 79 88 ADS6445 78 ADS6444 Fin = 70 MHz 74 86 ADS6445 86 88 Fin = 100 MHz ADS6443 84 ADS6442 82 ADS6445 76 ADS6444 0 dB gain ADS6443 ADS6442 Fin = 170 MHz 79 80 79 ADS6444 3.5 dB Coarse gain 83 ADS6443 and ADS6442 84 ADS6445 and ADS6444 77 ADS6443 0 dB gain ADS6442 Fin = 230 MHz ADS6445 and ADS6444 ADS6445 and ADS6444 ADS6443 78 79 3.5 dB Coarse gain ADS6443 and ADS6442 80 82 91 Fin = 10 MHz ADS6442 94 95 ADS6445 and ADS6444 ADS6443 87 Fin = 50 MHz 92 ADS6442 93 ADS6445 90 ADS6444 Fin = 100 MHz ADS6443 and ADS6442 ADS6445 and ADS6444 ADS6443 and ADS6442 All dBc 81 ADS6445 10 81 ADS6443 and ADS6442 ADS6444 Worst harmonic (other than HD2, HD3) 81 80 Fin = 50 MHz ADS6443 Third harmonic UNIT 87 ADS6444 HD3 TYP MAX 91 92 Fin = 170 MHz Fin = 230 MHz Submit Documentation Feedback 88 90 87 dBc ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 = 3.3V, maximum rated sampling frequency, 50% clock duty cycle, –1dBFS differential analog input, internal reference mode (unless otherwise noted). PARAMETER TEST CONDITIONS MIN ADS6445 86 ADS6444 89.5 ADS6443 Fin = 10 MHz 91 ADS6445 ADS6444 ADS6443 71 Fin = 50 MHz ADS6442 Total harmonic distortion ADS6443 75 85.5 77 85.6 84.5 Fin = 100 MHz 72 83 80.5 ADS6445 73.5 ADS6443 78.5 79.5 ADS6445 74 ADS6443 75 Fin = 230 MHz 76 ADS6442 77 ADS6445 ADS6443 Fin = 50 MHz ADS6442 ADS6444 Fin = 70 MHz ADS6445 ADS6444 ADS6443 IMD 2-tone intermodulation distortion 11.9 11.4 12 11.3 11.7 F1= 46.09 MHz, F2 = 50.09 MHz 90 96 86 F1= 185.09 MHz, F2 = 190.09 MHz 93 96 ADS6445 90 Near channel Cross-talk signal frequency = 10 MHz 92 94 ADS6442 100 ADS6445 103 ADS6444 ADS6443 Far channel Cross-talk signal frequency = 10 MHz ADS6442 dBFS 88 ADS6442 ADS6443 Bits 88 ADS6445 ADS6444 AC PSRR 11.7 11.1 100 ADS6443 Cross-talk 11.0 ADS6442 ADS6444 dBc 77 Fin = 170 MHz ADS6442 ADS6444 Effective number of bits 86 ADS6442 ADS6444 ENOB 80 78.5 ADS6445 ADS6444 UNIT 90 ADS6442 THD TYP MAX dBc 105 106 108 Input overload recovery All Recovery to within 1% (of final value) for 6 dB overload with sine wave input Power Supply Rejection Ratio All < 100 MHz signal, 100 mV pp on AVDD supply Submit Documentation Feedback 1 Clock cycles 35 dBc 11 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 DIGITAL CHARACTERISTICS The DC specifications refer to the condition where the digital outputs are not switching, but are permanently at a valid logic level 0 or 1 AVDD = LVDD = 3.3V, IO = 3.5mA, RLOAD = 100Ω (1). All LVDS specifications are characterized, but not tested at production. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DIGITAL INPUTS High-level input voltage 2.4 V Low-level input voltage 0.8 V High-level input current 10 µA Low-level input current 10 µA 4 pF High-level output voltage 1375 mV Low-level output voltage 1025 Input capacitance DIGITAL OUTPUTS Output differential voltage |VOD| 250 Output offset voltage VOS Common-mode voltage of OUTP and OUTM Output capacitance Output capacitance inside the device, from either output to ground (1) 12 350 mV 450 1200 mV 2 pF IO refers to the LVDS buffer current setting, RLOAD is the external differential load resistance between the LVDS output pair. Submit Documentation Feedback mV ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 TIMING SPECIFICATIONS (1) Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3 V, maximum rated sampling frequency, sine wave input clock, 1.5 VPP clock amplitude, CL = 5 pF (2), IO = 3.5 mA, RL = 100 Ω (3), no internal termination, unless otherwise noted. PARAMETER tJ TEST CONDITIONS Aperture jitter All MIN Uncertainty in the sampling instant TYP MAX 250 UNIT fs rms INTERFACE: 2-wire, DDR bit clock, 14x serialization Data setup time (4) (5) (6) tsu 0.35 0.55 ADS6444 0.45 0.65 0.65 0.85 ADS6443 From data cross-over to bit clock cross-over ADS6442 0.8 1.1 ADS6445 0.35 0.58 0.5 0.7 0.7 0.9 0.8 1.1 3.4 4.4 ADS6444 Data hold time (4) (5) (6) th ADS6445 ADS6443 From bit clock cross-over to data cross-over ADS6442 tpd_clk Clock propagation delay (6) Bit clock cycle-cycle jitter All (5) Frame clock cycle-cycle jitter (5) Input clock rising edge cross-over to frame clock rising edge cross-over ns ns 5.4 ns All 350 ps pp All 75 ps pp Below specifications apply for 5 MSPS ≤ Fs ≤ 125 MSPS and all interface options. tA Aperture delay All Delay from input clock rising edge to the actual sampling instant Aperture delay variation All Channel-channel within same device ADC Latency (7) Wake up time All All 1 2 3 –250 ±80 250 Time for a sample to propagate to ADC outputs, see Figure 1 ns ps Clock cycles 12 µs Time to valid data after coming out of global power down 100 Time to valid data after input clock is re-started 100 µs 200 Clock cycles Time to valid data after coming out of channel standby tRISE Data rise time All From –100 mV to +100 mV 50 100 200 ps tFALL Data fall time All From +100 mV to –100 mV 50 100 200 ps tRISE Bit clock and frame clock rise time All From –100mV to +100mV 50 100 200 ps tFALL Bit clock and frame clock fall time All From +100mV to –100mV 50 100 200 ps LVDS Bit clock duty cycle All 45% 50% 55% LVDS Frame clock duty cycle All 47% 50% 53% (1) (2) (3) (4) (5) (6) (7) 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 shown in Table 27. Submit Documentation Feedback 13 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Sample N+13 Sample N+12 Sample N+11 Sample N Input Signal tA Input Clock CLKM CLKP tPD_CLK Latency 12 Clocks Bit Clock Output Data DCLKP DCLKM DOP D13 D12 D11 D10 D6 D5 D4 D3 D2 D1 D0 D13 D12 D11 D10 Sample N–1 Frame Clock D6 D5 D4 D3 D2 D1 D0 DOM Sample N FCLKM FCLKP T0105-04 Figure 1. Latency DCLKP Bit Clock DCLKM tsu th tsu Output Data DOP, DOM th Dn+1 Dn T0106-03 Figure 2. LVDS Timings 14 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 DEVICE PROGRAMMING MODES ADS644X 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 as illustrated in Figure 3. Table 3 has a description of the modes controlled by the parallel pins. Table 3. Parallel Pin Definition PIN SEN 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 14x/16x Serialization and SDR bit clock capture edge CFG3 Reserved function. Tie CFG3 to Ground. CFG4 MSB/LSB First and data format. USING SERIAL INTERFACE PROGRAMMING ONLY In this mode, SEN, SDATA, and SCLK function as serial interface pins and are used to access the internal registers of ADC. The registers must first be reset to their default values either by applying a pulse on RESET pin or by a high setting on the <RST> 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 <OVRD> - 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 <RST> 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. Submit Documentation Feedback 15 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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). Table 4. Priority Between Parallel Pins and Serial Registers PIN FUNCTIONS SUPPORTED PRIORITY As described in Table 8 to Table 11 Register bits can control the modes only if the register bit <OVRD> is high. If <OVRD> bit is low, then the control voltage on these parallel pins determines the function. PDN Global Power Down Register bit <PDN GLOBAL> controls global power down only if PDN pin is low. If PDN is high, device is in global power down. SEN Serial Interface Enable CFG1 to CFG4 Coarse gain is controlled by register bit <COARSE GAIN>only if the <OVRD> bit is high. Else, device has 0 dB coarse gain. Internal/External Reference setting is determined by register bit <REF>. SCLK, SDATA Serial Interface Clock and Serial Interface Data pins Register bits <PATTERNS> control the sync and deskew output patterns. Power down is determined by bit <PDN GLOBAL> AVDD (5/8) AVDD 3R (5/8) AVDD GND 2R AVDD (3/8) AVDD (3/8) AVDD 3R To Parallel Pin GND Figure 3. Simple Scheme to Configure Parallel Pins 16 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 DESCRIPTION OF PARALLEL PINS Table 5. SCLK, SDATA Control Pins SCLK SDATA LOW LOW NORMAL conversion. DESCRIPTION LOW HIGH SYNC – ADC outputs sync pattern on all channels. This pattern can be used by the receiver to align the deserialized data to the frame boundary. See Capture Test Patterns for details. HIGH LOW POWER DOWN – Global power down, all channels of the ADC are powered down, including internal references, PLL and output buffers. HIGH HIGH DESKEW – ADC outputs deskew pattern on all channels. This pattern can be used by the receiver to ensure deserializer uses the right clock edge. See Capture Test Patterns for details. Table 6. SEN Control Pin SEN 0 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 0 DESCRIPTION DDR Bit clock and 1-wire interface (3/8)LVDD Not used (5/8)LVDD SDR Bit clock and 2-wire interface LVDD DDR Bit clock and 2-wire interface Table 9. CFG2 Control Pin CFG2 DESCRIPTION 0 14x Serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (3/8)LVDD 16x Serialization and capture at falling edge of bit clock (only in 2-wire SDR bit clock mode) (5/8)LVDD 16x Serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) LVDD 14x Serialization and capture at rising edge of bit clock (only in 2-wire SDR bit clock mode) Table 10. CFG3 Control Pin CFG3 RESERVED - TIE TO GROUND Table 11. CFG4 Control Pin CFG4 0 DESCRIPTION MSB First and 2s complement (3/8)LVDD MSB First and offset binary (5/8)LVDD LSB First and offset binary LVDD LSB First and 2s complement Submit Documentation Feedback 17 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 non-50% duty cycle SCLK. The first 5-bits of the 16-bit word are the address of the register while the next 11 bits are the register data. Register Reset After power-up, the internal registers must be reset to their default values. This can be done in one of two ways: 1. Either by applying a high-going pulse on RESET (of width greater than 10ns) OR 2. By applying software reset. Using the serial interface, set the <RST> bit in register 0x00 to high– this resets the registers to their default values and then self-resets the <RST> bit to LOW. When RESET pin is not used, it must be tied to LOW. Register Address SDATA A4 A3 A2 A1 Register Data A0 D10 D9 D8 D7 D6 t(SCLK) D5 D4 D3 D2 D1 D0 t(DH) t(DSU) SCLK t(SLOADH) t(SLOADS) SEN RESET T0109-03 Figure 4. Serial Interface Timing 18 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 SERIAL INTERFACE TIMING CHARACTERISTICS Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3V, unless otherwise noted. PARAMETER MIN TYP > DC MAX UNIT 20 MHz fSCLK SCLK Frequency, fSCLK = 1/tSCLK tSLOADS SEN to SCLK Setup time 25 ns tSLOADH SCLK to SEN Hold time 25 ns tDSU SDATA Setup time 25 ns tDH SDATA Hold time 25 ns 100 ns Time taken for register write to take effect after 16th SCLK falling edge RESET TIMING Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = LVDD = 3.3V, unless otherwise noted. PARMATER CONDITIONS MIN t1 Power-on delay time Delay from power-up of AVDD and LVDD to RESET pulse active t2 Reset pulse width Pulse width of active RESET signal t3 Register write delay time Delay from RESET disable to SEN active tPO Power-up delay time TYP UNIT 5 ms 10 ns 25 Delay from power-up of AVDD and LVDD to output stable MAX ns 6.5 ms Power Supply AVDD, LVDD t1 RESET t2 t3 SEN T0108-03 Figure 5. Reset Timing Submit Documentation Feedback 19 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 SERIAL REGISTER MAP Table 12. Summary of Functions Supported By Serial Interface REGISTER ADDRESS A4 - A0 REGISTER FUNCTIONS (1) (2) D10 D9 D8 D7 00 <RST> S/W RESET 0 0 0 04 0 0 0 0 0 <DF> DATA FORMAT 2S COMP OR STRAIGHT BINARY 0 0A 0 0D 10 11 (1) (2) 20 D5 <REF> INTERNAL OR EXTERNAL D4 D3 <PDN CHD> POWER DOWN CH D <PDN CHC> POWER DOWN CHC D2 <PDN CHB> POWER DOWN CH B <CLKIN GAIN> INPUT CLOCK BUFFER GAIN CONTROL <PATTERNS> TEST PATTERNS 0 0 0 D1 D0 <PDN CHA> POWER DOWN CH A <PDN GLOBAL> GLOBAL POWER DOWN 0 0 0 0 <CUSTOM A> CUSTOM PATTERN (LOWER 11 BITS) 0B 0C D6 <FINE GAIN> FINE GAIN CONTROL (1dB to 6 dB) <OVRD> OVERRIDE BIT 0 0 0 0 0 0 0 BYTE-WISE OR BIT-WISE MSB OR LSB FIRST <COARSE GAIN> COURSE GAIN ENABLE FALLING OR RISING BIT CLOCK CAPTURE EDGE 0 <TERM CLK> LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS WORD-WISE CONTROL 0 0 <LVDS CURR> LVDS CURRENT SETTINGS 0 0 14-BIT OR 16-BIT SERIALIZE DDR OR SDR BIT CLOCK 1-WIRE OR 2-WIRE INTERFACE <CURR DOUBLE> LVDS CURRENT DOUBLE <TERM DATA> 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. Submit Documentation Feedback <CUSTOM B> CUSTOM PATTERN (UPPER 3 BITS) ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 DESCRIPTION OF SERIAL REGISTERS Table 13. Serial Register A REGISTER ADDRESS A4 - A0 00 BITS D10 <RST> S/W RESET D9 0 D8 0 D7 0 D6 D5 D4 D3 D2 D1 D0 0 <REF> INTERNAL OR EXTERNAL <PDN CHD> POWER DOWN CH D <PDN CHC> POWER DOWN CHC <PDN CHB> POWER DOWN CH B <PDN CHA> POWER DOWN CH A <PDN> GLOBAL POWER DOWN D0 - D4 Power down modes D0 <PDN GLOBAL> 0 Normal operation 1 Global power down, including all channels ADCs, internal references, internal PLL and output buffers D1 <PDN CHA> 0 CH A Powered up 1 CH A ADC Powered down D2 <PDN CHB> 0 CH B Powered up 1 CH B ADC Powered down D3 <PDN CHC> 0 CH C Powered up 1 CH C ADC Powered down D4 <PDN CHD> 0 CH D Powered up 1 CH D ADC Powered down D5 <REF> Reference 0 Internal reference enabled 1 External reference enabled D10 <RST> 1 Software reset applied – resets all internal registers and self-clears to 0 Submit Documentation Feedback 21 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Table 14. Serial Register B REGISTER ADDRESS A4 - A0 04 BITS D10 0 D9 0 D8 D7 0 D6 D5 D4 D3 D2 D1 D0 0 0 <CLKIN GAIN> INPUT CLOCK BUFFER GAIN CONTROL 0 D6 - D2 <CLKIN GAIN> 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 Table 15. Serial Register C REGISTER ADDRESS A4 - A0 00 BITS D10 D9 D8 0 <DF> DATA DORMAT 2S COMP OR STRAIGHT BINARY 0 D7 D6 D5 <PATTERNS> TEST PATTERNS D4 D3 D2 D1 D0 0 0 0 0 0 D7 - D5 <PATTERNS> 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 <DF> Data format selection 0 2s Complement format 1 Straight binary format 22 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 A> CUSTOM PATTERN (LOWER 11 BITS) 0B D10 - D0 <CUSTOM A> Lower 11 bits of custom pattern <D10>…<D0> Table 17. Serial Register E REGISTER ADDRESS A4 - A0 0C BITS D10 D9 D8 <FINE GAIN> FINE GAIN CONTROL (1 dB to 6 dB) D7 D6 0 D5 0 D4 0 0 D3 0 D4 - D0 <CUSTOM B> Upper 3 bits of custom pattern <D13>…<D11> D10-D8 <FINE GAIN> 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) <CUSTOM B> CUSTOM PATTERN (UPPER 3 BITS) Table 18. Serial Register F REGISTER ADDRESS A4 - A0 0D BITS D10 <OVRD> OVER-RIDE BITE D9 0 D8 0 D7 BYTE-WISE OR BIT-WISE D6 MSB OR LSB FIRST D5 D4 D3 D2 D1 D0 <COARSE GAIN> COURSE GAIN ENABLE FALLING OR RISING BIT CLOCK CAPTURE EDGE 0 14-BIT OR 16-BIT SERIALIZE DDR OR SDR BIT CLOCK 1-WIRE OR 2-WIRE INTERFACE D0 Interface selection 0 1 Wire interface 1 2 Wire interface D1 Bit clock selection (only in 2-wire interface) 0 DDR Bit clock 1 SDR Bit clock D2 Serialization factor selection 0 14X Serialization 1 16X Serialization D4 Bit clock capture edge (only when SDR bit clock is selected, D1 = 1) 0 Capture data with falling edge of bit clock 1 Capture data with rising edge of bit clock Submit Documentation Feedback 23 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 D5 <COARSE GAIN>Coarse gain control 0 0 dB Coarse gain (full-scale range = 2.0 VPP) 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 <OVRD> Over-ride bit. All the functions in register 0x0D can also be controlled using the parallel control pins. By setting bit <OVRD> = 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 10 BITS D10 D9 D8 D7 D6 D5 <TERM CLK> LVDS INTERNAL TERMINATION BIT AND WORD CLOCKS D4 D3 D2 <LVDS CURR> LVDS CURRENT SETTINGS D0 <CURR DOUBLE> LVDS current double for data outputs 0 Nominal LVDS current, as set by <D5…D2> 1 Double the nominal value D1 <CURR DOUBLE> LVDS current double for bit and word clock outputs 0 Nominal LVDS current, as set by <D5…D2> 1 Double the nominal value D3-D2 <LVDS CURR> LVDS current setting