Electronic Components Datasheet Search |
|
WM0834 Datasheet(PDF) 11 Page - Wolfson Microelectronics plc |
|
WM0834 Datasheet(HTML) 11 Page - Wolfson Microelectronics plc |
11 / 16 page Wolfson Microelectronics 11 WM0834, WM0838 Functional Description (continued) WM0834 MUX Addressing MUX Address Channel Number SGL/DIF ODD/EVEN Select bit 0 1 2 3 Differential MUX Mode (Between adjacent pairs of points) 00 0 + - 00 1 + - 01 0 - + 01 1 - + Single Ended MUX Mode (between selected input(s) and AGND) 10 0 + 10 1 + 11 0 + 11 1 + Note: Analogue common input 'COM' used with single ended mode is internally tied to AGND All internal registers are cleared when CS is high. To initiate another conversion, CS must make a high to low transition and MUX address assignments input to DI. The DI inpit and DO output can be tied together and controlled via a bidirectional processor I/O bit line. Reference Input The analogue input voltage range Vmax to Vmin for differential and pseudo-differential input is defined by the voltage applied to the reference input with respect to AGND. WM0834/8 can be used in ratiometric appliacations or those requiring absolute accuracy. A ratiometric input is typically the Vcc and is the same supply used to power analogue input circuitry and sensors. In such systems under a given input condition, the same code will be output with variations in supply voltage, because the same ratio change occurs in both the analogue and reference input to the A/D. When used in applications requiring ab- solute accuracy, a suitable time and temperature stable voltage reference source should be used. The voltage source used to drive the reference input should be capable of driving the 2.4k Ω typical of the SAR resistor ladder. The maximum input voltage to the reference input is the Vcc supply voltage. The minimum can be as least as low as 1V to allow for direct conversion of sensor outputs with output voltage ranges less than 5V. Analogue Inputs While sampling the analogue inputs, short spikes of current enter a "+" input and flow out of the corresponding "-" input at the clock edges during conversion. This current does not cause errors as it decays rapidly and the internal comparator is strobed at the end of a clock period. Care should be exercised if bypass capacitors are used at the inputs as an apparant offset error can be caused by the capacitor averaging the input current and developing a volt- age across the source resistance. Bypass capacitors should not be used with a source resistance greater than 1k Ω. In considering error sources, input leakage current will also cause a voltage drop across the source resistance and hence, high impedance sources should be buffered. In differential mode, there is a 1/2 clock period interval between sampling the "+" and the "-" inputs. If there is a change in common mode voltage during this interval, an errorcould notionally result. For a sinusoidal common mode signal, the error is given by: VERROR = VPEAK (2 πfCM) (1/(2fCLK)) Where VPEAK = peak common mode voltage fCM = common mode signal frequency fCLK = clock frequency |
Similar Part No. - WM0834 |
|
Similar Description - WM0834 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |