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NXP Semiconductors PCA9518APW,512
- Part No.:
- PCA9518APW,512
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
PCA9518APW,512.pdf
- Description:
- IC INTERFACE SPECIALIZED 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,205
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Product details
Overview
PCA9518APW,512 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 Standard- and Fast-mode (up to 400 kHz), operates from 2.3 V to 3.6 V, and features 5 V-tolerant I/O pins. It enables multi-segment bus architectures with lock-up-free arbitration and clock stretching transparency in industrial sensor networks and modular embedded systems.
For engineers reviewing the PCA9518APW,512 datasheet, PCA9518APW,512 pinout, PCA9518APW,512 application, or PCA9518APW,512 equivalent, this device serves as a scalable, voltage-flexible I²C repeater for high-density bus segmentation-particularly where mixed-voltage (3.3 V/5 V) slave domains, distributed enable control, and expansion-cluster scalability are required.
Technical Context
The PCA9518APW,512 implements a five-port, open-drain, bidirectional buffer architecture with dedicated expansion pins (EXPSCL1/2, EXPSDA1/2) enabling multi-hub clustering without direction pins. Its internal hysteresis-based thresholding (VILc = 0.4 V, VOL = 0.52 V typical) prevents lock-up by using offset low-level propagation between segments.
It supports full I²C protocol integrity-including arbitration, clock stretching, and multi-master operation-across all five ports. Each port (except port 0) has an active-HIGH enable input (EN1–EN4) with internal pull-ups, allowing per-channel isolation while maintaining global bus coherence via expansion bus signaling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2.3 V to 3.6 V - Enables interoperability with 3.3 V logic domains and partial power-down behavior below 2.0 V. |
| I²C Clock Frequency | 0 Hz to 400 kHz - Supports Fast-mode I²C devices; system max frequency reduced by repeater delay (~265 ns typical tPLH). |
| Bus Ports | 5 bidirectional channels (SCL0/SDA0 through SCL4/SDA4) - Port 0 always active; ports 1–4 individually enabled via EN1–EN4. |
| I/O Voltage Tolerance | 5 V tolerant on SDA/SCL and enable pins - Eliminates level-shifting circuitry when interfacing with 5 V slaves or masters. |
| Expansion Interface | 4-pin open-drain expansion bus (EXPSCL1/2, EXPSDA1/2) - Enables daisy-chained clusters of multiple PCA9518A devices with no external direction control. |
| Low-Level Output Voltage | VOL = 0.52 V (typical at 6 mA) - Ensures reliable LOW-level recognition across segments while preventing contention lock-up via VOL−VILc ≥ 70 mV margin. |
| ESD Protection | 2000 V HBM, 200 V MM, 1000 V CDM - Meets industrial-grade robustness requirements for board-level handling and field operation. |
Pinout & Package
TSSOP20 package (SOT360-1): 20-lead plastic thin shrink small outline, 4.4 mm body width, 0.65 mm pitch, lead-free compatible.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (EXPSCL1) | Expansion serial clock input/output | Drives LOW when any local SCL falls below 0.3×VDD; synchronizes cluster-wide clock state. |
| 2 (EXPSCL2) | Expansion serial clock input/output | Drives LOW when any local SCL ≤ 0.4×VDD; provides secondary timing reference for rising-edge coordination. |
| 3 (SCL0) | Primary I²C clock bus | Always-enabled hub port; connects to system master or backbone bus; requires external pull-up. |
| 4 (SDA0) | Primary I²C data bus | Always-enabled hub port; carries bidirectional data; requires external pull-up; no enable pin. |
| 5–6 (SCL1/SDA1) | Secondary I²C bus pair | Port 1 channel; enabled only when EN1 = HIGH; isolated during EN1 = LOW. |
| 7 (EN1) | Active-HIGH enable input | Internally pulled up; controls SCL1/SDA1 drivers; must be stable during bus idle to avoid arbitration failure. |
| 8–9 (SCL2/SDA2) | Tertiary I²C bus pair | Port 2 channel; enabled only when EN2 = HIGH; electrically isolated when disabled. |
| 10 (VSS) | Ground reference | System ground return for all internal logic and I/O buffers; must be low-impedance. |
| 11 (EN2) | Active-HIGH enable input | Controls SCL2/SDA2; supports distributed enable via wire-OR with other open-drain signals. |
| 12–13 (SCL3/SDA3) | Quaternary I²C bus pair | Port 3 channel; enabled only when EN3 = HIGH; shares same expansion bus timing as other ports. |
| 14 (EN3) | Active-HIGH enable input | Controls SCL3/SDA3; allows selective activation of subsystems without reconfiguring hardware. |
| 15–16 (SCL4/SDA4) | Quinary I²C bus pair | Port 4 channel; enabled only when EN4 = HIGH; completes full 5-port hub capability. |
| 17 (EN4) | Active-HIGH enable input | Final port enable; permits dynamic segmentation-e.g., isolating legacy 100 kHz slaves from 400 kHz domains. |
