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Monolithic Power Systems Inc. MP155GS-Z
- Part No.:
- MP155GS-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MP155GS-Z.pdf
- Description:
- IC OFFLINE SWITCH MULT TOP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,292
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Product details
Overview
MP155GS-Z from Monolithic Power Systems is a primary-side, green-mode off-line regulator IC with integrated 500V/20Ω MOSFET, supporting Buck, Buck-boost, Boost, and Flyback topologies. It delivers up to 4W output power, achieves <100mW no-load consumption, and provides constant voltage regulation without opto-coupler. Used in home appliance standby supplies and low-power AC/DC converters.
For engineers reviewing the MP155GS-Z datasheet, MP155GS-Z pinout, MP155GS-Z application, or MP155GS-Z equivalent, this page details its primary-side CV control architecture, thermal shutdown with auto-restart, VCC UVLO hysteresis (5.1–5.6V), frequency foldback behavior, and DCM/CCM current limits (130mA/220mA) for accurate low-power design validation.
Technical Context
The MP155GS-Z implements primary-side constant voltage regulation via feedback sampling from an auxiliary winding or output capacitor, eliminating opto-coupler dependency. Its internal 500V MOSFET enables direct high-voltage drain connection, while the FB pin monitors regulated output through a resistor divider referenced to 2.55V typical threshold.
Green-mode operation dynamically scales peak current (290mA typ → down to ~260mA) and switching frequency under light load, enabled by minimum OFF-time control (18μs normal, soft-started from 72μs) and leading-edge blanking (350ns). Protection logic includes timer-based OLP (170ms delay at 37kHz), SCP at 450mA, and open-loop detection at 60mV FB voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Buck, Buck-boost, Boost, Flyback - enables flexible non-isolated and isolated low-power AC/DC designs without external HV FET. |
| Integrated MOSFET | 500V breakdown, 20Ω RDS(on) - eliminates external HV switch, reduces BOM count and layout complexity. |
| No-load Power | <100mW - meets Energy Star and EU CoC Tier 2 standby efficiency requirements for white goods. |
| Output Power | Up to 4W - suitable for auxiliary rails in appliances, smart sensors, and IoT edge devices. |
| FB Reference Voltage | 2.55V ±0.1V - sets precise output via R1/R2 divider; enables 5V, 12V, 16V, or 24V outputs with standard resistors. |
| VCC UVLO Threshold | 5.3V turn-on / 5.6V turn-off with 250mV hysteresis - ensures stable startup and prevents brown-out oscillation. |
| Thermal Shutdown | 150°C with auto-restart - protects against sustained overload or poor heatsinking in enclosed environments. |
Pinout & Package
MP155GS-Z is supplied in SOIC-8 package with exposed pad connected to Drain for thermal enhancement. Pin 1 is VCC, Pin 2 is FB, Pins 3–4 are SOURCE (internally tied), Pin 7 is DRAIN, and Pins 5, 6, 8 are NC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Internal bias supply input | Receives regulated 5.3–5.6V from external capacitor; powers control circuitry and enables UVLO hysteresis. |
| FB (Pin 2) | Feedback sensing node | Monitors output via resistor divider; triggers switching when voltage drops below 2.55V reference. |
| SOURCE (Pins 3,4) | MOSFET source and ground reference | Common return for VCC and FB; must be low-impedance connection to minimize noise coupling. |
| DRAIN (Pin 7) | High-voltage MOSFET drain | Connects directly to rectified AC line (up to 500V); carries full switching current and requires careful layout. |
Key Features
| Feature | Design Value |
|---|---|
| Primary-side CV control | Eliminates opto-coupler and secondary-side TL431, reducing cost, size, and component count in low-power SMPS. |
| Frequency foldback + peak current compression | Reduces switching losses and conduction losses simultaneously at light load, enabling <100mW no-load consumption. |
| Internal 350ns leading-edge blanking | Suppresses false current-sense triggering from parasitic ringing during MOSFET turn-on, improving reliability. |
| Timer-based overload protection | 170ms fault timeout at 37kHz prevents nuisance tripping during transient overloads while ensuring safety compliance. |
| Auto-restart thermal shutdown | Shuts down at 150°C junction temperature and resumes after VCC discharge/recharge cycle, avoiding latch-off failure mode. |
Applications
| Smart Home Appliance Control | Industrial Sensor Node Power |
|---|---|
Use Scenario: Standby power supply for washing machine MCU, display, and Wi-Fi module during off-cycle. IC Role / Device Role / Timing Role: Primary-side CV regulator providing 5V/100mA isolated auxiliary rail from 230VAC mains. Use Value: Achieves <100mW no-load draw to meet IEC 62301 Ed.2 Class I standby limits while maintaining ±3% output regulation across line/load. | Use Scenario: Compact 12V/200mA power stage for battery-less industrial temperature sensor with wired Ethernet interface. IC Role / Device Role / Timing Role: Flyback topology regulator delivering isolated 12V output with primary-side sensing and auto-restart OLP. Use Value: Enables single-chip solution with integrated 500V MOSFET-no external HV switch required-reducing bill-of-materials by 3 components. |
| White Goods Auxiliary Supply | IoT Edge Device Adapter |
Use Scenario: Low-cost 3.3V/50mA auxiliary supply for refrigerator control board, replacing linear transformer-based design. IC Role / Device Role / Timing Role: Buck-boost topology regulator operating from universal 85–265VAC input with direct feedback. Use Value: Delivers >75% efficiency at 10% load via frequency foldback, improving average efficiency over legacy solutions. | Use Scenario: Wall adapter core for smart plug with embedded energy metering and BLE radio. IC Role / Device Role / Timing Role: Boost topology regulator generating 5V from rectified 120VAC, supporting USB-PD negotiation on secondary side. Use Value: Integrated 500V MOSFET and 2.55V FB reference enable compact PCB layout with minimal external components-no opto-coupler or secondary controller needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar primary-side off-line regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP157GS-Z | Higher 650V MOSFET, 350mA peak current limit, supports up to 6W output | Better suited for higher-input surge environments (e.g., industrial 300VAC lines) and 5–6W loads | Select when input surge immunity >2kV or output power >4W is required; pin-compatible but higher VBR increases cost |
| LNK304DG | Secondary-side feedback via opto-coupler, 700V MOSFET, no frequency foldback | Requires opto-coupler and TL431; higher no-load consumption (~150mW) | Choose only if existing design uses secondary regulation or requires tighter CV accuracy (<±2%) at full load |
Compared with MP157GS-Z, MP155GS-Z offers lower system cost and smaller footprint for ≤4W applications, while LNK304DG trades primary-side simplicity for tighter regulation at the expense of BOM count and standby loss.
