CLC5957 12-bit, 70MSPS Broadband Monolithic A/D Converter October 1999 N CLC5957 12-bit, 70MSPS Broadband Monolithic A/D Converter General Description Features The CLC5957 is a monolithic 12-bit, 70MSPS analog-to-digital converter. The device has been optimized for use in IF-sampled digital receivers and other applications where high resolution, high sampling rate, wide dynamic range, low power dissipation, and compact size are required. The CLC5957 features differential analog inputs, low jitter differential universal clock inputs, a low distortion track-and-hold with 0-300MHz input bandwidth, a bandgap voltage reference, data valid clock output, TTL compatible CMOS (3.3V or 2.5V) programmable output logic, and a proprietary 12-bit multi-stage quantizer. The CLC5957 is fabricated on the ABIC-V 0.8 micron BiCMOS process. • 70MSPS • Wide dynamic range SFDR: 74dBc SFDR w/dither: 85dBFS SNR: 67dB • IF sampling capability • Input bandwidth = 0-300MHz • Low power dissipation: 640mW • Very small package: 48-pin TSSOP • Single +5V supply • Data valid clock output • Programmable output levels: 3.3V or 2.5V The CLC5957 features a 74dBc spurious free dynamic range (SFDR) and a 67dB signal to noise ratio (SNR). The wideband track-and-hold allows sampling of IF signals to greater than 250MHz. The part produces two-tone, dithered, SFDR of 83dBFS at 75MHz input frequency. The differential analog input provides excellent common mode rejection, while the differential universal clock inputs minimize jitter. The 48-pin TSSOP package provides an extremely small footprint for applications where space is a critical consideration. The CLC5957 operates from a single +5V power supply. Operation over the industrial temperature range of -40°C to +85°C is guaranteed. National Semiconductor tests each part to verify compliance with the guaranteed specifications. Applications • • • • • • • • Cellular base-stations Digital communications Infrared/CCD imaging IF sampling Electro-optics Instrumentation Medical imaging High definition video Actual Size ME79TG CLC5957 CL5956 IMTD N MTD ADC Block Diagram First IF Receiver DAV Clock In IF Input AIn 3-bit Q T/H 3-bit Q 3-bit Q 3-bit Q CLC5902 DVGA (∆G = 42dB) IF Saw CLC5957 12-bit 70MSPS ADC ~ ~ BPF (150MHz typ.) Noise BPF 12 Dig. Tuner/ Filter AGC 20 DAV 3-bit (Gain Control) 3 3 3 3 12 Bit Align/Error Correct Decimation/filter = 190/0.8 Output BW = 50M/190 X 0.8 = 210KHz ADC Out Receiver SINAD vs. Input Amplitude Single Tone Output Spectrum w/Dither 90 0 Output Level (dBFS) -10 SINAD dBc (BW = 216KHz) Fin = 25.3MHZ Fsample = 66MHz -20 -30 -40 -50 -60 -70 -80 -90 -100 60 50 40 30 20 10 0 0 4 8 12 16 20 24 Frequency (MHz) © 1999 National Semiconductor Corporation Printed in the U.S.A. 80 70 28 32 -125 -100 -75 -50 -25 0 Input (dBFS) http://www.national.com CLC5957 Electrical Characteristics (Vcc= +5V, 66MSPS; unless specified) (Tmin = -40°C, Tmax = +85°C) PARAMETERS RESOLUTION DIFF. INPUT VOLTAGE RANGE MAXIMUM CONVERSION RATE SNR SFDR NO MISSING CODES CONDITIONS TEMP fin = 25MHz, Ain = -1dBFS fin = 25MHz, Ain = -1dBFS fin = 5MHz, Ain = -1dBFS DYNAMIC PERFORMANCE large-signal bandwidth overvoltage recovery time effective aperture delay (Ta) aperture jitter Ain = -3dBFS Ain = 1.5FS (0.01%) Bits V MSPS dBFS dBc 300 12 -0.41 