Data Sheet A m p l i fy t h e H u m a n E x p e r i e n c e CDK1305 10-bit, 40 MSPS 175mW A/D Converter The CDK1305 is a 10-bit, low power analog-to-digital converter capable of minimum word rates of 40 MSPS. The on-chip track-and-hold function assures very good dynamic performance without the need for external components. The input drive requirements are minimized due to the CDK1305 low input capacitance of only 5pF. Power dissipation is extremely low at only 175mW typical at 40 MSPS with a power supply of +5.0V. The digital outputs are +3V or +5V, and are user selectable. The CDK1305 is pin-compatible with an entire family of 10-bit, CMOS converters (CDK1304/05/06), which simplifies upgrades. The CDK1305 has incorporated proprietary circuit design* and CMOS processing technologies to achieve its advanced performance. Inputs and outputs are TTL/CMOS-compatible to interface with TTL/CMOS logic systems. Output data format is straight binary. Applications n All high-speed applications where low power dissipation is required n Video imaging n Medical imaging n Radar receivers n IR imaging n Digital communications The CDK1305 is available in 28-lead SOIC and 32-lead small (7mm square) TQFP packages over the commercial temperature range. Block Diagram CDK1305 10-bit, 40 MSPS 175mW A/D Converter General Description features n 40 MSPS converter n 175mW power dissipation n On-chip track-and-hold n Single +5V power supply n TTL/CMOS outputs n 5pF input capacitance n Tri-state output buffers n High ESD protection: 3,500V minimum n Selectable +3V or +5V logic I/O REV 1A Ordering Information Part Number Package Pb-Free RoHS Compliant Operating Temperature Range Packaging Method CDK1305CSO28 SOIC-28 Yes Yes 0°C to +70°C Rail CDK1305CSO28_Q SOIC-28 No No 0°C to +70°C Rail CDK1305CTQ32 TQFP-32 Yes Yes 0°C to +70°C Rail CDK1305CTQ32_Q TQFP-32 No No 0°C to +70°C Rail Moisture sensitivity level for SOIC-28 is MSL-1 and TQFP is MSL-3. ©2008 CADEKA Microcircuits LLC www.cadeka.com Data Sheet Pin Configuration SOIC-28 TQFP-32 CDK1305 10-bit, 40 MSPS 175mW A/D Converter CDK1305 CDK1305 Pin Assignments TQFP-32 Pin Name 1,8 3,4,28,29 AGND Description 2 30 VRHF Reference High Force 3 31 VRHS Reference High Sense 5 32 VRLS Reference Low Sense 6 1 VRLF Reference Low Force 9 5 VCAL Calibration Reference Analog Input Analog Ground 7 2 VIN 10 6,7 AVDD Analog VDD 11 8,9 DVDD Digital VDD 12 10,11 DGND Digital Ground 13 12 CLK Input Clock ƒCLK = FS (TTL) 15 14 EN Output Enable 16-20, 23-27 15-19, 22-26 D0-D9 28 27 D10 Tri-State Output Overrange 14 13 DAV Data Valid Output 22 21 OVDD Digital Output Supply 21 20 OGND Digital Output Ground 4 – N/C ©2008 CADEKA Microcircuits LLC REV 1A SOIC-28 Tri-State Data Output, (D0 = LSB) No Connect www.cadeka.com 2 Data Sheet Absolute Maximum Ratings The safety of the device is not guaranteed when it is operated above the “Absolute Maximum Ratings”. The device should not be operated at these “absolute” limits. Adhere to the “Recommended Operating Conditions” for proper device function. The information contained in the Electrical Characteristics tables and Typical Performance plots reflect the operating conditions noted on the tables and plots. Supply Voltages AVDD DVDD Input Voltages Analog input VRef CLK input AVDD – DVDD AGND – DGND Digital Outputs Min -0.5 0 -100 Max Unit +6 +6 V V AVDD +0.5 AVDD VDD 100 V V V mV 100 10 mV mA -100 CDK1305 10-bit, 40 MSPS 175mW A/D Converter Parameter Reliability Information Parameter Min Storage Temperature Range -65 Typ Max Unit +150 °C Max Unit +70 +175 +300 °C °C °C Recommended Operating Conditions Parameter Operating Temperature Range Junction Temperature Range Lead Temperature (soldering 10 seconds) Min 0 Typ REV 1A ©2008 CADEKA Microcircuits LLC www.cadeka.com 3 Data Sheet Electrical Characteristics (TA = TMin to TMax, AVDD = DVDD = OVDD = +5V, VIN = 0 to 4V, ƒclk = 40 MSPS, VRHS = 4V, VRLS = 0V; unless otherwise noted) Symbol Parameter Conditions Min Resolution Typ Max 10 Units bits DC Performance Differential Linearity Error(1) -0.5 ILE Integral Linearity Error -1.0 (1) No Missing Codes +0.5 LSB +1.0 LSB Guaranteed Analog Input Input Voltage Range(1) VRLS Input Resistance(2) Input Capacitance Input Bandwidth VRHS 50 Small Signal V kΩ 5 pF 250 MHz Gain Error ±2.0 LSB Offset Error ±2.0 LSB Reference Input Resistance(1) Bandwidth 300 Small Signal 500 600 150 Ω MHz VRLS(2) 0 2.0 V VRHS(2) 3.0 AVDD V 4.0 V Δ (VRHF – VRHS) 90 mV Δ (VRLS – VRLF) 75 mV VRHS 15 CLK Cycle VRLS 20 CLK Cycle Voltage Range VRHS – VRLS Reference Settling Time Conversion Characteristics 40 Minimum Conversion Rate(2) 2 MHz MHz Pipeline Delay (Latency)(2) 12 CLK Cycle Aperture Delay Time 4.0 ns Aperture Jitter Time 30 pspp ƒIN = 3.58MHz 8.5 Bits ƒIN = 10.3MHz 8.3 Bits Dynamic Performance ENOB SNR THD SINAD Effective Number of Bits Signal-to-Noise Ratio w/o Harmonics Total Harmonic Distortion Signal-to-Noise and Distortion ƒIN = 3.58MHz(1) 52 54 dB ƒIN = 10.3MHz (1) 51 52 dB ƒIN = 3.58MHz(1) , 9 distortion bins from 1024 pt FFT 55 61 dB ƒIN = 10.3MHz(1) , 9 distortion bins from 1024 pt FFT 52 53 dB ƒIN = 3.58MHz(1) 51 54 dB ƒIN = 10.3MHz(1) 49 52 dB Notes: 1. 100% production tested at +25°C. 2. Parameter is guaranteed (but not tested) by design and characterization data. ©2008 CADEKA Microcircuits LLC www.cadeka.com 4 REV 1A Maximum Conversion Rate(1) CDK1305 10-bit, 40 MSPS 175mW A/D Converter DLE Data Sheet Electrical Characteristics (TA = TMin to TMax, AVDD = DVDD = OVDD = +5V, VIN = 0 to 4V, ƒclk = 40 MSPS, VRHS = 4V, VRLS = 0V; unless otherwise noted) Symbol Parameter SFDR Conditions Spurious Free Dynamic Range Min ƒIN = 1MHz Typ Max Units pspp ±0.3 deg Differential Gain ±0.3 % CDK1305 10-bit, 40 MSPS 175mW A/D Converter 63 Differential Phase Digital Inputs Logic “1“ Voltage(1) 2.0 V Logic “0“ Voltage(1) Maximum Input Current Low (1) Maximum Input Current High(1) 0.8 V -10 +10 μA -10 +10 μA Input Capacitance +5 pF Digital Outputs Logic “1“ Voltage(1) IOH = 0.5mA Logic “0“ Voltage(1) IOL = 1.6mA TR Rise Time 15pF load 10 ns TF Fall Time 15pF load 10 ns 20pF load, TA = 25°C 10 ns 50pF load over temp 22 ns Output Enable to Data Output Delay 3.5 V 0.4 V Power Supply Requirements OVDD DVDD 3.0 Digital Voltage Supply (2) AVDD AIDD DIDD Digital Voltage Current(1) Power Dissipation(1) 5.0 V V 4.75 5.0 5.25 4.75 5.0 5.25 V 17 22 mA 18 23 mA 175 225 mW Notes: ©2008 CADEKA Microcircuits LLC REV 1A 1. 100% production tested at +25°C. 2. Parameter is guaranteed (but not tested) by design and characterization data. www.cadeka.com 5 Data Sheet Typical Performance Characteristics (TA = TMin to TMax, AVDD = DVDD = OVDD = +5V, VIN = 0 to 4V, ƒclk = 40 MSPS, VRHS = 4V, VRLS = 0V; unless otherwise noted) Performance vs. Sample RateSNR, THD, SINAD vs. Input Freq. 63 80 SNR, THD, SINAD (dB) Performance (dB) THD 61 60 59 58 SNR 57 SINAD 56 55 54 ƒIN = 1MHz 0 5 10 15 20 25 30 35 70 THD 60 50 40 30 SINAD 0 10 Sample Rate (MSPS) SNR 20 10 40 CDK1305 10-bit, 40 MSPS 175mW A/D Converter 62 100 1000 Input Frequency (MHz) SNR, THD vs. Input RangePower Dissipation vs. Sample Rate 220 60 THD 50 SNR 200 Total Power (mV) SNR, THD (dB) 70 40 30 20 ƒIN = 1MHz ƒS = 40 MSPS 0 1.0 1.5 VIN = 4V Sinewave 160 140 120 100 VIN = 0V 80 2.0 2.5 3.0 3.5 4.0 4.5 60 5.0 10 15 Input Range (V) 20 25 30 35 40 REV 1A 10 180 45 Sample Rate (MSPS) Spectral ResponsePerformance vs. Temperature 62 0 THD 60 -30 Performance (dB) Amplitude (dB) ƒIN = 1.035MHz ƒS = 40 MSPS -60 -90 58 ƒIN = 1MHz ƒS = 40 MSPS 56 SNR 54 SINAD 52 -120 0 1 2 3 4 5 6 7 8 Input Frequency (MHz) ©2008 CADEKA Microcircuits LLC 9 10 50 -40 -20 0 20 40 60 80 100 Temperature (°C) www.cadeka.com 6 Data Sheet Specification Definitions Integral Linearity Error (ILE) Aperture delay represents the point in time, relative to the rising edge of the CLOCK input, that the analog input is sampled. Linearity error refers to the deviation of each individual code (normalized) from a straight line drawn from –FS through +FS. The deviation is measured from the edge of each particular code to the true straight line. Aperture Jitter The variations in aperture delay for successive samples. Output Delay Differential Gain (DG) Time between the clock’s triggering edge and output data valid. A