® ® ADS-947 14-Bit, 10MHz Sampling A/D Converters PRELIMINARY PRODUCT DATA FEATURES • • • • • • • • • 14-bit resolution 10MHz minimum sampling rate No missing codes Ideal for both time and frequency-domain applications Excellent THD (–81dB) and SNR (76dB) Edge-triggered Small, 24-pin, ceramic DDIP or SMT Requires only +5V and –5.2V supplies Low-power, 2 Watts INPUT/OUTPUT CONNECTIONS GENERAL DESCRIPTION The ADS-947 is a 14-bit, 10MHz sampling A/D converter. This device accurately samples full-scale input signals up to Nyquist frequencies with no missing codes. Excellent differential nonlinearity error (DNL), signal-to-noise ratio (SNR), and total harmonic distortion (THD) make the ADS947 the ideal choice for both time-domain (CCD/FPA imaging, scanners, process control) and frequency-domain (radar, telecommunications, spectrum analysis) applications. The functionally complete ADS-947 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. The ADS-947 only requires the rising edge of a start convert pulse to operate. Requiring only +5V and –5.2V supplies, the ADS-947 typically dissipates just 2 Watts. The device is offered with a bipolar input range of ±2V. Models are available for use in either commercial (0 to +70°C) or extended (–40 to +100°C) PIN FUNCTION PIN FUNCTION 1 2 3 4 5 6 7 8 9 10 11 12 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 24 23 22 21 20 19 18 17 16 15 14 13 ANALOG GROUND OFFSET ADJUST +5V ANALOG SUPPLY ANALOG INPUT –5.2V SUPPLY ANALOG GROUND START CONVERT DATA VALID BIT 14 (LSB) BIT 13 DIGITAL GROUND +5V DIGITAL SUPPLY operating temperature ranges. A proprietary, auto-calibrating, error-correcting circuit allows the device to achieve specified performance over the extended temperature range. OFFSET ADJUST 23 BUFFER 16 BIT 14 (LSB) FLASH ADC 1 + POWER AND GROUNDING REF 22 +5V DIGITAL SUPPLY 13 –5.2V SUPPLY 20 ANALOG GROUND 19, 24 DIGITAL GROUND 14 DAC AMP START CONVERT 18 DATA VALID 17 FLASH ADC 2 REGISTER +5V ANALOG SUPPLY 15 BIT 13 12 BIT 12 11 BIT 11 OUTPUT REGISTER S/H DIGITAL CORRECTION LOGIC – REGISTER ANALOG INPUT 21 10 BIT 10 9 BIT 9 8 BIT 8 7 BIT 7 6 BIT 6 5 BIT 5 4 BIT 4 3 BIT 3 2 BIT 2 1 BIT 1 (MSB) TIMING AND CONTROL LOGIC Figure 1. ADS-947 Functional Block Diagram DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: (508) 339-3000, (800) 233-2765 Fax: (508) 339-6356 • Email: [email protected] • Internet: www.datel.com ® ® ADS-947 ABSOLUTE MAXIMUM RATINGS PARAMETERS +5V Supply (Pins 13, 22) –5.2V Supply (Pin 20) Digital Input (Pin 18) Analog Input (Pin 21) Lead Temperature (10 seconds) PHYSICAL/ENVIRONMENTAL LIMITS UNITS 0 to +6 0 to –5.5V –0.3 to +VDD +0.3 ±5 +300 Volts Volts Volts Volts °C PARAMETERS MIN. TYP. MAX. UNITS 0 –40 — — +70 +100 °C °C Operating Temp. Range, Case ADS-947MC, GC ADS-947ME, GE, QL Thermal Impedance θjc θca Storage Temperature Range Package Type Weight — 6 — °C/Watt — 23 — °C/Watt –65 — +150 °C 24-pin, metal-sealed, ceramic DDIP or SMT 0.46 ounces (13 grams) FUNCTIONAL SPECIFICATIONS (TA = +25°C, +VDD = +5V, –VDD = –5.2V, 10MHz sampling rate, and a minimum 3 minute warmup ➀ unless otherwise specified.) +25°C ANALOG INPUT Input Voltage Range ➁ Input Resistance Input Capacitance 0 to +70°C MIN. TYP. MAX. — — — ±2 250 6 — — 15 +2.0 — — — 10 — — — — 20 — — –0.95 — — — 14 MIN. –40 to +100°C TYP. MAX. — — — ±2 250 6 — — 15 — +0.8 +20 –20 — +2.0 — — — 10 — — — — 20 14 ±0.75 ±0.5 ±0.15 ±0.1 ±0.2 — — — +1.25 ±0.4 ±0.3 ±0.4 — — — –0.95 — — — 14 — — — –83 –78 –76 –76 –72 –71 — — — –81 –76 –74 72 72 71 MIN. TYP. MAX. UNITS — — — ±2 250 6 — — 15 Volts Ω pF — +0.8 +20 –20 — +2.0 — — — 10 — — — — 20 — +0.8 +20 –20 — Volts Volts µA µA ns 14 ±0.75 ±0.5 ±0.15 ±0.1 ±0.2 — — — +1.25 ±0.4 ±0.3 ±0.4 — — — –0.95 — — — 14 14 ±1 ±0.5 ±0.4 ±0.3 ±0.4 — — — +1.5 ±0.8 ±0.6 ±1.5 — Bits LSB LSB %FSR %FSR % Bits — — — –83 –78 –76 –75 –72 –71 — — — –79 –73 –71 –71 –68 –65 dB dB dB –74 –71 –69 — — — –81 –76 –74 –74 –71 –69 — — — –77 –72 –69 –70 –66 –63 dB dB dB 76 76 75 — — — 72 72 71 76 76 75 — — — 70 70 70 75 75 75 — — — dB dB dB 70 70 68 — 74 74 73 150 — — — — 70 70 68 — 74 74 73 150 — — — — 68 66 65 — 73 71 70 150 — — — — dB dB dB µVrms — –82 — — –82 — — –82 — dB — — — — — — 30 10 85 ±400 +5 2 — — — — — — — — — — — — 30 10 85 ±400 +5 2 — — — — — — — — — — — — 30 10 85 ±400 +5 2 — — — — — — MHz MHz dB V/µs ns ps rms DIGITAL INPUT Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Start Convert Positive Pulse Width ➂ STATIC PERFORMANCE Resolution Integral Nonlinearity (fin = 10kHz) Differential Nonlinearity (fin = 10kHz) Full Scale Absolute Accuracy Bipolar Zero Error (Tech Note 2) Gain Error (Tech Note 2) No Missing Codes (fin = 10kHz) DYNAMIC PERFORMANCE Peak Harmonics (–0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Total Harmonic Distortion (–0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Signal-to-Noise Ratio (w/o distortion, –0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Signal-to-Noise Ratio ➃ (& distortion, –0.5dB) dc to 1MHz 1MHz to 2.5MHz 2.5MHz to 5MHz Noise Two-tone Intermodulation Distortion (fin = 2.45MHz, 1.975MHz, fs = 10MHz, –0.5dB) Input Bandwidth (–3dB) Small Signal (–20dB input) Large Signal (–0.5dB input) Feedthrough Rejection (fin = 5MHz) Slew Rate Aperture Delay Time Aperture Uncertainty 2 ® ® ADS-947 +25°C DYNAMIC PERFORMANCE (Cont.) 0 to +70°C –40 to +100°C MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS — — 10 40 — — 45 100 — — — 10 40 — — 45 100 — — — 10 40 — — 45 100 — ns ns MHz +2.4 — — — — — — — — +0.4 –4 +4 +2.4 — — — +2.4 — — — — — — — — +0.4 –4 +4 Volts Volts mA mA +4.75 –4.75 +5.0 –5.2 +5.25 –5.45 +4.75 –4.75 +5.0 –5.2 +5.25 –5.45 +4.9 –4.9 +5.0 –5.2 +5.25 –5.45 Volts Volts — — — — +250 –200 2.0 — +260 –210 2.25 ±0.1 — — — — +250 –200 2.0 — +260 –210 2.25 ±0.1 — — — — +250 –200 2.0 — +260 –210 2.25 ±0.1 mA mA Watts %FSR/%V S/H Acquisition Time ( to ±0.003%FSR, 4V step) Overvoltage Recovery Time ➄ A/D Conversion Rate DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding — — — +0.4 — –4 — +4 Offset Binary POWER REQUIREMENTS Power Supply Ranges ➅ +5V Supply –5.2V Supply Power Supply Currents +5V Supply –5.2V Supply Power Dissipation Power Supply Rejection Footnotes: ➃ Effective bits is equal to: ➀ All power supplies should be on before applying a start convert pulse. All supplies and the clock (start convert pulses) must be present during warmup periods. The device must be continuously converting during this time. (SNR + Distortion) – 1.76 + 20 log Full Scale Amplitude Actual Input Amplitude 6.02 ➁ Contact DATEL for other input voltage ranges. ➂ A 10MHz clock with a 20ns positive pulse width is used for all production testing. See Timing Diagram, figure 4, for more details. ➄ This is the time required before the A/D output data is valid once the analog input is back within the specified range. This time is only guaranteed if the input does not exceed ±2.2V (S/H saturation voltage). ➅ The minimum supply voltages of +4.9V and –5.1V for ±VDD are required for –40°C operation only. The minimum limits are +4.75V and –4.95V when operating at +125°C TECHNICAL NOTES 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. 1. Obtaining fully specified performance from the ADS-947 requires careful attention to pc card layout and power supply decoupling. The device’s analog and digital ground systems are connected to each other internally. For optimal performance, tie all ground pins (14, 19 and 24) directly to a large analog ground plane beneath the package. 4. A passive bandpass filter is used at the input of the A/D for all production testing. Bypass all power supplies 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. 2kΩ GAIN ADJUST +5V 2. The ADS-947 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 Figures 2 and 3. 1.98kΩ SIGNAL INPUT To Pin 21 of ADS-947 50Ω When using this circuitry, or any similar offset and gain calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before gain. –5V Figure 2. Optional ADS-947 Gain Adjust Calibration Circuit 3 ® ® ADS-947 CALIBRATION PROCEDURE Any offset and/or gain calibration procedures should not be implemented until devices are fully warmed up. To avoid interaction, offset must be adjusted before gain. The ranges of adjustment for the circuits in Figures 2 and 3 are guaranteed to compensate for the ADS-947’s initial accuracy errors and may not be able to compensate for additional system errors. Gain Adjust Procedure 1. Apply +1.99963V to the ANALOG INPUT (pin 21). 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 input signal 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 can be accomplished by connecting LED’s to the digital outputs and adjusting 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. Table 1. Gain and Zero Adjust INPUT VOLTAGE RANGE Offset adjusting for the ADS-947 is normally accomplished at the point where the MSB is a 1 and all other output bits are 0’s and the LSB just changes from a 0 to a 1. This digital output transition ideally occurs when the applied analog input is +½ LSB (+122µV). ±2V Zero/Offset Adjust Procedure 1. Apply a train of pulses to the START CONVERT input (pin 18) so the converter is continuously converting. 