PCF8575CPW - 16-Bit I2C I/O Expander with Interrupt | Texas Instruments
MPN: PCF8575CPW ✓ نشطPCF8575CPW نظرة عامة
An I/O expander is an interface IC that increases the number of general-purpose input and output lines available to a microcontroller or other embedded controller. The PCF8575CPW uses a two-wire serial bus with SCL and SDA signals, allowing 16 quasi-bidirectional ports to be accessed through a compact serial interface. This is particularly useful when a host controller has insufficient GPIO pins for buttons, relays, indicators, or other peripherals.
The PCF8575 family provides a 16-bit quasi-bidirectional port and an I2C interface. Its latched outputs support direct LED driving, while the quasi-bidirectional inputs can be read by the host through the serial bus. The device also includes an interrupt output, allowing the connected controller to respond when an input state changes rather than continuously polling every port.
The PCF8575CPW is designed for 4.5 V to 5.5 V VCC operation and uses address pins to allow multiple expanders to coexist on the same bus. The I2C interface operates at up to 400 kHz, making the device appropriate for embedded systems, control boards, industrial interfaces, and small peripheral expansion designs.
Typical applications include keypad scanners, LED indicator panels, relay and transistor control, sensor and switch input modules, and general-purpose I2C GPIO expansion. The 24-pin TSSOP package supports compact surface-mount layouts, while external pull-up resistors are normally required on SDA and SCL according to the bus implementation guidance in the manufacturer datasheet.
For new designs, check the PCF8575CPW pin description table and electrical characteristics in the manufacturer datasheet before assigning PCB tracks or selecting external pull-up resistors. The interrupt line and address pins require careful placement so that multiple expanders can be cascaded without address conflicts.
This page combines the manufacturer product information, distributor listing data, package details, comparison references, and application-oriented design guidance to support component selection and PCB implementation.
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PCF8575PWG4
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
PCF8575CPWRG4
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
PCF8575CPWRE4
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
PCF8575CPW المواصفات
| Device Type | 16-bit I2C/SMBus I/O expander with interrupt |
| Number of I/O Lines | 16 lines |
| Supply Voltage Range | 4.5 V to 5.5 V |
| I2C Maximum Frequency | 400 kHz |
| الواجهة | I2C/SMBus |
| Interrupt Output | Yes |
| Port Type | 16-bit quasi-bidirectional port |
| Output Drive Capability | High-current drive for direct LED driving |
| Address Inputs | 3 address inputs |
| العلبة | 24-pin TSSOP (PW) |
| Package Width | 4.40 mm |
| نوع التركيب | Surface mount |
تكوين أطراف PCF8575CPW
| دبوس 1 | P00 — Quasi-bidirectional I/O port 0, bit 0 |
| دبوس 2 | P01 — Quasi-bidirectional I/O port 0, bit 1 |
| دبوس 3 | P02 — Quasi-bidirectional I/O port 0, bit 2 |
| دبوس 4 | P03 — Quasi-bidirectional I/O port 0, bit 3 |
| دبوس 5 | P04 — Quasi-bidirectional I/O port 0, bit 4 |
| دبوس 6 | P05 — Quasi-bidirectional I/O port 0, bit 5 |
| دبوس 7 | P06 — Quasi-bidirectional I/O port 0, bit 6 |
| دبوس 8 | P07 — Quasi-bidirectional I/O port 0, bit 7 |
| دبوس 9 | P10 — Quasi-bidirectional I/O port 1, bit 0 |
| دبوس 10 | P11 — Quasi-bidirectional I/O port 1, bit 1 |
| دبوس 11 | P12 — Quasi-bidirectional I/O port 1, bit 2 |
| دبوس 12 | P13 — Quasi-bidirectional I/O port 1, bit 3 |
| دبوس 13 | P14 — Quasi-bidirectional I/O port 1, bit 4 |
| دبوس 14 | P15 — Quasi-bidirectional I/O port 1, bit 5 |
| دبوس 15 | P16 — Quasi-bidirectional I/O port 1, bit 6 |
| دبوس 16 | P17 — Quasi-bidirectional I/O port 1, bit 7 |
| دبوس 17 | A0 — I2C address input 0 |
| دبوس 18 | A1 — I2C address input 1 |
| دبوس 19 | A2 — I2C address input 2 |
| دبوس 20 | INT — Interrupt output |
| دبوس 21 | SCL — Serial clock input |
| دبوس 22 | SDA — Bidirectional serial data input and output |
| دبوس 23 | VDD — Power supply input |
| دبوس 24 | VSS — Ground reference |
التطبيقات النموذجية
PCF8575CPW مناسب لـ 6 التطبيقs: LED Indicator Panel, Relay and Transistor Control, Keypad and Switch Input Panel, Industrial Sensor Interface, Remote I2C GPIO Module, Embedded Control and Data Acquisition.
LED Indicator Panel
The PCF8575CPW fits compact LED panels because it provides 16 latched quasi-bidirectional outputs with high-current drive capability for directly driving LEDs. The controller can update multiple indicators through the 4.5 V to 5.5 V I2C interface at up to 400 kHz instead of dedicating a GPIO pin to every lamp. This reduces wiring and frees controller pins for sensors or communications. Use the manufacturer output-current and voltage limits to select series resistors, and account for the total supply-current demand when sizing the local 5 V rail and bypass capacitor.
