ADS-945 14-Bit, 10MHz Sampling Converters FEATURES 14-b

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ADS-945 14-Bit, 10MHz Sampling Converters FEATURES 14-b

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ADS-945
14-Bit, 10MHz Sampling Converters
FEATURES
14-bit resolution 10MHz minimum throughput Functionally complete missing codes power, 4.2W Excellent dynamic performance Internally clamped input Edge triggered compatible module Very profile
INPUT/OUTPUT CONNECTIONS
10-11 15-17 19-25
FUNCTION
ANALOG GROUND ANALOG INPUT ANALOG GROUND +10V REFERENCE ANALOG GROUND GAIN ADJUST CONNECT -15V SUPPLY ANALOG GROUND +15V SUPPLY ANALOG GROUND OFFSET ADJUST ANALOG GROUND MISSING DIGITAL GROUND DIGITAL GROUND STATUS STATUS DIGITAL GROUND START CONVERT OVERFLOW OUTPUT ENABLE (OE) DIGITAL GROUND O.S. DIGITAL GROUND DIGITAL GROUND
70-76 64-68 58-60
FUNCTION
ANALOG GROUND ANALOG SUPPLY ANALOG GROUND -5.2V ANALOG SUPPLY ANALOG GROUND CONNECT DIGITAL GROUND -5.2V DIGITAL SUPPLY CONNECT DIGITAL SUPPLY DIGITAL GROUND (MSB) (LSB) DIGITAL GROUND
GENERAL DESCRIPTION
low-cost ADS-945 high-performance, 14-bit, 10MHz sampling converter. This device accurately samples full-scale input signals Nyquist frequencies with missing codes. dynamic performance ADS-945 been optimized achieve -82dB 79dB. Packaged module, functionally complete ADS-945 contains fast-settling sample/hold amplifier, subranging (two-pass) converter, precise voltage reference, timing/control logic, three-state outputs, error-correction circuitry. Digital inputs outputs compatible (except pins which ECL). Requiring ±15V, -5.2V supplies, ADS-945 typically dissipates 4.2W. unit offered with bipolar input range ±1.25V. Models available either commercial +70°C) military (-55 +125°C) operating temperature ranges. Typical applications include radar signal analysis, medical/graphic imaging, spectrum analysis.
Refer Timing Diagram notes
OVERFLOW BUFFER (MSB) ANALOG INPUT FLASH DIGITAL CORRECTION LOGIC 3-STATE OUTPUT REGISTER (LSB) START CONVERT STATUS STATUS TIMING CONTROL LOGIC OUTPUT ENABLE MISSING 10,11,56 CONNECT -15V SUPPLY O.S. +15V SUPPLY 27,28,31,35,37-39,54,58-60 DIGITAL GROUND CONNECT DIGITAL SUPPLY -5.2V DIGITAL SUPPLY
GAIN ADJUST REF. CASE 1,2,3,5,6,8,13,15,17, 19-25,62,64-68,70-76 ANALOG GROUND OFFSET ADJUST AGND
GAIN CIRCUIT
DGND OFFSET CIRCUIT FLASH
Figure ADS-945 Functional Block Diagram
DATEL, Inc., Cabot Boulevard, Mansfield, 02048-1151 (U.S.A.) Tel: (508) 339-3000 Fax: (508) 339-6356 immediate assistance: (800) 233-2765
ADS-945
ABSOLUTE MAXIMUM RATINGS
PARAMETERS +15V Supply (Pins -15V Supply (Pin Supply (Pins Supply (Pin Digital Input (Pin Analog Input (Pin Lead Temperature seconds) LIMITS -0.3 +VDD +0.3 +300 UNITS Volts Volts Volts Volts Volts Volts
PHYSICAL/ENVIRONMENTAL
PARAMETERS Operating Temp. Range, Case ADS-945 ADS-945EX Thermal Impedance Storage Temperature Range Package Type Weight MIN. TYP. MAX. +125 +150 UNITS °C/Watt °C/Watt
module grams)
FUNCTIONAL SPECIFICATIONS
+25°C, ±VCC ±15V, +VDD +5V, -5.2V, 10MHz sampling rate, minimum minute warmup unless otherwise specified.) +25°C ANALOG INPUT Input Voltage Range Input Resistance Input Capacitance Input Bias Current DIGITAL INPUT Logic Levels Logic Logic Logic Loading Logic Loading Start Convert Positive Pulse Width STATIC PERFORMANCE Resolution Integral Nonlinearity (fin 10kHz) Differential Nonlinearity (fin 10kHz) Full Scale Absolute Accuracy Bipolar Offset Error (Tech Note Gain Error (Tech Note Missing Codes (fin 10kHz) DYNAMIC PERFORMANCE Peak Harmonics (-0.5dB) 1mHz 1MHz 2.5MHz 2.5MHz 5MHz Total Harmonic Distortion (-0.5dB) 1MHz 1MHz 2.5MHz 2.5MHz 5MHz