ISL26321 datasheet(13/23 Pages) INTERSIL

13 / 23 page

ISL26320, ISL26321, ISL26322, ISL26323, ISL26324, ISL26325, ISL26329

FN8273.0

June 8, 2012

Analog Inputs

Some members of the ISL26320/21/22/23/24/25/29 family

feature a fully differential input with a nominal full-scale range

equal to twice the applied VREF voltage. Those devices with

differential inputs have a nominal full scale range equal to twice

the applied VREF voltage. Each input swings VREF volts (peak-to-

peak), 180° out of phase from one another for a total differential

input of 2*VREF (refer to Figures 23 and 24).

Differential signaling offers several benefits over a single-ended

input, such as:

• Doubling of the full-scale input range (and therefore the

dynamic range)

• Improved even order harmonic distortion

• Better noise immunity due to common mode rejection

Figure 24 shows the relationship between the reference voltage

and the full-scale differential input range for two different values

of VREF. Note that the common-mode input voltage must be

maintained within ±200mV of VREF/2 for differential inputs.

Those devices with singled-ended inputs have a ground-

referenced peak-to-peak input voltage span equal to the

reference voltage.

FIGURE 21. IDEAL TRANSFER CHARACTERISTICS, DIFFERENTIAL INPUT

FIGURE 22. IDEAL TRANSFER CHARACTERISTICS, SINGLE-ENDED INPUT

FIGURE 23. DIFFERENTIAL INPUT SIGNALING

FIGURE 24. RELATIONSHIP BETWEEN VREF AND FULL-SCALE

RANGE FOR DIFFERENTIAL INPUTS

ISL26321 Datasheet(PDF) 13 Page - Intersil Corporation