ADS-937 16-Bit, 1MHz Sampling A/D Converters FEATURES N 16-bit resolution N 1MHz sampling rate N No missing codes over full military temperature range N Very low power, 1.25 Watts N Small, 32-pin, side-brazed ceramic TDIP N Edge-triggered N Excellent performance N Ideal for both time and frequency-domain applications PIN FUNCTION PIN FUNCTION N Low cost 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ANALOG INPUT GROUND UNIPOLAR OFFSET ADJUST +5V REFERENCE OUT GAIN ADJUST COMPENSATION -15V SUPPLY +15V SUPPLY +5V SUPPLY -5V SUPPLY GROUND GROUND +5V SUPPLY EOC START CONVERT 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 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) INPUT/OUTPUT CONNECTIONS 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 error correction circuitry. Digital input and output levels are TTL. The 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. For full details go to www.murata-ps.com/rohs Figure 1. ADS-937 Functional Block Diagram www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 1 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters 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) PHYSICAL/ENVIRONMENTAL LIMITS UNITS 0 to +16 0 to –16 0 to +6 0 to -6 –0.3 to +VDD +0.3 ±15 +300 Volts Volts Volts Volts Volts Volts °C PARAMETERS Operating Temp. Range, Case ADS-937MC ADS-937MM/883 Thermal Impedance Θjc Θca Storage Temperature Range Package Type Weight MIN. TYP. MAX. UNITS 0 –55 — — +70 +125 °C °C — 5 — °C/Watt — 22 — °C/Watt –65 — +150 °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 ~ unless otherwise specified.) +25°C ANALOG INPUT Input Voltage Range Bipolar Unipolar Input Resistance Input Capacitance MIN. TYP. 0 to +70°C MAX. MIN. –55 to +125°C TYP. MAX. MIN. TYP. MAX. UNITS — — — — ±5 0 to -10 1 7 — — — 15 — — — — ±5 0 to -10 1 7 — — — 15 — — — — ±5 0 to -10 1 7 — — — 15 Volts Volts kΩ pF +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 — — –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 — — –90 –88 -84 -81 — — –90 –88 -84 -81 — — –88 –87 -83 -80 dB dB — — –87 –86 -82 -81 — — –87 –86 -82 -81 — — –86 –85 -81 -80 dB dB 85 84 88 87 — — 85 84 88 87 — — 84 83 87 87 — — dB dB 81 80 — 85 84 110 — — — 81 80 — 85 84 110 — — — 80 78 — 84 83 110 — — — dB dB μVrms — –85 — — –85 — — –85 — dB — — — — — — 4.5 4 84 ±33 +20 5 — — — — — — — — — — — — 4.5 4 84 ±33 +20 5 — — — — — — — — — — — — 4.5 4 84 ±33 +20 5 — — — — — — MHz MHz dB V/μs ns ps rms — — 1 260 500 — 300 1000 — — — 1 260 500 — 300 1000 — — — 1 260 500 — 300 1000 — ns ns MHz DIGITAL INPUTS 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) 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 www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 2 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters MIN. +25°C TYP. MAX. MIN. 0 TO +70°C TYP. MAX. +4.95 — — +5.0 ±30 1 +5.05 — — +4.95 — — +5.0 ±30 1 +5.05 — — +4.95 — — +5.0 ±30 1 +5.05 — — Volts ppm/°C mA — — — — — +0.4 –4 +4 +2.4 — — — — — — — — +0.4 –4 +4 Volts Volts mA mA MIN. –55 TO +125°C TYP. MAX. UNITS ANALOG OUTPUT Internal Reference Voltage Drift External Current DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding +2.4 — — +2.4 — — +0.4 — — — –4 — — — +4 — (Offset) Binary / Complementary (Offset) Binary 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 +15.5 –15.5 +5.25 –5.25 +14.5 –14.5 +4.75 –4.75 +15.0 –15.0 +5.0 –5.0 +15.5 –15.5 +5.25 –5.25 +14.5 –14.5 +4.75 –4.75 +15.0 –15.0 +5.0 –5.0 +15.5 –15.5 +5.25 –5.25 Volts Volts Volts Volts — — — — — — +7 –8 +133 -72 1.25 — +9 -10 +145 -80 1.35 ±0.01 — — — — — — +7 -8 +133 -72 1.25 — +9 -10 +145 -80 1.35 ±0.01 — — — — — — +7 -8 +133 -72 1.25 — +9 -10 +145 -80 1.35 ±0.01 mA mA mA mA Watts %FSR/%V Footnotes: ~ 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. Effective bits is equal to: (SNR + Distortion) – 1.76 + Full Scale Amplitude Actual Input Amplitude 6.02 Contact Murata-PS for other input voltage ranges. 