9

FN3096.6

August 7, 2008

Definitions of Specifications

Linearity Error

Linearity error refers to the deviation of each individual code

from a line drawn from “zero” through “full scale”. The point

the first code transition (all zeros to only the LSB “on”). “Full

transition (to all ones). The deviation of a code from the true

straight line is measured from the middle of each particular

code.

The HI-X74AK grade is guaranteed for maximum nonlinearity

which falls exactly in the center of a given code width will result

in the correct digital output code. Values nearer the upper or

lower transition of the code width may produce the next upper

or lower digital output code. The HI-X74AJ is guaranteed to

±1

LSB max error. For this grade, an analog value which falls

within a given code width will result in either the correct code for

that region or either adjacent one.

Note that the linearity error is not user-adjustable.

Differential Linearity Error (No Missing Codes)

A specification which guarantees no missing codes requires

that every code combination appear in a monotonic increasing

sequence as the analog input level is increased. Thus every

code must have a finite width. For the HI-X74AK grade, which

guarantees no missing codes to 12-bit resolution, all 4096

codes must be present over the entire operating temperature

ranges. The HI-X74AJ grade guarantees no missing codes to

11-bit resolution over temperature; this means that all code

combinations of the upper 11 bits must be present; in practice

very few of the 12-bit codes are missing.

Unipolar Offset

common. Unipolar offset is defined as the deviation of the

actual transition from that point. This offset can be adjusted as

discussed on the following pages. The unipolar offset

temperature coefficient specifies the maximum change of the

transition point over temperature, with or without external

adjustment.

Bipolar Offset

Similarly, in the bipolar mode, the major carry transition

(0111 1111 1111 to 1000 0000 0000) should occur for an

offset error and temperature coefficient specify the initial

deviation and maximum change in the error over

temperature.

Full Scale Calibration Error

The last transition (from 1111 1111 1110 to 1111 1111 1111)

nominal full scale (9.9963V for 10.000V full scale). The full

scale calibration error is the deviation of the actual level at

the last transition from the ideal level. This error, which is

typically 0.05 to 0.1% of full scale, can be trimmed out as

shown in Figures 1 and 2. The full scale calibration error

over temperature is given with and without the initial error

trimmed out. The temperature coefficients for each grade

indicate the maximum change in the full scale gain from the

initial value using the internal 10V reference.

Pin Descriptions

PIN

SYMBOL

DESCRIPTION

Logic supply pin (+5V)

2

12/8

Data Mode Select - Selects between

12-bit and 8-bit output modes.

3CS

Chip Select - Chip Select high disables

the device.

Byte Address/Short Cycle - See Table 3

for operation.

5R/C

Read/Convert - See Table 3 for operation.

6

CE

Chip Enable - Chip Enable low disables

the device.

Positive Supply (+12V/+15V)

8

REF OUT

+10V Reference

9

AC

Analog Common

10

REF IN

Reference Input

11

Negative Supply (-12V/-15V).

12

BIP OFF

Bipolar Offset

13

10V Input

10V Input - Used for 0V to 10V and -5V to

+5V input ranges.

14

20V Input

20V Input - Used for 0V to 20V and -10V to

+10V input ranges.

15

DC

Digital Common

16

DB0

Data Bit 0 (LSB)

17

DB1

Data Bit 1

18

DB2

Data Bit 2

19

DB3

Data Bit 3

20

DB4

Data Bit 4

21

DB5

Data Bit 5

22

DB6

Data Bit 6

23

DB7

Data Bit 7

24

DB8

Data Bit 8

25

DB9

Data Bit 9

26

DB10

Data Bit 10

27

DB11

Data Bit 11 (MSB)

28

STS

Status Bit - Status high implies a conversion

is in progress.

HI-574A, HI-674A