GENERAL DESCRIPTION
The PCA8521 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. An example of an application diagram using a 20-pin IC is illustrated in Fig.7.

FEATURES
• RC5 protocol
• Maximum of:
– 56 keys (20-pin version)
– 30 keys (16-pin version).
• Option of multi-system or single system transmitter
– Multi-system: maximum 8 systems, 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 (≤45 mA)
• Oscillator frequency of 432 kHz or 4 MHz
• Multiple key protection
• Option of 25% or 33% duty factor
• Contained in DIP16, SO16, DIP20 or SO20 packages.