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Monolithic Power Systems Inc. MP9943AGQ-Z
- Part No.:
- MP9943AGQ-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- 8-VDFN
- Datasheet:
-
MP9943AGQ-Z.pdf
- Description:
- IC REG BUCK ADJ 3A 8QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,505
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Product details
Overview
MP9943AGQ-Z from Monolithic Power Systems is a high-frequency, synchronous step-down DC/DC converter with integrated 85mΩ/55mΩ MOSFETs, delivering up to 3A peak output current across a 4V–36V input range. It features 410kHz fixed switching frequency, power good (PG) indicator, and force-CCM operation-designed for automotive cold-crank and industrial distributed power systems where wide VIN and reliable rail generation are critical.
For engineers reviewing the MP9943AGQ-Z datasheet, MP9943AGQ-Z pinout, MP9943AGQ-Z application, or MP9943AGQ-Z equivalent, this page delivers verified electrical parameters, QFN-8 package layout guidance, thermal shutdown thresholds (170°C), PG delay timing (90μs), and real-world design constraints including BST resistor recommendation (20Ω) and FB reference voltage (792mV).
Technical Context
The MP9943AGQ-Z operates in peak-current-mode control with internal 0.792V feedback reference and optimized compensation, enabling stable regulation without external loop components. Its synchronous rectification and low RDS(ON) MOSFETs minimize conduction loss across load currents from light-load to 3A peak.
It supports external clock synchronization (200kHz–2.2MHz), implements fold-back frequency reduction during short-circuit faults (70–130kHz), and integrates a dedicated bootstrap charging circuit with UVLO (2.2V) for the high-side driver-ensuring robust gate drive under high-duty-cycle conditions like automotive cold-crank (≥92% DMAX).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V continuous - supports 12V/24V automotive rails and industrial 24V/36V supplies without pre-regulation. |
| Output Current | 3A peak - sufficient for powering microcontrollers, sensors, and interface ICs in compact embedded systems. |
| Switching Frequency | 410kHz typical - balances EMI performance and inductor size; adjustable via EN/SYNC pin from 200kHz to 2.2MHz. |
| Feedback Reference | 792mV ±14mV - sets precise output voltage using external resistor divider; enables 0.8V minimum VOUT. |
| Power Good Threshold | 90% of VFB rising / 84% falling - provides accurate rail monitoring with 6% hysteresis and 90μs delay for sequenced power-up. |
| Thermal Shutdown | 170°C activation / 140°C recovery - protects against sustained overload while allowing automatic restart after cooling. |
| Current Limit | 5.5A typical - ensures safe operation during transient overloads and short-circuit events with hiccup-mode recovery. |
Pinout & Package
MP9943AGQ-Z is housed in a thermally enhanced QFN-8 (3mm × 3mm) package with exposed thermal pad, optimized for high-power density PCB layouts requiring minimal board area and efficient heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FB | Feedback Input | Connects to resistor divider tap; regulates output by comparing against 0.792V internal reference; triggers fold-back below 660mV during fault. |
| 2 VCC | Bias Supply | Internal 5V regulator output; powers control circuitry; requires 0.1–0.22μF ceramic decoupling close to pin. |
| 3 EN/SYNC | Enable & Clock Input | Digital enable (1.4V threshold); accepts external clock (200kHz–2.2MHz) to synchronize switching; includes 500kΩ pull-down. |
| 4 BST | Bootstrap Supply | Drives high-side MOSFET gate; requires capacitor between BST and SW; 20Ω series resistor recommended to suppress SW spikes. |
| 5 GND | System Ground | Reference for output voltage and internal circuits; must connect directly to thermal pad and large copper pour for thermal and noise integrity. |
| 6 SW | Switch Node | High-frequency switching output node; connects to inductor and BST capacitor; requires wide, low-inductance PCB trace. |
| 7 IN | Input Supply | Primary power input (4–36V); requires local 22μF + 1μF ceramic decoupling; RMS current rating ≥1.5A. |
| 8 PG | Power Good Output | Open-drain status signal; pulled low at startup and during fault (UVLO, thermal shutdown, EN low); rises after VFB > 90% × 0.792V. |
Key Features
| Feature | Design Value |
|---|---|
| Wide Input Range (4V–36V) | Enables direct connection to 12V/24V vehicle batteries and industrial power rails without intermediate regulators. |
| Synchronous Rectification | Reduces conduction loss vs. diode-based buck converters-critical for >85% efficiency at 3A loads. |
| Force CCM Mode | Maintains continuous conduction across full load range, eliminating audible noise and improving light-load regulation. |
| Integrated Power MOSFETs | 85mΩ HS / 55mΩ LS RDS(ON) minimizes die temperature rise and simplifies BOM by eliminating external switches. |
| Automotive Cold-Crank Support | 95% max duty cycle allows regulation down to 3.6V input-essential for engine-start transients in 12V systems. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering display controllers, audio codecs, and CAN transceivers in head units during engine cranking. IC Role / Device Role / Timing Role: Primary 5V/3.3V rail generator with cold-crank support and PG sequencing. Use Value: Maintains regulated output down to 3.6V input and signals system controller via PG pin when rail is stable. |
Use Scenario: Generating isolated 3.3V logic supply for digital I/O channels in modular PLC backplanes. IC Role / Device Role / Timing Role: Compact, high-efficiency point-of-load converter with hiccup-mode short-circuit protection. Use Value: Delivers 3A peak current in <10mm² footprint while limiting fault energy during field wiring errors. |
| Multi-Function Printer (MFP) Engine Control | Distributed Telecom Power |
|
Use Scenario: Supplying stepper motor drivers and sensor interfaces in MFP paper path subsystems. IC Role / Device Role / Timing Role: High-current, low-noise buck regulator synchronized to system clock to reduce EMI coupling. Use Value: 410kHz base frequency with external sync capability enables deterministic noise placement away from imaging sensors. |
