AD7302

–6–

REV. 0

TERMINOLOGY

INTEGRAL NONLINEARITY

For the DACs, relative accuracy or endpoint nonlinearity is a

measure of the maximum deviation, in LSBs, from a straight

line passing through the endpoints of the DAC transfer function.

A graphical representation of the transfer curve is shown in

Figure 14.

DIFFERENTIAL NONLINEARITY

Differential Nonlinearity is the difference between the measured

change and the ideal 1 LSB change between any two adjacent

codes. A specified differential nonlinearity of

±1 LSB maximum

ensures monotonicity.

ZERO CODE ERROR

either DAC when zero code (all zeros) is loaded to the DAC

latch. It is due to a combination of the offset errors in the DAC

and output amplifier. Zero scale error is expressed in LSBs.

GAIN ERROR

This is a measure of the span error of the DAC. It is the deviation

in slope of the DAC transfer characteristic from ideal, expressed

as a percent of the full-scale value. It includes full-scale errors

but not offset errors.

DIGITAL-TO-ANALOG GLITCH IMPULSE

Digital-to-Analog Glitch Impulse is the impulse injected into the

analog output when the digital inputs change state with the

DAC selected and the

LDAC used to update the DAC. It is

normally specified as the area of the glitch in nV-s and is

measured when the digital input code is changed by 1 LSB at

the major carry transition.

DIGITAL FEEDTHROUGH

Digital Feedthrough is a measure of the impulse injected into

the analog output of a DAC from the digital inputs of the same

DAC, but is measured when the DAC is not updated. It is

specified in nV-s and measured with a full-scale code change on

the data bus, i.e., from all 0s to all 1s and vice versa.

DIGITAL CROSSTALK

Digital Crosstalk is the glitch impulse transferred to the output

of one converter due to a digital code change to another DAC.

It is specified in nV-s.

ANALOG CROSSTALK

Analog Crosstalk is a change in output of any DAC in response

to a change in the output of the other DAC. It is measured in

LSBs.

POWER SUPPLY REJECTION RATIO (PSRR)

This specification indicates how the output of the DAC is

affected by changes in the power supply voltage. Power supply

rejection ratio is quoted in terms of % change in output per %

±10%.