NXP Semiconductors PCA9517ADP,118

Overview

PCA9517ADP,118 from NXP Semiconductors is a bidirectional I²C-bus repeater IC enabling voltage-level translation between 0.9 V (port A) and 2.7–5.5 V (port B) domains while isolating bus capacitance up to 400 pF per side. It supports Standard- and Fast-mode I²C (up to 400 kHz), features active-HIGH enable control, and maintains arbitration and clock stretching transparency across the repeater. It is used in mixed-voltage embedded systems such as multi-rail sensor hubs and low-power microcontroller interfaces.

For engineers reviewing the PCA9517ADP,118 datasheet, PCA9517ADP,118 pinout, PCA9517ADP,118 application, or PCA9517ADP,118 equivalent, key selection criteria include port-specific supply ranges (VCC(A): 0.9–5.5 V; VCC(B): 2.7–5.5 V), lock-up-free open-drain buffering, ESD robustness (>5.5 kV HBM), and TSSOP8 package compatibility with 0.65 mm pitch layouts.

Technical Context

The PCA9517ADP,118 implements dual independent open-drain buffers with asymmetric input thresholds: port A recognizes LOW at ≤0.3×VCC(A) to support sub-1 V logic, while port B uses a 0.43 V threshold with 70 mV hysteresis to prevent false triggering during contention. Its internal power-good circuit requires VCC(A) > 0.8 V and VCC(B) > 2.5 V before driver activation.

Propagation delays are directionally asymmetric: port A→B tPHL is 60–230 ns (typ. 79 ns), while port B→A tPHL is 10–110 ns (typ. 80 ns at VCC(A) ≥3 V). The EN pin has an internal pull-up to VCC(B) and must only toggle during bus-idle states to avoid protocol lock-up.

Key Specifications

Pinout & Package

TSSOP8 package (SOT505-1), 3 mm body width, 0.65 mm lead pitch, thermally enhanced for industrial ambient (−40 °C to +85 °C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C-bus repeater applications.

Compared with PCA9515ADP,118, PCA9517ADP,118 adds 0.9 V operation and 2.75× higher ESD rating; versus TCA9517APWR, it shares identical electrical behavior but differs in qualification scope and manufacturer logistics - both alternatives require no PCB changes if footprint matches TSSOP8.

Availability

PCA9517ADP,118 is available at Aetrix Electronics and suitable for industrial sensor hubs, low-power MCU interfaces, hot-swap module backplanes, and multi-rail automotive body controllers requiring stable component supply across long product lifecycles.

Supply support for PCA9517ADP,118 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with core expertise in interface, power management, and embedded processing technologies.

The PCA9517A product line delivers robust, standards-compliant I²C-bus repeaters designed specifically for voltage-domain bridging and bus segmentation in resource-constrained embedded systems.

FAQ

What is the minimum operating voltage on port A of the PCA9517ADP,118?

The PCA9517ADP,118 supports port A operation down to 0.9 V, with guaranteed LOW-level detection at ≤0.3×VCC(A). At VCC(A) = 0.9 V, this corresponds to a maximum input LOW threshold of 270 mV - enabling direct interface with advanced ultra-low-power microcontrollers and sensors that operate at sub-1 V supply rails. This specification is validated across the full −40 °C to +85 °C temperature range.

Can the PCA9517ADP,118 be used with a 5 V master and a 1.2 V slave without external components?

Yes, the PCA9517ADP,118 enables direct 5 V ↔ 1.2 V I²C translation without external MOSFETs or resistive dividers. Configure port B for 5 V (VCC(B) = 5 V) and port A for 1.2 V (VCC(A) = 1.2 V); the device's asymmetric thresholds (0.3×VCC(A) = 360 mV on port A, 0.43 V on port B) and 5 V-tolerant I/Os ensure reliable bidirectional signaling. Pull-up resistors must be placed on both sides per I²C specification.

Does the PCA9517ADP,118 support clock stretching and multi-master arbitration?

Yes, the PCA9517ADP,118 fully preserves I²C protocol integrity: clock stretching initiated by any slave propagates transparently from port A to port B and vice versa, and arbitration resolution between competing masters occurs correctly across the repeater. This is achieved through synchronous open-drain buffering with no added latching or timing distortion - confirmed in NXP's application note AN255 and functional testing per I²C-bus specification UM10204.

What happens to the PCA9517ADP,118 I/O pins when VCC(A) or VCC(B) is unpowered?

When either VCC(A) or VCC(B) is at 0 V, all I/O pins (SDAA, SCLA, SDAB, SCLB) remain high-impedance and 5 V tolerant - no current flows into or out of the pins, preventing back-powering or latch-up. The EN pin retains its internal pull-up to VCC(B), so if only VCC(B) is present, EN remains HIGH and drivers activate only when VCC(A) rises above 0.8 V. This behavior is explicitly characterized in the "Powered-off high-impedance I²C-bus pins" feature.

Is the PCA9517ADP,118 pin-compatible with the older PCA9517D part?

No, the PCA9517ADP,118 is not pin-compatible with the obsolete PCA9517D. While both use TSSOP8 packaging, the PCA9517A introduced revised internal logic and improved ESD structure (>5.5 kV vs. >2 kV HBM), and the PCA9517D was discontinued years ago. NXP explicitly recommends migrating all new designs to PCA9517A variants like PCA9517ADP,118 due to superior robustness and extended voltage range - no mechanical or electrical drop-in replacement exists for the legacy part.