Availability
MP155GS-Z is available at Aetrix Electronics and suitable for home appliance standby power, industrial sensor node supplies, and IoT edge device adapters requiring stable component supply across multi-year production cycles.
Supply support for MP155GS-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, headquartered in Kirkland, WA, with global design and support centers.
The MP155 belongs to MPS's primary-side regulation product line, designed specifically for cost-sensitive, low-power AC/DC conversion in consumer and industrial applications where opto-coupler elimination and ultra-low standby loss are critical.
FAQ
What topologies does MP155GS-Z support, and which require isolation?
MP155GS-Z supports Buck, Buck-boost, Boost, and Flyback topologies. Only Flyback provides galvanic isolation via transformer coupling; the other three are non-isolated and deliver referenced output. Flyback is selected when safety isolation (e.g., UL/IEC creepage) or multiple output rails are required.
How does MP155GS-Z achieve <100mW no-load consumption?
It combines green-mode operation-reducing both switching frequency and peak current under light load-with internal 350ns leading-edge blanking, low VCC operating current (250μA), and auto-shutdown of the internal HV current source when VCC exceeds 5.6V. These features collectively suppress idle losses without external circuitry.
What is the function of the SOURCE pins (3 and 4) in SOIC-8 package?
Pins 3 and 4 are internally bonded together as the MOSFET source terminal and serve as the common ground reference for VCC and FB circuits. They must be connected to a low-impedance ground plane-never split-to prevent noise injection into feedback and ensure stable regulation.
Can MP155GS-Z be used in a Buck configuration with 230VAC input?
No-Buck topology requires input voltage always greater than output voltage. With 230VAC rectified to ~325VDC, a 5V or 12V Buck would demand impractical duty cycles and violate minimum OFF-time constraints. Buck-boost or Flyback are appropriate for high-input/low-output conversion.
What is the significance of the 170ms OLP timer delay?
The 170ms timer prevents false triggering during startup or brief load surges. It begins only when FB voltage remains below 1.7V for the full duration at nominal 37kHz switching frequency-ensuring the regulator distinguishes sustained overload from transient events per IEC/UL safety standards.
How is VCC supplied in MP155GS-Z, and why is it critical?
VCC is charged via an internal HV current source from the DRAIN pin during startup, then maintained by an external capacitor charged from the output via a diode/resistor network. Proper VCC sizing (several µF) stabilizes bias supply, prevents UVLO oscillation, and ensures reliable OLP/SCP response-undersized VCC causes erratic shutdowns.
Does MP155GS-Z require an external current-sense resistor?
No-MP155GS-Z uses internal current sensing via the MOSFET's RDS(on). The peak current limit (290mA typ) and SCP threshold (450mA) are set internally, eliminating external sense resistors and associated power loss and layout sensitivity.
MP155GS-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:
- Active
- Output Isolation:
- Non-Isolated
- Internal Switch(s):
- Yes
- Voltage - Breakdown:
- 500V
- Topology:
- Boost, Buck, Buck-Boost, Flyback
- Voltage - Start Up:
- -
- Voltage - Supply (Vcc/Vdd):
- 5.3V ~ 5.6V
- Duty Cycle:
- -
- Frequency - Switching:
- -
- Power (Watts):
- 4 W
- Fault Protection:
- Open Loop, Over Load, Over Temperature, Short Circuit
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
MP155GS-Z FAQ
1.How can I place an order for MP155GS-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP155GS-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 MP155GS-Z reliable?
The price and inventory of MP155GS-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP155GS-Z is usually 5 days.
3.What payment methods are accepted for MP155GS-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP155GS-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP155GS-Z?
MP155GS-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP155GS-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 MP155GS-Z?
For technical support, including MP155GS-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP155GS-Z requirements.
6.How does Aetrix verify that MP155GS-Z is sourced from the original manufacturer or authorized distributors?
All MP155GS-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 MP155GS-Z meets industry standards.
7.What is the process for return or replacement of MP155GS-Z?
All MP155GS-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP155GS-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 MP155GS-Z part is unused and in its original packaging.
Return procedure for MP155GS-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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