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Monolithic Power Systems Inc. MP2351DQ-LF-Z
- Part No.:
- MP2351DQ-LF-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- 10-VFDFN Exposed Pad
- Datasheet:
-
MP2351DQ-LF-Z.pdf
- Description:
- IC REG BUCK ADJ 1.5A 10QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,006
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Product details
Overview
MP2351DQ-LF-Z from Monolithic Power Systems is a monolithic synchronous step-down DC/DC converter with integrated 0.18Ω high-side MOSFET and 10Ω low-side switch, delivering 1.5A continuous output current across 4.75V–23V input range, fixed 1.4MHz switching frequency, and adjustable output from 1.23V to 16V - used in DSL modems for compact, efficient local 3.3V/5V rail generation.
For engineers reviewing the MP2351DQ-LF-Z datasheet, MP2351DQ-LF-Z pinout, MP2351DQ-LF-Z application, or MP2351DQ-LF-Z equivalent, key selection criteria include thermal shutdown threshold (160°C), cycle-by-cycle overcurrent protection (2.4–5.2A), feedback voltage accuracy (±2.7% at 1.23V), and QFN-10 package compatibility with ceramic capacitor stability.
Technical Context
The MP2351DQ-LF-Z implements current-mode control with transconductance error amplifier (GEA = 500–1100 μA/V) and slope-compensated peak-current sensing, enabling fast transient response and stable loop behavior with minimal external compensation components. Its internal 1.23V bandgap reference feeds the FB pin, and COMP pin serves as both error amplifier output and current comparator input.
It integrates dual MOSFETs (RDS(ON) = 0.18Ω / 10Ω), bootstrap gate drive (BS pin), programmable UVLO (2.37–2.62V rising threshold), and SYNC input supporting external clock synchronization up to 2.1MHz - all operating within –40°C to +85°C junction temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.75V to 23V - supports wide industrial and telecom input rails without pre-regulation. |
| Output Current | 1.5A continuous - sufficient for powering FPGA I/O banks, Ethernet PHYs, or microcontroller cores. |
| Switching Frequency | Fixed 1.4MHz (±17.9%) - enables small external inductors & capacitors; avoids AM radio band. |
| Feedback Voltage | 1.230V ±0.035V - sets output via resistor divider; accuracy directly impacts VOUT regulation error. |
| Shutdown Current | 20μA - ensures ultra-low power loss during system sleep or standby modes. |
| Thermal Shutdown | 160°C - protects against sustained overload or poor PCB thermal design. |
| Current Limit | 2.4A to 5.2A (cycle-by-cycle) - scales with duty cycle; prevents MOSFET failure under short-circuit. |
Pinout & Package
MP2351DQ-LF-Z uses a thermally enhanced 3mm × 3mm QFN-10 package with exposed pad (connected to GND) for low θJA = 50°C/W. Pin 1 identification corner marked on top surface; pins are not internally connected except as defined below.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3 NC | No Connect | Unused die pads; must remain floating - no routing or soldering required. |
| 2 BS | Bootstrap Supply | Connects external 10nF capacitor between SW and BS to generate gate drive voltage > VIN for high-side MOSFET. |
| 4 IN | Power Input | Accepts 4.75–23V unregulated supply; requires local 10μF low-ESR ceramic input capacitor. |
| 5 SW | Switch Node | Drives external inductor; connects to IN (high-side ON) or GND (low-side ON); high dv/dt node. |
| 6 GND | Power Ground | Main return path; exposed pad must be soldered to large PCB ground plane for thermal & EMI performance. |
| 7 FB | Feedback Input | Senses output voltage via resistive divider; internal 1.23V reference sets regulation point. |
| 8 COMP | Compensation Node | Error amplifier output; external RC network here stabilizes control loop and sets phase margin. |
| 9 EN | Enable / UVLO | Active-high enable; 2.5V typical turn-on threshold; supports programmable undervoltage lockout. |
| 10 SYNC | Frequency Sync Input | Accepts external clock (1.6–2.1MHz); internal 11kΩ pull-down allows open-circuit disable. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power Stage | 0.18Ω high-side + 10Ω low-side MOSFETs eliminate external switch count and layout complexity. |
| Ceramic-Capacitor Stable | Operates with low-ESR ceramic output caps - reduces BOM cost and board area vs. tantalum/electrolytic. |
| Fast Transient Response | Current-mode architecture with transconductance error amplifier enables <10μs load-step recovery. |
| Programmable Protection | UVLO threshold, sync input, and frequency foldback during short-circuit enhance system-level robustness. |
| High Efficiency | Up to 93% at mid-load - minimizes thermal stress in space-constrained DSL and battery-charger applications. |
Applications
| DSL Modem Power Rails | Battery Charger Pre-Regulator |
|---|---|
|
Use Scenario: Generating clean 3.3V/5V supplies from 12V or 19V adapter input in residential DSL/Cable modems. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, regulated DC rails for PHY, MCU, and memory subsystems. Use Value: Fixed 1.4MHz operation avoids audible noise; QFN-10 footprint saves PCB area in dense modem modules. |
Use Scenario: Stepping down variable wall-adapter or USB-PD input (up to 23V) before linear charging ICs. IC Role / Device Role / Timing Role: Efficient pre-regulator reducing power dissipation in downstream linear chargers. Use Value: Wide 4.75–23V input accommodates multiple adapters; 1.5A output supports fast-charge protocols. |
| Distributed Telecom Power | Pre-Regulator for LDOs |
|
Use Scenario: Local point-of-load conversion in multi-rail telecom line cards requiring 2.5V/3.3V from 48V intermediate bus. IC Role / Device Role / Timing Role: High-voltage-input buck converter feeding downstream converters or LDOs. Use Value: 23V max input rating enables direct use after passive front-end filtering; thermal shutdown prevents field failures. |
Use Scenario: Providing stable 3.3V or 5V input to low-noise LDOs powering RF or analog signal chains. IC Role / Device Role / Timing Role: Efficient intermediate regulator minimizing dropout and heat in LDO input stage. Use Value: 1.23V feedback reference enables precise output setting; low 20μA shutdown current preserves battery life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2359DJ-LF-Z | Same 1.4MHz frequency, but 2A output rating and 0.12Ω RDS(ON); QFN-12 package. | Higher current capability suits 5V@2A systems; larger package requires layout revision. | Select when >1.5A load margin or lower conduction loss is critical. |
| TPS54331DR | 3A output, 570kHz switching, external MOSFETs; SOIC-8 package; no integrated low-side switch. | Lower frequency eases EMI filtering but increases inductor size; requires external FETs and driver. | Select when higher output current or discrete FET control is needed; not drop-in compatible. |
Compared with MP2351DQ-LF-Z, MP2359DJ-LF-Z offers higher current headroom at same frequency but larger footprint, while TPS54331DR provides greater flexibility with external FETs at the cost of added component count and reduced integration.
