NXP Semiconductors PCA9617ATPZ

Overview

PCA9617ATPZ from NXP Semiconductors is a bidirectional, level-translating I²C-bus repeater IC enabling voltage translation between 0.8 V–5.5 V (Port A) and 2.2 V–5.5 V (Port B) domains while supporting Fast-mode Plus (1 MHz) operation. It provides capacitance isolation (540 pF per side at 1 MHz), open-drain buffering for SDA/SCL lines, and active HIGH enable referenced to VCC(B). It is used in mixed-voltage embedded systems such as multi-rail sensor hubs interfacing 1.2 V microcontrollers with 3.3 V peripherals.

For engineers reviewing the PCA9617ATPZ datasheet, PCA9617ATPZ pinout, PCA9617ATPZ application, or PCA9617ATPZ equivalent, key selection criteria include its dual-supply level-shifting capability, latching-free operation, static offset handling on Port B, 0.35×VCC(A) input threshold for ultra-low-voltage logic compatibility, and HWSON8 package thermal performance.

Technical Context

The PCA9617ATPZ implements two independent, bidirectional open-drain buffers with asymmetric voltage referencing: Port A uses a 0.35×VCC(A) input threshold and hard LOW output, optimized for sub-1 V logic; Port B employs a static offset design with 0.45 V input threshold and ~0.55 V VOL, enabling interoperability with standard 2.5/3.3/5 V I²C devices. Its power-up sequencing requires VCC(B) > 2.2 V and VCC(A) > 0.8 V before driver activation, with internal reference settling (~400 μs) independent of VCC(A) ramp order.

EN pin control is strictly synchronized to bus idle states to prevent arbitration corruption; disabling mid-cycle halts communication, while enabling mid-cycle causes protocol confusion. The device supports clock stretching and arbitration transparency across both ports, and includes overvoltage tolerance (5.5 V) on all I/Os-even when unpowered-ensuring robustness during hot-swap or partial-power scenarios.

Key Specifications

Pinout & Package

PCA9617ATPZ is housed in an 8-terminal HWSON8 (SOT1069-2) package: 2.0 mm × 3.0 mm × 0.75 mm body with exposed thermal pad, optimized for high-density PCB layouts and thermal dissipation in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C level translating repeater applications.

Compared with PCA9617ATPZ, TCA9617RTER offers comparable voltage flexibility but tighter EN threshold constraints and slower worst-case propagation, while PCA9517ADP sacrifices low-voltage capability and speed for cost-sensitive legacy designs - making PCA9617ATPZ the sole option for 0.8 V–1 MHz mixed-rail I²C extension.

Availability

PCA9617ATPZ is available at Aetrix Electronics and suitable for industrial sensor hubs, automotive body control modules, server baseboard management, and medical wearable subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for PCA9617ATPZ 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 power management ICs.

The PCA9617A product line was designed specifically to solve mixed-voltage I²C system challenges - enabling seamless integration of next-generation ultra-low-power peripherals with legacy or higher-voltage controllers without compromising timing, robustness, or layout simplicity.

FAQ

What is the minimum operating voltage for Port A of the PCA9617ATPZ?

The PCA9617ATPZ supports Port A supply voltages as low as 0.8 V, with guaranteed functionality down to this level when paired with VCC(B) ≥ 2.2 V and satisfying the constraint 0.4×VCC(A) + 0.8 V ≤ VCC(B). At VCC(A) = 0.95 V, the input threshold remains at 0.35×VCC(A) ≈ 0.33 V, enabling reliable interface with sub-1 V logic families. This makes PCA9617ATPZ uniquely suited for ultra-low-power applications where other I²C repeaters fail to operate.

Can PCA9617ATPZ be used with only one supply voltage powered?

No - PCA9617ATPZ requires both VCC(A) > 0.8 V and VCC(B) > 2.2 V to activate internal drivers. However, all I/O pins (SDAA, SCLA, SDAB, SCLB, EN) remain 5.5 V tolerant and high-impedance when either supply is unpowered, preventing back-drive or damage. This allows safe insertion into live buses and supports partial-power system states, but active level translation only occurs when both supplies meet their minimum thresholds. The PCA9617ATPZ power-up circuit enforces this sequencing requirement.

How does the PCA9617ATPZ prevent latching during level translation?

The PCA9617ATPZ avoids latching through deliberate asymmetry: Port B's input threshold (VIL = 0.4 V) is set ~90 mV below its output LOW voltage (VOL ≈ 0.55 V), so a driven LOW on Port B is not recognized as a valid LOW input by the internal comparator. Similarly, Port A's hard LOW output and 0.35×VCC(A) threshold ensure clean transitions. This design eliminates feedback-induced oscillation or stuck states - a known issue in simpler resistor-based or MOSFET-level shifters - and is verified across -40 °C to +85 °C.

Is the PCA9617ATPZ compatible with SMBus and PMBus protocols?

Yes - the PCA9617ATPZ explicitly supports Standard-mode, Fast-mode, Fast-mode Plus I²C-bus, SMBus (standard and high-power modes), and PMBus. Its open-drain architecture, arbitration transparency, clock stretching preservation, and 0.4 V VIL on Port B meet SMBus 2.0/3.0 electrical requirements. The device passes JEDEC JESD78 latch-up testing (>100 mA) and exceeds JESD22-A114 HBM (5500 V) and CDM (1000 V) ESD standards, fulfilling robustness requirements for SMBus-compliant systems.

What is the thermal pad requirement for the HWSON8 package of PCA9617ATPZ?

The HWSON8 package of PCA9617ATPZ features an exposed thermal pad that must be soldered to a corresponding copper thermal pad on the PCB using standard reflow profiles. Thermal vias are required beneath the pad to conduct heat into inner layers or ground planes. Failure to solder the pad degrades thermal resistance by >50 %, risks junction overheating above 125 °C under sustained 2.9 mA port B supply current, and compromises long-term reliability. The pad is electrically connected to GND internally, so the PCB thermal pad must be grounded.