PCA9518PW - Expandable 5-Channel I2C Hub | NXP
Référence : PCA9518PW ✓ ActifPCA9518PW Présentation
The PCA9518 is a type of I2C bus buffer, a specialized interface IC within the broader I2C interface and semiconductor hierarchy. Its primary function is to extend or segment an I2C bus by providing five buffered downstream channels and a separate upstream channel. This allows a controller to communicate with more peripherals than the electrical limitations of a direct bus connection would permit, while helping isolate capacitive loading and improve signal integrity in multi-device systems. The expandable architecture supports systems where additional downstream buses can be added as peripheral count and board complexity increase.
Key electrical characteristics include a 2.3 V to 3.6 V operating-supply range, partial power-down support, and operation in systems using either I2C or SMBus signaling. The high-impedance bus-pin behavior below 2.0 V is especially useful when a system must prevent unintended bus activity during shutdown, reset, or partial power sequencing. The 20-pin TSSOP package provides a surface-mount form factor suitable for industrial control, embedded instrumentation, communications equipment, and consumer-accessory designs.
The device is used as a bus hub rather than as a power regulator or level translator. A typical implementation places the PCA9518PW between the host I2C controller and a group of downstream peripherals. Each downstream channel can serve a separate device group, helping distribute bus capacitance and provide a controlled interface boundary. Designers must still verify pull-up resistor placement, voltage compatibility, channel-loading conditions, and the power-state behavior of every connected device.
For applications requiring more than five downstream channels, multiple PCA9518 hubs can be arranged in an expandable topology. This makes the part useful in modular industrial and test systems where a controller must support multiple removable or distributed peripheral groups. The 2.3 V to 3.6 V supply range also aligns it with common low-voltage digital systems, although every connected I2C device must support the same signaling voltage and compatible electrical limits.
A key design consideration is preserving the high-impedance behavior during partial power-down. The bus pins should not be externally forced when VDD falls below 2.0 V, because doing so can compromise the intended isolation behavior. PCB layout should keep the hub close to the controller or branch point, follow the datasheet’s recommended decoupling and pull-up arrangements, and avoid long unprotected branches that increase capacitance and reduce rise-time margin. Engineers should confirm the final bus timing and voltage levels with the complete peripheral population.
This product page combines verified manufacturer information, distributor identification, package data, and engineering-oriented selection guidance. It also distinguishes the confirmed PCA9518PW attributes from alternatives that require independent pinout and parameter verification rather than presenting them as automatic replacements.
Alternatives de remplacement direct pour PCA9518PW — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec PCA9518PW (même facteur de forme et même empreinte) — différant par Package, Product Type, Bus Compatibility, Bus Protocol, Function.
PCA9518AD,118
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
PCA9560PW,118
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
PCA9561PW,118
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
P82B96PWR
✅ Remplacement directContactez-nous pour le prix
Voir la fiche technique →P82B96DR
✅ Remplacement directContactez-nous pour le prix
Voir la fiche technique →PCA9518PW Spécifications
| Product Type | Expandable 5-channel I2C-bus hub |
| Interface | I2C and SMBus |
| Process Technology | BiCMOS |
| Supply Voltage Range | 2.3 V to 3.6 V |
| Downstream Channels | 5 channels |
| Bus Communication Frequency | 400 kHz |
| Partial Power-Down Input Threshold | VDD below 2.0 V |
| Partial Power-Down Bus Behavior | I2C-bus I/O pins remain high impedance |
| Boîtier | 20-pin TSSOP |
| Type de montage | Surface Mount |
| Manufacturer | NXP Semiconductors |
| Fonction | I2C bus buffering and expansion |
| Type de sortie | Push-pull |
| Operating Voltage | 2.3 V to 3.6 V |
| Partial Power-Down Support | Yes |
| I2C Bus Isolation | High-impedance state during partial power-down |
| Bus Protocol | I2C / SMBus |
| Statut RoHS | unknown |
| REACH Status | unknown |
Guide de configuration des broches du PCA9518PW 20-pin tssop
Configuration des broches du PCA9518PW (boîtier 20-pin tssop). La numérotation des broches, les fonctions et les schémas de connexion sont définis dans la fiche technique du fabricant. Consultez-la pour l'empreinte exacte et les directives de soudage.
Aucune donnée de brochage détaillée disponible pour PCA9518PW.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
PCA9518PW convient pour 6 applications: Industrial Control Bus Expansion, Test and Measurement Equipment, Communications Equipment, Embedded Data Acquisition, Server and Storage Management, Consumer Accessory Connectivity.
Industrial Control Bus Expansion
The PCA9518PW fits industrial control systems where a central controller must reach multiple peripheral groups over an I2C or SMBus connection. Its five downstream channels divide the bus into manageable branches, while the 2.3 V to 3.6 V supply range suits low-voltage digital control hardware. During partial power-down, the I/O pins remain high impedance below 2.0 V, helping prevent a partially powered hub from disturbing other bus nodes. The main design checks are operating-temperature qualification, pull-up placement, branch capacitance, and industrial EMI requirements, which are not fully specified in the supplied data.
