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Home > Products > Integrated Circuits (ICs) > Interface > Controllers

NXP Semiconductors PCF8584T/2,518

Name: PCF8584T/2,518
Brand: NXP Semiconductors
SKU: PCF8584T/2,518
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PCF8584T/2,518

Manufacturer:: NXP Semiconductors

Category:: Controllers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: PCF8584T/2,518.pdf

Description:: IC CTRL PARALLEL/I2C BUS 20-SOIC

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Product details

Overview

PCF8584T/2,518 from NXP Semiconductors (formerly Philips) is a parallel-bus-to-I²C-bus protocol converter IC supporting both master and slave operation, with programmable SCL frequencies up to 90 kHz, −40 to +85 °C operating temperature range, and 4.5–5.5 V supply voltage. It interfaces 8051, Z80, 68000, and 8049 microcontrollers to I²C-bus systems in industrial control and embedded instrumentation.

For engineers reviewing the PCF8584T/2,518 datasheet, PCF8584T/2,518 pinout, PCF8584T/2,518 application, or PCF8584T/2,518 equivalent, key selection considerations include its dual-mode interface auto-detection (80XX/68000), long-distance 4-wire mode, monitor mode capability, interrupt vector programmability, and register-level control of START/STOP/ACK via S1.

Technical Context

The PCF8584T/2,518 implements full I²C-bus protocol handling-including arbitration, timing, START/STOP generation, ACK/NACK control, and multi-master conflict resolution-via dedicated internal logic and five mapped registers (S0–S3, S0′). Its parallel interface uses A0, WR/RW, RD/DTACK, CS, and RESET/STROBE to support asynchronous access across multiple CPU families.

It features three operational modes: standard 2-wire I²C-bus mode, 4-wire long-distance mode (requiring external line drivers), and passive monitor mode (enabled by zeroing S0′). Clock prescaling (S22–S24) adapts to input clock frequencies from 3 MHz to 12 MHz, while S20–S21 select one of four SCL output frequencies: 90 kHz, 45 kHz, 11 kHz, or 1.5 kHz.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/CMOS microcontroller buses without level-shifting.
Operating Temperature	−40 °C to +85 °C - supports deployment in industrial environments without derating.
Max SCL Frequency	90 kHz - enables high-speed I²C communication for time-critical sensor or EEPROM access.
I²C Bus Role	Master and slave - allows bidirectional integration into mixed-role I²C networks (e.g., MCU as master, PCF8584T/2,518 as slave peripheral).
Parallel Interface	8-bit bidirectional data bus (DB0–DB7) with mode-agnostic control (WR/RW, RD/DTACK, CS, A0) - eliminates need for bus-specific glue logic.
Interrupt Support	Programmable 8-bit vector (S3) with ENI-controlled open-drain INT output - enables direct integration with vectored-interrupt CPUs like 68000.
Special Modes	Monitor mode (S0′ = 00H), long-distance 4-wire mode (ES1=1, ESO=1), strobe mode (address+STOP triggers monostable pulse) - provides debug visibility, extended cabling, and bus arbitration signaling.

Pinout & Package

PCF8584T/2,518 is housed in a plastic small outline package (SO20), 20-lead, 7.5 mm body width (SOT163-1), with gull-wing leads suitable for surface-mount reflow soldering per JEDEC standards.