for data outputs 00 3.5 mA 01 4 mA 10 2.5 mA 11 3 mA D5-D4 <LVDS CURR> 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 <TERM CLK> LVDS internal termination for bit and word clock outputs 00000 No internal termination 00001 166 Ω 24 Submit Documentation Feedback D1 D0 <LVDS DOUBLE> LVDS CURRENT DOUBLE ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 <TERM DATA> LVDS INTERNAL TERMINATION - DATA OUTPUTS D4-D0 <TERM DATA> 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 Submit Documentation Feedback 25 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 PIN CONFIGURATION (2-WIRE INTERFACE) LVDD DC1_P DC1_M DC0_P LGND DC0_M FCLKP FCLKM DCLKP DCLKM LGND DB1_P DB1_M DB0_P LVDD DB0_M ADS644x 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 37 IND_P 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 NC AVDD AVDD 12 AGND AGND INA_P CFG1 IND_M CFG2 38 CFG3 11 AVDD INA_M AGND AGND CLKM 39 CLKP 10 AGND AGND VCM AVDD CFG4 40 AVDD 9 AGND AVDD P0056-04 PIN ASSIGNMENTS (2-WIRE INTERFACE) PINS NAME NO. I/O NO. OF PINS DESCRIPTION SUPPLY AND GROUND PINS AVDD 9,17,19,27,3 2,40 6 Analog power supply AGND 8,10,13,16,1 8, 23, 26,31,33,36, 39 11 Analog ground LVDD 7,49,64 3 Digital power supply LGND 54,59 2 Digital ground 2 Differential input clock pair INPUT PINS CLKP, CLKM 26 24,25 I Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 PIN ASSIGNMENTS (2-WIRE INTERFACE) (continued) PINS NAME NO. I/O NO. OF PINS DESCRIPTION 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. 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. RESET 6 I 1 When using the serial interface mode, the user MUST initialize internal registers through hardware RESET by applying a high-going pulse on this pin or by using software reset option. Refer to the Serial Interface section. In parallel interface mode, tie RESET permanently high. (SCLK, SDATA and SEN function as parallel control pins in this mode). The pin has an internal pull-down resistor to ground. 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 14x or 16x serialization and SDR bit clock capture edge. Refer to Table 9 for description. For 14x 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. 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 1 Do Not Connect OUTPUT PINS DA0_P,DA0_M NC 20 Submit Documentation Feedback 27 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 PIN ASSIGNMENTS (2-WIRE INTERFACE) (continued) PINS NAME PAD 28 NO. 0 I/O NO. OF PINS DESCRIPTION 1 Connect to ground plane using multiple vias. Refer to Board Design Considerations in the application section. Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 ADS644x RGC PACKAGE (TOP VIEW) UNUSED 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 1 48 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 37 IND_P 13 36 AGND INB_M 14 35 INC_M INB_P 15 34 INC_P AGND 16 33 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 AGND AVDD AVDD AVDD 12 AGND AGND INA_P CFG1 IND_M CFG2 38 CFG3 11 AVDD INA_M AGND AGND CLKM 39 CLKP 10 AGND AGND VCM AVDD CFG4 40 NC 9 AGND AVDD P0056-05 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 2 Differential input clock pair INPUT PINS CLKP, CLKM 24,25 I Submit Documentation Feedback 29 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 PIN ASSIGNMENTS (1-WIRE INTERFACE) (continued) PINS NAME NO. I/O NO. OF PINS DESCRIPTION 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. 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 capacitance 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. RESET 6 I 1 When using the serial interface mode, the user MUST initialize internal registers through hardware RESET by applying a high-going pulse on this pin or by using software reset option. Refer to the Serial Interface section. In parallel interface mode, tie RESET permanently high. (SCLK, SDATA and SEN function as parallel control pins in this mode). The pin has an internal pull-down resistor to ground. 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 14x or 16x serialization and SDR bit clock capture edge. Refer to Table 9 for description. For 14x 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. Refer to Board Design Considerations in the application section. OUTPUT PINS UNUSED 30 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 (unless otherwise noted) ADS6445 (Fsrated = 125 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 100 MHz INPUT SIGNAL 0 0 SFDR = 88 dBc SINAD = 74 dBFS SNR = 74.3 dBFS THD = 87.6 dBc −20 −40 Amplitude − dB Amplitude − dB −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 50 60 f − Frequency − MHz 0 10 20 30 40 50 60 f − Frequency − MHz G001 G002 Figure 6. Figure 7. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 0 SFDR = 77.9 dBc SINAD = 68 dBFS SNR = 69.2 dBFS THD = 75.3 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –86 dBFS SFDR = –95 dBFS −20 −40 Amplitude − dB −40 Amplitude − dB SFDR = 86 dBc SINAD = 72.63 dBFS SNR = 72.76 dBFS THD = 85 dBc −20 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 f − Frequency − MHz 50 60 0 G003 Figure 8. 10 20 30 40 f − Frequency − MHz 50 60 G004 Figure 9. Submit Documentation Feedback 31 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6445 (Fsrated = 125 MSPS) (continued) SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 92 75 90 74 Gain = 3.5 dB 73 86 SNR − dBFS 84 82 80 Gain = 0 dB 72 71 70 Gain = 3.5 dB 69 78 Gain = 0 dB 76 68 74 67 0 50 100 150 200 250 fIN − Input Frequency − MHz 0 50 100 G005 Figure 10. SFDR vs INPUT FREQUENCY ACROSS GAINS G006 SINAD vs INPUT FREQUENCY ACROSS GAINS Input adjusted to get −1dBFS input 3.5 dB 73 88 SINAD − dBFS 4 dB 86 0 dB 74 6 dB SFDR − dBc 250 75 90 5 dB 84 3 dB 82 80 2 dB 1 dB 72 3 dB 71 70 69 68 2 dB 78 76 0 dB 67 4 dB 66 1 dB 74 5 dB 6 dB 65 10 30 50 70 90 110 130 150 170 190 210 230 Fin − Input Frequency − MHz 20 40 60 80 PERFORMANCE vs AVDD PERFORMANCE vs LVDD 77 SFDR 94 76 82 75 80 74 SNR 78 73 76 72 74 71 3.1 3.2 3.3 3.4 AVDD − Supply Voltage − V 3.5 75 fIN = 50.1 MHz AVDD = 3.3 V 74 SNR SFDR − dBc 84 72 3.0 98 78 SNR − dBFS 86 G008 Figure 13. 88 fIN = 50.1 MHz LVDD = 3.3 V 100 120 140 160 180 200 220 Fin − Input Frequency − MHz G007 Figure 12. SFDR − dBc 200 Figure 11. 92 90 73 86 72 SFDR 82 78 3.0 70 3.6 G009 Figure 14. 32 150 fIN − Input Frequency − MHz 71 3.1 3.2 3.3 3.4 LVDD − Supply Voltage − V Figure 15. Submit Documentation Feedback SNR − dBFS SFDR − dBc 88 3.5 70 3.6 G010 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6445 (Fsrated = 125 MSPS) (continued) PERFORMANCE vs TEMPERATURE PERFORMANCE vs INPUT AMPLITUDE 84 76 110 100 SFDR 75 80 SNR − dBFS 74 SNR 78 73 76 72 90 0 20 40 60 75 SNR (dBFS) 70 74 60 73 50 72 SFDR (dBc) 40 71 fIN = 20 MHz 30 −60 71 −20 76 80 fIN = 50.1 MHz 74 −40 77 SFDR (dBFS) 80 T − Temperature − °C −50 −40 −20 −10 70 0 Input Amplitude − dBFS G011 Figure 16. G012 Figure 17. PERFORMANCE vs CLOCK AMPLITUDE (differential) 86 PERFORMANCE vs CLOCK DUTY CYCLE 90 77 78 fIN = 50.1 MHz SFDR 84 76 75 80 74 78 73 SNR 76 72 74 71 SFDR − dBc 82 SNR − dBFS SFDR SFDR − dBc −30 89 77 88 76 87 75 86 74 SNR − dBFS SFDR − dBc 82 78 SNR − dBFS 77 SFDR − dBc, dBFS 86 SNR 85 73 fIN = 20.1 MHz 72 0.5 1.0 1.5 2.0 70 3.0 2.5 84 Input Clock Amplitude − VPP 40 45 50 55 60 65 Input Clock Duty Cycle − % G013 Figure 18. Figure 19. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 2.0 40 1.8 35 G014 RMS LSB = 1.064 1.6 30 1.4 Occurence − % PD − Power Dissipation − W 72 35 1.2 1.0 AVDD 0.8 0.6 25 20 15 10 0.4 LVDD 5 0.2 0 0.0 0 25 50 75 100 fS − Sampling Frequency − MSPS 125 8187 8188 8189 8190 8191 8192 8193 8194 8195 8196 G015 Figure 20. Output Code G016 Figure 21. Submit Documentation Feedback 33 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6445 (Fsrated = 125 MSPS) (continued) CMRR vs FREQUENCY 78 fIN = 50.1 MHz External Reference Mode 76 90 74 SNR 88 72 SNR − dBFS SFDR − dBc 92 SFDR 86 84 1.30 70 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 68 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 94 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 G017 Figure 22. 