Recommandé
Test and Measurement Equipment
The PCA9518PW can organize control and data peripherals in modular test equipment where multiple I2C devices share a controller. Five downstream channels allow instrumentation groups to be placed behind buffered branches, reducing the load presented by a single combined bus. The device’s 400 kHz bus capability aligns with conventional low-speed control buses, while partial-power-down behavior supports staged shutdown of test modules. Designers should account for cable-induced capacitance, isolate long branches where appropriate, and verify timing with the complete peripheral population rather than assuming identical rise times on every channel.
Recommandé
Communications Equipment
The PCA9518PW is useful in communications equipment that combines several low-speed I2C management devices with a common host controller. The upstream path and five downstream branches provide a structured way to connect transceivers, supervisory circuits, and configuration components. Its 2.3 V to 3.6 V operating range is compatible with common 3.3 V logic systems, and the high-impedance bus-pin behavior during partial power-down helps maintain bus availability during controlled shutdown. Final sign-off should verify signal levels, pull-up values, bus timing, and system-specific EMC and temperature requirements.
Recommandé
Embedded Data Acquisition
The PCA9518PW can divide sensors and data-acquisition peripherals into multiple downstream I2C groups. This arrangement is helpful when a controller must support several converters, amplifiers, or acquisition front ends and the combined capacitive loading would make a single segment difficult. The 5-channel structure provides additional routing flexibility, while the partial-power-down mode can keep unused branches electrically inactive below 2.0 V. Engineers should use the manufacturer application guidance for pull-ups and decoupling, calculate worst-case bus timing at 400 kHz, and confirm that every attached device remains compatible with the selected supply voltage.
Recommandé
Server and Storage Management
The PCA9518PW can provide a controlled I2C fan-out point in server or storage systems that include multiple management peripherals. By placing devices behind separate downstream channels, the hub can reduce loading on the management controller and organize peripherals by subsystem. The 2.3 V to 3.6 V supply range supports low-voltage management rails, and high-impedance behavior during partial power-down helps avoid unintended bus contention. In a server design, however, the engineer must verify hot-swap behavior, fault isolation, capacitance, pull-up topology, and the system-specific temperature and reliability requirements not supplied here.
Recommandé
Consumer Accessory Connectivity
The PCA9518PW can expand I2C connectivity in compact consumer accessories that combine sensors, configuration EEPROMs, and low-power interface devices. Its 20-pin TSSOP package supports space-conscious surface-mount layouts, and the five downstream channels provide more branch options than a direct controller connection. The 2.3 V to 3.6 V operating range is compatible with many 3.3 V portable-device rails, although battery-current limits and shutdown sequencing must be evaluated carefully. The partial-power-down feature can help prevent a partly powered hub from loading the system bus, provided external components do not defeat the high-impedance state.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour PCA9518PW — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | PCA9518AD,118 | PCA9560PW,118 | PCA9561PW,118 | P82B96PWR | P82B96DR |
|---|---|---|---|---|---|---|
| Package | 20-pin TSSOP | 20-pin TSSOP | 20-pin TSSOP | 20-pin TSSOP | 20-pin TSSOP | 20-pin SOIC |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
Principaux différenciateurs
- Five independently routed downstream I2C channels (vs PCA9560PW,118)
- Improved partial power-down behavior (vs P82B96PWR)
- Wider verified low-voltage operating range (vs PCA9561PW,118)
Notes de conception
Treat the partial-power-down behavior as a system-level constraint, not merely a device feature. NXP states that the I2C I/O pins remain high impedance when VDD is below 2.0 V. External pull-ups, level translators, or downstream devices must not force those pins during shutdown. Review the complete power tree so every bus node can become inactive without back-feeding the hub.
Follow the official NXP datasheet layout and component-placement guidance when assigning the PCA9518PW. Place the device near the branch point, keep the upstream and downstream routes short, and reserve local supply decoupling close to VDD and ground. Pull-up resistor placement should follow the chosen bus-topology strategy because placing every pull-up at the controller can produce different rise-time behavior from distributed branch placement.
Validate the complete I2C network at the intended 400 kHz operating point and with the highest expected peripheral loading. The five downstream channels provide physical separation, but they do not eliminate capacitance, leakage, or timing effects from long PCB routes and cables. Check rise time, pull-up resistance, sink current, and worst-case channel loading, especially when modules are connected through long harnesses.
Do not infer pin compatibility from the PCA95-family name or from a 20-pin package count alone. The verified results mention PCA9518AD,118, PCA9560PW,118, PCA9561PW,118, P82B96PWR, and P82B96DR, but complete official pinouts and parameter tables were not supplied. Compare every connected pin, supply range, channel function, enable state, and power-down behavior before approving a substitution.
Informations de conformité
The supplied search results reference RoHS and REACH comparison fields but do not provide the underlying compliance declarations for PCA9518PW. AEC-Q100 is not applicable because the device is an interface IC rather than an automotive-qualified power device; no automotive qualification claim was provided.
