Low-voltage 8-channel bidirectional I2C / SMBus switch in a TSSOP-24 package. An upstream SCL/SDA pair fans out to eight downstream channels (SC0/SD0 ... SC7/SD7), selected through a control register, so you can put eight devices that share the same fixed I2C address on one bus without collisions. Three address pins allow up to eight muxes (64 channels) on the host bus, and an active-low RESET recovers a stuck channel. The default fix for I2C address clashes.

Pinout

Pin	Name	Type	Function
1	A0	input	I2C target address input bit 0. Hard-wire directly to VCC (logic 1) or GND (logic 0) to set the lower address bit of the TCA9548A's 7-bit I2C address, allowing up to eight devices on the same bus.
2	A1	input	I2C target address input bit 1. Hard-wire directly to VCC or GND to set the second address bit of the TCA9548A's 7-bit I2C address.
3	RESET	input	Active-low reset input. Asserting low resets the I2C/SMBus state machine, deselects all channels, and initializes the device without cycling power (VIL ≤ 0.3×VCC, VIH ≥ 0.7×VCC; min pulse width 6 ns). Tie to VCC or VDPUM through a pull-up resistor if unused.
4	SD0	bidirectional	Downstream channel 0 serial data line. Connect to VDPU0 (channel-0 pull-up reference voltage) through an external pull-up resistor. When channel 0 is selected in the control register, SD0 is bidirectionally coupled to SDA via a low-RON pass gate (RON ≈ 4Ω at 5V).
5	SC0	bidirectional	Downstream channel 0 serial clock line. Connect to VDPU0 through an external pull-up. Coupled to SCL through a pass gate when channel 0 is enabled.
6	SD1	bidirectional	Downstream channel 1 serial data line. Connect to VDPU1 through a pull-up resistor; coupled to SDA when channel 1 is selected.
7	SC1	bidirectional	Downstream channel 1 serial clock line. Connect to VDPU1 through a pull-up resistor; coupled to SCL when channel 1 is selected.
8	SD2	bidirectional	Downstream channel 2 serial data line. Connect to VDPU2 through a pull-up resistor; coupled to SDA when channel 2 is selected.
9	SC2	bidirectional	Downstream channel 2 serial clock line. Connect to VDPU2 through a pull-up resistor; coupled to SCL when channel 2 is selected.
10	SD3	bidirectional	Downstream channel 3 serial data line. Connect to VDPU3 through a pull-up resistor; coupled to SDA when channel 3 is selected.
11	SC3	bidirectional	Downstream channel 3 serial clock line. Connect to VDPU3 through a pull-up resistor; coupled to SCL when channel 3 is selected.
12	GND	power_in	Ground return for the supply and all I/O reference levels.
13	SD4	bidirectional	Downstream channel 4 serial data line. Connect to VDPU4 through a pull-up resistor; coupled to SDA when channel 4 is selected.
14	SC4	bidirectional	Downstream channel 4 serial clock line. Connect to VDPU4 through a pull-up resistor; coupled to SCL when channel 4 is selected.
15	SD5	bidirectional	Downstream channel 5 serial data line. Connect to VDPU5 through a pull-up resistor; coupled to SDA when channel 5 is selected.
16	SC5	bidirectional	Downstream channel 5 serial clock line. Connect to VDPU5 through a pull-up resistor; coupled to SCL when channel 5 is selected.
17	SD6	bidirectional	Downstream channel 6 serial data line. Connect to VDPU6 through a pull-up resistor; coupled to SDA when channel 6 is selected.
18	SC6	bidirectional	Downstream channel 6 serial clock line. Connect to VDPU6 through a pull-up resistor; coupled to SCL when channel 6 is selected.
19	SD7	bidirectional	Downstream channel 7 serial data line. Connect to VDPU7 through a pull-up resistor; coupled to SDA when channel 7 is selected.
20	SC7	bidirectional	Downstream channel 7 serial clock line. Connect to VDPU7 through a pull-up resistor; coupled to SCL when channel 7 is selected.
21	A2	input	I2C target address input bit 2. Hard-wire directly to VCC or GND to set the third address bit of the TCA9548A's 7-bit I2C address (base 1110_A2A1A0).
22	SCL	bidirectional	Upstream I2C serial clock bus (controller side). Connect to VDPUM (the controller's I2C reference voltage) through a pull-up resistor. Standard-mode up to 100 kHz, Fast-mode up to 400 kHz.
23	SDA	bidirectional	Upstream I2C serial data bus (controller side). Connect to VDPUM through a pull-up resistor. Open-drain output capable of sinking 6 mA at VOL = 0.6 V.
24	VCC	power_in	Supply voltage input, 1.65 V to 5.5 V (absolute max 7 V). Also sets the maximum high-level voltage that the internal pass gates will pass between the upstream and downstream I2C buses.

Key specifications

Parameter	Value
Type	8-channel bidirectional I2C switch
Channels	8 (SC0/SD0 ... SC7/SD7)
Addresses	3 pins (up to 8 devices / 64 channels)
Reset	Active-low RESET
Voltage translation	Channels can bridge different bus voltages
Supply voltage	1.65-5.5 V
Package	TSSOP-24
Body (L×W×H)	7.8 × 4.4 × 1.2 mm

Ordering variants

Same part, different packaging or reel option.

TCA9548APWR (TSSOP-24, tape & reel)

CAD (KiCad official)

Symbol: Interface_Expansion:TCA9548APWR
Footprint: Package_SO:TSSOP-24_4.4x7.8mm_P0.65mm
3D model: TSSOP-24 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (42 pp, sha256 2137822fd7128945, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF