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NXP Semiconductors PCA9518APW,518
- Part No.:
- PCA9518APW,518
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
PCA9518APW,518.pdf
- Description:
- IC INTERFACE SPECIALIZED 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,154
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Product details
Overview
PCA9518APW,518 from NXP Semiconductors is a 5-channel expandable I²C-bus hub repeater IC designed to extend I²C/SMBus systems beyond the 400 pF capacitance limit. It buffers both SDA and SCL lines across five bidirectional ports (SCL0–SCL4/SDA0–SDA4), supports 2.3 V to 3.6 V operation, tolerates 5 V on I²C and enable pins, and enables multi-master arbitration with clock stretching transparency. It is used in modular industrial control backplanes where bus segmentation and voltage-level interoperability (e.g., 3.3 V master ↔ 5 V slave segments) are required.
For engineers reviewing the PCA9518APW,518 datasheet, PCA9518APW,518 pinout, PCA9518APW,518 application, or PCA9518APW,518 equivalent, key selection criteria include per-port enable control (EN1–EN4), expansion bus compatibility (EXPSCL1/2, EXPSDA1/2), lock-up-free low-voltage threshold design, and dynamic propagation delays (tPHL ≤ 389 ns, tPLH ≤ 265 ns) under Fast-mode (400 kHz) conditions.
Technical Context
The PCA9518APW,518 implements a hub-based repeater architecture with five independent open-drain buffer pairs, each supporting standard- and fast-mode I²C timing (0–400 kHz). Its internal hysteresis logic uses differential input thresholds (VIL = 0.25VDD, VILc = 0.4VDD) and buffered LOW output (~0.52 V) to prevent inter-repeater lock-up during contention.
Expansion is enabled via four dedicated open-drain pins (EXPSCL1/2, EXPSDA1/2) that form a shared 4-wire cluster bus-allowing multiple PCA9518A devices to be grouped without direction pins. Port 0 is always active; EN1–EN4 individually enable ports 1–4, with internal pull-ups and 300 ns setup/hold timing relative to START/STOP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2.3 V to 3.6 V - Enables direct interface with 3.3 V logic while maintaining 5 V tolerance on I²C and enable pins. |
| I²C Clock Frequency | 0 Hz to 400 kHz - Supports full Fast-mode operation; system max frequency reduced by repeater delay (tPLH ≤ 265 ns). |
| Bus Ports | 5 bidirectional channels (SCL0/SDA0 to SCL4/SDA4) - Port 0 always active; ports 1–4 controlled by EN1–EN4. |
| Expansion Interface | 4-pin open-drain cluster bus (EXPSCL1/2, EXPSDA1/2) - Enables scalable hub topologies without external direction control. |
| Propagation Delay | tPHL ≤ 389 ns, tPLH ≤ 265 ns - Ensures timing compliance in multi-segment 400 kHz I²C systems with minimal added latency. |
| ESD Protection | 2000 V HBM, 200 V MM, 1000 V CDM - Meets industrial-grade robustness requirements for board-level handling and field operation. |
| Operating Temperature | −40 °C to +85 °C - Qualified for extended industrial ambient environments without derating. |
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 with thermal and mechanical reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EXPSCL1 (1) | Expansion serial clock input/output | Drives LOW when any local SCL falls below 0.3VDD; synchronizes cluster-wide clock transitions. |
| VDD (20) | Positive supply | 2.3–3.6 V main power; powers all internal buffers and logic; 5 V tolerant on other pins. |
| SCL0 (3), SDA0 (4) | Primary I²C bus interface | Always-active hub port; requires external pull-ups; connects to system master or backbone bus. |
| EN1–EN4 (7,11,14,17) | Active-HIGH channel enables | Individually gate ports 1–4; internal pull-ups allow wire-OR distributed control; must be stable during bus idle. |
| VSS (10) | Ground reference | System ground return for all internal circuitry and I/O drivers. |
Key Features
| Feature | Design Value |
|---|---|
| Expandable 5-channel hub | Enables unlimited bus segmentation using EXPxxxn pins-no direction pin needed, eliminating routing complexity in multi-hub clusters. |
| Lock-up free operation | Differential input thresholds (VILc − VOL = 70 mV guaranteed) prevent deadlocks between cascaded repeaters during arbitration. |
| Powered-off high-impedance I/O | I²C pins enter Hi-Z state when VDD < 2.0 V-prevents back-driving and allows safe hot-swap or partial power-down of subsystems. |
| 5 V tolerant I²C and enable pins | Eliminates level-shifting circuitry when interfacing 3.3 V hubs with 5 V slave peripherals or controllers. |
| Support for arbitration & clock stretching | Preserves I²C protocol integrity across segments-slave-initiated clock stretch propagates transparently to master. |
Applications
| Industrial Backplane Segmentation | Multi-Voltage I²C Interfacing |
|---|---|
Use Scenario: Modular PLC chassis with isolated I/O modules connected via segmented I²C buses. IC Role / Device Role / Timing Role: Hub repeater isolating capacitance between slots while preserving arbitration and clock stretching. Use Value: Enables >400 pF total bus load per segment; supports concurrent 400 kHz communication across 5+ slots without signal degradation. | Use Scenario: Microcontroller (3.3 V) managing legacy 5 V sensors and EEPROMs over shared I²C. IC Role / Device Role / Timing Role: Voltage-tolerant bus buffer enabling direct connection without external level shifters. Use Value: Reduces BOM count and layout area; eliminates timing skew introduced by discrete translators. |
| Scalable Sensor Hub Architecture | Distributed Enable-Controlled Subsystems |