2. Apply +122µV to the ANALOG INPUT (pin 21). 3. Adjust the offset potentiometer until the output bits are 10 0000 0000 0000 and the LSB flickers between 0 and 1. OFFSET BINARY MSB LSB +FS –1 LSB +3/4 FS +1/2 FS 0 –1/2 FS –3/4 FS –FS +1 LSB –FS +1.99976 +1.50000 +1.00000 0.00000 –1.00000 –1.50000 –1.99976 –2.00000 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 0.1µF 0.1µF 20 24 ADS-947 20k –5V START CONVERT INPUT VOLTAGE (±2V RANGE) 4.7µF 4.7µF + + 21 23 +1.99963V BIPOLAR SCALE 4.7µF + +5V ZERO/ OFFSET ADJUST +122µV +5V ➀ –5.2V ANALOG INPUT GAIN ADJUST +FS –1½ LSB Table 2. Output Coding for Bipolar Operation Gain adjusting is accomplished when all bits are 1’s and the LSB just changes from a 1 to a 0. This transition ideally occurs when the analog input is at +full scale minus 1½ LSB's (+1.99963V). 19 ZERO ADJUST +½ LSB 18 0.1µF 22, 13 14 1 2 3 4 5 6 7 8 9 10 11 12 15 16 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 (LSB) DATA VALID ➀ A single +5V supply should be used for both the +5V analog and +5V digital. If separate supplies are used, the difference between the two cannot exceed 100mV. Figure 3. Typical ADS-947 Connection Diagram 4 ® ® ADS-947 THERMAL REQUIREMENTS All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70°C and –40 to +100°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. 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. 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 AN8, "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. N START CONVERT N+1 20ns typ. 10ns typ. Acquisition Time INTERNAL S/H Hold 65ns typ. (61ns min., 68ns max.) INTERNAL EOC Conversion Time 70ns typ. 35ns typ. 25ns typ. (22ns min., 28ns max.) 15ns DATA VALID DATA N-1 VALID DATA N VALID 40ns typ. (±5ns) 40ns typ. (±5ns) 40ns max. OUTPUT DATA 50ns typ. DATA N-1 VALID 50ns typ. (±5ns) DATA N VALID INVALID DATA Notes: 1. Scale is approximately 5ns per division. Sampling rate = 10MHz. 2. The start convert pulse must be between 20 and 50ns wide or between 80 and 100ns wide (when sampling at 10MHz) to ensure proper operation. For sampling rates less than 10MHz, the start pulse can be wider than 85nsec, however a minimum pulse width low of 15nsec should be maintained. A 10MHz clock with a 20nsec positive pulse width is used for all production testing. Figure 4. ADS-947 Timing Diagram 5 ® ADS-947 Figure 5. FFT Analysis of ADS-947 (fs = 8MHz, fin = 3.85MHz, Vin = –0.5dB, 16,384 point FFT) Figure 6. ADS-947 Histogram and Differential Nonlinearity 6 ® ANA. IN SG10 SG3 SG2 SG1 P4 P2 26 24 22 20 18 16 14 12 10 8 6 4 2 25 23 21 19 17 15 13 11 9 7 5 3 1 ANA. IN 20µH L7 20µH L6 20µH L5 20µH L4 20µH L3 20µH L2 20µH L1 + + C8 0.01µF C9 0.01µF C1 2.2µF C2 2.2µF + C10 0.01µF C11 0.01µF C12 0.01µF C3 2.2µF C4 2.2µF C5 2.2µF + 2.2µF 0.01µF C14 0.01µF 2.2µF C7 C13 R2 SG5 –5V +5VA +15V –15V –5VA +5V 5 +15V 10 12 11 13 0.1µF (Optional) U6 5 4 13 12 C15 11 U5 6 7 +5V 24 23 22 21 20 19 18 17 16 15 14 13 C23 HCT7474 7 ADS-947 AGND BIT1 OFFSET BIT2 +5VA BIT3 AIN BIT4 –5.2V BIT5 AGND BIT6 START BIT7 DATA VALID BIT8 BIT14 BIT9 BIT13 BIT10 DGND BIT11 +5VD BIT12 U1 1 2 3 4 5 6 7 8 9 10 11 12 3.2k 2.2µF 14 4 JPR1 PR 5 2 D U6 Q 6 3 1 2 3 CK Q 1 R3 CLR 0.1µF C24 + START CONVERT 15pF C25 +5VA 8 SG9 14 –5.2V 2.2µF C27 74HCT86 0.1µF 7 GND U5 14 +5VF ANA. IN SG4 0.1µF C26 X1 10MHz CRYSTAL +5VF +5VF 10 9 P3 U5 U5 + 0.1µF 2.2µF C16 C22 3 2 3 4 5 6 7 8 9 11 2 3 4 5 6 7 8 9 11 74HCT573 C21 74HCT573 19 18 17 16 15 14 13 12 1 +5VF 19 18 17 16 15 14 13 12 1 2.2µF Q1 1D 2D Q2 Q3 3D 4D Q4 U2 Q5 5D 6D Q6 Q7 7D Q8 8D OE CE 10 20 10 C17 0.1µF Q1 1D 2D Q2 Q3 3D 4D Q4 5D U3 Q5 6D Q6 Q7 7D Q8 8D OE CE 20 + +5VF 2. CLOSE SG1-SG3, SG9, SG10. ALL RESISTORS ARE IN OHMS. C1 - C7 ARE 20V. 1. UNLESS OTHERWISE SPECIFIED ALL CAPACITORS ARE 50V. NOTES: 74HCT86 8 74HCT86 2 1 START CONVERT Figure 7. ADS-947 Evaluation Board Schematic (ADS-B947) HCT7474 9 Q 8 SPARE GATES 0.1µF C19 (Optional) -15V C20 PR D CK CLR 2 R1 C18 0.1µF (Optional) SG6 20k –15V SG8 CLC402 HI2541 10 +5VA OFFSET ADJUST –5VA SG7 6 U4 11 +15V +5VF + (Optional) 4 – +5VF C6 + + 7 + OPTION + 2 3 JPR2 1 CE B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 TRIG 2 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 P1 1 33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 ® ® ADS-947 ® ® ADS-947 MECHANICAL DIMENSIONS INCHES (mm) 1.31 MAX. (33.27) 24-Pin DDIP Versions 24 Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) 13 0.80 MAX. (20.32) ADS-947MC ADS-947ME 1 Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 12 0.100 TYP. (2.540) 1.100 (27.940) 0.235 MAX. (5.969) PIN 1 INDEX 0.200 MAX. (5.080) 0.010 (0.254) 0.190 MAX. (4.826) 0.100 (2.540) 0.040 (1.016) 0.018 ±0.002 (0.457) +0.002 –0.001 0.600 ±0.010 (15.240) SEATING PLANE 0.025 (0.635) 0.100 (2.540) 1.31 MAX. (33.02) 24-Pin Surface Mount Versions Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) 13 24 0.80 MAX. (20.32) ADS-947GC ADS-947GE 1 0.190 MAX. (4.826) Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 12 0.020 TYP. (0.508) 0.060 TYP. (1.524) 0.130 TYP. (3.302) PIN 1 INDEX 0.100 (2.540) 0.100 TYP. (2.540) 0.020 (0.508) 0.015 (0.381) MAX. radius for any pin 0.010 TYP. (0.254) 0.040 (1.016) ORDERING INFORMATION MODEL OPERATING TEMP. RANGE 24-PIN PACKAGE ADS-947MC ADS-947ME ADS-947ME-QL ADS-947GC ADS-947GE 0 to +70°C –40 to +100°C –40 to +100°C 0 to +70°C –40 to +100°C DDIP DDIP DDIP SMT SMT ACCESSORIES ADS-B947 HS-24 Evaluation Board (without ADS-947) Heat Sink for all ADS-947 DDIP models Receptacles for PC board mounting can be ordered through AMP, Inc., Part # 3-331272-8 (Component Lead Socket), 24 required. INNOVATION and EXCELLENCE ISO 9001 DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com Email: [email protected] Data Sheet Fax Back: (508) 261-2857 DS-0346 Preliminary 10/01 DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01 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.