Pin/Terminal	Circuit Role	Design Meaning
CLK	Clock input	Accepts microcontroller clock source (3–12 MHz); drives internal prescaler and digital filters for SCL/SDA timing stability.
SDA / SDA OUT	Serial data I/O	Open-drain bidirectional I²C data line; becomes unidirectional output in long-distance mode.
SCL / SCL IN	Serial clock I/O	Open-drain bidirectional I²C clock line; becomes unidirectional input in long-distance mode.
IACK / SDA IN	Interrupt acknowledge input	Triggers vector readout on DB0–DB7 when ENI=1; serves as serial data input in long-distance mode.
INT / SCL OUT	Interrupt output	Open-drain active-low interrupt signal; repurposed as serial clock output in long-distance mode.
A0	Register select	High selects control/status register S1; low enables access to S0, S0′, S2, or S3 depending on ES1/ES2.
DB0–DB7	Parallel data bus	8-bit bidirectional port for register read/write; carries interrupt vector during IACK cycle.
RESET/STROBE	Reset input / strobe output	Active-low reset (≥30 CLK cycles); outputs 8-cycle monostable pulse on address+STOP in strobe mode.
CS	Chip select	Enables parallel bus access; used with WR/RW to auto-detect 80XX vs. 68000 interface mode.
WR (R/W)	Write control	Writes to registers when CS active; polarity and function adapt automatically to target CPU family.
RD (DTACK)	Read control	Reads registers or acknowledges data transfer; DTACK output in 68000 mode enables synchronous handshaking.
VDD, VSS	Power supply	5 V supply and ground pins - decoupling required per CMOS layout guidelines to suppress switching noise on I²C lines.

Key Features

Feature	Design Value
Auto-detect parallel interface mode	Identifies 80XX (8051/Z80) or 68000 bus timing on power-up using WR-CS sequence - eliminates manual configuration jumpers or firmware mode selection.
Programmable SCL frequency	Four selectable rates (90/45/11/1.5 kHz) via S20–S21, with clock prescaler (S22–S24) adapting to 3–12 MHz input clocks - ensures precise timing across diverse host oscillator sources.
Long-distance 4-wire mode	Reconfigures SDA/SCL pins as unidirectional SDA OUT, SCL IN, SDA IN, SCL OUT - enables RS-422/485-based extension beyond standard I²C 1 m limit.
Passive I²C bus monitor	Activated by writing 00H to S0′ - captures all I²C traffic without ACK generation or bus contention, ideal for protocol analysis and fault tracing.
Strobe output on address+STOP	Generates 8-clock-cycle active-low pulse at RESET/STROBE pin - provides hardware synchronization signal for multi-master parallel-bus arbitration.
Dual-register S0 architecture	Separate shift register (write-only) and read buffer (read-only) - prevents data corruption during concurrent transmit/receive operations and simplifies byte-handling firmware.

Applications

Industrial Sensor Hub	Legacy MCU I²C Bridge
Use Scenario: Central controller (8051) aggregates data from multiple I²C temperature, pressure, and humidity sensors in factory-floor equipment. IC Role / Device Role / Timing Role: PCF8584T/2,518 acts as master controller, initiating reads, managing arbitration, and buffering sensor responses on the I²C bus. Use Value: Enables legacy 8-bit microcontrollers without native I²C peripherals to drive modern I²C sensor arrays with deterministic timing and error recovery (BER detection, LAB flag).	Use Scenario: Retrofitting a Z80-based medical instrument with I²C EEPROM for calibration data storage. IC Role / Device Role / Timing Role: PCF8584T/2,518 operates as I²C slave, responding to Z80 writes/reads via its parallel interface while maintaining strict I²C timing compliance. Use Value: Eliminates need for custom FPGA or discrete logic; leverages existing Z80 bus timing and interrupt structure without modifying PCB layout or firmware architecture.
I²C Bus Monitor & Debugger	Multi-Master Industrial Network
Use Scenario: Field technician diagnosing intermittent I²C communication failures in a PLC backplane. IC Role / Device Role / Timing Role: PCF8584T/2,518 runs in monitor mode (S0′ = 00H), passively capturing START/STOP, addresses, and data bytes without affecting bus timing. Use Value: Provides real-time visibility into I²C traffic including ACK/NACK status (LRB bit), arbitration loss (LAB), and bus errors (BER) - no bus interruption or additional pull-ups required.	Use Scenario: Distributed control system where multiple 68000-based nodes share one I²C bus for shared memory and status reporting. IC Role / Device Role / Timing Role: Each PCF8584T/2,518 functions as multi-master node, detecting BB flag before transmission and asserting STO/STA under software control. Use Value: Hardware-enforced arbitration and automatic STOP/START chaining prevent bus lockup; strobe output synchronizes parallel-bus access across nodes.

