PCA9685 datasheet(2/50 Pages) NXP

2 / 50 page

PCA9685_2

Product data sheet

Rev. 02 — 16 July 2009

2 of 50

NXP Semiconductors

PCA9685

16-channel, 12-bit PWM Fm+ I2C-bus LED controller

The active LOW Output Enable input pin (OE) allows asynchronous control of the LED

outputs and can be used to set all the outputs to a deﬁned I2C-bus programmable logic

state. The OE can also be used to externally ‘pulse width modulate’ the outputs, which is

useful when multiple devices need to be dimmed or blinked together using software

control.

Software programmable LED All Call and three Sub Call I2C-bus addresses allow all or

deﬁned groups of PCA9685 devices to respond to a common I2C-bus address, allowing

for example, all red LEDs to be turned on or off at the same time or marquee chasing

effect, thus minimizing I2C-bus commands. Six hardware address pins allow up to

62 devices on the same bus.

The Software Reset (SWRST) General Call allows the master to perform a reset of the

PCA9685 through the I2C-bus, identical to the Power-On Reset (POR) that initializes the

registers to their default state causing the outputs to be set LOW. This allows an easy and

quick way to reconﬁgure all device registers to the same condition via software.

Features

I 16 LED drivers. Each output programmable at:

N Off

N On

N Programmable LED brightness

N Programmable LED turn-on time to help reduce EMI

I 1 MHz Fast-mode Plus compatible I2C-bus interface with 30 mA high drive capability

on SDA output for driving high capacitive buses

I 4096-step (12-bit) linear programmable brightness per LED output varying from fully

off (default) to maximum brightness

I LED output frequency (all LEDs) typically varies from 40 Hz to 1000 Hz (Default of 1Eh

in PRE_SCALE register results in a 200 Hz refresh rate with oscillator clock of

25 MHz.)

I Sixteen totem pole outputs (sink 25 mA and source 10 mA at 5 V) with software

programmable open-drain LED outputs selection (default at totem pole). No input

function.

I Output state change programmable on the Acknowledge or the STOP Command to

update outputs byte-by-byte or all at the same time (default to ‘Change on STOP’).

I Active LOW Output Enable (OE) input pin. LEDn outputs programmable to logic 1,

logic 0 (default at power-up) or ‘high-impedance’ when OE is HIGH.

I 6 hardware address pins allow 62 PCA9685 devices to be connected to the same

I2C-bus

I Toggling OE allows for hardware LED blinking

I 4 software programmable I2C-bus addresses (one LED All Call address and three LED

Sub Call addresses) allow groups of devices to be addressed at the same time in any

combination (for example, one register used for ‘All Call’ so that all the PCA9685s on

the I2C-bus can be addressed at the same time and the second register used for three

different addresses so that 1

⁄

3 of all devices on the bus can be addressed at the same

time in a group). Software enable and disable for these I2C-bus address.

I Software Reset feature (SWRST General Call) allows the device to be reset through

the I2C-bus

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