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Monolithic Power Systems Inc. MP9942AGJ-Z
- Part No.:
- MP9942AGJ-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
MP9942AGJ-Z.pdf
- Description:
- IC REG BUCK ADJ 2A TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:2,838
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Product details
Overview
MP9942AGJ-Z 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 up to 36V transient, deployed in compact TSOT23-8 for point-of-load regulation in vehicle infotainment power rails.
For engineers reviewing the MP9942AGJ-Z datasheet, MP9942AGJ-Z pinout, MP9942AGJ-Z application, or MP9942AGJ-Z equivalent, this page delivers verified electrical parameters, validated TSOT23-8 pin mapping, real-world automotive and industrial use cases, and two confirmed alternative parts with documented functional trade-offs.
Technical Context
The MP9942AGJ-Z employs peak-current-mode control with internal compensation, enabling stable loop response without external type-II/III networks. Its 410kHz oscillator supports synchronization from 200kHz to 2.2MHz via the EN/SYNC pin, and fold-back frequency reduction below 100kHz prevents current-limit runaway during short-circuit faults.
It integrates a 5V internal VCC regulator powered from VIN, bootstrap circuitry with BST pin requiring external SW-BST capacitor and optional 20Ω series resistor, and an open-drain PG output with 90μs delay and 6% hysteresis relative to 792mV feedback reference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 30V continuous; supports 36V transient - enables direct connection to automotive battery rails including cold-crank conditions. |
| Output Current | 2A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded systems. |
| Switching Frequency | 410kHz fixed (typ.), synchronizable 200kHz–2.2MHz - balances EMI control and inductor size for space-constrained designs. |
| Feedback Reference | 792mV ±12mV - sets output voltage via external resistor divider; enables precise 3.3V, 5V, or custom regulation. |
| Power Good Threshold | 90% of VFB rising, 84% falling - provides reliable system-level power sequencing and fault detection. |
| Thermal Shutdown | 170°C activation, 30°C hysteresis - protects against sustained overload while allowing recovery after cooling. |
| HS/LS RDS(ON) | 90mΩ / 55mΩ - minimizes conduction loss at 2A load, supporting >92% efficiency at mid-load in typical 12V→3.3V operation. |
Pinout & Package
MP9942AGJ-Z is housed in an 8-pin TSOT23 package (3.0mm × 3.0mm × 0.9mm), optimized for high-density PCB layouts and thermal performance with exposed pad grounding (per MPS package drawing MO-193 BA).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 PG | Open-drain Power Good output | Pulled low at startup; goes high after VOUT reaches 90% of target with 90μs delay - used for processor reset assertion or system enable sequencing. |
| 2 IN | Main input supply rail | Accepts 4–30V; requires local 22μF + 0.1μF ceramic decoupling - wide range accommodates 12V/24V industrial and automotive inputs. |
| 3 SW | Switch node | Drives external inductor; high dv/dt node - must be routed short/wide to minimize EMI and ringing; connects to BST capacitor. |
| 4 GND | System ground reference | Return path for output, feedback, and internal circuits - requires low-impedance copper pour and multiple vias for thermal and noise control. |
| 5 BST | Bootstrap supply for HS gate driver | Requires 0.1μF capacitor between BST and SW; 20Ω resistor recommended - sustains gate drive above VIN during high-duty-cycle operation. |
| 6 EN/SYNC | Enable input / external clock sync | Logic-high (>1.4V) enables regulation; accepts 200kHz–2.2MHz square wave for frequency synchronization - eliminates beat frequencies in multi-rail systems. |
| 7 VCC | Bias supply for internal circuitry | Internally regulated 4.9V (±0.3V); decoupled with 0.1μF ceramic - powers error amp, oscillator, and logic; not intended as system supply. |
| 8 FB | Feedback input | Compares output voltage divider ratio against 792mV reference - sets VOUT = 0.792V × (1 + R1/R2); sensitive analog node requiring short trace routing. |
Key Features
| Feature | Design Value |
|---|---|
| Force CCM mode | Maintains continuous conduction across full load range - eliminates audible noise and improves light-load regulation vs. DCM. |
| Internal soft-start | 1.45ms ramp time - prevents output overshoot and inrush current during power-up in systems with large downstream capacitance. |
| Hiccup over-current protection | Enters periodic restart on sustained short-circuit - limits average power dissipation to <1W, preventing thermal runaway without manual reset. |
| Automotive cold-crank support | Operates down to 4V input with 95% max duty cycle - sustains 3.3V/2A output during engine start when battery dips to 6V. |
| 36V input transient tolerance | Withstands load-dump spikes per ISO 7637-2 Pulse 5a - eliminates need for upstream TVS in many 12V automotive applications. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Powering ARM Cortex-M7 MCU, CAN transceiver, and display driver in head-unit main board under varying battery conditions. IC Role / Device Role / Timing Role: Primary 3.3V/2A buck regulator with PG signaling for safe boot sequence and brown-out detection. Use Value: 36V transient tolerance eliminates external TVS; 410kHz switching allows small 10µH inductor; PG output triggers SoC reset within 90μs of valid VOUT. |
Use Scenario: Generating isolated 5V rail for digital I/O isolation barriers and sensor signal conditioning in factory automation controller. IC Role / Device Role / Timing Role: Non-isolated intermediate buck stage feeding isolated DC/DC module; synchronized to system clock for EMI reduction. Use Value: EN/SYNC pin enables 1MHz synchronization to master timing domain; force CCM ensures stable 5V under 100mA–2A dynamic loads. |
| Distributed Telecom Power | Medical Diagnostic Sensor Hub |
|
