AD9262EBZ datasheet(25/32 Pages) AD

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AD9262

Rev. A | Page 25 of 32

Table 20 shows the corresponding threshold level in dBFS vs.

is set. In the case where 0x111[5:0] is set to all 0s, the threshold

level is set to the maximum code of 32,76710. This feature pro-

vides a means of reporting the instantaneous amplitude as it

crosses a user-provided threshold. This gives the user a sense

of the signal level without needing to perform a full power

measurement.

The user has the ability to select how the overrange conditions

are reported, and this is controlled through Register 0x111 via

AUTORST, OR_IND, and ORTHRESH (see Table 21). By

enabling the AUTORST bit, Register 0x111[7], if an overrange

occurs, the ADC automatically resets itself. The ORx pins remain

high until the automatic reset has completed. If an analog trip

occurs, the modulator resets itself after 16 consecutive clock

cycles of overrange.

If the AD9262 is used in a system that incorporates automatic

gain control (AGC), the ORx signal can be used to indicate that

the signal amplitude should be reduced. This may be particularly

effective for use in maximizing the signal dynamic range if the

signal includes high occurrence components that occasionally

exceed full scale by a small amount.

TIMING

The AD9262 provides a data clock out (DCO) pin to assist in

capturing the data in an external register. The data outputs are

valid on the rising edge of DCO, unless changed by setting

Serial Register 0x16[7] (see the Serial Port Interface (SPI)

section). See Figure 2 for a graphical timing description.

Table 20. OR Threshold Levels

0x111[5:0]

Threshold (dBFS)

0x111[5:0]

Threshold (dBFS)

0x111[5:0]

Threshold (dBFS)

−36.12

−9.28

−3.45

−30.10

−8.89

−3.25

−26.58

−8.52

−3.06

−24.08

−8.16

−2.87

−22.14

−7.82

−2.68

−20.56

−7.50

−2.50

−19.22

−7.18

−2.32

−18.06

−6.88

−2.14

−17.04

−6.58

−1.97

−16.12

−6.30

−1.80

−15.29

−6.02

−1.64

−14.54

−5.75

−1.48

−13.84

−5.49

−1.32

−13.20

−5.24

−1.16

−12.60

−5.00

−1.00

−12.04

−4.76

−0.86

−11.51

−4.53

−0.71

−11.02

−4.30

−0.56

−10.56

−4.08

−0.42

−10.10

−3.87

−0.28

−9.68

−3.66

−0.14

Table 21. ORx Conditions

ORx Conditions

AUTORST

OR_IND

ORTHRESH[5:0]

ORTHRESH[4:0]

Description

Normal, Reset Off

00000

Digital trip: if 16-bit output > 32,767, ORx = 1, else ORx = 0

Digital Threshold,

Reset Off

Digital threshold: if 16-bit output > ORTHRESH, ORx = 1,

else ORx = 0

Full Overrange,

Reset Off

If analog trip or digital trip, ORx = 1, else ORx = 0

Data Valid, No Reset

If analog trip or digital trip or calibration, ORx = 0, else ORx = 1

Normal, Reset On

00000

Digital trip: if 16-bit output > 32,767, ORx = 1, else ORx = 0

Digital Threshold,

Reset On

Digital threshold: if 16-bit output > ORTHRESH, ORx = 1,

else ORx = 0

Full Overrange,

Reset On

If analog trip or digital trip ORx = 1 else ORx = 0

Data Valid,

Reset On

If analog trip or digital trip or calibration, ORx = 0 else ORx = 1

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