PCF8576CT NXP Semiconductors, PCF8576CT Datasheet - Page 10

• Manufacturer Part Number: PCF8576CT
• Manufacturer: NXP Semiconductors

Specifications of PCF8576CT

• Operating Supply Voltage (typ): 2.5/3.3/5V
• Number Of Digits: 20
• Number Of Segments: 160
• Package Type: VSO
• Pin Count: 56
• Mounting: Surface Mount
• Power Dissipation: 400mW
• Frequency (max): 315KHz
• Operating Supply Voltage (min): 2V
• Operating Supply Voltage (max): 6V
• Lead Free Status / Rohs Status: Compliant

NXP Semiconductors
PCF8576C_9
Product data sheet
7.2 LCD bias generator
7.3 LCD voltage selector
Remark: Do not transfer data on the I
reset action to complete.
The full-scale LCD voltage (V
temperature compensated externally through the V
Fractional LCD biasing voltages are obtained from an internal voltage divider comprising
three series resistors connected between V
switched out of the circuit to provide a
configuration.
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
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 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
a = 1 for
a = 2 for
The I
The data pointer and the subaddress counter are cleared
and the resulting discrimination ratios (D), are given in
LCD
2
=
C-bus interface is initialized
Preferred LCD drive modes: summary of characteristics
1
1
2
3
V
is the resultant voltage at the LCD segment and where the values for n are
Number of:
Backplanes Bias levels
1
bias
bias
LCD
1
-- -
n
+
th
------------ -
1
---------------- -
), typically when the LCD exhibits approximately 10 % contrast. In
LCD
n 1
1
+
–
n
Rev. 09 — 9 July 2009
a
is determined by equating V
2
3
4
4
4
, where the values for a are
on(RMS)
oper
------------ -
1
) is obtained from V
+
1
a
) for the LCD is calculated with
2
2
C-bus for at least 1 ms after a power-on to allow the
1
LCD bias
configuration
static
1
1
1
1
2
3
3
3
2
bias voltage level for the 1:2 multiplex
1
Universal LCD driver for low multiplex rates
LCD
2
DD
bias are possible but the discrimination and
and V
3
LCD
DD
LCD
V
V
--------------------------
0
0.354
0.333
0.333
0.333
th
off(RMS)
off RMS
V
supply to pin V
.
. The center resistor can be
LCD
V
LCD
Table
with a defined LCD
. The LCD voltage may be
1
0.791
0.745
0.638
0.577
V
------------------------ - D
on RMS
V
5.
PCF8576C
Equation 1
LCD
LCD
© NXP B.V. 2009. All rights reserved.
.
2.236
2.236
1.915
1.732
=
--------------------------
V
V
off RMS
on RMS
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