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NXP Semiconductors PCA9517D,118
- Part No.:
- PCA9517D,118
- Manufacturer:
- NXP Semiconductors
- Category:
- Signal Buffers, Repeaters, Splitters
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
PCA9517D,118.pdf
- Description:
- IC REDRIVER I2C 1CH 400KHZ 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,660
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Product details
Overview
The PCA9517D,118 from NXP Semiconductors is a bidirectional I²C-bus repeater IC enabling voltage level translation between 0.9 V–5.5 V (A-side) and 2.7 V–5.5 V (B-side), supporting Standard- and Fast-mode I²C (up to 400 kHz), SMBus compatibility, and 400 pF bus capacitance isolation per side - deployed in mixed-voltage embedded systems such as multi-rail sensor hubs and low-power microcontroller peripherals.
For engineers reviewing the PCA9517D,118 datasheet, PCA9517D,118 pinout, PCA9517D,118 application, or PCA9517D,118 equivalent, this device delivers lock-up-free bidirectional buffering with active-HIGH enable control, powered-off high-impedance I/Os, and precise input thresholds (0.3×VCCA / 0.3×VCCB) critical for robust arbitration and clock stretching across voltage domains.
Technical Context
The PCA9517D,118 implements dual independent open-drain buffers with asymmetric input threshold design: A-side inputs trigger at 0.3×VCCA (enabling reliable detection down to 0.9 V supply), while B-side inputs use 0.3×VCCB with hysteresis to prevent false triggering during noise or slow edges. Its internal power-good circuit requires VCCA > 0.8 V and VCCB > 2.5 V before driver activation.
Propagation delays are asymmetric and supply-dependent - e.g., A-to-B tPHL ranges from 60 ns (typ) at VCCA ≥ 3 V to 230 ns (max), while B-to-A tPLH reaches 250 ns (max); EN pin timing requires ≥100 ns setup/hold relative to START/STOP to avoid bus hang. All I/Os remain 5 V tolerant even when unpowered.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| A-side supply (VCCA) | 0.9 V to 5.5 V - enables direct interface with ultra-low-voltage logic (e.g., 0.9 V IO banks of modern MCUs) |
| B-side supply (VCCB) | 2.7 V to 5.5 V - compatible with standard 3.3 V or 5 V I²C buses without level-shifting components |
| Max clock frequency | 400 kHz - supports Fast-mode I²C but system-level speed limited by cumulative repeater delay |
| Input threshold (A-side) | 0.3×VCCA - ensures LOW detection stability across full VCCA range, including sub-1 V operation |
| Output VOL (A-side) | 0.1 V (typ) at 6 mA - provides hard ground-referenced LOW for low-voltage slaves requiring tight VOL specs |
| Output VOL (B-side) | 0.52 V (typ) at 100 µA - sets controlled LOW offset to prevent lock-up when interfacing with static-offset buffers |
| ESD rating | 2000 V HBM - meets industrial-grade robustness requirements for board-level handling and field deployment |
Pinout & Package
PCA9517D,118 is supplied in SO8 (SOT96-1) package: plastic small outline, 8-lead, 3.9 mm body width, standard 1.27 mm lead pitch. Pin 1 is marked with dot or bevel; pin 1 index located at top-left corner when notch faces upward.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCCA | A-side supply input | Powers internal A-side comparators and sets 0.3×VCCA input threshold; not used for logic power (all I/Os powered by VCCB) |
| SCLA | A-side serial clock I/O | Open-drain bidirectional clock line - pulled LOW by internal driver when B-side falls below 0.3×VCCB |
| SDAA | A-side serial data I/O | Open-drain bidirectional data line - same control logic as SCLA; supports arbitration and clock stretching |
| GND | Ground reference | Common return for both sides; required for proper comparator reference and ESD path |
| EN | Active-HIGH enable input | Internal pull-up to VCCB; must transition only during bus idle to prevent hang or protocol corruption |
| SDAB | B-side serial data I/O | Open-drain bidirectional data line - driven LOW to ~0.5 V (not ground) to avoid false recognition by internal input |
