ISL24201IRTZ datasheet(7/12 Pages) INTERSIL

部件名	ISL24201IRTZ

功能描述	Programmable VCOM Calibrator with EEPROM Pb-free (RoHS-compliant)

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制造商	INTERSIL [Intersil Corporation]

网页	http://www.intersil.com/cda/home

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7 / 12 page

ISL24201

7

FN7586.1

December 9, 2010

The maximum voltage on the SET pin is AVDD/20 and is added to

the minimum voltage difference between the VOUT and SET pins to

calculate the minimum VOUT voltage, as shown in Equation 5.

Output Voltage

The output voltage, VOUT, of the OUT pin can be calculated from

Equation 6:

While Equation 6 can be used to calculate the output voltage, it

does not help select the values of R1, R2 and RSET to obtain a

specific range of VCOM voltages.

Output Voltage Span Calculation

The span of the output voltage is typically centered around the

nominal VCOM voltage value, which is typically near half of the

AVDD voltage. The high VCOM voltage occurs with the register

value of zero, while the low VCOM voltage occurs with the register

value of 255. Figure 7 shows the definition of several terms used

later in the text.

There are three variables that control the VCOM calibrator’s

operating point; the span of the VCOM voltage, the maximum

current sink and the source impedance of the resistive divider.

Figure 8 shows a range of operating points for these three variables

and a quick way to estimate a specific operating point. The X-axis is

the span of the VCOM voltage (High VCOM Voltage - Low VCOM

Voltage), and the Y-axis is the maximum sink current set by RSET.

The individual plots of each RTH show the VCOM span plotted against

the maximum OUT sink current given that value of source

impedance of the voltage divider. RTH is the Thevenin equivalent

resistance of the voltage divider R1 and R2, which is the resistance

of the parallel combination of R1 and R2, as shown in Equation 7.

The span of the VCOM voltage is shown by Equation 8.

To make a final selection of the resistor values for R1 and R2, The

supply voltage AVDD and the value of RSET are specified. The

calculations for R1 and R2 are shown in Equations 9 and 10:

The R1 and R2 calculations are based on the span of the VCOM

voltage being centered at half the AVDD voltage.

As an example, AVDD = 15V, the maximum value for ISET is

selected to be 100µA and the required span is 2V. Using Figure 8

as a guide, the VCOM maximum is equal to 8.5V and the VCOM

minimum is equal to 6.5V. Rearranging equation and calculation

the value of RSET:

Calculating the value of R1 is shown in Equation 12.

Calculating the value of R2 is shown in Equation 13.

VOUT MIN

()

AVDD

20

--------------

MinimumSaturationVoltage

+

≥

(EQ. 5)

VOUT

AVDD

R2

R1 R2

+

--------------------

⎝⎠

⎜⎟

⎛⎞

1

RegisterValue 1

+

256

---------------------------------------------------

R1

20RSET

--------------------

⎝⎠

⎜⎟

⎛⎞

–

⎝⎠

⎜⎟

⎛⎞

=

(EQ. 6)

GND

AVDD

NOM INAL VCOM VOLTAGE

HIGH VCOM VOLTAGE

LOW VCOM VOLTAGE

SPAN

FIGURE 7. VOLTAGE LEVELS FOR VCOM

RTH

R1R2

R1 R2

+

--------------------

=

(EQ. 7)

VCOMSPAN

ISET RTH

()

=

(EQ. 8)

FIGURE 8. GRAPH of VCOM SPAN vs MAXIMUM OUTCURRENT

AND RTH

0.6

0.5

0.4

0.3

0.2

0.1

0

01234

56

VCOM SPAN (V)

RTH

= 2

5kΩ

RTH =

50kΩ

RTH = 10

0kΩ

R1

40RSET SPAN

()

AVDD SPAN

+

------------------------------------------

=

(EQ. 9)

R2

40RSET SPAN

()

AVDD SPAN

–

------------------------------------------

=

(EQ. 10)

RSET

AVDD

20IOUT MAX

()

-------------------------------------

15

20 0.000100

()

--------------------------------------

7500

Ω

==

=

(EQ. 11)

R1

40 7500

() 2

()

15 2

+

-----------------------------------

39.29k

Ω

==

(EQ. 12)

R2

40 7500

() 2

()

15 2

–

-----------------------------------

46.15k

Ω

==

(EQ. 13)

类似零件编号 - ISL24201IRTZ

制造商	部件名	数据表	功能描述
Intersil Corporation	ISL24201IRTZ	465Kb / 12P	Programmable VCOM Calibrator with EEPROM December 9, 2010
Renesas Technology Corp	ISL24201IRTZ	609Kb / 12P	Programmable VCOM Calibrator with EEPROM
Intersil Corporation	ISL24201IRTZ-EVALZ	465Kb / 12P	Programmable VCOM Calibrator with EEPROM December 9, 2010
Renesas Technology Corp	ISL24201IRTZ-EVALZ	609Kb / 12P	Programmable VCOM Calibrator with EEPROM

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