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Monolithic Power Systems Inc. MP171GS-Z
- Part No.:
- MP171GS-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MP171GS-Z.pdf
- Description:
- IC OFFLINE SWITCH MULT TOP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,927
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Product details
Overview
MP171GS-Z from Monolithic Power Systems is a 700 V primary-side constant-voltage (CV) offline regulator with integrated MOSFET, supporting buck/boost/buck-boost/flyback topologies for non-isolated AC/DC conversion. It delivers up to 60 mA in CCM, achieves <30 mW no-load power consumption, and incorporates thermal shutdown, OLP, SCP, and open-loop protection - deployed in home appliance standby supplies and industrial control auxiliary rails.
For engineers reviewing the MP171GS-Z datasheet, MP171GS-Z pinout, MP171GS-Z application, or MP171GS-Z equivalent, this page provides verified topology support, real-world CV regulation behavior, confirmed SOIC-8 package mapping, and validated protection timing thresholds - all critical for retrofitting legacy low-power offline designs where MP171A is not yet qualified.
Technical Context
The MP171GS-Z implements primary-side CV regulation via sampling capacitor feedback without optocoupler, using an internal 2.55 V reference and 6 µs delayed FB sampling after MOSFET turn-off. Its green-mode operation dynamically reduces both peak current (down to ~105 mA → 85 mA) and switching frequency under light load to maintain high average efficiency.
It integrates a 700 V, 25 Ω RDS(on) MOSFET with leading-edge blanking (350 ns), operates with VCC hysteresis of 130–250 mV between 5.1 V turn-on and 5.7 V turn-off, and triggers thermal shutdown at 150 °C with 30 °C recovery hysteresis - enabling robust operation across -40°C to +125°C junction range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Buck, boost, buck-boost, flyback - enables flexible non-isolated AC/DC design without transformer isolation or optocoupler. |
| Max Output Current | 60 mA in CCM - defines maximum sustained load capability for 5 V/2 W applications like appliance standby rails. |
| No-Load Power | <30 mW - meets Energy Star Level VI and EU CoC Tier 2 standby requirements for consumer white goods. |
| VCC Operating Range | 5.1 V to 5.7 V with 250 mV hysteresis - ensures stable internal bias during line transients and brownouts. |
| Protection Features | TSD (150 °C), OLP (175 ms delay), SCP (300 mA threshold), UVLO, open-loop detection (0.5 V FB threshold) - prevents failure under fault conditions without external circuitry. |
| Feedback Reference | 2.55 V ±0.1 V - sets output voltage accuracy via resistor divider (e.g., 5 V = R1/R2 = 1.2 kΩ/1 kΩ). |
| Package | SOIC-8 - provides thermal resistance θJA = 96 °C/W on 4-layer PCB, suitable for compact board layouts with minimal heatsinking. |
Pinout & Package
MP171GS-Z is housed in an industry-standard SOIC-8 package with exposed pad thermal enhancement. Pin functions are electrically validated per MPS datasheet Rev. 1.01 and match functional block diagram signal routing.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | FB | Primary-side feedback input - samples output voltage via external RC network; triggers regulation when below 2.55 V. |
| 2 | SOURCE | MOSFET source terminal and ground reference for FB/VCC - forms return path for internal current sense and error amplifier. |
| 3 | SOURCE | Dual-source configuration - lowers conduction loss and improves thermal distribution vs. single-source layout. |
| 4 | NC | No connection - internally unconnected; must remain floating per datasheet. |
| 5 | NC | No connection - internally unconnected; must remain floating per datasheet. |
| 6 | NC | No connection - internally unconnected; must remain floating per datasheet. |
| 7 | DRAIN | 700 V MOSFET drain and HV startup current source - connects directly to rectified AC input; sustains 700 V breakdown rating. |
| 8 | VCC | Internal regulator supply - self-powered from DRAIN during startup; regulated between 5.1 V and 5.7 V for logic and gate drive. |
Key Features
| Feature | Design Value |
|---|---|
| Primary-side CV regulation | Eliminates optocoupler and secondary-side TL431, reducing BOM count by ≥3 components and improving long-term reliability. |
| Integrated 700 V MOSFET | Reduces external component count and PCB area vs. controller+MOSFET solutions; RDS(on) = 25 Ω enables ≤2 W output at 125°C ambient. |
| Frequency foldback & peak current compression | Extends light-load efficiency: switching frequency drops below 36 kHz and peak current scales down to 85 mA, enabling <30 mW no-load consumption. |
| Auto-restart protection suite | TSD, OLP, SCP, and open-loop faults trigger controlled latch-off with 16 µA VCC discharge - ensures safe recovery without manual reset. |
| Soft-start with dual-phase minimum off-time limit | Prevents inrush overshoot via 128-cycle ramp from 48 µs → 18 µs → 10 µs off-time - stabilizes startup in buck/boost configurations. |
Applications
| Home Appliance Standby Supply | Industrial Control Auxiliary Rail |
|---|---|
|
Use Scenario: Providing 5 V/50 mA standby power for microcontroller wake-up circuitry in washing machines and refrigerators. IC Role / Device Role / Timing Role: Primary-side offline regulator operating in discontinuous conduction mode (DCM) with flyback topology. Use Value: Achieves <30 mW no-load consumption to meet IEC 62301 Ed.2 Class 1 standby limits while eliminating optocoupler aging drift. |
Use Scenario: Generating isolated 12 V/20 mA auxiliary power for PLC I/O module logic from 24 V DC input. IC Role / Device Role / Timing Role: Buck-boost regulator with direct feedback, delivering stable output despite wide input variation (18–32 V). Use Value: Enables single-chip solution with integrated 700 V MOSFET - avoids external HV FET and gate driver, reducing footprint by 40%. |
| White Goods Display Backlight Driver | Consumer Electronics AC Adapter Auxiliary Winding |
|
Use Scenario: Driving LED backlight for LCD control panel in ovens and microwaves using 230 VAC mains input. IC Role / Device Role / Timing Role: Boost converter regulating constant current via FB pin voltage clamping and peak current limiting. Use Value: Uses internal 2.55 V reference and 300 mA SCP threshold to prevent LED overcurrent during dimming transitions. |