Availability
MP2351DQ-LF-Z is available at Aetrix Electronics and suitable for DSL modems, battery charger pre-regulators, and distributed telecom power systems requiring stable component supply, lead-free compliance, and QFN-10 thermal performance.
Supply support for MP2351DQ-LF-Z 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
Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, founded in 1997 and headquartered in Kirkland, Washington.
The MP2351 belongs to MPS's integrated DC/DC converter product line, designed for space-constrained, high-efficiency point-of-load applications in networking, computing, and industrial equipment where small size and reliability are critical.
FAQ
What is the minimum recommended output capacitance for stable operation?
The MP2351DQ-LF-Z is stable with low-ESR ceramic capacitors ≥10μF. Typical designs use 22μF X5R/X7R ceramics with ≤5mΩ ESR. Larger values improve ripple suppression but require re-evaluation of compensation zero placement at the COMP pin.
Can the MP2351DQ-LF-Z synchronize to an external clock below 1.4MHz?
No - the SYNC pin accepts only external clocks between 1.6MHz and 2.1MHz per datasheet specifications. Attempting synchronization below 1.6MHz may cause erratic switching or loss of regulation due to internal comparator timing constraints.
Is the BS pin required to be connected in all applications?
Yes - the BS pin must be connected to a 10nF capacitor between SW and BS to provide gate drive voltage for the high-side MOSFET. Omitting this connection prevents high-side switch turn-on and results in no output regulation.
What happens during a short-circuit condition at the output?
When FB voltage drops below 700mV, the frequency foldback circuit reduces oscillator frequency to 180kHz, lowering average power dissipation. Simultaneously, cycle-by-cycle current limiting activates, clamping peak inductor current to prevent damage.
Does the EN pin have an internal pull-up?
No - the EN pin has no internal pull-up. It features 1.15–1.50μA internal pull-down current. For automatic startup, leave EN unconnected; for controlled enable, drive it above 2.62V with an external source or resistor divider from VIN.
How does the exposed thermal pad affect PCB layout?
The exposed pad (Pin 6 GND) must be soldered to a solid copper thermal pad ≥100mm² connected to internal/external ground planes via ≥4 thermal vias (0.3mm diameter). Failure to do so raises junction temperature by >30°C under full load, risking thermal shutdown.
What is the maximum achievable output voltage accuracy over temperature and line?
Over –40°C to +85°C and 4.75–23V input, output voltage accuracy is dominated by FB pin reference tolerance (±2.7% at 1.23V) and resistor divider ratio drift. With 0.5% resistors, total VOUT error remains within ±3.5% across full operating range.
MP2351DQ-LF-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 10-VFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.75V
- Voltage - Input (Max):
- 23V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 16V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 1.4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-QFN (3x3)
MP2351DQ-LF-Z FAQ
1.How can I place an order for MP2351DQ-LF-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP2351DQ-LF-Z 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 MP2351DQ-LF-Z reliable?
The price and inventory of MP2351DQ-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP2351DQ-LF-Z is usually 5 days.
3.What payment methods are accepted for MP2351DQ-LF-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP2351DQ-LF-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP2351DQ-LF-Z?
MP2351DQ-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP2351DQ-LF-Z 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 MP2351DQ-LF-Z?
For technical support, including MP2351DQ-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP2351DQ-LF-Z requirements.
6.How does Aetrix verify that MP2351DQ-LF-Z is sourced from the original manufacturer or authorized distributors?
All MP2351DQ-LF-Z 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 MP2351DQ-LF-Z meets industry standards.
7.What is the process for return or replacement of MP2351DQ-LF-Z?
All MP2351DQ-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP2351DQ-LF-Z, 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 MP2351DQ-LF-Z part is unused and in its original packaging.
Return procedure for MP2351DQ-LF-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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