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NXP Semiconductors PCA9509GM,125
- Part No.:
- PCA9509GM,125
- Manufacturer:
- NXP Semiconductors
- Category:
- Signal Buffers, Repeaters, Splitters
- Package:
- 8-XFQFN Exposed Pad
- Datasheet:
-
PCA9509GM,125.pdf
- Description:
- IC REDRIVER I2C 2CH 400KHZ 8XQFN
- Quantity:
- Payment:
- Shipping:
Inventory:34,087
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Product details
Overview
The PCA9509GM,125 from NXP Semiconductors is a bidirectional I²C-bus/SMBus level-translating repeater enabling 1.35 V–2.5 V low-voltage processors to interface with 3.0 V–5.5 V I²C/SMBus peripherals. It provides isolated buffering for SDA and SCL lines, supports arbitration and clock stretching, operates up to 400 kHz, and features lock-up-free current-sensing logic on port A. It is used in mixed-voltage embedded systems such as battery-powered sensor hubs interfacing ultra-low-power microcontrollers with legacy 3.3 V or 5 V I²C peripherals.
For engineers reviewing the PCA9509GM,125 datasheet, PCA9509GM,125 pinout, PCA9509GM,125 application, or PCA9509GM,125 equivalent, this device serves as a critical voltage-translation repeater where bus capacitance isolation, robust low-voltage operation down to 1.35 V, and SMBus-compliant port B interoperability are required - especially in space-constrained portable electronics requiring XQFN8 packaging.
Technical Context
The PCA9509GM,125 implements dual open-drain bidirectional buffers with asymmetric drive architecture: port A uses a 1 mA current-source pull-up and 200 Ω pull-down to achieve ~0.2 V LOW output and ~0.15 V input threshold (VILc), preventing bus lock-up during contention; port B employs hard-switched pull-downs compliant with SMBus I/O levels (VIL = 0.3×VCC(B)) and tolerates up to 5.5 V even when unpowered.
Its enable (EN) pin is active HIGH and must be asserted only during bus idle states; internal power-on reset ensures drivers remain disabled until VCC(A) > 0.8 V and VCC(B) > 2.5 V. Propagation delays range from −139 ns (A→B HIGH transition) to 226 ns (A→B second-stage HIGH transition), supporting Standard- and Fast-mode I²C timing with minimal added latency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Port A Voltage Range | 1.35 V to VCC(B) − 1.0 V - enables direct interface with 1.35 V, 1.8 V, or 2.5 V logic without external pull-ups |
| Port B Voltage Range | 3.0 V to 5.5 V - supports standard 3.3 V and 5 V I²C/SMBus systems with overvoltage tolerance |
| Max Clock Frequency | 400 kHz - compatible with I²C Fast-mode; system-level frequency may be lower due to repeater delay |
| Bus Capacitance Support | Up to 400 pF on port B - extends I²C bus length or node count while isolating capacitance between sides |
| Input Threshold (Port A) | VILc = +0.15 V (typical) - ensures reliable LOW detection without false triggering under low-swing conditions |
| Output LOW Voltage (Port A) | VOL = 0.2 V (typical) - maintains sufficient noise margin for sub-1.35 V logic while avoiding lock-up |
| ESD Protection | 2000 V HBM, 1000 V CDM - meets industrial-grade robustness requirements per JESD22 standards |
Pinout & Package
XQFN8 package: plastic, extremely thin quad flat no-lead package; 8 terminals; body size 1.6 mm × 1.6 mm × 0.5 mm; thermal pad exposed on bottom; RoHS-compliant; moisture sensitivity level (MSL) 1 (unlimited floor life at ≤30 °C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC(A) | Port A power supply | Supplies 1.35 V–(VCC(B)−1.0 V); powers internal current-source pull-up and sensing circuitry |
| A1 / A2 | Port A bidirectional I/O (SDA/SCL) | Open-drain, high-impedance when unpowered; no external pull-up required due to integrated 1 mA current source |
| GND | Ground reference | Common return for both ports; ground offset >50 mV risks misinterpretation of LOW levels on port A |
| EN | Enable input (active HIGH) | Asserted only during bus idle; disables drivers to isolate faulty slaves during power-up sequencing |
| B2 / B1 | Port B bidirectional I/O (SDA/SCL) | SMBus/I²C-compliant; 5 V tolerant; requires external pull-up resistors; interoperable with all standard I²C masters/slaves |
