AD7575

–4–

REV. B

TERMINOLOGY

LEAST SIGNIFICANT BIT (LSB)

An ADC with 8-bits resolution can resolve 1 part in 2

256) of full scale. For the AD7575 with +2.46 V full-scale one

LSB is 9.61 mV.

TOTAL UNADJUSTED ERROR

This is a comprehensive specification that includes full-scale

error, relative accuracy and offset error.

RELATIVE ACCURACY

Relative Accuracy is the deviation of the ADC’s actual code

transition points from a straight line drawn between the devices

measured first LSB transition point and the measured full-scale

transition point.

SNR

Signal-to-Noise Ratio (SNR) is the ratio of the desired signal to

the noise produced in the sampled and digitized analog signal.

SNR is dependent on the number of quantization levels used in

the digitization process; the more levels, the smaller the quantiza-

tion noise. The theoretical SNR for a sine wave input is given by

SNR = (6.02 N + 1.76) dB

where N is the number of bits in the ADC.

FULL-SCALE ERROR (GAIN ERROR)

The gain of a unipolar ADC is defined as the difference between

the analog input levels required to produce the first and the last

digital output code transitions. Gain error is a measure of the

deviation of the actual span from the ideal span of FS – 2 LSBs.

ANALOG INPUT RANGE

is 0 V to +2.46 V. The output data in LSBs is related to the

analog input voltage by the integer value of the following

expression:

Data (LSBs) =

256 AIN

+ 0.5

SLEW RATE

Slew Rate is the maximum allowable rate of change of input

signal such that the digital sample values are not in error. Slew

Rate limitations may restrict the analog signal bandwidth for

full-scale analog signals below the bandwidth allowed from

sampling theorem considerations.

ORDERING GUIDE

Relative

Temperature

Accuracy

Package

Model

1

Range

(LSB)

Options

2

AD7575JR

0

°C to +70°C

±1 max

R-18

AD7575JN

0

°C to +70°C

±1 max

N-18

AD7575KN

0

°C to +70°C

±1/2 max

N-18

AD7575JP

0

°C to +70°C

±1 max

P-20A

AD7575KP

0

°C to +70°C

±1/2 max

P-20A

AD7575AQ

–25

°C to +85°C

±1 max

Q-18

AD7575BQ

–25

°C to +85°C

±1/2 max

Q-18

AD7575SQ

–55

°C to +125°C

±1 max

Q-18

AD7575TQ

–55

°C to +125°C

±1/2 max

Q-18

AD7575SE

–55

°C to +125°C

±1 max

E-20A

AD7575TE

–55

°C to +125°C

±1/2 max

E-20A

NOTES

Contact local sales office for military data sheet. For U.S. Standard Military

Drawing (SMD), see DESC drawing #5962-87762.

Carrier; Q = Cerdip, R = SOIC.

PIN CONFIGURATIONS

PLCC

DIP/SOIC

LCCC

TOP VIEW

(Not to Scale)

18

17

16

15

14

13

12

11

10

1

2

3

4

5

6

7

8

9

AD7575

DGND

DB5

CS

RD

TP

BUSY

DB6

DB7 (MSB)

CLK

DB4

DB3

AIN

AGND

DB2

DB1

DB0 (LSB)

TOP VIEW

(Not to Scale)

20 19

1

2

3

18

14

15

16

17

4

5

6

7

8

9

10 111213

NC = NO CONNECT

BUSY

CLK

DB7 (MSB)

DB6

DB5

AIN

AGND

DB0 (LSB)

DB1

DB2

AD7575

3

2

1

20

19

9

10

11

12

13

18

17

16

15

14

4

5

6

7

8

TOP VIEW

(Not to Scale)

PIN 1

IDENTIFIER

NC = NO CONNECT

TP

BUSY

CLK

DB7 (MSB)

DB6

AIN

AGND

DB0 (LSB)

DB1

DB2

AD7575