Overview
The PCA9955BTW/Q900J, produced by NXP USA Inc., is a highly advanced 16-channel constant current LED driver. This device is optimized for dimming and blinking Red/Green/Blue/Amber (RGBA) LEDs, particularly in applications such as amusement products. It features an I²C-bus interface for precise control over each LED channel, allowing for individual and group dimming and blinking with high precision.
Key Specifications
| Specification | Value |
|---|---|
| Number of Channels | 16 |
| Output Current per Channel | Up to 57 mA |
| LED Supply Voltage | Up to 20 V |
| Supply Voltage Range | 3 V to 5.5 V |
| PWM Frequency (Individual) | 31.25 kHz |
| PWM Frequency (Group) | 122 Hz (adjustable from 15 Hz to 16.8 seconds) |
| PWM Resolution | 8-bit (256 steps) |
| I²C-bus Interface | Fast-mode Plus (Fm+), up to 1 MHz |
| Operating Temperature | -40°C to +105°C |
| Package Type | HTSSOP28 |
| Environmental Compliance | PbFree, EU RoHS, Halogen Free, REACH SVHC compliant |
Key Features
- Individual and group PWM control with 8-bit resolution (256 steps) for each LED output and group.
- Adjustable output peak current from 225 µA to 57 mA using an 8-bit linear DAC.
- Gradation control with four independently programmable groups, each with ramp-up, ramp-down, step time, hold ON/OFF time, and final hold ON output current settings.
- Built-in open, short load, and overtemperature detection with thermal shutdown protection.
- Active LOW output enable input pin for external PWM control.
- Software programmable LED groups and three Sub Call I²C-bus addresses for flexible addressing.
- Software Reset (SWRST) function through the I²C-bus.
- No external components required for the 8 MHz internal oscillator.
- No glitch on LED outputs on power-up and low standby current.
Applications
The PCA9955BTW/Q900J is particularly suited for applications requiring precise control over multiple LEDs, such as:
- Amusement products (e.g., gaming machines, arcade games).
- Display panels and signage.
- Automotive lighting systems.
- Consumer electronics with LED lighting (e.g., TVs, monitors).
- Industrial lighting and control systems.
Q & A
- What is the maximum output current per channel for the PCA9955BTW/Q900J?
The maximum output current per channel is up to 57 mA. - What is the supply voltage range for the PCA9955BTW/Q900J?
The supply voltage range is from 3 V to 5.5 V. - What type of I²C-bus interface does the PCA9955BTW/Q900J use?
The device uses a Fast-mode Plus (Fm+) I²C-bus interface, capable of up to 1 MHz frequency. - How many channels can be controlled by the PCA9955BTW/Q900J?
The device can control 16 LED channels. - What is the PWM frequency for individual LED channels?
The PWM frequency for individual LED channels is 31.25 kHz. - Can the PCA9955BTW/Q900J detect errors such as open or short loads?
Yes, the device has built-in open, short load, and overtemperature detection circuitry. - How many devices can be connected on the same I²C-bus?
Up to 125 devices can be connected on the same I²C-bus using the three hardware address pins. - What is the purpose of the Software Reset (SWRST) function?
The Software Reset function allows the device to be reset through the I²C-bus, similar to a Power-On Reset, to reconfigure all device registers to their default state. - Does the PCA9955BTW/Q900J require external components for its internal oscillator?
No, the device has an 8 MHz internal oscillator that requires no external components. - What is the operating temperature range for the PCA9955BTW/Q900J?
The operating temperature range is from -40°C to +105°C.
