ADS-949GM View Datasheet(PDF) - Murata Power Solutions

Part Name

Description

MFG CO.

ADS-949GM

14 Bit, 12.8MHz Sampling A/D Converters

Murata Power Solutions 

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 +5v msb lsb msb lsb

INPUT VOLT.

BIPOLAR

±2.5v 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

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

+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

OFF. BINARY

TWO'S COMP.

–5V

+15V

4.7µF 4.7µF

+

+

+5VA

4.7µF

+

+5VD

4.7µF

+

0.1µF 0.1µF

0.1µF

0.1µF

+5V

GAIN

ADJUST

20K

–5V

UNIPOLAR

ANALOG

INPUT

+5V

5

3

RANGE REF ➀ –5V

1VIN A

2 VIN B

31 GAIN ADJUST

ZERO/

OFFSET

ADJUST

4 OFFSET ADJUST

20k�

20k

–5V

START

CONVERT

32 RANGE ➀

6 2.5V REF ➀

7 START CONVERT

9 ENABLE

28 29 30 27 26

+15V AGND +5VA +5VD DGND

ADS-949

23 BIT 1 (MSB)

22 BIT 2

21 BIT 3

20 BIT 4

19 BIT 5

18 BIT 6

17 BIT 7

16 BIT 8

15 BIT 9

14 BIT 10

13 BIT 11

12 BIT 12

11 BIT 13

10 BIT 14 (LSB)

8 EOC

Figure 3. Typical ADS-949 Unipolar Connection Diagram

➀ Bypass Pins 5, 6, 32 with a 4.7µF to Analog Ground.

wwNowte.:mThue rVaolttaage-pVasl.uceoatmPin 32 (Range) sets the iTnepcuhtnvicoalltaegnqeuriarinesgeemoafilt:hsealeAsD@Sm-u9r4at9a-ps.com, tel: +1 508 339 3000

eg: If Pin 6 (2.5V Reference Out) is tied to the Range Pin 32 (20k Pot is shorted), thenMDC_ADS-949.B01  Page 5 of 8

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

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