34 50 100 150 Figure 23. Submit Documentation Feedback 200 f − Frequency − MHz 250 300 G018 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6444 (Fsrated = 105 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 70 MHz INPUT SIGNAL 0 SFDR = 91.2 dBc SINAD = 73.9 dBFS SNR = 74.1 dBFS THD = 89.7 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 40 50 G020 Figure 24. Figure 25. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 SFDR = 81 dBc SINAD = 68.6 dBFS SNR = 69 dBFS THD = 79 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –88 dBFS SFDR = –89 dBFS −20 −40 Amplitude − dB −40 −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 f − Frequency − MHz G021 Figure 26. 50 G022 Figure 27. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 92 76 90 75 74 86 SNR − dBFS 88 SFDR − dBc 30 f − Frequency − MHz G019 0 Amplitude − dB SFDR = 81.2 dBc SINAD = 71.6 dBFS SNR = 72.6 dBFS THD = 79.9 dBc −20 Amplitude − dB −40 Amplitude − dB 0 Gain = 3.5 dB 84 82 73 72 Gain = 0 dB 71 70 Gain = 3.5 dB 69 80 68 Gain = 0 dB 78 67 76 66 0 50 100 150 fIN − Input Frequency − MHz 200 250 0 G023 Figure 28. 50 100 150 fIN − Input Frequency − MHz 200 250 G024 Figure 29. Submit Documentation Feedback 35 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6444 (Fsrated = 105 MSPS) (continued) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 92 75 Input adjusted to get −1dBFS input 90 88 SINAD − dBFS 84 6 dB 80 2 dB 78 70 69 67 66 74 65 30 50 70 90 3 dB 71 76 10 2 dB 68 1 dB 0 dB 1 dB 72 20 110 130 150 170 190 210 230 Fin − Input Frequency − MHz 4 dB 40 5 dB 60 80 6 dB 100 120 140 160 180 200 220 Fin − Input Frequency − MHz G025 Figure 30. Figure 31. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 88 fIN = 70.1 MHz LVDD = 3.3 V 77 94 75 fIN = 70.1 MHz AVDD = 3.3 V 74 SFDR 82 75 80 74 78 73 76 72 SNR 74 SNR 90 86 72 SFDR 82 3.1 3.2 3.3 3.4 78 3.0 70 3.6 3.5 3.1 3.2 PERFORMANCE vs TEMPERATURE 76 75 80 74 SNR 78 73 76 SNR − dBFS SFDR − dBc SFDR 82 G028 71 60 110 90 100 85 90 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 40 fIN = 70.1 MHz T − Temperature − °C 70 3.6 SFDR (dBc) 72 40 SFDR − dBc, dBFS 84 20 3.5 PERFORMANCE vs INPUT AMPLITUDE 77 0 3.4 Figure 33. 86 −20 3.3 LVDD − Supply Voltage − V G027 Figure 32. 30 −60 80 G029 Figure 34. 36 71 71 AVDD − Supply Voltage − V 74 −40 73 SNR − dBFS 76 SFDR − dBc SFDR − dBc 84 72 3.0 98 78 SNR − dBFS 86 G026 SNR − dBFS SFDR − dBc 3 dB 82 3.5 dB 73 5 dB 86 0 dB 74 4 dB 55 fIN = 20 MHz −50 −40 −30 −20 Input Amplitude − dBFS Figure 35. Submit Documentation Feedback −10 50 0 G030 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6444 (Fsrated = 105 MSPS) (continued) PERFORMANCE vs CLOCK AMPLITUDE (differential) 92 PERFORMANCE vs CLOCK DUTY CYCLE 93 76 fIN = 70.1 MHz 90 76 fIN = 20.1 MHz 75 91 88 75 SFDR 74 72 82 71 80 74 SNR 87 70 SFDR 78 85 1.0 1.5 2.0 72 83 68 3.0 2.5 71 35 Input Clock Amplitude − VPP 40 45 50 55 60 65 Input Clock Duty Cycle − % G031 G032 Figure 36. Figure 37. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 2.0 40 1.8 35 RMS LSB = 1.054 1.6 30 Occurence − % 1.4 1.2 1.0 AVDD 0.8 0.6 25 20 15 10 LVDD 0.4 5 0.2 0 0.0 0 20 40 60 80 8179 8180 8181 8182 8183 8184 8185 8186 8187 8188 100 fS − Sampling Frequency − MSPS G033 Output Code Figure 38. CMRR vs FREQUENCY 76 fIN = 70.1 MHz External Reference Mode 74 SNR 82 72 70 SFDR 81 80 1.30 SNR − dBFS 84 68 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 66 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 83 G034 Figure 39. 85 SFDR − dBc 73 69 76 0.5 PD − Power Dissipation − W 89 SNR − dBFS 84 SFDR − dBc 73 SNR − dBFS SFDR − dBc SNR 86 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 G035 Figure 40. 50 100 150 200 f − Frequency − MHz 250 300 G018 Figure 41. Submit Documentation Feedback 37 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6443 (Fsrated = 80 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 70 MHz INPUT SIGNAL 0 SFDR = 91 dBc SINAD = 74.2 dBFS SNR = 74.4 dBFS THD = 88.5 dBc −20 −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 f − Frequency − MHz 0 10 40 G038 Figure 43. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 SFDR = 82 dBc SINAD = 69.4 dBFS SNR = 69.7 dBFS THD = 83.4 dBc fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –93 dBFS SFDR = –98 dBFS −20 −40 Amplitude − dB −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 40 f − Frequency − MHz 0 10 G039 SFDR vs INPUT FREQUENCY 40 G040 SNR vs INPUT FREQUENCY 94 75 92 74 90 73 SNR − dBFS 76 Gain = 3.5 dB 86 84 82 30 Figure 45. 96 88 20 f − Frequency − MHz Figure 44. SFDR − dBc 30 Figure 42. −20 Gain = 0 dB 72 71 Gain = 3.5 dB 70 69 Gain = 0 dB 80 68 78 67 76 66 0 50 100 150 fIN − Input Frequency − MHz 200 250 0 G041 Figure 46. 38 20 f − Frequency − MHz G037 0 Amplitude − dB SFDR = 85.7 dBc SINAD = 73 dBFS SNR = 73.5 dBFS THD = 83.9 dBc −20 Amplitude − dB −40 Amplitude − dB 0 50 100 150 fIN − Input Frequency − MHz Figure 47. Submit Documentation Feedback 200 250 G042 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6443 (Fsrated = 80 MSPS) (continued) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 94 75 Input adjusted to get −1dBFS input 92 74 4 dB 5 dB 86 84 6 dB 2 dB 3 dB 72 0 dB 70 69 68 80 67 1 dB 78 4 dB 5 dB 66 0 dB 76 6 dB 65 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 G043 Figure 48. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 92 78 90 77 91 76 90 SFDR 88 75 86 74 SFDR − dBc fIN = 50.1 MHz LVDD = 3.3 V SNR − dBFS 92 G044 Figure 49. 94 SFDR − dBc 3.5 dB 71 76 fIN = 50.1 MHz AVDD = 3.3 V 75 SNR 74 89 73 88 72 SNR − dBFS SFDR − dBc 88 82 1 dB 73 3 dB SINAD − dBFS 90 2 dB SFDR SNR 82 3.0 3.1 3.2 3.3 87 73 3.4 86 3.0 72 3.6 3.5 AVDD − Supply Voltage − V 71 3.1 3.2 3.4 3.5 70 3.6 LVDD − Supply Voltage − V G045 Figure 50. G046 Figure 51. PERFORMANCE vs TEMPERATURE 92 PERFORMANCE vs INPUT AMPLITUDE 110 78 fIN = 50.1 MHz 76 86 75 SNR 84 SFDR − dBc, dBFS SFDR 88 90 100 77 SNR − dBFS 90 SFDR − dBc 3.3 90 85 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 74 SFDR (dBc) 40 82 −40 30 −60 73 −20 0 20 40 T − Temperature − °C 60 SNR − dBFS 84 80 G047 Figure 52. 55 fIN = 20 MHz −50 −40 −30 −20 Input Amplitude − dBFS −10 50 0 G048 Figure 53. Submit Documentation Feedback 39 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6443 (Fsrated = 80 MSPS) (continued) PERFORMANCE vs CLOCK AMPLITUDE (differential) 92 fIN = 50.1 MHz 76 92 77 90 86 75 84 74 SNR 82 73 80 SFDR − dBc 76 SFDR SNR − dBFS 88 75 SFDR 88 74 86 73 SNR 72 84 78 1.0 1.5 2.0 fIN = 20.1 MHz 70 3.0 2.5 82 35 Input Clock Amplitude − VPP 40 45 50 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 = 1.016 1.6 30 1.4 1.2 1.0 AVDD 0.8 0.6 25 20 15 10 0.4 LVDD 5 0 0.0 0 20 40 60 8180 8181 8182 8183 8184 8185 8186 8187 8188 8189 80 fS − Sampling Frequency − MSPS G051 Output Code Figure 56. CMRR vs FREQUENCY 76 fIN = 50.1 MHz External Reference Mode 74 SNR 72 SFDR 90 70 88 86 1.30 SNR − dBFS 94 68 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 66 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 92 G052 Figure 57. 96 SFDR − dBc 71 65 60 Figure 54. 0.2 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 G053 Figure 58. 40 55 Input Clock Duty Cycle − % G049 Occurence − % PD − Power Dissipation − W 72 71 76 0.5 SNR − dBFS 90 SFDR − dBc PERFORMANCE vs CLOCK DUTY CYCLE 78 50 100 150 Figure 59. Submit Documentation Feedback 200 f − Frequency − MHz 250 300 G018 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6442 (Fsrated = 65 MSPS) FFT for 10 MHz INPUT SIGNAL FFT for 50 MHz INPUT SIGNAL 0 SFDR = 92.4 dBc SINAD = 74.3 dBFS SNR = 74.5 dBFS THD = 90 dBc −20 −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 0 10 30 G056 Figure 60. Figure 61. FFT for 230 MHz INPUT SIGNAL INTERMODULATION DISTORTION (IMD) vs FREQUENCY 0 SFDR = 82.1 dBc SINAD = 69.3 dBFS SNR = 69.7 dBFS THD = 81.2 dBc −20 fIN1 = 185.1 MHz, –7 dBFS fIN2 = 190.1 MHz, –7 dBFS 2-Tone IMD = –96 dBFS SFDR = –86 dBFS −20 −40 Amplitude − dB −40 −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 10 20 30 f − Frequency − MHz 0 10 G057 30 G058 Figure 63. SFDR vs INPUT FREQUENCY SNR vs INPUT FREQUENCY 96 76 94 75 92 74 SNR − dBFS 90 88 20 f − Frequency − MHz Figure 62. SFDR − dBc 20 f − Frequency − MHz G055 0 Amplitude − dB SFDR = 88.8 dBc SINAD = 73.6 dBFS SNR = 73.9 dBFS THD = 86.6 dBc −20 Amplitude − dB −40 Amplitude − dB 0 Gain = 3.5 dB 86 84 Gain = 0 dB 73 72 71 Gain = 3.5 dB 70 82 80 69 Gain = 0 dB 68 78 76 67 0 50 100 150 fIN − Input Frequency − MHz 200 250 0 G059 Figure 64. 