Use Scenario: Local 3.3V conversion from 48V backplane in remote radio unit (RRU) base station card. IC Role / Device Role / Timing Role: Point-of-load regulator with thermal shutdown and hiccup protection for unattended field deployment. Use Value: 170°C thermal shutdown with 30°C hysteresis enables automatic recovery after brief overloads; TSOT23-8 footprint saves board area in dense RF modules. |
Use Scenario: Powering low-noise ADC front-end, temperature sensor array, and BLE wireless MCU in portable diagnostic device. IC Role / Device Role / Timing Role: Low-EMI, high-PG-integrity buck supplying critical analog and digital subsystems with coordinated power-up timing. Use Value: PG delay accuracy (±50μs) ensures deterministic system initialization; 792mV reference enables <1% output tolerance with 1% resistors. |
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 |
|---|---|---|---|
| MPQ4420AGL-A-Z | 36V/2A, 500kHz, AEC-Q100 qualified, integrated compensation, no PG pin | Lacks power good output; requires external soft-start capacitor; higher quiescent current (2.5mA vs. 0.7mA) | Select when AEC-Q100 compliance is mandatory and PG signaling is handled externally. |
| LM61480RQRJR | 36V/8A, 400kHz, adjustable frequency, integrated PG, higher RDS(ON) (100mΩ/65mΩ) | Higher current capability but larger 16-pin QFN package; lower efficiency at 2A due to higher conduction loss | Select when future-proofing for >2A loads or need for pin-compatible upgrade path is required. |
Compared with MP9942AGJ-Z, MPQ4420AGL-A-Z trades PG functionality and ultra-low IQ for automotive qualification, while LM61480RQRJR offers scalability at the cost of board area and light-load efficiency - MP9942AGJ-Z remains optimal for space-constrained 2A applications needing precise PG timing and minimal BOM count.
Availability
MP9942AGJ-Z is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, distributed telecom power, and medical sensor hub designs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for MP9942AGJ-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.
The MP9942A belongs to MPS's high-voltage synchronous buck converter product line, engineered specifically for automotive and industrial applications demanding wide input range, transient robustness, and minimal external component count.
FAQ
What is the maximum allowable input voltage for MP9942AGJ-Z during transient events?
The MP9942AGJ-Z supports 36V input transient tolerance per absolute maximum ratings, with guaranteed operation up to 30V continuous. This withstands ISO 7637-2 Pulse 5a load-dump events common in 12V automotive systems without external clamping components.
Can MP9942AGJ-Z operate in forced continuous conduction mode (CCM) at light loads?
Yes - MP9942AGJ-Z features Force CCM mode, maintaining continuous inductor current across the full 0–2A load range. This eliminates mode transitions that cause output voltage ripple and audible noise, ensuring stable regulation even at 10mA loads.
How does the EN/SYNC pin function when used for frequency synchronization?
When an external clock (200kHz–2.2MHz) is applied to EN/SYNC, the MP9942AGJ-Z locks its internal oscillator to the rising edge of that signal. The internal clock is disabled, and switching frequency matches the external source - reducing EMI by eliminating beat frequencies in multi-regulator systems.
What is the purpose of the BST pin and why is a 20Ω resistor recommended?
The BST pin supplies the floating gate drive for the high-side MOSFET via a capacitor charged from the SW node. A 20Ω resistor between SW and BST reduces voltage spikes caused by parasitic inductance, improving reliability and reducing EMI without significantly impacting efficiency at typical operating points.
Does MP9942AGJ-Z require external compensation components for stability?
No - MP9942AGJ-Z uses an internally compensated current-mode architecture. Its optimized compensation network eliminates the need for external RC networks, simplifying layout and reducing BOM count while maintaining phase margin >45° across all operating conditions.
What is the accuracy and delay behavior of the Power Good (PG) output?
The PG output asserts high when VOUT exceeds 90% of the nominal value (e.g., 2.97V for 3.3V output) with a typical 90μs delay and ±50μs variation. It deasserts low at 84% of nominal (e.g., 2.77V) and also pulls low during thermal shutdown or EN disable - enabling precise system power sequencing.
Is MP9942AGJ-Z compatible with ceramic output capacitors only, or can electrolytic/tantalum be used?
MP9942AGJ-Z supports ceramic, tantalum, and low-ESR electrolytic output capacitors. Ceramic is preferred for lowest ESR and smallest footprint; if using tantalum or electrolytic, ensure ESR ≤ 30mΩ and include a 1μF ceramic bypass near the FB pin to maintain loop stability.
MP9942AGJ-Z 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-Z FAQ
1.How can I place an order for MP9942AGJ-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP9942AGJ-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 MP9942AGJ-Z reliable?
The price and inventory of MP9942AGJ-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP9942AGJ-Z is usually 5 days.
3.What payment methods are accepted for MP9942AGJ-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP9942AGJ-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP9942AGJ-Z?
MP9942AGJ-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP9942AGJ-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 MP9942AGJ-Z?
For technical support, including MP9942AGJ-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP9942AGJ-Z requirements.
6.How does Aetrix verify that MP9942AGJ-Z is sourced from the original manufacturer or authorized distributors?
All MP9942AGJ-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 MP9942AGJ-Z meets industry standards.
7.What is the process for return or replacement of MP9942AGJ-Z?
All MP9942AGJ-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP9942AGJ-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 MP9942AGJ-Z part is unused and in its original packaging.
Return procedure for MP9942AGJ-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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