| VCC(B) | Port B power supply | Supplies 3.0 V–5.5 V; defines port B logic thresholds and drives capability; powers port B output stages |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional capacitance isolation | Enables 400 pF max load on port B while decoupling port A bus loading - extends physical bus reach and node count |
| Lock-up free current-sensing logic | Port A uses differential threshold (VILc ≈ 0.15 V, VOL ≈ 0.2 V) to prevent deadlocks during multi-master arbitration or clock stretching |
| No external pull-ups on port A | Integrated 1 mA current-source pull-up eliminates board space and BOM cost for low-voltage side termination |
| Powered-off high-impedance pins | All I/Os enter high-Z state when either VCC(A) or VCC(B) is absent - prevents back-driving or leakage in partial-power-down systems |
| Support for arbitration & clock stretching | Preserves I²C protocol integrity across translation boundary - essential for multi-master systems and slave-controlled timing |
Applications
| Mobile Sensor Hub | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Ultra-low-power MCU (1.35 V I²C) reads data from multiple 3.3 V environmental sensors and EEPROMs in a compact wearable device. IC Role / Device Role / Timing Role: Level-translating repeater bridging voltage domains while preserving I²C timing, arbitration, and clock stretch behavior. Use Value: Eliminates need for discrete level shifters and external pull-ups on the 1.35 V side, reducing PCB area by >30% and power consumption from static pull-up current. |
Use Scenario: Programmable logic controller interfaces legacy 5 V I²C temperature and pressure transducers with a modern 1.8 V ARM-based controller. IC Role / Device Role / Timing Role: Bidirectional buffer isolating bus capacitance and translating signals between non-overlapping voltage domains. Use Value: Enables drop-in integration of new low-voltage controllers into existing 5 V sensor infrastructure without redesigning bus topology or timing margins. |
| Automotive Body Control Unit | Medical Point-of-Care Monitor |
|
Use Scenario: 2.5 V microcontroller communicates with 3.3 V CAN-to-I²C bridge and battery fuel gauge ICs in a vehicle body control module. IC Role / Device Role / Timing Role: Voltage translator ensuring reliable START/STOP condition recognition and ACK/NACK propagation across voltage boundaries. Use Value: Guarantees deterministic bus recovery after power cycling and prevents lock-up during cold-cranking voltage sag on port A supply. |
Use Scenario: Portable diagnostic monitor uses a 1.8 V SoC to manage 5 V I²C-connected ECG front-end and flash memory in a battery-operated clinical device. IC Role / Device Role / Timing Role: Isolating repeater maintaining signal integrity and protocol compliance while enabling safe hot-plug of peripheral modules. Use Value: Supports MSL-1 reflow compatibility and zero standby current draw when unpowered - critical for FDA-regulated battery runtime certification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C level-translating repeater applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA9517DGKR | Single-supply operation (VCC = 1.65–5.5 V); no separate port A/B supplies; fixed 1.8 V–5.5 V translation; lacks port A current-source pull-up | Requires external pull-ups on both sides; less suitable for sub-1.8 V systems like 1.35 V CPUs | Choose TCA9517DGKR when unified supply simplifies power design and 1.35 V operation is not required. |
| PCA9515ADP | Legacy 2-channel repeater; supports only 2.7–5.5 V on both ports; no low-voltage port A; no current-source pull-up; higher propagation delay (>300 ns) | Cannot interface with 1.35 V or 1.8 V processors; limited to 3.3 V/5 V-only systems | Choose PCA9515ADP only for backward-compatible upgrades in existing 3.3 V/5 V designs where 1.35 V support is unnecessary. |
Compared with TCA9517DGKR and PCA9515ADP, the PCA9509GM,125 uniquely supports true 1.35 V operation with integrated port A pull-up, making it the only option for next-generation ultra-low-power microcontrollers - while its XQFN8 footprint delivers 64% smaller area than SO8 alternatives.