| SCLB | B-side serial clock I/O | Open-drain bidirectional clock line - same VOL behavior as SDAB; enables transparent clock stretching |
| VCCB | B-side supply input | Powers all logic, drivers, and I/Os; defines VIH/VIL thresholds for B-side pins and EN pin |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional capacitance isolation | Enables two independent 400 pF I²C segments - eliminates bus loading issues when connecting high-capacitance peripherals |
| Lock-up free architecture | Prevents bus deadlock via asymmetric VOL/VIL offset (70 mV) on B-side - ensures LOW transitions are correctly recognized across voltage domains |
| Powered-off high-impedance I/Os | All pins (SDAA, SCLA, SDAB, SCLB, EN) float to high-Z when VCCA = 0 V or VCCB = 0 V - allows safe hot-plug or partial power-down |
| Static offset compatibility | A-side accepts connection to any buffer with static/dynamic offset (e.g., PCA9515A), while B-side avoids conflict with other static-offset devices |
| Star and series topology support | Multiple A-sides can share one bus (star), or devices can cascade A→B (series) - no offset voltage accumulation, only time-of-flight delay |
Applications
| Multi-Rail Sensor Hub | Low-Voltage MCU Peripheral Interface |
|---|---|
Use Scenario: A 3.3 V host MCU communicates with 0.9 V MEMS sensors and 1.2 V ADCs on separate I²C segments. IC Role / Device Role / Timing Role: PCA9517D,118 acts as voltage-translating repeater, isolating capacitance and enabling arbitration across rails. Use Value: Eliminates need for discrete MOSFET translators; preserves Fast-mode timing integrity while supporting sub-1 V logic thresholds. |
Use Scenario: An ultra-low-power microcontroller (VDDIO = 1.0 V) interfaces with legacy 3.3 V EEPROM and temperature sensors. IC Role / Device Role / Timing Role: PCA9517D,118 serves as A-side master translator, providing hard 0.1 V LOW output compatible with 1.0 V logic VOL spec. Use Value: Guarantees reliable ACK/NACK signaling where 0.3×VCCA threshold prevents false HIGH detection on weak pull-ups. |
| I²C Bus Extension for Industrial PLC | Hot-Swappable Module Backplane |
Use Scenario: A 5 V main controller extends I²C to remote 2.7 V I/O modules over 20 cm PCB traces with >200 pF total capacitance. IC Role / Device Role / Timing Role: PCA9517D,118 functions as segment repeater, splitting bus into two <400 pF domains with controlled propagation delay. Use Value: Maintains 400 kHz timing margin despite trace capacitance; EN pin allows software-controlled isolation during module insertion/removal. |
Use Scenario: Modular carrier board uses PCA9517D,118 to isolate hot-pluggable daughter cards (each with unique VCCA) from shared 3.3 V backplane bus. IC Role / Device Role / Timing Role: PCA9517D,118 operates in star topology - all A-sides connect to common low-voltage card bus, B-side links to backplane. Use Value: Prevents backplane voltage sag or noise injection during card insertion; powered-off high-Z I/Os ensure zero current draw from unpowered modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C bus repeater applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9515AD,118 | Footprint-compatible SO8; lacks A-side 0.9 V support (min VCCA = 2.7 V); no 0.3×VCCA threshold - uses fixed 0.65 V | Cannot interface with sub-2.7 V logic; unsuitable for ultra-low-voltage sensor nodes or advanced process MCUs | Select PCA9515AD,118 only when both sides operate ≥2.7 V and lower VOL tolerance is acceptable |
| TCA9517PWR | TSSOP8 package; identical VCCA/VCCB ranges and thresholds; 10% faster max tPHL (70 ns typ vs 80 ns); same EN timing constraints | Same functional behavior but different footprint - requires PCB redesign; higher thermal resistance in TSSOP8 may limit high-density layouts | Choose TCA9517PWR if TSSOP8 is preferred for space-constrained designs and thermal derating is verified |
Compared with PCA9517D,118, PCA9515AD,118 sacrifices ultra-low-voltage A-side capability for simpler biasing, while TCA9517PWR offers identical functionality in a smaller package at the cost of layout compatibility and thermal performance trade-offs.
