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NXP Semiconductors PCA8574AN,112
- Part No.:
- PCA8574AN,112
- Manufacturer:
- NXP Semiconductors
- Category:
- I/O Expanders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
PCA8574AN,112.pdf
- Description:
- IC XPNDR 400KHZ I2C 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,644
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Product details
Overview
PCA8574AN,112 from NXP Semiconductors is an 8-bit quasi-bidirectional I/O expander for I²C-bus (SCL/SDA), operating from 2.3 V to 5.5 V with 400 kHz Fast-mode support. It features eight latched I/O ports (P0–P7), active-low open-drain interrupt (INT), three hardware address pins (A0–A2), and 25 mA per-pin sink capability - enabling direct LED drive in embedded control and keypad monitoring applications.
For engineers reviewing the PCA8574AN,112 datasheet, PCA8574AN,112 pinout, PCA8574AN,112 application, or PCA8574AN,112 equivalent, this device delivers low-power remote I/O expansion with interrupt-driven change detection, eliminating continuous I²C polling in resource-constrained microcontroller systems.
Technical Context
The PCA8574AN,112 implements a single-register quasi-bidirectional I/O architecture: each port defaults to input at power-on with a 100 µA weak pull-up, and transitions to output when written LOW (strong sink) or HIGH (accelerated pull-up during ACK cycle). No direction register is required, simplifying firmware and reducing command overhead.
Its interrupt logic asserts INT (active LOW) on any input state change relative to the input port register, and resets automatically upon read/write access or return to prior state - enabling efficient event-driven host interaction without external debouncing or polling loops.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Bus Speed | 400 kHz Fast-mode - supports higher throughput than legacy 100 kHz PCF8574, reducing bus occupancy in multi-device systems. |
| Supply Voltage Range | 2.3 V to 5.5 V - compatible with 3.3 V and 5 V logic domains; I/Os tolerate up to 5.5 V regardless of VDD. |
| Quasi-bidirectional I/Os | 8 pins (P0–P7), each configurable as input or output without direction register - simplifies firmware and enables mixed-mode operation per pin. |
| Sink Current per Pin | 25 mA minimum at 4.5 V - sufficient to drive standard LEDs directly without external transistors. |
| Total Package Sink Limit | 200 mA - allows parallel sinking across multiple pins for higher-current loads (e.g., LED arrays). |
| Interrupt Output | Active LOW open-drain INT - connects directly to MCU interrupt input with external pull-up; asserts on any input state transition. |
| Standby Current | 4.5 µA typical - enables battery-powered operation in mobile and portable equipment. |
Pinout & Package
PCA8574AN,112 is supplied in SO16 (plastic small outline, 16-lead, 7.5 mm body width) per ordering code PCA8574AN,112 - identical pinout to PCA8574D/PCA8574AD variants.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 A0 | Hardware slave address bit 0 | Externally tied HIGH/LOW to select one of eight I²C addresses (0x40–0x47 for PCA8574 family). |
| 2 A1 | Hardware slave address bit 1 | Combined with A0/A2, enables up to eight PCA8574AN,112 devices on same I²C bus without address conflict. |
| 3 A2 | Hardware slave address bit 2 | No internal pull-ups - must be externally biased to define unique slave address in multi-device configurations. |
| 4 P0 | Quasi-bidirectional I/O port 0 | Default input at power-on; sinks 25 mA when driven LOW; weak 100 µA pull-up when HIGH. |
| 5 P1 | Quasi-bidirectional I/O port 1 | Independent of other ports; usable as keypad input or LED output without reconfiguration. |
| 6 P2 | Quasi-bidirectional I/O port 2 | Same electrical behavior as P0/P1 - no direction register needed for mixed input/output use. |
| 7 P3 | Quasi-bidirectional I/O port 3 | Supports both sensing (e.g., switch closure) and actuation (e.g., relay driver) in same device. |
| 8 VSS | Ground reference | Primary supply return; must be low-impedance connection to avoid noise coupling into I/O states. |
| 9 P4 | Quasi-bidirectional I/O port 4 | Retains state across I²C transactions; latch holds output until next write, enabling stable peripheral control. |
| 10 P5 | Quasi-bidirectional I/O port 5 | Compatible with 5 V-tolerant inputs even when VDD = 3.3 V - simplifies level-shifting in mixed-voltage systems. |
| 11 P6 | Quasi-bidirectional I/O port 6 | Interrupt-triggered reads reflect actual pin voltage, not just register value - critical for robust input monitoring. |
