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NXP Semiconductors PCA9518PW,112
- Part No.:
- PCA9518PW,112
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
PCA9518PW,112.pdf
- Description:
- IC INTERFACE SPECIALIZED 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,964
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Product details
Overview
PCA9518PW,112 from NXP Semiconductors is a 5-channel bidirectional I²C-bus repeater hub designed to extend I²C/SMBus systems beyond the 400 pF capacitance limit. It buffers both SDA and SCL lines across five independent ports (SCL0–SCL4/SDA0–SDA4), supports Standard- and Fast-mode (up to 400 kHz), operates from 3.0 V to 3.6 V, and features 5 V–tolerant I/O pins. It enables scalable multi-segment bus architectures in industrial control and modular embedded systems.
For engineers reviewing the PCA9518PW,112 datasheet, PCA9518PW,112 pinout, PCA9518PW,112 application, or PCA9518PW,112 equivalent, this device delivers expandable buffering with active HIGH individual enable inputs (EN1–EN4), lock-up–free operation via differential expansion signaling (EXPSCL1/2, EXPSDA1/2), and powered-off high-impedance I²C pins - critical for hot-swap-capable backplane and distributed sensor network designs.
Technical Context
The PCA9518PW,112 implements a BiCMOS 5-port hub architecture with open-drain input/output buffers per channel, supporting arbitration and clock stretching transparently across segments. Its expansion interface uses four dedicated open-drain pins (EXPSCL1/2, EXPSDA1/2) to coordinate state propagation between cascaded devices without direction control pins.
It employs voltage-offset hysteresis (VOL ≈ 0.52 V, VILc = 0.4 V) to prevent inter-repeater lock-up: a "regular LOW" at input triggers a "buffered LOW" (~0.5 V) at outputs, which is only recognized by other PCA9518 devices - not by PCA9515/16 or legacy repeaters - ensuring cluster-isolated signal integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bus Channels | 5 bidirectional I²C ports (SCL0–SCL4 / SDA0–SDA4), each independently enabled |
| Max Clock Frequency | 400 kHz Fast-mode - supports mixed Standard- (100 kHz) and Fast-mode devices on same hub |
| Supply Voltage | 3.0 V to 3.6 V - stable operation across industrial 3.3 V rail tolerances |
| I/O Voltage Tolerance | 5 V tolerant on all I²C and enable pins - eliminates level-shifter need in mixed-voltage systems |
| Propagation Delay | tPHL = 105–389 ns (HIGH→LOW), tPLH = 110–265 ns (LOW→HIGH) - single-repeater latency for deterministic timing budgets |
| Expansion Interface | 4-wire open-drain EXP bus (EXPSCL1/2, EXPSDA1/2) - enables arbitrary-size clusters without external logic |
| ESD Robustness | 2000 V HBM, 200 V MM, 1000 V CDM - suitable for handling in uncontrolled assembly environments |
Pinout & Package
TSSOP20 package (SOT360-1): plastic thin shrink small outline, 20 leads, 4.4 mm body width, 0.65 mm pitch - optimized for high-density PCB layouts.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (EXPSCL1) | Expansion serial clock 1 | Open-drain output driven LOW when any local SCL falls below 0.3×VCC - synchronizes cluster-wide clock transitions |
| 2 (EXPSCL2) | Expansion serial clock 2 | Open-drain output driven LOW when any local SCL ≤ 0.4 V - provides hysteresis margin to avoid metastability |
| 3 (SCL0) | Port 0 serial clock | Always-active I²C clock line - no enable pin; requires external pull-up regardless of cluster configuration |
| 4 (SDA0) | Port 0 serial data | Always-active I²C data line - must be pulled up externally; serves as root bus interface in hub topology |
| 7 (EN1) | Port 1 enable | Active HIGH input with internal pull-up - disables SCL1/SDA1 I/O and isolates port 1 when LOW |
| 10 (GND) | Supply ground | Reference for all I/O and internal logic - must be low-impedance connection to minimize noise coupling |
| 17 (EN4) | Port 4 enable | Active HIGH input - controls SCL4/SDA4; allows dynamic segmentation of 5-port hub into 1–4 active channels |
| 18 (EXPSDA1) | Expansion serial data 1 | Open-drain output driven LOW when any local SDA falls below 0.3×VCC - coordinates data-line arbitration across hubs |
