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onsemi FAN2315MPX
- Part No.:
- FAN2315MPX
- Manufacturer:
- onsemi
- Package:
- 34-PowerTFQFN
- Datasheet:
-
FAN2315MPX.pdf
- Description:
- IC REG BUCK ADJ 15A 34PQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,870
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Product details
Overview
FAN2315MPX from ON Semiconductor (formerly Fairchild) is a 15 A synchronous buck regulator IC designed for high-efficiency DC-DC conversion in server, telecom, and notebook power rails. It operates from 4.5 V to 18 V input, delivers 0.6–5.5 V output with ±1% reference accuracy, supports programmable 200 kHz–1 MHz switching frequency, and integrates internal boot diode and thermal shutdown.
For engineers reviewing the FAN2315MPX datasheet, pinout, applications, or equivalent options, this page provides verified technical context, validated pin functions, confirmed protection features (OVP/UVP/OCP/OTP), real-world efficiency data (>96% peak), and selection guidance for high-current POL applications requiring ultrasonic PFM mode and stable light-load performance.
Technical Context
The FAN2315MPX employs constant on-time (COT) control with VIN feed-forward, enabling fixed-frequency operation in CCM and variable-frequency PFM in DCM-ensuring excellent line/load transient response without loop compensation. Its modulator uses a 2.2 pF internal capacitor and frequency-setting resistor (RFREQ) to generate tON proportional to VOUT/VIN.
Protection architecture includes dual-level over-voltage detection (108–115% and 118–125% of VREF), valley-current limiting via ILIM pin, hysteresis-based thermal shutdown (155°C trip, 140°C restart), and open-drain PGOOD with 0.82–2.03 ms soft-start delay. The device forces PFM during soft-start and pre-bias startup to prevent output discharge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5 V to 18 V - Supports wide-input industrial and computing rails including 5 V, 12 V, and 15 V bus systems. |
| Output Current | 15 A continuous - Delivers full rated current at TJ ≤ 125°C on standard 4-layer PCB (7 cm × 7 cm, 1 oz copper). |
| Reference Accuracy | ±1% over –40°C to +125°C - Ensures tight output regulation across temperature without external trimming. |
| Switching Frequency | 200 kHz to 1 MHz - Programmable via resistor on FREQ pin; enables optimization for size (high-f), efficiency (mid-f), or EMI (low-f). |
| Efficiency Peak | >96% - Achieved at mid-load under 12 VIN/1.2 VOUT conditions; enabled by synchronous rectification and low RDS(on) drivers. |
| Protection Features | OVP (dual-level), UVP, OCP (valley-current), OTP (155°C), PGOOD - Comprehensive fault coverage with automatic recovery or latched shutdown per condition. |
| Soft-Start Control | Programmable via external capacitor - Internal 10 µA current source enables monotonic ramp; clamp drops to 40 mV during overload for controlled recovery. |
Pinout & Package
Package: 34-lead PQFN, 5.5 mm × 5.0 mm, exposed thermal pad - Optimized for high-power density and thermal dissipation (θJA = 35°C/W on 4-layer board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN (P2, Pins 5–11) | Power input for high-side MOSFET | High-current path for input supply; multiple parallel pads reduce IR drop and improve thermal conduction. |
| SW (P3, Pins 2, 12–17, 22) | Switching node | Junction of HS/LS MOSFETs; requires low-inductance layout to minimize ringing and EMI. |
| BOOT (Pin 3) | High-side gate driver supply | Capacitor from BOOT to SW supplies charge for HS turn-on; internal diode recharges it from PVCC during freewheeling. |
| ILIM (Pin 24) | Valley current limit set point | Resistor between ILIM and SW programs current threshold; supports adjustable OCP without external sense resistor. |
| FB (Pin 27) | Feedback input | Monitors output voltage divider; ±1% reference enables precise regulation; supports ripple injection for ceramic-cap stability. |
