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