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NXP Semiconductors PCAL9554CBS,128
- Part No.:
- PCAL9554CBS,128
- Manufacturer:
- NXP Semiconductors
- Category:
- I/O Expanders
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
PCAL9554CBS,128.pdf
- Description:
- IC XPND 400KHZ I2C SMBUS 16HVQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,965
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Product details
Overview
PCAL9554CBS,128 from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander with Agile I/O features, interrupt output, and programmable pull-up/pull-down resistors. It operates from 1.65 V to 5.5 V, supports 400 kHz Fast-mode I²C, delivers 25 mA sink per I/O, and powers up with all pins configured as inputs - enabling reliable board bring-up in ACPI power switches, LED control, fan management, and sensor interface applications.
For engineers reviewing the PCAL9554CBS,128 datasheet, PCAL9554CBS,128 pinout, PCAL9554CBS,128 application, or PCAL9554CBS,128 equivalent, this device offers verified interrupt masking, latchable inputs, programmable output drive strength, and hardware address selection via A0–A2 - critical for multi-device I²C systems requiring deterministic interrupt handling and flexible I/O configuration without layout changes.
Technical Context
The PCAL9554CBS,128 implements a dual-register architecture: standard PCA9554A-compatible registers (Input/Output/Configuration/Polarity Inversion) plus Agile I/O extended registers (Output Drive Strength, Input Latch, Pull-up/Pull-down Enable/Selection, Interrupt Mask/Status, Output Port Configuration). Its interrupt logic responds to input state changes only when unmasked and latched, with INT de-assertion tied to Input Port register reads - ensuring deterministic edge detection and eliminating spurious interrupts at power-up.
All 8 I/Os support 5 V tolerance and configurable push-pull or open-drain output stages per bank; each I/O's drive strength is independently set to 25 %, 50 %, 75 %, or 100 % of full capability via two-bit control; internal Schmitt-trigger inputs provide 0.10 × VDD hysteresis for noise immunity on SCL/SDA and port lines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Bus Speed | 400 kHz Fast-mode - enables high-throughput I/O expansion without slowing system bus performance. |
| Supply Voltage Range | 1.65 V to 5.5 V - interoperates with mixed-voltage systems including 1.8 V, 3.3 V, and 5 V microcontrollers. |
| Interrupt Output | Open-drain active-low INT - requires external pull-up but allows wired-OR sharing across multiple expanders on one interrupt line. |
| Output Sink Current | 25 mA per I/O - directly drives LEDs or small loads without external buffers. |
| Input Hysteresis | 0.10 × VDD (typical) - rejects noise on slow-rising/falling signals and improves robustness in electrically noisy environments. |
| ESD Protection | 2000 V HBM, 1000 V CDM - meets industrial reliability requirements without additional protection circuitry. |
| Power-up State | All I/Os as inputs, all interrupts masked - prevents glitching and ensures clean system initialization. |
Pinout & Package
HVQFN16 package (3 mm × 3 mm × 0.85 mm body, exposed thermal pad); RoHS-compliant, leadless quad flat no-lead construction with 16 terminals. Exposed pad must be soldered to PCB thermal pad with vias for optimal thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Hardware I²C address bit 0 | Configures LSB of fixed slave address (0x20–0x27 for PCAL9554C); enables up to eight devices on same bus. |
| A1 | Hardware I²C address bit 1 | Second address select bit; combined with A0/A2, defines unique I²C address within PCAL9554C family. |
| A2 | Hardware I²C address bit 2 | MSB of hardware address; PCAL9554CBS,128 uses base address 0x20 (0111xxxx for PCAL9554C variant). |
| P0–P7 | Bi-directional I/O ports | Programmable as input or output; support latch, polarity inversion, pull-up/down enable/selection, and drive strength control. |
| INT | Open-drain interrupt output | Active-low signal asserted when unmasked input state differs from Input Port register; cleared only by reading Input Port register. |
| SCL | I²C serial clock input | Accepts standard I²C timing; Schmitt-triggered for noise immunity and compatibility with slow clock edges. |
| SDA | I²C serial data bidirectional line | Open-drain structure compatible with I²C bus topology; supports multi-master arbitration. |
