 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
AD5360 Datasheet(PDF) 18 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
AD5360 Datasheet(HTML) 18 Page - Analog Devices |
|
|
18 / 29 page  AD5360/AD5361 Rev. A | Page 17 of 28 OUTPUT AMPLIFIER Because the output amplifiers can swing to 1.4 V below the positive supply and 1.4 V above the negative supply, this limits how much the output can be offset for a given reference voltage. For example, it is not possible to have a unipolar output range of 20 V because the maximum supply voltage is ±16.5 V. CLR CLR CLR DAC CHANNEL OFFSET DAC OUTPUT R6 10kΩ R2 20kΩ S3 S2 S1 R4 60kΩ R3 20kΩ SIGGND SIGGND R5 60kΩ R1 20kΩ Figure 23. Output Amplifier and Offset DAC Figure 23 shows details of a DAC output amplifier and its connections to the offset DAC. On power-up, S1 is open, disconnecting the amplifier from the output. S3 is closed, so the output is pulled to SIGGND. S2 is also closed to prevent the output amplifier from being open-loop. If CLR is low at power-up, the output remains in this condition until CLR is taken high. The DAC registers can be programmed, and the outputs assume the programmed values when CLR is taken high. Even if CLR is high at power-up, the output remains in this condition until VDD > 6 V and VSS < −4 V and the initialization sequence has finished. The outputs then go to their power-on default values. TRANSFER FUNCTION The output voltage of a DAC in the AD5360/AD5361 is dependent on the value in the input register, the value of the M and C registers, and the value in the offset DAC. The transfer functions for the AD5360/AD5361 are shown in the following sections. AD5360 Transfer Function The input code is the value in the X1A or X1B register that is applied to DAC (X1A, X1B default code = 32,768) DAC_CODE = INPUT_CODE × (M + 1)/216 + C − 215 DAC output voltage VOUT = 4 × VREF × (DAC_CODE − (OFFSET_CODE × 4))/ 216 + VSIGGND where: DAC_CODE should be within the range of 0 to 65,535. VREF = 3.0 V, for a 12 V span. VREF = 5.0 V, for a 20 V span. M = code in gain register − default code = 216 – 1. C = code in offset register − default code = 215. OFFSET_CODE is the code loaded to the offset DAC. It is multiplied by 4 in the transfer function because this DAC is a 14-bit device. On power-up, the default code loaded to the offset DAC is 8192 (0x2000). With a 10 V reference, this gives a span of −10 V to +10 V. AD5361 Transfer Function The input code is the value in the X1A or X1B register that is applied to DAC (X1A, X1B default code = 8192) DAC_CODE = INPUT_CODE × (M + 1)/214 + C − 213 DAC output voltage VOUT = 4 × VREF × (DAC_CODE − OFFSET_CODE)/214 + VSIGGND where: DAC_CODE should be within the range of 0 to 16,383. VREF = 3.0 V, for a 12 V span. VREF = 5.0 V, for a 20 V span. M = code in gain register − default code = 214 − 1. C = code in offset register − default code = 213. OFFSET_CODE is the code loaded to the offset DAC. On power-up, the default code loaded to the offset DAC is 8192 (0x2000). With a 5 V reference, this gives a span of −10 V to +10 V. REFERENCE SELECTION The AD5360/AD5361 have two reference input pins. The voltage applied to the reference pins determines the output voltage span on VOUT0 to VOUT15. VREF0 determines the voltage span for VOUT0 to VOUT7 (Group 0), and VREF1 determines the voltage span for VOUT8 to VOUT15 (Group 1). The reference voltage applied to each VREF pin can be different, if required, allowing each group of eight channels to have a different voltage span. The output voltage range and span can be adjusted by programming the offset register and gain register for each channel as well as programming the offset DAC. If the offset and gain features are not used (that is, the M and C registers are left at their default values), the required reference levels can be calculated as follows: VREF = (VOUTMAX − VOUTMIN)/4 If the offset and gain features of the AD5360/AD5361 are used, the required output range is slightly different. The chosen output range should take into account the system offset and gain errors that need to be trimmed out. Therefore, the chosen output range should be larger than the actual, required range. The required reference levels can be calculated as follows: 1. Identify the nominal output range on VOUT. 2. Identify the maximum offset span and the maximum gain required on the full output signal range. 3. Calculate the new maximum output range on VOUT, including the expected maximum offset and gain errors. |
Similar Part No. - AD5360_15 |
|
Similar Description - AD5360_15 |
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