0.3 MHz ns ns ps(rms) 67 66 65 66 66 dBFS dBFS dBFS dBFS dBFS 74 74 72 69 65 dBc dBc dBc dBc dBc +25°C +25°C 68 58 dBFS dBFS +25°C 85 dBFS +25°C 83 dBFS Full Full Full Full Full Full ±0.65 ±1.5 Guaranteed 0 1.2 2.37 LSB LSB 60 60 -30 2.2 Full Full Full Full ENCODE INPUTS (Universal) VIH VIL differential input swing logic LOW logic HIGH logic HIGH TIMING (C load < 7pF) maximum conversion rate minimum conversion rate pulse width high pulse width low pipeline latency falling ENCODE to output change (50%) (Tod) rising ENCODE to DAV change (50%) (Tdv) http://www.national.com 70 63 66 12 2.048 75 66 74 Guaranteed Full Full Full +25°C +25°C +25°C Full Full Full Full Full ANALOG INPUTS analog differential input voltage range analog input resistance (single ended) analog input resistance (differential) analog input capacitance (single-ended) DIGITAL OUTPUTS output voltage OUTLEV = 1 (open) OUTLEV = 0 (GND) TYP Full Full Full Full Full fin = 5MHz, Ain = -1dBFS fin = 5MHz, Ain = -1dBFS fin = 5MHz, Ain = -1dBFS MAX 30 2.6 2.048 500 1000 2 +25°C +25°C +25°C 0 0.2 +25°C +25°C +25°C 3.2 2.4 Full +25°C Full Full Full +25°C +25°C 2 UNITS MIN +25°C +25°C +25°C +25°C NOISE AND DISTORTION signal-to-noise ratio (w/o 50 harmonics) fin = 5.0MHz Ain = -1dBFS Ain = -1dBFS fin = 25MHz fin = 75MHz Ain = -3dBFS fin = 150MHz Ain = -15dBFS fin = 250MHz Ain = -15dBFS spurious-free dynamic range Ain = -1dBFS fin = 5.0MHz fin = 25MHz Ain = -1dBFS Ain = -3dBFS fin = 75MHz fin = 150MHz Ain = -15dBFS Ain = -15dBFS fin = 250MHz intermodulation distortion fin1 = 149.84MHz, fin2 = 149.7MHz Ain = -10dBFS fin1 = 249.86MHz, fin2 = 249.69MHz Ain = -10dBFS dithered performance spurious-free dynamic range Ain = -6dBFS fin = 19MHz intermodulation distortion fin1 = 74MHz, fin2 = 75MHz Ain = -12dBFS DC ACCURACY AND PERFORMANCE differential non-linearity integral non-linearity no missing codes offset error gain error Vref RATINGS 70 0.01 3.5 2.7 2 mV %FS V 1 1 1 1 1 1 1 1 1 1 Vpp Ω Ω pF 5 V V V 3 3 3 0.4 3.8 3.0 V V V 1 1 1 MSPS MSPS ns ns clk cycle ns ns 1 75 10 7.2 7.2 3.0 10 9.6 NOTES CLC5957 Electrical Characteristics (Vcc= +5V, 66MSPS; unless specified) (Tmin = -40°C, Tmax = +85°C) PARAMETERS CONDITIONS TEMP RATINGS MIN POWER REQUIREMENTS +5V supply current Power dissipation VCC power supply rejection ratio Full Full +25°C UNITS TYP MAX 128 640 64 150 750 NOTES 2 mA mW dB 1 1 Min/max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Outgoing quality levels are determined from tested parameters. Notes 1) These parameters are 100% tested at 25°C. Sample tested at full temperature range. 3) See page 7, Figure 3 for ENCODE Inputs circuit. 2) Typical specifications are based on the mean test values of deliverable converters from the first three diffusion lots. Absolute Maximum Ratings positive supply voltage (Vcc) differential voltage between any two grounds analog input voltage range digital input voltage range output short circuit duration (one-pin to ground) junction temperature storage temperature range lead solder duration (+300°C) Recommended Operating Conditions -0.5V to +6V <100mV GND to Vcc -0.5V to +Vcc infinite 175°C -65°C to 150°C 10sec positive supply voltage (Vcc) analog input voltage range operating temperature range +5V ±5% 2.048Vpp diff. -40°C to +85°C Package