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NXP Semiconductors PCA9508D,118
- Part No.:
- PCA9508D,118
- Manufacturer:
- NXP Semiconductors
- Category:
- Signal Buffers, Repeaters, Splitters
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
PCA9508D,118.pdf
- Description:
- IC REDRIVER I2C HOTSWAP 1CH 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:10,052
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Product details
Overview
The PCA9508D,118 from NXP Semiconductors is a hot-swappable, bidirectional I²C-bus repeater enabling level translation between 0.9 V–5.5 V (A side) and 2.7 V–5.5 V (B side), with zero static offset on the A side and controlled 0.5 V LOW output on the B side. It isolates bus capacitance up to 400 pF per side, supports arbitration and clock stretching, and features active-HIGH EN control with undervoltage lockout (UVLO) for safe power sequencing in mixed-voltage embedded systems.
For engineers reviewing the PCA9508D,118 datasheet, PCA9508D,118 pinout, PCA9508D,118 application, or PCA9508D,118 equivalent, key selection criteria include its dual-supply hot-swap capability, 0.5 V B-side VOL tolerance for reliable LOW detection, 400 kHz system timing compatibility, and SO8 package suitability for space-constrained industrial I²C expansion designs.
Technical Context
The PCA9508D,118 implements two independent open-drain bidirectional buffers-one per bus side-with separate voltage references: A-side input threshold at 0.5×VCC(A) and B-side input threshold fixed at 0.43 V. Its STOP/IDLE detect circuitry enables hot-swap insertion without bus contention, while UVLO ensures drivers remain disabled until VCC(B) > 2.5 V and VCC(A) > 0.8 V.
Signal translation operates asymmetrically: A-side LOWs drive B-side to ~0.5 V (not ground), whereas B-side LOWs pull A-side to near 0 V. This eliminates cumulative offset in series configurations and prevents lock-up by ensuring B-side internal pull-down (0.5 V) falls below its own input threshold (0.43 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| A-side VCC range | 0.9 V to 5.5 V - supports ultra-low-voltage I²C nodes down to sub-1 V logic, e.g., 0.9 V FPGA I/O banks |
| B-side VCC range | 2.7 V to 5.5 V - interfaces directly with 3.3 V or 5 V microcontrollers and peripherals |
| Max clock frequency | 400 kHz - compatible with Fast-mode I²C and SMBus, though propagation delays may limit full-system speed |
| B-side VOL (IOL = 100 µA) | 0.47–0.6 V - guarantees robust LOW recognition by downstream devices with VIL ≤ 0.3×VCC(B) |
| A-side VOL (IOL = 6 mA) | 0.1–0.2 V - delivers hard ground-referenced LOWs critical for low-VCC(A) slaves (e.g., 1.2 V sensors) |
| Propagation delay (A→B) | 25–110 ns - enables tight timing budgets in high-speed I²C segments with minimal added latency |
| ESD rating (HBM) | 6000 V - exceeds JEDEC JESD22-A114, suitable for board-level handling in manufacturing environments |
Pinout & Package
PCA9508D,118 is supplied in an 8-pin SO8 package (SOT96-1), 3.9 mm body width, with gull-wing leads and standard 1.27 mm pitch. Pin 1 is marked with a dot or notch; the package is RoHS-compliant and reflow-solderable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC(A) | A-side supply voltage input | Powers A-side comparators and sets 0.5×VCC(A) input threshold; must be ≥0.8 V for enable |
| SCLA | Open-drain serial clock A-side I/O | Connects to low-voltage I²C master/slave clock line; driven LOW to 0.1 V typical |
| SDAA | Open-drain serial data A-side I/O | Connects to low-voltage I²C master/slave data line; same drive characteristics as SCLA |
| GND | Supply ground reference | Common return for both sides; required for proper comparator biasing and UVLO operation |
| EN | Active-HIGH repeater enable | Internal 100 kΩ pull-up to VCC(B); must transition only during bus idle to avoid hang conditions |
| SDAB | Open-drain serial data B-side I/O | Connects to 2.7–5.5 V I²C bus; pulled LOW to ~0.5 V, not ground |
| SCLB | Open-drain serial clock B-side I/O | Same electrical behavior as SDAB; supports arbitration and clock stretching across repeater |
| VCC(B) | B-side supply voltage input | Powers all logic and B-side drivers; must be ≥2.5 V for enable; tolerant to 0 V during hot-swap |
Key Features
| Feature | Design Value |
|---|---|
| Zero-offset A-side translation | Drives A-side LOW to <0.2 V, enabling direct connection to sub-1 V logic without level-shifter degradation |
| Hot-swap IDLE/STOP detection | Prevents bus contention during live card insertion by delaying connection until global bus idle or STOP condition |
| Dual-supply sequencing independence | VCC(A) and VCC(B) may power up in any order; device remains high-Z until both meet UVLO thresholds |
| Powered-off 5 V-tolerant I/O | All SDA/SCL/EN pins withstand 5.5 V even when unpowered - eliminates need for external protection diodes |
| Lock-up free B-side architecture | Internal 0.5 V pull-down and 0.43 V input threshold ensure B-side LOWs are always recognized, avoiding deadlocks |
Applications
| Industrial Sensor Hub | Multi-Voltage Server Management |
|---|---|
Use Scenario: A 1.2 V temperature sensor array communicates over I²C to a 3.3 V baseband processor in a programmable logic controller. IC Role / Device Role / Timing Role: PCA9508D,118 acts as a level-translating repeater, isolating 400 pF sensor bus capacitance from the main controller bus while translating 1.2 V signals to 3.3 V-compatible levels. Use Value: Enables direct integration of ultra-low-power sensors without external level shifters or bus redesign, preserving Fast-mode timing at 400 kHz. | Use Scenario: A server motherboard uses separate 1.8 V PMBus voltage monitors and 3.3 V IPMI controllers on shared I²C management bus. IC Role / Device Role / Timing Role: PCA9508D,118 serves as a hot-swappable repeater between 1.8 V monitoring ICs and 3.3 V BMC, supporting dynamic module insertion/removal. Use Value: Eliminates bus corruption during field-replaceable unit (FRU) swaps and maintains signal integrity across voltage domains without layout changes. |
| Automotive Body Control Module | Medical Wearable Data Aggregation |
Use Scenario: A 5 V microcontroller coordinates multiple 1.2 V battery fuel gauges and 2.8 V ambient light sensors via I²C in a vehicle door module. IC Role / Device Role / Timing Role: PCA9508D,118 provides bidirectional level translation and capacitance isolation between high- and low-voltage sensor clusters. Use Value: Reduces EMI susceptibility by splitting long I²C traces into shorter, isolated segments while maintaining arbitration transparency. | Use Scenario: A wearable health patch integrates 0.9 V ECG analog front-end and 3.3 V Bluetooth SoC on a single PCB with constrained trace length. IC Role / Device Role / Timing Role: PCA9508D,118 functions as a compact, low-power repeater enabling I²C communication between sub-1 V analog sensors and digital radio. Use Value: Achieves <1 µA quiescent current in powered-off state and supports 0.9 V operation - critical for multi-day battery life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C-bus repeater applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9517AD,118 | Higher ESD (6.5 kV HBM), identical SO8 footprint and pinout, but lacks A-side 0.9 V support - minimum VCC(A) = 0.9 V not guaranteed | Best suited for 1.8 V+ systems where enhanced ESD robustness is prioritized over ultra-low-voltage translation | Select PCA9517AD,118 only if system VCC(A) ≥ 1.8 V and ESD immunity >6 kV is required; not drop-in for 0.9–1.2 V use cases |
| PCA9509D,118 | Static offset on A-side (not B-side), VCC(A) = 1.1 V to VCC(B)−1 V, no hot-swap IDLE/STOP detection circuitry | Designed for fixed-voltage translation where hot-swap is unnecessary and A-side voltage is tightly coupled to B-side rail | Choose PCA9509D,118 for cost-sensitive, non-hot-swap applications with matched supply rails; avoid where zero-offset A-side or live insertion is needed |
Compared with PCA9517AD,118 and PCA9509D,118, the PCA9508D,118 uniquely supports true 0.9 V A-side operation with hot-swap safety and zero-offset translation - making it the only option for battery-powered sub-1 V sensor interfaces requiring live module replacement.
