ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters PRODUCT OVERVIEW DATEL's ADS-942A is a functionally complete, 14-bit, 2MHz, sampling A/D converter. Packaged in a 32-pin TDIP, the unit contains a fast-settling sample/hold amplifier, a 14-bit subranging (two-pass) A/D converter, a precision reference, three-state output register, and all the timing/con- FEATURES 14-bit resolution 2MHz minimum throughput Low-power, 2.2 Watts Functionally complete Internal reference and S/H amplifier 78dB signal-to-noise ratio Full Nyquist-rate sampling Small 32-pin TDIP trol logic necessary to operate from a single start convert pulse. The ADS-942AA is optimized for wideband frequency-domain applications and is fully FFT tested. The ADS-942AA requires ±15V and ±5V supplies and typically consumes 2.2 Watts. INPUT/OUTPUT CONNECTIONS PIN FUNCTION PIN FUNCTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 +10V REF. OUT BIPOLAR ANALOG INPUT SIGNAL GROUND OFFSET ADJUST ANALOG GROUND OVERFLOW CODING SELECT ENABLE +5V SUPPLY DIGITAL GROUND +15V SUPPLY –15V SUPPLY –5V SUPPLY ANALOG GROUND EOC 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 START CONVERT BIT 1 OUT (MSB) BIT 1 OUT (MSB) BIT 2 OUT BIT 3 OUT BIT 4 OUT BIT 5 OUT BIT 6 OUT BIT 7 OUT BIT 8 OUT BIT 9 OUT BIT 10 OUT BIT 11 OUT BIT 12 OUT BIT 13 OUT BIT 14 OUT (LSB) BLOCK DIAGRAM DAC 31 BIT 1 OUT (MSB) 30 BIT 1 OUT (MSB) 29 BIT 2 OUT REGISTER S2 FLASH ADC BIPOLAR 2 BUFFER S/H REGISTER ANALOG INPUT 3 S1 3-STATE OUTPUT REGISTER OFFSET CIRCUIT OFFSET ADJUST 5 DIGITAL CORRECTION LOGIC REF +10V REF. OUT 1 28 BIT 3 OUT 27 BIT 4 OUT 26 BIT 5 OUT 25 BIT 6 OUT 24 BIT 7 OUT 23 BIT 8 OUT 22 BIT 9 OUT 21 BIT 10 OUT 20 BIT 11 OUT 19 BIT 12 OUT 18 BIT 13 OUT 17 BIT 14 OUT (LSB) START CONVERT 32 TIMING AND CONTROL LOGIC 9 ENABLE EOC 16 7 OVERFLOW 4 10 11 12 13 14 6, 15 8 SIGNAL GROUND +5V SUPPLY DIGITAL GROUND +15V SUPPLY –15V SUPPLY –5V SUPPLY ANALOG GROUND CODING SELECT Figure 1. ADS-942A Functional Block Diagram DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 23 Jul 2015 MDA_ADS-942A.B02 Page 1 of 6 ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters ABSOLUTE MAXIMUM RATINGS PARAMETERS +15V Supply (Pin 12) –15V Supply (Pin 13) +5V Supply (Pin 10) Digital Inputs (Pin 8, 9, 32) Analog Input (Pin 3) Lead Temp. (10 seconds) OUTPUTS LIMITS 0 to +16 0 to –16 0 to +6.0 –0.3 to +VDD +0.3 ±25 300 UNITS Volts Volts Volts Volts Volts °C FUNCTIONAL SPECIFICATIONS (TA = +25°C, ±VCC = ±15V ±VDD = +5V, 2MHz sampling rate, and a minimum 7 minute warmup unless otherwise specified.) ANALOG INPUTS Input Voltage Range Unipolar Bipolar Input Impedence Input Capacitance DIGITAL INPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" PERFORMANCE Integral Non-Linearity (fin = 1MHz) +25°C 0 to +70°C –40 to +100°C Differential Non-Linearity (fin = 1MHz) +25°C 0 to +70°C –40 to +100°C Full Scale Absolute Accuracy +25°C 0 to +70°C –40 to +100°C Unipolar Zero Error +25°C (see Figure 3) 0 to +70°C –40 to +100°C Bipolar Zero Error +25°C (see Figure 3) 0 to +70°C –40 to +100°C Bipolar Offset Error +25°C (see Figure 3) 0 to +70°C –40 to +100°C Gain Error +25°C (see Figure 3) 0 to +70°C –40 to +100°C No Missing Codes (fin = 500kHz) 14 Bits 13 Bits Resolution MIN. TYP. MAX. UNITS — — 2.2 — 0 to +10 ±5 5 7 — — — 15 Volts Volts kΩ pF +2.0 — — — — — — — — +0.5 +5 –600 Volts Volts μA μA — — — ±1 ±1 ±2 ±2 ±2 ±3 LSB LSB LSB — –0.95 –1 ±0.5 ±0.75 ±1 ±0.75 ±0.95 +2.5 LSB LSB LSB — — — ±0.1 ±0.12 ±0.45 ±0.122 ±0.36 ±0.85 %FSR %FSR %FSR — — — ±0.05 ±0.1 ±0.2 ±0.122 ±0.2 ±0.3 %FSR %FSR %FSR — — — ±0.05 ±0.1 ±0.2 ±0.122 ±0.2 ±0.3 %FSR %FSR %FSR — — — ±0.1 ±0.12 ±0.5 ±0.2 ±0.3 ±0.8 %FSR %FSR %FSR — — — ±0.018 ±0.12 ±0.6 ±0.122 ±0.3 ±0.8 %FSR %FSR %FSR 0 to +70°C –40 to +100°C 14 Bits DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA MIN. TYP. MAX. UNITS Staight Bin./Offset Bin./Two's Comp. Comp. Bin./Comp. Offset Bin./C2C Output Coding Logic Level Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Internal Reference Voltage, +25°C Drift External Current +2.4 — — — — — — — — +0.4 –160 +6.4 Volts Volts μA mA +9.98 — — +10.0 ±13 — +10.02 ±30 5 Volts ppm/°C mA –85 –80 –77 — –75 –70 dB dB dB 78 75 73 — — — dB dB dB 78 75 72 — — — dB dB dB –86 –81 –78 85 –77 –75 — — dB dB dB dB 6 1.75 250 — — — — — 10 ±10 MHz MHz V/μs ns ps — 250 150 450 ns ns — — 85 1000 250 — — — 2000 — MHz MHz dB ns μVrms +14.25 –14.25 +4.75 –4.75 +15.0 –15.0 +5.0 –5.0 +15.75 –15.75 +5.25 –5.25 Volts Volts Volts Volts — — — — — — +65 –80 +150 –55 2.9 — +87 –105 +185 –65 3.5 ±0.05 mA mA mA mA Watts %FSR%V DYNAMIC PERFORMANCE Total Harm. Distort. (–0.5dB) dc to 100kHz — 100kHz to 500kHz — 500kHz to 1MHz — Signal-to-Noise Ratio (w/o distortion, –0.5dB ) dc to 100kHz 74 100kHz to 500kHz 73 500kHz to 1MHz — Signal-to-Noise Ratio (and distortion, –0.5dB) c dc to 100kHz 73 100kHz to 500kHz 72 500kHz to 1MHz — Spurious Free Dyn. Range ➁ dc to 100kHz — 100 to 500kHz — 500kHz to 1MHz — Two-tone IMD ➂ — Input Bandwidth (–3dB) Small Signal (–20dB input) — Large Signal (–0.5dB input) — Slew Rate — Aperature Delay Time — Aperature Uncertainty — S/H Aquisition Time (to ±0.003%FSR) Sinusoidal (fin = 1MHz) — Step input (10V) — Conversion Rate Sinusoidal (fin = 1MHz) 2 Step input 1.3 Feedthrough Rejection (fin = 1MHz) — Overvoltage Recovery, ±12V — Noise — 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 • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 23 Jul 2015 MDA_ADS-942A.B02 Page 2 of 6 ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters PHYSICAL/ENVIRONMENTAL Operating Temp. Range, Case ADS-942AMC, AMC-C ADS-942AME, AM-C Storage Temperature Range Package Type Weight Two's complement coding requires using pin 31 (MSB). With pin 8 tied low, adjust the trimpot until the code flickers between 00 0000 0000 0000 and 00 0000 0000 0001. 0 — +70 °C –40 — +100 °C –65 — +150 °C 32-pin, metal-sealed, ceramic TDIP 0.46 ounces (13 grams) 3. Set the output of the voltage reference used in step 2 to the value shown in Table 2. Adjust the gain trimpot until the output code flickers equally between 11 1111 1111 1110 and 11 1111 1111 1111 with pin 8 tied low (straight binary/offset binary) or between 00 0000 0000 0000 and 00 0000 0000 0001 with pin 8 tied high (complementary binary/complementary offset binary). Footnotes: ➀ Effective bits is equal to: (SNR + Distortion) – 1.76 + 20 log Full Scale Amplitude Actual Input Amplitude Two's complement coding requires using pin 31 (MSB). With pin 8 tied low, adjust the gain trimpot until the output code flickers equally between 01 1111 1111 1110 and 01 1111 1111 1111. 