signal consisting of a sine wave superimposed on various DC levels is applied to the input. Differential gain is the maximum variation in the sampled sine wave amplitudes at these DC levels. Differential Phase (DP) A signal consisting of a sine wave superimposed on various DC levels is applied to the input. Differential phase is the maximum variation in the sampled sine wave phases at these DC levels. Overvoltage Recovery Time The time required for the ADC to recover to full accuracy after an analog input signal 125% of full scale is reduced to 50% of the full-scale value. Signal-To-Noise Ratio (SNR) The ratio of the fundamental sinusoid power to the total noise power. Harmonics are excluded. Effective Number Of Bits (ENOB) Signal-To-Noise And Distortion (SINAD) SINAD = 6.02N + 1.76, where N is equal to the effective number of bits. The ratio of the fundamental sinusoid power to the total noise and distortion power. N = SINAD – 1.76 6.02 Total Harmonic Distortion (THD) Small signal (50mV) bandwidth (3dB) of analog input stage. Differential Linearity Error (DLE) Error in the width of each code from its theoretical value. (Theoretical = VFS/2N) Spurious Free Dynamic Range (SFDR) The ratio of the fundamental sinusoidal amplitude to the single largest harmonic or spurious signal. Figure 1. Timing Diagram 1 ©2008 CADEKA Microcircuits LLC www.cadeka.com 7 REV 1A The ratio of the total power of the first 9 harmonics to the power of the measured sinusoidal signal. Input Bandwidth CDK1305 10-bit, 40 MSPS 175mW A/D Converter Aperture Delay Data Sheet Table 1. Timing Parameters Description Conversion Time Sym Min Typ Max Units tCLK ns tCLK 40 ns CLK High Duty Cycle tCH 40 50 60 % CLK Low Duty Cycle tCL 40 50 60 % CLK to Output Delay (15pF load) tOD 17 ns tS 10 ns CLK to DAV Figure 2. Timing Diagram 2 CDK1305 CDK1305 10-bit, 40 MSPS 175mW A/D Converter tC CLK Period REV 1A Figure 3. Typical Interface Circuit Diagram ©2008 CADEKA Microcircuits LLC www.cadeka.com 8 Data Sheet Typical Interface Circuit Power Supplies And Grounding Cadeka suggests that both the digital and the analog supply voltages on the CDK1305 be derived from a single analog supply as shown in Figure 2. A separate digital supply should be used for all interface circuitry. Cadeka suggests using this power supply configuration to prevent a possible latch-up condition on powerup. Operating Description The general architecture for the CMOS ADC is shown in the Block Diagram. The design contains 16 identical successive approximation ADC sections, all operating in parallel, a 16-phase clock generator, an 11-bit 16:1 digital output multiplexer, correction logic, and a voltage reference generator that provides common reference levels for each ADC section. Table 2. Clock Cycles Operation 1 Reference zero sampling 2 Auto-zero comparison 3 Auto-calibrate comparison 4 Input sample 5-15 16 11-bit SAR conversion Data transfer The 16-phase clock, which is derived from the input clock, synchronizes these events. The timing signals for adjacent ADC sections are shifted by one clock cycle so that the analog input is sampled on every cycle of the input clock by exactly one ADC section. After 16 clock periods, the timing cycle repeats. The latency from analog input sample to the corresponding digital output is 12 clock cycles. ©2008 CADEKA Microcircuits LLC n The auto-calibrate operation, which calibrates the gain of the MSB reference and the LSB reference, is also done with a closed loop system. Multiple samples of the gain error are integrated to produce a calibration voltage for each ADC section. Capacitive displacement currents, which can induce sampling error, are minimized since only one comparator samples the input during a clock cycle. n The total input capacitance is very low since sections of the converter that are not sampling the signal are isolated from the input by transmission gates. n Voltage Reference The CDK1305 requires the use of a single external voltage reference for driving the high side of the reference ladder. It must be within the range of 3V to 5V. The lower side of the ladder is typically