| 19 (EXPSDA2) | Expansion serial data 2 | Open-drain output driven LOW when any local SDA ≤ 0.4 V - ensures robust low-level detection during contention |
| 20 (VCC) | Supply voltage | 3.0–3.6 V power input - powers all buffers and hub logic; decoupling capacitor required within 10 mm |
Key Features
| Feature | Design Value |
|---|---|
| Expandable 5-channel hub | Enables unlimited bus segmentation using EXPxxxn pins - no external glue logic needed for multi-hub clusters |
| Lock-up free operation | Differential threshold design (VOL − VILc = 70 mV) prevents deadlocks between repeaters in same cluster |
| Powered-off high-impedance I/O | I²C pins enter Hi-Z when VCC < 2.0 V - supports safe insertion/removal in live backplanes |
| 5 V tolerant I/O | Allows direct interfacing between 3.3 V masters and 5 V slaves without external level shifters |
| Individual port enable | Four active HIGH EN pins (EN1–EN4) permit dynamic channel isolation - essential for fault containment |
Applications
| Industrial Sensor Networks | Modular PLC Backplanes |
|---|---|
Use Scenario: Distributed temperature, pressure, and flow sensors deployed across multiple mechanical zones connect to a central controller via daisy-chained I²C segments. IC Role / Device Role / Timing Role: PCA9518PW,112 acts as segment repeater and voltage translator, isolating capacitance per zone while enabling 5 V sensor nodes to communicate with 3.3 V controller. Use Value: Eliminates bus collapse due to cumulative trace + node capacitance (>400 pF), maintains 400 kHz throughput across 5+ segments, and simplifies wiring by removing discrete level shifters. |
Use Scenario: Programmable Logic Controller chassis with hot-swappable I/O modules requires isolated I²C communication between CPU slot and peripheral slots. IC Role / Device Role / Timing Role: PCA9518PW,112 serves as backplane hub, providing per-module enable control (EN1–EN4) and powered-off Hi-Z during module insertion/removal. Use Value: Prevents bus contention during hot-swap events, guarantees arbitration integrity across slots, and enables firmware-controlled activation of specific I/O banks. |
| Automotive Body Control Modules | Medical Diagnostic Equipment |
Use Scenario: Door module, seat control, and lighting subsystems communicate over shared I²C backbone with varying voltage domains (5 V sensors, 3.3 V microcontrollers). IC Role / Device Role / Timing Role: PCA9518PW,112 functions as voltage-agile repeater hub, buffering SCL/SDA between domains while preserving SMBus compliance. Use Value: Reduces BOM count by replacing discrete translators and repeaters; meets automotive ESD requirements (2000 V HBM) without added protection circuitry. |
Use Scenario: Multi-probe diagnostic system integrates analog front-ends, EEPROM calibration data, and display controllers on segmented I²C buses to avoid signal integrity degradation. IC Role / Device Role / Timing Role: PCA9518PW,112 operates as low-latency repeater (tPHL < 389 ns), ensuring real-time response for time-critical calibration reads and status updates. Use Value: Maintains sub-microsecond timing margins required for synchronized probe sampling, avoids clock stretching artifacts in clinical data streams. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C-bus repeater applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9517DP,118 | 2-channel repeater (vs. 5-channel); no expansion pins; fixed dual-port topology | Suitable only for simple point-to-point bus extension - cannot form multi-hub clusters | Select when only two isolated segments are needed and board space is constrained |
| TCA9517PWR | 2-channel repeater with auto-direction sensing; no expansion capability; 1.65–5.5 V supply range | Lacks ENn pins and EXP interface - no per-port enable or cluster scalability | Prefer for ultra-low-voltage (1.8 V) systems where PCA9518PW,112's 3.0 V min is incompatible |
Compared with PCA9517DP,118 and TCA9517PWR, the PCA9518PW,112 uniquely supports scalable multi-hub topologies via EXPxxxn pins and offers per-port enable control - making it the only option for systems requiring >2 segments, dynamic channel disable, or mixed-voltage domain coordination without external logic.