6.02 ➁ Same specification as In-Band Harmonics and Peak Harmonics. ➂ Two-tone Intermodulation Distortion (IMD) conditions: fin = 100kHz, 240kHz, fs = 2MHz, –0.5dB. 4. To confirm proper operation of the device, vary the precision reference voltage source to obtain the output coding listed in Table 3. TECHNICAL NOTES 1. Rated performance requires using good high-frequency circuit board layout techniques. Connect the digital and analog grounds to one point, the analog ground plane beneath the converter. Due to the inductance and resistance of the power supply return paths, return the analog and digital ground separately to the power supplies. SIGNAL GROUND (pin 4) is not internally connected to ANALOG GROUND (pins 6, 15). INPUT RANGE INPUT PIN 0 +10V Pin 3 TIE TOGETHER Pins 2 and 4 ±5V Pin 3 Pins 1 and 2 Table 1. Input Connections 2. Bypass the analog and digital supplies and the +10V REF. OUT (pin 1) to ground with a 4.7μF, 25V tantalum electrolytic capacitor in parallel with a 0.1μF ceramic capacitor. 3. CODING SELECT (pin 8) is compatible with CMOS/TTL logic levels for those users desiring logic control of this function. There is an internal pull-up resistor on this pin; connect to +5V or leave open for logic 1. See the Calibration Procedure for selecting an output coding. INPUT ZERO ADJUST RANGE GAIN ADJUST +½ LSB FS –1½ LSB 0 to +10V +305μV +9.999085V ±5V +305μV +4.999085V Table 2. Zero and Gain Adjustments 4. To enable the three-state outputs, connect ENABLE (pin 9) to a logic "0" (low). To disable, connect pin 9 to a logic "1" (high). 5. OVERFLOW (pin 7) changes from low (logic "0") to high (logic "1") when the input voltage exceeds the input voltage range limits by 1LSB (610μV). START CONVERT N 35ns min., 50ns typ., 60 ns max CALIBRATION PROCEDURE N+1 35ns max.. 1. Connect the converter per Figure 3 and Table 1 for the ppropriate input voltage range. Apply a pulse of 35 nanoseconds minimum to START CONVERT (pin 32) at a rate of 200kHz. This rate is chosen to reduce flicker if LEDs are used on the outputs for calibration purposes. Conversion Time 300ns typ., 325ns max. EOC 10ns typ. 15ns max. INTERNAL S/H 35ns typ. Hold 2. Zero Adjustments 150ns max. Aquisition Time 350ns min. Apply a precision voltage reference source between ANALOG INPUT (pin 3) and SIGNAL GROUND (pin 4), then adjust the reference source output per Table 2. 30ns max. OUTPUT DATA For unipolar, adjust the zero trimpot so that the output code flickers equally between 00 0000 0000 0000 and 00 0000 0000 0001 with CODING SELECT (pin 8) tied low (straight binary) or between 11 1111 1111 1111 and 11 1111 1111 1110 with pin 8 tied high (complementary binary). DATA N VALID DATA N-1 VALID 300ns min. INVALID DATA 200ns max. Note: Scale is approximately 25ns per division. Figure 2. ADS-942A Timing Diagram For bipolar operation, adjust the trimpot until the code flickers equally between 10 0000 0000 0000 and 10 0000 0000 0001 with pin 8 tied low (offset binary) or between 01 1111 1111 1111 and 01 1111 1111 1110 with pin 8 tied high (complementary offset binary). DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 23 Jul 2015 MDA_ADS-942A.B02 Page 3 of 6 ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters ZERO/OFFSET ADJUST 20k: +15V 0.1μF + 4.7μF –5V 4.7μF 0.1μF 0.1μF + 4.7μF –15V 4.7μF 31 BIT 1 OUT(MSB) 30 BIT 1 OUT(MSB) 29 BIT 2 OUT 28 BIT 3 OUT 27 BIT 4 OUT 26 BIT 5 OUT 25 