AD5628 datasheet(12/24 Pages) AD

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AD5628/AD5648/AD5668

Preliminary Technical Data

Rev.PrA | Page 12 of 24

taking the various offset and gain errors into account. A typical

TUE vs. code plot can be seen in Figure 4.

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 secs and

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

major carry transition (7FFF Hex to 8000 Hex). See Figure 19.

DC Power Supply Rejection Ratio (PSRR)

This indicates how the output of the DAC is affected by changes in

the supply voltage. PSRR is the ratio of the change in VOUT

to a change in VDD for full-scale output of the DAC. It is

measured in dB. VREF is held at 2 V and VDD is varied ±10%.

DC Crosstalk

This is the dc change in the output level of one DAC in response to

a change in the output of another DAC. It is measured with a full-

scale output change on one DAC while monitoring another DAC

kept at midscale. It is expressed in µV.

Reference Feedthrough

This is the ratio of the amplitude of the signal at the DAC output to

the reference input when the DAC output is not being updated

(i.e., LDAC is high). It is expressed in dB.

Channel-to-Channel Isolation

This is the ratio of the amplitude of the signal at the output of one

DAC to a sine wave on the reference input of another DAC. It is

measured in dB.

Major-Code Transition Glitch Energy

Major-code transition glitch energy is the energy of the impulse

injected into the analog output when the 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 code is changed by 1 LSB at

the major carry transition (011 . . . 11 to 100 . . . 00 or 100 . . . 00 to

011 . . . 11).

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into the

analog output of a DAC from the digital input pins of the device,

but is measured when the DAC is not being written to (SYNC held

high). It is specified in nV-s and is measured with a fullscale

change on the digital input pins, i.e., from all 0s to all 1s and vice

versa.

Digital Crosstalk

This is the glitch impulse transferred to the output of one DAC at

midscale in response to a full-scale code change (all 0s to all 1s and

vice versa) in the input register of another DAC. It is measured in

standalone mode and is expressed in nV-s.

Analog Crosstalk

This is the glitch impulse transferred to the output of one DAC due

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

loading one of the input registers with a full-scale code change (all

0s to all 1s and vice versa) while keeping LDAC high. Then pulse

LDAC low and monitor the output of the DAC whose digital code

was not changed. The area of the glitch is expressed in nV-s.

DAC-to-DAC Crosstalk

This is the glitch impulse transferred to the output of one DAC due

to a digital code change and subsequent output change of another

DAC. This includes both digital and analog crosstalk. It is

measured by loading one of the DACs with a full-scale code change

(all 0s to all 1s and vice versa) with LDAC low and monitoring the

output of another DAC. The energy of the glitch is expressed in

nV-s.

Multiplying Bandwidth

The amplifiers within the DAC have a finite bandwidth. The

multiplying bandwidth is a measure of this. A sine wave on the

reference (with full-scale code loaded to the DAC) appears on the

output. The multiplying bandwidth is the frequency at which the

output amplitude falls to 3 dB below the input.

Total Harmonic Distortion

This is the difference between an ideal sine wave and its attenuated

version using the DAC. The sine wave is used as the reference for

the DAC, and the THD is a measure of the harmonics present on

the DAC output. It is measured in dB.

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