Signal-to-Noise Ratio (w/o distortion, -0.5dB) 1MHz 100kHz 2.5MHz 2.5MHz 5MHz Signal-to-Noise Ratio distortion, -0.5dB) 100kHz 1MHz 2.5MHz 2.5MHz 5MHz Noise Two-tone Intermodulation Distortion (fin 1.975MHz, 2.45MHz, 10MHz, -0.5dB) Input Bandwidth (-3dB) Small Signal (-20dB input) Large Signal (-0.dB input) Feedthrough Rejection (fin 4.85MHz) Slew Rate Aperture Delay Time Aperture Uncertainty ±850 ±850 ±850 µVrms V/µs ±0.5 ±0.5 ±0.2 ±0.15 ±0.1 ±0.75 ±0.4 ±0.25 ±0.2 ±0.75 ±0.5 ±0.3 ±0.25 ±0.2 ±0.75 ±0.5 ±0.5 ±0.4 -0.95 ±0.75 ±0.75 ±0.3 ±0.3 ±0.3 +1.5 ±0.7 ±0.7 ±0.7 Bits %FSR %FSR Bits +2.0 +0.8 +2.0 +0.8 +2.0 +0.8 Volts Volts MIN. TYP. ±1.25 MAX. MIN. +70°C TYP. ±1.25 MAX. MIN. +125°C TYP. ±1.25 MAX. UNITS Volts
ADS-945
+25°C DYNAMIC PERFORMANCE cont. Acquisition Time ±0.003%FSR, 2.5V step) Overvoltage Recovery Time Conversion Rate ANALOG OUTPUT Reference Output Reference Temperature Drift Reference Load Curent DIGITAL OUTPUTS Logic Levels Logic Logic Logic Loading Logic Loading Delay, Falling Edge Output Data Valid Delay, Edge ENABLE Output Data Valid/Invalid Output Coding POWER REQUIREMENTS Power Supply Ranges +15V Supply -15V Supply Supply -5.2V Supply Power Supply Currents +15V Supply -15V Supply Supply -5.2V Supply Power Dissipation Power Supply Rejection +14.25 -14.25 +4.75 -4.95 +15.0 -15.0 +5.0 -5.2 +140 -430 +15.75 -15.75 +5.25 -5.45 +160 -460 ±0.04 +14.25 -14.25 +4.75 -4.95 +15.0 -15.0 +5.0 -5.2 +140 -430 +15.75 -15.75 +5.25 -5.45 +160 -460 ±0.04 +14.25 -14.25 +4.75 -4.95 +15.0 -15.0 +5.0 -5.2 +140 -430 +15.75 -15.75 +5.25 -5.45 +160 -460 ±0.04 Volts Volts Volts Volts Watts %FSR/%V +2.7 +0.5 -0.4 +2.7 +0.5 -0.4 +2.7 +0.5 -0.4 Volts Volts +9.99 +10.01 +9.99 +10.01 +9.99 +10.01 Volts ppm/°C MIN. TYP. MAX. MIN. +70°C TYP. MAX. MIN. +125°C TYP. MAX. UNITS
Complementary Offset Binary
Footnotes:
power supplies should before applying start convert pulse. supplies clock (start convert pulses) must present during warmup periods. device must continuously converting during this time. input ADS-945 internally clamped ±2.3V. 50ns wide start convert pulse used production testing. applications requiring less than 10MHz sampling rate, wider start convert used. Effective bits equal
(SNR Distortion) 1.76 6.02 Full Scale Amplitude Actual Input Amplitude
This time required before output valid after analog input back within range. Typical -5.2V current drain breakdowns follows: +5VAnalog +100mA +5VDigital +40mA +5VTotal +140mA -5.2VAnalog -210mA -5.2VDigital -220mA -5.2VTotal -430mA
TECHNICAL NOTES
Obtaining fully specified performance from ADS-945 requires careful attention pc-card layout power supply decoupling. device's analog digital ground systems connected each other internally. optimal performance, ground pins directly large analog ground plane beneath package. Bypass power supplies ground with 10µF tantalum capacitors parallel with 0.1µF ceramic capacitors. bypass capacitors should located close unit possible. ADS-945 achieves specified accuracies without need external calibration. required, device's small initial offset gain errors reduced zero using
adjustment circuitry shown Figure typical adjustment range ±0.2%FSR this circuitry. When using this circuitry, similar offset gaincalibration hardware, make adjustments following warmup. avoid interaction, always adjust offset before gain. enable three-state outputs, apply logic (low) OUTPUT ENABLE (pin 34). disable, apply logic (high) passive bandpass filter (Allen Avionics F4202 Series) used input production testing. ADS-945's digital outputs should directly connected noisy data bus. Drive with type latches "low-noise" logic, such 74LS series.
