TCA9544APWR - 4-Ch I2C/SMBus Mux with Interrupt | TI
MPN: TCA9544APWR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.15 | $1.15 |
| 10 | $1.03 | $10.30 |
| 100 | $0.86 | $86.00 |
| 500 | $0.72 | $360.00 |
| 1,000 | $0.62 | $620.00 |
TCA9544APWR Overview
An I2C multiplexer (bus switch) is an interface IC that lets a single master SCL/SDA pair be shared among multiple downstream I2C buses. It sits in the interface IC hierarchy between the bus transceiver level and full protocol bridges: multiplexer -> I2C switch -> I2C/SMBus interface -> system bus management. Its core role is resolving slave address conflicts and providing voltage translation between buses that run at different logic levels.
Key features include four independently selectable SCn/SDn channel pairs controlled by a single 8-bit control register, integrated interrupt logic with four downstream interrupt inputs (INT0-INT3) and one open-drain master-side INT output, and a 3-bit address-select input (A0-A2) that places the device at one of eight I2C addresses for multi-mux systems. Pass-gate switch architecture enables true bidirectional translation between 1.65 V, 2.3 V, 3.3 V and 5 V buses without direction pins.
Technically, the device passes the upstream SCL/SDA pair to any single channel or combination of channels determined by the control register, which is written and readable via I2C. Because it is a passive pass-gate (not a buffered repeater), it adds minimal propagation delay but does not regenerate signal rise times, so total bus capacitance limits remain applicable.
Typical applications include resolving address conflicts between multiple identical sensors (temperature, accelerometers) on one controller, isolating capacitive loading in long or heavily populated I2C segments, and fan-out from an SMBus host in servers and industrial controllers.
Design consideration: because the pass-gate does not buffer, keep total downstream capacitance within the 400 pF I2C Fast-Mode limit; series resistance of the switch slightly increases rise times, so verify pull-up sizing at 400 kHz.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for TCA9544APWR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
TCA9545APWR
✅ Drop-In📋 Reference alternative (not in catalog)
TCA9546APWR
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9544APW
✅ Drop-In📋 Reference alternative (not in catalog)
MAX7368ATI+
✅ Drop-In📋 Reference alternative (not in catalog)
TCA9544APWR Specifications
| Function | 4-channel I2C/SMBus multiplexer with interrupt logic |
| Number of Channels | 4 (SC0/SD0 to SC3/SD3) |
| Supply Voltage Range | 1.65 V to 5.5 V |
| Bus Speed Support | Standard-Mode 100 kHz, Fast-Mode 400 kHz |
| Voltage Translation | Yes (bidirectional, 1.65 V to 5.5 V mixed buses) |
| Control Interface | Single 8-bit I2C control register (3 LSBs select channels) |
| Interrupt Logic | 4 interrupt inputs (INT0-INT3), 1 open-drain master INT output |
| Address Select Inputs | A0, A1, A2 (3-bit address selection) |
| Package | 20-TSSOP (PW) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C |
| MSL Level | 1 (260C unlimited) |
| RoHS Status | Compliant (ROHS3) |
| Type | Multiplexer, 1 x 1:4 |
TCA9544APWR Pin Configuration
| Pin 1 | A0 — Address select input 0 |
| Pin 2 | A1 — Address select input 1 |
| Pin 3 | A2 — Address select input 2 |
| Pin 4 | GND — Ground |
| Pin 5 | SD0 — Serial data, channel 0 |
| Pin 6 | SC0 — Serial clock, channel 0 |
| Pin 7 | SD1 — Serial data, channel 1 |
| Pin 8 | SC1 — Serial clock, channel 1 |
| Pin 9 | SD2 — Serial data, channel 2 |
| Pin 10 | SC2 — Serial clock, channel 2 |
| Pin 11 | SD3 — Serial data, channel 3 |
| Pin 12 | SC3 — Serial clock, channel 3 |
| Pin 13 | INT0 — Interrupt input, channel 0 |
| Pin 14 | INT1 — Interrupt input, channel 1 |
| Pin 15 | INT2 — Interrupt input, channel 2 |
| Pin 16 | INT3 — Interrupt input, channel 3 |
| Pin 17 | INT — Interrupt output to master (open-drain) |
| Pin 18 | SCL — Serial clock, upstream bus |
| Pin 19 | SDA — Serial data, upstream bus |
| Pin 20 | VCC — Supply voltage, 1.65 V to 5.5 V |
Typical Applications
TCA9544APWR is suitable for 6 applications: I2C Address Conflict Resolution, Industrial Sensor Networks, Server and SMBus Management, Battery-Powered and Portable Devices, Test and Measurement Instrumentation, Optical Modules and Telecom Line Cards.
I2C Address Conflict Resolution
Multiple identical slaves such as temperature sensors or accelerometers often ship with the same fixed I2C address. The TCA9544A places each conflicting device on its own downstream channel (SC0/SD0 to SC3/SD3) and the master enables one channel at a time via the 8-bit control register, eliminating address collisions without firmware address tricks. Because the pass-gate adds only a small series resistance at both 100 kHz and 400 kHz, sensor timing and ACK behavior are preserved. This is the lowest-cost and lowest-risk method for arrays of up to four identical sensors, and the A0-A2 pins allow stacking multiple muxes for larger arrays.
Recommended
Industrial Sensor Networks
Factory automation and process-control nodes frequently aggregate dozens of I2C sensors, EEPROMs and I/O expanders on one controller. The TCA9544A's 1.65 V to 5.5 V operating range allows 3.3 V controllers to talk to 5 V legacy sensors through bidirectional pass-gate translation, while the four INT0-INT3 inputs aggregate fault signals from each branch into a single master interrupt, reducing controller GPIO usage. Channel isolation also limits capacitive loading, keeping each branch within the 400 pF Fast-Mode budget. Its -40C to +85C rating matches industrial ambient requirements in the 20-TSSOP package.
