PCA9515ADT - 2-Channel 400kHz I2C Buffer | Texas Instruments
MPN: PCA9515ADT ✓ ActivePCA9515ADT Overview
An I2C repeater is an interface IC used to extend or segment a two-wire serial bus. I2C and SMBus systems connect controllers and peripherals through SDA and SCL, with pull-up resistors establishing the high logic level. Within the broader semiconductor hierarchy, a repeater belongs to the interface IC category and ultimately functions as a signal buffer and bus isolator. Adding a repeater can divide a long capacitive bus into shorter sections, reducing the load presented to the controller and improving signal integrity at Fast Mode speeds.
The PCA9515A family provides two bidirectional channels, I2C and SMBus compatibility, active-high enable control, open-drain I/O, and mixed-mode signal support. Its I2C input/output pins and enable input are specified as 5.5 V tolerant, allowing interface signals to exceed the device's 3.6 V maximum supply voltage under the stated conditions. The architecture also supports Standard Mode and Fast Mode devices, multiple masters, and powered-off high-impedance I2C pins.
The two identical channels make the PCA9515ADT useful for repeating both clock and data. Because the buffers are bidirectional, information can flow from either side of a channel through the same SDA or SCL path. The active-high enable input allows a host or reset controller to disconnect a repeated segment when isolation is required. TI identifies the device as a BiCMOS integrated circuit, combining bipolar and CMOS process characteristics in the same interface component.
Typical uses include extending an I2C sensor bus, segmenting a long point-to-point connection, isolating controller and peripheral buses, and supporting mixed-mode systems that include both Standard Mode and Fast Mode devices. The 400 kHz operating capability suits sensors, EEPROMs, expanders, real-time clocks, and other common low-speed I2C peripherals. It can also assist when bus capacitance prevents one controller from reliably driving every attached device directly.
Design the surrounding bus carefully because the repeater does not replace pull-up resistors or solve every signal-integrity problem. Place the device near the boundary between bus sections, provide the pull-ups required for each local segment, and confirm that enable control cannot float during power transitions. Review the manufacturer pin-description table when assigning PCB tracks and preserve adequate spacing from unrelated noisy circuitry.
This page organizes the device's key electrical characteristics, application guidance, verified drop-in alternatives, and practical integration considerations. It is intended to help engineers compare bus-extension options and implement the PCA9515ADT without overlooking enable-state, voltage-tolerance, or capacitance requirements.
Drop-in alternatives for PCA9515ADT — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PCA9515ADT (same form factor and footprint) — differing in Number of Channels, Package.
PCA9515ADR
✅ Drop-InContact for price
View Datasheet →PCA9515ADP
✅ Drop-In📋 Reference alternative (not in catalog)
PCA9515ADT Specifications
| Product Type | 2-channel bidirectional I2C bus and SMBus repeater |
| Number of Channels | 2 channels |
| Supply Voltage Range | 2.3 V to 3.6 V |
| Maximum I2C Bus Frequency | 400 kHz |
| I2C I/O Tolerance | 5.5 V tolerant |
| Enable Input Tolerance | 5.5 V tolerant |
| Enable Polarity | Active-high |
| I2C I/O Structure | Open-drain bidirectional |
| Supported Bus Modes | I2C and SMBus |
| Supported I2C Speeds | Standard Mode and Fast Mode |
| Multiple Master Support | Supported |
| Powered-Off I2C Pin Behavior | High impedance |
| Process Technology | BiCMOS |
| Package | 8-pin SOIC |
| Mounting Type | Surface mount |
| Operating Temperature Range | -40°C to 85°C |
| Lifecycle Status | Active |
PCA9515ADT 8-pin soic Pin Configuration Guide
Pin configuration for PCA9515ADT (8-pin soic package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for PCA9515ADT.
Refer to the datasheet for full pin configuration.
Typical Applications
PCA9515ADT is suitable for 6 applications: I2C Sensor Bus Extension, Industrial Control Bus Segmentation, EEPROM and RTC Bus Expansion, Mixed-Mode I2C System Support, Server and Storage Management Bus, Battery-Powered Sensor Node.
I2C Sensor Bus Extension
The PCA9515ADT fits between a host controller and a group of remote I2C sensors when capacitive loading makes one long bus difficult to drive reliably. Its two bidirectional open-drain channels repeat SDA and SCL at up to 400 kHz, reducing the load presented to the source controller by creating a separate downstream bus section. Each section needs its own correctly sized pull-up network, and the enable input should have a defined state during startup. Measurement of rise time and settling behavior is essential when cable or connector capacitance is substantial.