tied to AGND (0.0V), but can be run up to 2.0V with a second reference. The analog input voltage range will track the total voltage difference measured between the ladder sense lines, VRHS and VRLS. Force and sense taps are provided to ensure accurate and stable setting of the upper and lower ladder sense line voltages across part-to-part and temperature variations. By using the configuration shown in Figure 4, offset and gain errors of less than ±2 LSB can be obtained. In cases where wider variations in offset and gain can be tolerated, VREF can be tied directly to VRHF, and AGND can be tied directly to VRLF as shown in Figure 5. Decouple force and sense lines to AGND with a 0.01μF capacitor (chip cap preferred) to minimize high-frequency noise injection. If this simplified configuration is used, the following considerations should be taken into account. The reference ladder circuit shown in Figure 5 is a simplified representation of the actual reference ladder with force and sense taps shown. Due to the actual internal structure of the ladder, the voltage drop from VRHF to VRHS is not equivalent to the voltage drop from VRLF to VRLS. www.cadeka.com 9 REV 1A The high sample rate is achieved by using multiple SAR ADC sections in parallel, each of which samples the input signal in sequence. Each ADC uses 16 clock cycles to complete a conversion. The clock cycles are allocated as shown in Table 2. The auto-zero operation is done using a closed loop system that uses multiple samples of the comparator’s response to a reference zero. n CDK1305 10-bit, 40 MSPS 175mW A/D Converter Very few external components are required to achieve the stated device performance. Figure 2 shows the typical interface requirements when using the CDK1305 in normal circuit operation. The following sections provide descriptions of the major functions and outline critical performance criteria to consider for achieving the optimal device performance. Clock Since only 16 comparators are used, a huge power savings is realized. n Data Sheet a specific case. VREF of 4.0V is applied to VRHF, and VRLF is tied to AGND. A 90mV drop is seen at VRHS (= 3.91V), and a 75mV increase is seen at VRLS (= 0.075V). Analog Input The drive requirements for the analog inputs are very minimal when compared to most other converters due to the CDK1305 extremely low input capacitance of only 5pF and very high input resistance of 50kΩ. The analog input should be protected through a series resistor and diode clamping circuit as shown in Figure 7. Figure 4. Ladder Force/Sense Circuit REV 1A Figure 6. Recommended Input Protection Circuit Calibration The CDK1305 uses an auto-calibration scheme to ensure 10-bit accuracy over time and temperature. Gain and offset errors are continually adjusted to 10-bit accuracy during device operation. This process is completely transparent to the user. Figure 5. Reference Ladder Circuit Typically, the top side voltage drop for VRHF to VRHS will equal: VRHF – VRHS = 2.25 % of (VRHF – VRLF) (typical) and the bottom side voltage drop for VRLS to VRLF will equal: VRLS – VRLF = 1.9 % of (VRHF – VRLF) (typical) Figure 5 shows an example of expected voltage drops for ©2008 CADEKA Microcircuits LLC Upon powerup, the CDK1305 begins its calibration algorithm. In order to achieve the calibration accuracy required, the offset and gain adjustment step size is a fraction of a 10-bit LSB. Since the calibration algorithm is an oversampling process, a minimum of 10,000 clock cycles are required. This results in a minimum calibration time upon powerup of 250μs (for a 40MHz clock). Once calibrated, the CDK1305 remains calibrated over time and temperature. Since the calibration cycles are initiated on the rising edge of the clock, the clock must be continuously applied for the CDK1305 to remain in calibration. www.cadeka.com CDK1305 10-bit, 40 MSPS 175mW A/D Converter VIN is the analog input. The input voltage range is from VRLS to VRHS (typically 4.0V) and will scale proportionally with respect to the voltage reference. (See Voltage Reference section.) 