Availability
PCA9517D,118 is available at Aetrix Electronics and suitable for multi-rail sensor hubs, low-voltage MCU peripheral interfaces, and industrial I²C bus extension requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCA9517D,118 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 management, and embedded processing technologies.
The PCA9517D,118 belongs to NXP's I²C-bus repeater and level translator product line, engineered specifically to solve voltage-domain interoperability and bus capacitance challenges in heterogeneous embedded systems.
FAQ
What is the minimum A-side supply voltage supported by the PCA9517D,118?
The PCA9517D,118 supports an A-side supply (VCCA) as low as 0.9 V, with input thresholds dynamically scaled to 0.3×VCCA - enabling reliable operation with modern ultra-low-voltage microcontrollers and sensors. This specification is validated across the full operating temperature range (−40 °C to +85 °C) and is not a typical-only value.
Can the PCA9517D,118 be used with only one supply voltage applied?
Yes - the PCA9517D,118 features powered-off high-impedance I/Os: when either VCCA or VCCB is at 0 V, all pins (SDAA, SCLA, SDAB, SCLB, EN) enter high-impedance state, preventing back-powering or contention. However, drivers remain disabled until both VCCA > 0.8 V and VCCB > 2.5 V are met.
Why does the PCA9517D,118 have different VOL specifications for A-side and B-side outputs?
The PCA9517D,118 uses asymmetric VOL design: A-side drives a hard 0.1 V (typ) LOW to meet ultra-low-voltage logic requirements, while B-side outputs ~0.52 V to create a deliberate 70 mV offset below its 0.43 V input threshold - preventing self-triggering and ensuring lock-up free operation during bidirectional transitions.
Is the EN pin of the PCA9517D,118 internally pulled up?
Yes - the EN pin of the PCA9517D,118 has an internal pull-up resistor to VCCB, making it active-HIGH by default. It requires no external pull-up for basic operation, though external control is recommended for deterministic bus isolation during power sequencing or fault recovery.
Does the PCA9517D,118 support clock stretching across voltage domains?
Yes - the PCA9517D,118 fully supports clock stretching in both directions: a slave holding SCL LOW on the A-side will propagate that condition to the B-side, and vice versa. Its internal comparators and driver enable timing-transparent arbitration and stretching, preserving I²C protocol integrity across voltage boundaries.
PCA9517D,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Buffer, ReDriver
- Applications:
- I2C
- Input:
- 2-Wire Bus
- Output:
- 2-Wire Bus
- Data Rate (Max):
- 400kHz
- Number of Channels:
- 2
- Delay Time:
- -
- Signal Conditioning:
- -
- Capacitance - Input:
- 6 pF
- Voltage - Supply:
- 2.7V ~ 5.5V
- Current - Supply:
- 5mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
PCA9517D,118 FAQ
1.How can I place an order for PCA9517D,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9517D,118 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 PCA9517D,118 reliable?
The price and inventory of PCA9517D,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9517D,118 is usually 5 days.
3.What payment methods are accepted for PCA9517D,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9517D,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9517D,118?
PCA9517D,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9517D,118 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 PCA9517D,118?
For technical support, including PCA9517D,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9517D,118 requirements.
6.How does Aetrix verify that PCA9517D,118 is sourced from the original manufacturer or authorized distributors?
All PCA9517D,118 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 PCA9517D,118 meets industry standards.
7.What is the process for return or replacement of PCA9517D,118?
All PCA9517D,118 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9517D,118, 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 PCA9517D,118 part is unused and in its original packaging.
Return procedure for PCA9517D,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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