موصى به
Relay and Transistor Control
The PCF8575CPW can control relay drivers, MOSFET gates, and other digital loads when its output ratings and drive limits are appropriate. Its 16-bit port maps each I2C data update to a defined output state, making it practical for multi-channel industrial interface boards. The 400 kHz bus capability allows the host to update many channels quickly, although the interrupt output is more commonly associated with input changes than output completion. Confirm output voltage and sink/source current against the driver stage, and provide adequate supply decoupling for switching transients.
موصى به
Keypad and Switch Input Panel
A PCF8575CPW can extend a controller with up to 16 quasi-bidirectional input or output lines for keypads, limit switches, and panel controls. The serial interface reduces connector and routing requirements compared with direct GPIO expansion, while the interrupt output lets the host respond to input changes. Firmware must account for the quasi-bidirectional port architecture and establish each input state correctly. Debounce, pull-up or pull-down arrangements, and logic thresholds should be verified against the manufacturer application information before finalizing the circuit.
موصى به
Industrial Sensor Interface
The PCF8575CPW is useful when an industrial controller needs to collect digital sensor or interlock signals while keeping the remote wiring organized over I2C. Sixteen port lines provide flexible channels for limit switches, contactors, alarm inputs, or digital sensors within the 4.5 V to 5.5 V supply range. The interrupt line supports event-driven firmware, reducing unnecessary bus polling. Ensure every attached signal remains within the device's input thresholds, isolate noisy industrial wiring where necessary, and use address pins to avoid conflicts when several expanders are installed.
موصى به
Remote I2C GPIO Module
The PCF8575CPW can serve as the core of a remote GPIO module connected to a host board through short I2C wiring. Its 16-bit port, three address inputs, and interrupt output make it suitable for scalable control cards with buttons, indicators, and digital inputs. The 400 kHz interface helps maintain update performance across a multi-expander system, while the 24-pin TSSOP package supports compact surface-mount construction. Place SDA and SCL pull-up resistors according to bus capacitance, keep the ground return compact, and verify address uniqueness in firmware.
موصى به
Embedded Control and Data Acquisition
The PCF8575CPW can add digital monitoring and control channels to embedded acquisition equipment that already uses I2C for sensors. Instead of consuming a bank of host GPIO pins, the expander carries switch states and output commands over the same two-wire bus. The interrupt line helps the firmware react promptly to external state changes, and the 16 latched outputs can drive indicators. Keep bus loading within the controller's capability, observe pull-up resistor requirements, and account for the device's 4.5 V to 5.5 V operating range during system power design.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ PCF8575CPW — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | PCF8575PWG4 | PCF8575CPWRG4 | PCF8575CPWRE4 |
|---|---|---|---|---|
| Package | 24-TSSOP (PW) | 24-TSSOP (PW) | 24-TSSOP (PW) | 24-TSSOP (PW) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Device Function | 16-bit I2C/SMBus I/O expander with interrupt | PCF8575 16-bit I/O expander | PCF8575C 16-bit I/O expander | PCF8575C 16-bit I/O expander |
| Number of I/O Lines | 16 lines | 16 lines | 16 lines | 16 lines |
| Interrupt Output | Yes | Yes | Yes | Yes |
| Port Architecture | 16-bit quasi-bidirectional port | 16-bit quasi-bidirectional port | 16-bit quasi-bidirectional port | 16-bit quasi-bidirectional port |
أبرز الفروقات
- Provides 16 I/O lines in a compact 24-pin TSSOP (مقابلPCA9534PWR)
- Uses the established PCF8575C function and package (مقابلPCF8575PWG4)
- Combines I2C control with an interrupt output (مقابلPCF8575CPWRG4)
ملاحظات التصميم
Route SDA and SCL as a compact, continuous bus pair and place their pull-up resistors near the bus master or the electrically appropriate end of the bus. Keep the PCF8575CPW address-input traces short and away from switching-node and high-current return paths. The INT output should also be routed away from noisy digital edges because it can trigger host interrupt service routines.
Do not treat the quasi-bidirectional port as a general-purpose push-pull GPIO. Writing a logic 1 enables the port's weak pull-up behavior, which affects how external devices can override a pin. Use the input, output, and drive-current guidance in the manufacturer datasheet when connecting LEDs, relays, or transistor stages, and validate every state during power-up and reset.
Place the local supply bypass capacitor close to the device's VDD and VSS pins, and size the 5 V source for the sum of the expander load and any externally driven output current. If outputs switch relays or other inductive loads, keep their transient current outside the expander's I/O path and use appropriate driver circuitry. Confirm the maximum output current and supply limits before finalizing the board.
Assign unique hardware addresses when multiple PCF8575 devices share one bus, and record the resulting addresses in firmware. A duplicate A0-A2 configuration can cause contention or incorrect device access. Also verify that every device on the shared bus supports the intended 400 kHz rate; otherwise, select a lower bus speed in software.
معلومات الامتثال
The verified product information does not explicitly state the requested compliance classifications.