50 100 150 fIN − Input Frequency − MHz 200 250 G060 Figure 65. Submit Documentation Feedback 41 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6442 (Fsrated = 65 MSPS) (continued) SFDR vs INPUT FREQUENCY ACROSS GAINS SINAD vs INPUT FREQUENCY ACROSS GAINS 96 75 Input adjusted to get −1dBFS input 94 92 SINAD − dBFS 3 dB 4 dB 88 86 84 6 dB 82 3.5 dB 2 dB 72 3 dB 0 dB 71 70 69 68 1 dB 80 67 2 dB 78 4 dB 5 dB 66 0 dB 76 6 dB 65 30 50 70 90 110 130 150 170 190 210 230 Fin − Input Frequency − MHz 20 40 60 80 100 120 140 160 180 200 220 Fin − Input Frequency − MHz G061 Figure 66. Figure 67. PERFORMANCE vs AVDD PERFORMANCE vs LVDD 92 78 90 SFDR 88 77 91 76 90 75 86 74 SFDR − dBc fIN = 50.1 MHz LVDD = 3.3 V SNR − dBFS 94 92 G062 76 fIN = 50.1 MHz AVDD = 3.3 V 75 SNR 74 89 73 SFDR 88 72 SNR − dBFS 10 SFDR − dBc 1 dB 73 5 dB 90 SFDR − dBc 74 SNR 84 3.1 3.2 3.3 3.4 86 3.0 72 3.6 3.5 AVDD − Supply Voltage − V 71 3.1 3.2 PERFORMANCE vs TEMPERATURE 76 88 75 SNR 86 SFDR − dBc, dBFS 90 90 100 SNR − dBFS 77 90 85 SFDR (dBFS) 80 80 70 75 SNR (dBFS) 70 60 65 50 60 SFDR (dBc) 74 40 55 fIN = 50.1 MHz 73 0 20 40 T − Temperature − °C 60 30 −60 80 G065 Figure 70. 42 G064 110 78 SFDR −20 70 3.6 PERFORMANCE vs INPUT AMPLITUDE 79 92 84 −40 3.5 Figure 69. 96 SFDR − dBc 3.4 LVDD − Supply Voltage − V G063 Figure 68. 94 3.3 SNR − dBFS 82 3.0 87 73 fIN = 20 MHz −50 −40 −30 −20 Input Amplitude − dBFS Figure 71. Submit Documentation Feedback −10 50 0 G066 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 ADS6442 (Fsrated = 65 MSPS) (continued) PERFORMANCE vs CLOCK AMPLITUDE (differential) 96 fIN = 50.1 MHz 95 76 93 75 79 78 SFDR 77 SFDR 88 76 86 75 SFDR − dBc 90 SNR − dBFS 92 91 SNR − dBFS 94 SFDR − dBc PERFORMANCE vs CLOCK DUTY CYCLE 80 74 89 73 SNR 84 74 SNR 82 87 80 0.5 1.0 1.5 2.0 fIN = 20.1 MHz 85 72 3.0 2.5 71 35 Input Clock Amplitude − VPP 40 45 50 60 65 G068 Figure 72. Figure 73. POWER DISSIPATION vs SAMPLING FREQUENCY OUTPUT NOISE HISTOGRAM WITH INPUTS TIED TO COMMON-MODE 2.0 40 1.8 35 RMS LSB = 1.027 1.6 30 1.4 1.2 1.0 0.8 AVDD 0.6 25 20 15 10 0.4 LVDD 5 0.2 0 0.0 0 10 20 30 40 50 8189 8190 8191 8192 8193 8194 8195 8196 8197 60 fS − Sampling Frequency − MSPS G069 Output Code Figure 74. CMRR vs FREQUENCY 76 fIN = 50.1 MHz External Reference Mode 94 74 92 72 70 SFDR 88 86 1.30 SNR − dBFS SNR 68 1.35 1.40 1.45 1.50 1.55 VVCM − VCM Voltage − V 1.60 1.65 66 1.70 CMRR − Common-Mode Rejection Ratio − dBc PERFORMANCE IN EXTERNAL REFERENCE MODE 90 G070 Figure 75. 96 SFDR − dBc 55 Input Clock Duty Cycle − % G067 Occurence − % PD − Power Dissipation − W 72 73 0 −10 −20 −30 −40 −50 −60 −70 −80 −90 −100 0 G071 Figure 76. 50 100 150 200 f − Frequency − MHz 250 300 G018 Figure 77. Submit Documentation Feedback 43 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Contour Plots across Input and Sampling Frequencies 125 120 92 89 80 86 83 fS - Sampling Frequency - MSPS 110 65 86 80 83 89 74 100 77 83 90 86 80 86 83 80 70 68 71 74 86 89 80 60 68 71 77 65 83 50 89 86 30 10 83 50 74 80 150 100 68 71 77 40 200 250 300 65 400 350 450 500 fIN - Input Frequency - MHz 65 75 70 80 85 90 SFDR - dBc M0049-13 Figure 78. SFDR Contour (no gain) 125 120 85 88 70 76 82 110 fS - Sampling Frequency - MSPS 79 91 91 88 88 100 73 79 85 94 82 90 76 82 88 80 70 91 70 60 67 73 79 85 88 76 50 70 82 40 91 30 10 79 85 50 150 100 200 73 76 250 300 350 400 450 500 fIN - Input Frequency - MHz 65 70 75 80 85 SFDR - dBc Figure 79. SFDR Contour (3.5dB coarse gain) 44 Submit Documentation Feedback 90 M0049-14 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Contour Plots across Input and Sampling Frequencies (continued) 125 120 68 fS - Sampling Frequency - MSPS 73 74 110 64 67 72 70 71 65 66 69 100 90 66 80 70 72 73 74 71 64 65 67 68 69 70 60 66 64 65 50 67 40 30 10 50 69 71 70 72 73 74 150 100 68 66 200 250 64 65 300 63 400 350 62 450 500 fIN - Input Frequency - MHz 60 70 65 75 SNR - dBFS M0048-13 Figure 80. SNR Contour (no gain) 125 120 72 71 fS - Sampling Frequency - MSPS 110 70 67 68 69 66 65 100 90 67 71 80 68 72 70 70 65 69 66 64 60 50 71 67 72 69 40 30 10 70 50 100 150 66 68 200 250 64 65 64 300 63 62 63 400 350 61 450 500 fIN - Input Frequency - MHz 60 62 64 66 68 SNR - dBFS 70 72 M0048-14 Figure 81. SNR Contour (3.5dB coarse gain) Submit Documentation Feedback 45 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION THEORY OF OPERATION The ADS6445/ADS6444/ADS6443/ADS6442 (ADS644X) is a family of quad channel, 14-bit pipeline ADC based on switched capacitor architecture in CMOS technology. The conversion is initiated simultaneously by all the four channels at the rising edge of the external input clock. After the input signals are captured by the sample and hold circuit of each channel, the samples are sequentially converted by a series of low resolution stages. The stage outputs are combined in a digital correction logic block to form the final 14-bit word with a latency of 12 clock cycles. The 14-bit word of each channel is serialized and output as LVDS levels. In addition to the data streams, a bit clock and frame clock are also output. The frame clock is aligned with the 14-bit word boundary. ANALOG INPUT The analog input consists of a switched-capacitor based differential sample and hold architecture, shown in Figure 82. This differential topology results in very good AC performance even for high input frequencies. The INP and INM pins have to be externally biased around a common-mode voltage of 1.5 V, available on VCM pin 13. For a full-scale differential input, each input pin INP, INM has to swing symmetrically between VCM + 0.5 V and VCM – 0.5 V, resulting in a 2-VPP differential input swing. The maximum swing is determined by the internal reference voltages REFP (2.0 V nominal) and REFM (1.0 V, nominal). The sampling circuit has a 3 dB bandwidth that extends up to 500 MHz (see Figure 83, shown by the transfer function from the analog input pins to the voltage across the sampling capacitors, TF_ADC). Sampling Switch Lpkg 6 nH 25 W Sampling Capacitor RCR Filter INP Cbond 2 pF 50 W Resr 200 W Lpkg 6 nH 3.2 pF Cpar2 Ron 1 pF 15 W Cpar1 0.8 pF Ron 10 W 50 W Ron 15 W 25 W INM Cpar2 1 pF Cbond 2 pF Resr 200 W Csamp 4.0 pF Csamp 4.0 pF Sampling Capacitor Sampling Switch S0237-01 Figure 82. Input Sampling Circuit 46 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) 1 Magnitude − dB 0 −1 −2 −3 −4 −5 −6 0 100 200 300 400 500 fIN − Input Frequency − MHz 600 700 G073 Figure 83. Analog Input Bandwidth (represented by magnitude of TF_ADC, see Figure 85 ) Drive Circuit Requirements For optimum performance, the analog inputs must be driven differentially. This improves the common-mode noise immunity and even order harmonic rejection. A 5-Ω resistor in series with each input pin is recommended to damp out ringing caused by the package parasitics. It is also necessary to present low impedance (< 50 Ω) for the common mode switching currents. For example, this is achieved by using two resistors from each input terminated to the common mode voltage (VCM). In addition to the above, the drive circuit may have to be designed to provide a low insertion loss over the desired frequency range and matched impedance to the source. While doing this, the ADC input impedance has to be taken into account. Figure 84 shows that the impedance (Zin, looking into the ADC input pins) decreases at high input frequencies. The smith chart shows that the input impedance is capacitive and can be approximated by a series R-C upto 500 MHz. Submit Documentation Feedback 47 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) F1 Freq = 50 MHz S(1, 1) = 0.967 / –13.241 Impedance = 62.211 – j421.739 1000 F1 Frequency = 50 MHz Mag(Zin1) = 426.302 900 700 F2 Frequency = 400 MHz Mag(Zin1) = 65.193 600 F1 500 S(1, 1) Magnitude of Zin -- W 800 400 F2 300 200 F1 F2 100 0 0 50 100 150 200 250 300 350 400 450 500 fI -- Input Frequency -- MHz Frequency (100 kHz to 500 MHz) F2 Freq = 400 MHz S(1, 1) = 0.273 / –59.329 Impedance = 58.132 – j29.510 M0087-01 Figure 84. ADC Input Impedance, Zin Using RF-Transformers Based Drive Circuits Figure 85 shows a configuration using a single 1:1 turns ratio transformer (for example, Coilcraft WBC1-1) that can be used for low input frequencies up to 100 MHz. 