EVAL-ADXRS620Z Analog Devices Inc, EVAL-ADXRS620Z Datasheet - Page 10

• Manufacturer Part Number: EVAL-ADXRS620Z
• Description: EB ?300?/sec Yaw Rate Gyroscope
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADXRS620Z

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADXRS620
ADXRS620 AND SUPPLY RATIOMETRICITY
The ADXRS620 RATEOUT and TEMP signals are ratiometric
to the V
temperature outputs are proportional to V
ADXRS620 is most easily used with a supply-ratiometric ADC
that results in self-cancellation of errors due to minor supply
variations. There is some small error due to nonratiometric
behavior. Typical ratiometricity error for null, sensitivity, self-
test, and temperature output is outlined in Table 4.
Note that V
Table 4. Ratiometricity Error for Various Parameters
Parameter
ST1
ST2
Null
Sensitivity
V
TEMP
Mean
Sigma
Mean
Sigma
Mean
Sigma
Mean
Sigma
Mean
Sigma
RATIO
RATIO
voltage, that is, the null voltage, rate sensitivity, and
V
0.3%
0.21%
−0.15%
0.22%
−0.3%
0.2%
0.003%
0.06%
−0.2%
0.05%
must never be greater than AV
S
= V
RATIO
= 4.85 V
V
0.09%
0.19%
−0.2%
0.2%
−0.05%
0.08%
−0.25%
0.06%
−0.04%
0.06%
RATIO
S
= V
. Thus, the
CC.
RATIO
= 5.15 V
Rev. B | Page 10 of 12
NULL ADJUSTMENT
The nominal 2.5 V null is for a symmetrical swing range at
RATEOUT (1B, 2A). However, a nonsymmetrical output swing
may be suitable in some applications. Null adjustment is possible
by injecting a suitable current to SUMJ (1C, 2C). Note that supply
disturbances may reflect some null instability. Digital supply
noise should be avoided, particularly in this case.
SELF-TEST FUNCTION
The ADXRS620 includes a self-test feature that actuates each of
the sensing structures and associated electronics as if subjected
to angular rate. It is activated by standard logic high levels applied
to Input ST1 (5F, 5G), Input ST2 (4F, 4G), or both. ST1 causes
the voltage at RATEOUT to change about −0.450 V, and ST2
causes an opposite change of +0.450 V. The self-test response
follows the viscosity temperature dependence of the package
atmosphere, approximately 0.25%/°C.
Activating both ST1 and ST2 simultaneously is not damaging.
ST1 and ST2 are fairly closely matched (±5%), but actuating
both simultaneously may result in a small apparent null bias
shift proportional to the degree of self-test mismatch.
ST1 and ST2 are activated by applying a voltage equal to V
to the ST1 and ST2 pins. The voltage applied to ST1 and ST2
must never be greater than AV
CONTINUOUS SELF-TEST
The on-chip integration of the ADXRS620 gives it higher reliability
than is obtainable with any other high volume manufacturing
method. In addition, it is manufactured under a mature BiMOS
process with field-proven reliability. As an additional failure
detection measure, a power-on self-test can be performed.
However, some applications may warrant continuous self-test
while sensing rate. Details outlining continuous self-test techniques
are also available in the
AN-768
CC
Application Note at analog.com.
.
RATIO