ADS-945
CALIBRATION PROCEDURE
(Refer Figure Table Note: Connect ANALOG GROUND (pin operation without zero/offset adjustment. Connect ANALOG GROUND (pin operation without gain adjustment. offset and/or gain calibration procedures should implemented until devices fully warmed avoid interaction, offset must adjusted before gain. ranges adjustment circuit Figure guaranteed compensate ADS-945's initial accuracy errors able compensate additional system errors. converters calibrated positioning their digital outputs exactly transition point between adjacent digital output codes. This accomplished connecting LED's digital outputs adjusting until certain LED's "flicker" equally between off. Other approaches employ digital comparators microcontrollers detect when outputs change from code next. ADS-945, offset adjusting normally accomplished point where other output bits just changes from This digital output transition ideally occurs when applied analog input (+76.3µV). Gain adjusting accomplished when bits just changes from This transition ideally occurs when analog input +full scale minus LSB's (+1.249771V) Note: inherent system noise, averaging several conversions needed accurately adjust both offset gain 1LSB accuracy. Zero/Offset Adjust Procedure Apply train pulses START CONVERT input (pin converter continuously converting. Apply +76.3µV ANALOG INPUT (pin Adjust offset potentiometer until output bits 0000 0000 0000 flickers between Gain Adjust Procedure Apply +1.249771V ANALOG INPUT (pin Adjust gain potentiometer until output bits flickers between confirm proper operation device, vary applied input voltage obtain output coding listed Table Note: single supply used both ANALOG DIGITAL. separate supplies used, difference between exceed 100mV. This also applies -5.2V supply requirements. Datel recommends using ferrite beads separate analog digital supplies (FAIR-RITE 2643000301.)
Table Output Coding
OUTPUT CODING 0000 0111 1111 1111 1111 0111 1111 1111 0000 0000 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1110 1111 1111
INPUT RANGE ±1.25V +1.249847 +0.937500 +0.625000 0.000000 -0.625000 -0.937500 -1.249847 -1.250000
BIPOLAR SCALE +3/4 +1/2FS -1/2FS -3/4FS
COMP. OFF. BINARY
(MSB) 10µF 0.1µF DIGITAL SUPPLY DIGITAL 58-60 GROUND DIGITAL SUPPLY ANALOG SUPPLY 0.1µF 64-68 ANALOG GROUND (LSB)
10µF -5.2V
0.1µF
10µF 10µF -5.2V 0.1µF
ANALOG SUPPLY
ADS-945
OUTPUT ENABLE OVERFLOW STATUS STATUS ANALOG INPUT
10µF
0.1µF
+15V
ANALOG 15-17 GROUND START CONVERT REF.
10µF -15V
+15V 0.1µF -15V OFFSET ADJUST GAIN ADJUST 0.1µF
+15V -15V
Figure ADS-945 Connection Diagram
+5VA
+15V
+5VD +5VA DGND VREF +5VA GAIN -15V +15V -5.2VA OFFSET +5VA +5VD -5.2VD -5.2VA -5.2VA JPR3 +15V +15V +15V -15V -15V/80MA O.F. ENABLE +15V/50MA 10PF (OPT) -5.2V 10MHZ CLOCK LT1016 +5VA/350MA +5VD OFFSET -5.2VD -15V GAIN -15V 51.1 -5.2VA ADS945
HOLE PATTERN
0.1" GRID
AGND
AGND
-5.2V
-5.2VA
-15V
DGND
POWER SUPPLY CONNECTOR
ALS573 DATA LATCHES
DATA OUTPUT CONNECTOR
-5.2VD
+5VD
-5.2V
(MSB)
-15V
JPR2 CLOCK JPR1 OUTPUT ENABLE 0.1UFD 50V. EXT. CLOCK 51.1
+15V
+5VA
(LSB)
ALS573
OVERFLOW CLOCK ENABLE
NOTES:
UNLESS OTHERWISE SPECIFIED.