| VDD | Positive supply voltage | 1.65–5.5 V operation; powers internal logic and I/O buffers; 5 V tolerant on all I/O pins regardless of VDD level. |
| VSS | Ground reference | Must connect both pin 6 and exposed thermal pad to system ground for functional and thermal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Agile I/O register set | Eight extended registers (40h–4Fh) enable per-pin configuration of drive strength, latch, pull-up/down, mask, and output mode - eliminating need for external logic or firmware workarounds. |
| Latchable inputs | Input state changes are captured and held until Input Port register read - prevents missed interrupts during I²C polling latency. |
| Programmable pull-up/down | 100 kΩ resistors (±50 %) individually enabled/disabled and selected as pull-up or pull-down - replaces external discrete resistors and saves board space. |
| Maskable interrupt | Per-pin interrupt enable/disable via Interrupt Mask register (45h); default power-up mask prevents spurious interrupts during boot. |
| Output drive strength control | Four levels (25 %–100 %) per I/O reduce rise/fall times in low-capacitance applications and minimize EMI without sacrificing drive capability. |
Applications
| ACPI Power Switch Interface | LED Status Indication |
|---|---|
Use Scenario: Monitoring mechanical power buttons or lid switches in laptops and embedded systems requiring OS-level power state transitions. IC Role / Device Role / Timing Role: GPIO expander providing debounced, interrupt-driven input sensing with hardware addressability for multi-switch configurations. Use Value: Eliminates microcontroller GPIO resource contention; INT signal wakes host CPU only on valid edge events, reducing polling overhead and power consumption. |
Use Scenario: Driving status LEDs for system health, connectivity, or user feedback in industrial HMIs and network equipment. IC Role / Device Role / Timing Role: Direct-sink driver for up to eight LEDs with programmable current drive and polarity inversion for common-anode/cathode flexibility. Use Value: 25 mA per I/O enables direct LED drive without external transistors; programmable drive strength optimizes brightness and EMI in compact layouts. |
| Fan Speed Control Interface | Sensor Signal Conditioning Hub |
Use Scenario: Reading tachometer outputs and controlling PWM fan enable lines in thermal management subsystems. IC Role / Device Role / Timing Role: Bidirectional I/O hub converting analog tach pulses to digital counts and asserting fan enable signals under firmware control. Use Value: Latchable inputs capture fast tach edges reliably; open-drain outputs interface cleanly with fan controller logic-level requirements. |
Use Scenario: Aggregating digital outputs from temperature, humidity, and motion sensors in smart building nodes. IC Role / Device Role / Timing Role: Level-shifting and interrupt-aggregating interface between 5 V sensors and 3.3 V microcontrollers. Use Value: 5 V-tolerant I/Os accept sensor logic levels directly; programmable pull-ups eliminate external biasing; INT pin signals any sensor event to host MCU. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C GPIO expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9554CPW,118 | Lacks Agile I/O features: no programmable drive strength, input latch, pull-up/down selection, or interrupt status register; fixed weak pull-ups only. | Suitable for basic I/O expansion where interrupt masking and latch behavior are not required; lower software complexity but less flexible I/O control. | Select PCA9554CPW,118 only if cost sensitivity outweighs need for per-pin configurability and deterministic interrupt handling. |
| TCA6408APWR | TI part with identical 8-bit I²C GPIO, 1.65–5.5 V range, and open-drain INT, but no input latch or programmable pull-up/down; interrupt mask is register-based but lacks status register. | Compatible for simple input monitoring or LED driving where input edge capture persistence isn't needed; different register map requires firmware adaptation. | Choose TCA6408APWR when sourcing diversity is prioritized and Agile I/O features are non-critical to system timing or reliability requirements. |
Compared with PCA9554CPW,118 and TCA6408APWR, the PCAL9554CBS,128 provides uniquely deterministic interrupt handling via latch + status register, per-pin drive strength tuning for EMI control, and full software-configurable pull-up/down - making it essential for systems demanding robust, low-latency I/O event response without firmware polling overhead.
