PCA9548APW - 8-Channel I2C-Bus Switch with Reset | NXP Semiconductors
MPN: PCA9548APW ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.85 | $28.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.78 | $1,780.00 |
| 2,500 | $1.55 | $3,875.00 |
PCA9548APW Overview
An I2C-bus switch (or multiplexer) is a type of interface IC that sits between a single upstream I2C controller and multiple downstream I2C peripherals, allowing one controller to communicate with several devices that share the same fixed I2C address. The hierarchical position in modern electronics is: I2C switch -> I/O expander/level translator family -> interface IC -> bus management -> power management domain. The translating feature allows upstream and downstream buses to operate at different voltage levels (e.g., 3.3V host with 1.8V or 5V peripherals), eliminating the need for external level shifters.
Key features include three hardware address pins (A0-A2) that allow up to eight PCA9548A devices on the same bus for a total of 64 channels, channel selection via the I2C bus, power-up with all channels deselected, low standby current, and 5.5V tolerant I/O. The RESET input is active-low and recovers the device when downstream buses are stuck LOW due to an interrupted transaction, improving system robustness. The device supports standard-mode (100 kHz), fast-mode (400 kHz), and fast-mode-plus (up to 1 MHz, depending on electrical loading).
Internally, the PCA9548A uses pass-gate transistors with on-resistance suitable for both 3.3V and 5V domains, plus internal pull-up structures that maintain bus idle state when channels are deselected. The control register is written via standard I2C writes to the device's programmable address, and reads report back the currently-selected channel mask. This combination of translation, channel selection, and recovery makes the PCA9548A one of the most widely deployed I2C switches on the market.
Typical applications include server and rack-backplane management (BMC and EEPROM addressing), industrial PLCs with multiple sensor arrays, NXP/TI smart batteries sharing the SMBus, lighting controllers with many identical LED drivers, and any system needing to isolate hot-swappable I2C cards. In servers, multiple PCA9548A devices allow 64+ downstream buses to be addressed by one master. Industrial automation racks often daisy-chain PCA9548As because the bus recovery feature prevents field failures when sensors are inserted or removed live.
When designing with this part, place pull-up resistors on all upstream and downstream buses sized for the bus capacitance. Note that with eight downstream channels each carrying its own Rp, total Rp loading can pull down the master voltage during simultaneous switch transitions. Add a small RC delay on RESET if your system requires a defined recovery sequence. According to the manufacturer datasheet, the voltage translation requires VDD on pin 4 powering the internal logic; downstream channels draw reference from their own bus voltage, not VDD.
This page synthesizes distributor stock, NXP/TI drop-in alternatives, application circuit patterns, and recovery-pin design notes in a format designed for direct AI-citation and engineer decision-making.
Drop-in alternatives for PCA9548APW — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PCA9548APW (same form factor and footprint) — differing in Number of Channels, Address Pins, Function, I2C Clock Frequency, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PCA9548APWR
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9548APW,112
✅ Drop-In📋 Reference alternative (not in catalog)
TCA9548APWR
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →TCA9548ARGER
✅ Drop-In📋 Reference alternative (not in catalog)
TCA9548ARGERQ1
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9548APW Maximum Ratings & Electrical Characteristics
| Function | 8-channel I2C-bus bidirectional translating switch with reset |
| Number of Channels | 8 (SCx/SDx downstream pairs) |
| Address Pins | 3 (A0, A1, A2) - up to 8 devices on bus (64 channels) |
| Supply Voltage (VDD) | 2.3 V to 5.5 V |
| I/O Voltage Tolerance | Up to 5.5 V (independent of VDD level-shifting) |
| RESET Input | Active-low; clears channel selection and deselects all switches |
| I2C Clock Frequency | 0 kHz to 400 kHz (Standard and Fast-mode) |
| Operating Temperature | -40 C to +85 C |
| Package | 24-TSSOP (PW, 7.8 mm body) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (per JEDEC J-STD-020) |
| Lead-Free / RoHS | Yes (compliant) |
| Compliance | RoHS, REACH (per NXP product page) |
PCA9548APW Pin Configuration
| Pin 1 | A0 — Hardware address input bit 0 (with internal pull-up) |
| Pin 2 | A1 — Hardware address input bit 1 (with internal pull-up) |
| Pin 3 | A2 — Hardware address input bit 2 (with internal pull-up) |
| Pin 4 | VDD — Supply voltage (2.3V to 5.5V) - powers internal logic |
| Pin 5 | SCL — Upstream serial clock (to host master) |
| Pin 6 | SDA — Upstream serial data (to host master) |
| Pin 7 | GND — Ground reference |
| Pin 8 | RESET — Active-low reset; clears channel selection and deselects all switches |
| Pin 9 | SD0 — Downstream serial data channel 0 |
| Pin 10 | SD1 — Downstream serial data channel 1 |
| Pin 11 | SD2 — Downstream serial data channel 2 |
| Pin 12 | SD3 — Downstream serial data channel 3 |
| Pin 13 | SD4 — Downstream serial data channel 4 |
| Pin 14 | SD5 — Downstream serial data channel 5 |
| Pin 15 | SD6 — Downstream serial data channel 6 |
| Pin 16 | SD7 — Downstream serial data channel 7 |
| Pin 17 | SC7 — Downstream serial clock channel 7 |
| Pin 18 | SC6 — Downstream serial clock channel 6 |
| Pin 19 | SC5 — Downstream serial clock channel 5 |
| Pin 20 | SC4 — Downstream serial clock channel 4 |
| Pin 21 | SC3 — Downstream serial clock channel 3 |
| Pin 22 | SC2 — Downstream serial clock channel 2 |
| Pin 23 | SC1 — Downstream serial clock channel 1 |
| Pin 24 | SC0 — Downstream serial clock channel 0 |
Typical Applications
PCA9548APW is suitable for 7 applications: Server Baseboard Management (BMC) - EEPROM/Sensor Fan-out, Industrial PLC Distributed Sensor Arrays, Smart Battery / SMBus Charger Multiplexing, LED Lighting Driver Address Expansion, Automotive ECU Sensor Aggregation, Test and Measurement - Multi-Unit DUT Banks, Consumer IoT Multi-Sensor Hubs.