Availability
PCA9508D,118 is available at Aetrix Electronics and suitable for industrial sensor hubs, automotive body control modules, and medical wearable data aggregation requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for PCA9508D,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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface and power management ICs.
The PCA9508D,118 belongs to NXP's I²C-bus repeater product line, engineered specifically for robust, hot-swappable level translation in mixed-voltage embedded systems where bus isolation, low-voltage compatibility, and timing transparency are critical.
FAQ
What is the minimum operating voltage on the A-side supply (VCC(A)) for PCA9508D,118?
The PCA9508D,118 supports A-side operation down to 0.9 V, as confirmed in Table 5 of the datasheet. This enables direct interfacing with ultra-low-power microcontrollers and sensors operating at sub-1 V logic levels, while maintaining full I²C functionality including arbitration and clock stretching. Below 0.9 V, the internal 0.5×VCC(A) input threshold becomes invalid and driver enablement fails.
Can PCA9508D,118 be used in a star topology with multiple A-side buses?
Yes, the PCA9508D,118 allows multiple A-side buses to connect in a star configuration, as explicitly stated in the General Description. Its A-side drivers are designed for direct interconnection without offset accumulation, enabling one master to communicate with multiple slave branches while maintaining signal integrity and hot-swap capability on each segment.
Does PCA9508D,118 support clock stretching across the repeater?
Yes, the PCA9508D,118 fully supports clock stretching in both directions, as documented in the Features section and Functional Description. When a slave holds SCL LOW on either side, the repeater transparently extends the LOW period to the opposite bus, preserving timing-critical interactions required by slow peripherals like EEPROMs or ADCs.
What happens to PCA9508D,118 I/O pins when VCC(B) = 0 V but VCC(A) is applied?
When VCC(B) = 0 V, all PCA9508D,118 I/O pins (SDAA, SCLA, SDAB, SCLB, EN) enter high-impedance state regardless of VCC(A) presence, as specified in the General Description and Functional Description. This 5 V-tolerant powered-off behavior protects downstream devices and eliminates need for external isolation components during partial power-down scenarios.
Is PCA9508D,118 pin-compatible with PCA9515A or PCA9517A?
Yes, the PCA9508D,118 is a footprint and functional replacement for PCA9515, PCA9515A, PCA9517, and PCA9517A, as stated in the Features section. All share identical SO8 (SOT96-1) and TSSOP8 (SOT505-1) packages and pin assignments, enabling drop-in substitution - though PCA9508D,118 adds 0.9 V A-side support and hot-swap logic not present in earlier variants.
PCA9508D,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 - Hotswap
- Input:
- 2-Wire Bus
- Output:
- 2-Wire Bus
- Data Rate (Max):
- 400kHz
- Number of Channels:
- 1
- Delay Time:
- -
- Signal Conditioning:
- -
- Capacitance - Input:
- 5.2 pF
- Voltage - Supply:
- 2.7V ~ 5.5V
- Current - Supply:
- 1mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
PCA9508D,118 FAQ
1.How can I place an order for PCA9508D,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9508D,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 PCA9508D,118 reliable?
The price and inventory of PCA9508D,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9508D,118 is usually 5 days.
3.What payment methods are accepted for PCA9508D,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9508D,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9508D,118?
PCA9508D,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9508D,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 PCA9508D,118?
For technical support, including PCA9508D,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9508D,118 requirements.
6.How does Aetrix verify that PCA9508D,118 is sourced from the original manufacturer or authorized distributors?
All PCA9508D,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 PCA9508D,118 meets industry standards.
7.What is the process for return or replacement of PCA9508D,118?
All PCA9508D,118 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9508D,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 PCA9508D,118 part is unused and in its original packaging.
Return procedure for PCA9508D,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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