| 18 (EXPSDA1) | Expansion serial data input/output | Drives LOW when any local SDA falls below 0.3×VDD; coordinates data-line state across hubs. |
| 19 (EXPSDA2) | Expansion serial data input/output | Drives LOW when any local SDA ≤ 0.4×VDD; resolves final-rising-edge priority in multi-hub clusters. |
| 20 (VDD) | Power supply | 2.3 V–3.6 V supply; powers all buffers and logic; powers I/O even when downstream buses are unpowered. |
Key Features
| Feature | Design Value |
|---|---|
| Expandable 5-channel hub | Enables unlimited bus segmentation via EXPxxxn pins-no direction pin required, simplifying multi-device cluster routing. |
| Lock-up free operation | Uses differential thresholding (VILc = 0.4 V, VOL = 0.52 V) to prevent deadlocks during inter-port LOW propagation. |
| Powered-off high-impedance I/O | I²C pins enter Hi-Z when VDD < 2.0 V-prevents backfeeding and allows safe hot-swap or partial power-down scenarios. |
| 5 V tolerant I²C and enable pins | Eliminates external level shifters in mixed-voltage systems (e.g., 3.3 V master ↔ 5 V sensors), reducing BOM count and layout area. |
| Individual active-HIGH enables | EN1–EN4 allow per-port activation/deactivation-enabling dynamic bandwidth allocation and fault containment in modular systems. |
| Supports arbitration & clock stretching | Preserves I²C protocol semantics end-to-end-ensures multi-master coexistence and slave-driven clock hold functionality across segments. |
Applications
| Industrial Sensor Network | Modular PLC Backplane |
|---|---|
|
Use Scenario: A central controller communicates with 20+ distributed temperature, pressure, and humidity sensors across long cable runs, exceeding 400 pF total bus capacitance. IC Role / Device Role / Timing Role: PCA9518APW,512 acts as a segmented repeater hub-partitioning sensors into five isolated 4-node sub-buses, each staying within 400 pF limit while sharing one master interface. Use Value: Enables deterministic 400 kHz communication without signal degradation; eliminates need for custom capacitive loading compensation or additional microcontrollers per segment. |
Use Scenario: A programmable logic controller uses interchangeable I/O modules (analog input, digital output, encoder interface), each with its own I²C-configurable parameters and calibration data. IC Role / Device Role / Timing Role: PCA9518APW,512 serves as a hot-pluggable module interface hub-each port assigned to one module type, with ENn pins controlled by FPGA to isolate faulty or unconfigured modules. Use Value: Provides electrical isolation between modules, prevents bus lock-up during insertion/removal, and maintains master visibility of all present modules via shared SCL0/SDA0. |
| Mixed-Voltage Automotive Body Control | Server Rack Management Bus |
|
Use Scenario: A 3.3 V MCU manages legacy 5 V lighting controllers, HVAC actuators, and door-lock modules over a single I²C infrastructure. IC Role / Device Role / Timing Role: PCA9518APW,512 functions as a voltage-transparent repeater-connecting the 3.3 V master bus to four independent 5 V slave domains via SCL1–SCL4/SDA1–SDA4. Use Value: Removes requirement for discrete level translators per slave group; supports simultaneous 100 kHz (legacy) and 400 kHz (new) devices on same physical bus topology. |
Use Scenario: A rack-mounted server motherboard monitors 12+ hot-swap power supplies, fans, and DIMM thermal sensors using SMBus, with strict noise and isolation requirements. IC Role / Device Role / Timing Role: PCA9518APW,512 operates as a noise-isolated SMBus repeater-assigning each PSU/fan group to a dedicated port, with ENn pins tied to supervisor GPIOs for fault-triggered isolation. Use Value: Prevents single-point failures from collapsing entire management bus; reduces crosstalk between high-noise power domains and sensitive analog sensor lines. |
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, SO14 package, 2.7–5.5 V supply, no expansion pins, fixed dual-port architecture. | Limited to two isolated segments; lacks clustering capability and individual port enables; simpler for basic point-to-point extension. | Select PCA9517DP,118 when only two bus segments are needed and expansion scalability is unnecessary. |
| TCA9517PWR | 2-channel repeater, TSSOP14, 1.65–5.5 V supply, integrated 10 kΩ pull-ups, no expansion interface, lower quiescent current (1.5 µA). | Optimized for ultra-low-power battery-backed systems; lacks per-port enables and expansion bus; not suitable for >2 segment topologies. | Choose TCA9517PWR for space-constrained, low-quiescent designs with only two bus domains and no future expansion needs. |
Compared with PCA9517DP,118 and TCA9517PWR, the PCA9518APW,512 uniquely delivers five independently controllable ports plus expansion-capable clustering-making it the only option among the three for scalable, multi-hub I²C infrastructure in modular industrial or telecom equipment.