Industrial Sensor Hub

Legacy MCU I²C Bridge

Use Scenario: Central controller (8051) aggregates data from multiple I²C temperature, pressure, and humidity sensors in factory-floor equipment.

IC Role / Device Role / Timing Role: PCF8584T/2,518 acts as master controller, initiating reads, managing arbitration, and buffering sensor responses on the I²C bus.

Use Value: Enables legacy 8-bit microcontrollers without native I²C peripherals to drive modern I²C sensor arrays with deterministic timing and error recovery (BER detection, LAB flag).

Use Scenario: Retrofitting a Z80-based medical instrument with I²C EEPROM for calibration data storage.

IC Role / Device Role / Timing Role: PCF8584T/2,518 operates as I²C slave, responding to Z80 writes/reads via its parallel interface while maintaining strict I²C timing compliance.

Use Value: Eliminates need for custom FPGA or discrete logic; leverages existing Z80 bus timing and interrupt structure without modifying PCB layout or firmware architecture.

I²C Bus Monitor & Debugger

Multi-Master Industrial Network

Use Scenario: Field technician diagnosing intermittent I²C communication failures in a PLC backplane.

IC Role / Device Role / Timing Role: PCF8584T/2,518 runs in monitor mode (S0′ = 00H), passively capturing START/STOP, addresses, and data bytes without affecting bus timing.

Use Value: Provides real-time visibility into I²C traffic including ACK/NACK status (LRB bit), arbitration loss (LAB), and bus errors (BER) - no bus interruption or additional pull-ups required.

Use Scenario: Distributed control system where multiple 68000-based nodes share one I²C bus for shared memory and status reporting.

IC Role / Device Role / Timing Role: Each PCF8584T/2,518 functions as multi-master node, detecting BB flag before transmission and asserting STO/STA under software control.

Use Value: Hardware-enforced arbitration and automatic STOP/START chaining prevent bus lockup; strobe output synchronizes parallel-bus access across nodes.

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C-bus controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
PCA9564	Successor IC with identical pinout, enhanced ESD rating (4 kV HBM), wider voltage range (2.7–5.5 V), and integrated clock generator (no external CLK required).	Supports lower-voltage hosts (e.g., 3.3 V ARM cores); eliminates external crystal/clock source; not drop-in compatible due to different reset behavior and S1 bit mapping.	Select PCA9564 for new designs requiring 3.3 V operation, higher robustness, or simplified BOM; retain PCF8584T/2,518 for legacy 5 V systems with existing CLK infrastructure.
PCF8584P	Same die, DIP20 package (SOT146-1) instead of SO20; identical electrical specs, timing, and register set.	Used in through-hole prototyping, repair, or legacy board upgrades where SOIC footprint is unavailable.	Choose PCF8584P only when mechanical constraints require DIP packaging; no functional difference - same firmware and schematic design applies.

Compared with PCA9564, PCF8584T/2,518 requires an external clock source and operates strictly at 5 V, but offers proven field reliability in industrial 8051/Z80 systems; compared with PCF8584P, it delivers identical functionality in a space-saving SOIC package optimized for automated assembly.

Availability

PCF8584T/2,518 is available at Aetrix Electronics and suitable for industrial automation, legacy MCU upgrade projects, and embedded instrumentation requiring stable component supply over extended product lifecycles.

Supply support for PCF8584T/2,518 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 heritage in I²C technology originating from Philips.

The PCF8584T/2,518 belongs to NXP's legacy I²C interface controller product line, designed specifically to bridge parallel-bus microcontrollers to I²C-bus peripherals in cost-sensitive, high-reliability industrial systems.

FAQ

What is the primary function of the PCF8584T/2,518 in a system?

