®

®

ADS-929

3

+25°C

0 to +70°C

–55 to +125°C

ANALOG OUTPUT

MIN.

TYP.

MAX.

MIN.

TYP.

MAX.

MIN.

TYP.

MAX.

UNITS

Internal Reference

Voltage

+9.95

+10.0

+10.05

+9.95

+10.0

+10.05

+9.95

+10.0

+10.05

Volts

Drift

—

±5

—

—

±5

—

—

±5

—

ppm/°C

External Current

—

—

1.5

—

—

1.5

—

—

1.5

mA

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

Delay, Falling Edge of EOC

to Output Data Valid

—

—

35

—

—

35

—

—

35

ns

Output Coding

Offset Binary

POWER REQUIREMENTS, ±15V

Power Supply Ranges

+15V Supply

+14.5

+15.0

+15.5

+14.5

+15.0

+15.5

+14.5

+15.0

+15.5

Volts

–15V Supply

–14.5

–15.0

–15.5

–14.5

–15.0

–15.5

–14.5

–15.0

–15.5

Volts

+5V Supply

+4.75

+5.0

+5.25

+4.75

+5.0

+5.25

+4.75

+5.0

+5.25

Volts

Power Supply Currents

+15V Supply

—

+45

+55

—

+45

+55

—

+45

+55

mA

–15V Supply

—

–43

–50

—

–43

–50

—

–43

–50

mA

+5V Supply

—

+80

+90

—

+80

+90

—

+80

+90

mA

Power Dissipation

—

1.7

1.9

—

1.7

1.9

—

1.7

1.9

Watts

Power Supply Rejection

—

—

±0.01

—

—

±0.01

—

—

±0.01

%FSR/%V

POWER REQUIREMENTS, ±12V

Power Supply Ranges

+12V Supply

+11.5

+12.0

+12.5

+11.5

+12.0

+12.5

+11.5

+12.0

+12.5

Volts

–12V Supply

–11.5

–12.0

–12.5

–11.5

–12.0

–12.5

–11.5

–12.0

–12.5

Volts

+5V Supply

+4.75

+5.0

+5.25

+4.75

+5.0

+5.25

+4.75

+5.0

+5.25

Volts

Power Supply Currents

+12V Supply

—

+45

+55

—

+45

+55

—

+45

+55

mA

–12V Supply

—

–43

–50

—

–43

–50

—

–43

–50

mA

+5V Supply

—

+80

+90

—

+80

+90

—

+80

+90

mA

Power Dissipation

—

1.4

1.6

—

1.4

1.6

—

1.4

1.6

Watts

Power Supply Rejection

—

—

±0.01

—

—

±0.01

—

—

±0.01

%FSR/%V

TECHNICAL NOTES

1. Obtaining fully specified performance from the ADS-929

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 beneath the

package.

Bypass all power supplies, as well as the REFERENCE

OUTPUT (pin 21), to ground with 4.7µF tantalum capaci-

tors 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 shown in

Figure 2 is used, also locate it as close to the ADS-929 as

possible.

2. The ADS-929 achieves its specified accuracies without the

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 adjust-

ments following warmup. To avoid interaction, always adjust

offset before gain.

3. When operating the ADS-929 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.

6.02

(SNR + Distortion) – 1.76 +

20 log

Full Scale Amplitude

Actual Input Amplitude

 Effective bits is equal to:

 This is the time required before the A/D output data is valid after the analog input

is back within the specified range.

Footnotes:

ΠAll 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 2MHz clock with a 200ns wide start convert pulse is used for all production

testing. See Timing Diagram for more details.