Availability
PCA9518APW,512 is available at Aetrix Electronics and suitable for industrial sensor networks, modular PLC backplanes, and mixed-voltage automotive body control systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCA9518APW,512 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 deep expertise in interface, power, and security ICs.
The PCA9518APW,512 belongs to NXP's I²C-bus repeater and hub product line, engineered specifically for scalable, robust, and voltage-flexible bus extension in high-reliability embedded systems where protocol integrity and segmentation control are critical.
FAQ
What is the maximum supported I²C clock frequency for PCA9518APW,512?
The PCA9518APW,512 supports Fast-mode I²C operation up to 400 kHz. However, actual system frequency may be lower due to cumulative propagation delays-tPLH is 259 ns (typical), and tPHL is 202 ns (typical). For reliable 400 kHz operation, ensure total bus capacitance per segment remains ≤400 pF and use appropriate pull-up resistors per side of the repeater. The PCA9518APW,512 preserves clock stretching and arbitration timing across all five ports.
Does PCA9518APW,512 require external pull-up resistors on all I²C bus lines?
Yes, external pull-up resistors are mandatory on every SCL and SDA line-including SCL0/SDA0 and all enabled SCLn/SDAn ports-as well as on all four expansion pins (EXPSCL1/2, EXPSDA1/2). The PCA9518APW,512 contains no internal pull-ups on I²C or expansion lines. Pull-up values depend on bus speed and capacitance; typical values range from 1.1 kΩ (I²C) to 500 Ω (EXPxxxn). Port 0 requires pull-ups even when unused, since it has no enable pin.
Can PCA9518APW,512 be used in series with PCA9515 or PCA9516 devices?
No, a PCA9518APW,512 cluster cannot be placed in series with PCA9515/PCA9516 devices or another PCA9518A cluster not connected via EXPxxxn pins. This is due to incompatible LOW-level voltage thresholds: the PCA9518APW,512 outputs a "buffered LOW" (~0.52 V), which falls outside the valid VIL range of PCA9515/PCA9516 (≤0.25×VDD). Interoperability is only guaranteed within PCA9518A clusters linked by their dedicated expansion bus.
How does PCA9518APW,512 handle power loss on one segment?
When VDD drops below 2.0 V, the PCA9518APW,512 places all I²C-bus I/O pins (SCLn/SDAn) into high-impedance state-preventing backfeeding and ensuring electrical isolation. Expansion pins (EXPSCL1/2, EXPSDA1/2) also go Hi-Z. This behavior allows safe partial power-down of subsystems without disrupting other active segments. The PCA9518APW,512 resumes normal operation once VDD rises above 2.3 V.
What is the purpose of the EXPSCL1/EXPSCL2 and EXPSDA1/EXPSDA2 pins on PCA9518APW,512?
These four expansion pins form a dedicated open-drain bus that synchronizes LOW-level transitions across multiple PCA9518APW,512 devices in a cluster. EXPSCL1/EXPSDA1 respond to falling edges below 0.3×VDD; EXPSCL2/EXPSDA2 respond to levels ≤0.4×VDD. This dual-threshold scheme resolves timing priority during rising edges-ensuring only the last SCL/SDA line to rise drives the cluster-wide transition, eliminating race conditions. They enable seamless, pin-defined clustering without external direction logic.
PCA9518APW,512 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
PCA9518APW,512 FAQ
1.How can I place an order for PCA9518APW,512 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9518APW,512 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,512 reliable?
The price and inventory of PCA9518APW,512 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9518APW,512 is usually 5 days.
3.What payment methods are accepted for PCA9518APW,512?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9518APW,512 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9518APW,512?
PCA9518APW,512 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9518APW,512 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,512?
For technical support, including PCA9518APW,512 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9518APW,512 requirements.
6.How does Aetrix verify that PCA9518APW,512 is sourced from the original manufacturer or authorized distributors?
All PCA9518APW,512 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,512 meets industry standards.
7.What is the process for return or replacement of PCA9518APW,512?
All PCA9518APW,512 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9518APW,512, 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,512 part is unused and in its original packaging.
Return procedure for PCA9518APW,512:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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