NXP Semiconductors PCA9531PW,112

Overview

PCA9531PW,112 from NXP Semiconductors is an 8-bit I²C-bus LED dimmer IC with integrated oscillator, two programmable PWM blink rates (0.59–152 Hz), 256-step brightness control, and open-drain LED drivers sinking up to 25 mA per channel. It enables RGB color mixing and backlight dimming in compact displays and user-interface panels.

For engineers reviewing the PCA9531PW,112 datasheet, PCA9531PW,112 pinout, PCA9531PW,112 application, or PCA9531PW,112 equivalent, this device delivers deterministic LED timing control via register-programmable prescalers and PWM registers-critical for flicker-free illumination, synchronized multi-LED effects, and low-overhead I²C bus management in resource-constrained embedded systems.

Technical Context

The PCA9531PW,112 integrates a dedicated internal oscillator (no external components required) feeding two independent PWM channels (BLINK0/BLINK1), each controlled by a frequency prescaler (PSC0/PSC1) and duty-cycle register (PWM0/PWM1). Its I²C interface complies with SMBus electrical specifications and includes noise filtering on SCL/SDA inputs.

Each of the eight LEDn outputs operates as an open-drain driver capable of sinking 25 mA continuously (100 mA total package limit), while unused pins function as GPIOs with high-impedance, push-pull, or PWM-controlled output modes. Reset is handled via active-low RESET pin and Power-On Reset (VPOR = 1.7–2.2 V).

Key Specifications

Pinout & Package

TSSOP16 package (SOT403-1): plastic thin shrink small outline, 16 leads, 4.4 mm body width, 0.65 mm pitch, exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED dimmer applications.

Compared with TLC59116IPWPR and PCA9635PW,118, the PCA9531PW,112 offers optimal balance of simplicity, low pin count, and deterministic timing for 8-LED systems - minimizing firmware overhead while delivering production-ready flicker-free dimming without external timing components.

Availability

PCA9531PW,112 is available at Aetrix Electronics and suitable for industrial HMIs, smart appliance interfaces, and portable medical device backlights requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PCA9531PW,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in mixed-signal interface and power management ICs.

The PCA9531PW,112 belongs to NXP's I²C-bus I/O expander family, designed specifically to simplify LED control in space- and resource-constrained embedded systems while maintaining compatibility with legacy SMBus infrastructure.

FAQ

What is the maximum sink current per LED output on the PCA9531PW,112?

The PCA9531PW,112 supports up to 25 mA sink current per LEDn pin (LED0–LED7) under continuous DC conditions. The total package current must not exceed 100 mA. This rating assumes VDD ≥ 2.3 V and ambient temperature ≤ +85 °C, and is validated per NXP's static characteristics table (Table 12).

Can unused LED pins on the PCA9531PW,112 be repurposed as general-purpose inputs or outputs?

Yes - unused LEDn pins on the PCA9531PW,112 can operate as GPIOs. Configure the corresponding bit in LS0/LS1 registers to '00' for high-impedance input mode (readable via INPUT register), or '01' for active-low output. External pull-up resistors are required for output use, sized per the target load and VDD voltage.

Does the PCA9531PW,112 require external components to generate its PWM signals?

No - the PCA9531PW,112 contains a fully integrated oscillator with no external components required. Blink rates and duty cycles are set exclusively through I²C writes to the PSC0/PSC1 and PWM0/PWM1 registers, enabling self-contained, deterministic LED timing without MCU timer dependencies.

What I²C bus speeds does the PCA9531PW,112 support, and are there any timing constraints?

The PCA9531PW,112 supports Standard-mode (up to 100 kHz) and Fast-mode (up to 400 kHz) I²C operation. Dynamic characteristics (Table 13) specify tLOW/tHIGH minima, rise/fall time limits, and setup/hold times - all compliant with I²C specification v2.1. No additional timing margining is needed for standard bus implementations.

How does the PCA9531PW,112 handle power-on and hardware reset events?

On power-up, the PCA9531PW,112 performs Power-On Reset (POR) when VDD crosses VPOR (1.7–2.2 V), initializing all registers to defaults and setting outputs to high-impedance (LEDs off). An external active-low RESET pulse ≥6 ns forces identical initialization, holding registers and I²C state machine in reset until RESET returns high.