DESCRIPTION
The SC8521 can be used in infrared remote control transmitters. It generates output pulses, in accordance with the RC5 protocol, when a key is pressed. The IC does not contain a software programmable processor. However, it does contain a ROM in which the codes that have to be transmitted are stored. The oscillator frequency may be optionally chosen as 432KHz. For 432KHz additional external capacitors must be connected. When a key in the key-matrix is pressed a driveline will be connected to a sense line. This causes the oscillator to start and a corresponding code will be generated conforming to the RC5 protocol.

FEATURES
∗ RC5 protocol
∗ Maximum of 56 keys (20-pin version)
∗ Option of multi-system or single system transmitter
    -- Multi-system: maximum 8 system, selection by key
    -- Single system: maximum 8 different systems per IC, selection by jumper wire or switch.
∗ Power-down and key wake-up
∗ High output current (≤45mA)
∗ Oscillator frequency of 432KHz
∗ Multiple key protection
∗ Option of 25% or 33% duty factor