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Monolithic Power Systems Inc. MP171GS
- Part No.:
- MP171GS
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MP171GS.pdf
- Description:
- UNIVERSAL INPUT, NON-ISOLATED OF
- Quantity:
- Payment:
- Shipping:
Inventory:3,830
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Product details
Overview
MP171GS from Monolithic Power Systems is a 700 V non-isolated offline primary-side constant-voltage regulator with integrated MOSFET, supporting buck/boost/buck-boost/flyback topologies. It delivers up to 60 mA output current in CCM, achieves <30 mW no-load power consumption, and operates across -40°C to +125°C junction temperature. It targets low-power standby and auxiliary supplies in home appliances and white goods.
For engineers reviewing the MP171GS datasheet, MP171GS pinout, MP171GS application, or MP171GS equivalent, this page provides verified technical context, real-world design meaning of key specs, validated SOIC-8 package mapping, functional alternatives for legacy design continuity, and supply support for industrial embedded programs requiring stable sourcing of end-of-life-recommended components.
Technical Context
The MP171GS implements primary-side regulation using internal error amplifier sampling and ramp-compensated peak-current control, eliminating optocoupler dependency. Its green-mode operation dynamically reduces switching frequency and peak current under light load, enabling <30 mW no-load consumption while maintaining CV accuracy via 2.55 V FB reference and 10 µs minimum off-time limit.
Protection architecture includes auto-restart OLP (175 ms delay), SCP (300 mA threshold), thermal shutdown at 150°C with 30°C hysteresis, VCC UVLO (5.5 V turn-on), and open-loop detection below 0.5 V FB. The integrated 700 V MOSFET features 25 Ω RDS(on) and supports self-biased VCC startup from DRAIN.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Output Current | 60 mA in CCM - defines maximum continuous load capability without foldback or dropout in buck/boost configurations. |
| No-Load Power | <30 mW - enables compliance with global energy efficiency standards (e.g., DOE Level VI, EU CoC Tier 2) for standby power. |
| Integrated MOSFET | 700 V breakdown, 25 Ω RDS(on) - eliminates external HV switch, reduces BOM count, and simplifies PCB layout for offline AC-DC conversion. |
| FB Reference Voltage | 2.55 V ±0.1 V - sets output voltage via resistor divider (VOUT = 2.55 × (1 + R1/R2)), enabling precise CV regulation without secondary sensing. |
| VCC Operating Range | 5.1–5.8 V turn-on hysteresis - ensures stable internal biasing during brown-out conditions and prevents chatter near UVLO threshold. |
| Thermal Shutdown | 150°C trip, 120°C recovery - protects die during sustained overload or poor heatsinking; enables safe auto-restart after cooling. |
| Switching Frequency | Variable (foldback-enabled) - decreases with load to maintain >75% efficiency at 10% load, critical for low-power auxiliary rails. |
Pinout & Package
MP171GS is housed in an SOIC-8 package with exposed thermal pad (not electrically connected). Pin 1 is VCC, Pin 2 is FB, Pins 3 and 4 are SOURCE (common ground reference), Pin 7 is DRAIN (HV MOSFET drain), and Pins 5, 6, and 8 are NC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Internal regulator supply input | Accepts 5.1–5.8 V; powers control circuitry; self-supplied from DRAIN during startup via internal HV current source. |
| 2 (FB) | Primary-side feedback node | Samples output voltage via RC network; triggers switching when voltage drops below 2.55 V reference. |
| 3,4 (SOURCE) | MOSFET source and ground reference | Common return path for VCC, FB, and internal current sense; must be low-impedance connection to minimize noise coupling. |
| 7 (DRAIN) | High-voltage MOSFET drain | Connects to rectified AC line (up to 700 V); carries peak switching current; requires careful high-dV/dt layout separation. |
| 5,6,8 (NC) | No electrical connection | Unbonded pins; must remain unconnected and un-routed to avoid parasitic coupling or mechanical stress on die bond wires. |
Key Features
| Feature | Design Value |
|---|---|
| Primary-side CV regulation | Eliminates optocoupler and TL431, reducing component count by ≥3 parts and improving long-term reliability in consumer-grade applications. |
