(R) (R) ADS-949 14-Bit, 12.8MHz Sampling A/D Converters FEATURES * * * * * * * * * 14-bit resolution 12.8MHz minimum sampling rate No missing codes over full military temperature range Ideal for both time and frequency-domain applications Excellent THD (-81dB) and SNR (78dB) Edge-triggered Small, 32-pin, ceramic DDIP or SMT Low-power, 2 Watts Low cost INPUT/OUTPUT CONNECTIONS GENERAL DESCRIPTION The low-cost ADS-949 is a 14-bit, 12.8MHz sampling A/D converter. This device accurately samples full-scale input signals up to Nyquist frequencies with no missing codes. Excellent differential nonlinearity error (DNL), signal-to-noise ratio (SNR), and total harmonic distortion (THD) make the ADS-949 the ideal choice for both time-domain (CCD/FPA imaging, scanners, process control) and frequency-domain (radar, telecommunications, spectrum analysis) applications. The functionally complete ADS-949 contains a fast-settling sample/hold amplifier, a subranging A/D converter, an internal reference, timing/control logic, and error-correction circuitry. Digital input and output levels are TTL. The ADS-949 only requires the rising edge of a start convert pulse to operate. Requiring only +15V, +5V and -5V supplies, the ADS-949 typically dissipates just 2 Watts. The device is offered with a Bipolar input range of 2.5V and Unipolar range of 0 to 5 volts. Models are available for use in either commercial (0 to +70C) or military (-55 to +125C) operating temperature ranges. PIN FUNCTION PIN FUNCTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 VIN A VIN B -5V OFFSET ADJ. RANGE REF. 2.5V REF. START CONVERT EOC ENABLE BIT 14 (LSB) BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 RANGE GAIN ADJUST +5V ANALOG ANALOG GND +15V +5V DIGITAL DIGITAL GND OVERFLOW MSB BIT 1 (MSB) BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 A proprietary, auto-calibrating, error-correcting circuit allows the device to achieve specified performance over the full military temperature range. OFFSET ADJUST 4 BUFFER VIN A 1 - 9 ENABLE S/H VIN B 2 + 31 +5V ANALOG SUPPLY 30 +5V DIGITAL SUPPLY 27 V RANGE 32 -5.2V SUPPLY 3 +15V SUPPLY 28 ANALOG GROUND 29 DIGITAL GROUND 26 START CONVERT 7 EOC 8 REF DAC 5 AMP FLASH ADC 2 REGISTER GAIN ADJUST 12 BIT 12 13 BIT 11 OUTPUT REGISTER POWER AND GROUNDING 11 BIT 13 DIGITAL CORRECTION LOGIC FLASH ADC 1 REGISTER 10 BIT 14 (LSB) 2.5 V REF 6 14 BIT 10 15 BIT 9 16 BIT 8 17 BIT 7 18 BIT 6 19 BIT 5 20 BIT 4 21 BIT 3 22 BIT 2 23 BIT 1 (MSB) 24 MSB TIMING AND CONTROL LOGIC 25 OVERFLOW Figure 1. ADS-949 Functional Block Diagram DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * E-mail: sales@datel.com * Internet: www.datel.com (R) (R) ADS-949 ABSOLUTE MAXIMUM RATINGS PARAMETERS +5V Supply (Pins 27, 30) +15V Supply (Pin 28) -5V Supply (Pin 3) Digital Input (Pin 7) Analog Input (Pins 1, 2) Lead Temperature (10 seconds) PHYSICAL/ENVIRONMENTAL LIMITS UNITS 0 to +6 0 to +16 0 to -5.5V -0.3 to +VDD +0.3 5 +300 Volts Volts Volts Volts Volts C PARAMETERS MIN. TYP. MAX. UNITS 0 -55 -- -- +70 +125 C C Operating Temp. Range, Case ADS-949MC, GC ADS-949MM, GM, Thermal Impedance jc ca Storage Temperature Range Package Type Weight -- 6 -- C/Watt -- 23 -- C/Watt -65 -- +150 C 32-pin, metal-sealed, ceramic DDIP or SMT 0.46 ounces (13 grams) FUNCTIONAL SPECIFICATIONS (TA = +25C, +VDD = +5V, -VDD = -5V, +Vcc = +15V, 12.8MHz sampling rate, 2.5V input range, and a minimum 3 minute warmup unless otherwise specified.) +25C 0 to +70C -55 to +125C ANALOG INPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS Bipolar Input Voltage Range Unipolar Input Voltage Range Input Resistance (Vin A) Input Capacitance 1 0 to 2 -- -- -- -- 400 6 2.5 0 to 5 -- 15 1 0 to 2 -- -- -- -- 400 6 2.5 0 to 5 -- 15 1 0 to 2 -- -- -- -- 400 6 2.5 0 to 5 -- 15 Volts Volts pF +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- Volts Volts A A ns -- -- -0.95 -- -- -- 14 14 0.75 0.5 0.15 0.1 0.2 -- -- -- +1.25 0.4 0.3 0.4 -- -- -- -0.95 -- -- -- 14 14 0.75 0.5 0.15 0.1 0.2 -- -- -- +1.25 0.4 0.3 0.4 -- -- -- -0.95 -- -- -- 14 14 1 0.5 0.4 0.3 0.4 -- -- -- +1.5 0.8 0.6 1.5 -- Bits LSB LSB %FSR %FSR % Bits -- -- -- -83 -78 -76 -76 -72 -71 -- -- -- -83 -78 -76 -75 -72 -71 -- -- -- -79 -73 -71 -71 -68 -65 dB dB dB -- -- -- -81 -76 -74 -74 -71 -69 -- -- -- -81 -76 -74 -74 -71 -69 -- -- -- -77 -72 -69 -70 -66 -63 dB dB dB 72 72 72 78 77 76 -- -- -- 72 72 72 78 77 76 -- -- -- 70 70 70 78 77 76 -- -- -- dB dB dB 70 70 69 -- 77 74 73 150 -- -- -- -- 70 70 69 -- 74 74 73 150 -- -- -- -- 68 66 65 -- 73 71 70 150 -- -- -- -- dB dB dB Vrms -- -82 -- -- -82 -- -- -82 -- dB -- -- -- -- -- -- 30 20 85 400 +5 2 -- -- -- -- -- -- -- -- -- -- -- -- 30 20 85 400 +5 2 -- -- -- -- -- -- -- -- -- -- -- -- 30 20 85 400 +5 2 -- -- -- -- -- -- MHz MHz dB V/s ns ps rms DIGITAL INPUT Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Start Convert Positive Pulse Width STATIC PERFORMANCE Resolution Integral Nonlinearity Differential Nonlinearity (fin = 10kHz) Full Scale Absolute Accuracy Bipolar Zero Error (Tech Note 2) Gain Error (Tech Note 2) No Missing Codes (fin = 10kHz) DYNAMIC PERFORMANCE Peak Harmonics (-0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Total Harmonic Distortion (-0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Signal-to-Noise Ratio (w/o distortion, -0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Signal-to-Noise Ratio (& distortion, -0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Noise Two-tone Intermodulation Distortion (fin = 2.45MHz, 1.975MHz, fs = 10MHz, -0.5dB) Input Bandwidth (-3dB) Small Signal (-20dB input) Large Signal (-0.5dB input) Feedthrough Rejection (fin = 5MHz) Slew Rate Aperture Delay Time Aperture Uncertainty 2 (R) (R) ADS-949 +25C 0 to +70C -55 to +125C DYNAMIC PERFORMANCE (Cont.) MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS S/H Acquisition Time ( to 0.003%FSR, 5V step) Overvoltage Recovery Time A/D Conversion Rate -- -- 12.8 40 -- -- 45 100 -- -- -- 12.8 40 -- -- 45 100 -- -- -- 12.8 40 -- -- 45 100 -- ns ns MHz +2.4 -- -- -- -- -- -- -- -- +0.4 -4 +4 +2.4 -- -- -- +2.4 -- -- -- -- -- -- -- -- +0.4 -4 +4 Volts Volts mA mA +4.75 -4.75 +14.5 +5.0 -5.2 +15 +5.25 -5.45 +15.5 +4.75 -4.75 +14.5 +5.0 -5.2 +15 +5.25 -5.45 +15.5 +4.9 -4.9 +14.5 +5.0 -5.2 +15 +5.25 -5.45 +15.5 Volts Volts Volts -- -- +14.5 -- -- +250 -200 +15 2.0 -- +260 -210 +15.5 2.25 0.1 -- -- +14.5 -- -- +250 -200 +15 2.0 -- +260 -210 +15.5 2.25 0.1 -- -- +14.5 -- -- +250 -200 +15 2.0 -- +260 -210 +15.5 2.25 0.1 mA mA Volts Watts %FSR/%V DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding -- -- -- +0.4 -- -4 -- +4 Straight Binary, Offset Binary POWER REQUIREMENTS Power Supply Ranges +5V Supply -5.2V Supply +15V Supply Power Supply Currents +5V Supply -5.2V Supply +15V Supply Power Dissipation Power Supply Rejection Footnotes: Effective bits is equal to: All power supplies should be on before applying a start convert pulse. All supplies and the clock (start convert pulses) must be present during warmup periods. The device must be continuously converting during this time. (SNR + Distortion) - 1.76 + 20 log Full Scale Amplitude Actual Input Amplitude 6.02 Contact DATEL for other input voltage ranges. A 50ns wide start convert pulse is used for all production testing. For applications requiring less than an 12.8MHz sampling rate, wider start convert pulses can be used. TECHNICAL NOTES +5VA and +5VD supplies should be powered up from the same source. If required, the device's small initial offset and gain errors can be reduced to zero using the adjustment circuitry shown in Figure 2,3. 1. Obtaining fully specified performance from the ADS-949 requires careful attention to pc card layout and power supply decoupling. The device's analog and digital ground systems are connected to each other internally. For optimal performance, tie all ground pins (26 and 29) directly to a large analog ground plane beneath the package. When using this circuitry, or any similar offset and gain calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before gain. Bypass all power supplies to ground with 4.7F tantalum capacitors in parallel with 0.1F ceramic capacitors. Locate the bypass capacitors as close to the unit as possible. 3. Applying a start convert pulse while a conversion is in progress (EOC = logic 1) will initiate a new and inaccurate conversion cycle. Data for the interrupted and subsequent conversions will be invalid. 2. The ADS-949 achieves its specified accuracies without the need for external calibration. It is recommended that the 4. A passive bandpass filter is used at the input of the A/D for all production testing. 3 (R) (R) ADS-949 CALIBRATION PROCEDURE Zero/Offset Adjust Procedure Any offset and/or gain calibration procedures should not be implemented until devices are fully warmed up. To avoid interaction, offset must be adjusted before gain. The ranges of adjustment for the circuits in Figures 2 and 3 are guaranteed to compensate for the ADS-949's initial accuracy errors and may not be able to compensate for additional system errors. 1. Apply a train of pulses to the START CONVERT input (pin 7) so the converter is continuously converting. 2. Apply +153V to the ANALOG INPUT (pin 1). 3. Adjust the offset potentiometer until the output bits are 10 0000 0000 0000 and the LSB flickers between 0 and 1. A/D converters are calibrated by positioning their digital outputs exactly on the transition point between two adjacent digital output codes. This can be accomplished by connecting LED's to the digital outputs and adjusting until certain LED's "flicker" equally between on and off. Other approaches employ digital comparators or microcontrollers to detect when the outputs change from one code to the next. Gain Adjust Procedure 1. Apply +2.49954V to the ANALOG INPUT (pin 1). 