Overview
The PCA9508D,118 is a CMOS integrated circuit produced by NXP USA Inc., designed as a hot swappable level translating I²C-bus repeater. This device supports hot-swap with zero offset and provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) for I²C-bus or SMBus applications. It is particularly useful in systems where I/O cards need to be inserted into a live backplane without corrupting the data and clock buses.
Key Specifications
| Name | Value |
|---|---|
| Type | Buffer, ReDriver |
| Mounting Type | Surface Mount |
| Package / Case | 8-SOIC (0.154, 3.90mm Width) |
| Operating Temperature | -40°C~85°C |
| Packaging | Tube |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) |
| Number of Terminations | 8 |
| Voltage - Supply | 2.7V~5.5V |
| Pin Count | 8 |
| Data Rate (Max) | 400kHz |
| Capacitance - Input | 5.2pF |
| Current - Supply | 1mA |
| ROHS Status | ROHS3 Compliant |
Key Features
- Bidirectional buffer isolates capacitance and allows 400 pF on either side of the device.
- Supports offset-free hot-swap with IDLE/STOP detect circuitry.
- Voltage level translation from 0.9 V to 5.5 V and from 2.7 V to 5.5 V.
- Dual supply pins can be powered up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance.
- Undervoltage/initialization circuit holds the PCA9508 in a disconnected state during power-up, presenting high-impedance to all SDA and SCL pins.
- Active HIGH repeater enable input with an internal pull-up (100 kΩ).
Applications
The PCA9508D,118 is primarily used in I²C-bus and SMBus applications, particularly in scenarios where hot-swappable I/O cards are required. This includes:
- I²C - Hotswap applications.
- Systems requiring level shifting between different voltage domains.
- Bus extension and capacitance isolation in I²C-bus systems.
Q & A
- What is the primary function of the PCA9508D,118?
The PCA9508D,118 is a hot swappable level translating I²C-bus repeater that supports hot-swap with zero offset and provides level shifting between low and high voltage domains.
- What are the operating voltage ranges for the PCA9508D,118?
The device operates with supply voltages ranging from 2.7 V to 5.5 V and can translate levels from as low as 0.9 V.
- What is the maximum data rate supported by the PCA9508D,118?
The maximum data rate supported is 400 kHz.
- How does the PCA9508D,118 handle hot-swapping?
The device supports offset-free hot-swap with IDLE/STOP detect circuitry, ensuring that the data and clock buses are not corrupted during card insertion or removal.
- What is the package type of the PCA9508D,118?
The device is packaged in an 8-SOIC (0.154, 3.90mm Width) package.
- Is the PCA9508D,118 ROHS compliant?
Yes, the PCA9508D,118 is ROHS3 compliant.
- What is the maximum capacitance allowed on either side of the buffer?
The device allows up to 400 pF on either side of the buffer.
- How does the device handle power-up sequences?
The dual supply pins can be powered up in any sequence, and when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance.
- What is the purpose of the undervoltage/initialization circuit?
The undervoltage/initialization circuit holds the PCA9508 in a disconnected state during power-up, presenting high-impedance to all SDA and SCL pins.
- What is the role of the enable pin (EN) in the PCA9508D,118?
The active HIGH repeater enable input with an internal pull-up (100 kΩ) forces the part into the disconnected state when LOW and enables the repeater when HIGH.
