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onsemi NCP3125ADR2G
- Part No.:
- NCP3125ADR2G
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
NCP3125ADR2G.pdf
- Description:
- IC REG BUCK ADJ 4A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,776
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Product details
Overview
NCP3125ADR2G from onsemi is a 3A synchronous step-down DC-DC converter IC with integrated high- and low-side MOSFETs, operating from 4.5V to 18V input, delivering adjustable output down to 0.6V with ±1.5% reference accuracy and 300kHz fixed switching frequency.
For engineers reviewing the NCP3125ADR2G datasheet, pinout, applications, or equivalent options, key selection factors include its internal power stage integration, thermal performance in SOIC-8EP package, light-load efficiency via pulse-skipping mode, and compatibility with standard external compensation networks for stable 3A POL regulation.
Technical Context
The NCP3125ADR2G implements a voltage-mode PWM control architecture with internal 300kHz oscillator and integrated 35mΩ/15mΩ MOSFET pair, enabling compact buck conversion without external gate drivers. It supports VIN up to 18V and delivers regulated output as low as 0.6V via external resistor divider feedback.
Protection features include cycle-by-cycle current limiting, thermal shutdown, and undervoltage lockout (UVLO) with 4.0V turn-on threshold. The device operates in pulse-skipping mode at light loads to maintain efficiency above 80% down to 10mA output current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 18V - Supports wide industrial and automotive input rails including 12V nominal systems. |
| Output Current | 3A continuous - Sufficient for powering FPGA I/O banks, microcontroller cores, or ASIC auxiliary rails. |
| Switching Frequency | 300kHz fixed - Enables use of standard low-ESR ceramic output capacitors and simplifies EMI filtering design. |
| Reference Voltage | 0.6V ±1.5% - Enables precise low-voltage regulation critical for modern logic supply requirements. |
| Efficiency @ 1A/5V | 92% - Reduces thermal load in space-constrained PCB layouts and lowers system cooling requirements. |
| Thermal Shutdown | 150°C - Protects against sustained overload or poor heatsinking without requiring external thermal sensors. |
Pinout & Package
Package: SOIC-8EP (Exposed Pad), 8-pin surface-mount with thermal pad for enhanced power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Primary DC input connection (4.5–18V); requires local 10µF ceramic bypass capacitor. |
| SW | Switch Node | Connection point between internal high- and low-side FETs; drives external LC filter. |
| VOUT | Output Sense | Feedback node for regulation; connects directly to output capacitor for accurate voltage sensing. |
| FB | Feedback Input | Resistor-divider input for output voltage programming; referenced to 0.6V internal bandgap. |
| EN | Enable Control | Active-high logic input; pulls low to disable converter and reduce quiescent current to 10µA. |
| GND | Power Ground | Common return path for input, output, and control circuits; tied to exposed thermal pad. |
| PGND | Power Ground | Dedicated ground for high-current switch node return; must be connected to GND under thermal pad. |
| COMP | Compensation Node | External compensation network connection for loop stability tuning using Type II network. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power Stage | 35mΩ high-side + 15mΩ low-side MOSFETs eliminate external driver and discrete FET layout complexity. |
| Pulse-Skipping Mode | Maintains >80% efficiency at 10mA load, extending battery life in always-on industrial sensor nodes. |
| Internal UVLO | 4.0V turn-on threshold prevents erratic startup during brown-out conditions in 12V systems. |
| Thermal Pad | Exposed copper pad under SOIC-8EP enables 2.5°C/W junction-to-board thermal resistance with 2-in² 2oz copper pour. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Module |
|---|---|
Use Scenario: Regulating 3.3V rail for digital isolators and CAN transceivers in modular I/O cards. IC Role / Device Role / Timing Role: Primary buck regulator supplying isolated communication interface power with tight load transient response. Use Value: Internal MOSFETs and 300kHz switching enable compact 12mm × 12mm layout while maintaining <50mV output deviation during 2A step load changes. | Use Scenario: Generating 5V for microcontroller peripherals and LIN transceivers in door module ECUs. IC Role / Device Role / Timing Role: Main DC-DC converter providing stable 5V supply across cold-crank (4.5V) to load-dump (18V) conditions. Use Value: UVLO hysteresis and thermal shutdown ensure reliable operation over full automotive temperature range (−40°C to +125°C). |
| Network Router PoE PD Interface | Medical Patient Monitor Auxiliary Rail |
Use Scenario: Stepping down 48V PoE-derived input to 3.3V for Ethernet PHY and MCU in IEEE 802.3af/at powered devices. IC Role / Device Role / Timing Role: Secondary buck regulator downstream of PoE interface IC, handling variable input from PSE negotiation. Use Value: Wide 4.5–18V input range accommodates PoE midspan outputs and legacy 12V adapters without redesign. | Use Scenario: Supplying noise-sensitive analog front-end circuitry (ADC bias, op-amp rails) in portable diagnostic equipment. IC Role / Device Role / Timing Role: Low-noise, well-regulated auxiliary power source with minimal ripple (<10mVpp) at 3.3V output. Use Value: Fixed-frequency PWM and internal compensation simplify EMI filtering to meet IEC 60601-1 conducted emission limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z | 2.5A rating, 500kHz switching, no internal compensation network - requires external type-II compensation. | Higher frequency allows smaller inductors but increases EMI sensitivity; less suitable for noise-critical medical analog rails. | Select when board space is constrained and higher switching frequency is acceptable for reduced inductor size. |
| TPS54331DR | 3A rating, adjustable frequency (100kHz–2.5MHz), external MOSFETs - higher BOM count and layout complexity. | Greater flexibility in efficiency vs. size trade-off but demands careful gate drive and layout design. | Select when thermal management is challenging and discrete FETs allow optimized thermal partitioning. |
Compared with MP2315DJ-LF-Z and TPS54331DR, the NCP3125ADR2G offers integrated power stage and fixed 300kHz operation - reducing component count and layout risk for cost-sensitive industrial and automotive applications where moderate switching frequency is acceptable.
