NXP Semiconductors PCA9553TK,118

Overview

The PCA9553TK,118 from NXP Semiconductors is a 4-bit I²C-bus LED blinker with integrated oscillator, designed to offload LED timing control from the host MCU in embedded systems. It provides two independent programmable blink rates (0.172–44 Hz), 25 mA per output sink capability, and supports GPIO expansion on unused LED pins. It operates across 2.3 V–5.5 V and is used in status indication for industrial HMIs, telecom equipment front panels, and IoT device power/communication LEDs.

For engineers reviewing the PCA9553TK,118 datasheet, PCA9553TK,118 pinout, PCA9553TK,118 application, or PCA9553TK,118 equivalent, key selection criteria include its fixed I²C address (0xC4), HVSON8 thermal-enhanced package, open-drain LED driver architecture, and dual-PWM blink rate independence-critical for reducing bus traffic and freeing MCU timer resources in resource-constrained designs.

Technical Context

The PCA9553TK,118 implements an internal oscillator with two independent prescaler/PWM register pairs (PSC0/PWM0 and PSC1/PWM1), enabling simultaneous blinking at distinct frequencies and duty cycles. Its LED selector register (LS0) assigns each of the four outputs to static ON/OFF or either blink mode without host intervention after initialization.

I²C interface logic complies with SMBus specifications, includes noise filtering on SCL/SDA, and supports standard- and fast-mode clocking up to 400 kHz. Power-on reset initializes all registers to default states, setting outputs high-impedance (LEDs off) and ensuring glitch-free startup.

Key Specifications

Pinout & Package

HVSON8 package: plastic thermal-enhanced very thin small outline, no leads, 8 terminals, body size 3 × 3 × 0.85 mm. Exposed center pad must be soldered to PCB thermal pad with vias for optimal thermal performance and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9554DP,118 and TLC59108IPWR, the PCA9553TK,118 uniquely delivers dual independent blink rates in a compact HVSON8 package-making it the only choice for applications requiring hardware-offloaded, differentiated LED timing without increasing MCU overhead or board area.

Availability

PCA9553TK,118 is available at Aetrix Electronics and suitable for industrial HMIs, telecom front panels, and IoT edge devices requiring stable component supply, long-term lifecycle support, and thermal-efficient packaging.

Supply support for PCA9553TK,118 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.

The PCA9553TK,118 belongs to NXP's I²C peripheral portfolio, engineered specifically to reduce host processor burden in LED-intensive embedded systems through autonomous timing control and minimal external component count.

FAQ

What is the I²C address of the PCA9553TK,118?

The PCA9553TK,118 uses the PCA9553/01 fixed I²C slave address: 0xC4 (1100010x, where R/W bit is separate). This allows co-location with PCA9553/02 (0xC6) on the same bus. The address is hardwired and not configurable via pins or registers-ensuring predictable addressing in multi-device systems without address conflicts.

Can unused LED pins on the PCA9553TK,118 be used as general-purpose inputs or outputs?

Yes. Unused LED pins on the PCA9553TK,118 can serve as GPIOs: configure as input by setting LS0 bits to high-impedance (01) and reading state via the INPUT register; configure as output by adding an external pull-up resistor and controlling drive state via LS0. No additional hardware is needed-leveraging the same pins for both LED and logic functions improves board density and reduces component count.

What are the maximum blink frequency and duty cycle ranges supported by the PCA9553TK,118?

The PCA9553TK,118 supports blink frequencies from 0.172 Hz (5.82 s period) to 44 Hz (23 ms period) and duty cycles from 0% to 100%, programmable independently for BLINK0 and BLINK1 via PSC0/PWM0 and PSC1/PWM1 registers. For example, BLINK0 can be set to 1 Hz/50% while BLINK1 runs at 4 Hz/25%-enabling complex visual status coding without host involvement.

Does the PCA9553TK,118 require external components for oscillator operation?

No. The PCA9553TK,118 integrates a precision internal oscillator-no external crystal, capacitor, or resistor is required to generate blink timing. This simplifies design, reduces bill-of-materials cost, and improves reliability by eliminating timing component drift, aging, or placement sensitivity. All timing parameters are digitally programmed via I²C registers.

How does the PCA9553TK,118 handle power-up sequencing and reset behavior?

On power-up, the PCA9553TK,118 performs an internal Power-On Reset (POR) that holds the device in reset until VDD reaches VPOR (1.7–2.2 V), then initializes all registers to default values-including LS0 set to 01 (LEDs off/high-Z) and blink registers preset to 44 Hz/50%. This ensures glitch-free startup and predictable LED state-critical for safety-critical or user-facing applications where unintended illumination must be avoided.