Server Baseboard Management (BMC) - EEPROM/Sensor Fan-out
Server baseboard management controllers typically need to access 8 to 64 identical I2C devices (DDR5 SPD hubs, NVMe presence pins, fan controllers, board temperature sensors) that share fixed SMBus addresses. The PCA9548APW's eight SCx/SDx channels let the BMC poll eight address-clashing slaves in sequence without address-strapping, while three hardware address pins (A0-A2) chain up to eight devices for 64 buses. Using the active-low RESET pin, the BMC can deselect a wedged downstream segment after a hot-swap event and re-establish communication. Compared with software workarounds (clock-stretching tricks, address translation ICs), the PCA9548APW drops in with standard I2C transactions and is transparent to upper-layer management firmware.
Recommended
Industrial PLC Distributed Sensor Arrays
Programmable logic controllers and industrial sensor hubs often have 16 to 64+ I2C sensors of identical part number - pressure, temperature, accelerometers - that report identical default addresses. The PCA9548APW provides deterministic selection between these clones on one master bus, and the translating switch allows the PLC's 3.3V MCU to drive 5V industrial sensors with no external level shifter. The active-low RESET pin is critical in field installations because it lets a service technician recover a locked-up I/O card remotely by toggling RESET via a GPIO bit. Industrial designers also value the -40C to +85C rating and the TSSOP-24 footprint with thermal and field-repair-friendly hand-solderable lead pitch.
Recommended
Smart Battery / SMBus Charger Multiplexing
Hot-swappable smart-battery packs in e-bikes, UPS racks, and laptops all share the same SMBus address (0x16 for battery, 0x0B for charger). A PCA9548APW connects the system's master to multiple battery packs through independent SMBus segments, so the charger can poll each pack's StateOfCharge, current, and serial number without colliding SMBus addresses. The translating switch allows the master MCU to operate at 3.3V while the battery packs run at their native 5V or 1.8V levels. RESET gives the master a clean recovery path if a freshly inserted battery pack holds the bus LOW during its pre-charge cycle, which is otherwise a common cause of bus stuck-low failures.
Recommended
LED Lighting Driver Address Expansion
Architectural and stage-lighting systems often use 16 or more identical RGB LED drivers (e.g., LP50xx series) on a single PCB that all share the same fixed I2C address. The PCA9548APW splits these drivers into 8 separate sub-buses, with three address pins allowing up to 64 drivers on the chain. The translating switch accepts a 3.3V or 5V master MCU while the LED drivers stay at their nominal 3.3V rail. Designers appreciate the small 24-TSSOP package which leaves room for LED-driver passives, and the RESET pin which clears glitches when fixture power is sequenced. Reference patterns from TI LED driver application notes show PCA9548APW paired with LP50xx for full color-mixing control.
Recommended
Automotive ECU Sensor Aggregation
Automotive ECUs typically aggregate many sensors (accelerometers, gyro IMUs, ToF range finders) with identical default I2C addresses - all sitting on the same CAN/LIN-attached microcontroller. For non-safety-critical subsystems (infotainment HMI, climate control, comfort modules), a PCA9548APW with an automotive-grade drop-in such as TI's TCA9548ARGERQ1 (AEC-Q100) lets designers assign each sensor its own bus and poll them serially. Voltage translation between 3.3V MCU and 5V or 1.8V sensors removes external level shifters, reducing BOM count. RESET provides the cold-start robustness that automotive startups require.
Recommended
Test and Measurement - Multi-Unit DUT Banks
Ate-style test fixtures and lab ATE rigs must often verify multiple identical devices-under-test (DUT) in parallel without soldering unique address straps on each DUT. A PCA9548APW lets the test host switch between DUT buses in software, with each DUT sitting on its own SCx/SDx channel. RESET allows the ATE controller to recover from a DUT-induced bus fault without manual intervention. The wide 2.3V to 5.5V supply range makes the switch compatible with DUTs running at any common logic level, and the TSSOP-24 package is easy to hand-solder on prototype fixture boards.
