ADS-937MM

® ® ADS-937 16-Bit, 1MHz, Low-Power Sampling A/D Converters FEATURES • • • • • • • • • 16-bit resolution 1MHz minimum sampling rate No missing codes over full military temperature range Very low power, 1.25 Watts Small, 32-pin, side-brazed, ceramic TDIP Edge-triggered Excellent performance Ideal for both time and frequency-domain applications Low cost INPUT/OUTPUT CONNECTIONS PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 FUNCTION ANALOG INPUT ANALOG GROUND UNIPOLAR OFFSET ADJUST +5V REFERENCE OUT GAIN ADJUST COMPENSATION –15V SUPPLY +15V SUPPLY +5V ANALOG SUPPLY –5V ANALOG SUPPLY ANALOG GROUND DIGITAL GROUND +5V DIGITAL SUPPLY EOC START CONVERT PIN 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 FUNCTION 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 BIT 15 BIT 16 (LSB) GENERAL DESCRIPTION The low-cost ADS-937 is a 16-bit, 1MHz sampling A/D converter. This device accurately samples full-scale input signals up to Nyquist frequencies with no missing codes. This feature, combined with excellent signal-to-noise ratio (SNR) and total harmonic distortion (THD), makes the ADS-937 the ideal choice for both time-domain (CCD/medical imaging, scanners, process control) and frequency-domain (radar, telecommunications, spectrum analysis) applications. Packaged in a 32-pin, side-brazed, metal-sealed, ceramic TDIP, the functionally complete ADS-937 contains a fastsettling sample-hold amplifier, a subranging (two-pass) A/D converter, an internal reference, timing/control logic, and errorcorrection circuitry. Digital input and output levels are TTL. ADS-937 only requires the rising edge of the start convert pulse to operate. Requiring ±15V and ±5V supplies, the ADS-937 typically dissipates 1.25 Watts. The device is offered with both bipolar (±5V) and unipolar (0 to –10V) analog input ranges. Models are available for use in either commercial (0 to +70°C) or military (–55 to +125°C) operating temperature ranges. A proprietary, auto-calibrating, error-correcting circuit enables the device to achieve specified performance over the full military temperature range. UNIPOLAR 3 OFFSET ADJUST 4 32 BIT 1 (MSB) BUFFER ANALOG INPUT 1 31 BIT 2 – S/H + FLASH ADC 1 D IG I TA L C O R R EC T IO N L O G I C 30 BIT 3 29 BIT 4 28 BIT 5 27 BIT 6 26 BIT 7 25 BIT 8 24 BIT 9 23 BIT 10 22 BIT 11 21 BIT 12 20 BIT 13 19 BIT 14 18 BIT 15 17 BIT 16 (LSB) GAIN ADJUST 6 GAIN CIRCUIT REF +5V REFERENCE OUT 5 COMPENSATION 7 Σ DAC AMP FLASH ADC 2 START CONVERT 16 EOC 15 TIMING AND CONTROL LOGIC 10 +5V ANALOG SUPPLY 11 –5V ANALOG SUPPLY 2, 12 ANALOG GROUND 14 +5V DIGITAL SUPPLY 9 +15V SUPPLY 8 –15V SUPPLY 13 DIGITAL GROUND Figure 1. ADS-937 Functional Block Diagram DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: (508) 339-3000, (800) 233-2765 Fax: (508) 339-6356 • Email: sales@datel.com • Internet: www.datel.com ® ® ADS-937 ABSOLUTE MAXIMUM RATINGS PARAMETERS +15V Supply (Pin 9) –15V Supply (Pin 8) +5V Supply (Pins 10, 14) –5V Supply (Pin 11) Digital Input (Pin 16) Analog Input (Pin 1) Lead Temperature (10 seconds) LIMITS 0 to +16 0 to –16 0 to +6 0 to –6 –0.3 to +VDD +0.3 ±15 +300 UNITS Volts Volts Volts Volts Volts Volts °C PHYSICAL/ENVIRONMENTAL PARAMETERS Operating Temp. Range, Case ADS-937MC ADS-937MM/883 Thermal Impedance θjc θca Storage Temperature Range Package Type Weight MIN. 0 –55 — — –65 TYP. — — 5 22 — MAX. +70 +125 — — +150 UNITS °C °C °C/Watt °C/Watt °C 32-pin,side-brazed, metal-sealed, ceramic TDIP 0.56 ounces (16 grams) FUNCTIONAL SPECIFICATIONS (TA = +25°C, ±VCC = ±15V, ±VDD = ±5V, 1MHz sampling rate, and a minimum 1 minute warm-up Œ unless otherwise specified.) +25°C ANALOG INPUTS Input Voltage Ranges  Bipolar Unipolar Input Resistance Input Capacitance DIGITAL INPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Start Convert Positive Pulse Width Ž STATIC PERFORMANCE Resolution Integral Nonlinearity Differential Nonlinearity (fin = 10kHz) Full Scale Absolute Accuracy Bipolar Zero Error (Tech Note 2) Bipolar Offset Error (Tech Note 2) Gain Error (Tech Note 2) Unipolar Offset Error (Tech Note 2) No Missing Codes (fin = 10kHz) DYNAMIC PERFORMANCE Peak Harmonics (–0.5dB) dc to 100kHz 100kHz to 500kHz Total Harmonic Distortion (–0.5dB) dc to 100kHz 100kHz to 500kHz Signal-to-Noise Ratio (w/o distortion, –0.5dB) dc to 100kHz 100kHz to 500kHz Signal-to-Noise Ratio  (& distortion, –0.5dB) dc to 100kHz 100kHz to 500kHz Noise Two-Tone Intermodulation Distortion (fin = 100kHz, 240kHz, fs = 1MHz, –0.5dB) Input Bandwidth (–3dB) Small Signal (–20dB input) Large Signal (–0.5dB input) Feedthrough Rejection (fin = 500kHz) Slew Rate Aperture Delay Time Aperture Uncertainty S/H Acquisition Time ( to ±0.003%FSR, 10V step) Overvoltage Recovery Time  A/D Conversion Rate — — — — 85 84 81 80 — — — — — — — — — — 1 –90 –88 –87 –86 88 87 85 84 110 –85 4.5 4 84 ±33 +20 5 260 500 — –84 –81 –82 –81 — — — — — — — — — — — — 300 1000 — — — — — 85 84 81 80 — — — — — — — — — — 1 –90 –88 –87 –86 88 87 85 84 110 –85 4.5 4 84 ±33 +20 5 260 500 — –84 –81 –82 –81 — — — — — — — — — — — — 300 1000 — — — — — 84 83 80 78 — — — — — — — — — — 1 –88 –87 –86 –85 87 87 84 83 110 –85 4.5 4 84 ±33 +20 5 260 500 — –83 –80 –81 –80 — — — — — — — — — — — — 300 1000 — dB dB dB dB dB dB dB dB µVrms dB MHz MHz dB V/µs ns ps rms ns ns MHz — — –0.95 — — — — — 16 16 ±0.75 ±0.5 ±0.1 ±0.1 ±0.1 ±0.1 ±0.1 — — — +1 ±0.25 ±0.15 ±0.2 ±0.3 ±0.15 — — — – 0.95 — — — — — 16 16 ±1.5 ±0.5 ±0.2 ±0.1 ±0.15 ±0.25 ±0.1 — — — +1 ±0.4 ±0.25 ±0.3 ±0.5 ±0.25 — — — –0.95 — — — — — 16 16 ±2 ±0.5 ±0.25 ±0.15 ±0.2 ±0.4 ±0.15 — — — +1.5 ±0.5 ±0.5 ±0.5 ±0.7 ±0.5 — Bits LSB LSB %FSR %FSR %FSR % %FSR Bits +2.0 — — — 20 — — — — 500 — +0.8 +20 –20 — +2.0 — — — 20 — — — — 500 — +0.8 +20 –20 — +2.0 — — — 20 — — — — 500 — +0.8 +20 –20 — Volts Volts µA µA ns MIN. — — — — TYP. ±5 0 to –10 1 7 MAX. — — — 15 MIN. — — — — 0 to +70°C TYP. ±5 0 to –10 1 7 MAX. — — — 15 MIN. — — — — –55 to +125°C TYP. ±5 0 to –10 1 7 MAX. — — — 15 UNITS Volts Volts kΩ pF 2 ® ® ADS-937 +25°C ANALOG OUTPUT Internal Reference Voltage Drift External Current DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding POWER REQUIREMENTS Power Supply Ranges +15V Supply –15V Supply +5V Supply –5V Supply Power Supply Currents +15V Supply –15V Supply +5V Supply –5V Supply Power Dissipation Power Supply Rejection +14.5 –14.5 +4.75 –4.75 — — — — — — +15.0 –15.0 +5.0 –5.0 +7 –8 +133 –72 1.25 — +15.5 –15.5 +5.25 –5.25 +9 –10 +145 –80 1.35 ±0.01 +14.5 –14.5 +4.75 –4.75 — — — — — — +2.4 — — — — — — — — +0.4 –4 +4 MIN. +4.95 — — TYP. +5.0 ±30 1 MAX. +5.05 — — MIN. +4.95 — — 0 to +70°C TYP. +5.0 ±30 1 MAX. +5.05 — — MIN. +4.95 — — –55 to +125°C TYP. +5.0 ±30 1 MAX. +5.05 — — UNITS Volts ppm/°C mA +2.4 — — +2.4 — — +0.4 — — — –4 — — — +4 — Complementary Binary / Complementary Offset Binary — — — — — +0.4 –4 +4 Volts Volts mA mA +15.0 –15.0 +5.0 –5.0 +7 –8 +133 –72 1.25 — +15.5 –15.5 +5.25 –5.25 +9 –10 +145 –80 1.35 ±0.01 +14.5 –14.5 +4.75 –4.75 — — — — — — +15.0 –15.0 +5.0 –5.0 +7 –8 +133 –72 1.25 — +15.5 –15.5 +5.25 –5.25 +9 –10 +145 –80 1.35 ±0.01 Volts Volts Volts Volts mA mA mA mA Watts %FSR/%V Footnotes: Œ All power supplies must be on before applying a start convert pulse. All supplies and the clock (START CONVERT) must be present during warm-up periods. The device must be continuously converting during this time.  Contact DATEL for other input voltage ranges. Ž A 1MHz clock with a 500nsec positive pulse width (50% duty cycle) is used for all production testing. Any duty cycle may be used as long as a minimum positive pulse width of 20nsec is maintained. For applications requiring lower sampling rates, clock frequencies less than 1MHz may be used.  Effective bits is equal to: (SNR + Distortion) – 1.76 + 20 log 6.02 Full Scale Amplitude Actual Input Amplitude  This is the time required before the A/D output data is valid once the analog input is back within the specified range. TECHNICAL NOTES 1. Obtaining fully specified performance from the ADS-937 requires careful attention to pc-card layout and power supply decoupling. The device's analog and digital ground systems are not connected to each other internally. For optimal performance, tie all ground pins (2, 12 and 13) directly to a large analog ground plane beneath the package. Bypass all power supplies and the +5V REFERENCE OUTPUT (pin 5) to ground with 4.7µF tantalum capacitors in parallel with 0.1µF ceramic capacitors. Locate the bypass capacitors as close to the unit as possible. Tie a 47µF capacitor between COMPENSATION (pin 7) and ground (See figure 2.). 2. The ADS-937 achieves its specified accuracies without the need for external calibration. If required, the device's small initial offset and gain errors can be reduced to zero using the adjustment circuitry shown in Figure 2. When using this circuitry, or any similar offset and gain calibration hardware, make adjustments following warm-up. To avoid interaction, always adjust offset before gain. Float pins 4 and 6 if not using offset and gain adjust circuits. 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. THERMAL REQUIREMENTS All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70°C and –55 to +125°C. All room-temperature (TA = +25°C) 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. 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. 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. 