Recommended
Server and SMBus Management
Baseboard management controllers use SMBus to monitor power supplies, hot-swap controllers, EEPROM SPD data and thermal sensors across multiple boards or slots. The TCA9544A fans out the BMC's single SMBus master pair to four slot segments, with the open-drain master INT output collecting fault interrupts from all segments so the BMC can poll only the asserted branch. The 1.65 V to 5.5 V supply accommodates 3.3 V management rails, and support for 100 kHz Standard-Mode matches legacy SMBus timing requirements commonly found in server management fabrics.
Recommended
Battery-Powered and Portable Devices
In battery-operated products, multiple low-voltage I2C peripherals share a constrained controller with one I2C port. The TCA9544A operates down to 1.65 V, matching modern 1.8 V sensor rails, and its passive pass-gate architecture consumes essentially no switching power when channels are deselected. Designers segment power-hungry peripherals onto separate channels so inactive buses can be electrically isolated, trimming leakage. The 20-TSSOP package fits fine-pitch portable layouts, and the single control-register write model keeps firmware simple on resource-limited MCUs.
Recommended
Test and Measurement Instrumentation
Bench instruments and automated test equipment often need to address several identical I2C calibration EEPROMs or sensor modules during manufacturing. The TCA9544A gives the test controller deterministic, software-controlled routing to one device at a time, and the A0-A2 pins allow eight muxes on one bus for 32-device coverage from a single master. Fast-Mode 400 kHz support shortens test-cycle times, while readable interrupt status in the control register lets the ATE system detect and localize a stuck device on any of the four branches without extra wiring.
Recommended
Optical Modules and Telecom Line Cards
SFP/QSFP-class optical modules expose I2C management interfaces, and line cards frequently host several cages that would otherwise conflict on the management bus. The TCA9544A routes the card MCU's SCL/SDA to each cage's management interface independently, while the four interrupt inputs collect module fault and interrupt flags into a single line for the MCU. The 3.3 V supply compatibility matches typical optical module management rails, and 400 kHz Fast-Mode operation supports the fast polling loops required by real-time link monitoring in telecom equipment.
Recommended
Recommended Products Summary
Engineering reference data for TCA9544APWR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | TCA9545APWR | TCA9546APWR | PCA9544APW | MAX7368ATI+ |
|---|---|---|---|---|---|
| Package | 20-TSSOP (PW) | 20-TSSOP (PW) - same | 20-TSSOP (PW) - same | TSSOP-20 - same | 20-TSSOP - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors | Analog Devices (Maxim) |
| Channels | 4 (1 x 1:4 mux) | 4 | 4 | 4 | 4 |
| Interrupt Logic | Yes (INT0-INT3 in, 1 INT out) | Yes (2-level, enable inputs + RESET) | No (active-low RESET instead) | Yes (INT0-INT3 in, 1 INT out) | Yes (interrupt monitoring) |
| Voltage Translation | Yes (single-level pass-gate) | Yes (two-level) | Yes (pass-gate) | Yes (pass-gate) | Yes (pass-gate) |
Key Differentiators
- Integrated 4-input interrupt aggregation (vs TCA9546APWR)
- Wider supply range than the NXP predecessor (vs PCA9544APW)
- Lower system complexity than two-level translator TCA9545A (vs TCA9545APWR)
Design Notes
Place the TCA9544A close to the I2C connector or master controller, and route each downstream SCn/SDn pair as a tightly coupled pair with a solid ground reference. Because the device is a pass-gate rather than a buffer, stub length on deselected channels acts as capacitive loading only when the channel is off, but when enabled, all downstream capacitance adds to the master bus. Keep each branch under roughly 100 pF if you need reliable 400 kHz Fast-Mode operation, and use separate pull-up resistors sized for the total enabled-bus capacitance.
A common mistake is treating the TCA9544A as a signal buffer: it does not regenerate edges, so long cables or heavily loaded buses can still violate I2C rise-time limits even though the mux itself passes signals. Another pitfall is forgetting that only selected channels pass interrupts to the master INT output planning-wise; downstream devices on disabled channels will not assert INT until their channel is enabled. Also verify A0-A2 strapping against other devices on the bus to avoid address collisions with the mux control address.
The TCA9544A operates from 1.65 V to 5.5 V, and the VCC level also defines the upstream bus logic levels. For mixed-voltage systems, power the mux at the master-side rail (for example 3.3 V) and let the pass-gate tolerate 5 V slave signals within ratings. Add a 0.1 uF ceramic decoupling capacitor directly at pin 20 with a solid ground via to pin 4. Estimated: the device draws only microamp-scale static supply current, so supply budgeting is rarely the limiting factor; bus pull-up resistor current typically dominates.
At 400 kHz Fast-Mode, the pass-gate series resistance of the switch adds to the effective pull-up path, increasing rise times on downstream channels. Estimated mitigation: with 3.3 V rails and 400 pF total bus capacitance, start with 1 kOhm pull-ups on the enabled channel and verify rise time against the I2C 300 ns Fast-Mode limit on the bench. If rise times fail, reduce pull-up values, shorten the branch, or add an active I2C buffer such as the TCA9517 on the offending segment.
Compliance Information
ROHS3 compliant and MSL 1 (260C unlimited) per distributor data (PartGenie/DigiKey). REACH, halogen-free and conflict-minerals status not stated in provided data.
