AD5545 datasheet(14/25 Pages) AD

14 / 25 page

AD5405

Rev. B | Page 13 of 24

TERMINOLOGY

Relative Accuracy (Endpoint Nonlinearity)

A measure of the maximum deviation from a straight line

passing through the endpoints of the DAC transfer function. It

is measured after adjusting for zero and full scale and is normally

expressed in LSBs or as a percentage of the full-scale reading.

Differential Nonlinearity

The difference in the measured change and the ideal 1 LSB

change between two adjacent codes. A specified differential

nonlinearity of −1 LSB maximum over the operating temper-

ature range ensures monotonicity.

Gain Error (Full-Scale Error)

A measure of the output error between an ideal DAC and the

actual device output. For this DAC, ideal maximum output is

VREF − 1 LSB. The gain error of the DAC is adjustable to zero

with an external resistance.

Output Leakage Current

The current that flows into the DAC ladder switches when they

are turned off. For the IOUT1 terminal, it can be measured by

loading all 0s to the DAC and measuring the IOUT1 current.

Minimum current flows into the IOUT2 line when the DAC is

loaded with all 1s.

Output Capacitance

Capacitance from IOUT1 or IOUT2 to AGND.

Output Current Settling Time

The amount of time for the output to settle to a specified level

for a full-scale input change. For this device, it is specified with

a 100 Ω resistor to ground.

Digital-to-Analog Glitch Impulse

The amount of charge injected from the digital inputs to the

analog output when the inputs change state. This is typically

specified as the area of the glitch in either pA-sec or nV-sec,

depending on whether the glitch is measured as a current or

voltage signal.

Digital Feedthrough

When the device is not selected, high frequency logic activity

on the device’s digital inputs is capacitively coupled through the

device and produces noise on the IOUT pins and, subsequently,

on the following circuitry. This noise is digital feedthrough.

Multiplying Feedthrough Error

The error due to capacitive feedthrough from the DAC

reference input to the DAC IOUT1 terminal when all 0s are

loaded to the DAC.

Digital Crosstalk

The glitch impulse transferred to the outputs of a DAC in

response to a full-scale code change (all 0s to all 1s, or vice

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

nV-sec.

Analog Crosstalk

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, or vice versa) while keeping LDAC high and then pulsing

LDAC low and monitoring the output of the DAC whose digital

code has not changed. The area of the glitch is expressed in nV-sec.

Channel-to-Channel Isolation

The portion of input signal from a DAC’s reference input that

appears at the output of the other DAC. It is expressed in decibels.

Total Harmonic Distortion (THD)

The DAC is driven by an ac reference. The ratio of the rms sum

of the harmonics of the DAC output to the fundamental value is

the THD. Usually only the lower-order harmonics are included,

such as the second to the fifth harmonics.

log

THD

Intermodulation Distortion (IMD)

The DAC is driven by two combined sine wave references

of frequencies fa and fb. Distortion products are produced

at sum and difference frequencies of mfa ± nfb, where m, n = 0,

1, 2, 3 ... Intermodulation terms are those for which m or n is

not equal to 0. The second-order terms include (fa + fb) and

(fa − fb), and the third-order terms are (2fa + fb), (2fa − fb),

(f + 2fa + 2fb), and (fa − 2fb). IMD is defined as

(

)

fundamenta

the

amplitude

rms

products

distortion

diff

and

sum

the

sum

rms

IMD

log

Compliance Voltage Range

The maximum range of (output) terminal voltage for which the

device provides the specified characteristics.

AD5545 Scheda tecnica(PDF) 14 Page - Analog Devices

AD5545 Scheda tecnica(HTML) 14 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Scheda tecnica Scarica

Link URL