LC7461.PDF

Ordering number: EN2119D

CMOS LSI

LC7461M

Infrared Remote Control Transmitter IC

Functions

. 32%3 function keys

Package Dimensions

unit : mm

. Operating supply voltage range V DD = 1.8 to 3.6 V

3045B-MFP24

. Supply current at the standby mode I DD = 1 µA or less

. Double-press operation keys (no priority given)

[LC7461M]

. On-chip oscillator (ceramic resonator : connected externally)

Features

. The custom code consists of 7 bits to be fixed by the

on-chip ROM and 6 bits being pin-settable. Sixty-four

custom codes may be selected externally (no diode required).

SANYO : MFP24

Specifications

Absolute Maximum Ratings at Ta = 25°C

Parameter

Symbol

Conditions

Ratings

Unit

Maximum supply voltage

V DD max V DD

V SS –0.3 to +5.5

Input voltage

V IN Each input pin

V SS –0.3 to V DD +0.3

Output voltage

V OUT Each output pin

V SS –0.3 to V DD +0.3

Output current

I OUT OUT

–35

Allowable power dissipation

Pd max Ta % 85°C

150

Operating temperature

Topr

–40 to +85

°C

Storage temperature

Tstg

–50 to +125

°C

Allowable Operating Conditions at Ta = 25°C

Parameter

Symbol

Pin Name

Conditions

min typ max Unit

Supply voltage

V DD

V DD f OSC = 455 kHz

1.8 3.0

3.6 V

K I 0toK I 3,

C 0 to C 5

Input high-level voltage

V IH

0.7 V DD

V DD V

Input low-level voltage

V IL

K I 0toK I 3,

C 0 to C 5

V SS

0.3V DD V

Oscillation frequency

f OSC

400 455 500 kHz

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

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

O3096HA(II)/7058YT/6036KI,TS(KOTO) No.2119-1/7

. 13-bit custom codes

. Minimum number of external parts required

LC7461M

Electrical Characteristics at Ta = 25°C, V DD = 3.0 V

Parameter

Symbol

Pin Name

Conditions

min typ max Unit

Operating supply

current

I DD

V DD Key ON, output: no load

1 mA

Quiescent supply

current

I DS

V DD All keys OFF, OSC stop

1 µA

Output high-level

current

I OH 1

OUT V DD = 1.8 V, V OH = 1.0 V

–8

I OH 2

OUT V DD = 3.0 V, V OH = 1.0 V

–25

Output high-level

voltage

V OH

K O 0toK O 7I OH = –0.1 mA

0.3 V

Output low-level

voltage

V OL

OUT I OL = 0.1 mA

0.3 V

Output OFF-state

leakage current

I OFF

K O 0toK O 7

1 µA

Input high-level current

I IH

C 0 to C 5 V IN =V DD

Input low-level current

I IL

C 0 to C 5 V IN =V SS

–1

µA

Input floating voltage

V IF

K I 0toK I 3

0.1 V DD V

Input pull down

resistance

R IN

K I 0toK I 3

75 100

125 k

Internal Block Diagram

Key

output

timing

signal

generator

Output

circuit

Oscillator

Divider

Decoder

Key

entry

circuit

Key data

Custom code

No.2119-2/7

LC7461M

Pin Assignment

Top view

Pin Description

Pin Name Pin No. Input/Output Internal Equivalent Circuit

Pin Function

V DD ,V SS

8, 12

Power supply pins V SS = GND

K O 0toK O 7 13 to 20

Output

Key scan timing signal output pins

K I 0toK I 3

1 to 4

Input

Keys return signal entry pins

Input/output pins for ceramic resonator-used

oscillation

OSC1

OSC2

Input/output

Oscillator configuration

C 0 to C 5

21 to 24,

5, 6

Input

Input pins for custom code setting

Capable of externally setting 6 bits of 13 bits in

all that provide a custom code

OUT

Output

Output pin for transmit LED drive

TEST

Input

LSI test pin

Normally set to high-level or brought to open

state

No.2119-3/7

LC7461M

General Description of Function

1. Oscillator

Since a self-bias type amplifier of CMOS inverter is contained, an oscillator can be formed by connecting a ceramic

resonator.

To minimize power dissipation, the oscillator stops oscillating except when key operation is performed.

2. Key entry

Key entry pins K I 0toK I 3 and timing signal output pins K O 0toK O 7 provide a key matrix of 4 ´ 8 = 32.

Multi-press of key No. 20 and one of key No. 21, 22, 23 may be done, with no priority given in key entry. When the two

keys are kept pressed, a series of pulses will be output according to each key entry. If multi-press of keys which are not

allowed multi-press is done, no output will be delivered.

3. Data organization

Data consists of 42 bits in all: 13 bits of custom code, 8 bits of key data, and their inverted codes.

Custom code

Key data

13 bits

8 bits

No.2119-4/7

LC7461M

(a) Custom code

The custom code, which consists of 13 bits (C 0 to C 12 ) in all, is used to distinguish between receiving sets.

Pin-selectable Mask ROM

6 bits

7 bits

C 6 to C 12 are fixed by the mask ROM and C 0 to C 5 are pin-settable.

In this example C 0 to C 5 are

set as follows:

C 0 C 1 C 2 C 3 C 4 C 5

011001

The custom codes are controlled by Sanyo to avoid duplication.

(b) Key data

KEY No. D 0 D 1 D 2 D 3 D 4 D 5 D 6 D 7

0 0 0 0 0 0 0 0 0

1 1 0 0 0 0 0 0 0

2 0 1 0 0 0 0 0 0

3 1 1 0 0 0 0 0 0

4 0 0 1 0 0 0 0 0

. . .

Multi-press

. . .

29 1 0 1 1 1 0 0 0

30 0 1 1 1 1 0 0 0

31 1 1 1 1 1 0 0 0

. . .

KEY No. D 0 D 1 D 2 D 3 D 4 D 5 D 6 D 7

20, 21 1 0 1 0 1 1 0 0

20, 22 0 1 1 0 1 1 0 0

20, 23 1 1 1 0 1 1 0 0

. 6 ,D 7 may be preset to ‘‘0’’,‘‘1’’ beforehand (mask

option).

When multi-press of key No.20 and one of key No.21, 22, 23 is done, multi-bit D 5 will be set to ‘‘1’’, with no priority given

in key entry.

(H: Key-ON state)

Key 20

data

transmit

Keys 20, 21

multi-press

data transmit

Key 21

data

transmit

Transmit

stop

Key 22

data

transmit

Keys 20, 22

multi-press data

transmit

No.2119-5/7

. . .

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