FEDL9476-01
Issue Date: Oct. 1, 2010
ML9476
1/3 or 1/4 Duty, 16-Output LCD Driver
GENERAL DESCRIPTION
The ML9476 is an LCD driver for dynamic display. It has a function to switch between 1/3 and 1/4 duty. When
1/4 duty is selected, an LCD of up to 64 segments can be driven directly; when 1/3 duty is selected, an LCD of
up to 48 segments can be driven directly.
FEATURES
Logic power supply voltage
: 2.7 to 3.6 V, 4.5 to 5.5 V
Driver power supply voltage
: 3.5 to 5.5 V
Operating temperature
:
40
to +105°C
16 segment outputs
1/4 duty
: Up to 64 segments can be displayed.
1/3 duty
: Up to 48 segments can be displayed.
Serially interfaces with the CPU using the three signal lines of LOAD, DATA_IN, and CLOCK
Built-in RC oscillator circuit for LCD AC drive (the CLKSEL pin allows selecting an external clock input)
Built-in voltage-dividing resistor for bias voltage generation
Package
: 48-pin plastic TQFP (TQFP48-P-0707-0.50-K)
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FEDL9476-01
ML9476
BLOCK DIAGRAM
SEG1
SEG16
DVDD
16-Dot Segment Driver
Bias
Res..
16-Ch Data Selector
TEST
16
16
16
16
16-Bit
Latch4
16-Bit
Latch3
16-Bit
Latch2
16-Bit
Latch1
LOAD
LATCH
SELECTOR
16
DATA_IN
CLOCK
22(16 + 6)-bit Shift Register
OSC
OSC
TIMING
GENERATOR
COM1
CLKSEL
3/4SEL
COMMON
Driver
COM2
COM3
COM4
RESET
LVDD
VSS
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FEDL9476-01
ML9476
PIN CONFIGURATION (TOP VIEW)
DATA_IN
38
CLKSEL
48
47
46
45
44
43
42
41
40
39
COM2
COM1
SEG1
SEG2
SEG3
SEG4
SEG5
SEG6
SEG7
SEG8
SEG9
SEG10
37
CLOCK
3/4SEL
RESET
COM3
COM4
LVDD
TEST
OSC
VSS
N.C
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
LOAD
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
13
14
15
16
17
18
19
20
21
22
23
N.C
N.C
N.C
SEG11
SEG12
SEG13
SEG14
SEG15
48-Pin Plastic TQFP
N.C : No-Connection pin
SEG16
DVDD
N.C
N.C
24
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FEDL9476-01
ML9476
PIN DESCRIPTION
Symbol
I/O
Description
Pin for oscillation. Has a Schmitt circuit built in.
An oscillator circuit can be configured by connecting one external resistor and one
external capacitor.
Since an oscillator circuit is susceptible to external noise, make the wiring
between this pin and external components as short as possible. An external clock
input can be selected by CLKSEL.
The relationship between oscillation frequency f
OSC
and frame frequency f
FRM
is:
(*1)
f
FRM
= f
OSC
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Serial data input pin. Has a Schmitt circuit built in.
The LCD display is turned on when the input data signal is at a “H” level and
turned off when the input data signal is at a “L” level.
Shift clock input pin. Has a Schmitt circuit built in.
Data to the DATA_IN pin is shifted in sync with the rising edges of the shift clock
pulses.
Load pulse input pin. Has a Schmitt circuit built in.
Used to transfer serially input data to the display latch or write commands.
IC test pin. Has a pull-down resistor built in.
Leave this pin open or connect it to VSS when not used.
OSC pin input switching pin.
When using the built-in oscillator circuit, set this pin to a “L” level; when inputting
an external clock, set this pin to a “H” level. While this pin is at a “H” level, the
oscillator circuit connected is disabled.
1/3- or 1/4-duty switching input pin. When “H” level is input, 1/3 duty is selected
and when “L” level is input, 1/4 duty is selected.
Reset signal input pin for initializing the IC. Has a Schmitt circuit built in.
This pin is enabled by setting it to “L” level. This pin has a built-in pull-up resistor.
Normally, this pin, when connected with an external capacitor, performs power-on
(*2)
reset.
Output pins for LCD display. Connect to the common pins of the LCD panel.
- When 1/3 duty is selected:
Common signals are outputted through the COM1, COM2, and COM3 pins.
Leave the COM4 pin open.
- When 1/4 duty is selected:
Common signals are outputted through the COM1, COM2, COM3, and COM4
pins.
Output pins for LCD display. Connect to the segment pins of the LCD panel.
For the relationship between each output of these pins and data, see the section
on “Data Structure.”
Logic power supply pin.
LCD driver power supply pin.
Ground pin.
No-Connection pin. Normally leave this pin open.
OSC
I/O
DATA_IN
I
CLOCK
LOAD
TEST
I
I
I
CLKSEL
I
3/4SEL
I
RESET
I
COM1
COM2
COM3
COM4
O
SEG1 to SEG16
LVDD
DVDD
VSS
N.C
O
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FEDL9476-01
ML9476
*1: Oscillator circuit configuration
LVDD
R
O
OSC
C
O
*2: Reset circuit configuration
LVDD
C
RST
RESET
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