PCA9535EDTR2G

PCA9535EDTR2G is NXP’s 16-bit I/O expander with I2C. It adds 16 bidirectional GPIOs (two 8-bit ports) to a microcontroller, configurable as input or output, with interrupt-on-change via an INT pin. It uses a standard I2C interface and three address pins (A0–A2), allowing up to eight devices on the bus. The device retains GPIO state in registers and supports reading/writing via I2C. This variant (EDTR2G) denotes the package/packaging (Tape & Reel, RoHS-compliant) used for procurement. Operating voltage is 2.3–5.5 V and it’s suitable for low-power, space-constrained I/O expansion. Typical uses include extending MCU I/O for LED driving, button/switch scanning, sensor interfacing, and general-purpose I/O expansion in embedded systems or PLC-style applications.

Common equivalents (16-bit I2C I/O expanders):
- Microchip MCP23017
- NXP PCF8575
- TI TCA9535
- NXP PCA9555
These offer similar 16-bit I/O expansion via I2C and can substitute for PCA9535EDTR2G in many designs (check register maps and timing).

Key features of PCA9535EDTR2G:
- 16-bit I/O expander for I2C with two 8-bit ports (P0 and P1)
- Programmable per-pin I/O direction (IODIR): each pin input or output
- Per-pin input polarity inversion (IPOL)
- Interrupt capability: INT output (open-drain); per-pin interrupt enable (GPINTEN) with configurable condition (INTCON/DEFVAL)
- Read/modify/write friendly: separate Input Port and Output Port registers with internal latches
- I2C interface supporting standard and fast modes (up to 400 kHz)
- Addressing: 3 hardware address pins (A0–A2) allowing up to 8 devices on the bus
- Registers available for control/status: IODIR, IPOL, GPINTEN, DEFVAL, INTCON, IN, OUT
- Wide supply range: typically 2.3 V to 5.5 V
- Low-power operation suitable for battery-powered or power-constrained designs
Note: Exact pinout/package details are indicated by the EDTR2G code but features above describe the device capabilities.

Pin count: 24 pins.
Function (concise):
- PCA9535EDTR2G is a 16‑bit I2C-bus general-purpose I/O expander.
- Provides two 8-bit ports (P0_0..P0_7, P1_0..P1_7) with individually configurable direction (input/output), input, output and polarity-inversion registers.
- I2C interface pins: SDA, SCL; three hardware address pins (A0, A1, A2) for up to 8 devices on the bus; active‑low interrupt output (INT).
- Supply and ground: VDD, GND.
- Typical supply voltage range: 2.3 V to 5.5 V.

Manufacturer: NXP Semiconductors N.V.
What kind of company: NXP is a global Dutch semiconductor company that designs and supplies integrated circuits and system solutions (mixed‑signal, digital and RF). It serves automotive, industrial, IoT, mobile and secure‑connectivity markets and is a major supplier of microcontrollers, power management, RF, secure ID and interface devices.

PCA9535EDTR2G is a 16-bit I2C I/O expander. Common application areas include:
- Extending MCU/SoC GPIOs over I2C when pins are limited
- Keyboard/keypad scanning and button input
- LED indicators and low-power drive applications
- Interface to sensors and external peripherals requiring digital I/O
- Industrial control panels, home automation, and consumer electronics
- Prototyping and development boards needing extra pins
- Embedded systems and SBCs to add GPIO without extra hardware
Note: Suitable for moderate current per pin; used where simple digital I/O expansion over I2C is needed.

PCA9535EDTR2G comes in a 16-pin TSSOP package (TSSOP-16).