Availability
The PCA9509GM,125 is available at Aetrix Electronics and suitable for mobile sensor hubs, industrial PLC I/O modules, automotive body control units, and medical point-of-care monitors requiring stable component supply across extended product lifecycles.
Supply support for PCA9509GM,125 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 core expertise in interface, power management, and embedded processing technologies.
The PCA9509GM,125 belongs to NXP's I²C/SMBus interface repeater family, designed specifically to solve voltage-domain bridging challenges in space-constrained, mixed-voltage embedded systems - emphasizing reliability, protocol fidelity, and ultra-low-voltage compatibility.
FAQ
What is the minimum operating voltage on port A for PCA9509GM,125?
The PCA9509GM,125 supports port A supply voltages from 1.35 V to VCC(B) − 1.0 V. Operation below 1.35 V is not guaranteed; for applications requiring <1.35 V, NXP specifies the PCA9509A as a drop-in replacement. The 1.35 V minimum ensures proper function of the internal current-source pull-up and lock-up prevention circuitry in the PCA9509GM,125.
Does PCA9509GM,125 require external pull-up resistors on port A?
No, the PCA9509GM,125 does not require external pull-up resistors on port A because it integrates a 1 mA current-source pull-up on each A1 and A2 terminal. This eliminates BOM cost and PCB layout complexity for the low-voltage side, distinguishing it from generic level shifters that mandate external termination.
How does PCA9509GM,125 prevent I²C bus lock-up during contention?
The PCA9509GM,125 prevents lock-up using asymmetric port A thresholds: its output LOW is ~0.2 V, while its input contention threshold (VILc) is ~0.15 V - a 50 mV offset ensures an internally driven LOW is not re-detected as input, breaking potential feedback loops. This design is explicitly validated in the PCA9509GM,125 datasheet for multi-master arbitration scenarios.
What is the maximum allowable ground offset between port A and port B in PCA9509GM,125?
The PCA9509GM,125 requires ground offset between port A and port B to be ≤50 mV. Exceeding this risks misinterpreting port A LOW signals due to shared current paths between external drivers and the internal 200 Ω pull-down. This specification is derived from worst-case VILc (90 mV at cold temperature) and is strictly enforced in the PCA9509GM,125 functional description.
Is PCA9509GM,125 compatible with Fast-mode Plus (1 MHz) I²C devices?
No, the PCA9509GM,125 is rated for 0 Hz to 400 kHz operation and is not specified for Fast-mode Plus (1 MHz). Its propagation delays (up to 226 ns) and transition times exceed timing budgets for 1 MHz I²C, and the datasheet explicitly limits maximum clock frequency to 400 kHz for the PCA9509GM,125 across all operating conditions.
PCA9509GM,125 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 8-XFQFN Exposed Pad
- 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:
- 2 pF
- Voltage - Supply:
- 3V ~ 5.5V
- Current - Supply:
- 3mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-XQFNU (1.6x1.6)
PCA9509GM,125 FAQ
1.How can I place an order for PCA9509GM,125 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9509GM,125 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 PCA9509GM,125 reliable?
The price and inventory of PCA9509GM,125 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9509GM,125 is usually 5 days.
3.What payment methods are accepted for PCA9509GM,125?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9509GM,125 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9509GM,125?
PCA9509GM,125 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9509GM,125 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 PCA9509GM,125?
For technical support, including PCA9509GM,125 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9509GM,125 requirements.
6.How does Aetrix verify that PCA9509GM,125 is sourced from the original manufacturer or authorized distributors?
All PCA9509GM,125 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 PCA9509GM,125 meets industry standards.
7.What is the process for return or replacement of PCA9509GM,125?
All PCA9509GM,125 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9509GM,125, 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 PCA9509GM,125 part is unused and in its original packaging.
Return procedure for PCA9509GM,125:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCA9509GM,125 Tags
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