AD7294 Просмотр технического описания (PDF) - Analog Devices

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AD7294

12-Bit, Multichannel, DAC/ADC Temperature Sensor and Current Sense for Monitor and Control Applications

Analog Devices 

AD7294

TERMINOLOGY

Integral Nonlinearity

The maximum deviation from a straight line passing through

the endpoints of the ADC/DAC transfer function. The

endpoints are zero scale, a point 1 LSB. below the first code

transition, and full scale, a point 1 LSB above the last code

transition.

Differential Nonlinearity

Differential nonlinearity (DNL) 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.

Gain Error

Gain error 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 percentage of the full-scale range.

Gain Error Match

The difference in gain error between any two channels.

Zero-Code Error

Zero-code error is a measure of the output error when zero

code (0x000) is loaded into the DAC register. Ideally, the output

should be 0 V. Zero-code error is due to a combination of the

offset errors in the DAC and output amplifier. Zero-code error

is expressed in mV.

Full-Scale Error

Full-scale error is a measure of the output error when full-scale

code (0xFFFF) is loaded into the DAC register. Ideally, the output

should be VDD − 1 LSB. Full-scale error is expressed in mV.

Zero-Code Error Drift

Zero-code error drift is a measure of the change in zero-code

error with a change in temperature. It is expressed in µV/°C.

Gain Error Drift

Gain error drift is a measure of the change in gain error with

changes in temperature. It is expressed in (ppm of full-scale

range)/°C.

Preliminary Technical Data

Digital-to-Analog Glitch Impulse

Digital-to-analog glitch impulse is the impulse injected into the

analog output when the input code in the DAC register changes

state. 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 (0x2000 to 0x1FFF).

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into

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

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

It is specified in nV-s and is measured with a full-scale code

change on the data bus—from all 0s to all 1s or vice versa.

Channel-to-Channel Isolation

A measure of the level of crosstalk between channels, taken

by applying a full-scale sine wave signal to the unselected input

channels and determining how much of the 108 Hz signal is

attenuated in the selected channel. The sine wave signal applied

to the unselected channels is then varied from 1 kHz up to 2 MHz,

and each time it is determined how much of the 108 Hz signal

in the selected channel is attenuated. This figure represents the

worst-case level across all channels.

Aperture Delay

The measured interval between the sampling clock’s leading

edge and the point at which the ADC takes the sample.

Aperture Jitter

The sample-to-sample variation in the effective point in time at

which the sample is taken.

Offset Error

The deviation of the first code transition (00 … 000) to

(00 … 001) from the ideal—that is, AGND + 1 LSB.

Offset Error Match

The difference in offset error between any two channels.

Rev. PrB | Page 10 of 45

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