Use Scenario: Smart building controller aggregating temperature, humidity, and occupancy data from geographically dispersed sensor nodes. IC Role / Device Role / Timing Role: Central hub connecting up to five independent sensor subnets, each with local master. Use Value: Allows independent subnet clocking (e.g., 100 kHz for slow sensors, 400 kHz for fast ADCs) while maintaining global addressability. | Use Scenario: Automotive body control module where sub-systems (lighting, HVAC, door locks) activate only on demand. IC Role / Device Role / Timing Role: Per-port enable (EN1–EN4) gating unused segments to reduce leakage and noise coupling. Use Value: Lowers static current draw; prevents spurious wakeups on inactive branches during sleep mode. |
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; no expansion pins; fixed dual-port topology; 2.7–5.5 V supply. | Not suitable for >2 segment expansion or hub clustering; lacks EN1–EN4 per-port control. | Select when only two isolated buses are needed and space/cost constraints preclude multi-channel solutions. |
| TCA9517PWR | 2-channel, 1.65–5.5 V; integrated 10 kΩ pull-ups; no expansion capability; lower propagation delay (tPLH ≤ 120 ns). | Designed for point-to-point isolation-not for multi-hub topologies; no support for EXPSCL/SDA clustering. | Prefer for compact, low-latency repeater links where scalability and multi-master coordination are not required. |
Compared with PCA9518APW,518, the PCA9517DP,118 and TCA9517PWR offer simpler dual-port buffering but lack expandable hub architecture, per-port enable control, and cluster synchronization-making them unsuitable for systems requiring >2 segments or coordinated multi-hub arbitration.
Availability
PCA9518APW,518 is available at Aetrix Electronics and suitable for industrial backplane segmentation, multi-voltage I²C interfacing, and scalable sensor hub architectures requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for PCA9518APW,518 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.
The PCA9518A belongs to NXP's I²C-bus repeater and hub product line, engineered specifically to solve bus capacitance limitations and voltage-level interoperability in complex, modular embedded systems.
FAQ
What is the maximum I²C clock frequency supported by the PCA9518APW,518?
The PCA9518APW,518 supports I²C clock frequencies from 0 Hz up to 400 kHz (Fast-mode). While the device itself operates within this range, the effective system frequency may be lower due to cumulative propagation delays-tPHL ≤ 389 ns and tPLH ≤ 265 ns per segment-as documented in the PCA9518APW,518 datasheet. Designers must verify timing margins in multi-hop configurations.
Does the PCA9518APW,518 require external pull-up resistors on its I²C bus lines?
Yes, the PCA9518APW,518 requires external pull-up resistors on all SCLx and SDAx lines-including SCL0/SDA0 and enabled ports-as it features open-drain outputs. Each bus segment must have its own pull-up network; resistor values depend on bus speed, capacitance, and voltage (e.g., ~2.2 kΩ for 400 kHz at 3.3 V). The PCA9518APW,518 does not integrate pull-ups.
Can multiple PCA9518APW,518 devices be connected in series (daisy-chained)?
No, the PCA9518APW,518 is not designed for series (daisy-chain) connection. It uses an expansion bus (EXPSCL1/2, EXPSDA1/2) for parallel hub clustering-not cascaded repeater chains. Connecting PCA9518APW,518 devices in series with PCA9515/16 or other PCA9518 clusters will cause recognition failure due to incompatible LOW-level voltage offsets. Only parallel expansion via EXP pins is supported.
What happens to the I²C pins of the PCA9518APW,518 when VDD is below 2.0 V?
When VDD drops below 2.0 V, the I²C-bus pins (SCLx, SDAx) of the PCA9518APW,518 automatically enter a high-impedance (Hi-Z) state-preventing back-powering or contention on powered-down segments. This behavior is intrinsic to the PCA9518APW,518's partial power-down design and ensures safe operation during brown-out or hot-swap events.
Is the PCA9518APW,518 pin-compatible with the PCA9518AD variant?
Yes, the PCA9518APW,518 (TSSOP20) and PCA9518AD (SO20) share identical pin functions and electrical specifications, differing only in package type and mechanical dimensions. Both use the same 20-pin assignment per the PCA9518A datasheet. Layouts must account for footprint differences-SOT360-1 vs. SOT163-1-but signal routing and enable logic remain fully interchangeable.
PCA9518APW,518 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- Buffer
- Interface:
- I2C, SMBus
- Voltage - Supply:
- 3V ~ 3.6V
- Supplier Device Package:
- 20-TSSOP
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
PCA9518APW,518 FAQ
1.How can I place an order for PCA9518APW,518 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9518APW,518 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 PCA9518APW,518 reliable?
The price and inventory of PCA9518APW,518 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9518APW,518 is usually 5 days.
3.What payment methods are accepted for PCA9518APW,518?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9518APW,518 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9518APW,518?
PCA9518APW,518 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9518APW,518 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 PCA9518APW,518?
For technical support, including PCA9518APW,518 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9518APW,518 requirements.
6.How does Aetrix verify that PCA9518APW,518 is sourced from the original manufacturer or authorized distributors?
All PCA9518APW,518 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 PCA9518APW,518 meets industry standards.
7.What is the process for return or replacement of PCA9518APW,518?
All PCA9518APW,518 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9518APW,518, 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 PCA9518APW,518 part is unused and in its original packaging.
Return procedure for PCA9518APW,518:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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