3 ® ® ADS-937 CALIBRATION PROCEDURE Connect the converter per Table 1 for the appropriate input voltage range. Any offset/gain calibration procedures should not be implemented until the device is fully warmed up. To avoid interaction, adjust offset before gain. The ranges of adjustment for the circuits in Figure 2 are guaranteed to compensate for the ADS-937's initial accuracy errors and may not be able to compensate for additional system errors. A/D converters are calibrated by positioning their digital outputs exactly on the transition point between two adjacent digital output codes. This is accomplished by connecting LED's to the digital outputs and performing adjustments 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. For the ADS-937, offset adjusting is normally accomplished when the analog input is 0 minus ½LSB (–76.3µV). See Table 2 for the proper bipolar and unipolar output coding. Gain adjusting is accomplished when the analog input is at nominal full scale minus 1½LSB's (–9.999771V for unipolar and –4.999771V for bipolar). Zero/Offset Adjust Procedure 1. Apply a train of pulses to the START CONVERT input (pin 16) so that the converter is continuously converting. 2. For unipolar or bipolar zero/offset adjust, apply –76.3µV to the ANALOG INPUT (pin 1). 3. For a bipolar input - Adjust the offset potentiometer until the output code flickers equally between 1000 0000 0000 0000 and 0111 1111 1111 1111. For a unipolar input - Adjust the offset potentiometer until all output bits are 0's and the LSB flickers between 0 and 1. Gain Adjust Procedure 1. Apply –4.999771V to the ANALOG INPUT (pin 1) for bipolar gain adjust or apply –9.999771V to pin 1 for unipolar gain adjust. 2. For a unipolar input - Adjust the gain potentiometer until all output bits are 1's and the LSB flickers between 1 and 0. For a bipolar input - 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 applied input voltage to obtain the output coding listed in Table 2. Table 1. Input Connections INPUT VOLTAGE RANGE ±5V 0 to –10V INPUT PIN Pin 1 Pin 1 TIE TOGETHER Pins 2 and 3 Pins 3 and 5 Table 2. Output Coding COMPLEMENTARY BINARY COMPLEMENTARY OFFSET BINARY UNIPOLAR SCALE –FS +1 LSB –7/8 FS –3/4 FS –1/2 FS –1/4 FS –1/8 FS –1 LSB 0 INPUT VOLTAGE 0 to –10V –9.999847 –8.750000 –7.500000 –5.000000 –2.500000 –1.250000 –0.000153 0.000000 OUTPUT CODING MSB LSB MSB LSB INPUT RANGE ±5V +4.999847 +3.750000 +2.500000 +0.000000 –2.500000 –3.750000 –4.999847 –5.000000 BIPOLAR SCALE +FS –1 LSB +3/4 FS +1/2 FS 0 –1/2 FS –3/4 FS –FS +1 LSB –FS 1111 1111 1111 1111 1110 0000 0000 0000 1100 0000 0000 0000 1000 0000 0000 0000 0100 0000 0000 0000 0010 0000 0000 0000 0000 0000 0000 0001 0000 0000 0000 0000 0000 0000 0000 0000 0001 1111 1111 1111 0011 1111 1111 1111 0111 1111 1111 1111 1011 1111 1111 1111 1101 1111 1111 1111 1111 1111 1111 1110 1111 1111 1111 1111 4 ® ® ADS-937 Pin 5 (ADS-937) +15V 10kΩ 6 GAIN ADJUST +5V DIGITAL 4.7µF 0.1µF 14 15 EOC 4 OFFSET ADJUST 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 7 1 3 47µF + ANALOG INPUT UNIPOLAR 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 BIT 15 BIT 16 (LSB) 20kΩ –15V 13 DIGITAL GROUND 8 –15V 4.7µF 0.1µF + 12 ANALOG GROUND 9 +15V 4.7µF 0.1µF + ADS-937 +5V ANALOG 4.7µF 10 + 0.1µF + 2 ANALOG GROUND 11 5 +5V REF. OUT 0.1µF 4.7µF START CONVERT COMPENSATION –5V ANALOG 4.7µF 0.1µF Figure 2. Typical ADS-937 Connection Diagram N START CONVERT 500ns typ. N+1 5ns typ. INTERNAL S/H 740ns typ. Hold Acquisition Time 260ns typ. 65ns typ. EOC Conversion Time 730ns typ. 20ns typ. OUTPUT DATA