Motore di ricerca datesheet componenti elettronici |
|
AD7243BR Scheda tecnica(PDF) 5 Page - Analog Devices |
|
AD7243BR Scheda tecnica(HTML) 5 Page - Analog Devices |
5 / 12 page REV. A –5– AD7243 TERMINOLOGY (Continued) This “knee” is an offset effect, not a linearity error, and the transfer function would have followed the dotted line if the out- put voltage could have gone negative. Normally, linearity is measured between zero (all 0s input code) and full scale (all 1s input code) after offset and full scale have been adjusted out or allowed for, but this is not possible in single supply operation if the offset is negative, due to the knee in the transfer function. Instead, linearity of the AD7243 in the unipolar mode is measured between full scale and the lowest code which is guaranteed to produce a positive output voltage. This code is calculated from the maximum specification for negative offset. For the A and B versions the linearity is mea- sured between Codes 3 and 4095. For the S grade, linearity is measured between Code 5 and Code 4095. Differential Nonlinearity Differential Nonlinearity is the difference between the measured change and the ideal 1 LSB change between any two adjacent codes. A specified differential nonlinearity of ±1 LSB or less over the operating temperature range ensures monotonicity. Unipolar Offset Error Unipolar Offset Error is the measured output voltage from VOUT with all zeros loaded into the DAC latch when the DAC is configured for unipolar output. It is due to a combination of the offset errors in the DAC and output amplifier. PIN CONFIGURATION DIP and SOIC TOP VIEW (Not to Scale) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 16 15 REFIN REFOUT CLR BIN/COMP SCLK SDIN SYNC DGND AGND SDO DCEN LDAC VDD VSS VOUT ROFS AD7243 CIRCUIT INFORMATION D/A Section The AD7243 contains a 12-bit voltage mode D/A converter consisting of highly stable thin film resistors and high speed NMOS single-pole, double-throw switches. The output voltage from the converter has the same polarity as the reference volt- age, REFIN, allowing single supply operation. SHOWN FOR ALL 1S ON DAC *BUFFERED REFIN VOLTAGE 2R 2R R R R R R 2R 2R 2R 2R 2R 2R DB0 DB1 DB9 DB10 DB11 REFIN* AGND R OFS VOUT Figure 2. D/A Simplified Circuit Diagram Internal Reference The AD7243 has an on-chip temperature compensated buried Zener reference which is factory trimmed to 5 V ± 50 mV. The reference voltage is provided at the REFOUT pin. This refer- ence can be used to provide the reference voltage for the D/A converter (by connecting the REFOUT pin to the REFIN pin.) The reference voltage can also be used as a reference for other components and is capable of providing up to 500 µA to an ex- ternal load. The maximum recommended capacitance on REFOUT for normal operation is 50 pF. If the reference is re- quired for external use with capacitive loads greater than 50 pF then it should be decoupled to AGND with a 200 Ω resistor in series with a parallel combination of a 10 µF tantalum capacitor and a 0.1 µF ceramic capacitor. 200 10 F 0.1 F REFOUT EXT LOAD Figure 3. Reference Decoupling Scheme External Reference In some applications, the user may require a system reference or some other external reference to drive the AD7243. References such as the AD586 provide an ideal external reference source (see Figure 10). The REFIN voltage is internally buffered by a unity gain amplifier before being applied to the D/A converter. The D/A converter is scaled for a 5 V reference and the device is tested with 5 V applied to REFIN. Other reference voltages may be used with degraded performance. Figure 4 shows the typical degradation in linearity vs. REFIN. REFIN – Volts 1.0 2 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 3 4567 8 9 VDD = +15V VSS = –15V TA = +25 C INL DNL Figure 4. Typical Linearity vs. REFIN Voltage Op Amp Section The output of the voltage mode D/A converter is buffered by a noninverting CMOS amplifier. The ROFS input allows three out- put voltage ranges to be selected. The buffer amplifier is capable of developing +10 V across a 2 k Ω load to AGND. The output amplifier can be operated from a single +12 V to +15 V supply by tying VSS = 0 V. The amplifier can also be operated from dual supplies to allow an additional bipolar output range of –5 V to +5 V. Dual supplies are necessary for the bipolar output range but can also be used for the unipolar ranges to give faster settling time to voltages near |
Codice articolo simile - AD7243BR |
|
Descrizione simile - AD7243BR |
|
|
Link URL |
Privacy Policy |
ALLDATASHEETIT.COM |
Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | scambio Link | Ricerca produttore 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 |