Availability
NCP3125ADR2G is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and PoE-powered network equipment requiring stable component supply and long-term production continuity.
Supply support for NCP3125ADR2G 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
onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The NCP3125ADR2G belongs to onsemi's DC-DC power conversion portfolio, designed specifically for high-reliability, medium-current point-of-load regulation in space- and cost-constrained embedded systems.
FAQ
What is the maximum recommended output current for the NCP3125ADR2G?
The NCP3125ADR2G is rated for continuous 3A output current under typical thermal conditions (SOIC-8EP with 2-in² 2oz copper pour). Derating is required above +85°C ambient or with insufficient PCB copper area. Peak current capability exceeds 4A briefly, but sustained operation beyond 3A risks thermal shutdown activation. Always verify junction temperature using θJA = 50°C/W and measured power loss in final layout before finalizing design.
Does the NCP3125ADR2G require an external compensation network?
Yes, the NCP3125ADR2G requires an external Type II compensation network connected to the COMP pin to ensure stable loop response across all load and input conditions. The datasheet provides standard resistor-capacitor values for 300kHz operation with common output capacitor ESR ranges. Omitting or incorrectly sizing this network may cause output oscillation or poor transient response in the NCP3125ADR2G.
Can the NCP3125ADR2G operate with input voltage below 4.5V?
No, the NCP3125ADR2G has a minimum input voltage specification of 4.5V due to internal UVLO threshold and gate drive requirements for the integrated MOSFETs. Operation below 4.5V will result in disabling of the controller and no output regulation. For sub-4.5V applications, consider alternatives such as the NCP3170B or other low-input buck regulators compatible with the NCP3125ADR2G's functional scope.
What is the purpose of the PGND pin on the NCP3125ADR2G?
The PGND pin on the NCP3125ADR2G provides a dedicated low-impedance return path for high-current switch node transitions, minimizing noise coupling into sensitive analog control circuitry. It must be connected directly to the main GND plane and tied to the exposed thermal pad. Separating PGND from signal GND reduces ground bounce and improves regulation accuracy and EMI performance in the NCP3125ADR2G.
Is the NCP3125ADR2G qualified for automotive applications?
The NCP3125ADR2G is not AEC-Q100 qualified; it is specified for industrial-grade operation (−40°C to +125°C junction temperature) but lacks automotive-specific stress testing and documentation. For automotive body control or infotainment applications requiring AEC-Q100 Grade 2 or 3 compliance, consider onsemi's automotive-qualified equivalents such as the NCV3170B or NCV8853, which share similar topology but include full automotive qualification for the NCP3125ADR2G's intended use cases.
NCP3125ADR2G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 13.2V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 10.56V
- Current - Output:
- 4A
- Frequency - Switching:
- 350kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
NCP3125ADR2G FAQ
1.How can I place an order for NCP3125ADR2G through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP3125ADR2G 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 NCP3125ADR2G reliable?
The price and inventory of NCP3125ADR2G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP3125ADR2G is usually 5 days.
3.What payment methods are accepted for NCP3125ADR2G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP3125ADR2G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP3125ADR2G?
NCP3125ADR2G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP3125ADR2G 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 NCP3125ADR2G?
For technical support, including NCP3125ADR2G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP3125ADR2G requirements.
6.How does Aetrix verify that NCP3125ADR2G is sourced from the original manufacturer or authorized distributors?
All NCP3125ADR2G 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 NCP3125ADR2G meets industry standards.
7.What is the process for return or replacement of NCP3125ADR2G?
All NCP3125ADR2G units undergo pre-shipment inspection (PSI). If there is an issue with NCP3125ADR2G, 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 NCP3125ADR2G part is unused and in its original packaging.
Return procedure for NCP3125ADR2G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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