Availability
PCAL9554CBS,128 is available at Aetrix Electronics and suitable for industrial automation interfaces, embedded sensor hubs, and consumer electronics power management systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCAL9554CBS,128 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in I²C peripheral IP and low-power interface design.
The PCAL9554CBS,128 belongs to NXP's Agile I/O GPIO expander product line, engineered specifically for systems needing intelligent, interrupt-driven I/O expansion with minimal firmware overhead and maximum hardware configurability across mixed-voltage platforms.
FAQ
What is the I²C slave address of PCAL9554CBS,128?
The PCAL9554CBS,128 is the PCAL9554C variant and uses a base I²C address of 0x20 (0b0100000). Hardware address pins A2, A1, and A0 allow selection of eight addresses from 0x20 to 0x27. This differs from the PCAL9554B variant (base 0x20 vs. 0x38), enabling up to 16 identical devices on one bus without conflict. The R/W bit is appended during transmission.
Does PCAL9554CBS,128 support 5 V tolerant I/Os when VDD = 3.3 V?
Yes, PCAL9554CBS,128 supports 5 V tolerant I/Os regardless of VDD level - meaning P0–P7 can safely accept input voltages up to 5.5 V even when powered from 1.65 V to 3.3 V. This eliminates level shifters when interfacing with 5 V sensors or switches while operating from low-voltage rails, preserving signal integrity and simplifying BOM.
How does the interrupt (INT) pin of PCAL9554CBS,128 get cleared?
The INT pin of PCAL9554CBS,128 is cleared only by reading the Input Port register (address 0x00) - not by writing to any register or toggling I/O states. If input latching is enabled, INT remains asserted until the Input Port register is read, ensuring no edge events are missed during I²C transaction latency. This behavior is confirmed in Section 6.7 and Figure 10 of the official datasheet.
Can PCAL9554CBS,128 drive LEDs directly?
Yes, PCAL9554CBS,128 can drive LEDs directly with up to 25 mA sink current per I/O pin. Its outputs support push-pull or open-drain modes, and drive strength is programmable in four levels (25 %–100 %) to optimize brightness and EMI. No external transistor or current-limiting resistor is required when VDD matches LED forward voltage and current targets align with selected drive strength.
What is the power-up default configuration of PCAL9554CBS,128?
At power-up, PCAL9554CBS,128 initializes all 8 I/Os as high-impedance inputs (Configuration register = 0xFF), enables pull-up resistors on all pins (Pull-up/Down Enable = 0xFF), masks all interrupts (Interrupt Mask register = 0xFF), and sets all outputs to high (Output Port register = 0xFF). This ensures glitch-free startup and prevents unintended I/O activity before firmware initialization.
PCAL9554CBS,128 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- Agile
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- I2C, SMBus
- Interrupt Output:
- Yes
- Features:
- POR
- Output Type:
- Open Drain, Push-Pull
- Current - Output Source/Sink:
- 10mA, 25mA
- Clock Frequency:
- 400 kHz
- Voltage - Supply:
- 1.65V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HVQFN (3x3)
PCAL9554CBS,128 FAQ
1.How can I place an order for PCAL9554CBS,128 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCAL9554CBS,128 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PCAL9554CBS,128 reliable?
The price and inventory of PCAL9554CBS,128 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCAL9554CBS,128 is usually 5 days.
3.What payment methods are accepted for PCAL9554CBS,128?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCAL9554CBS,128 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCAL9554CBS,128?
PCAL9554CBS,128 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCAL9554CBS,128 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PCAL9554CBS,128?
For technical support, including PCAL9554CBS,128 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCAL9554CBS,128 requirements.
6.How does Aetrix verify that PCAL9554CBS,128 is sourced from the original manufacturer or authorized distributors?
All PCAL9554CBS,128 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PCAL9554CBS,128 meets industry standards.
7.What is the process for return or replacement of PCAL9554CBS,128?
All PCAL9554CBS,128 units undergo pre-shipment inspection (PSI). If there is an issue with PCAL9554CBS,128, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PCAL9554CBS,128 part is unused and in its original packaging.
Return procedure for PCAL9554CBS,128:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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