SANYO LC74751 Datasheet

Overview

The LC74751 is a CMOS LSI that supports on-screen
display of characters and patterns on a TV screen under
the control of a microcontroller. The LC74751 includes an
on-chip character ROM that provides 128 characters in a
12 × 18 dot format. This IC supports display of up to 12
lines of 24 characters each for a maximum of 288
characters.

Features

• Display format: 24 characters by 12 rows

• Characters displayed: Up to 288 characters

• Display control ROM (line ROM): ROM for 64 lines
(Control in line units: lines consisting of 24 characters)

• Display RAM: 176 characters (Used for the specification
of user-defined characters.)

• Character format: 12 (horizontal) × 18 (vertical) dots

• Characters in font: 128

• Character sizes: Four sizes each in the horizontal and
vertical directions

• Initial display positions: 64 horizontal positions and 64
vertical positions

• Blinking: Specifiable in character units

• Blinking types:
— Two periods supported: 1.0 second and 0.5 second
— Three duty types supported: 25%, 50%, and 75%

• Blanking: Over the whole font (12 × 18 dots)

• Background color
— 8 background colors (in internal synchronization

mode): 4fsc (NTSC/PAL/PAL-M/PAL-N)

— 4 background colors (in internal synchronization

mode): 2fsc (NTSC)

— Single background color (blue) (in internal

synchronization mode): 2fsc (PAL/PAL-M/PAL-N)

• External control input: Serial data input

• Synchronizing signals: Supports switching between
internal and external synchronizing signals.

• On-chip sync separator circuit

• Video output: Composite video output in the NTSC,
PAL, PAL-M, or PAL-N format

• Superimpose function: Superimposes the character
output on the composite video output.

Package Dimensions

unit: mm

3059-DIP22S

CMOS LSI

Ordering number : EN*5396

83096HA (OT) No. 5396-1/15

Preliminary

SANYO: DIP22S

[LC74751]

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

On-Screen Display LSI

LC74751

Pin Assignment

No. 5396-2/15

LC74751

Parameter Symbol Conditions

Ratings

Unit

min typ max

Supply voltage

V

DD1VDD1

4.5 5.0 5.5 V

V

DD2VDD2

4.5 5.0 1.27 V

DD1

V

Input high-level voltage V

IH

CS, SIN, RST, SCLK, and SEP

IN

0.8 V

DD1

V

DD1

+ 0.3 V

Input low-level voltage V

IL

CS, SIN, RST, SCLK, and SEP

IN

V

SS

– 0.3 0.2 V

DD1

V

Composite video input voltage

V

IN1

CV

IN

2 Vp-p V

V

IN2

SYN

IN

2 Vp-p 2.5 Vp-p V

f

OSC1

Crystal oscillator pins (NTSC: 2fsc mode) 7.15909 MHz

f

OSC2

Crystal oscillator pins (NTSC: 4fsc mode) 14.31818 MHz

Oscillator frequency

f

OSC3

Crystal oscillator pins (PAL: 4fsc mode) 17.73447 MHz

f

OSC4

Crystal oscillator pins (PAL-M: 4fsc mode) 14.30244 MHz

f

OSC5

Crystal oscillator pins (PAL-N: 4fsc mode) 14.32822 MHz

f

OSC6

LC oscillator pin (When an LC oscillator is used)

5 7 11 MHz

Allowable Operating Ranges

Specifications

Absolute Maximum Ratings

Parameter Symbol Conditions Ratings Unit

Supply voltage V

DD

V

DD1

and V

DD2

VSS–0.3 to VSS+7.0 V

Input voltage V

IN

All input pins VSS–0.3 to VDD+0.3 V

Output voltage V

OUT

VSS–0.3 to VDD+0.3 V
Allowable power dissipation Pd max Ta = 25°C 300 mW
Operating temperature Topr –30 to +70 °C
Storage temperature Tstg –40 to +125 °C

