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NXP Semiconductors PCA8574AD,512
- Part No.:
- PCA8574AD,512
- Manufacturer:
- NXP Semiconductors
- Category:
- I/O Expanders
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
PCA8574AD,512.pdf
- Description:
- IC XPNDR 400KHZ I2C 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,193
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Product details
Overview
PCA8574AD,512 from NXP Semiconductors is an 8-bit quasi-bidirectional I²C-bus I/O expander with active-low open-drain interrupt output, 400 kHz Fast-mode I²C interface, 2.3 V to 5.5 V operation, and 25 mA per-pin sink capability for direct LED drive. It operates from −40 °C to +85 °C and supports up to eight devices on one bus via A0–A2 address pins.
For engineers reviewing the PCA8574AD,512 datasheet, PCA8574AD,512 pinout, PCA8574AD,512 application, or PCA8574AD,512 equivalent, this device serves as a low-power remote GPIO solution for embedded systems requiring interrupt-driven input monitoring and high-current LED control without external drivers.
Technical Context
The PCA8574AD,512 implements a single-register quasi-bidirectional I/O architecture: each of P0–P7 functions as input or output without direction register, initialized at power-on as inputs with 100 µA weak pull-up to VDD. Its internal Power-On Reset (POR) ensures deterministic startup state.
It uses Fast-mode I²C (400 kHz) with fixed 7-bit slave address 0x70–0x77 (PCA8574A family), supports open-drain INT assertion on any I/O state change, and delivers 200 mA total package sink current - enabling multi-pin parallel sinking for higher-load applications like LED arrays.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Speed | 400 kHz Fast-mode - enables faster polling and reduced bus occupancy vs. standard 100 kHz I²C expanders. |
| Supply Voltage | 2.3 V to 5.5 V - compatible with 3.3 V and 5 V logic domains; I/Os tolerate 5.5 V when VDD ≤ 5.5 V. |
| Quasi-bidirectional I/Os | 8 pins (P0–P7), no direction register - simplifies firmware, reduces memory footprint, and eliminates direction-control timing constraints. |
| Sink Current | 25 mA per pin (min), 200 mA total package - drives LEDs directly without external transistors or current-limiting resistors on the high side. |
| Interrupt Output | Active-low open-drain INT - signals microcontroller on any input transition, eliminating continuous I²C polling and reducing system power. |
| Standby Current | 4.5 µA typical - suitable for battery-powered mobile and portable equipment where quiescent power is critical. |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial and extended-temperature embedded applications. |
Pinout & Package
PCA8574AD,512 is supplied in TSSOP16 package (SOT403-1), 4.4 mm body width, 16-lead plastic thin shrink small outline package.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Hardware address input 0 | Selects LSB of 7-bit slave address (0x70–0x77); must be externally biased HIGH/LOW - no internal pull-up/pull-down. |
| A1 | Hardware address input 1 | Second bit of address selection; enables up to eight PCA8574AD,512 devices on same I²C bus without conflict. |
| A2 | Hardware address input 2 | MSB of address selection; combined with A0/A1, defines unique I²C address within PCA8574A family range. |
| P0–P7 | Quasi-bidirectional I/O port | Each pin defaults to input at power-on with 100 µA weak pull-up; writes '0' enable strong sink (25 mA), writes '1' enable weak pull-up or input read. |
| INT | Interrupt output | Active-low open-drain signal asserted when any P0–P7 input state differs from its register value - triggers MCU ISR without polling. |
| SCL | I²C serial clock input | Accepts 400 kHz clock; synchronized with SDA for data transfer; requires external pull-up resistor. |
| SDA | I²C serial data bidirectional | Open-drain line shared across I²C bus; requires external pull-up; carries address, command, and data bytes. |
| VDD | Positive supply | 2.3 V to 5.5 V input; powers internal logic, I/O drivers, and weak pull-ups; decoupling capacitor recommended. |
| VSS | Ground reference | 0 V return path for all internal circuits and I/O sinks; must be low-impedance connection to system ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Single-register I/O control | Eliminates direction register overhead - firmware reads/writes one byte to configure all 8 pins as input or output simultaneously. |
| Power-on reset initialization | Guarantees all P0–P7 start as inputs with 100 µA pull-up - prevents floating states and ensures safe startup in unconfigured systems. |
| 25 mA per-pin sink drive | Directly drives standard LEDs without external MOSFETs or driver ICs - reduces BOM count and PCB area in indicator-heavy designs. |
| Eight hardware-selectable addresses | Enables up to 16 I/O expanders (8 PCA8574 + 8 PCA8574A) on one I²C bus - scales to 128 GPIOs with minimal bus resource usage. |
| ESD & latch-up robustness | 2000 V HBM / 1000 V CDM ESD rating and >100 mA latch-up immunity - improves reliability in handling-sensitive industrial and medical environments. |
Applications
| LED Signage Control | Industrial Keypad Interface |
|---|---|
Use Scenario: Driving 8-segment alphanumeric displays and status indicators in outdoor signage cabinets. IC Role / Device Role / Timing Role: Remote I/O expander providing sink-driven LED column control and row scanning coordination via I²C. Use Value: 25 mA per-pin sink capability eliminates discrete transistor arrays; INT pin notifies MCU only when button press occurs - cutting background polling overhead by >95%. |
Use Scenario: Scanning mechanical keypads in PLC operator panels with EMI-prone wiring runs. IC Role / Device Role / Timing Role: Input monitor with interrupt-triggered read - detects key closures asynchronously without bus contention. Use Value: Quasi-bidirectional ports tolerate contact bounce and long traces; 100 µA weak pull-up prevents false triggers while enabling low-power wake-up from deep sleep. |
| Medical Device Status Panel | Server Rack Management Module |
