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NXP Semiconductors PCA9538BS,118
- Part No.:
- PCA9538BS,118
- Manufacturer:
- NXP Semiconductors
- Category:
- I/O Expanders
- Package:
- 16-VQFN Exposed Pad
- Datasheet:
-
PCA9538BS,118.pdf
- Description:
- IC XPND 400KHZ I2C SMBUS 16HVQFN
- Quantity:
- Payment:
- Shipping:
Inventory:10,278
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Product details
Overview
PCA9538BS,118 from NXP Semiconductors is an 8-bit I²C-bus/SMBus GPIO expander with interrupt and active-low reset, housed in a 4×4 mm HVQFN16 package. It provides configurable input/output pins, polarity inversion, and low-power standby current (≤1 μA) for embedded control applications requiring remote I/O expansion. Its 5 V-tolerant I/Os, 2.3–5.5 V supply range, and 0–400 kHz clock support enable use in mixed-voltage sensor interfaces and industrial control subsystems.
For engineers reviewing the PCA9538BS,118 datasheet, PCA9538BS,118 pinout, PCA9538BS,118 application, or PCA9538BS,118 equivalent, this device delivers deterministic I/O state management via four dedicated configuration registers (Input/Output/Polarity/Configuration), open-drain interrupt signaling, hardware address selection (A0/A1), and internal power-on reset-critical for reliable system initialization and event-driven monitoring in resource-constrained designs.
Technical Context
The PCA9538BS,118 implements a register-mapped I²C slave interface with four 8-bit registers: Input Port (read-only), Output Port (read/write), Polarity Inversion (read/write), and Configuration (read/write). Each I/O defaults to high-impedance input at power-on reset, and direction is set per-pin via the Configuration register.
Its interrupt output (INT) activates when any configured input pin transitions and differs from its latched Input Port value; reading the Input Port register clears the interrupt. The active-low RESET pin triggers full register and state-machine initialization without cycling VDD, supporting in-system recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 2.3 V to 5.5 V - supports direct interfacing with 3.3 V and 5 V microcontrollers without level shifters. |
| I/O count & type | 8 bidirectional CMOS I/Os - each independently configurable as input or output; 5 V tolerant even when VDD = 2.3 V. |
| Interrupt logic | Open-drain, active-low INT - pulls low when input state changes; requires external pull-up; cleared by reading Input Port register. |
| Reset input | Active-low RESET pin - initiates full register reset and state-machine reinitialization; requires external pull-up if unused. |
| I²C speed | 0 Hz to 400 kHz - compatible with standard-mode and fast-mode I²C buses; includes noise filtering on SCL/SDA inputs. |
| Standby current | ≤1 μA at VDD = 5.5 V, VI = VSS or VDD - enables ultra-low-power operation in battery-backed or energy-harvesting systems. |
| Operating temperature | −40 °C to +85 °C - qualified for industrial ambient environments without derating. |
Pinout & Package
HVQFN16 package (SOT629-1), 4 × 4 × 0.85 mm body, thermally enhanced with exposed center pad soldered to PCB ground plane for improved thermal dissipation and electrical stability.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Hardware address bit 0 | Configures LSB of I²C address (1110000x); tied HIGH/LOW to select one of two addresses per A1 state. |
| A1 | Hardware address bit 1 | Configures MSB of I²C address (11100xx0); enables up to four PCA9538 devices on same bus. |
| RESET | Active-low asynchronous reset | Forces all registers to default values and restarts SMBus/I²C state machine; requires external pull-up resistor. |
| IO0–IO7 | Bidirectional I/O terminals | Each configurable as input (high-Z) or output (push-pull); polarity invertible per-pin via Polarity register. |
| INT | Open-drain interrupt output | Asserts LOW when input state change occurs; shared across all 8 I/Os; cleared by reading Input Port register. |
| SCL / SDA | I²C serial clock/data lines | Compliant with I²C-bus and SMBus protocols; include integrated noise filters for robust operation in noisy environments. |
| VDD / VSS | Power supply and ground | VDD accepts 2.3–5.5 V; VSS connects to PCB ground; exposed pad must be soldered to ground for thermal/electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Register-based I/O control | Four dedicated 8-bit registers (Input/Output/Polarity/Configuration) enable precise, software-defined I/O behavior without external logic. |
| Polarity inversion per I/O | Individual bit control in Polarity Inversion register flips logical sense of input data-simplifies firmware handling of active-HIGH vs. active-LOW sensors. |
| No-glitch power-up | Internal power-on reset ensures all registers initialize to known states (I/Os = inputs, outputs = HIGH) before first I²C access-prevents spurious outputs. |
| 5 V-tolerant I/Os | I/O pins accept up to 5.5 V regardless of VDD (down to 2.3 V), enabling direct connection to 5 V peripherals without level-shifting circuitry. |
| Low EMI SCL/SDA filtering | Integrated input filters suppress spikes ≤50 ns-reducing susceptibility to board-level noise in industrial or motor-drive adjacent layouts. |
Applications
| Industrial Sensor Interface | LED Status Panel Control |
|---|---|
|
Use Scenario: Monitoring temperature, humidity, and door-switch status in programmable logic controller (PLC) backplane modules. IC Role / Device Role / Timing Role: PCA9538BS,118 acts as remote I/O node, converting discrete sensor signals into I²C-accessible register values with interrupt-driven edge detection. Use Value: Reduces host MCU GPIO usage by 8 pins; enables wake-on-event capability via INT line; eliminates need for discrete buffers or level shifters due to 5 V tolerance. |
Use Scenario: Driving 8-channel LED indicators on a network switch front panel with brightness-independent on/off control. IC Role / Device Role / Timing Role: PCA9538BS,118 serves as constant-current sink driver (with external resistors), configured as 8 outputs with polarity inversion for active-LOW LED logic. Use Value: Achieves <1 μA standby current when LEDs are off; supports mixed 3.3 V host and 5 V LED supply rails; simplifies BOM by removing 8 discrete transistors. |
| Pushbutton & Fan Control Hub | Alarm System Peripheral Expansion |
|
