®

DAC2813

6

SETTLING TIME

Settling Time is the total time (including slew time) for the

output to settle to within an error band around its final value

after a change in input. Settling times are specified to

±0.01% of Full Scale Range (FSR) for two conditions: one

for a FSR output change of 20V (25k

Ω feedback) and one

for a 1LSB change. The 1LSB change is measured at the

Major Carry (7FF

input code transition at which worst-case settling time oc-

curs.

OPERATION

INTERFACE LOGIC

The bus interface logic of the DAC2813 consists of two

independently addressable latches in two ranks for each

D/A converter. The first rank consists of one 12-bit input

latch which can be loaded directly from a 12- or 16-bit

microprocessor/microcontroller bus. The input latch holds

data temporarily before it is loaded into the second latch, the

D/A latch. This double buffered organization permits simul-

taneous update of all D/As.

All latches are level-triggered. Data present when the con-

trol signals are logic “0” will enter the latch. When the

control signals return to logic “1”, the data is latched.

CAUTION: DAC2813 was designed to use WR as the fast

strobe. WR/ has a much faster logic path than EN

LDAC). Therefore, if one permanently wires WR to DCOM

and uses only EN

At T

DISCUSSION OF

SPECIFICATIONS

LINEARITY ERROR

Linearity error is defined as the deviation of the analog

output from a straight line drawn between the end points

(digital inputs all “1s” and all “0s”). DAC2813 linearity

error is

DIFFERENTIAL LINEARITY ERROR

Differential Linearity Error (DLE) is the deviation from a

1LSB output change from one adjacent state to the next. A

DLE specification of 1/2LSB means that the output step size

can range from 1/2LSB to 3/2LSB when the digital input

code changes from one code word to the adjacent code word

If the DLE is more positive than –1LSB, the D/A is said to

be monotonic.

MONOTONICITY

A D/A converter is monotonic if the output either increases

or remains the same for increasing digital input values.

DAC2813 is monotonic over their specification temperature

DRIFT

Gain Drift is a measure of the change in the Full Scale

Range (FSR) output over the specification temperature range.

Gain Drift is expressed in parts per million per degree

Bipolar Zero Drift is measured with a data input of 800

HEX

.

The D/A is configured for bipolar output. Bipolar Zero Drift

is expressed in parts per million of Full Scale Range per

20

10

0

–10

–20

–2

Time (µs)

SETTLING TIME, +10V TO –10V

+5

0

0

2

4

6

8

10

12

1LSB = 4.88mV

V

OUT

WR

V

OUT

20

10

0

–10

–20

–40

–2

Time (µs)

SETTLING TIME, –10V TO +10V

+5

0

02468

10

12

14

V

OUT

WR

V

OUT

1LSB = 4.88mV