ADS-927GM

® ® ADS-927 14-Bit, 1MHz, Low-Power Sampling A/D Converters FEATURES • • • • • • • • 14-bit resolution 1MHz sampling rate Functionally complete No missing codes Small 24-pin DDIP or SMT package Low power, 1.9 Watts maximum Operates from ±15V or ±12V supplies Bipolar ±5V input range GENERAL DESCRIPTION The ADS-927 is a high-performance, 14-bit, 1MHz sampling A/D converter. This device samples input signals up to Nyquist frequencies with no missing codes. The ADS-927 features outstanding dynamic performance including a THD of –80dB. Housed in a small 24-pin DDIP or SMT (gull-wing) package, the functionally complete ADS-927 contains a fast-settling sample-hold amplifier, a subranging (two-pass) A/D converter, a precise voltage reference, timing/control logic, and errorcorrection circuitry. Digital input and output levels are TTL. Requiring ±15V (or ±12V) and +5V supplies, the ADS-927 dissipates only 1.95W (1.65W for ±12V), maximum. The unit is offered with a bipolar input (–5V to +5V). Models are available for use in either commercial (0 to +70°C) or military (–55 to +125°C) operating temperature ranges. Applications include radar, sonar, spectrum analysis, and graphic/medical imaging. PIN 1 2 3 4 5 6 7 8 9 10 11 12 INPUT/OUTPUT CONNECTIONS FUNCTION BIT 14 (LSB) BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 PIN 24 23 22 21 20 19 18 17 16 15 14 13 FUNCTION –12V/–15V SUPPLY ANALOG GROUND +12V/+15V SUPPLY +10V REFERENCE OUT ANALOG INPUT ANALOG GROUND BIT 1 (MSB) BIT 2 START CONVERT EOC DIGITAL GROUND +5V SUPPLY DAC 18 BIT 1 (MSB) 17 BIT 2 +10V REF. OUT 21 S2 FLASH ADC S/H ANALOG INPUT 20 – REGISTER + S1 BUFFER REGISTER REF DIGITAL CORRECTION LOGIC 12 BIT 3 11 BIT 4 10 BIT 5 9 8 7 6 5 4 3 2 1 BIT 6 BIT 7 BIT 8 BIT 9 BIT 10 BIT 11 BIT 12 BIT 13 BIT 14 (LSB) START CONVERT 16 TIMING AND CONTROL LOGIC EOC 15 13 +5V SUPPLY 14 DIGITAL GROUND 22 +12V/+15V SUPPLY 19, 23 ANALOG GROUND 24 –12V/–15V SUPPLY Figure 1. ADS-927 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-927 ABSOLUTE MAXIMUM RATINGS PARAMETERS +12V/+15V Supply (Pin 22) –12V/–15V Supply (pin 24) +5V Supply (Pin 13) Digital Input (Pin 16) Analog Input (Pin 20) Lead Temperature (10 seconds) LIMITS 0 to +16 0 to –16 0 to +6 –0.3 to +VDD +0.3 ±15 +300 UNITS Volts Volts Volts Volts Volts °C PHYSICAL/ENVIRONMENTAL PARAMETERS Operating Temp. Range, Case ADS-927MC, GC ADS-927MM, GM, 883 Thermal Impedance θjc θca Storage Temperature Package Type Weight MIN. 0 –55 TYP. — — MAX. +70 +125 UNITS °C °C 6 °C/Watt 24 °C/Watt –65 — +150 °C 24-pin, metal-sealed, ceramic DDIP or SMT 0.42 ounces (12 grams) FUNCTIONAL SPECIFICATIONS (TA = +25°C, ±VCC = ±15V (or ±12V), +VDD = +5V, 1MHz sampling rate, and a minimum 1 minute warmup Œ unless otherwise specified.) +25°C ANALOG INPUT Input Voltage Range  Input Resistance Input Capacitance DIGITAL INPUT Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Start Convert Positive Pulse Width Ž STATIC PERFORMANCE Resolution Integral