® ® ADS-942A 14-Bit, 2MHz, Low-Power Sampling A/D Converters 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 INPUT/OUTPUT CONNECTIONS GENERAL DESCRIPTION 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/control logic necessary to operate from a single start convert pulse. The ADS-942A is optimized for wideband frequency-domain applications and is fully FFT tested. The ADS-942A requires ±15V and ±5V supplies and typically consumes 2.2 Watts PIN FUNCTION PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 +10V REF. OUT BIPOLAR AVALOG 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 FUNCTION 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) 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 (U.S.A.) • Tel: (508) 339-3000 Fax: (508) 339-6356 • For immediate assistance: (800) 233-2765 ® ® ADS-942A ABSOLUTE MAXIMUM RATINGS PARAMETERS +15V Supply (Pin 12) –15V Supply (Pin 13) +5V Supply (Pin 10) –5V Supply (Pin 14) Digital Inputs (Pin 8,9, 32) Analog Input (Pin 3) Lead Temp. (10 seconds) OUTPUTS 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 Output Coding Logic Level Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Internal Reference Voltage, +25°C Drift External Current FUNCTIONAL SPECIFICATIONS MIN. TYP. MAX. UNITS Input Voltage Range Unipolar Bipolar Input Impedence Input Capacitance — — 2.3 — 0 to +10 ±5 2.5 7 — — — 15 Volts Volts kΩ pF +2.0 — — — — — — — — +0.8 +10 –600 Volts Volts µA µA 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 100kHz to 500kHz 500kHz to 1MHz Signal-to-Noise Ratio (and distortion, –0.5dB) ➀ dc to 100kHz 100kHz to 500kHz 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 Aperture Delay Time Aperature Uncertainty S/H Acq. Time, (to ±0.003%FSR) Sinusoidal (fin = 1MHz) Step input (10V) Conversion Rate Sinusoidal (fin = 1MHz) Step input Feedthrough Rejection (fin = 1MHz) Overvoltage Recovery, ±12V Noise DIGITAL INPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" PERFORMANCE Integral Non-Linearity +25°C 0 to +70°C –40 to +85°C Differential Non-Linearity +25°C 0 to +70°C –40 to +85°C Full Scale Absolute Accuracy +25°C 0 to +70°C –40 to +85°C Unipolar Zero Error +25°C 0 to +70°C –40 to ±85°C Bipolar Zero Error +25°C 0 to +70°C –40 to +85°C Bipolar Offset Error +25°C 0 to +70°C –40 to +85°C Gain Error +25°C 0 to +70°C –40 to +85°C No Missing Codes (fin = 500kHz) 14 Bits 13 Bits Resolution — — — ±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 % % % TYP. MAX. UNITS Staight Bin./Offset Bin./2's Comp. Comp. Bin./Comp. Offset Bin./C2C +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 –76 –75 — dB dB dB 74 73 — 78 75 73 — — — dB dB dB 73 72 — 78 75 72 — — — dB dB dB — — — — –86 –81 –78 85 –77 –75 — — dB dB dB dB — — — — — 6 1.75 ±250 — — — — — ±10 5 MHz MHz V/µs ns ps, ms — — — 250 150 450 ns ns 2 1.3 — — — — MHz MHz — — — 85 1000 250 — 2000 — 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 –19 +150 –55 2.2 — +80 –35 +175 –65 2.6 ±0.03 mA mA mA mA Watts %FSR%V DYNAMIC PERFORMANCE (TA = +25°C, ±VCC = ±15V, ±VDD = ±5V, 2MHz sampling rate, and a minimum 7 minute warmup ➀ unless otherwise specified.) ANALOG INPUTS MIN. 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 0 to +70°C –40 to +85°C 14 Bits PHYSICAL/ENVIRONMENTAL Footnote: ➀ Effective Bits is equal to: (SNR + Distortion) – 1.76 + Operating Temp. Range, Case ADS-942AMC ADS-942AME Storage Temperature Range Package Type Full Scale Amplitude 20 log Actual Input Amplitude 6.02 ➁ Same specification as In-Band Harmonics and Peak Harmonics. Weight ➂ Two-tone Intermodulation Distortion (IMD) conditions: fin = 100kHz, 240kHz, fs = 2MHz, –0.5dB 2 0 — +70 °C –40 — +85 °C –65 — +150 °C 32-pin, metal-sealed, ceramic TDIP 0.46 ounces (13 grams) ® ® ADS-942A TECHNICAL NOTES 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). 