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ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
FEATURES
* * * * * * * * * 14-bit resolution 12.8MHz minimum sampling rate No missing codes over full military temperature range Ideal for both time and frequency-domain applications Excellent THD (-81dB) and SNR (78dB) Edge-triggered Small, 32-pin, side-brazed, ceramic TDIP or SMT Low-power, 2 Watts Low cost
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
INPUT/OUTPUT CONNECTIONS
FUNCTION ViN A ViN B -5V oFFSET ADj. RANgE REF. 2.5V REF. START CoNVERT EoC ENABLE BiT 14 (LSB) BiT 13 BiT 12 BiT 11 BiT 10 BiT 9 BiT 8 PIN 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 FUNCTION RANgE gAiN ADjUST +5V ANALog ANALog gND +15V +5V DigiTAL DigiTAL gND oVERFLoW MSB BiT 1 (MSB) BiT 2 BiT 3 BiT 4 BiT 5 BiT 6 BiT 7
GENERAL DESCRIPTION
The low-cost ADS-949 is a 14-bit, 12.8MHz 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 ADS-949 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-949 contains a fast-settling sample/hold amplifier, a subranging A/D converter, an internal reference, timing/control logic, and error-correction circuitry. Digital input and output levels are TTL. The ADS-949 only requires the rising edge of a start convert pulse to operate. Requiring only +15V, +5V and -5V supplies, the ADS-949 typically dissipates just 2 Watts. The device is offered with a Bipolar input range of 2.5V and Unipolar range of 0 to 5 volts. Models are available for use in either commercial (0 to +70C) or military (-55 to +125C) operating temperature ranges.
A proprietary, auto-calibrating, error-correcting circuit allows the device to achieve specified performance over the full military temperature range.
OFFSET ADJUST 4 BUFFER VIN A VIN B 1 2 - + S/H 10 BIT 14 (LSB) FLASH ADC 1 REGISTER 2.5 V REF 6 11 BIT 13 12 BIT 12 DIGITAL CORRECTION LOGIC 13 BIT 11 OUTPUT REGISTER 14 BIT 10 15 BIT 9 16 BIT 8 17 BIT 7 18 BIT 6 19 BIT 5 20 BIT 4 21 BIT 3 22 BIT 2 23 BIT 1 (MSB) 24 MSB TIMING AND CONTROL LOGIC 9 ENABLE
POWER AND GROUNDING GAIN ADJUST +5V ANALOG SUPPLY +5V DIGITAL SUPPLY V RANGE -5.2V SUPPLY +15V SUPPLY ANALOG GROUND DIGITAL GROUND 31 30 27 32 3 28 29 26 AMP FLASH ADC 2 REGISTER REF
DAC
START CONVERT 7 EOC 8
25 OVERFLOW
Figure 1. ADS-949 Functional Block Diagram
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MDC_ADS-949.B01 Page 1 of 8
ADS 949
PHYSICAL/ENVIRONMENTAL
PARAMETERS Operating Temp. Range, Case ADS-949MC, GC ADS-949MM, GM, Thermal Impedance jc ca Storage Temperature Range Package Type Weight MIN. 0 -55 TYP. -- -- MAX. +70 +125 UNITS C C
14 Bit, 12.8MHz Sampling A/D Converters
ABSOLUTE MAXIMUM RATINGS
PARAMETERS +5V Supply (Pins 27, 30) +15V Supply (Pin 28) -5V Supply (Pin 3) Digital Input (Pin 7) Analog Input (Pins 1, 2) Lead Temperature (10 seconds) LIMITS 0 to +6 0 to +16 0 to -5.5V -0.3 to +VDD +0.3 5 +300 UNITS Volts Volts Volts Volts Volts C
-- 6 -- C/Watt -- 23 -- C/Watt -65 -- +150 C 32-pin, side-brazed, ceramic TDIP or SMT 0.46 ounces (13 grams)
FUNCTIONAL SPECIFICATIONS
(TA = +25C, +VDD = +5V, -VDD = -5V, +Vcc = +15V, 12.8MHz sampling rate, 2.5V input range, and a minimum 3 minute warmup unless otherwise specified.) +25C ANALOG INPUT Bipolar Input Voltage Range Unipolar Input Voltage Range Input Resistance (Vin A) Input Capacitance DIGITAL INPUT Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Start Convert Positive Pulse Width STATIC PERFORMANCE Resolution Integral Nonlinearity 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 (& 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 -- -- -- -- -- -- 72 72 72 70 70 69 -- -- -- -- -- -- -- -- -83 -78 -76 -81 -76 -74 78 77 76 77 74 73 150 -82 30 20 85 400 +5 2 -76 -72 -71 -74 -71 -69 