PCA9544ARGYR

PCA9544ARGYR is NXP’s PCA9544A 4-channel I2C switch (multiplexer) in RoHS/tape‑and‑reel packaging. It lets a single I2C master talk to four independent downstream buses, isolating each channel when needed to prevent address conflicts, reduce bus capacitance, and improve noise immunity.
How it works:
- The master talks to the PCA9544A over SCL/SDA.
- A single I2C control byte (low nibble P0–P3) enables or disables each channel (SDA/SCL pair) individually.
- Enabled channels connect their downstream devices to the master; disabled channels are isolated.
Typical use:
- Attach four slave devices (often with conflicting addresses or different voltage/pullups) on channels 0–3.
- Write a control byte to select the active channel(s) (e.g., 0x01 enables channel 0; 0x0F enables all four).
Key notes:
- Supports standard I2C operation (up to 400 kHz) from a common supply (roughly 2.3–5.5 V).
- Suffix GYR indicates RoHS-compliant, lead-free packaging and reel.
Ideal for multi‑sensor arrays, system-on-module I2C buses, and improving layout without extra masters.

Equivalent devices (4-channel I2C bus switch/multiplexer):
- NXP PCA9544A (same family; packaging differs)
- Texas Instruments TCA9544A (4-channel I2C switch)
Other vendors offer similar 4-channel I2C switches; cross-compatibility varies, so check pinout/addressing if substituting.

Concise features of PCA9544ARGYR (4-channel I2C bus switch/multiplexer):
- 4-channel, bidirectional I2C switch to create separate downstream buses (channels 0–3) from a single master.
- Independent channel enabling via a single 4-bit control byte written over I2C.
- Isolates downstream buses when disabled to prevent cross-talk and address conflicts.
- Works with standard-mode and fast-mode I2C (up to 400 kHz).
- Supply voltage range typically 2.3 V to 5.5 V; no level shifting between buses (voltage must be within Vcc).
- Three hardware address pins (A0–A2) for multiple devices on the same bus (up to eight PCA9544A devices).
- Master accesses any devices behind a selected channel as if they were on the main bus.
- RoHS-compliant packaging (ARGYR indicates the package type).

Pin count: 16 pins (PCA9544A in a 16‑pin package, RoHS variant).
Function: Quad I2C-bus switch/multiplexer. It provides one upstream I2C bus (SDA, SCL) and four downstream buses (SDA1/SCL1 to SDA4/SCL4). Each downstream channel can be enabled/disabled via a control register; A0–A2 set the device I2C address. The channels are bidirectional I2C switches to isolate or connect sub-buses to the main bus.

- Manufacturer: NXP Semiconductors
- What kind of company: A Dutch multinational semiconductor company that designs and manufactures integrated circuits and system solutions for automotive, industrial, and consumer markets (formerly Philips’ semiconductor division).

PCA9544ARGYR is a 4-channel I2C switch/multiplexer. Common applications:
- Extend/segment I2C buses from one master to four downstream channels
- Isolate devices with identical I2C addresses (sensors, EEPROMs, ADCs, IO expanders) to avoid conflicts
- Reduce bus capacitance and improve signal integrity on long or noisy lines
- Allow individual power-down/hot-plug of downstream devices by gating channels
- Simplify PCB routing in complex systems
- Widely used in automotive, industrial, consumer electronics, wearables, and data-logging for sensor networks and peripheral multiplexing

16-pin TSSOP (Thin Shrink Small Outline Package).