ADS-949/883 - Murata Power Solutions

Figure 1. ADS-949 Functional Block Diagram

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

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 ampliﬁ er, 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.

A proprietary, auto-calibrating, error-correcting circuit allows

the device to achieve speciﬁ ed performance over the full

military temperature range.

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 VIN A 32 RANGE

2 VIN B 31 GAIN ADJUST

3 –5V 30 +5V ANALOG

4 OFFSET ADJ. 29 ANALOG GND

5 RANGE REF. 28 +15V

6 2.5V REF. 27 +5V DIGITAL

7 START CONVERT 26 DIGITAL GND

8 EOC 25 OVERFLOW

9 ENABLE 24 MSB

10 BIT 14 (LSB) 23 BIT 1 (MSB)

11 BIT 13 22 BIT 2

12 BIT 12 21 BIT 3

13 BIT 11 20 BIT 4

14 BIT 10 19 BIT 5

15 BIT 9 18 BIT 6

16 BIT 8 17 BIT 7

REF

DAC

OUTPUT REGISTER

10 BIT 14 (LSB)

11 BIT 13

12 BIT 12

13 BIT 11

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

OFFSET ADJUST 4

VIN A 1

START CONVERT 7

EOC 8

GAIN ADJUST 31

+5V ANALOG SUPPL 30

+5V DIGITAL SUPPL 27

V RANGE 32

–5.2V SUPPL 3

+15V SUPPL 28

ANALOG GROUND 29

DIGITAL GROUND 26

–

S/H

BUFFER

DIGITAL CORRECTION LOGIC

FLASH

ADC

FLASH

ADC

POWER AND GROUNDING

AMP

9 ENABLE

25 OVERFLOW

VIN B 2

2.5 V REF 6

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 1 of 8

+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 ±1 — ±2.5 ±1 — ±2.5 ±1 — ±2.5 Volts

Unipolar Input Voltage Range ➁ 0 to 2 — 0 to 5 0 to 2 — 0 to 5 0 to 2 — 0 to 5 Volts

Input Resistance (Vin A) — 400 — — 400 — — 400 — Ω

Input Capacitance — 6 15 — 6 15 — 6 15 pF

DIGITAL INPUT

Logic Levels

Logic "1" +2.0 — — +2.0 — — +2.0 — — Volts

Logic "0" — — +0.8 — — +0.8 — — +0.8 Volts

Logic Loading "1" — — +20 — — +20 — — +20 µA

Logic Loading "0" — — –20 — — –20 — — –20 µA

Start Convert Positive Pulse Width ➂ — 50 — — 50 — — 50 — ns

STATIC PERFORMANCE

Resolution — 14 — — 14 — — 14 — Bits

Integral Nonlinearity — ±0.75 — — ±0.75 — — ±1 — LSB

Differential Nonlinearity (fin = 10kHz) – 0.95 ±0.5 +1.25 –0.95 ±0.5 +1.25 –0.95 ±0.5 +1.5 LSB

Full Scale Absolute Accuracy — ±0.15 ±0.4 — ±0.15 ±0.4 — ±0.4 ±0.8 %FSR

Bipolar Zero Error (Tech Note 2) — ±0.1 ±0.3 — ±0.1 ±0.3 — ±0.3 ±0.6 %FSR

Gain Error (Tech Note 2) — ±0.2 ±0.4 — ±0.2 ±0.4 — ±0.4 ±1.5 %

No Missing Codes (fin = 10kHz) 14 — — 14 — — 14 — — Bits

DYNAMIC PERFORMANCE

Peak Harmonics (–0.5dB)

dc to 1MHz — –83 –76 — –83 –75 — –79 –71 dB

1MHz to 2.5MHz — –78 –72 — –78 –72 — –73 –68 dB

2.5MHz to 5MHz — –76 –71 — –76 –71 — –71 –65 dB

Total Harmonic Distortion (–0.5dB)

dc to 1MHz — –81 –74 — –81 –74 — –77 –70 dB

1MHz to 2.5MHz — –76 –71 — –76 –71 — –72 –66 dB

2.5MHz to 5MHz — –74 –69 — –74 –69 — –69 –63 dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB)

dc to 1MHz 72 78 — 72 78 — 70 78 — dB

1MHz to 2.5MHz 72 77 — 72 77 — 70 77 — dB

2.5MHz to 5MHz 72 76 — 72 76 — 70 76 — dB

Signal-to-Noise Ratio ➃

(& distortion, –0.5dB)

dc to 1MHz 70 77 — 70 74 — 68 73 — dB

1MHz to 2.5MHz 70 74 — 70 74 — 66 71 — dB

2.5MHz to 5MHz 69 73 — 69 73 — 65 70 — dB

Noise — 150 — — 150 — — 150 — µVrms

Two-tone Intermodulation

Distortion (fin = 2.45MHz,

1.975MHz, fs = 10MHz, –0.5dB) — –82 — — –82 — — –82 — dB

Input Bandwidth (–3dB)

