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Home > Products > Integrated Circuits (ICs) > Interface > Signal Buffers, Repeaters, Splitters

NXP Semiconductors PCA9511D,112

Name: PCA9511D,112
Brand: NXP Semiconductors
SKU: PCA9511D,112
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PCA9511D,112

Manufacturer:: NXP Semiconductors

Category:: Signal Buffers, Repeaters, Splitters

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: PCA9511D,112.pdf

Description:: IC BUFFER I2C/SMBUS HOTSWAP 8SO

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Product details

Overview

PCA9511D,112 from NXP Semiconductors (formerly Philips) is a hot-swappable I²C and SMBus bus buffer IC designed for live insertion of I/O cards into multi-point backplane systems. It provides bi-directional buffering between backplane and card SDA/SCL lines, isolates capacitances up to 10 pF on the backplane side, supports 0–400 kHz clock frequency, operates from 2.7 V to 5.5 V, and features rise time accelerator circuitry with 0.6 V threshold for improved signal integrity in high-capacitance environments - deployed in CompactPCI, VME, and AdvancedTCA systems.

For engineers reviewing the PCA9511D,112 datasheet, PCA9511D,112 pinout, PCA9511D,112 application, or PCA9511D,112 equivalent, key selection considerations include its 8-pin SO package, ENABLE-controlled low-current mode (<200 µA), READY open-drain status flag, 1 V precharge on all SDA/SCL pins, and differential offset voltage ≤150 mV under 3.3 V operation - critical for reliable hot-swap sequencing and bus contention avoidance.

Technical Context

The PCA9511D,112 implements a dual-stage connection control architecture: an under-voltage lockout (UVLO) and bus-idle detection circuit enforces a minimum 130 µs initialization delay before enabling backplane-to-card connectivity only after STOP or bus idle is detected. Its rise time accelerator activates at 0.6 V on rising edges, sourcing up to 2 mA transient pull-up current to meet I²C fast-mode rise-time requirements despite weak external pull-ups.

Signal propagation uses slew-rate-dependent bidirectional coupling: falling edges below 0.7 V_CC trigger internal pull-down drivers with controlled slew rate (≥1.25 V/µs), while rising edges above 0.6 V engage the accelerator. The device maintains high-impedance SDA/SCL pins when V_CC = 0 V and supports clock stretching and multi-master arbitration without disruption.

Key Specifications

Parameter	Value and Actual Design Meaning
Operating Voltage	2.7 V to 5.5 V - enables interoperability across 3.3 V and 5 V I²C/SMBus domains without level-shifting components.
Max Clock Frequency	400 kHz - fully supports I²C Fast Mode and SMBus 1.1 timing requirements.
Rise Time Accelerator Threshold	0.6 V - triggers 2 mA boost current precisely to meet 300 ns rise-time limit under 100 pF load.
Input-Output Offset Voltage	≤150 mV at 3.3 V - ensures logic-level compatibility across buffered sides with minimal voltage shift.
Bus Idle Detection Time	50–250 µs - guarantees safe connection only after stable bus quiescence, preventing data corruption during hot insertion.
ENABLE Shutdown Current	≤200 µA - reduces system standby power when card is inactive or unpowered.
SDA/SCL Precharge Voltage	1.0 V ±0.2 V - minimizes inrush current and voltage overshoot during mechanical mating of live backplane connectors.

Pinout & Package

PCA9511D,112 is housed in an 8-pin plastic small outline (SO8) package per drawing SOT96-1, 3.9 mm body width, surface-mount compatible, with standard JEDEC MS-012AC footprint.

