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PCA9533: 4-bit I2C-bus LED dimmer

The PCA9533 is a 4-bit I²C-bus and SMBus I/O expander optimized for dimming LEDs in 256 discrete steps for Red/Green/Blue (RGB) color mixing and back light applications.

The PCA9533 contains an internal oscillator with two user programmable blink rates and duty cycles coupled to the output PWM. The LED brightness is controlled by setting the blink rate high enough (> 100 Hz) that the blinking cannot be seen and then using the duty cycle to vary the amount of time the LED is on and thus the average current through the LED.

The initial setup sequence programs the two blink rates/duty cycles for each individual PWM. From then on, only one command from the bus master is required to turn individual LEDs ON, OFF, BLINK RATE 1 or BLINK RATE 2. Based on the programmed frequency and duty cycle, BLINK RATE 1 and BLINK RATE 2 will cause the LEDs to appear at a different brightness or blink at periods up to 1.69 second. The open-drain outputs directly drive the LEDs with maximum output sink current of 25 mA per bit and 100 mA per package.

To blink LEDs at periods greater than 1.69 second the bus master (MCU, MPU, DSP, chip set, etc.) must send repeated commands to turn the LED on and off as is currently done when using normal I/O expanders like the NXP Semiconductors PCF8574 or PCA9554. Any bits not used for controlling the LEDs can be used for General Purpose parallel Input/Output (GPIO) expansion, which provides a simple solution when additional I/O is needed for ACPI power switches, sensors, push-buttons, alarm monitoring, fans, etc.

The Power-On Reset (POR) initializes the registers to their default state, causing the bits to be set HIGH (LED off).

Due to pin limitations, the PCA9533 is not featured with hardware address pins. The PCA9533/01 and the PCA9533/02 have different fixed I²C-bus addresses allowing operation of both on the same bus.

PCA9533: Product Block Diagram

sot096-1_3d

Data Sheets (1)

Application Notes (1)

Users Guides (3)

Brochures (4)

Package Information (2)

Packing (2)

Supporting Information (4)

IBIS Model

• PCA9533 IBIS model (REV 1.0) ZIP PCA9533_1 8/26/2014

Ordering Information

Package Information

Product ID	Package Description	Outline Version	Reflow/Wave Soldering	Packing	Product Status	Part NumberOrdering code(12NC)	Marking	Chemical Content	RoHS / Pb Free / RHF	LeadFree Conversion Date	EFR	IFR(FIT)	MTBF(hour)	MSL	MSL LF
PCA9533D/01		SOT96-1	SO-SOJ-REFLOW SO-SOJ-WAVE SO-SOJ-REFLOW SO-SOJ-WAVE	Reel 13" Q1/T1	Active	PCA9533D/01,118 (9352 744 34118)	P9533/1	PCA9533D/01		week 5, 2005	0.0	2.0	5E8	1	1
				Bulk Pack	Active	PCA9533D/01,112 (9352 744 34112)	P9533/1	PCA9533D/01		week 5, 2005	0.0	2.0	5E8	1	1
PCA9533D/02		SOT96-1	SO-SOJ-REFLOW SO-SOJ-WAVE SO-SOJ-REFLOW SO-SOJ-WAVE	Reel 13" Q1/T1	Active	PCA9533D/02,118 (9352 744 36118)	P9533/2	PCA9533D/02		week 5, 2005	0.0	2.0	5E8	1	1
				Bulk Pack	Active	PCA9533D/02,112 (9352 744 36112)	P9533/2	PCA9533D/02		week 5, 2005	0.0	2.0	5E8	1	1
PCA9533DP/01		SOT505-1	Reflow_Soldering_Profile	Reel 13" Q1/T1	Active	PCA9533DP/01,118 (9352 744 35118)	P33/1	PCA9533DP/01		week 12, 2005	0.0	2.0	5E8	1	1
PCA9533DP/02		SOT505-1	Reflow_Soldering_Profile	Reel 13" Q1/T1	Active	PCA9533DP/02,118 (9352 744 37118)	P33/2	PCA9533DP/02		week 12, 2005	0.0	2.0	5E8	1	1