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 72 72 72 70 70 69 -- -- -- -- -- -- -- -- -83 -78 -76 -81 -76 -74 78 77 76 74 74 73 150 -82 30 20 85 400 +5 2 -75 -72 -71 -74 -71 -69 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70 70 70 68 66 65 -- -- -- -- -- -- -- -- -79 -73 -71 -77 -72 -69 78 77 76 73 71 70 150 -82 30 20 85 400 +5 2 -71 -68 -65 -70 -66 -63 -- -- -- -- -- -- -- -- -- -- -- -- -- -- dB dB dB dB dB dB dB dB dB dB dB dB Vrms dB MHz MHz dB V/s ns ps rms -- -- -0.95 -- -- -- 14 14 0.75 0.5 0.15 0.1 0.2 -- -- -- +1.25 0.4 0.3 0.4 -- -- -- -0.95 -- -- -- 14 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 +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- +2.0 -- -- -- -- -- -- -- -- 50 -- +0.8 +20 -20 -- Volts Volts A A ns MIN. 1 0 to 2 -- -- TYP. -- -- 400 6 MAX. 2.5 0 to 5 -- 15 MIN. 1 0 to 2 -- -- 0 to +70C TYP. -- -- 400 6 MAX. 2.5 0 to 5 -- 15 MIN. 1 0 to 2 -- -- -55 to +125C TYP. -- -- 400 6 MAX. 2.5 0 to 5 -- 15 UNITS Volts Volts pF
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MDC_ADS-949.B01 Page 2 of 8
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
+25C DYNAMIC PERFORMANCE (Cont.) S/H Acquisition Time ( to 0.003%FSR, 5V step) Overvoltage Recovery Time A/D Conversion Rate DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding DIGITAL OUTPUTS Power Supply Ranges +5V Supply -5.2V Supply +15V Supply Power Supply Currents +5V Supply -5.2V Supply +15V Supply Power Dissipation Power Supply Rejection +4.75 -4.75 +14.5 -- -- +14.5 -- -- +5.0 -5.2 +15 +250 -200 +15 2.0 -- +5.25 -5.45 +15.5 +260 -210 +15.5 2.25 0.1 +4.75 -4.75 +14.5 -- -- +14.5 -- -- +5.0 -5.2 +15 +250 -200 +15 2.0 -- +5.25 -5.45 +15.5 +260 -210 +15.5 2.25 0.1 +4.9 -4.9 +14.5 -- -- +14.5 -- -- +5.0 -5.2 +15 +250 -200 +15 2.0 -- +5.25 -5.45 +15.5 +260 -210 +15.5 2.25 0.1 Volts Volts Volts mA mA Volts Watts %FSR/%V +2.4 -- -- -- -- -- -- -- -- +0.4 -4 +4 +2.4 -- -- -- -- -- -- -- -- +0.4 -4 +4 +2.4 -- -- -- -- -- -- -- -- +0.4 -4 +4 Volts Volts mA mA MIN. -- -- 12.8 TYP. 40 -- -- MAX. 45 100 -- MIN. -- -- 12.8 0 to +70C TYP. 40 -- -- MAX. 45 100 -- MIN. -- -- 12.8 -55 to +125C TYP. 40 -- -- MAX. 45 100 -- UNITS ns ns MHz
Straight Binary, Offset Binary
Footnotes:
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. Contact Murata Power Solutions for other input voltage ranges. A 50ns wide start convert pulse is used for all production testing. For applications requiring less than an 12.8MHz sampling rate, wider start convert pulses can be used. The rising edge of the start convert pulse needs to be as sharp as possible (<10 ns). Otherwise, a degradation in performance can result from a slow rising edge pulse. Effective bits is equal to:
(SNR + Distortion) - 1.76 + 20 log 6.02 Full Scale Amplitude Actual input Amplitude
TECHNICAL NOTES
1. obtaining fully specified performance from the ADS-949 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 (26 and 29) directly to a large analog ground plane beneath the package. Bypass all power supplies to ground with 4.7F tantalum capacitors in parallel with 0.1F ceramic capacitors. Locate the bypass capacitors as close to the unit as possible. 2. The ADS-949 achieves its specified accuracies without the need for external calibration. it is recommended that the +5VA and +5VD supplies should be powered up from the same source. if required, the device's small initial offset and gain errors can be reduced to zero using the adjustment circuitry shown in Figure 2, 3. When using this circuitry, or any similar offset and gain calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before gain. 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. 4. A passive bandpass filter is used at the input of the A/D for all production testing.
