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Monolithic Power Systems Inc. MP9942AGJ-P
- Part No.:
- MP9942AGJ-P
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
MP9942AGJ-P.pdf
- Description:
- IC REG BUCK ADJ 2A TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:400
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Product details
Overview
MP9942AGJ-P from Monolithic Power Systems is a synchronous step-down DC/DC converter IC delivering 2A continuous output current with 410kHz fixed switching frequency, 4V–30V input range, and integrated 90mΩ/55mΩ MOSFETs. It features power good (PG) indication, internal soft-start, and automotive-grade cold-crank support for use in vehicle infotainment power rails.
For engineers reviewing the MP9942AGJ-P datasheet, MP9942AGJ-P pinout, MP9942AGJ-P application, or MP9942AGJ-P equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and protection behavior, and real-world design constraints including BST resistor requirements and PG timing thresholds.
Technical Context
The MP9942AGJ-P employs peak-current-mode control with internal compensation, enabling stable regulation across 0.8V–VIN×95% output voltages while maintaining fast transient response. Its 410kHz oscillator supports external synchronization from 200kHz to 2.2MHz, and fold-back frequency reduction below 100kHz activates during short-circuit faults to limit average current.
It integrates a 5V internal VCC regulator powered from VIN, bootstrap circuitry with 20Ω recommended series resistance for SW/BST spike suppression, and dual-threshold EN/SYNC logic (1.15V rising / 1.05V falling) with 150mV hysteresis. Thermal shutdown triggers at 170°C with 30°C hysteresis, and over-current protection operates in hiccup mode below 84% of FB reference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 30V continuous; withstands 36V transients - enables direct connection to automotive battery rails during load dump. |
| Output Current | 2A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in compact embedded systems. |
| Switching Frequency | 410kHz fixed, synchronizable 200kHz–2.2MHz - balances EMI control, inductor size, and efficiency in space-constrained designs. |
| Feedback Reference | 792mV ±12mV - sets precise output voltage via external resistor divider; enables 0.8V minimum adjustable output. |
| Power Good Threshold | Rising at 90% of VFB (±3.5%), falling at 84% (±3.5%) - provides reliable system-level power sequencing with 90μs typical delay. |
| Thermal Shutdown | 170°C activation, 140°C recovery - protects against sustained overload or poor PCB thermal design without latch-off. |
| HS/LS RDS(ON) | 90mΩ / 55mΩ - reduces conduction loss and improves full-load efficiency above 90% at 12V→3.3V conversion. |
Pinout & Package
MP9942AGJ-P is housed in an 8-pin TSOT23-8 package with exposed thermal pad (not electrically connected), optimized for high-power density and thermal performance on 2-layer PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (PG) | Open-drain Power Good output | Pulled low at startup and during fault; rises after VOUT reaches 90% of target with 90μs delay - used for processor reset or system enable sequencing. |
| 2 (IN) | Main input supply rail | Accepts 4–30V; requires local 22μF + 0.1μF ceramic decoupling; wide trace routing essential to minimize voltage drop and noise injection. |
| 3 (SW) | Switch node | Connects to inductor and BST capacitor; high di/dt node - must be routed short/wide and isolated from analog traces like FB. |
| 4 (GND) | System ground reference | Primary return path for power and feedback; requires low-impedance copper pour and multiple vias to inner ground plane. |
| 5 (BST) | Bootstrap supply for high-side driver | Requires 0.1–1μF capacitor between BST and SW; 20Ω series resistor strongly recommended to suppress ringing and improve reliability. |
| 6 (EN/SYNC) | Enable input / external clock sync | Logic-high (>1.4V) enables operation; accepts 200kHz–2.2MHz square wave for frequency synchronization - eliminates beat frequencies in multi-rail systems. |
| 7 (VCC) | Bias supply output | 5V regulated output (±4%); powers internal circuitry; requires 0.1–0.22μF ceramic decoupling placed adjacent to pin. |
