AFS090 datasheet(102/334 Pages) MICROSEMI

102 / 334 page

Device Architecture

2- 86

R e visio n 2

Terminology

BW – Bandwidth

BW is a range of frequencies that a Channel can handle.

Channel

A channel is define as an analog input configured as one of the Prescaler range shown in Table 2-57 on

page 2-132. The channel includes the Prescaler circuit and the ADC.

Channel Gain

Channel Gain is a measured of the deviation of the actual slope from the ideal slope. The slope is

measured from the 20% and 80% point.

EQ 1

Channel Gain Error

Channel Gain Error is a deviation from the ideal slope of the transfer function. The Prescaler Gain Error

is expressed as the percent difference between the actual and ideal, as shown in EQ 2.

EQ 2

Channel Input Offset Error

Channel Offset error is measured as the input voltage that causes the transition from zero to a count of

one. An Ideal Prescaler will have offset equal to ½ of LSB voltage. Offset error is a positive or negative

when the first transition point is higher or lower than ideal. Offset error is expressed in LSB or input

voltage.

Total Channel Error

Total Channel Error is defined as the total error measured compared to the ideal value. Total Channel

Error is the sum of gain error and offset error combined. Figure 2-66 shows how Total Channel Error is

measured.

Total Channel Error is defined as the difference between the actual ADC output and ideal ADC output. In

the example shown in Figure 2-66, the Total Channel Error would be a negative number.

Figure 2-66 • Total Channel Error Example

Gain

Gainactual

Gainideal

-------------------------

ErrorGain

(1-Gain) 100%

Input Voltage to Prescaler

T otal C hannel Error

C hannel Gain

Actual Output

Channel Input

Offset Error

AFS090 Datasheet(PDF) 102 Page - Microsemi Corporation