Recommended
Industrial Control Bus Segmentation
The PCA9515ADT can divide a densely populated industrial I2C bus into shorter electrical sections while retaining 400 kHz operation. Its two identical bidirectional channels accommodate both SDA and SCL without directional control signals, while the active-high enable input allows a controller to isolate a repeated segment during maintenance or reconfiguration. Industrial systems should account for pull-up placement, ground continuity, conducted noise, and cable capacitance. The 2.3 V to 3.6 V supply range also supports common 3.3 V control rails.
Recommended
EEPROM and RTC Bus Expansion
The PCA9515ADT is appropriate for placing EEPROMs, real-time clocks, and other low-speed I2C peripherals behind a controlled bus segment. Its 400 kHz maximum rate supports Fast Mode communication, while its bidirectional open-drain channels preserve normal SDA and SCL behavior. Because the repeater does not translate voltage levels, both sides must remain electrically compatible with the device's operating conditions. Place pull-ups on the relevant local sections and confirm that powered-off peripheral pins remain high impedance to avoid unintended bus contention.
Recommended
Mixed-Mode I2C System Support
The PCA9515ADT supports mixed-mode I2C systems containing Standard Mode and Fast Mode devices. Its active-high enable input gives the system controller an explicit way to connect or isolate a repeated channel, and its two identical bidirectional circuits simplify SDA/SCL implementation. Texas Instruments identifies multiple-master support and powered-off high-impedance behavior as important system features. Designers should still validate the slowest peripheral's bus timing and confirm that the enable state cannot conflict with an active controller during startup or reset.
Recommended
Server and Storage Management Bus
The PCA9515ADT can organize management, configuration, or sensor traffic on a server or storage platform when low-level I2C devices must communicate over longer board-level routes. The 400 kHz rate and dual-channel structure are appropriate for management-class peripherals rather than high-bandwidth data. Keeping the repeater near the boundary of the cable or board section helps contain capacitive loading. Validate signal integrity across connectors and ensure that no pulled-down powered-off peripheral can interfere with the high-impedance bus state.
Recommended
Battery-Powered Sensor Node
The PCA9515ADT can isolate a group of low-power sensors behind a bidirectional I2C repeater in a battery-operated node. Its 2.3 V to 3.6 V operating range supports common low-voltage sensor rails, while the active-high enable provides a control path for placing an unused segment in a high-impedance state. Power-conscious designs should confirm leakage and current behavior in the disabled state, account for pull-up losses, and use the enable control during sleep transitions to avoid unnecessary bus activity.
Recommended
Recommended Products Summary
Engineering reference data for PCA9515ADT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9515ADR | PCA9515ADP |
|---|---|---|---|
| Package | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC |
| Brand | Texas Instruments | Texas Instruments | NXP Semiconductors |
| Function | Dual bidirectional I2C/SMBus repeater | Dual bidirectional I2C/SMBus repeater | Dual bidirectional I2C/SMBus repeater |
| Number of Channels | 2 channels | 2 channels | 2 channels |
| Maximum Bus Frequency | 400 kHz | 400 kHz | 400 kHz |
Key Differentiators
- Maintains the established PCA9515A interface architecture (vs PCA9515ADP)
- Texas Instruments manufacturing and support continuity (vs PCA9515ADP)
- Tape-and-reel order format for automated assembly (vs PCA9515ADR)
- Active-high enable and 5.5 V-tolerant control input (vs PCA9515ADR)
Design Notes
Place the PCA9515ADT close to the physical boundary between the upstream and downstream I2C sections. Keep SDA and SCL traces short, route them as a coupled pair, and avoid sharing the section with unrelated high-current or high-speed signals. Provide local pull-up paths on the appropriate bus sections and verify that exposed-pad, thermal-pad, or other package-specific layout requirements in the manufacturer datasheet are followed when applicable.
Treat each side of the repeater as an electrically distinct bus segment. Select pull-up resistance from the local capacitance and required rise time rather than copying the value from an unrelated board. Measure SCL and SDA rise time at the far end of each segment, including connector and cable parasitics, and verify that the 400 kHz Fast Mode timing budget remains satisfied under the worst loading condition.
Do not use PCA9515ADT as a 3.3 V-to-5 V bidirectional level translator; its 5.5 V-tolerant I/O rating is not voltage translation. Also ensure the active-high enable input never floats and that all connected devices are high impedance when their bus section is disabled. Powered-off devices with active pull-down paths can prevent the repeated bus from reaching a valid high level even when the repeater is correctly configured.
The repeater's supply and pull-up arrangements influence the power budget even though the device does not continuously drive a logic high. Ensure that VCC remains within the 2.3 V to 3.6 V operating range and that the I2C pull-ups use the correct bus-side voltage. During power sequencing, prevent a peripheral on a disabled section from pulling SDA or SCL low while the controller expects the segment to be idle.
Compliance Information
The commercial interface IC is not presented as an automotive-qualified device. Specific environmental and material compliance declarations were not established for the exact orderable MPN.