Small Signal (–20dB input) — 30 — — 30 — — 30 — MHz

Large Signal (–0.5dB input) — 20 — — 20 — — 20 — MHz

Feedthrough Rejection (fin = 5MHz) — 85 — — 85 — — 85 — dB

Slew Rate — ±400 — — ±400 — — ±400 — V/µs

Aperture Delay Time — +5 — — +5 — — +5 — ns

Aperture Uncertainty — 2 — — 2 — — 2 — ps rms

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 speciﬁ ed.)

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+5V Supply (Pins 27, 30) 0 to +6 Volts

+15V Supply (Pin 28) 0 to +16 Volts

–5V Supply (Pin 3) 0 to –5.5V Volts

Digital Input (Pin 7) –0.3 to +VDD +0.3 Volts

Analog Input (Pins 1, 2) ±5 Volts

Lead Temperature (10 seconds) +300 °C

PARAMETERS MIN. TYP. MAX. UNITS

Operating Temp. Range, Case

ADS-949MC, GC 0 — +70 °C

ADS-949MM, GM, –55 — +125 °C

Thermal Impedance

θjc — 6 — °C/Watt

θca — 23 — °C/Watt

Storage Temperature Range –65 — +150 °C

Package Type 32-pin, side-brazed, ceramic TDIP or SMT

Weight 0.46 ounces (13 grams)

PHYSICAL/ENVIRONMENTAL

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 2 of 8

+25°C 0 to +70°C –55 to +125°C

DYNAMIC PERFORMANCE (Cont.) MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS

S/H Acquisition Time

( to ±0.003%FSR, 5V step) — 40 45 — 40 45 — 40 45 ns

Overvoltage Recovery Time — — 100 — — 100 — — 100 ns

A/D Conversion Rate 12.8 — — 12.8 — — 12.8 — — MHz

DIGITAL OUTPUTS

Logic Levels

Logic "1" +2.4 — — +2.4 — — +2.4 — — Volts

Logic "0" — — +0.4 — — +0.4 — — +0.4 Volts

Logic Loading "1" — — –4 — — –4 — — –4 mA

Logic Loading "0" — — +4 — — +4 — — +4 mA

Output Coding

DIGITAL OUTPUTS

Power Supply Ranges

+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.9 +5.0 +5.25 Volts

–5.2V Supply –4.75 –5.2 –5.45 –4.75 –5.2 –5.45 –4.9 –5.2 –5.45 Volts

+15V Supply +14.5 +15 +15.5 +14.5 +15 +15.5 +14.5 +15 +15.5 Volts

Power Supply Currents

+5V Supply — +250 +260 — +250 +260 — +250 +260 mA

–5.2V Supply — –200 –210 — –200 –210 — –200 –210 mA

+15V Supply +14.5 +15 +15.5 +14.5 +15 +15.5 +14.5 +15 +15.5 Volts

Power Dissipation — 2.0 2.25 — 2.0 2.25 — 2.0 2.25 Watts

Power Supply Rejection — — ±0.1 — — ±0.1 — — ±0.1 %FSR/%V

Footnotes:

TECHNICAL NOTES

1. Obtaining fully speciﬁ ed 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 opti-

mal 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 speciﬁ ed 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 ﬁ lter is used at the input of the

A/D for all production testing.

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.

➁ Contact DATEL 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.

➃ Effective bits is equal to:

(SNR + Distortion) – 1.76 + 20 log

Full Scale Amplitude

Actual Input Amplitude

6.02

Straight Binary, Offset Binary

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 3 of 8

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 “ﬂ icker” 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

+½ LSB (+153µV).

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).

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 +153µV to the ANALOG INPUT (pin 1).

3. Adjust the offset potentiometer until the output bits are

10 0000 0000 0000 and the LSB ﬂ ickers 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 ﬂ ickers between 1 and 0.

3. To conﬁ rm proper operation of the device, vary the input signal

to obtain the output coding listed in Table 2.

