® ADS-942 ® 14-Bit, 2MHz Sampling A/D Converters PRODUCT OVERVIEW DATEL's ADS-942 is a functionally complete, 14-bit, 2MHz, sampling A/D converter. Its standard, 32-pin, triple-wide ceramic DIP contains a fastsettling sample/hold amplifier, a 14-bit subranging (two-pass) A/D converter, a precision reference, three-state output register and all the timing and control logic necessary to operate from a single start convert pulse. The ADS-942 is optimized for wideband frequency-domain applications and is fully FFT tested. The ADS-942 requires ±15V and +5V supplies and typically consumes 2.9 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 ANALOG GROUND ANALOG GROUND EOC FEATURES 14-bit resolution 2MHz minimum throughput Functionally complete Internal reference and sample/hold -85dB total harmonic distortion 78dB signal-to-noise ratio Full Nyquist-rate sampling Small 32-pin DIP Low-power, 2.9 Watts 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 28 BIT 3 OUT 3-STATE OUTPUT REGISTER OFFSET CIRCUIT OFFSET ADJUST 5 DIGITAL CORRECTION LOGIC REF +10V REF. OUT 1 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 6, 14, 15 13 8 SIGNAL GROUND +5V SUPPLY DIGITAL GROUND +15V SUPPLY ANALOG GROUND –15V SUPPLY CODING SELECT Figure 1. ADS-942 Functional Block Diagram DATEL • 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 1 of 6 ® ADS-942 ® 14-Bit, 2MHz Sampling A/D Converters 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) ABSOLUTE MAXIMUM RATINGS LIMITS 0 to +16 0 to –16 0 to +6.0 –0.3 to +VDD +0.3 ±25 300 OUTPUTS 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 DATEL MIN. TYP. MAX. UNITS — — 4.9 — 0 to +10 ±5 2.5 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 –0.75 –0.95 –0.99 ±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 • MIN. Output Coding Logic Level Logic "1" +2.4 Logic "0" — Logic Loading "1" — Logic Loading "0" — Internal Reference Voltage, +25°C +9.98 Drift — External Current — 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) dc to 100kHz 73 100kHz to 500kHz 72 500kHz to 1MHz — Spurious Free Dyn. Range dc to 100kHz — 100 to 500kHz — 500kHz to 1MHz — Two-tone IMD Distortion (fin = 100kHz, 240kHz, fs = 2.0Mhz, –0.5dB) — 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 — 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 +14.25 –15V Supply –14.25 +5V Supply +4.75 Power Supply Currents +15V Supply — –15V Supply — +5V Supply — Power Dissipation — Power Supply Rejection — 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA TYP. MAX. UNITS Staight Bin./Offset Bin./Two's Comp. Comp. Bin./Comp. Offset Bin./C2C • Tel: (508) 339-3000 • — — — — — +0.4 –160 +6.4 Volts Volts μA mA +10.0 ±13 — +10.02 ±30 5 Volts ppm/°C mA –85 –80 –77 — –75 — dB dB dB 78 75 73 — — — dB dB dB 78 75 72 — — — dB dB dB –86 –81 –78 –77 –75 — dB dB dB –85 — dB 6 1.75 ±250 — — — — — 10 ±10 MHz MHz V/μs ns ps 120 250 150 450 ns ns — — 85 1000 250 — — — 2000 — MHz MHz dB ns μVrms +15.0 –15.0 +5.0 +15.75 –15.75 +5.25 Volts Volts Volts +65 –80 +150 2.9 — +87 –105 +185 3.5 ±0.05 mA mA mA Watts %FSR%V www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 2 of 6 ® ADS-942 ® 14-Bit, 2MHz Sampling A/D Converters 3. Full-Scale Adjustment Set the output of the voltage reference used in step 2 to the value shown in Table 2. PHYSICAL/ENVIRONMENTAL Operating Temp. Range, Case ADS-942MC, MC-C ADS-942ME, ME-C Storage Temperature Range Package Type Weight 0 — +70 °C –40 — +100 °C –65 — +150 °C 32-pin, metal-sealed, ceramic TDIP 0.46 ounces (13 grams) Footnote: Same specification as In-Band Harmonics and Peak Harmonics. 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). 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 for straight binary/offset binary or between 00 0000 0000 0000 and 00 0000 0000 0001 with pin 8 tied high for complementary binary/complementary offset binary. Two’s complement coding requires using pin 31. 