PCA9548ADB - 8-Channel I2C/SMBus Switch | Texas Instruments
MPN： PCA9548ADB ✓ 啟用中PCA9548ADB 概覽
An I2C switch, also called an I2C multiplexer or bus switch, is an interface IC that routes a shared SCL and SDA connection to one or more downstream peripherals. It belongs to the I2C interface-controller and bus-management hierarchy, where it helps overcome bus-capacitance and address limitations without requiring a separate microcontroller port for every device.
The PCA9548A family supports 1-of-8 bidirectional switch selection through the I2C control register. Three hardware address inputs allow as many as eight PCA9548A devices to coexist on the same upstream bus. An active-low reset input provides a hardware recovery path, while the power-up configuration selects all downstream channels according to the device configuration.
Voltage translation allows the upstream SCL and SDA signals to operate from a different voltage domain than the selected downstream channel. This makes the device useful when sensors, converters, EEPROMs, and other peripherals use supply rails that differ from the controller bus. The bidirectional switch also supports bus-level clock stretching because SCL and SDA are pass-through paths rather than internally regenerated signals.
Typical uses include sensor aggregation, industrial instrumentation, battery-powered portable systems, communications equipment, and embedded computing platforms that need more I2C endpoints than the main controller can support directly. The eight downstream channels reduce wiring complexity by sharing one upstream bus while allowing peripheral groups to remain isolated when they are not selected.
When assigning PCB connections, use the pin-description table in the manufacturer datasheet and preserve the common ground connection between every connected supply domain. Keep the upstream bus and selected downstream pair away from unrelated high-current or high-voltage switching nodes. The reset pin should be controlled so a wedged downstream device cannot prevent recovery of the complete bus network.
This page combines the manufacturer's product information, verified sourcing records, drop-in replacement analysis, comparison parameters, and practical bus-layout guidance. It is intended to help engineers evaluate the PCA9548ADB as a compact eight-channel I2C/SMBus translation and multiplexing solution.
直接替換替代品，適用於 PCA9548ADB — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此產品無可直接替換的替代品。
申請替代品PCA9548ADB 最大額定值與電氣特性
| Product Type | 8-channel bidirectional I2C/SMBus translating switch |
| Number of Channels | 8 channels |
| Operating Voltage Range | 2.3 V to 5.5 V |
| 介面類型 | I2C and SMBus |
| Switch Direction | Bidirectional |
| Reset Input | Active-low |
| Hardware Address Inputs | 3 address pins |
| Maximum Addressable Devices | 8 devices per upstream bus |
| Power-Up Channel State | Configurable through external hardware |
| 工作溫度範圍 | -40 °C to 85 °C |
| 封裝 | 24-pin SSOP (DB) |
| 安裝類型 | Surface mount |
| 腳位數 | 24 pins |
PCA9548ADB 腳位配置
| 腳位 1 | SCL0 — Downstream channel 0 clock signal |
| 腳位 2 | SDA0 — Downstream channel 0 data signal |
| 腳位 3 | SCL1 — Downstream channel 1 clock signal |
| 腳位 4 | SDA1 — Downstream channel 1 data signal |
| 腳位 5 | SCL2 — Downstream channel 2 clock signal |
| 腳位 6 | SDA2 — Downstream channel 2 data signal |
| 腳位 7 | SCL3 — Downstream channel 3 clock signal |
| 腳位 8 | SDA3 — Downstream channel 3 data signal |
| 腳位 9 | SCL4 — Downstream channel 4 clock signal |
| 腳位 10 | SDA4 — Downstream channel 4 data signal |
| 腳位 11 | SCL5 — Downstream channel 5 clock signal |
| 腳位 12 | SDA5 — Downstream channel 5 data signal |
| 腳位 13 | SCL6 — Downstream channel 6 clock signal |
| 腳位 14 | SDA6 — Downstream channel 6 data signal |
| 腳位 15 | SCL7 — Downstream channel 7 clock signal |
| 腳位 16 | SDA7 — Downstream channel 7 data signal |
| 腳位 17 | A2 — Hardware address input 2 |
| 腳位 18 | A1 — Hardware address input 1 |
| 腳位 19 | A0 — Hardware address input 0 |
| 腳位 20 | GND — Ground connection |
| 腳位 21 | RESET — Active-low reset input |
| 腳位 22 | VCC — Device supply input |
| 腳位 23 | SCL — Upstream clock signal |
| 腳位 24 | SDA — Upstream data signal |
典型應用
PCA9548ADB 適用於 6 應用s: Industrial Sensor Aggregation, Portable and Wearable Devices, Battery Management Systems, Communications and Network Equipment, Test and Measurement Systems, Embedded Data Acquisition.
Industrial Sensor Aggregation
The PCA9548ADB suits industrial acquisition boards that connect several groups of sensors over one shared I2C bus. Its eight selectable downstream channels let the controller address sensor clusters selectively instead of leaving every device permanently connected to the same electrical segment. The 2.3 V to 5.5 V operating range supports low-voltage sensors as well as 5 V peripherals, while active-low reset provides a recovery path when one downstream device holds SDA low. In a typical installation, each selected channel retains clock stretching because SCL and SDA are routed through bidirectional switch paths. A 24-pin SSOP package also preserves routing flexibility compared with a discrete network of analog switches.