Parameter Symbol Conditions

Ratings

Unit

min typ max

Output off leakage current I

leak

CV

OUT

10 µA

Output high-level voltage V

OH1

SEP

OUT

: V

DD1

= 4.5 V, IOH= –1.0 mA 3.5 V

Output low-level voltage V

OL1

SEP

OUT

: V

DD1

= 4.5 V, IOL= 1.0 mA 1.0 V

Input current

I

IH

CS, SIN, RST, SCLK, and SEPIN: VIN= V

DD1

1 µA

I

IL

OSCIN: VIN= V

SS

–1 µA

Operating current drain

I

DD1VDD1

; All outputs open, Xtal: 17.734MHz, LC = 7MHz

10 mA

I

DD2VDD2

; V

DD2

= 5.0 V 15 mA

Electrical Characteristics at Ta = –30 to +70°C, V

DD1

= 5 V unless otherwise specified

No. 5396-3/15

LC74751

Parameter Symbol Conditions

Ratings

Unit

min typ max

Minimum input pulse width

t

W(SCLK)

SCLK 200 ns

t

W(CS)

CS (the period when CS is high) 1 µs

Data setup time

t

SU(CS)

CS 200 ns

t

SU(SIN)

SIN 200 ns

Data hold time

t

h(CS)

CS 2 µs

t

h(SIN)

SIN 200 ns

One-word write time

t

word

The time to write 16 bits of data 10 µs

t

wt

The time to write data to RAM 1 µs

Timing Characteristics at Ta = –30 to +70°C, V

DD1

= 5±0.5 V

Serial Data Input Timing

Pin Functions

No. 5396-4/15

LC74751

Pin no. Pin Function Notes

1 V

SS

Ground Ground (digital system ground)

2 Xtal

IN

Crystal oscillator

Connections for the crystal and capacitors used to form the crystal oscillator for generating

3 Xtal

OUT

internal synchronizing signals.

4 TEST Test output Test data output
5 RST Reset input System reset input (This input has hysteresis characteristics.)
6 SCLK Clock input

Clock input for the serial data input function (This input has hysteresis characteristics.)

7 SIN Data input

Serial data input (This input has hysteresis characteristics.)
Data is input in 16-bit units.

8 CS Enable input

Serial data input enable input (This input has hysteresis characteristics.)
Serial data input is enabled when this pin is low.

9 LVBK Blanking level adjustment input Level input signal used to adjust the blanking level.
10 LVCHA Character level adjustment input Level input signal used to adjust the character level.
11 V

DD2

Power supply Composite video signal adjustment power supply (analog system power supply)

12 CV

OUT

Video signal output Composite video signal output
13 NC This pin must be either connected to ground or left open.
14 CV

IN

Video signal input Composite video signal input

15 V

DD1

Power supply Power supply (+5 V)

16 SYN

IN

Sync separator circuit input Input to the composite sync signal sync separator circuit

17 SEP

C

Sync separator circuit adjustment Sync separator circuit adjustment

18 SEP

OUT

Composite sync signal output Sync separator circuit composite sync signal output

19 SEP

IN

Vertical synchronizing signal input

Connect an integration circuit between the SEP

OUT

pin and this pin, which inputs the vertical

synchronizing signal, to integrate the output signal from the SEP

OUT

pin.

20 OSC

OUT

LC oscillator

Connections for the coil and capacitor that form the oscillator used to generate the character

21 OSC

IN

output dot clock.

22 V

DD1

Power supply (+5 V) Power supply (+5 V)

System Block Diagram

Display Screen Structure

The display mode has a 24-character by 12-row format.
The maximum number of characters that can be displayed is 288.
When character sizes are enlarged, the maximum number of characters that can be displayed is reduced.
Display ROM (12-line specification) and display RAM (for 176 characters)

• Specify fixed characters in the display line ROM.

• Application programs use the display RAM to specify characters for sections of the display in which the characters
change.

No. 5396-5/15

LC74751