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). 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. 3. Full-Scale (Gain) Adjustment 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. 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). 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. 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. 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). 4. To confirm proper operation of the device, vary the precision reference voltage source to obtain the output coding listed in Table 3. Table 1. Input Connections CALIBRATION PROCEDURE 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. INPUT RANGE INPUT PIN TIE TOGETHER 0 +10V ±5V Pin 3 Pin 3 Pins 2 and 4 Pins 1 and 2 2. Zero Adjustments Table 2. Zero and Gain 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. Input Zero Adjust Range 0 to +10V ±5V 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). START CONVERT N Gain Adjust +½ LSB 35ns min., 50ns typ., 60 ns max +305µV +305µV N+1 35ns max.. Conversion Time 300ns typ., 325ns max. EOC 10ns typ. 15ns max. INTERNAL S/H 35ns typ. Hold 150ns max. Aquisition Time 350ns min. 30ns max. OUTPUT DATA DATA N VALID DATA N-1 VALID INVALID DATA 200ns max. 300ns min. Note: Scale is approximately 25ns per division. Figure 2. ADS-942A Timing Diagram 3 FS – 1½ LSB +9.999085V +4.999085V ® ® ADS-942A 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. 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. ZERO/OFFSET ADJUST 20kΩ –15V +15V 4.7µF + 0.1µF 4.7µF 0.1µF –5V + +15V 4.7µF + 0.1µF 4.7µF 0.1µF –15V 5 OFFSET ADJUST 10 + +5V 31 BIT 1 OUT(MSB) 30 BIT 1 OUT(MSB) DIGITAL 11 GROUND 29 BIT 2 OUT 28 BIT 3 OUT 14 27 BIT 4 OUT 26 BIT 5 OUT 25 BIT 6 OUT 12 24 BIT 7 OUT 23 BIT 8 OUT 22 BIT 9 OUT 6, 15 ANALOG GROUND 21 BIT 10 OUT 20 BIT 11 OUT 19 BIT 12 OUT 13 ADS-942A 18 BIT 13 OUT 17 BIT 14 OUT (LSB) GAIN ADJUST 7 OVERFLOW 16 EOC 0 to +10V 100Ω 3 ANALOG INPUT CODING SELECT 8 +5V 4 SIGNAL GROUND START CONVERT 32 1 +10V REF. OUT 0.1µF 4.7µF ENABLE 9 BIPOLAR 2 Figure 3. ADS-942A Connection Diagram (Unipolar Input) Table 3. Output Coding STRAIGHT BIN. UNIPOLAR SCALE +FS – 1 LSB +7/8 FS +3/4 FS +1/2 FS +1/4 FS +1/8 FS +1 LSB 0 INPUT VOLT. 0 TO +10V +9.999390 +8.750000 +7.500000 +5.000000 +2.500000 +1.250000 +0.000610 0.000000 COMP. BINARY LSB OUTPUT CODING MSB LSB MSB 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 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 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 OFF. BINARY COMP. OFF. BIN. TWO'S COMP. MSB 4 LSB INPUT VOLT. ±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 ® ® ADS-942A 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 Frequency (MHz) (fs = 2MHz, fin = 490kHz, Vin = –0.5dB, 16,384-point FFT) Figure 4. FFT Analysis of ADS-942A 5 0.9 1 ® ® ADS-942A 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 Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 1.11 MAX. (28.19) 1 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 ACCESSORIES OPERATING TEMP. RANGE ADS-942AMC 0 to +70°C ADS-942AME –40 to +85°C 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. ® ® ISO 9001 R DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com E-mail:[email protected] Data Sheet Fax Back: (508) 261-2857 E G I S T E R E D DS-0204B 10/96 DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 1-34-60-01-01 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.