Pin/Terminal	Circuit Role	Design Meaning
1 - ENABLE	Digital enable input	Active-HIGH control: asserts connection sequence when HIGH; forces <200 µA shutdown and disables accelerators when LOW.
2 - SCLOUT	Card-side SCL bidirectional terminal	Connects to card's SCL bus; electrically isolated from backplane until READY goes HIGH.
3 - SCLIN	Backplane-side SCL bidirectional terminal	Interfaces directly to backplane SCL; monitored for STOP/idle to initiate safe connection.
4 - GND	Ground reference	Must connect to low-impedance ground plane to ensure noise immunity and proper UVLO operation.
5 - READY	Open-drain status output	Pulls LOW during initialization or ENABLE=LOW; goes HIGH (with external 10 kΩ pull-up) only when SDA/SCL paths are fully connected.
6 - SDAIN	Backplane-side SDA bidirectional terminal	Monitored alongside SCLIN for bus idle; precharged to 1 V during insertion to suppress transients.
7 - SDAOUT	Card-side SDA bidirectional terminal	Drives card's SDA bus; mirrors SDAIN state once connection is established with ≤150 mV offset.
8 - VCC	Power supply input	Supplies internal circuitry; powers precharge, accelerators, and READY driver; tolerant to 5.5 V max.

Key Features

Feature	Design Value
Rise time accelerator on all SDA/SCL lines	2 mA transient current activated above 0.6 V enables compliant rise times even with 16 kΩ pull-ups on 5 V buses.
1 V precharge on all SDA/SCL pins	Reduces worst-case insertion current by >80% versus unprecharged interfaces, eliminating glitches during connector mating.
High-impedance SDA/SCL pins at VCC = 0 V	Prevents backfeeding and latch-up during power sequencing or card removal under partial power loss.
READY open-drain output with 3 mA sink capability	Provides unambiguous hardware handshake to system controller indicating full electrical connection readiness.
Bi-directional buffering with <10 pF backplane loading	Isolates card capacitance from backplane, allowing scalable multi-card architectures without cumulative bus timing violations.

Applications

CompactPCI Hot-Swap Card Interface	VME Backplane Expansion
Use Scenario: Inserting a peripheral I/O card into a powered CompactPCI chassis while maintaining uninterrupted communication with other modules. IC Role / Device Role / Timing Role: PCA9511D,112 acts as a hot-swap bus buffer between backplane and card, enforcing safe connection only after bus idle detection and providing rise-time acceleration to maintain 400 kHz timing margins. Use Value: Eliminates SDA/SCL bus corruption during insertion, reduces required pull-up strength by 2×, and enables deterministic READY signaling for system firmware coordination.	Use Scenario: Adding sensor or actuator interface cards to an operational VME-based industrial control rack without powering down the entire system. IC Role / Device Role / Timing Role: PCA9511D,112 serves as a capacitance-isolating repeater, decoupling card-side parasitic loads from the main backplane bus and accelerating rising edges on both SDA and SCL. Use Value: Maintains I²C signal integrity across long VME traces, prevents timing violations due to cumulative bus capacitance, and supports legacy 5 V and modern 3.3 V mixed-voltage designs.
AdvancedTCA Shelf Management	I²C Bus Extender for Long-Distance Links
Use Scenario: Enabling hot-plug capability for AdvancedTCA shelf manager cards that monitor power, cooling, and FRU status via I²C. IC Role / Device Role / Timing Role: PCA9511D,112 buffers the management bus between shelf controller and field-replaceable units, using 1 V precharge and ENABLE-controlled sequencing to prevent bus lockup during FRU replacement. Use Value: Guarantees zero-downtime maintenance, meets PICMG 3.0 hot-swap timing requirements, and simplifies FRU design by offloading bus isolation to a single integrated component.	Use Scenario: Extending I²C communication beyond 1 meter between a host controller and remote sensor node in factory automation. IC Role / Device Role / Timing Role: PCA9511D,112 functions as a repeater, isolating master and slave segments and applying rise-time acceleration to compensate for RC delays in long PCB traces or cables. Use Value: Enables reliable 400 kHz operation over 2000 pF total bus capacitance, eliminates need for active repeaters or custom ASICs, and maintains full I²C protocol transparency including clock stretching.

CompactPCI Hot-Swap Card Interface

VME Backplane Expansion

Use Scenario: Inserting a peripheral I/O card into a powered CompactPCI chassis while maintaining uninterrupted communication with other modules.

