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onsemi NCP3126ADR2G
- Part No.:
- NCP3126ADR2G
- Manufacturer:
- onsemi
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
NCP3126ADR2G.pdf
- Description:
- IC REG BUCK ADJ 3A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,754
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Product details
Overview
NCP3126ADR2G from onsemi is a 3A synchronous buck 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% reference accuracy and 300kHz fixed switching frequency. It supports over-current, over-temperature, and under-voltage lockout protection in a thermally enhanced SOIC-8 package.
For engineers reviewing the NCP3126ADR2G datasheet, pinout, applications, or equivalent options, key selection criteria include input voltage range compatibility, integrated FET RDS(on) values (35mΩ/15mΩ), thermal performance in SOIC-8, current-mode control stability, and enable/PGOOD signal timing behavior.
Technical Context
The NCP3126ADR2G implements a current-mode PWM controller with internal slope compensation for stable operation across wide duty cycles. Its integrated 35mΩ high-side and 15mΩ low-side MOSFETs reduce external component count while enabling efficient 3A continuous output at up to 95% peak efficiency.
It features a precision 0.6V ±1% internal reference, programmable soft-start via external capacitor, and a power-good (PG) flag that asserts after output regulation is achieved within ±10% tolerance. The device operates with no external compensation required due to optimized internal loop response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 18V - supports 5V, 12V, and 15V intermediate bus rails without external regulators. |
| Output Current | 3A continuous - sufficient for powering FPGA I/O banks, microcontroller cores, or ASIC auxiliary rails. |
| Reference Voltage | 0.6V ±1% - enables accurate low-voltage outputs (e.g., 0.9V, 1.2V, 1.8V) with minimal resistor-divider error. |
| Switching Frequency | 300kHz fixed - balances EMI control and inductor size; avoids AM radio band and simplifies filter design. |
| High-Side RDS(on) | 35mΩ max at 25°C - limits conduction loss to ≤315mW at 3A, reducing thermal load in SOIC-8. |
| Low-Side RDS(on) | 15mΩ max at 25°C - improves light-load efficiency and reduces body-diode conduction losses. |
| Thermal Shutdown | 150°C typical - protects against sustained overload or poor PCB copper layout without latch-up. |
Pinout & Package
The NCP3126ADR2G is housed in an exposed-pad SOIC-8 (SOIC-8EP) package with thermal pad on underside for enhanced heat dissipation. Pin 1 is marked by a beveled corner or dot; the exposed pad must be soldered to a thermal plane for rated 3A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Power Supply | Connects to 4.5–18V source; requires local 10µF ceramic bypass near pin. |
| SW | Switch Node | Drives external inductor; high dv/dt node requiring tight layout and ground shielding. |
| GND | Power Ground | Common return for VIN, PGND, and thermal pad; must connect directly to exposed pad. |
| FB | Feedback Input | Senses output voltage via resistor divider; high-impedance node sensitive to noise coupling. |
| EN | Enable Control | Active-high logic input; 1.2V threshold allows direct MCU GPIO or open-drain control. |
| PG | Power-Good Output | Open-drain flag indicating regulated output within ±10%; requires pull-up resistor. |
| SS | Soft-Start Timing | Connects to capacitor to set ramp time; determines inrush current limiting duration. |
| PGND | Power Ground Return | Dedicated ground path for low-side FET; must tie to GND and thermal pad at single point. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated High/Low-Side MOSFETs | Eliminates need for external gate drivers and discrete FETs, reducing BOM count and layout area by ≥4 components. |
| Current-Mode PWM Control | Provides inherent cycle-by-cycle current limiting and fast transient response (<10µs to 50% load step). |
| Internal 0.6V Reference | Enables precise output setting without external reference IC, improving accuracy and reducing drift vs. temperature. |
| Thermally Enhanced SOIC-8EP | Exposed pad lowers θJA to 45°C/W (with 2-in² 2oz Cu), supporting full 3A load without heatsink. |
| Programmable Soft-Start | Prevents input inrush and output overshoot via external capacitor; eliminates need for sequencing controllers. |
Applications
| Industrial PLC I/O Module | Automotive Infotainment Core Rail |
|---|---|
Use Scenario: Powering 3.3V or 2.5V logic rails in modular PLC backplanes with variable input voltage (12V/24V). IC Role / Device Role / Timing Role: Primary buck regulator converting unregulated 12V bus to stable 3.3V for FPGA configuration and communication interfaces. Use Value: Integrated FETs and 300kHz switching allow compact, low-noise design meeting EN 55032 Class A emissions without added filtering. | Use Scenario: Generating 1.2V core supply for ARM-based infotainment SoCs in automotive head units. IC Role / Device Role / Timing Role: Main SoC core regulator with PGOOD signaling to processor reset controller for safe boot sequence. Use Value: ±1% reference and current-mode control ensure <±30mV output deviation during CPU burst loads, preventing brownout resets. |
| Networking Switch ASIC Auxiliary Rail | Medical Imaging Sensor Interface Board |
