Texas Instruments TCA9548APWR

Overview

TCA9548APWR from Texas Instruments is an 8-channel bidirectional I²C bus switch with voltage-level translation, active-low reset, and hardware address selection via A0–A2 pins. It operates from 1.65 V to 5.5 V, supports up to 400 kHz clock frequency, and enables channel-selectable isolation of I²C targets-e.g., resolving address conflicts among eight identical temperature sensors in a server backplane.

For engineers reviewing the TCA9548APWR datasheet, TCA9548APWR pinout, TCA9548APWR application, or TCA9548APWR equivalent, key selection criteria include its 24-pin TSSOP (PW) package, 5-V-tolerant I/Os, low R_ON (≤10 Ω at 5 V), standby current ≤2 µA at 5.5 V, and support for hot insertion and power-up glitch-free initialization.

Technical Context

The TCA9548APWR implements eight independent bidirectional pass-gate switches controlled by a single 8-bit I²C register, where each bit enables one SCn/SDn channel pair. Its architecture allows simultaneous or individual channel selection without bus contention, and internal logic ensures all channels power up deselected.

It features dual reset mechanisms: an active-low RESET pin (t_W(L) ≥6 ns) and a power-on reset triggered when V_CC crosses VPORR (1.2–1.5 V) on rise or VPORF (0.8–1.0 V) on fall. All I/Os are 5-V tolerant, and voltage translation is achieved via external pull-up resistors tied to different V_DPUx rails per channel.

Key Specifications

Pinout & Package

TCA9548APWR is packaged in a 24-pin TSSOP (PW) with nominal body size 7.80 mm × 4.40 mm, lead pitch 0.65 mm, and exposed thermal pad not present. Pin numbering follows JEDEC MO-153 standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C bus switching applications.

Compared with the TCA9548APWR, the PCA9548AD offers identical functionality but narrower voltage range and marginally higher conduction loss, while the ADG732BRUZ provides greater channel density at the cost of losing native I²C integration, reset capability, and voltage translation support-making it unsuitable as a drop-in replacement.

Availability

TCA9548APWR is available at Aetrix Electronics and suitable for server backplanes, industrial PLCs, and telecom switching equipment requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TCA9548APWR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity solutions, with decades of expertise in interface and power management ICs.

The TCA9548A product line was designed specifically to resolve I²C address conflicts and enable voltage-translation-aware bus expansion in space-constrained, multi-peripheral systems such as servers, routers, and factory automation controllers.

FAQ

What is the function of the RESET pin on the TCA9548APWR?

The RESET pin on the TCA9548APWR is an active-low asynchronous input that forces deselection of all eight I²C channels and reinitializes the internal state machine. When asserted for ≥6 ns, it clears any stuck bus condition on downstream SCn/SDn lines without cycling V_CC. The pin must be pulled up externally to V_CC; leaving it floating may cause unpredictable behavior. This feature is critical for recovering from I²C bus lockups in mission-critical systems like telecom switches and servers.

Can the TCA9548APWR translate between 1.8 V and 5 V I²C buses?

Yes, the TCA9548APWR supports voltage-level translation between 1.8 V, 2.5 V, 3.3 V, and 5 V I²C buses. This is achieved by connecting external pull-up resistors on each SCn/SDn pair to their respective target voltage rails (e.g., 1.8 V for a sensor, 5 V for a legacy peripheral), while the upstream SCL/SDA lines are pulled to the controller's V_DPUM. The TCA9548APWR's 5-V-tolerant I/Os and pass-gate architecture ensure signal integrity across combinations-no additional level-shifting ICs are required.

How many TCA9548APWR devices can share the same I²C bus?

Up to eight TCA9548APWR devices can operate on the same I²C bus, enabled by three hardware address pins (A0, A1, A2). Each pin can be tied high or low, yielding eight unique 7-bit slave addresses (70h–77h hexadecimal). This allows hierarchical expansion-for example, one TCA9548APWR managing eight sensors per slot, with eight slots addressed individually. No software address remapping is needed; configuration is purely hardware-based and static.

What is the maximum capacitive load the TCA9548APWR can drive on a downstream channel?

The TCA9548APWR supports downstream I²C bus loads up to 400 pF per SCn/SDn channel, consistent with Fast Mode I²C specifications. Its output fall time (t_ocf) remains ≤300 ns under this load when driven with appropriate pull-up resistors. To maintain timing compliance at 400 kHz, designers must limit total trace + device capacitance on each channel to ≤400 pF and select pull-up values accordingly-typically 1–10 kΩ depending on V_DPUx and rise-time requirements. Exceeding this limit risks setup/hold violations and communication failures.

Does the TCA9548APWR require external pull-up resistors?

Yes, the TCA9548APWR requires external pull-up resistors on all I²C lines: upstream SCL/SDA must be pulled to V_DPUM, and each downstream SCn/SDn pair must be pulled to its respective V_DPUx rail. Pull-up values depend on bus speed, capacitance, and voltage-e.g., 2.2 kΩ for 400 kHz at 3.3 V with 20 pF load. Omitting pull-ups will prevent proper logic-level transitions, resulting in bus failure. The TCA9548APWR itself contains no internal pull-ups; all are external and application-defined.