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Monolithic Power Systems Inc. MP4321GDE-Z
- Part No.:
- MP4321GDE-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- 12-PowerVFQFN
- Datasheet:
-
MP4321GDE-Z.pdf
- Description:
- IC REG BUCK ADJ 1A 12QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,470
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Product details
Overview
MP4321GDE-Z from Monolithic Power Systems is a 36V, 1A synchronous step-down DC/DC converter with integrated 70mΩ/50mΩ MOSFETs, configurable 350kHz–2.5MHz switching frequency, 42V load dump tolerance, and 1μA shutdown current. It operates from 3.3V to 36V input, delivers adjustable or fixed output (0.8V–0.95×VIN), and supports automotive cold-crank down to 3.1V VIN - deployed in USB chargers and aftermarket automotive power rails.
For engineers reviewing the MP4321GDE-Z datasheet, MP4321GDE-Z pinout, MP4321GDE-Z application, or MP4321GDE-Z equivalent, key selection criteria include its QFN-12 (2mm×3mm) wettable flank package, CISPR25 Class 5 EMI compliance, AAM light-load efficiency mode, and PG open-drain status signal with ±1.5% hysteresis.
Technical Context
The MP4321GDE-Z uses peak current-mode control with frequency foldback at startup to prevent inductor current runaway. Its integrated high-side and low-side MOSFETs enable up to 1A continuous output with thermal shutdown (160°C–185°C trip) and over-current protection in hiccup mode.
It implements Advanced Asynchronous Modulation (AAM) for light-load efficiency, supports low-dropout operation during cold crank via high-duty-cycle mode, and features frequency spread spectrum (±10%) and symmetric VIN pinout to meet CISPR25 Class 5 radiated/conducted emissions requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 36V - supports wide automotive battery range including cold-crank (min 3.1V post-startup) |
| Output Current | 1A continuous - sufficient for USB PD sink rails and infotainment subsystems |
| Switching Frequency | 350kHz to 2.5MHz - programmable via external resistor on FREQ pin for EMI optimization |
| Quiescent Current | 20μA in sleep mode - extends battery life in always-on vehicle modules |
| Load Dump Tolerance | 42V - meets ISO16750-2 pulse 5a for automotive transient immunity |
| Feedback Reference | 0.8V ±1% - enables precise output regulation across temperature (-40°C to +125°C) |
| Power Good Threshold | 94.5% to 105.5% of VREF - provides accurate output voltage monitoring with 1.5% hysteresis |
Pinout & Package
MP4321GDE-Z is housed in a QFN-12 (2mm × 3mm) package with wettable flanks for automated optical inspection (AOI) and enhanced solder joint reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 11 PGND | Power ground | Dual ground pins minimize ground loop impedance; connect directly to thermal pad and bulk capacitor |
| 2, 10 VIN | Main input supply | Two parallel VIN pins reduce trace resistance and improve current sharing for high-transient environments |
| 3 BOOT | Bootstrap supply | Drives high-side MOSFET gate; requires 0.1µF ceramic capacitor between BOOT and SW |
| 4 FREQ | Frequency setting | Resistor-to-ground sets fSW (350kHz–2.5MHz); enables EMI tuning without changing inductors |
| 5 VCC | Bias regulator output | Internal LDO supplies control circuitry; requires ≥1µF decoupling to AGND |
| 6 AGND | Analog ground | Separate ground reference for feedback and error amplifier; must be star-connected to PGND |
| 7 FB | Feedback input | 0.8V reference node; connects to resistive divider for adjustable outputs or directly to VOUT for fixed versions |
| 8 PG | Power good indicator | Open-drain output signals valid regulation (94.5–105.5% VREF); requires external pull-up |
| 9 EN | Enable control | Logic-level input (1.02V rising threshold); no internal pull-up; must not float |
| 12 SW | Switch node | Connection point between HS-FET source and LS-FET drain; critical for layout and EMI filtering |
Key Features
| Feature | Design Value |
|---|---|
| 42V Load Dump Tolerance | Withstands ISO16750-2 Pulse 5a transients without external TVS, reducing BOM count |
| Wettable Flank QFN-12 | Enables automated AOI of solder joints - critical for automotive AEC-Q200-compliant manufacturing |
| Frequency Spread Spectrum (FSS) | ±10% modulation at 15kHz reduces peak EMI by >10dB, easing CISPR25 Class 5 certification |
| MeshConnect™ Flip-Chip | Reduces parasitic inductance and improves thermal conduction vs. wire-bond packages |
| Low-Dropout (LDO) Mode | Maintains regulation down to VIN = VOUT + 0.3V during cold-crank, avoiding system brownout |
Applications
| USB Chargers | Aftermarket Automotive Modules |
|---|---|
Use Scenario: Compact 5V/3.3V power rail for OBD-II dongles, dashcams, and wireless car adapters. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated output from 12V vehicle bus with transient immunity. Use Value: 42V load dump tolerance eliminates need for external TVS; 1μA shutdown current extends battery runtime in parked-state accessories. | Use Scenario: Power management in radar detectors, HUD controllers, and smart mirrors with extended temperature operation. IC Role / Device Role / Timing Role: High-reliability DC/DC converter supporting -40°C to +125°C junction temperature and cold-crank conditions. Use Value: 3.1V minimum operating VIN and high-duty-cycle mode ensure uninterrupted operation during engine start. |
| Battery-Powered Systems | Industrial Telematics Units |
Use Scenario: Long-life power solution for portable diagnostic tools and handheld scanners powered by Li-ion or lead-acid batteries. IC Role / Device Role / Timing Role: Efficient step-down regulator with ultra-low quiescent current for standby and active modes. Use Value: 20μA sleep-mode IQ and AAM light-load modulation extend battery service life by >30% vs. standard PWM-only converters. | Use Scenario: Power conversion in fleet-tracking devices mounted in engine bays or under-dash enclosures. IC Role / Device Role / Timing Role: EMI-optimized buck converter meeting CISPR25 Class 5 for radiated/conducted emissions in noisy vehicle environments. Use Value: Symmetric VIN pinout and FSS modulation reduce layout sensitivity and simplify EMC debug cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM61480RQWR | 42V max input, 8A output, 2.1MHz fSW, 15μA IQ - larger package (QFN-16), higher current rating | Targets higher-power ADAS ECUs; lacks wettable flanks and CISPR25 Class 5 validation | Select when >1A output or lower thermal resistance is required; verify layout for higher current loops |
| TPS62810QWRVRQ1 | 6V max input, 1A output, 2.25MHz fSW, 1.2μA ISD - automotive-grade but narrow VIN range (2.7–6V) | Suitable only for post-LDO 5V rails; cannot replace MP4321GDE-Z in direct battery-fed designs | Use only in low-input-voltage subsystems; not viable for 12V/24V direct connection |
Compared with LM61480RQWR and TPS62810QWRVRQ1, MP4321GDE-Z uniquely balances 36V input capability, 42V transient robustness, wettable-flank manufacturability, and Class 5 EMI compliance in a 2mm×3mm footprint - making it optimal for space-constrained, cost-sensitive automotive accessories.
Availability
MP4321GDE-Z is available at Aetrix Electronics and suitable for USB chargers, aftermarket automotive modules, and battery-powered systems requiring stable component supply, automotive-grade reliability, and rapid prototyping support.
Supply support for MP4321GDE-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 power management ICs, with design centers in the US, China, and Taiwan.
The MP4321 product line targets cost-sensitive, space-constrained automotive aftermarket and industrial applications requiring robust transient handling, low IQ, and EMI-compliant integration - delivered in ultra-compact QFN packages.
FAQ
What is the minimum input voltage required to start up the MP4321GDE-Z?
The MP4321GDE-Z has a VIN UVLO rising threshold of 3.65V typical (3.4V min), so startup requires ≥3.4V. After startup, it sustains regulation down to 3.1V VIN - enabling operation during automotive cold-crank events where battery voltage dips below 6V.
Does MP4321GDE-Z support fixed-output voltage configurations?
Yes - MP4321GDE-Z is the adjustable-output version, but MPS offers fixed-output variants (e.g., MP4321AGDE-Z for 3.3V, MP4321BGDE-Z for 5V). Fixed versions tie FB internally to VOUT, eliminating external resistors while retaining all other features including PG, FREQ programming, and thermal protection.
How is the switching frequency set, and what resistor value yields 2.2MHz?
Switching frequency is set by a resistor from FREQ to AGND. Per datasheet Figure 27, RFREQ = 15kΩ yields 2.2MHz typical (1.98–2.42MHz range). The relationship is inverse-logarithmic; values outside 10kΩ–100kΩ may cause deviation or instability.
What thermal performance can be expected in a 2-layer PCB layout?
On a 2-layer board (1oz copper), θJA is ~100°C/W (vs. 60°C/W on 4-layer JESD51-7). At 1A load and 12V input, junction rise exceeds 100°C - thus a 4-layer board with thermal vias to internal ground planes is recommended for full 1A continuous operation at +85°C ambient.
Is the PG pin actively driven or open-drain, and what pull-up voltage is supported?
The PG pin is strictly open-drain. It requires an external pull-up resistor to any supply ≤5.5V (e.g., VCC or system 3.3V/5V rail). The PG low-state voltage is ≤0.3V at 1mA sink, and it asserts high when VOUT is within 94.5–105.5% of the feedback reference voltage.
Can MP4321GDE-Z operate without the BOOT capacitor?
No - the BOOT capacitor (0.1µF X7R ceramic) between BOOT and SW is mandatory. Without it, the high-side MOSFET gate driver cannot generate sufficient gate voltage, causing immediate failure to regulate and potential shoot-through damage to internal FETs.
Does the device include over-temperature protection, and how does it behave?
Yes - thermal shutdown activates at TJ = 160–185°C (typical 175°C) with 20°C hysteresis. When triggered, the converter halts switching, cools passively, and resumes operation automatically once TJ falls below ~155°C - no latch or external reset required.
MP4321GDE-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 12-PowerVFQFN
- 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):
- 3.3V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 34.2V
- Current - Output:
- 1A
- Frequency - Switching:
- 350kHz ~ 2.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 12-QFN (2x3)
MP4321GDE-Z FAQ
1.How can I place an order for MP4321GDE-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP4321GDE-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 MP4321GDE-Z reliable?
The price and inventory of MP4321GDE-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP4321GDE-Z is usually 5 days.
3.What payment methods are accepted for MP4321GDE-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP4321GDE-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP4321GDE-Z?
MP4321GDE-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP4321GDE-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 MP4321GDE-Z?
For technical support, including MP4321GDE-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP4321GDE-Z requirements.
6.How does Aetrix verify that MP4321GDE-Z is sourced from the original manufacturer or authorized distributors?
All MP4321GDE-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 MP4321GDE-Z meets industry standards.
7.What is the process for return or replacement of MP4321GDE-Z?
All MP4321GDE-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP4321GDE-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 MP4321GDE-Z part is unused and in its original packaging.
Return procedure for MP4321GDE-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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