INPUT VOLTAGE ZERO ADJUST GAIN ADJUST

RANGE +½ LSB +FS –1½ LSB

±2.5V +153µV +2.49954V

Table 1. Gain and Zero Adjust

Figure 2. Typical ADS-949 Bipolar Connection Diagram

0.1µF

4.7µF

+5VD

AGND

ADS-949

20k

4.7µF

+5VA

DGND

+5V

1VIN A

4 OFFSET AD UST

7 START CONVERT

BIT 1 (MSB)

BIT 2

BIT 3

BIT 4

BIT 5

BIT

BIT 7

BIT

BIT 9

BIT 10

BIT 11

BIT 12

BIT 13

BIT 14 (LSB)

EOC

BIPOLAR

ANALOG

INPUT

START

CONVERT

➀

Bypass Pins 5, , 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 (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

ERO/

OFFSET

AD UST

+5V

31 GAIN AD UST

GAIN

DUST

2 VIN B

9 ENABLE

20k

2.5V REF

➀

32 RANGE

➀

+15V

+5VD

4.7µF

+5VA

0.1µF 0.1µF

4.7µF

0.1µF

5 RANGE REF

➀

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 4 of 8

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 ﬂ ow 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.

THERMAL REQUIREMENTS

All DATEL sampling A/D converters are fully characterized and

speciﬁ ed 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 ﬁ gures for each device are listed in

their respective speciﬁ cation 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.

Figure 3. Typical ADS-949 Unipolar Connection Diagram

Table 3. Output Coding

UNIPOLAR INPUT VOLT. OUTPUT CODING INPUT VOLT. BIPOLAR

SCALE 0 TO +5V MSB LSB MSB LSB ±2.5V SCALE

+FS – 1 LSB +4.999695 11 1111 1111 1111 01 1111 1111 1111 +2.499695 +FS – 1LSB

+7/8 FS +4.375000 11 1000 0000 0000 01 1000 0000 0000 +1.875000 +3/4FS

+3/4 FS +3.75000 11 0000 0000 0000 01 0000 0000 0000 +1.250000 +1/2FS

+1/2 FS +2.500000 10 0000 0000 0000 00 0000 0000 0000 0.000000 0

+1/4 FS +1.250000 01 0000 0000 0000 11 0000 0000 0000 –1.250000 –1/2FS

+1/8 FS +0.625000 00 1000 0000 0000 10 1000 0000 0000 –1.875000 –3/4FS

+1 LSB +0.000305 00 0000 0000 0001 10 0000 0000 0001 –2.499695 –FS+1LSB

0 0.000000 00 0000 0000 0000 10 0000 0000 0000 –2.500000 –FS

STRAIGHT BIN.

OFF. BINARY TWO'S COMP.

0.1 F

4.7 F

+5 D

AND

–5

ADS-949

20k

4.7 F

+5 A

DND

–5

1IN A

4 OFFSET AD ST

7 START CON ERT

BIT 1 ( SB)

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

NIPOLAR

ANALO

INP T

START

CON ERT

ERO/

OFFSET

AD ST

–5

31 AIN AD ST

AIN

DST

–5

2 IN B

9 ENABLE

20k

6 2.5 REF

➀

32 RAN E

➀

+15

+5 D

4.7 F

+5 A

0.1 F 0.1 F

4.7 F

0.1 F

RAN E REF

➀

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 5 of 8

Figure 4. FFT Analysis of ADS-949

(fs = 12.8MHz, ﬁ n = 3.85MHz, Vin = –0.5dB, 16,384 point FFT)

Figure 5. ADS-949 Histogram

Figure 6. ADS-949 Timing Diagram

START

CONVERT

Minimum is 40ns

OUTPUT

DATA

ENABLED

EOC

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 OUT

ENABLED

N+1

40ns

20ns

60ns

DATA N-3 DATA N-2 DATA N-1 DATA N

30ns

20ns

DATA N-3 DATA N-2 DATA N-1 DATA N

HZ HZ HZ HZ

ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 6 of 8

Figure 7. ADS-949 Evaluation Board Schematic (ADS-B949)

CONTACT DATEL FOR SCHEMATIC

MECHANICAL DIMENSIONS – STANDARD PACKAGE

INCHES (mm)

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ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

23 Feb 2012 MDA_ADS-949.B04 Page 7 of 8

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 DATEL.

MECHANICAL DIMENSIONS – SURFACE MOUNT PACKAGE

INCHES (mm)

OPERATING 32-PIN

MODEL TEMP. RANGE PACKAGE

ADS-949MC 0 to +70°C TDIP

ADS-949MM –55 to +125°C TDIP

ADS-949/883 –55 to +125°C TDIP

ADS-949GC 0 to +70°C SMT

ADS-949GM –55 to +125°C SMT

ORDERING INFORMATION

ACCESSORIES

ADS-B949 Evaluation Board (without ADS-949)

HS-32 Heat sink for ADS-949 TDIP models

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ADS 949

14 Bit, 12.8MHz Sampling A/D Converters

. 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. Speciﬁ cations are subject to change

without notice.

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23 Feb 2012 MDA_ADS-949.B04 Page 8 of 8