The PCF8584T/2,518 serves as a parallel-bus-to-I²C-bus protocol converter, enabling microcontrollers like the 8051, Z80, or 68000 to communicate with I²C peripherals without native I²C hardware. It handles all I²C timing, arbitration, START/STOP generation, and ACK/NACK signaling internally - offloading these tasks from the host CPU and ensuring protocol compliance. The PCF8584T/2,518 is essential for integrating I²C sensors, EEPROMs, or RTCs into legacy parallel-bus architectures.

How does the PCF8584T/2,518 detect whether it is connected to an 80XX or 68000-type microcontroller?

The PCF8584T/2,518 detects interface type automatically during initialization by monitoring the WR (R/W) and CS signal sequence: a HIGH-to-LOW transition on WR while CS is HIGH selects 68000 mode and enables DTACK output, whereas default behavior assumes 80XX mode. This detection occurs once at power-up or after reset and requires stable WR and CS signals post-reset. No firmware configuration is needed - the PCF8584T/2,518 adapts transparently to either bus timing convention.

Can the PCF8584T/2,518 operate as both I²C master and slave simultaneously?

No - the PCF8584T/2,518 operates in either master or slave mode per transaction, determined by firmware control of the STA (START) and STO (STOP) bits in register S1. It supports multi-master arbitration and can respond as a slave when addressed, but cannot maintain concurrent master and slave sessions. Mode selection is dynamic and software-controlled; for example, a single PCF8584T/2,518 may act as master to read sensor data and later as slave to accept configuration updates - but not at the same time.

What is required to enable the long-distance 4-wire mode on the PCF8584T/2,518?

To enable long-distance mode, set ES1 = 1 and ESO = 1 in register S1, and ensure ENI = 0 before entry. In this mode, pins 2–5 become unidirectional: SDA OUT, SCL IN, SDA IN, and SCL OUT - requiring external RS-422/485 line drivers. The PCF8584T/2,518 must be isolated from the 4-wire bus until fully initialized, and synchronization shifts from interrupt-driven (INT) to polled (PIN bit), since INT is disabled. Standard I²C timing and register access remain unchanged.

Does the PCF8584T/2,518 support I²C clock stretching, and how is it implemented?

Yes - the PCF8584T/2,518 supports clock stretching via automatic SCL hold-off. When acting as slave receiver and PIN = 0, it holds SCL LOW until the read buffer S0 is accessed; when acting as slave transmitter and PIN = 0, it holds SCL LOW until the next data byte is written to S0. This behavior is hardware-managed and requires no firmware intervention - ensuring compliant clock stretching that prevents data overrun and maintains I²C bus timing integrity during slow host processing.

PCF8584T/2,518 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Programmable:: Not Verified

Protocol:: I2C

Function:: Controller

Interface:: Parallel

Standards:: -

Voltage - Supply:: 4.5V ~ 5.5V

Current - Supply:: 1.5mA

Operating Temperature:: -40°C ~ 85°C

Supplier Device Package:: 20-SO

Grade:: -

Qualification:: -

PCF8584T/2,518 FAQ

1.How can I place an order for PCF8584T/2,518 through Aetrix?

Please submit a Request for Quotation (RFQ) for PCF8584T/2,518 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 PCF8584T/2,518 reliable?

The price and inventory of PCF8584T/2,518 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCF8584T/2,518 is usually 5 days.

3.What payment methods are accepted for PCF8584T/2,518?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCF8584T/2,518 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PCF8584T/2,518?

PCF8584T/2,518 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PCF8584T/2,518 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 PCF8584T/2,518?

For technical support, including PCF8584T/2,518 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCF8584T/2,518 requirements.

6.How does Aetrix verify that PCF8584T/2,518 is sourced from the original manufacturer or authorized distributors?

All PCF8584T/2,518 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 PCF8584T/2,518 meets industry standards.

7.What is the process for return or replacement of PCF8584T/2,518?

All PCF8584T/2,518 units undergo pre-shipment inspection (PSI). If there is an issue with PCF8584T/2,518, 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 PCF8584T/2,518 part is unused and in its original packaging.

Return procedure for PCF8584T/2,518:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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