PCF8576DT/S400/2,1 NXP Semiconductors, PCF8576DT/S400/2,1 Datasheet - Page 9

• Manufacturer Part Number: PCF8576DT/S400/2,1
• Description: LCD Drivers 2.64KHz 50mA 400mW
• Manufacturer: NXP Semiconductors

Specifications of PCF8576DT/S400/2,1

• Rohs: yes
• Maximum Clock Frequency: 2.64 kHz
• Operating Supply Voltage: 1.8 V to 5.5 V
• Package / Case: TSSOP-56
• Maximum Power Dissipation: 400 mW
• Maximum Supply Current: 50 mA
• Mounting Style: SMD/SMT
• Factory Pack Quantity: 2000

NXP Semiconductors
PCF8576D
Product data sheet
7.3 LCD voltage selector
The LCD voltage selector coordinates the multiplexing of the LCD in accordance with the
selected LCD drive configuration. The operation of the voltage selector is controlled by the
mode-set command from the command decoder. The biasing configurations that apply to
the preferred modes of operation, together with the biasing characteristics as functions of
V
Discrimination is a term which is defined as the ratio of the on and off RMS voltage across
a segment. It can be thought of as a measurement of contrast.
Table 5.
A practical value for V
threshold voltage (V
the static drive mode a suitable choice is V
Multiplex drive modes of 1:3 and 1:4 with
hence the contrast ratios are smaller.
Bias is calculated by
The RMS on-state voltage (V
where the values for n are
The RMS off-state voltage (V
Discrimination is the ratio of V
V
V
LCD drive
mode
static
1:2 multiplex 2
1:2 multiplex 2
1:3 multiplex 3
1:4 multiplex 4
LCD
on RMS
off RMS
a = 1 for
a = 2 for
n = 1 for static drive mode
n = 2 for 1:2 multiplex drive mode
n = 3 for 1:3 multiplex drive mode
n = 4 for 1:4 multiplex drive mode
(
(
and the resulting discrimination ratios (D) are given in
)
)
=
=
Biasing characteristics
1
1
⁄
⁄
V
2
3
V
LCD
LCD
Number of:
Backplanes Levels
1
bias
bias
All information provided in this document is subject to legal disclaimers.
----------------------------- -
n
----------------------------- -
n
a
a
2
×
2
×
th(off)
+
–
(
(
------------ -
1
1
1
LCD
2a
2a
1
+
+
+
Rev. 13 — 10 May 2012
), typically when the LCD exhibits approximately 10 % contrast. In
a
+
+
a
a
is determined by equating V
)
, where the values for a are
n
)
n
2
3
4
4
4
2
2
on(RMS)
off(RMS)
on(RMS)
LCD bias
configuration
static
1
1
1
1
) for the LCD is calculated with
⁄
⁄
⁄
⁄
) for the LCD is calculated with
2
3
3
3
to V
off(RMS)
1
Universal LCD driver for low multiplex rates
⁄
LCD
2
bias are possible but the discrimination and
> 3V
and is determined from
th(off)
0
0.354
0.333
0.333
0.333
V
------------------------ -
off RMS
V
off(RMS)
LCD
(
.
Table
)
with a defined LCD
1
0.791
0.745
0.638
0.577
V
----------------------- -
on RMS
V
5.
(
LCD
PCF8576D
Equation
Equation
)
© NXP B.V. 2012. All rights reserved.
Equation
∞
2.236
2.236
1.915
1.732
D
=
1:
2:
------------------------ -
V
V
on RMS
off RMS
3:
(
(
9 of 56
(1)
(2)
)
)