Monolithic Power Systems Inc. MP150GS

Overview

MP150GS from Monolithic Power Systems is a primary-side constant voltage (CV) regulator IC with integrated 500V/30Ω MOSFET, supporting Buck, Buck-boost, Boost, and Flyback topologies for offline AC/DC conversion. It delivers up to 2W output power, achieves <150mW no-load consumption, and operates across -40°C to +125°C junction temperature in SOIC8 package - ideal for low-power standby and home appliance power supplies.

For engineers reviewing the MP150GS datasheet, MP150GS pinout, MP150GS application, or MP150GS equivalent, this page provides verified technical context, real-world design meaning of key specs, validated SOIC8 pin functions, topology-specific use cases, and two confirmed alternative regulators with documented functional trade-offs.

Technical Context

The MP150GS implements green-mode operation via simultaneous frequency foldback and peak current compression: switching frequency drops below 37kHz and peak current limit decreases from 290mA as load diminishes, enabling <150mW no-load power draw. Its internal high-voltage current source powers the IC directly from the Drain pin, eliminating external start-up circuitry.

It uses primary-side regulation with sample-and-hold feedback via the FB pin, referencing 2.55V typical VFB threshold, and enforces a 18μs minimum OFF time (with soft-start ramping from 72μs to 18μs over 384 cycles). Protection includes thermal shutdown at 150°C, OLP triggered after 170ms at 37kHz when VFB falls below 1.7V, and SCP activation at 450mA peak current.

Key Specifications

Pinout & Package

MP150GS is housed in an 8-pin SOIC package with exposed pad connected to Drain for thermal enhancement. Pin 1 is VCC; pins 3 and 4 are SOURCE (common ground reference); pin 7 is DRAIN (HV MOSFET drain and start-up current source); pin 2 is FB (feedback input); pins 5, 6, and 8 are not connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side offline regulator applications.

Compared with MP157GS, MP150GS offers lower cost and sufficient ruggedness for 265VAC-limited appliances; versus LNK3206G, it provides greater design adaptability across topologies and precise FB-based output adjustment - critical for multi-rail industrial systems requiring tight cross-regulation.

Availability

MP150GS is available at Aetrix Electronics and suitable for home appliance auxiliary power, smart sensor standby supplies, and industrial control panel interfaces requiring stable component supply across multi-year production cycles.

Supply support for MP150GS 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 MP150 product line targets cost-sensitive, low-power offline AC/DC conversion in consumer and industrial applications, emphasizing integration, efficiency at light load, and simplified compliance with global energy standards.

FAQ

What topologies does MP150GS support, and which require isolation?

MP150GS supports Buck, Buck-boost, Boost, and Flyback topologies. Only Flyback provides galvanic isolation via transformer coupling; the other three are non-isolated and produce output referenced to input ground. Flyback is required for safety-critical applications like medical or industrial control panels where user-accessible outputs must be isolated from mains.

How does MP150GS achieve primary-side regulation without an optocoupler?

MP150GS samples the output voltage indirectly using a capacitor coupled to the secondary winding during the MOSFET OFF period. This "sample-and-hold" technique captures the reflected output voltage, allowing the FB pin to regulate based on that sampled value - eliminating the need for optocoupler feedback and secondary-side error amplifier.

What is the maximum recommended output current for MP150GS in CCM and DCM modes?

In continuous conduction mode (CCM), MP150GS supports maximum output current less than 200mA; in discontinuous conduction mode (DCM), it supports less than 120mA. These limits derive from peak current limit (290mA typ) and minimum OFF time (18μs), and are validated in typical 5V/200mA Flyback designs per datasheet Figure 11.

Can MP150GS operate directly from 230VAC rectified input without additional pre-regulation?

Yes - MP150GS integrates a 500V MOSFET and internal HV start-up current source, enabling direct connection to the rectified DC bus from 85–265VAC inputs. No external pre-regulator or Zener clamp is needed, provided the input capacitor is sized per surge requirements (e.g., 10μF for 1kV surge per Table 2).

What thermal considerations apply to MP150GS in SOIC8 package?

MP150GS has θ_JA = 96°C/W on a standard 4-layer PCB. With 1W max power dissipation at 25°C ambient, junction temperature rises ~96°C - approaching the 150°C thermal shutdown threshold. Use thermal relief pads connected to large copper areas, especially under the exposed Drain pad, and avoid exceeding 2W output in sustained operation without airflow or heatsinking.

How does the OLP protection timer behave at switching frequencies other than 37kHz?

The OLP delay time scales inversely with switching frequency: τ_OLP ≈ 170ms × (37kHz / f_s). For example, at 50kHz, OLP triggers after ~126ms; at 25kHz, after ~252ms. This ensures consistent energy-based overload detection regardless of operating frequency set by inductor value and input voltage.

Is MP150GS RoHS-compliant and halogen-free?

Yes - MP150GS is lead-free, halogen-free, and fully compliant with the EU RoHS Directive 2011/65/EU. All MPS products adhere to strict environmental standards, and full compliance documentation is available on the Monolithic Power Systems Quality Assurance webpage.