Nonlinearity (fin = 10kHz) Differential Nonlinearity (fin = 10kHz) 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) DYNAMIC PERFORMANCE Peak Harmonics (–0.5dB) dc to 100kHz 100kHz to 500kHz Total Harmonic Distortion (–0.5dB) dc to 100kHz 100kHz to 500kHz Signal-to-Noise Ratio (w/o distortion, –0.5dB) dc to 100kHz 100kHz to 500kHz Signal-to-Noise Ratio  (& distortion, –0.5dB) dc to 100kHz 100kHz to 500kHz Two-Tone Intermodulation Distortion (fin = 100kHz, 240kHz, fs = 1MHz, –0.5dB) Noise 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  A/D Conversion Rate — — — — 77 75 76 73 — — — — — — — — 335 — 1 –91 –82 –90 –80 79 78 78 76 –87 350 7 5 84 ±60 ±20 5 390 400 — –83 –78 –81 –76 — — — — — — — — — — — — 445 1000 — — — — — 74 74 73 73 — — — — — — — — 335 — 1 –90 –82 –89 –80 78 78 77 76 –86 350 7 5 84 ±60 ±20 5 390 400 — — –78 — –76 — — — — — — — — — — — — 445 1000 — — — — — 73 73 71 71 — — — — — — — — 335 — 1 –88 –80 –87 –79 77 76 76 75 –85 350 7 5 84 ±60 ±20 5 390 400 — — –77 — –74 — — — — — — — — — — — — 445 1000 — dB dB dB dB dB dB dB dB dB µVrms MHz MHz dB V/µs ns ps rms ns ns MHz — — — — — — — 14 14 ±0.5 ±0.5 ±0.08 ±0.05 ±0.05 ±0.1 — — — ±0.95 ±0.15 ±0.1 ±0.1 ±0.15 — — — — — — — — 14 14 ±0.75 ±0.5 ±0.15 ±0.1 ±0.1 ±0.15 — — — ±0.95 ±0.25 ±0.25 ±0.25 ±0.25 — — — — — — — — 14 14 ±1.5 ±0.75 ±0.3 ±0.15 ±0.25 ±0.25 — — — ±0.99 ±0.5 ±0.3 ±0.4 ±0.4 — Bits LSB LSB %FSR %FSR %FSR % Bits +2.0 — — — 175 — — — — 200 — +0.8 +20 –20 225 +2.0 — — — 175 — — — — 200 — +0.8 +20 –20 225 +2.0 — — — 175 — — — — 200 — +0.8 +20 –20 225 Volts Volts µA µA ns MIN. — — — TYP. ±5 1 7 MAX. — — 15 MIN. — — — 0 to +70°C TYP. ±5 1 7 MAX. — — 15 MIN. — — — –55 to +125°C TYP. ±5 1 7 MAX. — — 15 UNITS Volts kΩ pF 2 ® ® ADS-927 +25°C ANALOG OUTPUT Internal Reference Voltage Drift External Current DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Delay, Falling Edge of EOC to Output Data Valid Output Coding POWER REQUIREMENTS, ±15V Power Supply Ranges +15V Supply –15V Supply +5V Supply Power Supply Currents +15V Supply –15V Supply +5V Supply Power Dissipation Power Supply Rejection POWER REQUIREMENTS, ±12V Power Supply Ranges +12V Supply –12V Supply +5V Supply Power Supply Currents +12V Supply –12V Supply +5V Supply Power Dissipation Power Supply Rejection +11.5 –11.5 +4.75 — — — — — +12.0 –12.0 +5.0 +42 –25 +71 1.4 — +12.5 –12.5 +5.25 +65 –45 +80 1.65 ±0.02 +11.5 –11.5 +4.75 — — — — — +12.0 –12.0 +5.0 +42 –25 +71 1.4 — +12.5 –12.5 +5.25 +65 –45 +80 1.65 ±0.02 +11.5 –11.5 +4.75 — — — — — +12.0 –12.0 +5.0 +42 –25 +71 1.4 — +12.5 –12.5 +5.25 +65 –45 +80 1.65 ±0.02 Volts Volts Volts mA mA mA Watts %FSR/%V +14.5 –14.5 +4.75 — — — — — +15.0 –15.0 +5.0 +43 –25 +71 1.6 — +15.5 –15.5 +5.25 +65 –45 +80 1.95 ±0.02 +14.5 –14.5 +4.75 — — — — — +15.0 –15.0 +5.0 +43 –25 +71 1.6 — +15.5 –15.5 +5.25 +65 –45 +80 1.95 ±0.02 +14.5 –14.5 +4.75 — — — — — +15.0 –15.0 +5.0 +43 –25 +71 1.6 — +15.5 –15.5 +5.25 +65 –45 +80 1.95 ±0.02 Volts Volts Volts mA mA mA Watts %FSR/%V +2.4 — — — — — — — — — — +0.4 –4 +4 35 +2.4 — — — — — — — — — — +0.4 –4 +4 35 Offset Binary +2.4 — — — — — — — — — — +0.4 –4 +4 35 Volts Volts mA mA ns MIN. +9.95 — — TYP. +10.0 ±5 — MAX. +10.05 — 1.5 MIN. +9.95 — — 0 to +70°C TYP. +10.0 ±5 — MAX. +10.05 — 1.5 MIN. +9.95 — — –55 to +125°C TYP. +10.0 ±5 — MAX. +10.05 — 1.5 UNITS Volts ppm/°C mA Footnotes: Œ All power supplies must 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. There is a slight degradation in performance when using ±12V supplies.  See Ordering Information for 0 to +10V input range. Contact DATEL for availability of other input voltage ranges. Ž A 1MHz clock with a 200ns wide start convert pulse is used for all production testing. For applications requiring less than a 1MHz sampling rate, wider start convert pulses can be used. See Timing Diagram for more details.  Effective bits is equal to: (SNR + Distortion) – 1.76 + 20 log 6.02 Full Scale Amplitude Actual Input Amplitude  This is the time required before the A/D output data is valid after the analog input is back within the specified range. TECHNICAL NOTES 1. Obtaining fully specified performance from the ADS-927 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 23) directly to a large analog ground plane below the package. Bypass all power supplies and the REFERENCE OUTPUT (pin 21) 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. If the user-installed offset and gain adjusting circuit in Figure 2 is used, also locate it as close to the ADS-927 as possible. 2. The ADS-927 achieves its specified accuracies without the 3 need for external calibration. If required, the device's small initial offset and gain errors can be reduced to zero using the input circuit of Figure 2. When using this circuit, or any similar offset and gain-calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before gain. 3. When operating the ADS-927 from ±12V supplies, do not drive external circuitry with the REFERENCE OUTPUT. The reference's accuracy and drift specifications may not be met, and loading the circuit may cause accuracy errors within the converter. 4. Applying a start convert pulse while a conversion is in progress (EOC = logic "1") initiates a new and inaccurate conversion cycle. Data for the interrupted and subsequent conversions will be invalid. ® ® ADS-927 CALIBRATION PROCEDURE (Refer to Figures 2 and 3) 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 circuit of Figure 2 are guaranteed to compensate for the ADS-927's initial accuracy errors and may not be able to compensate for additional system errors. All fixed resistors in Figure 2 should be metal-film types, and multiturn potentiometers should have TCR’s of 100ppm/°C or less to minimize drift with temperature. 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. For the ADS-927, offset adjusting 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 +½LSB (+305µV). 