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. 48 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) TF_ADC 0.1 mF ADS6xxx 5W INP 0.1 mF 25 W 25 W INM 5W 1:1 VCM S0256-01 Figure 85. Single Transformer Drive Circuit At high input frequencies, the mismatch in the transformer parasitic capacitance (between the windings) results in degraded even-order harmonic performance. Connecting two identical RF transformers back-to-back helps minimize this mismatch, and good performance is obtained for high frequency input signals. Figure 86 shows an example using two transformers (like Coilcraft WBC1-1). An additional termination resistor pair (enclosed within the shaded box in Figure 86) may be required between the two transformers to improve the balance between the P and M sides. The center point of this termination must be connected to ground. ADS6xxx 0.1 mF 5W INP 50 W 0.1 mF 50 W 50 W 50 W INM 1:1 1:1 5W VCM S0164-04 Figure 86. Two Transformer Drive Circuit Submit Documentation Feedback 49 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) Using Differential Amplifier Drive Circuits Figure 87 shows a drive ciruit using a differential amplifier (TI's THS4509) to convert a single-ended input to differential output that can be interfaced to the ADC input pins. In addition to the single-ended to differential conversion, the amplifier also provides gain (10 dB in Figure 87). 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 voltage of the ADC input spins is set using two resistors connected to VCM. The amplifier outputs can also be dc-coupled. Using the output common-mode control of the THS4509, the ADC input pins can be biased to 1.5 V. In this case, use +4 V and -1 V supplies for the THS4509 to ensure that 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 87. Drive Circuit using THS4509 Refer to the EVM User Guide (SLAU196) for more information. INPUT COMMON MODE To ensure a low-noise common-mode reference, the VCM pin is filtered with a 0.1-µF low-inductance capacitor connected to ground. The VCM pin is designed to directly drive the ADC inputs. The input stage of the ADC sinks a common-mode current in the order of 155 µA at 125 MSPS (per input pin). Equation 1 describes the dependency of the common-mode current and the sampling frequency. 155 mAxFs 125 MSPS (1) This equation helps to design the output capability and impedance of the CM driving circuit accordingly. 50 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) REFERENCE The ADS644X 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 <REF> (refer to Table 13). INTREF Internal Reference VCM 1 kW INTREF 4 kW EXTREF REFM REFP ADS6xxx S0165-04 Figure 88. Reference Section Internal Reference When the device is in internal reference mode, the REFP and REFM voltages are generated internally. Common-mode 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. Submit Documentation Feedback 51 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 APPLICATION INFORMATION (continued) COARSE GAIN AND PROGRAMMABLE FINE GAIN ADS644X 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 (as seen in Figure 10 and Figure 11). 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). 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 <COARSE GAIN> (refer to Table 18) and <FINE GAIN> (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 4 Fine setting (programmable) 1.42 1.26 5 1.12 6 1.00 CLOCK INPUT The ADS644X clock inputs can be driven differentially (SINE, LVPECL or LVDS) or single-ended (LVCMOS), with little or no difference in performance between them. The common-mode voltage of the clock inputs is set to VCM using internal 5-kΩ resistors as shown in Figure 89. This allows using transformer-coupled drive circuits for sine wave clock or ac-coupling for LVPECL, LVDS clock sources (see Figure 90 and Figure 92). 52 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 VCM VCM 5 kW 5 kW CLKP CLKM ADS6xxx S0166-04 Figure 89. Internal Clock Buffer 0.1 mF CLKP Differential Sine-Wave or PECL or LVDS Clock Input 0.1 mF CLKM ADS6xxx S0167-05 Figure 90. Differential Clock Driving Circuit Figure 91 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. Submit Documentation Feedback 53 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 91. 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 92. 0.1 mF CMOS Clock Input CLKP 0.1 mF CLKM ADS6xxx S0168-07 Figure 92. Single-Ended Clock Driving Circuit 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 non-50% 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. As shown by Figure 18, use clock amplitude greater than 1VPP 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 <CLKIN GAIN> (refer to Table 14) and increases monotonically from Gain 0 to Gain 4 settings. Table 22 lists the minimum clock amplitude supported for each gain setting. 54 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 (highest gain) 150 POWER DOWN MODES The ADS644X 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 <PDN GLOBAL> (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 <PDN CH> (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 mVPP, 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. Table 23. Power Down Modes Summary POWER DOWN MODE AVDD POWER (mW) LVDD POWER (mW) In power-up 1360 297 – Global power down 65 12 100 µs 1 Channel in standby 2 Channels in standby 825 (1) 3 Channels in standby 532 (1) 245 (1) 4 Channels in standby Input clock stop (1) (1) 1115 200 WAKE UP TIME 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. Submit Documentation Feedback 55 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 DIGITAL OUTPUT INTERFACE The ADS644X offers several flexible output options making it easy to interface to an ASIC or an FPGA. Each of these options can be easily programmed using either parallel pins or the serial interface. The output interface options are: • 1-Wire, 1× frame clock, 14× and 16× serialization with DDR bit clock • 2-Wire, 1× frame clock, 16× serialization, with DDR and SDR bit clock, byte wise/bit wise/word wise • 2-Wire, 1× frame clock, 14× serialization, with SDR bit clock, byte wise/bit wise/word wise • 2-Wire, (0.5 x) frame clock, 14× serialization, with DDR bit clock, byte wise/bit wise/word wise The maximum sampling frequency, bit clock frequency and output data rate will vary depending on the interface options selected (refer to Table 12). Table 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 1-Wire DDR Bit clock 14× Serialization 65 455 65 910 16× Serialization 65 520 65 1040 2-Wire DDR Bit clock 14× Serialization 125 437.5 62.5 875 16× Serialization 125 500 125 1000 2-Wire SDR Bit clock 14× Serialization 65 455 65 910 16× Serialization 65 520 65 1040 Each interface option is described in detail in the following sections. 1-WIRE INTERFACE - 14× AND 16× SERIALIZATION WITH DDR BIT CLOCK Here the device outputs the data of each ADC serially on a single LVDS pair (1-wire). The data is available at the rising and falling edges of the bit clock (DDR bit clock). The ADC outputs a new word at the rising edge of every frame clock, starting with the MSB. Optionally, it can also be programmed to output the LSB first. The data rate is 14 × sample frequency (14× serialization) and 16 × sample frequency (16× serialization). 