Philips pca8521 DATASHEETS

INTEGRATED CIRCUITS

DATA SHEET

PCA8521

Infrared remote control transmitter RC5

Product specification

1999 Jun 15

Supersedes data of 1997 Jul 03

File under Integrated Circuits, IC02

Philips Semiconductors	Product specification
Infrared remote control transmitter RC5	PCA8521

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.

ORDERING INFORMATION

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. The oscillator frequency may be optionally chosen as 432 kHz or 4 MHz. For 432 kHz additional external capacitors must be connected. The capacitors for a 4 MHz oscillator is integrated. When a key in the key-matrix is pressed a drive line 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.

Seven drive lines (DR0 to DR6) and eight sense lines (SN0 to SN7) may be connected via the key matrix to scan the keys (see Fig.1).

When two or more keys are activated simultaneously no transmission will take place.

TYPE		PACKAGE
NUMBER	NAME	DESCRIPTION	VERSION
PCA8521FP	DIP16	plastic dual in-line package; 16 leads (300 mil)	SOT38-4
PCA8521FT	SO16	plastic small outline package; 16 leads; body width 7.5 mm	SOT162-1
PCA8521BP	DIP20	plastic dual in-line package; 20 leads (300 mil)	SOT146-1
PCA8521BT	SO20	plastic small outline package; 20 leads; body width 7.5 mm	SOT163-1

1999 Jun 15

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Philips Semiconductors	Product specification
Infrared remote control transmitter RC5	PCA8521
BLOCK DIAGRAM

		432 kHz or 4 MHz
		XTAL1	XTAL2
		1	2
			TIMING GENERATOR
		OSCILLATOR		AND
			CONTROL
		STOP		36 kHz
SN0	4
	5
SN1
	6
SN2			1K x 8	PULSE	OUTPUT	19
	7
SN3			ROM	GENERATOR	DRIVER	LOUT
	9
SN4
	10
SN5
	8
SN6
	3		KEY
SN7
	16	SCANNING
DR0
	15
DR1			SHIFT REGISTER
	14
DR2
	13
DR3
	12			PCA8521
DR4
	11
DR5
	17
DR6
			20	18
			VDD	VSS	MBH038

Fig.1 Block diagram (for DIP20 and SO20 packages).

1999 Jun 15

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Philips Semiconductors	Product specification
Infrared remote control transmitter RC5	PCA8521

PINNING

16-pin dual in-line and small outline package

	SYMBOL			PIN	DESCRIPTION
	XTAL1			1	oscillator input
	XTAL2			2	oscillator output
	SN0			3	sense line 0 for key matrix
	SN1			4	sense line 1 for key matrix
	SN2			5	sense line 2 for key matrix
	SN3			6	sense line 3 for key matrix
	SN4			7	sense line 4 for key matrix
	SN5			8	sense line 5 for key matrix
				9	drive line 4 for key matrix
	DR4
					(active LOW)
				10	drive line 3 for key matrix
	DR3
					(active LOW)
				11	drive line 2 for key matrix
	DR2
					(active LOW)
				12	drive line 1 for key matrix
	DR1
					(active LOW)
				13	drive line 0 for key matrix
	DR0
					(active LOW)
	VSS			14	ground
				15	output signal (active LOW)
	LOUT
	VDD			16	power supply

handbook, halfpage

XTAL1	1			16				VDD
XTAL2	2				15			LOUT
SN0								VSS
	3				14
SN1	4		PCA8521		13			DR0
SN2	5				12			DR1
SN3	6				11			DR2
SN4	7				10			DR3
SN5	8				9			DR4
			MBH032

Fig.2 Pin configuration (DIP/SO16).

1999 Jun 15

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Philips Semiconductors	Product specification
Infrared remote control transmitter RC5	PCA8521

20-pin dual in-line and small outline package

	SYMBOL			PIN	DESCRIPTION
	XTAL1			1	oscillator input
	XTAL2			2	oscillator output
	SN7			3	sense line 7 for key matrix
	SN0			4	sense line 0 for key matrix
	SN1			5	sense line 1 for key matrix
	SN2			6	sense line 2 for key matrix
	SN3			7	sense line 3 for key matrix
	SN6			8	sense line 6 for key matrix
	SN4			9	sense line 4 for key matrix
	SN5			10	sense line 5 for key matrix
				11	drive line 5 for key matrix
	DR5
					(active LOW)
				12	drive line 4 for key matrix
	DR4
					(active LOW)
				13	drive line 3 for key matrix
	DR3
					(active LOW)
				14	drive line 2 for key matrix
	DR2
					(active LOW)
				15	drive line 1 for key matrix
	DR1
					(active LOW)
				16	drive line 0 for key matrix
	DR0
					(active LOW)
				17	drive line 6 for key matrix
	DR6
					(active LOW)
	VSS			18	ground
				19	output signal (active LOW)
	LOUT
	VDD			20	power supply

handbook, halfpage

XTAL1	1			20			VDD
XTAL2	2				19		LOUT
							VSS
SN7	3				18
SN0	4				17		DR6
SN1	5		PCA8521		16		DR0
SN2	6				15		DR1
SN3	7				14		DR2
SN6	8				13		DR3
SN4	9				12			DR4
SN5	10				11			DR5
			MBH033

Fig.3 Pin configuration (DIP/SO20).

1999 Jun 15

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Philips Semiconductors	Product specification
Infrared remote control transmitter RC5	PCA8521
FUNCTIONAL DESCRIPTION
Key numbering for the matrix is given in Tables 1 and 2.

Table 1 Key numbering for 16-pin package

	DRIVER									SENSE LINES
	LINES			SN0			SN1			SN2	SN3		SN4				SN5
				0			1		2		3		4			5
	DR0
				8			9		10		11		12			13
	DR1
				16			17		18		19		20			21
	DR2
				24			25		26		27		28			29
	DR3
				32			33		34		35		36			37
	DR4
Table 2 Key numbering for 20-pin package
	DRIVER									SENSE LINES
	LINES			SN0		SN1		SN2		SN3	SN4		SN5		SN6		SN7
				0		1		2		3	4		5		6		7
	DR0
				8		9		10		11	12		13		14		15
	DR1
				16		17		18		19	20		21		22		23
	DR2
				24		25		26		27	28		29		30		31
	DR3
				32		33		34		35	36		37		38		39
	DR4
				40		41		42		43	44		45		46		47
	DR5
				48		49		50		51	52		53		54		55
	DR6

When the keys have been scanned the key-number of the activated key serves as the address of the ROM to obtain the required code-word. When a 16-pin IC is used the following sense lines and driver lines will not be connected; SN6, SN7, DR5 and DR6. Consequently, key numbers 6, 7, 14, 15, 22, 23, 30, 31, 38, 39 and 40 to 55 will not be addressed.

The ROM contains 8 banks of 64 code-words. Thus for each key a maximum of 8 different code-words may be generated. With multi-system use, 8 different systems (e.g. TV, VCR, tuner, CD etc.) may be selected. Apart from the system bits the command bits may also be different in different banks (true multi-function keys). Selection can be performed using the keys. For each key three bank select bits are present that determine which bank will be selected for the next key.

For each key an ‘inhibit’ bit is also present. When this bit is at logic 1 at an address in a given bank, and when the corresponding key is pressed (when this bank has been selected) no transmission will take place.

A single system option is available however, whereby instead of keys a jumper wire and/or a switch may be used for bank selection. Using this option it is possible to program different transmitter models in one IC and select the required bank by means of a jumper wire. Instead of a jumper wire a side-switch may also be used to change the generated code temporarily (select different bank) to obtain multi-function keys. With this option the jumper wires or switch must be connected between sense line SN0 and one of the drive lines DR0 to DR6 or ground. This means that SN0 cannot be used to connect keys and the maximum number of keys will be 25 keys for a 16-pin package and 49 keys for a 20-pin package.

It is not possible to use a combination of jumper wires and selection keys for bank selection in one unit.

The output of the ROM is loaded into a shift register that provides the input bits for the pulse generator. This pulse generator drives the output pin.

1999 Jun 15

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