10 Data Sheet Digital Outputs All I/O pads are protected with an on-chip protection circuit shown in Figure 6. This circuit provides ESD robustness to 3.5kV and prevents latch-up under severe discharge conditions without degrading analog transition times. The digital outputs (D0–D10) are driven by a separate supply (OVDD) ranging from +3 V to +5 V. This feature makes it possible to drive the CDK1305 TTL/CMOS compatible outputs with the user’s logic system supply. The format of the output data (D0–D9) is straight binary. (See Table 3.) The outputs are latched on the rising edge of CLK. These outputs can be switched into a tri-state mode by bringing EN high. Table 3. Output Data Information Analog Input Overrange D10 Output Code D9-D0 +F.S. + 1/2 LSB 1 1111111111 +F.S. –1/2 LSB 0 1 1 1 1 1 1 1 1 1Ø +1/2 F.S. 0 ØØ ØØØØ ØØØØ +1/2 LSB 0 000000000Ø 0.0V 0 0000000000 (Ø indicates the flickering bit between logic 0 and 1.) Overrange Output Figure 7. On-Chip Protection Circuit Power Supply Sequencing Considerations This feature makes it possible to include the CDK1305 in higher resolution systems. Clock Input Evaluation Board The CDK1305 is driven from a single-ended TTL-input clock. Because the pipelined architecture operates on the rising edge of the clock input, the device can operate over a wide range of input clock duty cycles without degrading the dynamic performance. The TBD evaluation board is available to aid designers in demonstrating the full performance of the CDK1305. This board includes a reference circuit, clock driver circuit, output data latches, and an on-board reconstruction of the digital data. An application note describing the operation of this board, as well as information on the testing of the CDK1305, is also available. Contact the factory for price and availability. ©2008 CADEKA Microcircuits LLC www.cadeka.com 11 REV 1A All logic inputs should be held low until power to the device has settled to the specific tolerances. Avoid power decoupling networks with large time constants that could delay VDD power to the device. The Overrange Output (D10) is an indication that the analog input signal has exceeded the positive fullscale input voltage by 1 LSB. When this condition occurs, D10 will switch to logic 1. All other data outputs (D0 to D9) will remain at logic 1 as long as D10 remains at logic 1. CDK1305 10-bit, 40 MSPS 175mW A/D Converter Input Protection Data Sheet Mechanical Dimensions Inches Symbol A B C D E F G H I I H Min Millimeters Max Min 0.699 0.709 0.005 0.011 0.050 Typ 0.018 Typ 0.0077 0.0083 0.096 0.090 0.031 0.039 0.396 0.416 0.286 0.292 Max 17.75 18.01 0.13 0.28 1.27 BSC 0.46 BSC 0.20 0.21 2.29 2.44 0.79 0.99 10.06 10.57 7.26 7.42 A F B C D H G E TQFP-32 Package G H C D I J E Symbol A B C D E F G H I J K L Min Inches 0.346 0.272 0.346 0.272 0.031 0.012 0.053 0.002 0.037 0° 0.020 Max Millimeters 0.362 0.280 0.362 0.280 Typ 0.016 0.057 0.006 0.041 0.007 7° 0.030 Min Max 8.80 9.20 6.90 7.10 8.80 9.20 6.90 7.10 0.80 BSC 0.30 0.40 1.35 1.45 0.05 0.15 0.95 1.05 0.17 0° 7° 0.50 0.75 F K L For additional information regarding our products, please visit CADEKA at: cadeka.com CADEKA Headquarters Loveland, Colorado T: 970.663.5452 T: 877.663.5452 (toll free) CADEKA, the CADEKA logo design, COMLINEAR and the COMLINEAR logo design are trademarks or registered trademarks of CADEKA Microcircuits LLC. All other brand and product names may be trademarks of their respective companies. CADEKA reserves the right to make changes to any products and services herein at any time without notice. CADEKA does not assume any responsibility or liability arising out of the application or use of any product or service described herein, except as expressly agreed to in writing by CADEKA; nor does the purchase, lease, or use of a product or service from CADEKA convey a license under any patent rights, copyrights, trademark rights, or any other of the intellectual property rights of CADEKA or of third parties. Copyright ©2008 by CADEKA Microcircuits LLC. All rights reserved. A m p l i fy t h e H u m a n E x p e r i e n c e REV 1A A B CDK1305 10-bit, 40 MSPS 175mW A/D Converter SOIC-28 Package