Use Scenario: Local 5V rail generation for remote PHYs and management controllers in 48V telecom shelf systems. IC Role / Device Role / Timing Role: Wide-VIN step-down stage converting -36V to +5V (via auxiliary bias) with thermal-aware shutdown. Use Value: 170°C thermal shutdown and 2.27W θJA = 55°C/W rating ensure reliability in confined, fanless enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2451DT-LF-Z | Lower 2.5A peak current, 2MHz max switching frequency, no PG pin, 3.3V–36V input. | Lacks power-good signaling and cold-crank duty cycle; suited for space-constrained, non-sequenced rails. | Select when PG functionality and >92% duty cycle are not required, and higher fSW reduces inductor size. |
| LM61480RQR | TI part with 8A rating, 2.1MHz fSW, PMBus interface, and adjustable soft-start; larger 16-pin QFN. | Targets high-end industrial systems needing telemetry and dynamic configuration-not drop-in replacement. | Choose only if programmability, higher current, or digital control justify redesign and cost increase. |
Compared with MP2451DT-LF-Z and LM61480RQR, MP9943AGQ-Z uniquely balances 3A peak delivery, PG signaling, cold-crank readiness, and QFN-8 compactness-making it optimal for cost-sensitive, thermally constrained automotive and industrial modules where rail integrity and sequencing matter.
Availability
MP9943AGQ-Z is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and multi-function printer engine control requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for MP9943AGQ-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, with focus on efficiency, integration, and thermal robustness.
The MP9943A belongs to MPS's high-voltage synchronous buck converter product line, engineered for automotive, industrial, and consumer applications demanding wide-input operation, compact footprint, and reliable fault handling.
FAQ
What is the minimum input voltage required for MP9943AGQ-Z to start switching?
The MP9943AGQ-Z has an under-voltage lockout (UVLO) rising threshold of 3.5V. It begins switching only when VIN exceeds this value, ensuring stable internal regulator operation before enabling the power stage. The falling threshold is 3.3V, providing 200mV hysteresis to prevent oscillation near the trip point.
Can MP9943AGQ-Z operate in forced continuous conduction mode (FCCM) at light loads?
Yes-MP9943AGQ-Z supports Force CCM mode, maintaining constant switching frequency and inductor current flow even at zero load. This eliminates mode transitions that cause output voltage ripple and audible noise, making it ideal for noise-sensitive applications like audio subsystems.
How is the power good (PG) signal timed relative to output voltage stabilization?
The PG pin asserts high 90μs after VFB exceeds 90% of the 792mV reference (i.e., ~713mV). It deasserts low when VFB falls below 84% (~665mV), with 6% hysteresis. PG remains low during startup, thermal shutdown, or EN/SYNC deactivation-providing unambiguous system-level power sequencing.
What is the recommended BST capacitor value and why is a 20Ω resistor advised?
A 0.1μF to 1μF ceramic capacitor is recommended between BST and SW pins. A 20Ω resistor in series limits inrush current into the BST cap, reducing high-frequency ringing and voltage spikes on the SW node-critical for EMI compliance and MOSFET gate driver reliability.
Does MP9943AGQ-Z require external compensation components for stability?
No-MP9943AGQ-Z features an internally compensated error amplifier optimized for common output capacitor types (ceramic, tantalum, electrolytic). Stability is maintained across a wide range of capacitance and ESR values without external compensation networks, simplifying design and reducing BOM count.
What thermal derating applies above +25°C ambient?
With θJA = 55°C/W on a 4-layer PCB, the maximum allowable power dissipation decreases linearly: PDMAX = (150°C − TA) / 55. At 85°C ambient, PDMAX drops to ~1.18W-requiring careful layout (thermal pad, vias) and potential current derating to maintain junction temperature ≤125°C.
Is MP9943AGQ-Z qualified for automotive AEC-Q100 stress testing?
No-the MP9943AGQ-Z is not AEC-Q100 qualified. It is rated for industrial temperature range (−40°C to +125°C junction), but lacks automotive-specific qualification. For AEC-Q100 applications, consider MPS's automotive-grade variants such as MPQ9843A.
MP9943AGQ-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 8-VDFN
- 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):
- 4V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28.5V
- Current - Output:
- 3A
- Frequency - Switching:
- 410kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-QFN (3x3)
MP9943AGQ-Z FAQ
1.How can I place an order for MP9943AGQ-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP9943AGQ-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 MP9943AGQ-Z reliable?
The price and inventory of MP9943AGQ-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP9943AGQ-Z is usually 5 days.
3.What payment methods are accepted for MP9943AGQ-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP9943AGQ-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP9943AGQ-Z?
MP9943AGQ-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP9943AGQ-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 MP9943AGQ-Z?
For technical support, including MP9943AGQ-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP9943AGQ-Z requirements.
6.How does Aetrix verify that MP9943AGQ-Z is sourced from the original manufacturer or authorized distributors?
All MP9943AGQ-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 MP9943AGQ-Z meets industry standards.
7.What is the process for return or replacement of MP9943AGQ-Z?
All MP9943AGQ-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP9943AGQ-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 MP9943AGQ-Z part is unused and in its original packaging.
Return procedure for MP9943AGQ-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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