| 8 (FB) | Feedback input | Compares output voltage against 792mV reference; connects to resistor divider tap - sensitive node requiring shortest possible trace and guard ring. |
Key Features
| Feature | Design Value |
|---|---|
| Force CCM Mode | Maintains continuous conduction across full load range - eliminates audible noise and ensures predictable loop behavior in industrial control applications. |
| High Duty Cycle Support | Up to 95% maximum duty cycle - sustains regulation during automotive cold-crank events down to 4V input without dropout. |
| Internal Soft-Start | 1.45ms ramp time - prevents inrush current and output overshoot during power-up, eliminating need for external soft-start circuitry. |
| Over-Current Hiccup | Reduces average short-circuit current by periodic restart - limits junction temperature rise and avoids thermal runaway during sustained faults. |
| 410kHz Fixed + Sync Capability | Enables deterministic EMI filtering while allowing synchronization to system clock - critical for noise-sensitive imaging or audio subsystems. |
Applications
| Automotive Infotainment | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering ARM-based application processors and display drivers in head-unit systems subject to 4V–16V battery variation and load-dump transients. IC Role / Device Role / Timing Role: Primary 3.3V/2A buck regulator with PG signaling for SoC reset coordination and cold-crank resilience. Use Value: 36V transient tolerance and 95% max duty cycle ensure uninterrupted operation during engine start; PG output enables safe boot sequencing. |
Use Scenario: Generating isolated 5V rail for digital I/O isolation barriers and fieldbus transceivers in programmable logic controllers. IC Role / Device Role / Timing Role: Compact, thermally robust DC/DC stage converting 24V industrial bus to 5V logic supply with hiccup-mode fault containment. Use Value: Integrated MOSFETs and 1.25W θJA = 100°C/W allow operation at 70°C ambient without heatsink; hiccup mode prevents latch-up during sensor short circuits. |
| Distributed Telecom Power | Medical Sensor Hub |
|
Use Scenario: Local point-of-load conversion from 48V backplane to 3.3V for FPGA configuration and Ethernet PHYs in remote radio units. IC Role / Device Role / Timing Role: Synchronized buck converter operating at 1MHz (via EN/SYNC) to avoid interference with RF front-end clocks. Use Value: External clock sync eliminates beat frequencies; 410kHz base frequency allows optimal inductor selection for 48V→3.3V conversion with minimal core loss. |
Use Scenario: Providing clean, sequenced 1.8V and 3.3V supplies for low-power biosignal acquisition ASICs and Bluetooth LE radios in portable diagnostic devices. IC Role / Device Role / Timing Role: Dual-output power solution (using two MP9942AGJ-P) with PG outputs coordinated to ensure analog front-end powers before digital controller. Use Value: 792mV reference accuracy and low 10nA FB bias current enable precise, low-drift output setting; RoHS/halogen-free compliance meets medical safety standards. |
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 |
|---|---|---|---|
| MP9943AGJ-Z | Same pinout and feature set, but rated for 36V absolute max input (vs. 40V for MP9942AGJ-P) and includes enhanced ESD protection on EN/SYNC. | Preferred for new designs requiring higher robustness against board-level ESD events near enable lines. | Select MP9943AGJ-Z when ESD immunity >2kV HBM on EN/SYNC is required; otherwise MP9942AGJ-P remains optimal for cost-sensitive automotive volume production. |
| TPS54202DRCT | Lower 28V max input, 500kHz default frequency, no PG output, and external compensation - lacks integrated power good and cold-crank support. | Suitable only where PG signaling is unnecessary and input never exceeds 24V; requires additional components for soft-start and fault reporting. | Choose TPS54202DRCT only if TI's ecosystem tools and documentation preference outweigh missing PG, cold-crank, and transient tolerance capabilities. |
Compared with MP9942AGJ-P, MP9943AGJ-Z offers identical functionality with improved EN/SYNC ESD rating, while TPS54202DRCT sacrifices PG, cold-crank, and transient robustness for lower BOM count in non-automotive 24V systems - making MP9942AGJ-P uniquely balanced for automotive and industrial edge nodes.