56 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Input Clock, CLKP/M Freq = Fs 16-Bit Serialization (1) 12-Bit Serialization Frame Clock, FCLKP Freq = 1 ´ Fs Bit Clock – DDR, DCLKP/M Freq = 7 ´ Fs Output Data DA, DB, DC, DD Data Rate = 14 ´ Fs D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D8 (D7) D7 (D8) D5 (D8) D4 (D9) D3 D2 D1 D0 (D10) (D11) (D12) (D13) D13 (D0) D12 (D1) Bit Clock – DDR, DCLKP/M Freq = 8 ´ Fs Output Data DA, DB, DC, DD Data Rate = 16 ´ Fs 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D6 D5 D4 D3 D2 (D9) (D10) (D11) (D12) (D13) D1 (0) Sample N D0 (0) 0 (D0) 0 (D1) Sample N + 1 Data Bit in MSB First Mode D13 (D2) Data Bit in LSB First Mode (1) In 16-Bit serialization, two zero bits are padded to the 14-bit ADC data on the MSB side. T0225-02 Figure 93. 1-Wire Interface 2-WIRE INTERFACE - 16× SERIALIZATION WITH DDR/SDR BIT CLOCK The 2-wire interface is recommended for sampling frequencies above 65 MSPS. In 16× serialization, two zero bits are padded to the 14-bit ADC data on the MSB side and the combined 16-bit data is serialized and output over two LVDS pairs. The data rate is 8 × Sample frequency since 8 bits are sent on each wire every clock cycle. The data is available along with DDR bit clock or optionally with SDR bit clock. Each ADC sample is sent over the 2 wires as byte-wise or bit-wise or word-wise. Using the 16× serialization makes it possible to upgrade to a 16-bit ADC in the future seamlessly, without requiring any modification to the receiver capture logic design. Submit Documentation Feedback 57 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Input Clock, CLKP/M Freq = Fs Frame Clock, FCLKP/M Freq = 1 ´ Fs Bit Clock – SDR, DCLKP/M Freq = 8 ´ Fs In Byte-Wise Mode Bit Clock – DDR, DCLKP/M Freq = 4 ´ Fs Output Data DA0, DB0, DC0, DD0 D7 (D0) D6 (D1) D5 (D2) D4 (D3) D3 (D4) D2 (D5) D1 (D6) D0 (D7) D7 (D0) D6 (D1) D5 (D2) D4 (D3) D3 (D4) D2 (D5) D1 (D6) D0 (D7) Output Data DA1, DB1, DC1, DD1 0 (D8) 0 (D9) D13 D12 D11 D10 D9 (0) D8 (0) 0 (D8) 0 (D9) D13 D12 D11 D10 (D10) (D11) (D12) (D13) (D10) (D11) (D12) (D13) D9 (0) D8 (0) D0 (0) 0 (D0) D12 (D2) D10 (D4) D8 (D6) D6 (D8) D2 D0 (D10) (D12) D1 (0) 0 (D1) D13 (D3) D11 (D5) D9 (D7) D7 (D9) (D11) (D13) D5 D4 D3 In Word-Wise Mode In Bit-Wise Mode Data Rate = 8 ´ Fs Output Data DA0, DB0, DC0, DD0 0 (D0) D12 (D2) D10 (D4) D8 (D6) D6 (D8) (D10) (D12) Output Data DA1, DB1, DC1, DD1 0 (D1) D13 (D3) D11 (D5) D9 (D7) D7 (D9) (D11) (D13) Output Data DA0, DB0, DC0, DD0 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D8 (D7) D7 (D8) D6 (D9) (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 0 (D0) 0 (D1) D13 (D2) D12 (D3) D11 (D4) D10 (D5) D9 (D6) D8 (D7) D7 (D8) D6 (D9) (D10) (D11) (D12) (D13) D4 D5 D2 D3 Data Bit in MSB First Mode D5 D4 D3 D4 D5 D2 D2 D3 (0) D1 (0) D1 (0) D0 (0) D1 (0) D0 (0) White Cells – Sample N D13 (D3) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0226-02 Figure 94. 2-Wire Interface 16× Serialization 58 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 2-WIRE INTERFACE - 14× SERIALIZATION The 14-bit ADC data is serialized and output over two LVDS pairs. A frame clock at 1× sample frequency is also available with an SDR bit clock. With DDR bit clock option, the frame clock frequency is 0.5× sample frequency. The output data rate will be 7 × sample frequency as 7 data bits are output every clock cycle on each wire. Each ADC sample is sent over the 2 wires as byte-wise or bit-wise or word-wise. Submit Documentation Feedback 59 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Input Clock, CLK Freq = Fs Frame Clock, FCLK Freq = 1 ´ Fs In Byte-Wise Mode Bit Clock – SDR, DCLK Freq = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) Output Data DA1, DB1, DC1, DD1 D13 (D7) D12 (D8) D11 (D9) D10 D9 D8 D7 D13 (D7) D12 (D8) D11 (D9) D10 D9 (D10) (D11) (D12) (D13) (D10) (D11) D8 (0) D7 (0) D13 (D7) D12 (D8) D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 D0 (D10) (D12) D12 (D0) D10 (D2) (D11) (D13) D13 (D1) D11 (D3) D13 (D0) D12 (D1) D13 (D0) D12 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) (D12) Output Data DA1, DB1, DC1, DD1 D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) (D13) D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) (D12) (D13) D2 D3 D0 D1 Data Bit in MSB First Mode D3 D2 D3 D1 D1 D1 D0 D0 White Cells – Sample N D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0227-02 Figure 95. 2-Wire Interface 14× Serialization - SDR Bit Clock 60 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Input Clock, CLK Freq = Fs Frame Clock, FCLK Freq = 0.5 ´ Fs In Byte-Wise Mode Bit Clock – DDR, DCLK Freq = 3.5 ´ Fs Output Data DA0, DB0, DC0, DD0 D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) D4 (D2) D3 (D3) D2 (D4) D1 (D5) D0 (D6) D6 (D0) D5 (D1) Output Data DA1, DB1, DC1, DD1 D13 (D7) D12 (D8) D11 (D9) D10 D9 D8 (0) D7 (0) D13 (D7) D12 (D8) D11 (D9) D10 D9 (D10) (D11) (D10) (D11) D8 (0) D7 (0) D13 (D7) D12 (D8) D2 D0 (0) D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) D2 D0 (D10) (D12) D12 (D0) D10 (D2) (D11) (D13) D13 (D1) D11 (D3) 0 (D0) 0 (D1) D13 (D0) D12 (D1) In Word-Wise Mode In Bit-Wise Mode Data Rate = 7 ´ Fs Output Data DA0, DB0, DC0, DD0 D12 (D0) D10 (D2) D8 (D4) D6 (D6) D4 (D8) (D10) Output Data DA1, DB1, DC1, DD1 D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) (D11) D1 (0) D13 (D1) D11 (D3) D9 (D5) D7 (D7) D5 (D9) Output Data DA0, DB0, DC0, DD0 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) D3 D2 (D10) (D11) (D12) (D13) Output Data DA1, DB1, DC1, DD1 D13 (D0) D12 (D1) D11 (D2) D10 (D3) D9 (D4) D8 (D5) D7 (D6) D6 (D7) D5 (D8) D4 (D9) (D10) (D11) (D12) (D13) D3 Data Bit in MSB First Mode D3 D2 D3 D1 D1 D1 D0 D0 White Cells – Sample N D6 (D0) Data Bit in LSB First Mode Grey Cells – Sample N + 1 T0228-02 Figure 96. 2-Wire interface 14× Serialization - DDR Bit Clock Submit Documentation Feedback 61 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 7 LSB bits D6 - D0 and wires DA1, DB1, DC1 and DD1 carry the 7 MSB bits. Bit-wise: Each 14-bit sample is split across the 2 wires. Wires DA0, DB0, DC0 and DD0 carry the 7 even bits (D0,D2,D4..) and wires DA1, DB1, DC1 and DD1 carry the 7 odd bits (D1,D3,D5...). Word-wise: In this case, all 14-bits of a sample are sent over a single wire. Successive samples are sent over the 2 wires. For example sample N is sent on wires DA0, 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 (D13, D12, D11,...D1,D0). The data can be output LSB first also by programming the register bit <MSB_LSB_First>. 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 <DF>. In the event of an input voltage overdrive, the digital outputs go to the appropriate full-scale level. For a positive overdrive, the output code is 0x3FFF in offset binary output format, and 0x1FFF in 2s complement output format. For a negative input overdrive, the output code is 0x0000 in offset binary output format and 0x2000 in 2s complement output format. LVDS CURRENT CONTROL The default LVDS buffer current is 3.5 mA. With an external 100-Ω termination resistance, this develops ±350-mV 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 <LVDS CURR>. In addition, there exists a current double mode, where the LVDS nominal current is doubled (register bits <CURR DOUBLE>, 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 <TERM CLK> and <TERM DATA>, 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 97 and Figure 98 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 <CURR DOUBLE>, refer to Table 19). 