Silan
Semiconductors
SC7461
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-02-28.
1
INFRARED REMOTE CONTROL
TRANSMITTER
DESCRIPTION
The SC7461 is a remote control transmitter utilizing CMOS
Technology specially designed for infrared applications. It is
capable of controlling 32 function keys and 3 double keys. SC7461 is
housed in 24 pins, SO Package and provides 13 bits Custom Code.
FEATURES
* CMOS Technology
* Low Power Consumption
* 32+3 Function Keys
* Least External Components
* Wide range of operating voltage: V
DD
=2.0~5.5V
* Double key operation(No order of priority given)
* On-Chip Oscillator can be constructed using an externally
connected ceramic resonator
* Up to 64 Custom Codes may be selected externally for SC7461
APPLICATIONS
* TV and VCR
* Audio Equipment
SOP-24
ORDERING INFORMATION
Part No.
Package
SC7461
SOP-24-375-1.27
* Audio Cassette Deck
* Air Conditioner
* Multi-Media DVD Player
ORDERING INFORMATION
Valid Part Number
Package
Custom Code in Mask ROM
SC7461-100
SOP-24
C6~C12=1000000
SC7461-101
SOP-24
C6~C12=0000000
SC7461-103
SOP-24
C6~C12=0010000
SC7461-104
SOP-24
C6~C12=1010000
Silan
Semiconductors
SC7461
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-02-28.
2
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
KI0
KI1
KI2
KI3
C4
C5
OUT
V
DD
TEST
OSCI
OSCO
V
ss
C3
C2
C1
C0
KO0
KO1
KO2
KO3
KO4
KO5
KO6
KO7
SC7461
BLOCK DIAGRAM
Key
Input
Scan
Circuit
OSC Circuit
Timing
Generation
&Control Circuit
Code Generation Circuit
Key Output Timing Signal Generator
Custom
Code
Register
KI0
KI1
KI2
KI3
KO0
KO1
KO2
KO3
KO4
KO5
KO6
KO7
C0
OUT
OSCI
OSCO
V
DD
V
SS
Output Circuit
C1
C2
C3
C4
C5
TEST
1
4
3
2
11
10
8
12
21
7
22
23
24
5
6
19
20
17
18
14
16
13
14
9
Silan
Semiconductors
SC7461
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-02-28.
3
ABSOLUTE MAXIMUM RATING
(Tamb=25
C,
unless otherwise specified)
Characteristic Symbol Description
Value Unit
Maximum Supply Voltage
V
DD(max)
V
DD
Vss-0.3~10
V
Input Voltage
V
IN
Each Input pin
Vss-0.3~V
DD
+0.3
V
Output Voltage
V
OUT
--
Vss-0.3~V
DD
+0.3
V
Output Current
I
OUT
OUT
-35
mA
Allowable Power Dissipation
Pd
(max)
Ta<=85
C
150
mW
Storage Temperature
T
stg
--
-40~+125
C
Operating Temperature
T
opr
--
-10~+70
C
ELECTRICAL CHARACTERISTICS
(Tamb=25
C
, V
DD
=3.0V,unless otherwise specified)
Parameter Symbol
Test
conditions
Min
Typ
Max
Unit
Operating Supply Current
I
DD
Key ON, Output: no load
1
mA
Quiescent Supply Current
I
DS
All keys OFF, OSC stops
1
A
I
OH1
V
DD
=1.8V, V
OH
=1.0V
-8
mA
High Level Output Current
I
OH2
V
DD
=3.0V, V
OH
=2.0V
-25
mA
High Level Output Voltage
V
OH
I
OH
=1mA
2.4
V
Low Level Output Voltage
V
OL
I
OL
=1mA
0.2
V
Output OFF-State Leakage Current
I
OFF
--
1
A
Custom Code High Level Input Current
I
IH
V
IN
= V
DD
1
A
Custom Code Low Level Input Current
I
IL
V
IN
= V
SS
-1
A
Input Floating Voltage
V
IF
--
0.1V
DD
V
Input Pull-Down Resistance
R
IN
--
75
100
125
k
RECOMMENDED OPERATING CONDITIONS
(Tamb=25
C, fosc=455kHz,unless otherwise specified)
Characteristic Symbol
Min.
