Zakładka z wyszukiwarką danych komponentów |
|
ADXRS300 Arkusz danych(PDF) 6 Page - Analog Devices |
|
ADXRS300 Arkusz danych(HTML) 6 Page - Analog Devices |
6 / 8 page ADXRS300 between the RATEOUT (1B, 2A) and SUMJ (1C, 2C) pins will result in ( ) ( ) EXT EXT OUT R k / R k R × × = Ω 180 Ω 180 The –3 dB frequency is set by RSEN (the parallel combination of RSEN1 and RSEN2) at about 3.5 kΩ nominal; CMID is less well controlled since RSEN1 and RSEN2 have been used to trim the rate sensitivity during manufacturing and have a ±35% tolerance. Its primary purpose is to limit the high frequency demodulation artifacts from saturating the final amplifier stage. Thus, this pole of nominally 400 Hz @ 0.1 µF need not be precise. Lower fre- quency is preferable, but its variability usually requires it to be about 10 times greater (in order to preserve phase integrity) than the well-controlled output pole. In general, both –3 dB filter frequencies should be set as low as possible to reduce the amplitude of these high frequency artifacts and to reduce the overall system noise. Increasing Measurement Range The full-scale measurement range of the ADXRS300 can be increased by placing an external resistor between the RATE- OUT (1B, 2A) and SUMJ (1C, 2C) pins, which would parallel the internal ROUT resistor that is factory-trimmed to 180 kΩ. For example, a 330 kΩ external resistor will give ~50% increase in the full-scale range. This is effective for up to a 4× increase in the full-scale range (minimum value of the parallel resistor allowed is 45 kΩ). Beyond this amount of external sensitivity reduction, the internal circuitry headroom requirements prevent further increase in the linear full-scale output range. The drawbacks of modifying the full-scale range are the addi- tional output null drift (as much as 2°/sec over temperature) and the readjustment of the initial null bias (see the Null Adjust section). Using the ADXRS300 with a Supply- Ratiometric ADC The ADXRS300’s RATEOUT signal is nonratiometric, i.e., nei- ther the null voltage nor the rate sensitivity is proportional to the supply. Rather they are nominally constant for dc supply changes within the 4.75 V to 5.25 V operating range. If the ADXRS300 is used with a supply-ratiometric ADC, the ADXRS300’s 2.5 V output can be converted and used to make corrections in software for the supply variations. Null Adjust Null adjustment is possible by injecting a suitable current to SUMJ (1C, 2C). Adding a suitable resistor to either ground or to the positive supply is a simple way of achieving this. The nomi- nal 2.5 V null is for a symmetrical swing range at RATEOUT (1B, 2A). However, a nonsymmetric output swing may be suit- able in some applications. Note that if a resistor is connected to the positive supply, then supply disturbances may reflect some null instabilities. Digital supply noise should be avoided particularly in this case (see the Supply and Common Considerations section). The resistor value to use is approximately ) V – )/(V ( R NULL NULL NULL 1 0 000 , 180 5 . 2 × = VNULL0 is the unadjusted zero rate output, and VNULL1 is the target null value. If the initial value is below the desired value, the resistor should terminate on common or ground. If it is above the desired value, the resistor should terminate on the 5 V sup- ply. Values are typically in the 1 MΩ to 5 MΩ range. If an external resistor is used across RATEOUT and SUMJ, then the parallel equivalent value is substituted into the above equa- tion. Note that the resistor value is an estimate since it assumes VCC = 5.0 V and VSUMJ = 2.5 V. Self-Test Function The ADXRS300 includes a self-test feature that actuates each of the sensing structures and associated electronics in the same manner as if subjected to angular rate. It is activated by standard logic high levels applied to inputs ST1 (5F, 5G), ST2 (4F, 4G), or both. ST1 will cause a voltage at RATEOUT equivalent to typi- cally –270 mV and ST2 will cause an opposite +270 mV change. The self-test response follows the viscosity temperature depend- ence of the package atmosphere, approximately 0.25%/°C. Activating both ST1 and ST2 simultaneously is not damaging. Since ST1 and ST2 are not necessarily closely matched, actuat- ing both simultaneously may result in an apparent null bias shift. Continuous Self-Test The one-chip integration of the ADXRS300 gives it higher reli- ability than is obtainable with any other high volume manufac- turing method. Also, it is manufactured under a mature BIMOS process that has field-proven reliability. As an additional failure detection measure, power-on self-test can be performed. How- ever, some applications may warrant continuous self-test while sensing rate. Application notes outlining continuous self-test techniques are also available on the Analog Devices website. Rev. A | Page 6 of 8 |
Podobny numer części - ADXRS300 |
|
Podobny opis - ADXRS300 |
|
|
Link URL |
Polityka prywatności |
ALLDATASHEET.PL |
Czy Alldatasheet okazała się pomocna? [ DONATE ] |
O Alldatasheet | Reklama | Kontakt | Polityka prywatności | Linki | Lista producentów All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |