SC9012 Silan Microelectronics Joint-stock, SC9012 Datasheet - Page 3

• Manufacturer Part Number: SC9012
• Description: INFRARED REMOTE CONTROL TRANSMITTER
• Manufacturer: Silan Microelectronics Joint-stock

FUNCTIONAL DESCRIPTION
1. OSCILLATION CIRCUIT
between OSCO and OSCI. Please refer to the follow diagram. Unless the keys are being operated, the oscillation is
normally stopped. Thus, power consumption is considerably reduced.
2. OSCILLATION FREQUENCY
The oscillator frequency is 455kHz, passed by a 12 division frequency circuit, can get a 37.9 ~ 39.2 frequency; 1/3
duty carrier. In addition, The oscillator frequency divided by 256, can get the basic system work time (1.78kHz). The
relation of carrier frequency (fc), internal work time period (Tm) and oscillator frequency (fosc) is given below:
3. KEY
Key Inputs -- KI0~KI3 of SC9012 have built-in pull-down resistors, which combined 32 keys matrix with Key Outputs
--KO0~KO7. Except the stated 6 double keys, Pressing other keys that are NOT intended for the double key
operation do NOT generate any output. Please refer to the follow diagram for the keys input matrix of SC9012.
An oscillator circuit may be constructed by connecting a 480kHz or 455kHz Crystal Resonator and two capacitors
fc = 1/12
Tm = 256 / fosc
MATRIX
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Silan
Semiconductors
fosc
Tm the width of a high level pulse .
duty 1/3
KI0
KI1
KI2
KI3
100pf
1
2
3
4
OSCI
5
6
7
8
9
10
11
12
SC9012
9
455kHz
3
13
14
15
16
17
18
19
20
OSCO
8
21
22
23
24
100pf
25
26
27
28
29
30
31
32
SC9012
Rev: 2.1
2002-02-28