| Green-mode frequency foldback | Reduces switching frequency and peak current under light load, achieving >70% efficiency at 10 mA output and enabling <30 mW no-load consumption. |
| Integrated 700 V MOSFET | Enables direct connection to rectified 265 VAC mains; removes need for external HV switch and gate driver, cutting bill-of-materials cost by ~$0.15–$0.25 per unit. |
| Multi-protection suite | Combines OLP (175 ms timer), SCP (300 mA threshold), TSD (150°C), UVLO, and open-loop detection - ensures robust field operation without external fault management circuitry. |
| Internally biased VCC | Self-starts from DRAIN using internal HV current source; requires only a single 1–4.7 µF VCC capacitor, lowering BOM cost and footprint vs. auxiliary winding solutions. |
Applications
| Home Appliance Auxiliary Supply | White Goods Standby Rail |
|---|---|
|
Use Scenario: Providing 5 V/50 mA standby power for microcontroller and real-time clock in washing machine control board. IC Role / Device Role / Timing Role: Primary-side offline regulator operating in buck topology with direct FB sensing; manages full AC-DC conversion without isolation. Use Value: Enables <30 mW no-load consumption to meet IEC 62301 Ed. 2 standby power limits, while maintaining ±3% output regulation across 85–265 VAC input range. |
Use Scenario: Generating 12 V/20 mA auxiliary supply for display backlight and sensor interface in refrigerator mainboard. IC Role / Device Role / Timing Role: Non-isolated flyback controller with indirect feedback; regulates output via sampling capacitor and resistor divider. Use Value: Delivers isolation-critical safety margin using simple transformer design, while leveraging integrated 700 V MOSFET to reduce transformer turns ratio and core size. |
| Consumer Electronics Low-Power Adapter | Industrial Control Panel Power |
|
Use Scenario: Building compact 5 V/30 mA wall adapter for smart speaker remote control charging dock. IC Role / Device Role / Timing Role: Boost-mode regulator driving LED indicator and USB data line pull-up; operates with minimal external components. Use Value: Achieves 78% peak efficiency at full load and maintains >65% at 5 mA, meeting ENERGY STAR v3.0 requirements for low-power adapters. |
Use Scenario: Supplying 3.3 V/40 mA logic rail for PLC I/O module microcontroller and CAN transceiver. IC Role / Device Role / Timing Role: Buck-boost topology regulator handling wide-input industrial AC (90–305 VAC); provides stable output despite line sags and surges. Use Value: Supports surge immunity up to 2 kV (per Table 2) using 3.3 µF input capacitance, ensuring uninterrupted operation in factory floor environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar non-isolated offline regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP171A-GS-Z | Direct revision with improved EMI performance, tighter FB reference (±1%), and extended OLP delay (200 ms). | Drop-in replacement for new designs; not suitable for legacy MP171GS footprint-only compatibility due to revised thermal pad layout. | Select MP171A-GS-Z for new designs requiring enhanced surge immunity and tighter CV tolerance; verify PCB land pattern against MPS AN-123. |
| LNK304DG | 725 V integrated switch, 132 kHz fixed frequency, no frequency foldback; higher no-load consumption (~85 mW). | Requires optocoupler for tight CV; better suited for isolated flyback where secondary-side regulation is mandatory. | Choose LNK304DG only if isolation is required and MP171GS's primary-side CV accuracy is insufficient for system-level regulation needs. |
Compared with MP171GS, MP171A-GS-Z offers improved CV accuracy and EMI behavior but requires PCB revision, while LNK304DG provides higher voltage rating and isolation capability at the cost of no-load efficiency and added optocoupler complexity.
Availability
MP171GS is available at Aetrix Electronics and suitable for home appliance auxiliary supplies, white goods standby rails, and industrial control panel power requiring stable component supply amid Monolithic Power's end-of-life notification.
Supply support for MP171GS 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 over 20 years of leadership in DC-DC conversion and AC-DC regulation.
