PCF8575CDWR

PCF8575CDWR is a 16‑bit I/O expander for I2C from NXP (Philips). It provides 16 quasi‑bidirectional I/O pins (P0–P15) to extend a microcontroller’s I/O. Two 8‑bit ports are accessible as P0–P7 and P8–P15. You write two data bytes to set the outputs; you read two bytes to get the current pin states. Addressing uses A0–A3, giving up to 16 devices on the same I2C bus; base 7‑bit address is typically 0x20, so the range is 0x20–0x2F. Pins operate as inputs or outputs via quasi‑bidirectional behavior with internal pull‑ups; a 0 actively drives low, while writing 1 leaves the line pulled high. It’s suitable for expanding I/O, reading switches, driving LEDs (with resistors), or interfacing simple peripherals. Supply voltage is usually 2.5–6 V, and it supports standard and fast I2C modes. The CDWR suffix denotes the specific package/ordering code for this device in NXP catalogs.

Common functional equivalents to the NXP PCF8575 (I2C 16-bit I/O expander) include:
- NXP PCA8575 / PCA9555
- Microchip MCP23017
- TI TCA9535 / TCA9555
- Semtech/IDT SX1509
Note: these parts differ in register maps, interrupts, polarity/config features and electrical behavior (quasi‑bidirectional vs. direction registers). Verify datasheets before substitution.

PCF8575CDWR is a 16‑bit I/O expander for I2C-bus. Key features:
- 16 quasi-bidirectional I/O pins (P0–P15) in two 8-bit ports; each pin can be input or output via port registers.
- I2C interface supports standard/fast modes; 7-bit address with A2–A0 pins for up to 8 devices (base 0x20–0x27).
- Two-byte writes to set outputs; two-byte reads to read inputs.
- Interrupt output (INT) to signal input changes (optional).
- Operating voltage: 2.3–6 V (VDD); low standby current.
- Industrial temperature range (typical): -40 °C to 85 °C.
- RoHS-compliant packaging (CDWR).

The PCF8575CDWR is a 24-pin device. It is a 16-bit I2C-bus I/O expander (two 8-bit ports) providing 16 quasi‑bidirectional general-purpose I/O pins. Key pins/functions:
- SDA, SCL: I2C data and clock
- A0, A1, A2: hardware address inputs (up to 8 devices)
- INT: open-drain interrupt/output (active low)
- P00–P07, P10–P17: 16 I/O lines
- VDD, VSS: power supply pins
Typical use: add 16 GPIOs to a microcontroller via I2C.

The PCF8575CDWR is manufactured by NXP Semiconductors. NXP is a Dutch multinational semiconductor company (formerly Philips Semiconductors) that designs and manufactures integrated circuits and system solutions for automotive, industrial, IoT, mobile, and communication applications.

PCF8575CDWR is a 16-bit I2C I/O expander. Common applications include:
- Expanding MCU/SBC GPIOs (Arduino, Raspberry Pi, ESP) over I2C
- Reading 16 switches/sensors and driving 16 LEDs or relays via drivers
- Keypad matrices and LCD backlight control
- General I/O interface in home/industrial automation, instrumentation, robotics
- Prototyping and test fixtures needing many GPIOs
It’s suitable for any system needing inexpensive, two-wire GPIO expansion.

The PCF8575CDWR is supplied in a 16-pin SOIC surface-mount package (SO16) and typically delivered on tape-and-reel (reel packaging).