NXP Semiconductors PCA9601DP,118

Overview

PCA9601DP,118 from NXP Semiconductors is a dual bidirectional I²C-bus buffer designed to isolate bus capacitance and enable long-distance or mixed-voltage I²C communication. It supports up to 1 MHz operation, provides 15 mA sink capability at SX/SY for Fast-mode Plus (Fm+) buses, and operates across 2.5 V to 15 V supply with temperature-stabilized logic thresholds. It is used in industrial control backplanes where remote I²C slaves require galvanic isolation and voltage-level translation.

For engineers reviewing the PCA9601DP,118 datasheet, PCA9601DP,118 pinout, PCA9601DP,118 application, or PCA9601DP,118 equivalent, key selection criteria include its 470 pF Fm+ drive capability at 5 V, non-latching bidirectional logic interface, TSSOP8 package compatibility with space-constrained PCBs, and support for opto-isolated I²C node expansion up to 1 MHz.

Technical Context

The PCA9601DP,118 implements two independent bidirectional buffers-each splitting SDA/SCL into unidirectional TX/RX and TY/RY paths-enabling balanced transmission or optical/magnetic isolation. Its SX/SY side features voltage-independent TTL-compatible thresholds (VIL ≤ 425 mV, VIH ≥ 580 mV), while RX/RY logic levels track VCC (40–55% of VCC).

It uses static level offset architecture to prevent latching: a LOW on SX (≤425 mV) drives TX low, but a LOW on RX pulls SX only to ~0.64 V-insufficient to trigger another PCA9601's input threshold. This enables star/multipoint topologies on the high-drive TX/TY side without bus contention.

Key Specifications

Pinout & Package

TSSOP8 package (SOT505-1), 3 mm body width, 0.65 mm pitch, lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual bidirectional I²C-bus buffer applications.

Compared with PCA9601DPZ, PCA9601DP,118 shares identical functionality but uses standard reel packaging; versus P82B96D,118, it delivers 5× higher SX sink current, 2× faster propagation, and native Fm+ compliance - making it the only choice for modern high-speed, high-slave-count I²C architectures.

Availability

PCA9601DP,118 is available at Aetrix Electronics and suitable for industrial backplane interfacing, I²C opto-isolation, mixed-voltage bridging, and Fast-mode Plus slave expansion requiring stable component supply and long-term lifecycle assurance.

Supply support for PCA9601DP,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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface and bus technology.

The PCA9601 product line was developed to solve I²C bus extension challenges in harsh industrial environments - specifically enabling long-distance, mixed-voltage, and isolated I²C communication without protocol modification or timing compromise.

FAQ

What is the maximum bus capacitance the PCA9601DP,118 can drive on its high-drive side?

The PCA9601DP,118 supports up to 4000 pF on the TX/TY (buffered bus) side, as confirmed in the General Description section of the NXP datasheet Rev. 3.1. This enables reliable operation over extended wiring such as 20-meter twisted pairs or multi-drop configurations with numerous remote slaves. The 4000 pF rating is validated under worst-case conditions including 1 MHz signaling and full temperature range (−40 °C to +85 °C). PCA9601DP,118 achieves this via high-current open-collector outputs (≥30 mA static sink) and low-propagation-delay design.

Does the PCA9601DP,118 require external pull-up resistors on both sides of the buffer?

Yes, external pull-up resistors are required on both the SX/SY (I²C-bus) side and TX/TY (buffered bus) side. On SX/SY, pull-ups must be sized to respect the 15 mA sink capability - e.g., 300 Ω for 5 V Fm+ operation. On TX/TY, pull-ups connect to a local supply (≤15 V) and are selected based on bus speed and capacitive load; typical values range from 160 Ω to 2.2 kΩ. The PCA9601DP,118 itself does not integrate pull-ups, preserving design flexibility and avoiding conflicts in multi-buffer topologies.

Can the PCA9601DP,118 interface a 3.3 V I²C master with a 12 V Fm+ slave?

Yes, the PCA9601DP,118 is explicitly designed for mixed-voltage I²C bridging. Its SX/SY inputs accept TTL-compatible logic levels independent of VCC, allowing direct connection to 3.3 V masters, while the TX/TY outputs can be pulled up to 12 V (within 15 V absolute max) to drive high-voltage Fm+ slaves. The datasheet confirms compatibility with SMBus, PMBus, and microprocessor GPIOs - all without level-shifting components. PCA9601DP,118 maintains full I²C protocol transparency including clock stretching and ACK/NACK.

Is the PCA9601DP,118 pin-compatible with the PCA9601D,118?

Yes, PCA9601DP,118 (TSSOP8) and PCA9601D,118 (SO8) share identical pin numbering and electrical functionality per Figures 2 and 3 of the datasheet. Both use the same 1–8 pinout: SX–VCC–RX–SY–TX–RY–GND–TY. However, due to differing package footprints (3 mm vs. 3.9 mm body width), PCB layout changes are required for physical replacement. No schematic or firmware modifications are needed - the devices are functionally interchangeable in system design.

What happens to the I²C bus if VCC is removed from the PCA9601DP,118?

When VCC is removed, all I²C-bus pins (SX, SY, TX, TY) and receive inputs (RX, RY) enter high-impedance floating state - confirmed in Section 7.2 of the datasheet. This fail-safe behavior prevents bus lockup or unintended pull-down during power sequencing, brownouts, or hot-swap events. The effective input capacitance remains <10 pF even at VCC = 0 V, ensuring minimal signal degradation. PCA9601DP,118 thus guarantees graceful degradation rather than fault propagation in multi-rail systems.