ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters PRODUCT OVERVIEW The ADS-953 is an 18-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 –95dB peak harmonic distortion (THD), makes the ADS-953 the ideal choice for both time-domain (medical imaging, scanners, process control) and frequency-domain (radar, telecommunications, spectrum analysis) applications. Packaged in a 32-pin, side-brazed, metalsealed, ceramic TDIP, the functionally complete ADS-953 contains a fast-settling 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, and the ADS-953 only requires the rising edge of the start convert pulse to operate. Requiring ±15V and ±5V supplies, the ADS953 typically dissipates 1.45 Watts. The device is offered with a bipolar (±5V) analog input range. Models are available for use in either commer- FEATURES 18-bit resolution 1MHz minimum sampling rate No missing codes over extended temperature range Very low power, 1.45 Watts Small, 32-pin, side-brazed, ceramic TDIP Edge-triggered Excellent performance, –95dB peak harmonics Ideal for both time and frequency-domain applications Low cost cial (0 to +70°C) or extended (–40 to +110°C) operating temperature ranges. A proprietary, auto-calibrating, error-correcting circuit enables the device to achieve specified performance over the full military temperature range. PIN INPUT/OUTPUT CONNECTIONS FUNCTION PIN FUNCTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 BIT 2 BIT 1 (MSB) ANALOG GROUND ANALOG INPUT +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 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 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 BIT 17 BIT 18 (LSB) BLOCK DIAGRAM BIT 1 (MSB) 1 BIT 2 32 BIT 3 BUFFER ANALOG INPUT 4 2 – 31 BIT 4 FLASH ADC 1 S/H + 30 BIT 5 29 BIT 6 28 BIT 7 REF DAC Σ +5V REFERENCE OUT 5 COMPENSATION 7 FLASH ADC 2 AMP 27 BIT 8 DIGITAL CORRECTION LOGIC GAIN ADJUST 6 GAIN CIRCUIT 26 BIT 9 25 BIT 10 24 BIT 11 23 BIT 12 22 BIT 13 21 BIT 14 20 BIT 15 19 BIT 16 18 BIT 17 17 BIT 18 (LSB) START CONVERT 16 TIMING AND CONTROL LOGIC EOC 15 10 +5V ANALOG SUPPLY 11 –5V ANALOG SUPPLY 3, 12 14 ANALOG GROUND +5V DIGITAL SUPPLY 9 8 +15V SUPPLY 13 –15V SUPPLY DIGITAL GROUND Figure 1. ADS-953 Functional Block Diagram DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 1 of 6 ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters ABSOLUTE MAXIMUM RATINGS PARAMETERS LIMITS +15V Supply (Pin 9) 0 to +16 –15V Supply (Pin 8) 0 to –16 +5V Supply (Pins 10, 14) 0 to +6 –5V Supply (Pin 11) 0 to –6 Digital Input (Pin 16) –0.3 to +VDD +0.3 Analog Input (Pin 4) ±15 Lead Temperature (10 seconds) +300 UNITS Volts Volts Volts Volts Volts Volts °C PARAMETERS Operating Temp. Range, Case ADS-953MC ADS-953ME Thermal Impedance θjc θca Storage Temperature Range Package Type Weight PHYSICAL/ENVIRONMENTAL MIN. TYP. 0 –40 — — MAX. UNITS +70 +110 °C °C — 5 — °C/Watt — 22 — °C/Watt –65 — +150 °C 32-pin,side-brazed, metal-sealed, ceramic TDIP 0.46 ounces (13 grams) FUNCTIONAL SPECIFICATIONS (TA = +25°C, ±VCC = ±15V, ±VDD = ±5V, 1MHz sampling rate, and a minimum 1 minute warmup ➀ unless otherwise specified.) ANALOG INPUT MIN. — Input Voltage Range d Input Resistance — Input Capacitance — DIGITAL INPUT Logic Levels Logic "1" +2.0 Logic "0" — Logic Loading "1" — Logic Loading "0" — Start Convert Positive Pulse Width ➂ 20 STATIC PERFORMANCE Resolution — Integral Nonlinearity (fin = 10kHz) — Differential Nonlinearity (fin = 10kHz) –0.95 Full Scale Absolute Accuracy — Bipolar Zero Error (Tech Note 2) — Bipolar Offset Error (Tech Note 2) — Gain Error (Tech Note 2) — No Missing Codes (fin = 10kHz) 18 DYNAMIC PERFORMANCE (500kHz SAMPLING RATE) Peak Harmonics (–0.5dB) dc to 1kHz — dc to 100kHz — Total Harmonic Distortion (–0.5dB) dc to 100kHz — Signal-to-Noise Ratio (w/o distortion, –0.5dB) dc to 100kHz 91 Signal-to-Noise Ratio f (& distortion, –0.5dB) dc to 100kHz 76 DC Noise — Two-Tone Intermodulation Distortion (fin = 100kHz, 240kHz, fs = 500kHz, –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 ➄ — A/D Conversion Rate 1 ANALOG OUTPUT Internal Reference Voltage +4.95 Drift — External Current — +25°C TYP. ±5 500 7 MAX. — — 15 MIN. — — — 0 TO +70°C TYP. ±5 500 7 MAX. — — 15 MIN. — — — –40 TO +110°C TYP. ±5 500 7 MAX. — — 15 UNITS Volts Ω pF — — — — 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 18 ±10 ±0.5 ±0.1 ±0.1 ±0.1 ±0.1 — — — +1 ±0.25 ±0.15 ±0.2 ±0.25 — — — –0.95 — — — — 18 18 ±10 ±0.5 ±0.25 ±0.15 ±0.2 ±0.25 — — — +1 ±0.4 ±0.25 ±0.3 ±0.4 — — — –0.95 — — — — 18 18 ±15 ±0.50 ±0.4 ±0.25 ±0.3 ±0.4 — — — +1.25 ±0.8 ±0.5 ±0.6 ±0.9 — Bits LSB LSB %FSR %FSR %FSR % Bits –95 –87 –93 — — — –95 — –93 — — — –82 –80 — — dB dB –85 –80 — –85 –80 — –81 — dB 93 — 91 93 — — 92 — dB 84 76 — — 76 — 84 76 — — — — 80 76 — — dB μVrms –85 — — –85 — — –81 — d 1.2 1.1 84 TBD +20 5 260 500 — — — — — — — — 1000 — — — — — — — — — 1 1.2 1.1 84 TBD +20 5 260 500 — — — — — — — — 1000 — — — — — — — — — 1 1.2 1.1 84 TBD +20 5 260 500 — — — — — — — — 1000 — MHz MHz dB V/μs ns ps rms ns ns MHz +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 DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 2 of 6 ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters 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 MIN. +25°C TYP. MAX. MIN. +2.4 — — — — — — — — +0.4 –4 +4 +2.4 — — — +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 — — — — — — +29 –15 +104 –54 1.45 — 40 –25 125 –70 1.65 ±0.05 — — — — — — +29 –15 +104 –54 1.45 — Footnotes: ➀ All power supplies should be on before applying a start convert pulse. All supplies and the clock (START CONVERT) must be present during warmup periods. The device must be continuously converting during this time. ➁ Contact DATEL for other input voltage ranges. ➂ 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 lower than 1MHz may be used. DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA 0 TO +70°C TYP. MIN. –40 TO +110°C TYP. MAX. UNITS +2.4 — — — — — — — — +0.4 –4 +4 Volts Volts mA mA +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 40 –25 125 –70 1.65 ±0.05 — — — — — — +29 –15 +104 –54 1.45 — 40 –25 125 –70 1.65 ±0.05 mA mA mA mA Watts %FSR/%V MAX. — — — +0.4 — –4 — +4 Complementary Offset Binary ➃ Effective bits is equal to: (SNR + Distortion) – 1.76 + 20 log Full Scale Amplitude Actual Input Amplitude 6.02 ➄ This is the time required before the A/D output data is valid once the analog input is back within the specified range. • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 3 of 6 ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters TECHNICAL NOTES THERMAL REQUIREMENTS 1. Obtaining fully specified performance from the ADS-953 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 (3, 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 10μF 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. 2. The ADS-953 achieves its specified accuracies without the need for external calibration. If required, the device's small initial 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 warmup. To avoid interaction, always adjust offset before gain. Float pin 6 if not using gain adjust circuits. All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70°C and –40 to +110°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. Electricallyinsulating, 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. Applying a start convert pulse while a conversion is in progress (EOC = logic "1") will initiate a new and probably inaccurate conversion cycle. Data for the interrupted and subsequent conversions will be invalid. CALIBRATION PROCEDURE Gain Adjust 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-953's initial accuracy errors and may not be able to compensate for additional system errors. 1. Apply –4.999943V to the ANALOG INPUT (pin 4). 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 applied input voltage to obtain the output coding listed in Table 2. 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-953, offset adjusting is normally accomplished when the analog input is 0 minus ½LSB (–19μV). See Table 2 for the proper bipolar output coding. Gain adjusting is accomplished when the analog input is at nominal full scale minus 1½LSB's (–4.999943V). 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 bipolar zero/offset adjust, apply –19μV to the ANALOG INPUT (pin 4). 3. Adjust the offset potentiometer until the output code flickers equally between 01 1111 1111 1111 1111 and 10 0000 0000 0000 0000. DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA INPUT VOLTAGE RANGE ZERO ADJUST (–½ LSB) GAIN ADJUST (–FS +1½ LSB) ±5V –19μV –4.999943 Table 1. Input Connections BIPOLAR SCALE +FS –1 LSB +3/4 FS +1/2 FS 0 –1/2 FS –3/4 FS –FS +1 LSB –FS COMPLEMENTARY OFFSET BINARY OUTPUT CODING INPUT RANGE ±5V MSB LSB +4.999962 00 0000 0000 0000 0000 +3.750000 00 0111 1111 1111 1111 +2.500000 00 1111 1111 1111 1111 +0.000000 01 1111 1111 1111 1111 –2.500000 10 1111 1111 1111 1111 –3.750000 11 0111 1111 1111 1111 –4.999962 11 1111 1111 1111 1110 –5.000000 11 1111 1111 1111 1111 Table 2. Output Coding • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 4 of 6 ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters Pin 5 (ADS-953) 10k Ω 6 GAIN ADJUST 15 EOC 2 BIT 1 (MSB) 1 BIT 2 32 BIT 3 14 +5V DIGITAL 31 BIT 4 30 BIT 5 0.1μF 10μF 13 DIGITAL GROUND + 10μF 0.1μF + 10μF 27 BIT 8 26 BIT 9 0.1μF 25 BIT 10 12 ANALOG GROUND 24 BIT 11 23 BIT 12 ADS-953 9 22 BIT 13 21 BIT 14 20 BIT 15 10 +5V ANALOG 19 BIT 16 + 10μF 18 BIT 17 0.1μF 3 ANALOG GROUND + –5V ANALOG 28 BIT 7 8 –15V +15V 29 BIT 6 10μF 0.1μF 17 BIT 18 (LSB) 16 START CONVERT 11 5 +5V REF. OUT 0.1μF 47μF 7 COMPENSATION + 4 ANALOG INPUT 10μF Figure 2. Typical ADS-953 Connection Diagram N START CONVERT N+1 500ns typ. 5ns typ. INTERNAL S/H Acquisition Time 740ns typ. 260ns typ. Hold 65ns typ. EOC Conversion Time 730ns typ. 20ns typ. OUTPUT DATA Invalid Data 20ns N Data N-1 Valid Data N-2 Valid 980ns typ. Scale is approximately 50ns per division. Figure 3. ADS-953 Timing Diagram DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 5 of 6 ADS-953 18-Bit, 1MHz, Low-Distortion Sampling A/D Converters 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) 0.90 TYP. (22.86) 0.175 TYP (4.45) 0.05 TYP. (1.27) ORDERING INFORMATION MODEL NUMBER OPERATING TEMP. RANGE 32-PIN PACKAGE ADS-953MC 0 to +70°C TDIP ADS-953ME –40 to +110°C TDIP ACCESSORIES ADS-B951* Evaluation Board (without ADS-951) Receptacles for PC 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. * NOTE: The ADS-951 evalution board is used for the AD-953, as the ADS-951 and ADS-953, share a common pinout DATEL is a registered trademark of DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA DATEL, 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. ITAR and ISO 9001/14001 REGISTERED © 2015 DATEL, Inc. www.datel.com • e-mail: [email protected] 11 Sep 2015 MDA_ADS-953.B03 Page 6 of 6