Thermal Resistance Note: Absolute maximum ratings are limiting values, to be applied individually, and beyond which the serviceability of the circuit may be impaired. Functional operability under any of these conditions is not necessarily implied. Exposure to maximum ratings for extended periods may affect device reliability. Package θJA θJC 48-pin TSSOP 56°C/W 16°C/W Reliability Information Transistor count 5000 Ordering Information Model Temperature Range CLC5957MTD CLC5957PCASM Description -40°C to +85°C 48-pin TSSOP Fully loaded evaluation board with CLC5957 … ready for test. N+1 N+2 N ANALOG INPUT Ta = -410ps ENCODE CLOCK N N+1 N+2 Tdv = 9.6ns DAV CLOCK Tod = 10ns DATA OUTPUT N-3 N-2 N-1 CLC5957 Timing Diagram 3 http://www.national.com CLC5957 Typical Performance Characteristics (Vcc = +5V) SNR and SFDR vs. Input Frequency SNR and SFDR vs. Input Frequency 85 SNR (dBFS) and SFDR (dBc) SNR (dBFS) and SFDR (dBc) 85 80 75 70 SFDR 65 SNR 60 55 50 Fs = 66MSPS Ain = -3dBFS 45 40 80 75 70 SFDR 65 SNR 60 55 50 Fs = 52MSPS Ain = -3dBFS 45 40 0 100 300 200 0 100 Input Frequency (MHz) SNR and SFDR vs. Input Frequency SNR and SFDR vs. Sample Rate 90 SNR (dBc) and SFDR (dBc) SNR (dBFS) and SFDR (dBc) 85 80 75 70 SFDR SNR 65 60 55 50 Fs = 40.96MSPS Ain = -3dBFS 45 40 Fin = 24.5MHz 85 SFDR 80 75 70 SNR 65 60 55 50 0 100 40 300 200 50 Single Tone Output Spectrum 70 80 Single Tone Output Spectrum (w/Dither) 0 0 Fs = 66MSPS Ain = -1dBFS Fin = 24.5MHz -20 -30 -40 -50 -60 -70 -80 -20 -30 -40 -50 -60 -80 -90 -100 -100 5 10 15 20 25 30 Dither Signal = 500kHz @ - 28dBFS -70 -90 0 Fs = 66MSPS Ain = - 6dBFS Fin = 24.5MHz -10 Output Level (dBFS) -10 Output Level (dBFS) 60 Sample Rate (MSPS) Input Frequency (MHz) 35 0 Frequency (MHz) 5 10 15 20 25 30 35 Frequency (MHz) Differential Non-Linearity Integral Non-Linearity 1.0 2.0 Fs = 66MSPS Fin = 5MHz Fs = 66MSPS Fin = 5MHz 1.5 0.5 1.0 INL (LSBs) DNL (LSBs) 300 200 Input Frequency (MHz) 0 -0.5 0.5 0 -0.5 -1.0 -1.5 -1.0 -2.0 0 512 1024 1536 2048 2560 3072 3584 4096 0 Output Code http://www.national.com 512 1024 1536 2048 2560 3072 3584 4096 Output Code 4 SNR and SFDR vs. Input Amplitude (w/o Dither) SNR (dBc), SFDR (dBc), & THD (dBFS) SNR (dBc), SFDR (dBc), & THD (dBFS) CLC5957 Typical Performance Characteristics (Vcc = +5V) 90 80 THD 70 60 50 SFDR 40 30 SNR Fin = 20MHz Fs = 66MSPS 20 10 -50 -40 -30 -20 SNR and SFDR vs. Input Amplitude (w/Dither) 90 THD 80 70 60 50 Fin = 20MHz Fs = 66MSPS 20 10 -50 -40 SNR (dBc), SFDR (dBc), & THD (dBFS) SNR (dBc), SFDR (dBc), & THD (dBFS) SNR and SFDR vs. Input Amplitude (w/o Dither) 90 80 THD 70 SNR 50 SFDR 40 30 Fin = 75MHz Fs = 66MSPS 20 10 -50 -40 -30 -20 0 -10 80 THD 60 50 SFDR SNR 40 30 Fin = 150MHz Fs = 66MSPS 20 10 -50 -40 -30 -20 -10 0 Input Amplitude (dBFS) Two Tone Output Spectrum (w/Dither) 90 0 80 -10 THD Output Level (dBFS) SNR (dBc), SFDR (dBc), & THD (dBFS) 0 70 70 SFDR 60 SNR 40 30 Fin = 250MHz Fs = 66MSPS Fs = 66MSPS F1 = 74.5MHz F2 = 75.5MHz -20 -30 -40 -50 -60 Dither Signal = 300KHz @ -28dBFS -70 -80 -90 10 -100 -50 -40 -30 -20 0 -10 0 5 Input Amplitude (dBFS) 10 15 20 25 30 Frequency (MHz) Two Tone Output Spectrum (w/Dither) Two Tone Output Spectrum (w/Dither) 0 0 Fs = 66MSPS F1 = 149.5MHz F2 = 150.5MHz -20 -30 -40 -50 -60 Dither Signal = 300KHz @ -28dBFS -70 -80 -20 -30 -40 -50 -60 -80 -90 -100 -100 5 10 15 20 25 Dither Signal = 500KHz @ -28dBFS -70 -90 0 Fs = 66MSPS F1 = 249.5MHz F2 = 251.5MHz -10 Output Level (dBFS) -10 Output Level (dBFS) -10 90 SNR and SFDR vs. Input Amplitude (w/o Dither) 20 -20 SNR and SFDR vs. Input Amplitude (w/o Dither) Input Amplitude (dBFS) 50 -30 Input Amplitude (dBFS) Input Amplitude (dBFS) 60 SNR 30 0 -10 SFDR 40 0 30 Frequency (MHz) 5 10 15 20 25 30 Frequency (MHz) 5 http://www.national.com Physical Dimensions Symbol Min Max A – 1.10 A1 0.05 0.15 A2 0.80 1.05 b 0.17 0.27 b1 0.17 0.23 c 0.09 0.20 c1 0.09 0.16 D 12.40 12.60 E E1 e L L1 R1 Notes 2 8.1 BSC 6.00 6.20 2 0.50 BSC 0.50 0.75 1.00 REF 0.127 Notes: 1. All dimensions are in millimeters. 2. Dimensions D and E1 do not include mold protrusion. Allowable protrusion is 0.20mm per side. CLC5957 Pin Definitions GND 1 48 GND GND 2 47 GND GND 3 46 +DVCC GND 4 45 D11 (MSB) +AVCC 5 44 D10 +AVCC 6 43 D9 +AVCC 7 42 D8 GND 8 41 D7 ENCODE 9 40 D6 ENCODE 10 39 D5 GND 11 38 +DVCC GND 12 37 +DVCC AIN 13 36 GND AIN 14 35 GND GND 15 34 D4 +AVCC 16 33 D3 +AVCC 17 32 D2 +AVCC 18 31 D1 GND 19 30 D0 (LSB) GND 20 29 GND VCM 21 28 OUTLEV +AVCC 22 27 DAV GND 23 26 GND GND 24 25 GND http://www.national.com CLC5957 AIN, AIN (Pin 13, 14) Differential input with a common mode voltage of +2.4V. The ADC full scale input is 1.024Vpp on each of the complimentary input signals. ENCODE, ENCODE (Pin 9, 10) Differential clock where ENCODE initiates a new data conversion cycle on each rising edge. Logic for these inputs are 50% duty cycle universal differential signal (>200mV). The clock input is internally biased to VCC/2 with a termination impedance of 2.5kΩ. D0-D11 (Pins 30-34, 39-45) Digital data outputs are CMOS and TTL compatible. D0 is the LSB and D11 is the MSB. MSB is inverted. Output coding is two’s complement. DAV (Pin 27) Data Valid Clock. Data is valid on rising edge. OUTLEV (Pin 28) Output Logic 3.3V or 2.5V option. Open = 3.3V, GND = 2.5V. VCM (Pin 21) Internal common mode voltage reference. Nominally +2.4V. Can be used for the input common mode voltage. This voltage is derived from an internal bandgap reference. GND (Pins 1-4, 8, 11, 12, 15, 19, 20, 23-26, 29, 35, 36, 47, 48) circuit ground. +AVCC (Pins 5-7, 16-18, 22,) +5V power supply for the analog section. Bypass to ground with a 0.1µF capacitor. +DVCC (Pin 37, 38, 46) +5V power supply for the digital section. Bypass to ground with a 0.1µF capacitor. 6 CLC5957 Applications Analog Inputs and Bias Figure 1 depicts the analog input and bias scheme. Each of the differential analog inputs are internally biased to a nominal voltage of 2.40 volts DC through a 500Ω resistor to a low impedance buffer. This enables a simple interface to a broadband RF transformer with a centertapped output winding that is decoupled to the analog ground. If the application requires the inputs to be DC coupled, the Vcm output can be used to establish the proper common -mode input voltage for the ADC. The Vcm voltage reference is generated from an internal bandgap source that is very accurate and stable. ENCODE Clock Inputs The CLC5957’s differential input clock scheme is compatible with all commonly used clock sources. Although small differential and single-ended signals are adequate, for best