| 12 P7 | Quasi-bidirectional I/O port 7 | Capable of driving indicator LEDs directly; current-limited by internal structure to prevent damage. |
| 13 INT | Interrupt output | Open-drain, active LOW - requires external pull-up; asserts when any input differs from its register copy. |
| 14 SCL | I²C serial clock input | Accepts 400 kHz clock; synchronized internally to sample SDA and generate ACK/NACK. |
| 15 SDA | I²C serial data bidirectional | Open-drain interface; requires external pull-up; supports multi-master arbitration and clock stretching. |
| 16 VDD | Positive supply | Power source for logic and I/O; internal POR circuit initializes all ports as inputs upon VDD ramp. |
Key Features
| Feature | Design Value |
|---|---|
| Single-register I/O control | Eliminates need for direction register writes - reduces I²C traffic and firmware complexity in real-time systems. |
| Hardware address selection | Three pins (A0–A2) enable eight unique I²C addresses per device type, supporting up to 16 expanders (128 I/Os) on one bus. |
| Power-on reset initialization | Internal POR sets all I/Os as inputs with 100 µA weak pull-up - ensures safe default state before firmware initialization. |
| Interrupt-driven input monitoring | INT pin eliminates polling overhead; notifies MCU only when input state changes - conserves CPU cycles and power. |
| 5.5 V-tolerant I/Os | Allows direct interfacing with 5 V peripherals while operating from 3.3 V supply - avoids external level shifters in mixed-voltage designs. |
Applications
| LED Signage Control | Industrial Keypad Interface |
|---|---|
Use Scenario: Driving 8-segment displays and status indicators in industrial HMIs where MCU GPIOs are constrained. IC Role / Device Role / Timing Role: Remote I/O expander providing parallel output control via I²C, with latched outputs ensuring stable LED states between updates. Use Value: Reduces MCU pin count requirement by 8; 25 mA sink per pin drives LEDs directly without external drivers, lowering BOM cost and board area. |
Use Scenario: Scanning mechanical keypads in PLCs or medical devices requiring ESD-hardened, low-leakage input monitoring. IC Role / Device Role / Timing Role: Quasi-bidirectional port configured as input with weak pull-up, detecting key closures via interrupt-driven edge detection. Use Value: INT signal triggers MCU only on keypress - eliminates continuous polling, saving ~30% CPU time in idle state and extending battery life. |
| Server Fan Monitoring | Mobile Device Status Indication |
Use Scenario: Reading tachometer signals and fault flags from multiple cooling fans in rack-mounted servers. IC Role / Device Role / Timing Role: Input monitor capturing fan RPM pulses and over-temperature alerts via P0–P7, with interrupt signaling on fault conditions. Use Value: Single PCA8574AN,112 replaces discrete optocouplers and level shifters; 2.3 V min supply supports low-power server standby modes. |
Use Scenario: Controlling backlight brightness and notification LEDs in cellular handsets with tight power budgets. IC Role / Device Role / Timing Role: Output driver for RGB LEDs and vibration motor control, leveraging 4.5 µA standby current and 5.5 V tolerance. Use Value: Enables always-on status indication with <5 µA system quiescent current; 200 mA total sink supports multi-LED concurrent activation. |
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 |
|---|---|---|---|
| PCA8574PW,112 | TSSOP16 package (4.4 mm width) vs. SO16 (7.5 mm); identical electrical specs and pinout. | Better suited for space-constrained PCBs; thermal resistance higher (160 °C/W vs. 115 °C/W), limiting max ambient in high-power-density layouts. | Select PCA8574PW,112 when board area is critical and thermal margin permits. |
| PCA9674APW,118 | 1 MHz Fm+ I²C, 64 selectable addresses, same 25 mA sink, but no interrupt output (replaced by hardware reset input). | Requires software polling or external interrupt logic; better for high-speed, high-node-count systems where interrupt line is unavailable or redundant. | Choose PCA9674APW,118 when upgrading bus speed and node count outweighs loss of hardware interrupt functionality. |
Compared with PCA8574PW,112, the PCA8574AN,112 offers lower thermal resistance and larger pad spacing for easier soldering; versus PCA9674APW,118, it retains interrupt-driven efficiency at the cost of slower bus speed and fewer address options - making it optimal for cost-sensitive, interrupt-reliant industrial controls.
