Electronic Components Datasheet Search |
|
ISL24201IRTZ-EVALZ Datasheet(PDF) 6 Page - Intersil Corporation |
|
ISL24201IRTZ-EVALZ Datasheet(HTML) 6 Page - Intersil Corporation |
6 / 12 page ISL24201 6 FN7586.1 December 9, 2010 DCP (Digitally Controlled Potentiometer) Figure 4 shows the relationship between the register value and the resistor string of the DCP. Note that the register value of zero actually selects the first step of the resistor string. The output voltage of the DCP is given by Equation 1: Output Current Sink Figure 5 shows the schematic of the OUT pin current sink. The circuit made up of amplifier A1, transistor Q1, and resistor RSET forms a voltage controlled current source. The external RSET resistor sets the full-scale sink current that determines the lowest output voltage of the external voltage divider R1 and R2. IOUT is calculated as shown by Equation 2: The maximum value of IOUT can be calculated by substituting the maximum register value of 255 into Equation 2, resulting in Equation 3: Equation 2 can also be used to calculate the unit sink current step size by removing the Register Value term from it as shown in Equation 4. The voltage difference between the OUT pin and SET pin, which are also the drain and source of the output transistor, should be greater than the minimum saturation voltage for the IOUT(MAX) being used. This will keep the output transistor in its saturation region to maintain linear operation over the full range of register values. Figure 6 shows IDS vs VDS for transistor Q1. The line labeled "Minimum Saturation Voltage" is the minimum voltage that should be maintained across the drain and source of Q1. To find the minimum saturation voltage for a specific condition, locate the voltage at the intersection of the IOUT(MAX) value from Equation 3 and the line labeled "Minimum Saturation Voltage". VDCP RegisterValue 1 + 256 --------------------------------------------------- ⎝⎠ ⎛⎞ AVDD 20 -------------- ⎝⎠ ⎛⎞ = (EQ. 1) AVDD 19R R 0 1 2 255 254 253 252 251 REGISTER VALUE AVDD 20 VDCP FIGURE 4. SIMPLIFIED SCHEMATIC OF DIGITAL CONTROL POTENTIOMETER (DCP) AVDD RSET VDCP SET OUT AVDD IOUT R1 R2 VSAT VSET = (IOUT)*(RSET) = VDCP Q1 A1 VOUT FIGURE 5. CURRENT SINK CIRCUIT IOUT VDCP RSET ------------- RegisterValue 1 + 256 --------------------------------------------------- ⎝⎠ ⎛⎞ AVDD 20 -------------- ⎝⎠ ⎛⎞ 1 RSET ------------- ⎝⎠ ⎛⎞ == (EQ. 2) IOUT MAX () AVDD 20RSET -------------------- = (EQ. 3) ISTEP AVDD 256 () 20 () RSET () ---------------------------------------------- = (EQ. 4) FIGURE 6. IDS vs VDS FOR THE ISL24201 OUTPUT TRANSISTOR 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 012 34 5 6 7 8 9 10 VDS (V) SATURATION REGION MINIMUM SATURATION VOLTAGE |
Similar Part No. - ISL24201IRTZ-EVALZ |
|
Similar Description - ISL24201IRTZ-EVALZ |
|
|
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 |