BIT 6 OUT 24 BIT 7 OUT 23 BIT 8 OUT DIGITAL 11 GROUND 14 12 + +15V 5 OFFSET ADJUST 10 + +5V –15V 0.1μF 22 BIT 9 OUT 21 BIT 10 OUT 20 BIT 11 OUT 19 BIT 12 OUT 6, 15 ANALOG GROUND 13 ADS-942A 18 BIT 13 OUT 17 BIT 14 OUT (LSB) 7 OVERFLOW GAIN ADJUST 16 EOC 0 to +10V 3 ANALOG INPUT 100: CODING SELECT +5V 8 4 SIGNAL GROUND START CONVERT 32 1 +10V REF. OUT 0.1μF 4.7μF ENABLE 9 BIPOLAR 2 Figure 3. Typical ADS-942A Connection Diagram Removing System Errors Use external trimpots to remove system errors or to reduce small initial errors to zero. Use a 100Ω trimpot in series with the analog input for gain adjustment; use a fixed 50Ω resistor in its place for operation without adjustment. STRAIGHT 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 RANGE 0 to +10V +9.999390 +8.750000 +7.500000 +5.000000 +2.500000 +1.250000 +0.000610 0.000000 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 OFFSET BINARY Use a 20kΩ trimpot with the wiper tied to OFFSET ADJUST (pin 5) for zero/ offset adjustment. Connect pin 5 to ANALOG GROUND (pin 6) for operation without zero/offset adjustment. COMP. BINARY OUTPUT CODING MSB LSB 00 0000 0000 0000 00 0111 1111 1111 00 1111 1111 1111 01 1111 1111 1111 10 1111 1111 1111 11 0111 1111 1111 11 1111 1111 1110 11 1111 1111 1111 COMP. OFF. BIN. MSB LSB 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 TWO'S COMP. INPUT RANGE ±5V +4.999390 +3.750000 +2.500000 0.000000 –2.500000 –3.750000 –4.999390 –5.000000 BIPOLAR SCALE +FS – 1LSB +3/4FS +1/2FS 0 –1/2FS –3/4FS –FS+1LSB –FS Table 3. Output Coding DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 23 Jul 2015 MDA_ADS-942A.B02 Page 4 of 6 ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters THERMAL REQUIREMENTS 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. 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. 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 AN-8, "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. 0 Amplitude Relative to Full Scale (dB) –10 –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 –120 –130 –140 –150 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Frequency (MHz) (fs = 2MHz, fin = 490kHz, Vin = –0.5dB, 16,384-point FFT) Figure 4. ADS-942A FFT Analysis DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 23 Jul 2015 MDA_ADS-942A.B02 Page 5 of 6 ADS-942A 14-Bit, 2MHzLow-Power Sampling A/D Converters MECHANICAL DIMENSIONS INCHES (mm) 1.72 MAX. (43.69) 32 Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) 17 Lead Material: Kovar alloy 1.11 MAX. (28.19) 1 Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 16 0.100 TYP. (2.540) 0.235 MAX. (5.969) 1.500 (38.100) 0.200 MAX. (5.080) +0.002 0.010 –0.001 (0.254) 0.190 MAX. (4.826) 0.018 ±0.002 (0.457) SEATING PLANE 0.025 (0.635) 0.100 (2.540) 0.040 (1.016) 0.900 ±0.010 (22.860) 0.100 (2.540) ORDERING INFORMATION MODEL NUMBER OPERATING TEMP. RANGE PACKAGE ROHS ADS-942AMC 0 to +70°C TDIP No ADS-942AMC-C 0 to +70°C TDIP Yes ADS-942AME –40 to +100°C TDIP No ADS-942AME-C –40 to +100°C TDIP Yes ACCESSORIES ADS-EVAL4 HS-32 Evaluation Board (without ADS942A) Heat Sink for all ADS-942A models Receptacles for PC mounting can be ordered through AMP Inc., Part # 3-331272-8 (Component Lead Socket), 32 required. 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] 23 Jul 2015 MDA_ADS-942A.B02 Page 6 of 6