Availability
PCA8574AN,112 is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, and LED signage applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCA8574AN,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 broad analog, digital, and mixed-signal product portfolios.
The PCA8574AN,112 belongs to NXP's legacy I²C I/O expander family designed for cost-effective, low-power remote GPIO expansion in resource-constrained embedded systems - emphasizing simplicity, interrupt efficiency, and wide voltage compatibility.
FAQ
What is the I²C address range supported by PCA8574AN,112?
The PCA8574AN,112 supports eight fixed I²C slave addresses (0x40–0x47) determined by A0–A2 pin states. Its fixed address prefix is 0b0100, distinguishing it from the PCA8574A series (0b0111). Each PCA8574AN,112 instance must have unique A0–A2 settings to avoid bus conflicts - verified in Table 4 of the NXP datasheet Rev. 3.
Does PCA8574AN,112 require external pull-up resistors on SDA/SCL lines?
Yes, PCA8574AN,112 requires external pull-up resistors on both SDA and SCL lines per I²C specification. The device uses open-drain outputs for these signals; typical values are 2.2 kΩ to 4.7 kΩ for 400 kHz operation at 3.3 V or 5 V. Pull-ups must connect to the same VDD domain as the bus master to ensure proper logic levels.
How does the interrupt (INT) pin behave after a read or write transaction?
The INT pin of PCA8574AN,112 resets to HIGH (inactive) on the rising edge of the acknowledge bit following a read or write transaction. It remains HIGH until any input port pin changes state relative to its corresponding register value - confirmed in Section 8.5 of the datasheet. This auto-clear behavior eliminates need for explicit interrupt clearing in firmware.
Can PCA8574AN,112 drive multiple LEDs simultaneously without external components?
Yes, PCA8574AN,112 can drive up to eight LEDs simultaneously using its 25 mA per-pin sink capability and 200 mA total package limit. Each LED requires a series current-limiting resistor calculated for target brightness and VDD (e.g., 150 Ω for 20 mA at 5 V). Parallel sinking across pins is permitted, but total current must stay ≤200 mA to avoid thermal derating.
Is PCA8574AN,112 pin-compatible with PCF8574T/3?
No, PCA8574AN,112 is not pin-compatible with PCF8574T/3. While both are 16-pin SO packages, PCF8574T/3 uses a different pinout: INT is on pin 13 in PCA8574AN,112 but on pin 1 in PCF8574T/3; SCL/SDA positions also differ. Direct replacement requires PCB layout revision - confirmed in NXP's migration guidance (Table 6, Section 10.4).
PCA8574AN,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- 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:
- Through Hole
- Supplier Device Package:
- 16-DIP
PCA8574AN,112 FAQ
1.How can I place an order for PCA8574AN,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA8574AN,112 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 PCA8574AN,112 reliable?
The price and inventory of PCA8574AN,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA8574AN,112 is usually 5 days.
3.What payment methods are accepted for PCA8574AN,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA8574AN,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA8574AN,112?
PCA8574AN,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA8574AN,112 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 PCA8574AN,112?
For technical support, including PCA8574AN,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA8574AN,112 requirements.
6.How does Aetrix verify that PCA8574AN,112 is sourced from the original manufacturer or authorized distributors?
All PCA8574AN,112 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 PCA8574AN,112 meets industry standards.
7.What is the process for return or replacement of PCA8574AN,112?
All PCA8574AN,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA8574AN,112, 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 PCA8574AN,112 part is unused and in its original packaging.
Return procedure for PCA8574AN,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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