| PGOOD (Pin 30) | Open-drain power-good indicator | Pulls low during UV/OV/OT faults; 125 Ω pull-down ensures fast assertion (<2 ms delay) for system sequencing. |
| EN (Pin 29) | Enable input | TTL-compatible (0.8 V/2.0 V thresholds); supports direct logic drive; 10 µA shutdown current enables battery-backed standby. |
| FREQ (Pin 32) | Frequency programming | Resistor to AGND sets tON and fSW; open-circuit detection disables switching to prevent runaway on floating pin. |
Key Features
| Feature | Design Value |
|---|---|
| Ultrasonic PFM Mode | Clamps minimum fSW to >18 kHz - Eliminates audible noise while maintaining >90% efficiency at 10 mA load. |
| Internal Boot Diode | VF = 0.6 V @ 10 mA - Reduces BOM count and layout area; eliminates need for external bootstrap diode. |
| Pre-Bias Startup | Forces PFM and disables LS until first PWM edge - Prevents output discharge when VOUT is pre-charged, critical for hot-swap and rail sequencing. |
| Valley-Current OCP | ±10% accuracy @ 18 A - Enables precise current limiting without shunt resistor; supports scalable design across 10–20 A loads. |
| Thermal Hysteresis | 15°C (155°C trip / 140°C restart) - Prevents thermal oscillation during sustained overload; allows safe recovery without manual reset. |
Applications
| Server VR12/VR13 CPU Core Power | Telecom Base Station RF Power Amplifier Bias |
|---|---|
Use Scenario: Delivering tightly regulated 1.05 V/15 A to multi-core Xeon processors under dynamic 0–100% load steps. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing core voltage with <20 µs load transient response and PGOOD sequencing to chipset. Use Value: Constant on-time control maintains stable fSW during transients; PFM mode sustains >85% efficiency at idle, reducing cooling requirements. | Use Scenario: Generating 5 V/10 A bias for GaN RF power amplifiers in 4G/5G macro base stations with strict EMI limits. IC Role / Device Role / Timing Role: High-current POL regulator with ultrasonic PFM to avoid interference in sensitive RF front-end bands. Use Value: 200–1000 kHz programmability allows EMI tuning; dual OVP levels protect expensive RF stages from catastrophic overvoltage events. |
| Notebook NVDC System Power Rail | Enterprise Storage Controller I/O Voltage |
Use Scenario: Providing 3.3 V/12 A to SATA/NVMe controller and memory interface in thin-and-light notebooks with battery backup. IC Role / Device Role / Timing Role: Main system buck regulator supporting seamless AC/battery switchover and pre-bias startup during hot-plug events. Use Value: Pre-bias capability prevents brownout during hot insertion; <10 µA shutdown current extends battery life in S0ix sleep states. | Use Scenario: Supplying 1.8 V/15 A to high-speed SAS/SATA storage controllers in RAID enclosures with ambient temperatures up to 70°C. IC Role / Device Role / Timing Role: Thermally robust POL converter using exposed-pad PQFN package and thermal shutdown with hysteresis. Use Value: θJA = 35°C/W enables full 15 A output without heatsink; OTP restart at 140°C ensures graceful degradation rather than hard failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2451DT-LF-Z | 3 A max output, 4.5–26 V input, no PFM mode, smaller 8-pin SOIC package | Suitable for low-power auxiliary rails only; lacks valley-current OCP and thermal hysteresis | Select only for sub-5 A designs where cost and size outweigh performance requirements. |
| TPS54360BDDAR | 3.5 A max, 3.5–60 V input, integrated MOSFETs, no ultrasonic PFM, 8-pin SO PowerPAD | Better for wide-input industrial sensors; cannot scale to 15 A without external FETs | Choose when input exceeds 18 V or when integrated FETs simplify layout-but not for high-current computing rails. |
Compared with MP2451DT-LF-Z and TPS54360BDDAR, the FAN2315MPX uniquely delivers 15 A in a compact PQFN with ultrasonic PFM, valley-current limiting, and dual OVP-making it the only viable option for high-density server and telecom POL where current, efficiency, and protection integrity are non-negotiable.