RESISTORS OHMS
RN55C.
POLORIZED CAPACITORS
10UFD 25V.
POLORIZED CAPACITORS
DIODES
1N4001.
CHOKES
2UHY.
SWITCHES SHOWN
N.C. POSITION.
INSTALLED.
MONITOR OSCILLATOR TYPE 970T,
INSTALL SOCKET (ITEM 34).
REMOVE USING EXTERNAL CLOCK.
ADS-945
Figure ADS-945 Evaluation Board Schematic (DATEL Dwg. #A-23442)
ADS-945
START CONVERT 50ns typ.
10ns typ. 60ns typ. Hold
Acquisition Time
40ns typ.
Hold 55ns typ.
Hold
10ns typ. OUTPUT DATA DATA VALID DATA VALID
90ns typ. DATA VALID
INVALID DATA
Note: Scale approximately 10ns division.
Figure ADS-945 Timing Diagram
Timing Notes: ADS-945 edge-triggered device requiring additional external timing signals. rising edge start convert pulse initiates conversion. start convert pulse 50ns recommended when sampling 10MHz. falling edge subsequent start convert pulse (N+1) rising edge pulse used latch data from conversion pipeline delay). sampling rate 10MHz, connect sampling rates between 7.75 8.25MHz, place 22pF capacitor digital ground
9000
Amplitude Relative Full Scale (dB) -100 -110 -120 -130 -140 -150
8000
7000
6000
5000
4000
3000
2000
Frequency 10MHz, 4.85MHz, -0.5dB, 16,384-point FFT)
1000
Figure ADS-945 Analysis
Digital Output Code
Figure ADS-945 Grounded Input Histogram
This histogram represents typical peak-to-peak noise (including quantization noise) associated with ADS-945. 16,384 conversions were processed with input ADS-945 tied analog ground.
ADS-945
+0.39
(LSB's)
Number Occurences
-0.29
Digital Output Code
16,384
Digital Output Code
16,384
Figure ADS-945 Histogram Differential Nonlinearity
Input Frequency
Input Frequency
Peak Harmonic (-dB)
1000 10000 100000
(-dB)
1000 10000 100000
Frequency (kHz)
Frequency (kHz)
Input Frequency
SNR+D Input Frequency
Peak Harmonic (-dB)
SNR+D (dB)
1000 10000 100000
(-dB)
(dB)
1000 10000 100000
Frequency (kHz)
Frequency (kHz)
Figure ADS-945 Dynamic Performance Input Frequency +25°C
ADS-945
MECHANICAL DIMENSIONS INCHES (mm)
0.29 MAX. (7.37) 0.15 MIN. (3.81) 2.06 MAX. (52.32)
1.80 (45.72) 0.100 (2.54) TYP.
0.06 (1.52)
3.700 (93.98)
Missing keying purposes
4.02 (102.11) MAX.
4.06 (103.12) MAX.
0.25 Square (6.35) TYP. 2.02 MAX. (51.31)
Insulated surface with internal ground plane
Metal case
Epoxy glass (FR-4) base
ORDERING INFORMATION
MODEL NUMBER ADS-945 ADS-945EX OPERATING TEMP. RANGE +70°C +125°C ACCESSORIES ADS-945 Evaluation Board (without ADS-945)
9001
DS-0237E
01/96
DATEL, Inc. Cabot Boulevard, Mansfield, 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com E-mail:sales@datel.com Data Sheet Back: (508) 261-2857
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Bretonneux, France Tel: 1-34-60-01-01 DATEL GmbH Germany Tel: 89-544334-0 DATEL Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025
DATEL makes representation that products circuits described herein, other technical information contained herein, will infringe upon existing future patent rights. descriptions contained herein imply granting licenses make, use, sell equipment constructed accordance therewith. Specifications subject change without notice. DATEL logo registered DATEL, Inc. trademark.

ADS-945 14-Bit, 10MHz Sampling Converters FEATURES 14-b

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