pca8576d NXP Semiconductors, pca8576d Datasheet - Page 7

• Manufacturer Part Number: pca8576d
• Description: Automotive 40 X 4 Lcd Segment Driver For Low Multiplex Rates Up To 1 4
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA8576D
Product data sheet
7.3.1 Electro-optical performance
where the values for n are
The RMS off-state voltage (V
Discrimination is the ratio of V
Using
1
1
The advantage of these LCD drive modes is a reduction of the LCD full scale voltage V
as follows:
These compare with
It should be noted that V
Suitable values for V
RMS voltage, at which a pixel will be switched on or off, determine the transmissibility of
the pixel.
For any given liquid, there are two threshold values defined. One point is at 10 % relative
transmission (at V
For a good contrast performance, the following rules should be followed:
V
of a, n (see
V
D
V
V


2
2
on(RMS)
•
•
off RMS
on RMS
off RMS
n = 1 for static mode
n = 2 for 1:2 multiplex
n = 3 for 1:3 multiplex
n = 4 for 1:4 multiplex
bias is
bias is
=



1:3 multiplex (
1:4 multiplex (
---------------------- -
V
V
Equation
off RMS
on RMS



and V




=
----------
V
V
3
3
21
Equation 1
V
high
low
LCD


=
off(RMS)
=
=
All information provided in this document is subject to legal disclaimers.
3, the discrimination for an LCD drive mode of 1:3 multiplex with
1.732
----------------------------- -
n
1.528
a
1
1
low

2



------------------------------------------- -

2
2
a
a 1
–
) and the other at 90 % relative transmission (at V
on(RMS)

bias):
bias):
V
1
+
are properties of the display driver and are affected by the selection
2a
–
LCD
and the discrimination for an LCD drive mode of 1:4 multiplex with
Automotive 40 x 4 LCD segment driver for low multiplex rates
to
+
.
1
Rev. 1 — 4 April 2011
LCD
+


a
Equation
2
2

n
V
V
=
2
+
+
and V
is sometimes referred as the LCD operating voltage.
LCD
LCD
off(RMS)


on(RMS)
3V
n 1
n 1
–
–
off RMS
=
=
off(RMS)



3) and the V
) for the LCD is calculated with
to V

--------------------- -
6
4



3
off(RMS)
V
are dependent on the LCD liquid used. The
when
off RMS
3


1
=
LCD

and is determined from
3

2.309V
bias is used.
=
voltage.
2.449V
off RMS

off RMS


PCA8576D
Equation

high
© NXP B.V. 2011. All rights reserved.
Equation
), see
2:
Figure
3:
7 of 42
LCD
(2)
(3)
(4)
(5)
4.