PCA9955TW,118

LED Driver 3.3V/5V 28Pin HTSSOP EP T/R

Overview

The PCA9952 and PCA9955 are I²C-bus controlled 16-channel constant current LED driver optimized for dimming and blinking 57 mA Red/Green/Blue/Amber RGBA LEDs in amusement products. Each LEDn output has its own 8-bit resolution 256 steps fixed frequency individual PWM controller that operates at 31.25 kHz with a duty cycle that is adjustable from 0 % to 99.6 % to allow the LED to be set to a specific brightness value. An additional 8-bit resolution 256 steps group PWM controller has both a fixed frequency of 122 Hz and an adjustable frequency between 15 Hz to once every 16.8 seconds with a duty cycle that is adjustable from 0 % to 99.6 % that is used to either dim or blink all LEDs with the same value.

Each LEDn output can be off, on no PWM control, set at its individual PWM controller value or at both individual and group PWM controller values. The PCA9952 and PCA9955 operate with a supply voltage range of 3 V to 5.5 V and the constant current sink LEDn outputs allow up to 40 V for the LED supply. The output peak current is adjustable with an 8-bit linear DAC from 225 µA to 57 mA.

These devices have built-in open, short load and overtemperature detection circuitry. The error information from the corresponding register can be read via the I²C-bus. Additionally, a thermal shutdown feature protects the device when internal junction temperature exceeds the limit allowed for the process.

The PCA9952 and PCA9955 devices have Fast-mode Plus Fm+ I²C-bus interface. Fm+ devices offer higher frequency up to 1 MHz or more densely populated bus operation up to 4000 pF.

The PCA9952 is identical to PCA9955 except for the following differences:

* The PCA9952 has only three hardware address pins compared to four on PCA9955.

* The PCA9952 has an output enable pin OE and the PCA9955 does not.

The active LOW output enable input pin OE, available only on PCA9952, blinks all the LEDn outputs and can be used to externally PWM the outputs, which is useful when multiple devices need to be dimmed or blinked together without using software control.

Software programmable LED Group and three Sub Call I²C-bus addresses allow all or defined groups of PCA9952/55 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. On power-up, PCA9952/55 will have a unique Sub Call address to identify it as a 16-channel LED driver. This allows mixing of devices with different channel widths. Four hardware address pins on PCA9955 allow up to 16 devices on the same bus. In the case of PCA9952, three hardware address pins allow up to 8 devices on the same bus.

The Software Reset SWRST function allows the master to perform a reset of the PCA9952/55 through the I²C-bus, identical to the Power-On Reset POR that initializes the registers to their default state causing the output current switches to be OFF LED off. This allows an easy and quick way to reconfigure all device registers to the same condition.

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## Features

* 16 LED drivers. Each output programmable at:

* Off

* On

* Programmable LED brightness

* Programmable group dimming/blinking mixed with individual LED brightness

* Programmable LEDn output enable delay to reduce EMI and surge currents

* 16 constant current output channels can sink up to 57 mA, tolerate up to 40 V when OFF

* Output current adjusted through an external resistor

* Output current accuracy

* ±6 % between output channels

* ±8 % between PCA9952/55 devices

* Open/short load/overtemperature detection mode to detect individual LED errors

* 1 MHz Fast-mode Plus compatible I²C-bus interface with 30 mA high drive capability on SDA output for driving high capacitive buses

* 256-step 8-bit linear programmable brightness per LEDn output varying from fully off default to maximum brightness using a 31.25 kHz PWM signal

* 256-step group brightness control allows general dimming using a 122 Hz PWM signal from fully off to maximum brightness default

* 256-step group blinking with frequency programmable from 15 Hz to 16.8 s and duty cycle from 0 % to 99.6 %

* 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’.

* Active LOW Output Enable OE input pin only on PCA9952 allows for hardware blinking and dimming of the LEDs

* Four hardware address pins allow 16 PCA9955 devices to be connected to the same I²C‑bus and to be individually programmed

* Four software programmable I²C-bus addresses one LED Group 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 PCA9952/55s 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 each programmable I²C‑bus address.

* Unique power-up default Sub Call address allows mixing of devices with different channel widths

* Software Reset feature SWRST Call allows the device to be reset through the I²C‑bus

* 8 MHz internal oscillator requires no external components

* Internal power-on reset

* Noise filter on SDA/SCL inputs

* No glitch on LED on power-up

* Low standby current

* Operating power supply voltage VDD range of 3 V to 5.5 V

* 5.5 V tolerant inputs on non-LED pins

* Operating temperature:

* -20 °C to +85 °C PCA9952TW, PCA9955TW

* -40 °C to +85 °C PCA9952TW/Q900, PCA9955TW/Q900

* ESD protection exceeds 2000 V HBM per JESD22-A114, 750 V CDM PCA9952TW, PCA9955TW, and 500 V CDM PCA9952TW/Q900, PCA9955TW/Q900 per JESD22-C101

* Latch-up testing is done to JEDEC Standard JESD78 Class II, Level B

* Packages offered: HTSSOP28

## Target Applications

* Amusement products

* RGB or RGBA LED drivers

* LED status information

* LED displays

* LCD backlights

* Keypad backlights for cellular phones or handheld devices

* Automotive lighting PCA9952TW/Q900, PCA9955TW/Q900

## Features