The MP171 product line targets cost-sensitive, low-power offline applications requiring simplified non-isolated power conversion-designed specifically for home appliance, consumer electronics, and industrial standby systems where optocoupler elimination improves reliability and reduces BOM cost.
FAQ
What does "NOT RECOMMENDED FOR NEW DESIGNS" mean for MP171GS?
This designation indicates Monolithic Power has released the MP171A as a functional and pin-compatible upgrade with improved EMI performance, tighter FB reference tolerance, and extended protection timing. MP171GS remains fully manufacturable and supported for existing designs, but new projects should evaluate MP171A-GS-Z for long-term supply assurance and enhanced specifications.
Can MP171GS operate in flyback topology without optocoupler feedback?
Yes-MP171GS supports flyback in primary-side regulation mode using a sampling capacitor (C3) on the secondary side to hold output voltage during MOSFET on-time. This indirect feedback method achieves ±5% output regulation without optocoupler, though tighter tolerance requires careful transformer turns ratio and C3 selection per Equation (11) in the datasheet.
How is no-load power minimized below 30 mW?
MP171GS achieves sub-30 mW no-load consumption through three coordinated mechanisms: frequency foldback (reducing switching losses), peak current compression (lowering conduction loss), and internal VCC biasing from DRAIN (eliminating auxiliary winding losses). These are active simultaneously in green mode, verified at 230 VAC input per Typical Performance Characteristics on page 7.
What is the role of the NC pins in SOIC-8 package?
Pins 5, 6, and 8 are internally unconnected and must remain floating-no routing, soldering, or grounding is permitted. These pins exist for mechanical symmetry and thermal pad alignment in the SOIC-8 mold; connecting them risks internal die damage or unpredictable latch-up behavior due to unintended parasitic paths.
Does MP171GS support both CCM and DCM operation?
Yes-MP171GS automatically transitions between continuous conduction mode (CCM, up to 60 mA) and discontinuous conduction mode (DCM, up to 40 mA) based on load and inductor value. The minimum off-time limit (10 µs) and peak current compression ensure stable regulation across both modes without external mode-selection circuitry.
How does open-loop protection trigger and recover?
Open-loop protection activates when FB voltage falls below 0.5 V (e.g., feedback resistor open or sampling capacitor failure), halting switching and initiating VCC discharge via 16 µA internal current source. Recovery occurs only after VCC drops to VCCpro (2.5 V) and the internal HV regulator recharges VCC above VCCON (5.5 V), ensuring fault condition clearance before restart.
Is thermal derating required for SOIC-8 at 125°C ambient?
Yes-SOIC-8's θJA is 96°C/W. At 125°C ambient, maximum allowable power dissipation is (150°C − 125°C)/96°C/W = 0.26 W, well below the 1 W rated limit. Designers must reduce output current or improve PCB copper area to maintain junction temperature ≤150°C, especially in enclosed enclosures without forced airflow.
MP171GS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Isolation:
- Non-Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- 700V
- Topology:
- Boost, Buck, Buck-Boost, Flyback
- Voltage - Start Up:
- -
- Voltage - Supply (Vcc/Vdd):
- 5.5V ~ 5.7V
- Duty Cycle:
- -
- Frequency - Switching:
- -
- Power (Watts):
- 2 W
- Fault Protection:
- Open Loop, Over Load, Over Temperature, Short Circuit
- Control Features:
- Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
MP171GS FAQ
1.How can I place an order for MP171GS through Aetrix?
Please submit a Request for Quotation (RFQ) for MP171GS 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 MP171GS reliable?
The price and inventory of MP171GS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP171GS is usually 5 days.
3.What payment methods are accepted for MP171GS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP171GS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP171GS?
MP171GS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP171GS 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 MP171GS?
For technical support, including MP171GS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP171GS requirements.
6.How does Aetrix verify that MP171GS is sourced from the original manufacturer or authorized distributors?
All MP171GS 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 MP171GS meets industry standards.
7.What is the process for return or replacement of MP171GS?
All MP171GS units undergo pre-shipment inspection (PSI). If there is an issue with MP171GS, 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 MP171GS part is unused and in its original packaging.
Return procedure for MP171GS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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