2. Adjust the gain potentiometer until all output bits are 1's and the LSB flickers between 1 and 0. 3. To confirm proper operation of the device, vary the input signal to obtain the output coding listed in Table 2. Offset adjusting for the ADS-949 is normally accomplished at the point where the MSB is a 1 and all other output bits are 0's and the LSB just changes from a 0 to a 1. This digital output transition ideally occurs when the applied analog input is +1/2 LSB (+153V). Table 1. Gain and Zero Adjust Gain adjusting is accomplished when all bits are 1's and the LSB just changes from a 1 to a 0. This transition ideally occurs when the analog input is at +full scale minus 11/2 LSB's (+2.49954V). INPUT VOLTAGE RANGE 2.5V -5V +5VA ZERO ADJUST +1/2 LSB GAIN ADJUST +FS -11/2 LSB +153V +2.49954V +5VD +15V 4.7F + 4.7F + 0.1F 0.1F 4.7F + 4.7F + 0.1F 0.1F 28 30 29 +15V AGND +5VA 3 -5V 27 26 +5VD DGND 5 RANGE REF +5V 2 VIN B BIPOLAR ANALOG INPUT GAIN ADJUST 20K 1VIN A 31 GAIN ADJUST ADS-949 +5V ZERO/ OFFSET ADJUST -5V 20k 4 OFFSET ADJUST 20k9 -5V START CONVERT 32 RANGE 6 2.5V REF 7 START CONVERT 23 22 21 20 19 18 17 16 15 14 13 12 11 10 8 BIT 1 (MSB) BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT 8 BIT 9 BIT 10 BIT 11 BIT 12 BIT 13 BIT 14 (LSB) EOC 9 ENABLE Bypass Pins 5, 6, 32, with a 4.7F to Analog Ground. Note: The Voltage Value at Pin 32 (Range) sets the input voltage range of the ADS-949 eg: If Pin 6 (2.5V Reference Out) is tied to the Range Pin 32 (20k Pot is shorted), then the input range of the ADS-949 becomes 2.5V If the 20k Pot is set at midrange then the input range of the ADS-949 becomes 1.25V Figure 2. Typical ADS-949 Bipolar Connection Diagram 4 (R) (R) ADS-949 THERMAL REQUIREMENTS All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70C and -55 to +125C. All room temperature (TA = +25C) production testing is performed without the use of heat sinks or forced air cooling. Thermal impedance figures for each device are listed in their respective specification tables. Electrically-insulating, thermally-conductive "pads" may be installed underneath the package. Devices should be soldered to boards rather than socketed, and of course, minimal air flow over the surface can greatly help reduce the package temperature. In more severe ambient conditions, the package/junction temperature of a given device can be reduced dramatically (typically 35%) by using one of DATEL's HS Series heat sinks. See Ordering Information for the assigned part number. See page 1-183 of the DATEL Data Acquisition Components Catalog for more information on the HS Series. Request DATEL Application Note AN8, "Heat Sinks for DIP Data Converters", or contact DATEL directly, for additional information. These devices do not normally require heat sinks, however, standard precautionary design and layout procedures should be used to ensure devices do not overheat. The ground and power planes beneath the package, as well as all pcb signal runs to and from the device, should be as heavy as possible to help conduct heat away from the package. Table 3. Output Coding STRAIGHT BIN. UNIPOLAR SCALE INPUT VOLT. 0 TO +5V +FS - 1 LSB +7/8 FS +3/4 FS +1/2 FS +1/4 FS +1/8 FS +1 LSB 0 +4.999695 +4.375000 +3.75000 +2.500000 +1.250000 +0.625000 +0.000305 0.000000 LSB OUTPUT CODING MSB LSB 11 1111 1111 1111 11 1000 0000 0000 11 0000 0000 0000 10 0000 0000 0000 01 0000 0000 0000 00 1000 0000 0000 00 0000 0000 0001 00 0000 0000 0000 01 1111 1111 1111 01 1000 0000 0000 01 0000 0000 0000 00 0000 0000 0000 11 0000 0000 0000 10 1000 0000 0000 10 0000 0000 0001 10 0000 0000 0000 MSB OFF. BINARY INPUT VOLT. 2.5V +2.499695 +1.875000 +1.250000 0.000000 -1.250000 -1.875000 -2.499695 -2.500000 BIPOLAR SCALE +FS - 1LSB +3/4FS +1/2FS 0 -1/2FS -3/4FS -FS+1LSB -FS TWO'S COMP. -5V +5VA +5VD +15V 4.7F + 4.7F + 0.1F 0.1F UNIPOLAR ANALOG INPUT GAIN ADJUST 20K 4.7F + 0.1F 0.1F 28 30 29 +15V AGND +5VA 3 5 RANGE REF -5V 1VIN A +5V 4.7F + 27 26 +5VD DGND 2 VIN B 31 GAIN ADJUST +5V ADS-949 ZERO/ OFFSET ADJUST -5V 20k 4 OFFSET ADJUST 20k9 -5V START CONVERT 32 RANGE 6 2.5V REF 7 START CONVERT 9 ENABLE 23 22 21 20 19 18 17 16 15 14 13 12 11 10 8 Bypass Pins 5, 6, 32 with a 4.7F to Analog Ground. Note: The Voltage Value at Pin 32 (Range) sets the input voltage range of the ADS-949 eg: If Pin 6 (2.5V Reference Out) is tied to the Range Pin 32 (20k Pot is shorted), then the input range of the ADS-949 becomes 0 to 5V If the 20k Pot is set at midrange then the input range of the ADS-949 becomes 0 to 2.5V Figure 3. Typical ADS-949 Unipolar Connection Diagram 5 BIT 1 (MSB) BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT 8 BIT 9 BIT 10 BIT 11 BIT 12 BIT 13 BIT 14 (LSB) EOC (R) (R) ADS-949 Figure 5. FFT Analysis of ADS-949 Figure 6. ADS-949 Histogram (fs = 12.8MHz, fin = 3.85MHz, Vin = -0.5dB, 16,384 point FFT) N START CONVERT Minimum is 40ns N+1 40ns EOC 40ns 60ns DATA OUT DATA N-3 DATA N-2 DATA N-1 DATA N 20ns ENABLED 30ns OUTPUT DATA ENABLED DATA N-3 DATA N-2 HZ DATA N-1 HZ 20ns Note: 1. Scale is approximately 10ns per division. All values are Typical. Figure 7. ADS-949 Timing Diagram 6 DATA N HZ HZ (R) (R) 7 CONTACT DATEL FOR SCHEMATIC ADS-949 Figure 7. ADS-949 Evaluation Board Schematic (ADS-B949) (R) (R) ADS-949 MECHANICAL DIMENSIONS INCHES (mm) 1.62 MAX. (41.15) Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) 0.010 (0.254) 3 place decimal (.XXX) 0.005 (0.127) 0.92 MAX. (23.37) Lead Material: Kovar Alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 1.50 TYP (38.10) SEATING PLANE 0.05 TYP. (1.27) 0.220 TYP. (6.86) PIN 1 INDEX 0.010 TYP. (0.254) 0.05 TYP. (1.27) 0.018 TYP. (0.46) 0.100 TYP. (2.54) 0.175 TYP (4.45) 0.90 TYP. (22.86) 0.05 TYP. (1.27) ORDERING INFORMATION MODEL OPERATING TEMP. RANGE 32-PIN PACKAGE ADS-949MC ADS-949MM ADS-949/883 ADS-949GC ADS-949GM 0 to +70C -55 to +125C -55 to +125C 0 to +70C -55 to +125C DDIP DDIP DDIP SMT SMT ACCESSORIES ADS-B949 Evaluation Board (without ADS-949) Receptacles for PC board mounting can be ordered through AMP, Inc., Part # 3-331272-8 (Component Lead Socket), 32 required. For MIL-STD-883 product specifcation, contact DATEL. (R) (R) ISO 9001 R E G I S T E R E D DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com E-mail:sales@datel.com Data Sheet Fax Back: (508) 261-2857 DS-0434A 7/22/99 DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 1-34-60-01-01 DATEL GmbH Munchen, Germany Tel: 89-544334-0 DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025 DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.