Overview
The PCA9548A, produced by Texas Instruments, is an 8-channel I2C/SMBus switch designed to manage and translate voltage levels between different I2C or SMBus segments. This device is particularly useful in resolving I2C slave address conflicts and enabling communication between devices operating at different voltage levels. The PCA9548A features eight bidirectional translating switches that can be controlled via the I2C bus, allowing for flexible channel selection and voltage translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses.
Key Specifications
| Specification | Value |
|---|---|
| Package | SSOP (DB) with 24 pins |
| Operating Temperature Range | -40°C to 85°C |
| Operating Power-Supply Voltage Range | 2.3 V to 5.5 V |
| Clock Frequency | 0 kHz to 400 kHz |
| ESD Protection | 2000-V Human-Body Model, 200-V Machine Model, 1000-V Charged-Device Model |
| Latch-Up Performance | Exceeds 100 mA per JESD 78, Class II |
| Standby Current | Low |
| RON Switches | Low |
| Reset Input | Active-Low |
| Hardware Address Pins | Three pins for up to eight devices on the I2C bus |
Key Features
- 1-of-8 Bidirectional Translating Switches
- I2C Bus and SMBus Compatible
- Active-Low Reset Input
- Three Hardware Address Pins for Use of up to Eight PCA9548A Devices on the I2C Bus
- Channel Selection Via I2C Bus
- Power-Up with All Switch Channels Deselected
- Low RON Switches
- Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
- No Glitch on Power Up
- Supports Hot Insertion
- Low Standby Current
- 5-V Tolerant Inputs
- ESD Protection Exceeds JESD 22 Standards
Applications
- Servers
- Routers (Telecom Switching Equipment)
- Factory Automation
- Products With I2C Slave Address Conflicts (e.g., Multiple, Identical Temperature Sensors)
Q & A
- What is the primary function of the PCA9548A?
The PCA9548A is an 8-channel I2C/SMBus switch that allows for voltage-level translation and channel selection via the I2C bus. - What voltage levels can the PCA9548A translate between?
The PCA9548A can translate between 1.8-V, 2.5-V, 3.3-V, and 5-V buses. - How many devices can be connected using the hardware address pins?
Up to eight PCA9548A devices can be connected on the I2C bus using the three hardware address pins. - What is the purpose of the active-low reset input?
The active-low reset input allows the system master to reset the PCA9548A in case of a time-out or other improper operation. - Does the PCA9548A support hot insertion?
Yes, the PCA9548A supports hot insertion. - What is the operating temperature range of the PCA9548A?
The operating temperature range is -40°C to 85°C. - What is the clock frequency range of the PCA9548A?
The clock frequency range is 0 kHz to 400 kHz. - Does the PCA9548A have ESD protection?
Yes, the PCA9548A has ESD protection exceeding JESD 22 standards. - How many channels can be selected simultaneously?
Any individual or combination of the eight channels can be selected. - What is the standby current of the PCA9548A?
The standby current is low.