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 (+4.999085V). +15V ZERO/ OFFSET ADJUST 20kΩ 1.2MΩ 2kΩ Zero/Offset Adjust Procedure 1. Apply a train of pulses to the START CONVERT input (pin 16) so the converter is continuously converting. If using LED's on the outputs, a 200kHz conversion rate will reduce flicker. 2. Apply +305µV to the ANALOG INPUT (pin 20). 3. Adjust the offset potentiometer until the output bits are a 1 and all 0's and the LSB flickers between 0 and 1. Gain Adjust Procedure 1. Apply +4.999085V to the ANALOG INPUT (pin 20). 2. Adjust the gain potentiometer until the output bits are all 1's and the LSB flickers between 1 and 0. Table 1. Zero and Gain Adjust INPUT VOLTAGE RANGE ±5V ZERO ADJUST +½ LSB +305µV GAIN ADJUST +FS –1½ LSB +4.999085V Table 2. Output Coding OUTPUT CODING MSB LSB 11 11 11 10 01 00 00 00 1111 1000 0000 0000 0000 1000 0000 0000 1111 0000 0000 0000 0000 0000 0000 0000 1111 0000 0000 0000 0000 0000 0001 0000 INPUT RANGE ±5V +4.99939 +3.75000 +2.50000 0.00000 –2.50000 –3.75000 –4.99939 –5.00000 BIPOLAR SCALE +FS –1 LSB +3/4 FS +1/2FS 0 –1/2FS –3/4FS –FS +1 LSB –FS –15V GAIN ADJUST +15V 1.98kΩ 50Ω To Pin 20 of ADS-927 SIGNAL INPUT Coding is offset binary; 1LSB = 610µV. –15V Figure 2. ADS-927 Calibration Circuit 18 BIT 1 (MSB) +5V 4.7µF + 0.1µF 14 DIGITAL GROUND 13 17 BIT 2 12 BIT 3 11 BIT 4 10 BIT 5 9 BIT 6 8 BIT 7 7 BIT 8 6 BIT 9 5 BIT 10 4 BIT 11 3 BIT 12 2 BIT 13 1 BIT 14 (LSB) 15 EOC START 16 CONVERT –12V/–15V 4.7µF + 4.7µF + +12V/+15V 0 to +10V 0.1µF 24 ADS-927 ANALOG GROUND 19, 23 0.1µF 22 ANALOG 20 INPUT 21 +10V REF. OUT 0.1µF + 4.7µF Figure 3. Typical ADS-927 Connection Diagram 4 ® ® ADS-927 THERMAL REQUIREMENTS 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 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. 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 AN-8, "Heat Sinks for DIP Data Converters", or contact DATEL directly, for additional information. N START CONVERT 10ns typ. INTERNAL S/H 200ns ±25ns N+1 Hold 610ns typ. 10ns typ. Acquisition Time 390ns ±55ns 70ns ±10ns Conversion Time EOC 480ns ±20ns 35ns max. 150ns max. OUTPUT DATA Data (N – 1) Valid Invalid Data Notes: 1. fs = 1MHz. 2. The ADS-927 is a pulse-triggered device. Its internal operations are triggered by both the rising and falling edges of the start convert pulse. When sampling at 1MHz, the start pulse must be between 175 and 225nsec wide. For lower sampling rates, wider start pulses may be used, however, a minimum pulse width low of 50nsec must be maintained. Data N Valid (850ns min.) Figure 4. ADS-927 Timing Diagram 5 74LS86 9 10 U4 +5V COG 12 13 74ALS534 20 74LS86 1D 1Q 2Q 3Q 4Q U2 5D 5Q 6Q 7Q 8Q OC 10 +5V 1 19 16 B7 15 B6 6D 7D 8D CLK 12 B5 9 B4 6 B3 28 26 24 22 20 5 B2 30 2D 3D 4D B1 32 4 7 3 2 33 31 29 27 25 23 21 19 U4 11 8 ADS-927 +15V OFFSET ADJ R3 1.2M 5% R5 2K +15V C2 15pF C16 0.1MF R2 20K 0.1% C1 0.1MF -15V + P4 50 2 14 C3 0.1MF +5V 13 6 8 GAIN ADJ .1% + 3 + 4 13 12 +5V 14 DGND B4 B5 B6 B7 U1 B9 B10 B11 B12 B13 2 B14 1 3 4 5 6 B8 7 8 3 4 7 8 13 14 17 18 11 9 