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 INPUT/OUTPUT CONNECTIONS PIN 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 +70°C) or military (–55 to +125°C) operating temperature ranges. FUNCTION PIN 1 Vin a 2vin b 3 –5V 4 offset adj. 5 Range Ref. 6 2.5V ref. 7 START CONVERT 8 EOC 9enable 10 BIT 14 (LSB) 11 BIT 13 12 BIT 12 13bit 11 14bit 10 15 BIT 9 16bit 8 FUNCTION 32 Range 31Gain Adjust 30 +5V Analog 29 Analog GND 28 +15V 27 +5V Digital 26 Digital GND 25Overflow 24msb 23 BIT 1 (MSB) 22bit 2 21 BIT 3 20 BIT 4 19 BIT 5 18 BIT 6 17bit 7 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 1 VIN B 2 – + 9 ENABLE S/H 10 BIT 14 (LSB) 11 BIT 13 12 BIT 12 POWER AND GROUNDING 31 +5V ANALOG SUPPLY 30 +5V DIGITAL SUPPLY 27 V RANGE 32 –5.2V SUPPLY 3 +15V SUPPLY 28 ANALOG GROUND 29 DIGITAL GROUND 26 START CONVERT 7 EOC 8 REF DAC � AMP FLASH ADC 2 REGISTER GAIN ADJUST 13 BIT 11 OUTPUT REGISTER DIGITAL CORRECTION LOGIC FLASH ADC 1 REGISTER 2.5 V REF 6 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 25 OVERFLOW Figure 1. ADS-949 Functional Block Diagram www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_ADS-949.B01 Page 1 of 8 ADS 949 14 Bit, 12.8MHz Sampling A/D Converters PHYSICAL/ENVIRONMENTAL PARAMETERS Operating Temp. Range, Case ADS-949MC, GC ADS-949MM, GM, Thermal Impedance θjc θca Storage Temperature Range Package Type Weight MIN. TYP. MAX. UNITS 0 –55 — — +70 +125 °C °C — 6 — °C/Watt — 23 — °C/Watt –65 — +150 °C 32-pin, side-brazed, ceramic TDIP or SMT 0.46 ounces (13 grams) ABSOLUTE MAXIMUM RATINGS PARAMETERS LIMITS +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) UNITS 0 to +6 0 to +16 0 to –5.5V –0.3 to +VDD +0.3 ±5 +300 Volts Volts Volts Volts Volts °C FUNCTIONAL SPECIFICATIONS (TA = +25°C, +VDD = +5V, –VDD = –5V, +Vcc = +15V, 12.8MHz sampling rate, ±2.5V input range, and a minimum 3 minute warmup ➀ unless otherwise specified.) +25°C 0 to +70°C –55 to +125°C ANALOG INPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS Bipolar Input Voltage Range ➁ Unipolar Input Voltage Range ➁ Input Resistance (Vin A) Input Capacitance ±1 0 to 2 — — — — 400 6 ±2.5 0 to 5 — 15 ±1 0 to 2 — — — — 400 6 ±2.5 0 to 5 — 15 ±1 0 to 2 — — — — 400 6 ±2.5 0 to 5 — 15 Volts Volts Ω pF +2.0 — — — — — — — — 50 — +0.8 +20 –20 — +2.0 — — — — — — — — 50 — +0.8 +20 –20 — +2.0 — — — — — — — — 50 — +0.8 +20 –20 — Volts Volts µA µA ns — — –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 — — — –83 –78 –76 –76 –72 –71 — — — –83 –78 –76 –75 –72 –71 — — — –79 –73 –71 –71 –68 –65 dB dB dB — — — –81 –76 –74 –74 –71 –69 — — — –81 –76 –74 –74 –71 –69 — — — –77 –72 –69 –70 –66 –63 dB dB dB 72 72 72 78 77 76 — — — 72 72 72 78 77 76 — — — 70 70 70 78 77 76 — — — dB dB dB 70 70 69 — 77 74 73 150 — — — — 70 70 69 — 74 74 73 150 — — — — 68 66 65 — 73 71 70 150 — — — — dB dB dB µVrms — –82 — — –82 — — –82 — dB — — — — — — 30 20 85 ±400 +5 2 — — — — — — — — — — — — 30 20 85 ±400 +5 2 — — — — — — — — — — — — 30 20 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 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 www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_ADS-949.B01 Page 2 of 8 ADS 949 14 Bit, 12.8MHz Sampling A/D Converters +25°C DYNAMIC PERFORMANCE (Cont.) MIN. S/H Acquisition Time ( to ±0.003%FSR, 5V step) Overvoltage Recovery Time A/D Conversion Rate 0 to +70°C TYP. MAX. — — 12.8 40 — — 45 100 — +2.4 — — — — — — — — +0.4 –4 +4 MIN. –55 to +125°C TYP. MAX. — — 12.8 40 — — 45 100 — +2.4 — — — — — — — — +0.4 –4 +4 MIN. TYP. MAX. UNITS — — 12.8 40 — — 45 100 — ns ns MHz +2.4 — — — — — — — — +0.4 –4 +4 Volts Volts mA mA DIGITAL OUTPUTS Logic Levels Logic "1" Logic "0" Logic Loading "1" Logic Loading "0" Output Coding Straight Binary, Offset Binary 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 +5.0 –5.2 +15 +5.25 –5.45 +15.5 +4.75 –4.75 +14.5 +5.0 –5.2 +15 +5.25 –5.45 +15.5 +4.9 –4.9 +14.5 +5.0 –5.2 +15 +5.25 –5.45 +15.5 Volts Volts Volts — — +14.5 — — +250 –200 +15 2.0 — +260 –210 +15.5 2.25 ±0.1 — — +14.5 — — +250 –200 +15 2.0 — +260 –210 +15.5 2.25 ±0.1 — — +14.5 — — +250 –200 +15 2.0 — +260 –210 +15.5 2.25 ±0.1 mA mA Volts Watts %FSR/%V Footnotes: 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. ➃ Effective bits is equal to: (SNR + Distortion) – 1.76 + 20 log Full Scale Amplitude Actual Input Amplitude 6.02 ➁ Contact Murata Power Solutions for other input voltage ranges. ➂ 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. 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 4.7µF tantalum capacitors in parallel with 0.1µF 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 www.murata-ps.com 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. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_ADS-949.B01 Page 3 of 8 ADS 949 14 Bit, 12.8MHz Sampling A/D Converters CALIBRATION PROCEDURE Zero/Offset Adjust 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. 1. Apply a train of pulses to the START CONVERT input (pin 7) so the converter is continuously converting. 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. Gain Adjust Procedure 2. Apply +153µV 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. 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. 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 +½ LSB (+153µV). Table 1. Gain and Zero Adjust INPUT VOLTAGE RANGE 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 (+2.49954V). –5V ZERO ADJUST +½ LSB GAIN ADJUST +FS –1½ LSB +153µV +2.49954V ±2.5V +5VA +5VD +15V 4.7µF + 4.7µF + 0.1µF 0.1µF 3 –5V 4.7µF + 4.7µF + 0.1µF 0.1µF 28 30 29 +15V AGND +5VA 27 26 +5VD DGND 5 RANGE REF ➀ +5V GAIN ADJUST 20K 1VIN A 31 GAIN ADJUST +5V ZERO/ OFFSET ADJUST –5V 20k 21 BIT 3 20 BIT 4 2 VIN B BIPOLAR ANALOG INPUT 19 18 17 16 15 14 13 12 11 10 8 ADS-949 4 OFFSET ADJUST 20k� –5V START CONVERT 23 BIT 1 (MSB) 22 BIT 2 32 RANGE ➀ 6 2.5V REF ➀ 7 START CONVERT 9 ENABLE BIT 5 BIT 6 BIT 7 BIT 8 BIT 9 BIT 10 BIT 11 BIT 12 BIT 13 BIT 14 (LSB) EOC ➀ Bypass Pins 5, 6, 32, with a 4.7µF 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 www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 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 +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 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 INPUT VOLT. OUTPUT CODING sCALE 0 TO +5vmsblsbmsblsb INPUT VOLT. BIPOLAR ±2.5vsCALE +FS – 1 LSB +7/8 FS +3/4 FS +1/2 FS +1/4 FS +1/8 FS +1 LSB 0 +2.499695 +1.875000 +1.250000 0.000000 –1.250000 –1.875000 –2.499695 –2.500000 +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 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 +FS – 1LSB +3/4FS +1/2FS 0 –1/2FS –3/4FS –FS+1LSB –FS TWO'S COMP. –5V +5VA +5VD +15V 4.7µF + 4.7µF + 0.1µF 0.1µF +5V GAIN ADJUST 20K 5 3 RANGE REF ➀ –5V 1VIN A UNIPOLAR ANALOG INPUT 4.7µF + 4.7µF + 0.1µF 0.1µF 28 30 29 +15V AGND +5VA 27 26 +5VD DGND 2 VIN B 31 GAIN ADJUST +5V ADS-949 ZERO/ OFFSET ADJUST –5V 20k 4 OFFSET ADJUST 20k� –5V START CONVERT 32 RANGE ➀ 6 2.5V REF ➀ 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 ➀ Bypass Pins 5, 6, 32 with a 4.7µF to Analog Ground. www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 Note: The Voltage Value at Pin 32 (Range) sets the input voltage range of the ADS-949 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 Figure 5. ADS-949 Histogram (fs = 12.8MHz, fin = 3.85MHz, Vin = –0.5dB, 16,384 point FFT) START CONVERT Minimum is 40ns N N+1 40ns EOC 40ns 60ns DATA OUT DATA N-3 DATA N-2 DATA N-1 DATA N 20ns ENABLED 30ns OUTPUT DATA ENABLED DATA N-3 DATA N-2 HZ DATA N-1 HZ DATA N HZ 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. Figure 6. ADS-949 Timing Diagram www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 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) www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 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) SEATING PLANE 0.05 TYP. (1.27) 0.220 TYP. (6.86) PIN 1 INDEX 0.010 TYP. (0.254) 0.05 TYP. (1.27) 0.018 TYP. (0.46) 0.100 TYP. (2.54) 0.90 TYP. (22.86) 0.175 TYP (4.45) 0.05 TYP. (1.27) ORDERING INFORMATION MODEL ADS-949MC ADS-949MM ADS-949/883 ADS-949GC ADS-949GM OPERATING TEMP. RANGE 0 to +70°C –55 to +125°C –55 to +125°C 0 to +70°C –55 to +125°C 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: Tucson (AZ), Tel: (800) 547 2537, email: [email protected] Canada: Toronto, Tel: (866) 740 1232, email: [email protected] UK: Milton Keynes, Tel: +44 (0)1908 615232, email: [email protected] France: Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: [email protected] Germany: München, Tel: +49 (0)89-544334-0, email: [email protected] 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 www.murata-ps.com ISO 9001 REGISTERED email: [email protected] 3/14/08 Japan: Tokyo, Tel: 3-3779-1031, email: [email protected] Osaka, Tel: 6-6354-2025, email: [email protected] Website: www.murata-ps.jp China: Shanghai, Tel: +86 215 027 3678, email: [email protected] Guangzhou, Tel: +86 208 221 8066, email: [email protected] 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. © 2008 Murata Power Solutions, Inc. www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_ADS-949.B01 Page 8 of 8