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MDC_ADS-949.B01 Page 3 of 8
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
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-949's initial accuracy errors and may not be able to compensate for additional system errors. 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. offset adjusting for the ADS-949 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 +1/2 LSB (+153V). 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 11/2 LSB's (+2.49954V). Zero/Offset Adjust Procedure 1. Apply a train of pulses to the START CoNVERT input (pin 7) so the converter is continuously converting. 2. Apply +153V to the ANALog iNPUT (pin 1). 3. Adjust the offset potentiometer until the output bits are 10 0000 0000 0000 and the LSB flickers between 0 and 1. Gain Adjust Procedure 1. Apply +2.49954V to the ANALog iNPUT (pin 1). 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.
Table 1. Gain and Zero Adjust
INPUT VOLTAGE RANGE 2.5V
ZERO ADJUST +1/2 LSB +153V
GAIN ADJUST +FS -11/2 LSB +2.49954V
-5V +15V 4.7F + 4.7F +
+5VA
+5VD 4.7F +
4.7F +
0.1F 0.1F
0.1F
0.1F
3 -5V +5V GAIN ADJUST 20K -5V
28 30 29 +15V AGND +5VA
27 26 +5VD DGND
5 RANGE REF BIPOLAR ANALOG INPUT +5V ZERO/ OFFSET ADJUST 20k -5V START CONVERT 2 VIN B 1VIN A 31 GAIN ADJUST ADS-949
23 BIT 1 (MSB) 22 BIT 2 21 BIT 3 20 BIT 4 19 18 17 16 15 14 13 12 11 10 8 BIT 5 BIT 6 BIT 7 BIT 8 BIT 9 BIT 10 BIT 11 BIT 12 BIT 13 BIT 14 (LSB) EOC
4 OFFSET ADJUST 20k
32 RANGE 6 2.5V REF 7 START CONVERT 9 ENABLE
Bypass Pins 5, 6, 32, with a 4.7F to Analog Ground. Note: The Voltage Value at Pin 32 (Range) sets the input voltage range of the ADS-949 eg: If Pin 6 (2.5V Reference Out) is tied to the Range Pin 32 (20k Pot is shorted), then the input range of the ADS-949 becomes 2.5V If the 20k Pot is set at midrange then the input range of the ADS-949 becomes 1.25V
Figure 2. Typical ADS-949 Bipolar Connection Diagram
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MDC_ADS-949.B01 Page 4 of 8
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
THERMAL REQUIREMENTS
All MPS sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70C and -55 to +125C. All room temperature (TA = +25C) 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 MPS's HS Series heat sinks. See ordering information for the assigned part number. See page 1-183 of the MPS Data Acquisition Components Catalog for more information on the HS Series. Request MPS Application Note AN8, "Heat Sinks for DiP Data Converters", or contact Murata Power Solutions directly, for additional information.
Table 3. Output Coding STRAIGHT BIN. UNIPOLAR SCALE INPUT VOLT. 0 TO +5V MSB LSB OUTPUT CODING MSB LSB INPUT VOLT. 2.5V BIPOLAR SCALE
+FS - 1 LSB +7/8 FS +3/4 FS +1/2 FS +1/4 FS +1/8 FS +1 LSB 0
+4.999695 +4.375000 +3.75000 +2.500000 +1.250000 +0.625000 +0.000305 0.000000
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
OFF. BINARY
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.