74ALS534 20 1D 2D 3D 4D U3 5D 6D 7D 8D CLK 5Q 6Q 7Q 8Q OC 10 1Q 2Q 3Q 4Q 2 5 6 9 12 15 16 19 1 10 EOC' STRTCONV B2 B1 AGND INPUT +10VREF +15V AGND -15V 11 15 16 17 18 B3 11 AD845 18 17 ANALOG INPUT U5 C7 0.1MF C8 2.2MF R1 R4 1.98K C4 7 2.2MF + P1 +5V C6 2.2MF -15V C5 0.1 MF 2 1 C17 0.1MF P2 B8 B9 B10 B11 B12 B13 B14 18 16 14 12 10 8 6 4 N/C N/C 2 34 17 15 13 11 9 7 5 3 1 4 3 6 5 + C13 0.1MF + 6 C10 0.1MF C9 2.2MF 19 20 21 +15V C11 2.2MF +15V -15V 24 C12 0.1MF ADS-926/927 23 22 8 7 + 10 -15V 9 12 11 14 13 16 15 18 17 20 19 22 +5V C15 0.1MF 21 24 23 25 P3 14 START CONVERT 3 U4 7 74LS86 2 1 C14 2.2MF 4 5 U4 74LS86 6 26 ® SG1 Figure 5. ADS-927 Evaluation Board Schematic ® ® ® ADS-927 0 –10 Amplitude Relative to Full Scale (dB) –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 –120 –130 –140 –150 0 50 100 150 200 250 300 350 400 450 500 Frequency (kHz) (fs = 1MHz, fin = 480kHz, Vin = –0.5dB, 16,384-point FFT) Figure 6. ADS-927 FFT Analysis +0.71 DNL (LSB's) 0 Number of Occurrences –0.49 0 Digital Output Code 16,384 0 Digital Output Code 16,384 Figure 7. ADS-927 Histogram and Differential Nonlinearity 7 ® ® ADS-927 MECHANICAL DIMENSIONS INCHES (mm) 1.31 MAX. (33.27) 24-Pin DDIP Versions ADS-927MC ADS-927MM ADS-927/883 ADS-917MC ADS-917MM 0.235 MAX. (5.969) 24 13 0.80 MAX. (20.32) Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 1 12 0.100 TYP. (2.540) 1.100 (27.940) PIN 1 INDEX 0.200 MAX. (5.080) 0.010 (0.254) 0.190 MAX. (4.826) 0.018 ±0.002 (0.457) 0.100 (2.540) 0.040 (1.016) +0.002 –0.001 SEATING PLANE 0.025 (0.635) 0.600 ±0.010 (15.240) 0.100 (2.540) 1.31 MAX. (33.02) 24-Pin Surface Mount Versions ADS-927GC ADS-927GM ADS-917GC ADS-917GM 24 13 Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) 0.80 MAX. (20.32) Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 1 12 0.190 MAX. (4.826) 0.020 TYP. (0.508) PIN 1 INDEX 0.060 TYP. (1.524) 0.130 TYP. (3.302) 0.015 (0.381) MAX. radius for any pin 0.100 (2.540) 0.100 TYP. (2.540) 0.040 (1.016) 0.020 (0.508) 0.010 TYP. (0.254) ORDERING INFORMATION MODEL NUMBER ADS-927MC ADS-927MM ADS-927/883 ADS-927GC ADS-927GM ADS-917MC ADS-917MM ADS-917GC ADS-917GM OPERATING TEMP. RANGE 0 to +70°C –55 to +125°C –55 to +125°C 0 to +70°C –55 to +125°C 0 to +70°C –55 to +125°C 0 to +70°C –55 to +125°C ANALOG INPUT Bipolar (±5V) Bipolar (±5V) Bipolar (±5V) Bipolar (±5V) Bipolar (±5V) Unipolar (0 to +10V)* Unipolar (0 to +10V)* Unipolar (0 to +10V)* Unipolar (0 to +10V)* ACCESSORIES ADS-B926/927 HS-24 Evaluation Board (without ADS-927) Heat Sinks for all ADS-917/927 DDIP models Receptacles for PC board mounting can be ordered through AMP Inc. Part #3-331272-8 (Component Lead Socket), 24 required. For MIL-STD-883 product specifications, contact DATEL. * For information, see ADS-917 data sheet. ® ® ISO 9001 R E G I S T E R E D DS-0246E 11/96 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:sales@datel.com Data Sheet Fax Back: (508) 261-2857 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.