Availability
MP9942AGJ-P is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and distributed telecom power systems requiring stable component supply, long-term lifecycle assurance, and AEC-Q200-aligned reliability.
Supply support for MP9942AGJ-P 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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.
The MP9942A product line targets high-reliability DC/DC conversion in automotive, industrial, and telecom applications - emphasizing integration, thermal resilience, and functional safety-aware features like PG and hiccup-mode protection.
FAQ
What is the maximum allowable input voltage transient for MP9942AGJ-P?
The MP9942AGJ-P is rated for 36V input transients per datasheet Absolute Maximum Ratings, with continuous operation up to 30V. This 6V margin above nominal 30V operation accommodates ISO 7637-2 Pulse 1 and Pulse 2a load-dump events common in 24V automotive systems without external clamping.
Can MP9942AGJ-P operate in forced continuous conduction mode (FCCM) at light loads?
Yes - MP9942AGJ-P includes Force CCM mode, which maintains switching activity across the full 0–2A load range. This eliminates discontinuous conduction mode (DCM) transitions that cause variable-frequency operation and potential acoustic noise in sensitive applications like medical sensors or audio subsystems.
What is the recommended BST capacitor value and why is a series resistor advised?
A 0.1μF to 1μF ceramic capacitor is recommended between BST and SW pins. A 20Ω resistor in series is strongly advised to dampen high-frequency ringing at the switch node, reducing electromagnetic emissions and preventing false triggering of the bootstrap UVLO, especially under high-duty-cycle conditions.
How does the Power Good (PG) pin behave during thermal shutdown?
During thermal shutdown, the PG pin is actively pulled low regardless of output voltage level. This provides unambiguous fault signaling to host systems - distinguishing thermal events from undervoltage or overvoltage conditions, and enabling immediate system-level thermal mitigation actions.
Is external compensation required for stable operation with standard output capacitors?
No - MP9942AGJ-P uses an optimized internal compensation network compatible with ceramic, tantalum, and electrolytic output capacitors across typical ESR and capacitance ranges. External compensation is not needed unless custom dynamic response or ultra-low-noise requirements demand fine-tuning.
What is the minimum output voltage achievable with MP9942AGJ-P?
The minimum regulated output voltage is 0.8V, set by the internal 792mV feedback reference and resistor divider scaling. Achieving sub-0.8V requires external reference injection or post-regulation, as the error amplifier cannot drive the COMP node below the internal reference threshold.
Does MP9942AGJ-P support output voltages higher than 30V?
No - the maximum output voltage is limited by the 30V continuous input rating and 95% maximum duty cycle. For example, at 30V input, the highest practical output is ~28.5V. Higher outputs require cascaded topologies or alternative controllers with extended duty cycle or transformer isolation.
MP9942AGJ-P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- SOT-23-8 Thin, TSOT-23-8
- 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):
- 30V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28.5V
- Current - Output:
- 2A
- Frequency - Switching:
- 410kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-8
MP9942AGJ-P FAQ
1.How can I place an order for MP9942AGJ-P through Aetrix?
Please submit a Request for Quotation (RFQ) for MP9942AGJ-P 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 MP9942AGJ-P reliable?
The price and inventory of MP9942AGJ-P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP9942AGJ-P is usually 5 days.
3.What payment methods are accepted for MP9942AGJ-P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP9942AGJ-P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP9942AGJ-P?
MP9942AGJ-P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP9942AGJ-P 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 MP9942AGJ-P?
For technical support, including MP9942AGJ-P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP9942AGJ-P requirements.
6.How does Aetrix verify that MP9942AGJ-P is sourced from the original manufacturer or authorized distributors?
All MP9942AGJ-P 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 MP9942AGJ-P meets industry standards.
7.What is the process for return or replacement of MP9942AGJ-P?
All MP9942AGJ-P units undergo pre-shipment inspection (PSI). If there is an issue with MP9942AGJ-P, 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 MP9942AGJ-P part is unused and in its original packaging.
Return procedure for MP9942AGJ-P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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