IC Role / Device Role / Timing Role: PCA9511D,112 acts as a hot-swap bus buffer between backplane and card, enforcing safe connection only after bus idle detection and providing rise-time acceleration to maintain 400 kHz timing margins.

Use Value: Eliminates SDA/SCL bus corruption during insertion, reduces required pull-up strength by 2×, and enables deterministic READY signaling for system firmware coordination.

Use Scenario: Adding sensor or actuator interface cards to an operational VME-based industrial control rack without powering down the entire system.

IC Role / Device Role / Timing Role: PCA9511D,112 serves as a capacitance-isolating repeater, decoupling card-side parasitic loads from the main backplane bus and accelerating rising edges on both SDA and SCL.

Use Value: Maintains I²C signal integrity across long VME traces, prevents timing violations due to cumulative bus capacitance, and supports legacy 5 V and modern 3.3 V mixed-voltage designs.

AdvancedTCA Shelf Management

I²C Bus Extender for Long-Distance Links

Use Scenario: Enabling hot-plug capability for AdvancedTCA shelf manager cards that monitor power, cooling, and FRU status via I²C.

IC Role / Device Role / Timing Role: PCA9511D,112 buffers the management bus between shelf controller and field-replaceable units, using 1 V precharge and ENABLE-controlled sequencing to prevent bus lockup during FRU replacement.

Use Value: Guarantees zero-downtime maintenance, meets PICMG 3.0 hot-swap timing requirements, and simplifies FRU design by offloading bus isolation to a single integrated component.

Use Scenario: Extending I²C communication beyond 1 meter between a host controller and remote sensor node in factory automation.

IC Role / Device Role / Timing Role: PCA9511D,112 functions as a repeater, isolating master and slave segments and applying rise-time acceleration to compensate for RC delays in long PCB traces or cables.

Use Value: Enables reliable 400 kHz operation over 2000 pF total bus capacitance, eliminates need for active repeaters or custom ASICs, and maintains full I²C protocol transparency including clock stretching.

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C bus buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
PCA9510D,112	No rise time accelerator circuitry; lacks 2 mA boost current and 0.6 V activation threshold.	Suitable for systems with strong external pull-ups or lower bus capacitance where rise-time acceleration is unnecessary.	Select PCA9510D,112 only if bus rise time is already compliant without acceleration and interference from multiple accelerators must be avoided.
TCA9511PWR	TI variant with identical pinout, same 0.6 V accelerator threshold, but rated for –40°C to +125°C and includes enhanced ESD protection (±8 kV HBM).	Required for extended temperature industrial or automotive applications where PCA9511D,112's +85°C max ambient is insufficient.	Choose TCA9511PWR when operating beyond 85°C ambient or when higher ESD robustness is mandated by system-level EMC requirements.

Compared with PCA9510D,112, the PCA9511D,112 delivers guaranteed rise-time compliance in high-capacitance backplanes via its 2 mA accelerator; versus TCA9511PWR, it offers cost-optimized commercial-temperature support but lacks extended thermal and ESD ratings - making PCA9511D,112 ideal for standard industrial backplane hot-swap where cost and footprint are prioritized.

Availability

PCA9511D,112 is available at Aetrix Electronics and suitable for CompactPCI, VME, and AdvancedTCA system integration requiring stable component supply, long-term lifecycle assurance, and verified hot-swap reliability in multi-card backplane architectures.

Supply support for PCA9511D,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 leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep heritage in I²C interface IP originating from Philips.

The PCA9511D,112 belongs to NXP's legacy I²C bus buffer product line, engineered specifically to solve hot-swap signal integrity challenges in modular computing backplanes - emphasizing deterministic connection sequencing, capacitance isolation, and rise-time acceleration for robust multi-drop I²C/SMBus operation.

FAQ

What is the function of the READY pin on the PCA9511D,112?

The READY pin on the PCA9511D,112 is an open-drain output that signals when the internal connection circuitry has completed initialization and safely connected the backplane SDA/SCL lines to the card-side terminals. It remains LOW during power-up, ENABLE=LOW, or bus idle detection; it transitions HIGH only after tEN (130 µs) and tIDLE (50–250 µs) have elapsed with no activity. For PCA9511D,112 designs, this pin must be pulled up externally with a 10 kΩ resistor to VCC to generate a valid logic HIGH indicating ready-to-operate status.