推薦
Portable and Wearable Devices
The PCA9548ADB is useful in compact portable systems where power and routing area limit the number of direct I2C connections. Eight channels allow a wearable controller, sensor hub, or accessory interface to reach multiple low-power devices through one upstream SCL/SDA pair. The device's 2.3 V minimum operating voltage fits low-voltage digital systems, while voltage translation can accommodate peripherals operating at a different level. The SSOP-24 footprint avoids the larger area of eight discrete bilateral switches. Designers should still account for battery-domain shutdown behavior, because a disconnected peripheral may retain a bus path through its supply rail.
推薦
Battery Management Systems
The PCA9548ADB can organize multiple battery-related I2C peripherals into separately addressable groups, including cell monitors, current sensors, chargers, and fuel-gauge devices. The eight-channel structure helps isolate address conflicts and limits bus loading because only the required downstream path is enabled. Its active-low reset allows a system controller to restore communication after a peripheral stalls. The translating-switch function is valuable when a low-voltage monitoring domain communicates with a higher-voltage control domain. Designers should assign supply states carefully so unpowered downstream devices cannot back-power an enabled channel, and should use pull-ups only on rails that remain active during the intended operating state.
推薦
Communications and Network Equipment
In communications equipment, the PCA9548ADB can fan a management bus toward optical, network, or transceiver-related peripherals without creating one large shared capacitive node. Eight downstream channels provide separation between functional groups and allow unused channels to remain disabled. The 2.3 V to 5.5 V range supports multiple logic levels found in communication modules, and the reset input supports board-level bus recovery during initialization. For systems with redundant or hot-swap modules, channel enable state and device supply sequencing must be coordinated to prevent contention. The SSOP-24 package provides a practical pin count for routing upstream bus, downstream pairs, address straps, and control logic on a multilayer board.
推薦
Test and Measurement Systems
The PCA9548ADB is effective in test and measurement instruments that must connect several ADC, DAC, EEPROM, or calibration devices through a common serial interface. Independent channel selection reduces contention and lets the instrument isolate a subsystem during test or firmware update. The device's bidirectional translating architecture accommodates mixed-voltage peripherals and preserves clock stretching across an active channel. Active-low reset is useful when a test target has been power-cycled independently of the controller. System designers should use the manufacturer's timing and logic-level information to establish pull-up placement and ensure that disabled channels do not create leakage paths through powered-down peripherals.
推薦
Embedded Data Acquisition
The PCA9548ADB supports embedded data-acquisition platforms that combine several low-speed sensors, memory devices, and converters behind an I2C controller. Eight channels allow firmware to route the bus selectively, which can reduce contention and make diagnostics easier when a peripheral becomes unresponsive. The bidirectional paths support clock stretching, while the three address inputs allow several PCA9548A devices to be cascaded or co-located on the same upstream bus. The 24-pin SSOP package balances channel count with board-space efficiency. Hardware planning should reserve space for address straps, reset control, local supply decoupling, and bus pull-ups on the relevant voltage domains.
推薦
推薦產品摘要
工程參考資料，適用於 PCA9548ADB — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 |
|---|---|
| Package | 24-pin SSOP (DB) |
| Brand | Texas Instruments |
| Channel Count | 8 channels |
| Operating Voltage Range | 2.3 V to 5.5 V |
| Interface | I2C and SMBus |
| Switch Type | Bidirectional translating switch |
| Reset | Active-low reset input |
| Hardware Addressing | 3 address inputs supporting up to 8 devices |
| Operating Temperature Range | -40 °C to 85 °C |
主要差異化特點
- Provides eight individually selectable downstream bus channels (對比PCA9546A)
- Supports more downstream endpoints than a two-channel switch (對比PCA9545A)
- Combines channel selection, hardware addressing, reset, and voltage translation (對比PCA9548AD)
設計說明
Route the upstream SCL and SDA traces as a controlled shared-bus pair, then branch each downstream SCLx/SDAx pair according to the PCB layout guidance in the manufacturer datasheet. Keep the eight channel pairs physically associated with their destination devices and avoid routing them beside unrelated high-current switching nodes. Confirm the 24-pin DB package dimensions and lead pattern against the current board footprint before fabrication.
Place the required supply capacitor close to VCC and connect the ground reference to a low-impedance plane. Pull-ups for upstream and downstream buses must be referenced to the voltage domain used by that bus segment; incorrect pull-up placement can defeat the translating function or exceed a peripheral's input limits. Confirm downstream device power states so an unpowered peripheral cannot back-power a channel through its SDA or SCL path.
Do not treat the PCA9548ADB as an I2C controller: the upstream SCL/SDA pair still requires a bus controller, and downstream peripherals require their own addresses. Do not enable multiple channels that lead to devices with conflicting addresses unless the system intentionally isolates them. Also verify the active-low reset polarity and the power-up channel configuration with external address resistors before releasing reset in firmware.
Use the shortest practical upstream connection and keep pull-up resistance consistent with the total bus capacitance, number of enabled peripherals, bus speed, and voltage level. Because the switch is bidirectional, propagation delay and channel capacitance affect both controller writes and peripheral clock stretching. Review the manufacturer timing characteristics and rise-time requirements before selecting resistor values for fast-mode or faster I2C operation.
合規資訊
The manufacturer product-page information confirms the electrical function, package, pin count, and temperature range, but the cited product information does not state the individual compliance statuses. RoHS, REACH, AEC-Q100, lead-free, halogen-free, and conflict-minerals declarations therefore remain unknown.
