PCA9530 2 2-bit I C-bus LED dimmer Rev. 03 26 February 2009 Product data sheet 1. General description 2 The PCA9530 is a 2-bit I C-bus and SMBus I/O expander optimized for dimming LEDs in 256 discrete steps for Red/Green/Blue (RGB) color mixing and backlight applications. The PCA9530 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 50 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 active LOW hardware reset pin (RESET) and Power-On Reset (POR) initialize the registers to their default state causing the bits to be set HIGH (LED off). One hardware address pin on the PCA9530 allows two devices to operate on the same bus. 2. Features n 2 LED drivers (on, off, ashing at a programmable rate) n 2 selectable, fully programmable blink rates (frequency and duty cycle) between 0.591 Hz and 152 Hz (1.69 seconds and 6.58 milliseconds) n 256 brightness steps n Input/output not used as LED drivers can be used as regular GPIOs n Internal oscillator requires no external components 2 n I C-bus interface logic compatible with SMBus n Internal power-on resetPCA9530 NXP Semiconductors 2 2-bit I C-bus LED dimmer n Noise lter on SCL/SDA inputs n Active LOW reset input (RESET) n 2 open-drain outputs directly drive LEDs to 25 mA n Edge rate control on outputs n No glitch on power-up n Supports hot insertion n Low standby current n Operating power supply voltage range of 2.3 V to 5.5 V n 0 Hz to 400 kHz clock frequency n ESD protection exceeds 2000 V HBM per JESD22-A114, 150 V MM per JESD22-A115 and 1000 V CDM per JESD22-C101 n Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA n Packages offered: SO8, TSSOP8 (MSOP8) 3. Ordering information Table 1. Ordering information T = - 40 C to +85 C amb Type number Topside Package mark Name Description Version PCA9530D PCA9530 SO8 plastic small outline package 8 leads body width 3.9 mm SOT96-1 1 PCA9530DP 9530 TSSOP8 plastic thin shrink small outline package 8 leads body width 3 mm SOT505-1 1 Also known as MSOP8. 4. Block diagram A0 PCA9530 INPUT REGISTER 2 SCL INPUT I C-BUS LED SELECT (LSn) FILTERS CONTROL REGISTER SDA 0 V 1 DD POWER-ON LEDn RESET RESET BLINK0 PRESCALER 0 PWM0 REGISTER REGISTER BLINK1 PRESCALER 1 PWM1 OSCILLATOR REGISTER REGISTER V SS 002aae498 Remark: Only one I/O shown for clarity. Fig 1. Block diagram PCA9530 3 NXP B.V. 2009. All rights reserved. Product data sheet Rev. 03 26 February 2009 2 of 24