Use Scenario: Monitoring door interlocks, sensor faults, and power-good signals in diagnostic imaging equipment. IC Role / Device Role / Timing Role: Fault-monitoring I/O hub that asserts INT on safety-critical state changes for immediate MCU response. Use Value: −40 °C to +85 °C rating ensures operation inside sealed enclosures; 4.5 µA standby current extends battery backup runtime during AC loss. |
Use Scenario: Controlling fan speed indicators, hot-swap status LEDs, and presence detection on server backplanes. IC Role / Device Role / Timing Role: Distributed GPIO node managing local indicators and reporting via shared I²C bus to baseboard management controller (BMC). Use Value: TSSOP16 package fits dense server PCB layouts; 200 mA total sink supports multi-LED clusters per device - reducing component count per slot. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C I/O expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA8574D,512 | Same functionality but PCA8574 (not PCA8574A) family - fixed I²C address range 0x40–0x47 instead of 0x70–0x77. | Used where legacy PCF8574T/3 compatibility is required; shares identical pinout and electrical specs. | Select PCA8574D,512 only if bus address space conflicts with existing PCA8574A devices or migration from PCF8574 is needed. |
| PCA9674APW,118 | Successor with 1 MHz Fm+ I²C, 64 selectable addresses, same 25 mA sink, but adds glitch filtering and improved noise immunity. | Preferred for new designs requiring higher bandwidth, more nodes per bus, or enhanced EMI resilience in noisy server/industrial settings. | Choose PCA9674APW,118 for future-proofing and scalability; PCA8574AD,512 remains optimal for cost-sensitive, pin-compatible replacements. |
Compared with PCA8574D,512, PCA8574AD,512 provides non-overlapping I²C addresses enabling coexistence on the same bus; versus PCA9674APW,118, it offers proven stability and lower cost but lacks higher-speed I²C and advanced filtering - making it ideal for established designs prioritizing drop-in compatibility and BOM continuity.
Availability
PCA8574AD,512 is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, and server management applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCA8574AD,512 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 company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.
The PCA8574/74A product line was designed to extend microcontroller GPIO resources over I²C with minimal firmware overhead, targeting cost-sensitive embedded systems needing reliable remote I/O and interrupt-driven event handling.
FAQ
What is the I²C slave address range for PCA8574AD,512?
The PCA8574AD,512 belongs to the PCA8574A family and uses a fixed 7-bit base address of 0x70. With hardware address pins A2–A0, it supports eight possible addresses: 0x70 through 0x77 (hexadecimal). This range is distinct from the PCA8574 family (0x40–0x47), allowing both families to coexist on the same I²C bus without conflict. The PCA8574AD,512 datasheet confirms this mapping in Table 5.
Can PCA8574AD,512 drive LEDs directly without external components?
Yes, PCA8574AD,512 can drive standard LEDs directly using its quasi-bidirectional outputs. Each pin (P0–P7) provides a minimum 25 mA sink current at VDD = 4.5 V, sufficient for common 20 mA LEDs. A series current-limiting resistor is still required on the LED anode side (connected to VDD), but no external transistor or driver IC is needed - simplifying layout and reducing BOM cost.
How does the interrupt (INT) pin behave on PCA8574AD,512?
The INT pin on PCA8574AD,512 is an active-low open-drain output that asserts (goes LOW) whenever the state of any input pin (P0–P7) differs from its corresponding bit in the input port register. It resets to HIGH after the master reads the port register or writes any value to it. This edge-triggered behavior eliminates polling and enables efficient event-driven firmware architectures.
What is the power-on behavior of PCA8574AD,512 I/O pins?
At power-on, PCA8574AD,512 initializes all eight I/O pins (P0–P7) as inputs with a 100 µA weak internal pull-up to VDD. This is enforced by the internal Power-On Reset (POR) circuit, ensuring a known, safe state before firmware intervention. No external pull-up resistors are required for basic input operation, though stronger pull-ups may be added for noise immunity in electrically noisy environments.
Is PCA8574AD,512 pin-compatible with PCF8574AT/3?
Yes, PCA8574AD,512 is explicitly documented as a drop-in replacement for PCF8574AT/3 per NXP's ordering information table. It shares identical TSSOP16 pinout, electrical specifications, and functional behavior - including I²C address scheme, interrupt logic, and quasi-bidirectional I/O operation - enabling seamless migration without PCB redesign.
PCA8574AD,512 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- I2C
- Interrupt Output:
- Yes
- Features:
- POR
- Output Type:
- Push-Pull
- Current - Output Source/Sink:
- 100µA, 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-SO
PCA8574AD,512 FAQ
1.How can I place an order for PCA8574AD,512 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA8574AD,512 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 PCA8574AD,512 reliable?
The price and inventory of PCA8574AD,512 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA8574AD,512 is usually 5 days.
3.What payment methods are accepted for PCA8574AD,512?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA8574AD,512 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA8574AD,512?
PCA8574AD,512 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA8574AD,512 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 PCA8574AD,512?
For technical support, including PCA8574AD,512 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA8574AD,512 requirements.
6.How does Aetrix verify that PCA8574AD,512 is sourced from the original manufacturer or authorized distributors?
All PCA8574AD,512 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 PCA8574AD,512 meets industry standards.
7.What is the process for return or replacement of PCA8574AD,512?
All PCA8574AD,512 units undergo pre-shipment inspection (PSI). If there is an issue with PCA8574AD,512, 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 PCA8574AD,512 part is unused and in its original packaging.
Return procedure for PCA8574AD,512:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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