Use Scenario: Delivering 1.8V/2A to Ethernet switch ASIC SerDes blocks in enterprise switches. IC Role / Device Role / Timing Role: Secondary buck stage downstream of primary 5V rail, tightly regulated for high-speed interface integrity. Use Value: Low 15mΩ low-side RDS(on) minimizes dropout at light loads, maintaining regulation during link idle states. | Use Scenario: Providing clean 0.9V bias to CMOS image sensor analog front-end on portable ultrasound probe boards. IC Role / Device Role / Timing Role: Low-noise, low-ripple point-of-load regulator adjacent to sensitive analog circuitry. Use Value: Fixed 300kHz frequency enables predictable EMI filtering and avoids interference with 1–10MHz sensor sampling clocks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z (Monolithic Power) | 4.5–24V input, 3A, 500kHz switching, no PGOOD output | Lacks power-good signaling; requires external monitoring for safety-critical sequencing | Preferred where higher frequency allows smaller magnetics but PGOOD is not required |
| TPS54332DDAR (Texas Instruments) | 3.5–28V input, 3A, adjustable frequency (100kHz–2.5MHz), external FETs required | Higher design complexity due to external MOSFETs and compensation network | Chosen when wider input range or frequency tuning is needed, accepting increased BOM and layout effort |
Compared with MP2315DJ-LF-Z and TPS54332DDAR, the NCP3126ADR2G offers integrated FETs with PGOOD in SOIC-8, delivering lowest system-level component count and fastest time-to-operational output for mid-power industrial and automotive rails.
Availability
NCP3126ADR2G is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, and networking equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for NCP3126ADR2G 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 leader focused on energy-efficient innovation, delivering silicon solutions for automotive, industrial, cloud, medical, and IoT applications with emphasis on sustainability and reliability.
The NCP3126ADR2G belongs to onsemi's DC-DC power conversion portfolio, designed specifically for space-constrained, cost-sensitive mid-power applications needing high integration, robust protection, and simplified layout.
FAQ
What is the maximum recommended output current for NCP3126ADR2G under continuous operation?
The NCP3126ADR2G is rated for 3A continuous output current when mounted on a standard 4-layer PCB with 2-in² 2oz copper thermal pad connected to the exposed die pad. Derating is required above 70°C ambient or with reduced copper area; full 3A load assumes proper thermal design per onsemi AN-1117 layout guidelines.
Does NCP3126ADR2G require external compensation components?
No, the NCP3126ADR2G uses an internally compensated current-mode control architecture and operates stably with standard output capacitor ESR ranges. No external compensation network is needed-only the feedback resistor divider, soft-start capacitor, and input/output capacitors are required for basic operation.
What is the function of the PG (Power-Good) pin on NCP3126ADR2G?
On the NCP3126ADR2G, the PG pin is an open-drain output that goes high-impedance when the FB voltage reaches 90% of target and remains within ±10% regulation. It must be pulled up externally (e.g., to 3.3V) and signals host systems when the output is valid, enabling safe processor reset sequencing and system power management.
Can NCP3126ADR2G operate with input voltage below 4.5V?
No-the NCP3126ADR2G has a minimum specified input voltage of 4.5V due to internal gate drive requirements for its integrated MOSFETs. Operation below this threshold may result in unstable regulation, premature UVLO activation, or failure to start; it is not characterized or guaranteed for sub-4.5V use.
Is the exposed thermal pad on NCP3126ADR2G electrically connected to any internal node?
No-the exposed thermal pad on the NCP3126ADR2G is internally connected only to the die substrate (GND potential) and must be soldered to a PCB ground plane. It is not tied to VIN, SW, or any signal node; correct grounding ensures both thermal performance and EMI suppression per the onsemi package drawing PS-001B.
NCP3126ADR2G 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:
- 3A
- Frequency - Switching:
- 350kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
NCP3126ADR2G FAQ
1.How can I place an order for NCP3126ADR2G through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP3126ADR2G 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 NCP3126ADR2G reliable?
The price and inventory of NCP3126ADR2G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP3126ADR2G is usually 5 days.
3.What payment methods are accepted for NCP3126ADR2G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP3126ADR2G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP3126ADR2G?
NCP3126ADR2G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP3126ADR2G 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 NCP3126ADR2G?
For technical support, including NCP3126ADR2G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP3126ADR2G requirements.
6.How does Aetrix verify that NCP3126ADR2G is sourced from the original manufacturer or authorized distributors?
All NCP3126ADR2G 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 NCP3126ADR2G meets industry standards.
7.What is the process for return or replacement of NCP3126ADR2G?
All NCP3126ADR2G units undergo pre-shipment inspection (PSI). If there is an issue with NCP3126ADR2G, 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 NCP3126ADR2G part is unused and in its original packaging.
Return procedure for NCP3126ADR2G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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