62 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 C001 Figure 97. LVDS Data Eye Diagram with 5-pF Load Capacitance (No Internal Termination) C002 Figure 98. LVDS Data Eye Diagram with 10-pF Load Capacitance (100 Ω Internal Termination) Submit Documentation Feedback 63 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 CAPTURE TEST PATTERNS ADS644X outputs the bit clock (DCLK), positioned nearly at the center of the data transitions. It is recommended to route the bit clock, frame clock and output data lines with minimum relative skew on the PCB. This ensures sufficient setup/hold times for a reliable capture by the receiver. The DESKEW is a 1010... or 0101... pattern output on the serial data lines that can be used to verify if the receiver capture clock edge is positioned correctly. This may be useful in case there is some skew between DCLK and serial data inside the receiver. Once deserialized, it is required to ensure that the parallel data is aligned to the frame boundary. The SYNC test pattern can be used for this. For example, in the 1-wire interface, the SYNC pattern is 7 '1's followed by 7 '0's (from MSB to LSB). This information can be used by the receiver logic to shift the deserialized data till it matches the SYNC pattern. In addition to DESKEW and SYNC, the ADS644X 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 - <D13-D0> alternates between 10101010101010 and 01010101010101 every clock cycle. Custom Outputs a 14-bit custom pattern. The 14-bit custom pattern can be specified into two serial interface registers. In the 2-wire interface, each code is sent over the 2 wires depending on the serialization and bit order. Sync Deskew Outputs a sync pattern. Outputs deskew pattern. Either <D13-D0> = 10101010101010 or <D11-D0> = 01010101010101 every clock cycle. Table 26. SYNC Pattern INTERFACE OPTION 1-Wire 2-Wire 64 SERIALIZATION SYNC PATTERN ON EACH WIRE 14 X MSB-11111110000000-LSB 16 X MSB-111111111000000000-LSB 14 X MSB-1111000-LSB 16 X MSB-11110000-LSB Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 for Different Interface Options INTERFACE SERIALIZATION CLOCK PROPAGATION DELAY, tpd_clk 14x tpd_clk = 0.428xTs + tdelay 16x tpd_clk = 0.375xTs + tdelay 1-Wire with DDR bit clock 2-Wire with DDR bit clock 1 (when tpd_clk < Ts) 0 1 (when tpd_clk ≥ Ts) tpd_clk = 0.75xTs + tdelay 2-Wire with SDR bit clock (1) 2 (when tpd_clk ≥ Ts) tpd_clk = 0.428xTs + tdelay 16x (1) 0 tpd_clk = 0.857xTs + tdelay 14x 2-Wire with SDR bit clock 2-Wire with DDR bit clock SERIALIZER LATENCY clock cycles 0 (when tpd_clk < Ts) tpd_clk = 0.375xTs + tdelay 0 Note that the total latency = ADC latency + internal serializer latency. The ADC latency is 12 clock cycles. Table 28. Timings for 1-Wire Interface SERIALIZATION 14× DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 65 0.3 0.5 0.4 0.6 40 0.65 0.85 0.7 0.9 20 1.3 1.65 1.6 1.9 10 3.2 3.5 3.2 3.6 65 0.22 0.42 0.35 0.55 MAX tdelay ns MAX MIN TYP MAX Fs ≥ 40 MSPS 3 4 5 Fs < 40 MSPS 3 4.5 6 Fs ≥ 40 MSPS 3 16× 4 5 Fs < 40 MSPS 3 4.5 6 Table 29. Timings for 2-Wire Interface, DDR Bit Clock SERIALIZATION 14× 16× DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 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 1.9 105 0.35 0.55 0.4 0.6 92 0.45 0.65 0.5 0.7 80 0.55 0.75 0.6 0.8 65 0.6 0.9 0.7 1 40 1.1 1.4 1.3 1.7 MAX Submit Documentation Feedback 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 4.4 5.4 Fs < 45 MSPS 3.7 5.2 6.7 65 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 Table 30. Timings for 2-Wire Interface, SDR Bit Clock SERIALIZATION 14× 16× DATA SETUP TIME, tsu ns DATA HOLD TIME, th ns SAMPLING FREQUENCY MSPS MIN TYP MIN TYP 65 0.8 1 1 1.2 40 1.5 1.7 1.6 1.8 20 3.4 3.6 3.3 3.5 10 6.9 7.2 6.6 6.9 65 0.65 0.85 0.8 1.0 40 1.3 1.5 1.4 1.6 20 2.8 3.0 2.8 3.0 10 6.0 6.3 5.8 6.1 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 ≥ 65 66 BIT CLOCK JITTER, CYCLE-CYCLE ps, peak-peak MIN TYP MAX 350 Submit Documentation Feedback FRAME CLOCK JITTER, CYCLE-CYCLE ps, peak-peak MIN TYP 75 MAX ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 board layout schemes. 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). Submit Documentation Feedback 67 ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 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 full-scale range. Signal-to-Noise and Distortion (SINAD) – SINAD is the ratio of the power of the fundamental (PS) to the power of all the other spectral components including noise (PN) and distortion (PD), but excluding dc. 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 full-scale range. Effective Number of Bits (ENOB) – The ENOB is a measure of a converter’s performance as compared to the theoretical limit based on quantization noise. ENOB + SINAD * 1.76 6.02 (5) Total Harmonic Distortion (THD) – THD is the ratio of the power of the fundamental (PS) to the power of the first nine harmonics (PD). 68 Submit Documentation Feedback ADS6445, ADS6444 ADS6443, ADS6442 www.ti.com SLAS531 – MAY 2007 THD + 10Log10 PS 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 ∆Vsup is the change in supply voltage and ∆Vout 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 variation in the analog input common-mode by the ADC. If ∆Vcm_in is the change in the common-mode voltage of the input pins and ∆Vout is the resultant change of the ADC output code (referred to the input), then CMRR + 20Log10 DVout , expressed in dBc DVcm_in (8) Cross-Talk (only for multi-channel ADC)– This is a measure of the internal coupling of a signal from adjacent channel into the channel of interest. It is specified separately for coupling from the immediate neighbouring channel (near-channel) and for coupling from channel across the package (far-channel). It is usually measured by applying a full-scale signal in the adjacent channel. Cross-talk is the ratio of the power of the coupling signal (as measured at the output of the channel of interest) to the power of the signal applied at the adjacent channel input. It is typically expressed in dBc. Submit Documentation Feedback 69 PACKAGE OPTION ADDENDUM www.ti.com 4-Jun-2007 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty ADS6442IRGCR ACTIVE QFN RGC 64 2000 Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) ADS6442IRGCT ACTIVE QFN RGC 64 250 ADS6443IRGCR ACTIVE QFN RGC 64 2000 Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) ADS6443IRGCT ACTIVE QFN RGC 64 250 ADS6444IRGCR ACTIVE QFN RGC 64 2500 Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) ADS6444IRGCT ACTIVE QFN RGC 64 250 ADS6445IRGCR ACTIVE QFN RGC 64 2000 Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) ADS6445IRGCT ACTIVE QFN RGC 64 250 Lead/Ball Finish MSL Peak Temp (3) Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) Green (RoHS & 4204878-0001 Level-3-260C-168 HR no Sb/Br) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 30-May-2007 TAPE AND REEL INFORMATION Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com Device 30-May-2007 Package Pins Site Reel Diameter (mm) Reel Width (mm) A0 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant ADS6442IRGCR RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6442IRGCT RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6443IRGCR RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6443IRGCT RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6444IRGCR RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6444IRGCT RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6445IRGCR RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 ADS6445IRGCT RGC 64 TAI 330 16 9.3 9.3 1.5 12 16 Q2 TAPE AND REEL BOX INFORMATION Device Package Pins Site Length (mm) Width (mm) Height (mm) ADS6442IRGCR RGC 64 TAI 342.9 336.6 28.58 ADS6442IRGCT RGC 64 TAI 342.9 336.6 28.58 ADS6443IRGCR RGC 64 TAI 342.9 336.6 28.58 ADS6443IRGCT RGC 64 TAI 342.9 336.6 28.58 ADS6444IRGCR RGC 64 TAI 342.9 336.6 28.58 ADS6444IRGCT RGC 64 TAI 342.9 336.6 28.58 ADS6445IRGCR RGC 64 TAI 342.9 336.6 28.58 ADS6445IRGCT RGC 64 TAI 342.9 336.6 28.58 Pack Materials-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 30-May-2007 Pack Materials-Page 3 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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