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. 4. To confirm proper operation of the device, vary the precision reference voltage source to obtain the output coding listed in Table 3. 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. 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). INPUT RANGE INPUT PIN TIE TOGETHER 0 +10V Pin 3 Pins 2 and 4 ±5V Pin 3 Pins 1 and 2 Table 1. Input Connections INPUT RANGE ZERO ADJUST +½ LSB GAIN ADJUST FS –1½ LSB 0 to +10V +305μV +9.999085V ±5V +305μV +4.999085V Table 2. Zero and Gain Adjustments START CONVERT N 35ns min., 50ns typ., 60 ns max Conversion Time 300ns typ., 325ns max. EOC 10ns typ. 15ns max. INTERNAL S/H 35ns typ. Hold 30ns max. DATA N-1 VALID DATA N VALID INVALID DATA 200ns max. 300ns min. 1. Connect the converter per Figure 3 and Table 1 for the appropriate 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 LED's are used on the outputs for calibration purposes. 150ns max. Aquisition Time 350ns min. OUTPUT DATA CALIBRATION PROCEDURE N+1 35ns max.. Note: Scale is approximately 25ns per division. Figure 2. ADS-942 Timing Diagram 2. Zero Adjustments 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. 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). 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). Two's complement coding requires using BIT 1 OUT (MSB) (pin 31). With pin 8 tied low, adjust the trimpot until the code flickers between 00 0000 0000 0000 and 00 0000 0000 0001. DATEL • 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 3 of 6 ® ADS-942 ® 14-Bit, 2MHz Sampling A/D Converters ZERO/OFFSET ADJUST 20k +15V +5V 0.1μF 4.7μF 0.1μF + –15V 4.7μF 31 BIT 1 OUT (MSB) 30 BIT 1 OUT (MSB) 29 BIT 2 OUT 28 BIT 3 OUT DIGITAL 11 GROUND + +15V 5 OFFSET ADJUST 10 4.7μF –15V 27 BIT 4 OUT 26 BIT 5 OUT 12 25 BIT 6 OUT 24 BIT 7 OUT 6, 14, 15 ANALOG GROUND 23 BIT 8 OUT 22 BIT 9 OUT 21 BIT 10 OUT 0.1μF 13 20 BIT 11 OUT 19 BIT 12 OUT ADS-942 GAIN ADJUST 18 BIT 13 OUT 17 BIT 14 OUT (LSB) 7 OVERFLOW 16 EOC 3 ANALOG INPUT 0 to +10V 100 4 SIGNAL GROUND CODING SELECT 8 +5V START CONVERT 32 1 +10V REF. OUT 0.1μF 4.7μF ENABLE 9 BIPOLAR 2 Figure 3. Typical ADS-942 Connection Diagram Removing System Errors Use external potentiometers to remove system errors or to reduce the small initial errors to zero. Use a 100Ω trimpot in series with the analog input for gain adjustment. Use a fixed 50Ω resistor instead of the trimpot for operation 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 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. without adjustment. 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. 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 • 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 4 of 6 ® ADS-942 ® 14-Bit, 2MHz Sampling A/D Converters THERMAL REQUIREMENTS 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. 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 0 –10 Amplitude Relative to Full Scale (dB) –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-942 FFT Analysis DATEL • 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 5 of 6 ® ADS-942 ® 14-Bit, 2MHz 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-942MC 0 to +70°C TDIP No ADS-942MC-C 0 to +70°C TDIP Yes ADS-942ME –40 to +100°C TDIP No ADS-942ME-C –40 to +100°C TDIP Yes ACCESSORIES ADS-EVAL4 HS-32 Evaluation Board (without ADS-942) Heat Sink for all ADS-942 models Receptacles for PC mounting can be ordered through AMP Inc., Part # 3-331272-8 (Component Lead Socket), 32 required. DATEL 11 Cabot Boulevard, Mansfield, MA 02048-1151 USA ITAR and ISO 9001/14001 REGISTERED . 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. © 2013 www.datel.com • e-mail: [email protected] 30 Apr 2013 MDA_ADS-942.C02 Page 6 of 6