6

REV. 1 June 2003

DATA SHEET

SPT5240

Specification Definitions

Differential Linearity Error (DLE) or

Differential Nonlinearity (DNL)

In an ideal DAC, output transitions between two adjacent

codes are 1 LSB apart. Differential Linearity Error is the

deviation, expressed in LSBs, from this ideal value.

Integral Linearity Error (ILE) or

Integral Nonlinearity (INL)

The ideal transfer for a DAC is a straight line drawn between

"zero-scale" output and "full-scale" output. ILE is the

deviation of the output from the straight line. The deviation

of the output at each code is measured and compared to the

ideal output at that code. ILE may also be expressed as a

sum of DLE starting from code 0…0 to the code that ILE

measurement is desired.

Monotonic

A digital-to-analog converter is considered monotonic if

the analog output never decreases as the code value at the

input increases. A DLE less than -1 LSB would indicate a

non-monotonic DAC.

Offset Error

The deviation, from ideal, at the DAC output when set to

zero-scale. In the current output DAC there should be no

current flow at zero-scale. Therefore, Offset Error is the

amount of current measured with the DAC set to zero-scale.

Full-Scale Error

The ideal maximum full-scale current output of the DAC is

deviation of the output from ideal with the offset error

included.

Gain Error

The ideal maximum full-scale current output of the DAC is

of the output from ideal with the offset error removed.

Full-Scale Output

The maximum current output available for a given value of

Zero-Scale Output

The minimum current output, ideally zero amps. In the

is zero-scale at code 1111111111.

Compliance Voltage

The maximum terminal output voltage for which the device

will provide the specified current output characteristics.

Harmonic

1. Of a sinusoidal wave, an integer multiple of the frequency

of the wave. Note: The frequency of the sine wave is called

the fundamental frequency or the first harmonic, the

second harmonic is twice the fundamental frequency, the

third harmonic is three times the fundamental frequency, etc.

2. Of a periodic signal or other periodic phenomenon, such

as an electromagnetic wave or a sound wave, a component

frequency of the signal that is an integer multiple of the

fundamental frequency. Note: The fundamental frequency

is the reciprocal of the period of the periodic phenomenon.

Total Harmonic Distortion (THD)

The ratio of the sum of the power of first 9 harmonics above

the fundamental frequency to the power of the fundamental

frequency. Usually expressed in dBc.

Spurious Free Dynamic Range (SFDR)

The ratio of the fundamental sinusoidal power to the power

of the single largest harmonic or spurious signal within the

range of the 9th harmonic.

Clock Feedthrough

The ratio of the full-scale output to the peak-to-peak noise

generated at the DAC output by input clock transitions.

Expressed in dBFS.

Major Code Transition

The DAC code transition between 011…1 and 100…0 is

referred to as major code transition. This transition often

involves maximum number of internal circuit elements to

switch states, resulting in worst DLE, ILE, glitch, etc.

Glitch Energy

A glitch is a switching transient that appears in the output of

a DAC during a code transition. Glitch energy is measured as

a product of the output voltage and time duration for major

code transition, expressed in pV-s.

Output Rise Time

The amount of time for the output to change from 10%

to 90% of the full-scale voltage, for a positive full scale

transition from zero-scale to full-scale.

Output Fall Time

The amount of time for the output to change from 90%

to 10% of the full-scale voltage, for a negative full scale

transition from full-scale to zero-scale.