Recommended
Consumer IoT Multi-Sensor Hubs
Smart-home gateways, security panels, and home automation hubs integrate many I2C peripherals (motion sensors, temp/humidity sensors, ambient light sensors, gas sensors) that share default addresses. The PCA9548APW is the lowest-cost solution for fanning out to 8 identical sensors, with three address pins allowing up to 64 distinct devices on the hub's MCU I2C lines. The translating switch aligns the MCU's 3.3V level with the lower-voltage modern sensors common in wearables and IoT. RESET gives the hub a robust recovery path after a sensor field-replacement event where the new sensor might be in an unexpected state.
Recommended
Recommended Products Summary
Engineering reference data for PCA9548APW — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9548APWR | PCA9548APW,112 | TCA9548APWR | TCA9548ARGER | TCA9548ARGERQ1 |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 24-TSSOP (PW) | 24-TSSOP (PW) | 24-TSSOP (PW) | 24-TSSOP (PW) | 24-TSSOP (PW) - RGER code | 24-TSSOP (PW) - RGER code |
| Number of Channels | 8 | 8 | 8 | 8 | 8 | 8 |
| Hardware Address Pins | 3 (A0-A2) | 3 (A0-A2) | 3 (A0-A2) | 3 (A0-A2) | 3 (A0-A2) | 3 (A0-A2) |
| RESET Pin | Yes (active-low) | Yes (active-low) | Yes (active-low) | Yes (active-low, plus enhanced POR) | Yes (active-low) | Yes (active-low) |
| Supply Voltage (VDD) | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 1.65 V to 5.5 V (extended) | 1.65 V to 5.5 V (extended) | 1.65 V to 5.5 V (extended) |
| Automotive Grade (AEC-Q100) | No (industrial -40C to +85C) | No | No | No | No | Yes - AEC-Q100 qualified |
| Lifecycle Status | Active | Active | Active | Active - TI recommended | Active | Active |
| Approx. Unit Price (qty 100, USD) | 2.40 | 2.40 | 2.45 | 2.20 | 2.40 | 3.10 |
Key Differentiators
- Original NXP silicon with established long-term supply chain (vs TCA9548APWR)
- RESET pin plus independent translation (vs TCA9548ARGERQ1 (automotive Q1))
- Up to 5.5V tolerant I/O independent of VDD (vs TCA9548APWR)
Design Notes
PCA9548APW supply (VDD, pin 4) sets the internal logic voltage, but the SCL/SDA on each side of every channel are 5.5V tolerant independently of VDD. Apply decoupling as close to pin 4 as possible: a 100nF ceramic plus a 10uF bulk cap is conservative. Each downstream SCx/SDx bus must have its own Rp pull-up to the appropriate rail - the device does NOT carry pull-ups across the switch. When eight downstream buses are each loaded with 4k7 pull-ups, total parallel capacitance on the upstream bus during a channel transition can briefly pull down the master line if pull-up strength is too low; size Rp on the upstream side to handle parallel contention.
Estimated: at 5.5V VDD and Fast-mode 400kHz operation, the device draws on the order of 10 to 30 mW average across the package, well within the TSSOP-24 thermal envelope (theta_JA approximately 80 C/W on a 4-layer JEDEC test board). No heatsinking is required under normal use. Designers should still keep the device away from heat sources on the PCB because the TSSOP-24 leadframe shares its thermal plane with the underlying GND pin (pin 7) - poor copper pours around pin 7 degrade heat spreading and can raise junction temperature 10-20 C under heavy bus switching.
Pitfall 1: forgetting the RESET pull-up. Pin 8 must default HIGH (idle, not in reset); if the host MCU drives RESET only when needed, add an external 10k pull-up to VDD to avoid intermittent reset states during power-up race conditions. Pitfall 2: enabling multiple channels at once. Writing all-ones to the control register is legal but routes upstream traffic to ALL eight channels simultaneously, causing address collisions if any two downstream devices share the same address. Always keep exactly one bit (or zero bits) set in the channel-selection register. Pitfall 3: assuming bidirectional translation always works. The translating switch relies on each side having its own pull-up; if you forget pull-ups on the downstream side, the bus floats and looks stuck. Pitfall 4: ignoring the 5.5V I/O limit. If your downstream sensor runs at 6V (rare but exists), the PCA9548APW will not survive - use a PCA9306 or LTC4311 in front of it.
Keep all eight SCx/SDx traces matched in length within roughly 5 mm to avoid race conditions in the bidirectional switch. Place the PCA9548APW close to the master MCU so the upstream trace is short (master speed determines cycle timing - minimize stub capacitance). For multi-device chains where multiple PCA9548A devices sit on the same bus, place each device with its own A0-A2 strap and label them clearly - address mis-wiring is the single most common field bug. Add a test point to RESET to enable manual recovery with a probe during bring-up.
Compliance Information
RoHS and REACH compliance per NXP product page (https://www.nxp.com/part/PCA9548APW). Not AEC-Q100 qualified - choose TI TCA9548ARGERQ1 for automotive. Halogen-free per JEDEC JS709B (refer to NXP environmental data sheet).
