pcf8534a NXP Semiconductors, pcf8534a Datasheet - Page 7

• Manufacturer Part Number: pcf8534a
• Description: Universal Lcd Driver For Low Multiplex Rates
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF8534A_3
Product data sheet
Table 5
together with the biasing characteristics as functions of V
discrimination ratios (D).
A practical value for V
threshold voltage (V
the static drive mode a suitable choice is V
Multiplex drive ratios of 1:3 and 1:4 with
hence the contrast ratios are smaller e.g.:
The advantage of these modes is the reduction of the LCD full-scale voltage V
follows:
These compare with V
V
Table 5.
LCD drive
mode
static
1:2
1:2
1:3
1:4
•
•
oper
3
=
1:3 multiplex (
1:4 multiplex (
= V
1.732
shows the biasing configurations applicable to the preferred operating modes
LCD
Preferred LCD drive modes: summary of characteristics
Number of
Backplanes
1
2
2
3
4
.
for 1:3 multiplex or
1
1
2
2
th
bias):
bias):
Rev. 03 — 10 November 2008
), typically when the LCD exhibits approximately 10 % contrast. In
oper
oper
Levels
2
3
4
4
4
is determined by equating V
= 3V
V
V
oper
oper
off(RMS)
--------- -
=
=
3
21
LCD bias
configuration
static
1
1
1
1
2
3
3
3
-------------------- -
=
6 V
4
when
1.528
1
3
2
Universal LCD driver for low multiplex rates
oper
off RMS
bias are possible but the discrimination and
3
1
3
> 3V
for 1:4 multiplex
=
bias is used. It should be noted that
2.309V
0
0.354
0.333
0.333
0.333
V
----------------------- -
=
th
off RMS
V
.
2.449V
oper
off(RMS)
off RMS
oper
off RMS
and the resulting
with a defined LCD
1
0.791
0.745
0.638
0.577
V
---------------------- -
on RMS
V
oper
PCF8534A
© NXP B.V. 2008. All rights reserved.
2.234
2.237
1.915
1.732
D
=
oper
----------------------- -
V
V
off RMS
on RMS
as
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