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. 20 log 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 ground pins 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. The device's +5V supply pins are not connected to each other internally and should be connected to a clean analog +5V supply. 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. www.murata-ps.com 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. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 3 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters 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. 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. Setting Output Coding Selection (Pin 35) INPUT VOLTAGE RANGE ±5V 0 to -10V INPUT PIN TIE TOGETHER Pin 1 Pin 1 Pins 2 and 3 Pins 3 and 5 2. For unipolar or bipolar zero/offset adjust, apply –76.3μV to the ANALOG INPUT (pin 1). Table 2. Output Coding COMPLEMENTARY BINARY COMPLEMENTARY OFFSET BINARY OUTPUT CODING UNIPOLAR SCALE INPUT VOLTAGE 0 to -10V –FS +1 LSB -9.999847 1111 1111 1111 1111 0000 0000 0000 0000 +4.999847 +FS -1 LSB –7/8 FS -8.750000 1110 0000 0000 0000 0001 1111 1111 1111 +3.750000 +3/4 FS –3/4 FS -7.500000 1100 0000 0000 0000 0011 1111 1111 1111 +2.500000 +1/2 FS –1/2 FS -5.000000 1000 0000 0000 0000 0111 1111 1111 1111 +0.000000 0 –1/4 FS -2.500000 0100 0000 0000 0000 1011 1111 1111 1111 -2.500000 –1/2 FS –1/8 FS -1.250000 0010 0000 0000 0000 1101 1111 1111 1111 -3.750000 –3/4 FS –1 LSB -0.000153 0000 0000 0000 0001 1111 1111 1111 1110 -4.999847 –FS +1 LSB 0.000000 0000 0000 0000 0000 1111 1111 1111 1111 -5.000000 –FS 0 MSB LSB www.murata-ps.com MSB LSB INPUT RANGE ±5V BIPOLAR SCALE Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 4 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters Figure 2. Typical ADS-937 Connection Diagram Figure 3. ADS-937 Timing Diagram www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 5 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters Figure 4. FFT Analysis of ADS-937 Figure 5. ADS-937 Histogram and Differential Nonlinearity www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 6 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters Figure 6. ADS-937 Evaluation Board. www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 7 of 8 ADS-937 16-Bit, 1MHz Sampling A/D Converters This histogram represents the typical peak-to-peak noise (including quantization noise) associated with the ADS-937. Figure 7. ADS-937 Grounded Input Histogram MECHANICAL DIMENSIONS INCHES (mm) ORDERING INFORMATION MODEL NUMBER OPERATING TEMPERATURE RANGE 32-PIN PACKAGE ADS-937MC 0 to +70ºC TDIP ADS-937MM -55 to +125ºC TDIP ADS-937/883 -55 to +125ºC TDIP ACCESSORIES ADS-B937 Evaluation Board (without ADS937) Receptacles for PC board mounting can be ordered through AMP, Inc., Part # 3-331272-8 (Component Lead Socket), 32 required. For availabilty of MIL-STD-883 product, contact Murata Power Solutions. USA: Mansfield (Ma), Tel: (508) 339-3000, email: [email protected] Canada: Toronto, Tel: (866) 740 1232, email: [email protected] Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 www.murata-ps.com email: [email protected] ISO 9001 REGISTERED Murata Power Solutions, Inc. 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. © 2008 Murata Power Solutions, Inc. www.murata-ps.com UK: Milton Keynes, Tel: +44 (0)1908 615232, email: [email protected] France: Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: [email protected] Germany: München, Tel: +49 (0)89-544334-0, email: [email protected] Japan: Tokyo, Tel: 3-3779-1031, email: [email protected] Osaka, Tel: 6-6354-2025, email: [email protected] Website: www.murata-ps.jp China: Shanghai, Tel: +86 215 027 3678, email: [email protected] Guangzhou, Tel: +86 208 221 8066, email: [email protected] Technical enquiries email: [email protected], tel: +1 508 339 3000 MDA_ADS-937.A01 Page 8 of 8