NXP 2/4/8/16-bit I2C/SMBus LED blinkers PCA9550/51/52/53 LED blinking with GPIO expansion These I2C/SMBus-compatible GPIO expanders, optimized for blinking in LED-status applications, support two user-programmable blink rates, without overloading the I2C-bus or tying up the I2Cbus master. Key features 4 Compatible with I2C-bus and SMBus 4 Two user-programmable blink rates and duty cycles – Blink rate: 0.025 to 6.4 sec (40 to 0.156 Hz) – Duty cycle: 0.4 to 100% 4 Internal oscillator accurate to ±10% and requires no external components 4 Open-drain outputs can drive LEDs directly (25 mA max sink per bit) 4 High maximum device limits (50, 100, or 200 mA) 4 I/O states readable via I2C/SMBus 4 Any bit not used to drive an LED can be used as normal GPIO 4 Active-low hardware reset saves power and simplifies design 4 Low standby current (ISTB): 1.5 µA (max) 4 Operating voltage: 2.3 to 5.5 V 4 All I/O tolerant to 5.5 V 4 Temperature range: -40 to +85 °C 4 I2C-bus clock frequency: 0 to 400 kHz 4 ESD protection exceeds JEDEC standards 4 High-volume CMOS process 4 Package options: SO, TSSOP, HVQFN Applications 4 LED status The NXP PCA9550, PCA9551, PCA9552, and PCA9553 are used to blink LEDs in I2C-bus and SMBus applications. Each LED can be on, off, or flashing at one of two programmable rates without overloading the I2C-bus or tying up the I2C-bus master. The blink rate can vary from 0.025 to 6.4 seconds (40 to 0.156 Hz) in 256 steps. The duty cycle is programmable in 256 steps, for flexible on and off times. There can be a short flash of light, for example, or long on periods with a very short off period. Any bits that aren’t used to control LEDs can be used as general-purpose I/O (GPIO), for a quick, easy to add sensors, push-buttons, alarm monitors, LEDs, fans, and more. On the PCA9551 and PCA9552, three hardware pins (A0, A1, A2) let up to eight identical devices share the same I2C/SMBus. On the PCA9550, a single hardware pin (A0), supports up to two devices on the same I2C/SMBus. Due to hardware pin limitations, the PCA9553 doesn’t have address pins so the address is fixed. 2 LED1 3 VSS 4 16 VDD A0 1 16 VDD 15 SDA A1 2 15 SDA 14 SCL A2 3 14 SCL LED0 4 LED1 5 LED2 6 LED3 7 10 LED5 VSS 8 9 13 RESET SLAVE ADDRESS 1 1 0 0 0 FIXED 0 A0 R/W PROGRAMMABLE 13 RESET 12 LED7 11 LED6 LED4 SLAVE ADDRESS PCA9550 1 Except for the number of bits and address pins, the functional diagram and I/O schematic are the same for all of the devices. A0 1 24 VCC A1 2 23 SDA 1 0 3 22 SCL 4 21 RESET LED1 5 20 LED15 LED2 6 LED3 7 LED4 8 LED5 9 16 LED11 LED0 1 LED6 10 15 LED10 LED1 2 LED7 11 14 LED9 LED2 3 VSS 12 13 LED8 VSS 4 0 FIXED A2 A0 R/W PROGRAMMABLE 19 LED14 18 LED13 17 LED12 16 VDD 15 SDA 14 SCL 13 LED3 SLAVE ADDRESS SLAVE ADDRESS 0 A1 PCA9551 A2 1 A2 FIXED LED0 1 0 PCA9553 ESD protection exceeds 2000 V HBM per JESD22-A114, 150 V MM per JESD22-A115, and 1000 V CDM per JESD22-C101. JESDEC Standard JESD78 latch-up testing exceeds 100 mA. More information on NXP LED blinkers can be found in application note AN264. PCA9551 1 PCA9552 On the PCA9550, PCA9551, and PCA9552, an external activelow reset hardware pin (RESET) returns registers to their default states, without having to cycle power to the equipment, if the I2C-bus locks up. A0 LED0 PCA9550 Each device features open-drain outputs that sink 25 mA per bit. The PCA9550 supports a maximum of 50 mA, the PCA9551 and PCA9553 a maximum of 100 mA, and the PCA9552 a maximum of 200 mA (100 mA per 8-bit group). A1 A0 1 R/W 1 0 0 0 1 0 R/W FIXED PROGRAMMABLE PCA9553/01 PCA9552 Pin configuration A2 A1 A0 3.3 V INPUT REGISTER SCL SDA INPUT FILTERS PC BUS CONTROL LEDs LED SELECT (LSx) REGISTER VCC SDA SDA LED0 SCL SCL LED1 RESET 0 VDD RESET LED3 1 POWER ON RESET PRESCALER 0 REGISTER PRESCALER 1 REGISTER OSCILLATOR LED2 LED4 LEDs PWM0 REGISTER BLINK0 PWM1 REGISTER BLINK1 BUS MASTER A0 LED5 A1 LED6 A2 GPIO LED7 VSS VSS Note: only one I/D shown for clarity Block diagram PCA9551 Typical application Order information Package Container PCA9550 PCA9551 PCA9552 PCA9553/01 SO Tube T&R PCA9550D PCA9550D-T PCA9551D PCA9551D-T PCA9552D PCA9552D-T PCA9553D/01 PCA9553D-T/01 TSSOP Tube T&R PCA9550DP-T PCA9551PW PCA9551DP-T PCA9552PW PCA9552DP-T PCA9553DP/01-T HVQFN T&R PCA9551BS-T PCA9552BS-T www.nxp.com © 2007 NXP N.V. All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The Date of release: June 2007 information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and Document order number: 9397 750 16021 may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof Printed in the USA does not convey nor imply any license under patent or other industrial or intellectual property rights.