ISL45042IRZ Intersil, ISL45042IRZ Datasheet - Page 6

• Manufacturer Part Number: ISL45042IRZ
• Description: IC CALIBRATOR LCD MODULE 8-DFN
• Manufacturer: Intersil
• Type: Calibratorr

Specifications of ISL45042IRZ

• Applications: LCD Display
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Expected Output Voltage
The ISL45042 provides an output sink current, which lowers
the voltage on the external voltage divider (V
voltage). Equations 1 and 2 can be used to calculate the
output current (I
(Where “Setting” is an integer between 1 and 128.)
Table 1 gives the calculated value of V
values of: R
AV
I
V
OUT
OUT
DD
FIGURE 3. EXTERNAL ESD PROTECTION ON CTL PIN
TABLE 1. CALCULATED VCOM OUTPUT VOLTAGES
SETTING VALUE
=
= 10V.
=
FIGURE 4. EXAMPLE OF THE REPLACEMENT FOR THE MECHANICAL POTENTIOMETER CIRCUIT USING THE ISL45042
Setting
-------------------- - x
⎛
⎜
⎝
R
R
R
-------------------- -
R
128
AVDD
a
b
c
1
10
20
30
40
50
60
70
80
R
SET
1
+
2
R
OUT
2
= 24.9kΩ, R
-------------------------- -
20 R
⎞
⎟
⎠
0.01µF
AV
AV
(
1kΩ
) and output voltage (V
DD
DD
SET
⎛
⎜
⎝
-
+
1
)
–
Setting
-------------------- - x
1
CTL
128
6
= 200kΩ, R
ISL45042
VCOM
-------------------------- -
20 R
OUT
R
R
R
(
R
2
SET
1
V
5.468
5.313
5.141
4.969
4.797
4.625
4.453
4.281
4.109
SET
1
= R
= R
2
OUT
OUT
for resistors
= 243kΩ, and
= (R
b
a
COM
)
⎞
⎟
⎠
+ R
a
) values.
(R
c
b
output
+ Rc)) / 20R
(EQ. 1)
(EQ. 2)
ISL45042
b
R
The external R
determines the lowest voltage of the external voltage divider R
and R
V
1.75V. This will keep the output MOS transistor in the saturation
region. Expected current settings and 7-bit accuracy occurs
when the output MOS transistor is operating in the saturation
region. Figure 5 shows the internal connection for the output
MOS transistor. The value of the AV
at the source of the output transistor. This voltage is equal to
(Setting/128) x (AV
to (Setting/128) x (AV
voltage is found using Equation 2. The values of R
Equation 2, should be determined (setting equal to 128) so the
minimum value of V
OUT
SET
AVDD
FIGURE 5. OUTPUT CONNECTION CIRCUIT EXAMPLE
TABLE 1. CALCULATED VCOM OUTPUT VOLTAGES
SETTING VALUE
2
pin and I
Resistor
(see Figure 1). The voltage difference between the
AVDD
100
110
128
SET
SETTING
----------------------------x
90
ISL45042
SET
SET
128
R
SET
DD
resistor sets the full-scale sink current that
pin (see Figure 5) has to be greater than
OUT
OUT
DD
/20). The I
AV
----------------- -
20
/20 x R
is greater than 1.75V + AV
DD
AVDD
SET
SET
R
R
1
2
). The value of the Drain
DD
VOUT PIN
current is therefore equal
supply sets the voltage
RSET
VSAT
0.5V
V
3.936
3.764
3.592
3.282
-
+
OUT
AV
1
DD
DD
ISET PIN
and R
R2
R1
= 15V
April 13, 2011
VCOM
/20.
FN6072.9
2
in
1