Availability
PCA9518PW,112 is available at Aetrix Electronics and suitable for industrial sensor networks, modular PLC backplanes, automotive body control modules, and medical diagnostic equipment requiring stable component supply and long-term obsolescence management.
Supply support for PCA9518PW,112 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 company specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with leadership in interface, power management, and embedded processing technologies.
The PCA9518PW,112 belongs to NXP's I²C-bus repeater and hub product line, engineered specifically to solve bus capacitance limitations and voltage-domain interoperability in distributed embedded systems.
FAQ
What is the minimum supply voltage required for reliable operation of the PCA9518PW,112?
The PCA9518PW,112 requires a minimum supply voltage of 3.0 V for guaranteed specification compliance across its full operating temperature range (−40 °C to +85 °C). Below 3.0 V, VOL, VIH, and propagation delays may deviate from datasheet limits; operation below 2.0 V places I²C pins in high-impedance state but disables functional repeater behavior. Always maintain VCC ≥ 3.0 V in active use cases for the PCA9518PW,112.
Can the PCA9518PW,112 be used in series with a PCA9515 or PCA9516 repeater?
No, the PCA9518PW,112 must not be placed in series with PCA9515 or PCA9516 devices. Its buffered LOW output (~0.52 V) falls outside the VILc (≤0.4 V) recognition window of those older repeaters, causing signal dropout and bus lock-up. The PCA9518PW,112 is only compatible with other PCA9518 devices via the EXPxxxn expansion interface - never in daisy-chain configurations with non-PCA9518 repeaters.
How does the PCA9518PW,112 handle I²C arbitration across buffered segments?
Each PCA9518PW,112 buffer preserves I²C arbitration transparency: SDA/SCL contention is detected locally, and the expansion bus (EXPSDA1/2, EXPSCL1/2) propagates state changes with controlled hysteresis to synchronize arbitration outcomes across all ports. This ensures that multi-master arbitration resolves identically on all segments - no arbitration loss or false ACK/NACK occurs due to repeater latency in the PCA9518PW,112.
What pull-up resistor values are recommended for the PCA9518PW,112's I²C ports?
Per NXP Application Note AN255, each side of every PCA9518PW,112 buffer (local and remote) requires independent pull-up resistors. For 3.3 V systems at 400 kHz, 1.1 kΩ is typical; for 100 kHz or higher bus capacitance, values down to 800 Ω may be used. Expansion pins (EXPSCL1/2, EXPSDA1/2) require 500 Ω pull-ups per the datasheet test conditions - critical for correct cluster timing in the PCA9518PW,112.
Is the PCA9518PW,112 pin-compatible with the SO20-packaged PCA9518D?
Yes, the PCA9518PW,112 (TSSOP20, SOT360-1) shares identical pin numbering, function mapping, and electrical specifications with the PCA9518D (SO20, SOT163-1). Both packages use the same 20-pin layout shown in Figures 3 and 4 of the datasheet. Mechanical footprint differs, but schematic symbol and netlist connectivity are fully interchangeable - enabling drop-in replacement where board space allows the smaller TSSOP20 body.
PCA9518PW,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Applications:
- Buffer
- Interface:
- I2C, SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Supplier Device Package:
- 20-TSSOP
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
PCA9518PW,112 FAQ
1.How can I place an order for PCA9518PW,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9518PW,112 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PCA9518PW,112 reliable?
The price and inventory of PCA9518PW,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9518PW,112 is usually 5 days.
3.What payment methods are accepted for PCA9518PW,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9518PW,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9518PW,112?
PCA9518PW,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9518PW,112 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PCA9518PW,112?
For technical support, including PCA9518PW,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9518PW,112 requirements.
6.How does Aetrix verify that PCA9518PW,112 is sourced from the original manufacturer or authorized distributors?
All PCA9518PW,112 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PCA9518PW,112 meets industry standards.
7.What is the process for return or replacement of PCA9518PW,112?
All PCA9518PW,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9518PW,112, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PCA9518PW,112 part is unused and in its original packaging.
Return procedure for PCA9518PW,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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