Data N-2 Valid Invalid Data Data N-1 Valid 980ns typ. 20ns N Scale is approximately 50ns per division. Note: Scale is approximately 50ns per division. Sampling Rate = 1MHz. Figure 3. ADS-937 Timing Diagram 5 ® ® ADS-937 ADS-937 0 –10 –20 Amplitude Relative to Full Scale (dB) –30 –40 –50 –60 –70 –80 –90 –100 –110 –120 –130 –140 –150 0 50 kHz 100 kHz 150 kHz 200 kHz 250 kHz 300 kHz 350 kHz 400 kHz 450 kHz 500 kHz Frequency (fs = 1MHz, fin = 480kHz, Vin = – 0.5dB, 16,384-point FFT) Figure 4. FFT Analysis of ADS-937 0.63 Number of Occurrences – 0.50 0 Codes 65,536 DNL (LSB's) 0 Digital Output Code 65,536 Figure 5. ADS-937 Histogram and Differential Nonlinearity 6 ® C27 OPT R2 OPT AIN 7 6 OPT SG3 +5VD 4 C23 OPT + 1 AIN AGND BIT2 1D 3 3 UNIPOLAR 4 3D 4D 6 5 REF. OUT GAIN ADJ UUT BIT7 ADS-937 –15VA 9 +15VA 10 +5VA -5VA AGND 13 DGND BIT8 BIT9 BIT10 BIT11 BIT12 BIT13 14 15 +15V 3 R3 +5V C24 + 14 X1 1 7 P3 EXT CLK 10 8 10uF C26 0.1uF 10 1 R6 13 51 4 U3 5 9 U3 8 6 C29 + 10uF C3 0.1uF 1 2 12 U3 +5VD JPR3 2 16 START CONVERT 11 (LSB) BIT16 17 BIT14 +5VD EOC BIT15 26 11 25 +5VD 24 C2 23 2 1D 22 21 20 19 18 3 4 12 C20 C9 0.1uF 10uF + 3D 5 6 5D 7 C10 0.1uF 8 9 11 6D 7D 8D LE 10 +5VD 74HCT573 4D U2 2D 20 1Q 2Q 3Q 4Q 5Q 6Q 7Q 8Q OC 19 18 17 16 15 14 13 BIT9 BIT10 BIT11 14 BIT12 BIT13 10 BIT14 8 BIT15 12 (LSB) BIT16 1 START CONVERT 6 4 2 12 18 16 0.1uF COMP. BIT6 27 BIT5 28 6 C25 0.1uF C5 0.1uF + C14 22uF –15V N.C. C17 8 + C16 22uF 7 5D 7 8 9 8D LE 10 74HCT573 6D 7D C4 0.1uF U1 5 C28 0.1uF 4 OFFSET ADJ. BIT4 29 BIT3 30 2D R4 20K +15V 2Q 3Q 4Q 5Q 6Q 7Q 8Q OC 31 1Q 2 20 18 17 16 15 14 13 12 1 (MSB) BIT1 32 SG4 2 –15V 1 "OFFSET ADJ." SG1 C12 OPT C1 0.1uF 19 (MSB) BIT1 BIT2 BIT3 30 BIT4 28 BIT5 26 BIT6 24 BIT7 22 BIT8 20 + C22 OPT C11 OPT +15V SG2 R1 P4 2– OPT AR1 AMPLIFIER OPTION 3 + ® –15V 34 32 33 31 29 27 25 23 21 19 2 JPR2 3 JPR2 "GAIN ADJ." R5 20K REF C15 10uF P1 + 26 25 P2 + 24 N.C. 23 10uF +15V +5VA C6 0.1uF + + + 7 N.C. C18 10uF +5VD –5V C19 10uF C8 0.1uF C7 0.1uF 11 +5VD –15V C21 10uF 22 21 17 15 13 11 9 7 5 3 1 EOC 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1 2 14 U3 7 3 ADS-937 Figure 6. ADS-937 Evaluation Board ® ® ADS-937 5000 4000 3000 2000 1000 0.00 This histogram represents the typical peak-to- peak noise (including quantization noise) associated with the ADS-937. Digital Output Code Figure 7. ADS-937 Grounded Input Histogram 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) PIN 1 INDEX 0.220 TYP. (6.86) 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) 0.05 TYP. (1.27) 0.90 TYP. (22.86) ORDERING INFORMATION MODEL NUMBER ADS-937MC ADS-937MM ADS-937/883 OPERATING TEMP. RANGE 0 to +70°C –55 to +125°C –55 to +125°C 32-PIN PACKAGE TDIP TDIP TDIP ACCESSORIES ADS-B937 Evaluation Board (without ADS-937) Receptacles for pc board mounting can be ordered through AMP, Inc., Part # 3-331272-8 (Component Lead Socket), 32 required. For availability of MIL-STD-883 product, contact DATEL. ® ® ISO 9001 R E G I S T E R E D DS-0306C 5/99 DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com Email: sales@datel.com Data Sheet Fax Back: (508) 261-2857 DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01 DATEL GmbH München, 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.