aperture jitter performance a low noise differential clock with a high slew rate is preferred. As depicted in Figure 3, both ENCODE clock inputs are internally biased to VCC/2 though a pair of 5KΩ resistors. The clock input buffer operates with any common-mode voltage between the supply and ground. VCCA ADC Bias Mirror Ain 5kΩ 5kΩ 5kΩ To T/H and ADC 500µΑ Ain 500Ω ENC 500Ω + 1.23V Bandgap Reference 5kΩ ENC 2KΩ 2.4V – Vcm BJT Current Mirror GNDA Figure 1: CLC5957 Bias Scheme The Vcm output may also be used to power down the ADC. When the Vcm pin is pulled above 3.5V, the internal bias mirror is disabled and the total current is reduced to less than 10mA. Figure 2 depicts how this function can be used. The diode is necessary to prevent the logic gate from altering the ADC bias value. Figure 3: CLC5957 ENCODE Clock Inputs The internal bias resistors simplify the clock interface to another center-tapped transformer as depicted in Figure 4. A low phase noise, RF synthesizer of moderate amplitude (1 - 4Vpp) can drive the ADC through this interface. ENC ~ ENC CLC5957 CLC5957 5V CMOS "1" = on "0" = off Vref Figure 4: Transfer Coupled Clock Scheme Figure 2: Power Shutdown Scheme 7 http://www.national.com Figures 5 and 6 show the clock interface schemes to several other types of clock sources. VCCD 2.4Vref ENC + - CML to CMOS Digital Signal ENC Controlled Current Output Buffer + - 50Ω Digital Output 0.01µF CLC5957 10kΩ Output Level GNDD Open = 3.3Vhi GND = 2.5Vhi Figure 7: CLC5957 Digital Outputs The logic high level is slaved to the internal 2.4 voltage reference. The OUTLEV control pin selects either a 3.3V or 2.5V logic high level. An internal pullup resistor selects the 3.3 volt level as the default when the OUTLEV pin is left open. Grounding the OUTLEV pin selects the 2.5V logic high level. Figure 5: 5V CMOS Level Clock Scheme ENC ENC To ease user interface to subsequent digital circuitry, the CLC5957 has a data valid clock output (DAV). In order to match delays over IC processing variables, this digital output also uses the same output buffer as the data bits. The DAV clock output is simply a delayed version of the ENCODE input clock. Since the ADC output data change is slaved to the falling edge of the ENCODE clock, the rising DAV clock edge occurs near the center of the data valid window (or eye) regardless of the sampling frequency. CLC5957 0.01µF Figure 6: TTL or 3V CMOS Level Clock Scheme Digital Outputs and Level Select Figure 7 depicts the digital output buffer and bias used in the CLC5957. Although each of the twelve output bits uses a controlled current buffer to limit supply transients, it is recommended that parasitic loading of the outputs is minimized. Because these output transients are harmonically related to the analog input signal, excessive loading will degrade ADC performance at some frequencies. http://www.national.com 8 CLC5957 Evaluation Board Description The Evaluation board for the CLC5957 allows for easy test and evaluation of the product. The part may be ordered with all components loaded and tested. The order number is the CLC5957PCASM. The user supplies an analog input signal, encode signal and power to the board and is able to take latched 12-bit digital data out of the board. ENCODE Input (ENC) The ENCODE input