Use Scenario: Managing pushbutton debouncing, fan tachometer inputs, and PWM fan speed control signals in HVAC control boards. IC Role / Device Role / Timing Role: PCA9538BS,118 aggregates mechanical button states (inputs) and drives fan enable lines (outputs), using INT to notify host of button press events. Use Value: Eliminates software polling overhead; provides hardware-synchronized edge capture; withstands 5 V fan supply while operating from 3.3 V MCU rail. |
Use Scenario: Expanding zone inputs (door/window sensors) and alarm output drivers in residential security panels with limited main processor GPIO. IC Role / Device Role / Timing Role: PCA9538BS,118 functions as isolated I/O extender, isolating alarm circuitry from main controller via I²C, with RESET enabling field-recoverable fault clearing. Use Value: Enables hot-swappable sensor zones; supports fail-safe reset without power cycle; meets industrial ESD requirements (2000 V HBM). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar GPIO expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA6408A | Lacks dedicated RESET pin; uses software reset only; no polarity inversion register. | Requires host firmware intervention for full reset; less suitable for systems needing hardware-initiated recovery. | Choose TCA6408A only if RESET functionality is managed externally and polarity inversion is unnecessary. |
| PCA9554BS | Includes internal 100 kΩ I/O pull-up resistors; higher standby current (~2.5 μA); identical pinout and register map. | Reduces external component count for weak pull-ups but increases quiescent power; not drop-in due to different power profile. | Prefer PCA9554BS where board space is constrained and pull-ups are needed, but avoid in ultra-low-power designs. |
Compared with TCA6408A and PCA9554BS, the PCA9538BS,118 uniquely combines hardware RESET, polarity inversion, and sub-1 μA standby current in HVQFN16-making it optimal for industrial edge nodes requiring deterministic recovery and minimal energy leakage.
Availability
PCA9538BS,118 is available at Aetrix Electronics and suitable for industrial automation, building control systems, and embedded instrumentation requiring stable component supply, extended temperature operation, and long-term manufacturing continuity.
Supply support for PCA9538BS,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, with deep expertise in interface and power management ICs.
The PCA9538BS,118 belongs to NXP's I²C-bus I/O expander product line, designed specifically to simplify GPIO expansion in space-constrained, low-power embedded systems where interrupt-driven event handling and hardware reset reliability are critical.
FAQ
What is the maximum I²C clock frequency supported by PCA9538BS,118?
The PCA9538BS,118 supports I²C-bus operation up to 400 kHz (fast-mode), compliant with both I²C-bus and SMBus specifications. Its internal noise filters on SCL and SDA ensure robust timing margin at this rate, and the device maintains full register functionality without degradation across the entire 0–400 kHz range.
Does PCA9538BS,118 require external pull-up resistors on SCL and SDA lines?
Yes, PCA9538BS,118 requires external pull-up resistors on both SCL and SDA lines to establish valid logic HIGH levels, as it uses open-drain I²C interface architecture. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and speed; NXP recommends 4.7 kΩ for standard-mode operation.
How does the RESET pin function on PCA9538BS,118, and what external components are needed?
The RESET pin on PCA9538BS,118 is active-low and asynchronously initializes all internal registers and the I²C state machine. It requires an external pull-up resistor to VDD (typically 10 kΩ) if not actively driven; the minimum pulse width is 4 ns, and the device releases reset after the pin returns HIGH.
Can PCA9538BS,118 drive LEDs directly, and what current limits apply?
PCA9538BS,118 can sink up to 24 mA per I/O pin (at VDD = 4.5 V, VOL = 0.7 V) and source up to 85 mA total across all outputs. For LED driving, configure I/Os as outputs and connect LEDs between VDD and the pin (common-anode); always limit current with series resistors and observe per-pin and total current limits specified in the datasheet.
What is the purpose of the Polarity Inversion register in PCA9538BS,118?
The Polarity Inversion register in PCA9538BS,118 allows individual inversion of input logic levels read from the Input Port register. When a bit is set to '1', the corresponding input bit is logically complemented-enabling seamless integration with both active-HIGH and active-LOW sensors without modifying host firmware logic.
PCA9538BS,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-VQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- I2C, SMBus
- Interrupt Output:
- Yes
- Features:
- POR
- Output Type:
- Push-Pull
- Current - Output Source/Sink:
- 10mA, 25mA
- Clock Frequency:
- 400 kHz
- Voltage - Supply:
- 2.3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HVQFN (4x4)
PCA9538BS,118 FAQ
1.How can I place an order for PCA9538BS,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9538BS,118 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 PCA9538BS,118 reliable?
The price and inventory of PCA9538BS,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9538BS,118 is usually 5 days.
3.What payment methods are accepted for PCA9538BS,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9538BS,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9538BS,118?
PCA9538BS,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9538BS,118 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 PCA9538BS,118?
For technical support, including PCA9538BS,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9538BS,118 requirements.
6.How does Aetrix verify that PCA9538BS,118 is sourced from the original manufacturer or authorized distributors?
All PCA9538BS,118 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 PCA9538BS,118 meets industry standards.
7.What is the process for return or replacement of PCA9538BS,118?
All PCA9538BS,118 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9538BS,118, 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 PCA9538BS,118 part is unused and in its original packaging.
Return procedure for PCA9538BS,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCA9538BS,118 Tags
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