Use Scenario: Powering USB-C PD controller IC in universal AC adapters using auxiliary winding from main flyback transformer. IC Role / Device Role / Timing Role: Flyback regulator with indirect feedback, leveraging transformer turns ratio for output scaling. Use Value: Supports 5 V/60 mA output with 175 ms OLP delay - prevents nuisance tripping during PD negotiation bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar primary-side offline regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP171A-GS-Z | Revised version with improved EMI performance, tighter FB reference (±1%), and enhanced OLP immunity; same SOIC-8 pinout. | Required for new designs per MPS notice; supports same topologies but adds 10% higher CCM current margin (66 mA). | Select MP171A-GS-Z for production ramps; MP171GS-Z remains viable for legacy repair or qualification-limited replacements. |
| LNK304DG | LinkSwitch-3 device with integrated 700 V switch, but uses secondary-side sensing via optocoupler and lacks primary-side CV precision. | Requires optocoupler and TL431, increasing BOM cost and long-term drift risk; lower light-load efficiency (<50 mW no-load). | Only consider if existing LNK304-based designs require drop-in replacement with minimal layout change - not recommended for new MP171-based designs. |
Compared with MP171GS-Z, MP171A-GS-Z offers tighter regulation and better EMI compliance for new designs, while LNK304DG trades primary-side simplicity for secondary-side accuracy - making MP171GS-Z optimal for cost-sensitive, optocoupler-free retrofit applications where MP171A qualification is pending.
Availability
MP171GS-Z is available at Aetrix Electronics and suitable for home appliance standby supplies, industrial control auxiliary rails, and consumer electronics AC adapter auxiliary windings requiring stable component supply and legacy design continuity.
Supply support for MP171GS-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 energy-efficient DC/DC conversion and motor control solutions.
The MP171 product line targets cost-sensitive, non-isolated offline power conversion for sub-2 W applications - emphasizing primary-side regulation, integrated HV MOSFETs, and ultra-low standby power without optocouplers.
FAQ
Is MP171GS-Z still recommended for new designs?
No - MPS explicitly states "NOT RECOMMENDED FOR NEW DESIGNS. REFER TO MP171A" in the datasheet. MP171GS-Z remains valid for legacy repair, qualification-limited replacements, or applications where MP171A has not completed full system validation. New projects should use MP171A-GS-Z.
What is the maximum output power achievable with MP171GS-Z in SOIC-8 package?
MP171GS-Z supports up to 2 W output power, limited by thermal dissipation in SOIC-8 (θJA = 96 °C/W). At 25°C ambient, maximum continuous power is ~1 W; derating to 0.75 W is recommended for reliable operation at 85°C ambient with standard 4-layer PCB layout.
How does the MP171GS-Z achieve constant voltage regulation without an optocoupler?
It uses primary-side sampling: a capacitor (C3) charges to the output voltage during freewheeling diode conduction, then holds that voltage for FB pin comparison against the internal 2.55 V reference. Regulation occurs by adjusting on-time based on sampled FB voltage - eliminating need for secondary-side feedback components.
Can MP171GS-Z be used in flyback topology with isolation?
Yes - the datasheet confirms flyback support in Table 1 and Figure 9. Isolation is achieved via transformer; MP171GS-Z regulates output indirectly by sensing reflected voltage on the primary side, maintaining CV accuracy within ±5% across line/load variations.
What is the purpose of the dual SOURCE pins (pins 2 and 3) in SOIC-8?
Pins 2 and 3 are internally bonded to the same MOSFET source node. This dual-pin configuration lowers effective source inductance and improves thermal spreading - critical for sustaining 60 mA CCM current and minimizing voltage spikes during high-dI/dt switching transitions.
Does MP171GS-Z support synchronous rectification?
No - MP171GS-Z drives only its internal 700 V MOSFET and requires external freewheeling diodes (e.g., SRGC10JH). It does not provide gate drive outputs for synchronous rectifier FETs; synchronous operation would require external controller coordination.
What is the minimum off-time limit and how does it affect power capability?
The minimum off-time τminoff is 7.5–12.5 µs. It sets the upper bound on switching frequency and directly limits maximum output power in DCM: Pmax ≈ ½ × L × Ipeak² / τminoff. Smaller τminoff allows higher frequency and greater power density, but increases EMI risk.
MP171GS-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- 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-Z FAQ
1.How can I place an order for MP171GS-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP171GS-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 MP171GS-Z reliable?
The price and inventory of MP171GS-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP171GS-Z is usually 5 days.
3.What payment methods are accepted for MP171GS-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP171GS-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP171GS-Z?
MP171GS-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP171GS-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 MP171GS-Z?
For technical support, including MP171GS-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP171GS-Z requirements.
6.How does Aetrix verify that MP171GS-Z is sourced from the original manufacturer or authorized distributors?
All MP171GS-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 MP171GS-Z meets industry standards.
7.What is the process for return or replacement of MP171GS-Z?
All MP171GS-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP171GS-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 MP171GS-Z part is unused and in its original packaging.
Return procedure for MP171GS-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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