is an SMA connector with a termination of 50Ω. The encode signal is converted to an AC coupled, differential clock signal centered between VCC and ground. The user should supply a sinusoidal or square wave signal of >200mVpp and <4Vpp with a 50% duty cycle. The duty cycle can vary from 50% if the minimum clock pulse width times are observed. A low jitter source will be required for IF-sampled analog input signals to maintain best performance. CLC5957 Clock Option The CLC5957 evaluation board is configured for use with an optional crystal clock oscillator source. The component Y1 may be loaded with a ”Full-sized”, HCMOS type, crystal oscillator. Analog Input (AIN) The analog input is an SMA connector with a 50Ω termination. The signal is converted from single to differential by a transformer with a 5 to 260MHz bandwidth and approximately one dB loss. Full scale is approximately 11dBm or 2.2Vpp. It is recommended that the source for the analog input signal be low jitter, low noise and low distortion to allow for proper test and evaluation of the CLC5957. Supply Voltages (J1 pins 31 A&B and 32 A&B) The CLC5957PCASM is powered from a single 5V supply connected from the referenced pins on the Eurocard connector. The recommended supplies are low noise linear supplies. Digital Outputs (J1 pins 7B (MSB, D11) through 18B (LSB) and 20B (Data Valid)) The digital outputs are provided on the Eurocard connector. The outputs are buffered by 5V CMOS latches with 50Ω series output resistors. The rising edge of Data Valid may be used to clock the output data into data collection cards or logic analyzers. The board has a location for the HP 01650-63203 termination adapter for HP 16500 logic analyzers to simplify connection to the analyzer. 9 http://www.national.com CLC5957 Evaluation Board Schematic http://www.national.com 10 CLC5957 Evaluation Board Layout CLC5957PCASM Layer 1 CLC5957PCASM Layer 2 CLC5957PCASM Layer 3 CLC5957PCASM Layer 4 11 http://www.national.com CLC5957 12-bit, 70MSPS Broadband Monolithic A/D Converter Customer Design Applications Support National Semiconductor is committed to design excellence. For sales, literature and technical support, call the National Semiconductor Customer Response Group at 1-800-272-9959 or fax 1-800-737-7018. Life Support Policy National’s products are not authorized for use as critical components in life support devices or systems without the express written approval of the president of National Semiconductor Corporation. As used herein: 1. Life support devices or systems are devices or systems which, a) are intended for surgical implant into the body, or b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. N National Semiconductor Corporation National Semiconductor Europe National Semiconductor Hong Kong Ltd. National Semiconductor Japan Ltd. 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 Fax: (+49) 0-180-530 85 86 E-mail: europe.support.nsc.com Deutsch Tel: (+49) 0-180-530 85 85 English Tel: (+49) 0-180-532 78 32 Francais Tel: (+49) 0-180-532 93 58 Italiano Tel: (+49) 0-180-534 16 80 2501 Miramar Tower 1-23 Kimberly Road Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 Tel: 81-043-299-2309 Fax: 81-043-299-2408 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. http://www.national.com 12