Typ.
Max.
Unit
Supply Voltage
V
DD
2.0
3.0
3.3
V
High Level Input Voltage
V
IH
0.7V
DD
V
DD
V
Low Level Input Voltage
V
IL
Vss
0.3V
DD
V
Oscillation Frequency
fosc
400
455
500
KHz
Silan
Semiconductors
SC7461
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-02-28.
4
PIN DESCRIPTION
Pin No.
Symbol
I/O
Description
1~4
KI0~KI3
I
Key Input Pins
7
OUT
O
Output Pins For Transit LED Drive
8
V
DD
--
Power Supply
9
TEST
I
LSI Test Pin. This pin is normally set to High State or Floating.
10
OSCI
I
Oscillator Input Pin
11
OSCO
O
Oscillator Output Pin
12
V
SS
--
Power Supply Vss=GND
13~20
KO7~KO0
O
Key Scan Timing Signal Output Pins
21~24
5,6
C0~C3
C4~C5
I
Custom Code Input Pins. Capable of externally setting 6 out of
13 bits for custom coding.
FUNCTIONAL DESCRIPTION
1.OSCILLATION CIRCUIT
A self-biased type amplifier is housed by a CMOS Inverter Method. Thus, an oscillation circuit can be
constructed by connecting a ceramic resonator. Please refer to Figure 4 for the oscillation circuit diagram.
100pF
100pF
455KHz
V
DD
SC7461
FIGURE 1. OSCILLATION CIRCUIT DIAGRAM
Unless the keys are being operated, the oscillation is normally stopped. Thus, power consumption is considerably
reduced.
2.KEY INPUT
A total of 32 keys can be connected by Key Inputs--KI0~KI3 and Timing Signals--KO0~KO7. Double Key
Operation is possible for only Key No.20 in combination with the other keys connected to the KO5 line, namely: Key
No.21, 22 or 23. Thus, only the following key combinations may be used for the double key operation:
1).Key Nos.20 and 21
2).Key Nos.20 and 22
3).Key Nos.20 and 23
Silan
Semiconductors
SC7461
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 2.2
2002-02-28.
5
There is no order of priority given in key input. This means that keys designated for the double keying operation
may be pressed in any sequence. When two keys (designated for the double key operation) are pressed
simultaneously, a series of pulse is outputted according to each key input. Pressing other keys that are NOT
intended for the double key operation do NOT generate any output.
The Key Matrix is given in the following diagram.
5
1
13
9
21
17
29
25
6
2
14
10
22
18
30
26
7
3
15
11
23
19
31
27
8
4
16
12
24
20
0
28
KI0
KI1
KI2
KI3
KO0 KO1 KO2 KO3 KO4 KO5 KO6 KO7
FIGURE 2. KEY MATRIX
3.DOUBLE KEY OPERATION
Double Key Operation is useful for tape deck recording operation. The following table shows the Key Data
corresponding to the double keys pressed. Also refer to the Key Input Section.
Key D0 D1 D2 D3 D4 D5 D6 D7
K20+K21
1
0
1
0
1
1
0
0
K20+K22
0
1
1
0
1
1
0
0
K20+K23
1
1
1
0
1
1
0
0
NOTE: Key Data--D6 and D7 may be preset to "0", "1" by mask option.
Key 20
Key 21
Key 22
Key 20
Transmission
Data
Key 20&21
Transmission
Data
Key 21
Transmission
Data
Transmission
Stops
Key 22
Transmission
Data
Key 20&22
Transmission
Data
(H=Key-ON)
FIGURE 3. TRANSMISSION DATA DIAGRAM
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