+2.499695 +1.875000 +1.250000 0.000000 -1.250000 -1.875000 -2.499695 -2.500000
+FS - 1LSB +3/4FS +1/2FS 0 -1/2FS -3/4FS -FS+1LSB -FS
-5V +15V 4.7F + 4.7F +
+5VA
+5VD 4.7F +
4.7F +
0.1F 0.1F
0.1F
0.1F
+5V GAIN ADJUST 20K -5V
UNIPOLAR ANALOG INPUT +5V ZERO/ OFFSET ADJUST 20k -5V START CONVERT
5 3 RANGE REF -5V 1VIN A 2 VIN B 31 GAIN ADJUST
28 30 29 +15V AGND +5VA
27 26 +5VD DGND
ADS-949 4 OFFSET ADJUST 20k
32 RANGE 6 2.5V REF 7 START CONVERT 9 ENABLE
23 22 21 20 19 18 17 16 15 14 13 12 11 10 8
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) EOC
Figure 3. Typical ADS-949 Unipolar Connection Diagram
Bypass Pins 5, 6, 32 with a 4.7F to Analog Ground.
www.murata-ps.com 32 (Range) sets the input voltage range of the ADS-949 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 Note: The Voltage Value at Pin
MDC_ADS-949.B01 Page 5 of 8 eg: If Pin 6 (2.5V Reference Out) is tied to the Range Pin 32 (20k Pot is shorted), then the input range of the ADS-949 becomes 0 to 5V
If the 20k Pot is set at midrange then the input range of the ADS-949 becomes 0 to 2.5V
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
Figure 4. FFT Analysis of ADS-949 (fs = 12.8MHz, fin = 3.85MHz, Vin = -0.5dB, 16,384 point FFT)
Figure 5. ADS-949 Histogram
START CONVERT Minimum is 40ns
N 40ns
N+1
EOC 40ns 60ns DATA OUT 20ns ENABLED 30ns OUTPUT DATA ENABLED DATA N-3 HZ 20ns Notes: 1. Scale is approximately 10ns per division. All values are Typical. 2. Rising edge of the start convert needs to be less than 10 ns. DATA N-2 HZ DATA N-1 HZ DATA N HZ DATA N-3 DATA N-2 DATA N-1 DATA N
Figure 6. ADS-949 Timing Diagram
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MDC_ADS-949.B01 Page 6 of 8
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
CONTACT MURATA POWER SOLUTIONS FOR SCHEMATIC
Figure 7. ADS-949 Evaluation Board Schematic (ADS-B949)
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MDC_ADS-949.B01 Page 7 of 8
ADS 949
14 Bit, 12.8MHz Sampling A/D Converters
MECHANICAL DIMENSIONS
INCHES (mm)
1.62 MAX. (41.15)
Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) 0.010 (0.254) 3 place decimal (.XXX) 0.005 (0.127)
0.92 MAX. (23.37)
Lead Material: Kovar Alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating
1.50 TYP (38.10) 0.220 TYP. (6.86) PIN 1 INDEX SEATING PLANE 0.05 TYP. (1.27)
0.010 TYP. (0.254) 0.05 TYP. (1.27) 0.018 TYP. (0.46) 0.100 TYP. (2.54) 0.05 TYP. (1.27) 0.90 TYP. (22.86)
0.175 TYP (4.45)
ORDERING INFORMATION
MODEL ADS-949MC ADS-949MM ADS-949/883 ADS-949GC ADS-949GM OPERATING TEMP. RANGE 0 to +70C -55 to +125C -55 to +125C 0 to +70C -55 to +125C 32-PIN PACKAGE TDiP TDiP TDiP SMT SMT ACCESSORIES ADS-B949 HS-32 Evaluation Board (without ADS-949) Heat sink for ADS-949 TDiP models
Receptacles for PC board mounting can be ordered through AMP, inc., Part # 3-331272-8 (Component Lead Socket), 32 required. For MiL-STD-883 product specifcation, contact Murata Power Solutions.
USA: Canada: UK: France: Tucson (AZ), Tel: (800) 547 2537, email: sales@murata-ps.com Toronto, Tel: (866) 740 1232, email: toronto@murata-ps.com Milton Keynes, Tel: +44 (0)1908 615232, email: mk@murata-ps.com Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: france@murata-ps.com Tokyo, Tel: 3-3779-1031, email: sales_tokyo@murata-ps.com Osaka, Tel: 6-6354-2025, email: sales_osaka@murata-ps.com Website: www.murata-ps.jp Shanghai, Tel: +86 215 027 3678, email: shanghai@murata-ps.com Guangzhou, Tel: +86 208 221 8066, email: guangzhou@murata-ps.com
Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
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email: sales@murata-ps.com
3/14/08
China:
Murata Power Solutions, Inc. 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. (c) 2008 Murata Power Solutions, Inc.
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