Availability
FAN2315MPX is available at Aetrix Electronics and suitable for server VRMs, telecom base station power supplies, and notebook NVDC systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for FAN2315MPX 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
ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensor, and logic solutions for automotive, industrial, and computing markets.
The FAN2315MPX belongs to ON Semiconductor's high-current synchronous buck regulator product line, engineered specifically for demanding point-of-load applications in data centers, 5G infrastructure, and portable computing where efficiency, thermal resilience, and protection integrity are critical.
FAQ
What is the maximum continuous output current supported by the FAN2315MPX?
The FAN2315MPX supports 15 A continuous output current at junction temperature ≤125°C on a standard 4-layer PCB (7 cm × 7 cm, 1 oz copper). Derating applies above 125°C; the device enters thermal shutdown at 155°C with 15°C hysteresis. This rating is validated per the Recommended Operating Conditions table in the official datasheet Rev. 1.14 and confirmed by thermal characterization (ψJPCB = 2.3°C/W).
Does the FAN2315MPX require an external bootstrap diode?
No, the FAN2315MPX integrates an internal boot diode with 0.6 V forward voltage at 10 mA, eliminating the need for an external component. This reduces BOM count and PCB area while maintaining reliable high-side gate drive. The internal diode is connected between PVCC and BOOT and recharges the BOOT-to-SW capacitor during the low-side conduction phase, as documented in the Pin Definitions and Electrical Characteristics sections of the FAN2315MPX datasheet.
How does the FAN2315MPX handle startup when the output is already pre-biased?
The FAN2315MPX supports pre-bias startup by forcing PFM mode and disabling the low-side MOSFET until the first positive-going PWM edge, preventing output discharge. During this sequence, the soft-start clamp drops to 40 mV in overload conditions to enable controlled recovery. This behavior is explicitly described in the "Startup on Pre-Bias" section of the FAN2315MPX datasheet Rev. 1.14 and verified in Figure 15 waveforms.
What protection features are implemented in the FAN2315MPX?
The FAN2315MPX implements over-voltage protection (dual-level: 108–115% and 118–125% of VREF), under-voltage protection (86–92% of VREF), valley-current over-current protection (±10% accuracy), and thermal shutdown (155°C trip with 15°C hysteresis). All protections assert PGOOD low and either auto-recover (UVP, OCP, OTP) or latch (second-level OVP), as detailed in the Protection Features section and Electrical Characteristics tables of the FAN2315MPX datasheet.
Can the switching frequency of the FAN2315MPX be adjusted, and how is it programmed?
Yes, the FAN2315MPX switching frequency is programmable from 200 kHz to 1 MHz using an external resistor connected between the FREQ pin and AGND. The on-time generator uses this resistor with an internal 2.2 pF capacitor to set tON, resulting in fSW inversely proportional to RFREQ. Open-circuit detection disables switching if FREQ is left floating, ensuring safety. This programming method and range are specified in the Features list and Circuit Operation section of the FAN2315MPX datasheet Rev. 1.14.
FAN2315MPX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- TinyBuck®
- Package/Case:
- 34-PowerTFQFN
- 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):
- 15V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 15A
- Frequency - Switching:
- 200kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 34-PQFN (5.5x5)
FAN2315MPX FAQ
1.How can I place an order for FAN2315MPX through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN2315MPX 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 FAN2315MPX reliable?
The price and inventory of FAN2315MPX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN2315MPX is usually 5 days.
3.What payment methods are accepted for FAN2315MPX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN2315MPX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN2315MPX?
FAN2315MPX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN2315MPX 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 FAN2315MPX?
For technical support, including FAN2315MPX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN2315MPX requirements.
6.How does Aetrix verify that FAN2315MPX is sourced from the original manufacturer or authorized distributors?
All FAN2315MPX 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 FAN2315MPX meets industry standards.
7.What is the process for return or replacement of FAN2315MPX?
All FAN2315MPX units undergo pre-shipment inspection (PSI). If there is an issue with FAN2315MPX, 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 FAN2315MPX part is unused and in its original packaging.
Return procedure for FAN2315MPX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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