Does the PCA9511D,112 support I²C clock stretching and multi-master arbitration?

Yes, the PCA9511D,112 fully supports I²C clock stretching and multi-master arbitration. Its bidirectional buffering preserves the open-drain nature of SDA and SCL lines, allowing any device on either side to hold the line LOW to stretch the clock or participate in arbitration. The internal connection circuitry does not insert latency or alter signal polarity, ensuring transparent protocol compliance - a confirmed feature explicitly stated in the PCA9511D,112 datasheet under "Features" and validated in its block diagram and timing diagrams.

What is the purpose of the 1 V precharge on SDA and SCL pins in the PCA9511D,112?

The 1 V precharge on all SDA and SCL pins of the PCA9511D,112 minimizes transient current and voltage disturbance during mechanical insertion of a live card into a powered backplane. By pulling pins to 1.0 V ±0.2 V via internal 100 kΩ resistors during initialization, it reduces worst-case inrush when backplane and card pins are at opposite logic states. This precharge is active only during startup and deactivates upon connection - a design-specific behavior confirmed for PCA9511D,112 in the "Operation" section and Figure 5 block diagram.

Can the PCA9511D,112 operate with different supply voltages on the backplane and card sides?

No, the PCA9511D,112 has a single VCC pin and does not support disparate supply voltages on backplane and card sides. Both sides share the same VCC domain (2.7 V to 5.5 V), and level translation is not provided. For systems requiring 5 V backplane to 3.3 V card interfacing, the PCA9514 or PCA9515 - which feature dual VCC pins - are specified alternatives. The PCA9511D,112 datasheet explicitly limits operation to one supply rail, and Figures 10–11 confirm its use only in same-VCC configurations unless external level shifters are added.

What is the maximum bus capacitance the PCA9511D,112 can drive while maintaining 400 kHz operation?

The PCA9511D,112 itself presents <10 pF loading to the backplane, but the maximum total bus capacitance it can support at 400 kHz depends on pull-up strength and rise-time acceleration. With its 2 mA rise-time accelerator enabled, the PCA9511D,112 allows use of weaker pull-ups (up to 24 kΩ at 5.5 V, 16 kΩ at 3.6 V) while still meeting 300 ns rise-time limits - effectively supporting ≥400 pF total bus capacitance per side when combined with appropriate resistor selection per Figures 6 and 7. This capability is quantified in the "Resistor Pull-up Value Selection" section and confirmed by the 400 kHz fSCL_SDA specification.

PCA9511D,112 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Type:: Buffer, Accelerator

Applications:: I2C - Hotswap

Input:: 2-Wire Bus

Output:: 2-Wire Bus

Data Rate (Max):: 400kHz

Number of Channels:: 1

Delay Time:: -

Signal Conditioning:: -

Capacitance - Input:: 5 pF

Voltage - Supply:: 2.7V ~ 5.5V

Current - Supply:: 6mA

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SO

PCA9511D,112 FAQ

1.How can I place an order for PCA9511D,112 through Aetrix?

Please submit a Request for Quotation (RFQ) for PCA9511D,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 PCA9511D,112 reliable?

The price and inventory of PCA9511D,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9511D,112 is usually 5 days.

3.What payment methods are accepted for PCA9511D,112?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9511D,112 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PCA9511D,112?

PCA9511D,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PCA9511D,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 PCA9511D,112?

For technical support, including PCA9511D,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9511D,112 requirements.

6.How does Aetrix verify that PCA9511D,112 is sourced from the original manufacturer or authorized distributors?

All PCA9511D,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 PCA9511D,112 meets industry standards.

7.What is the process for return or replacement of PCA9511D,112?

All PCA9511D,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9511D,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 PCA9511D,112 part is unused and in its original packaging.

Return procedure for PCA9511D,112:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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