Monolithic Power Systems Inc. MP150GJ-Z

Overview

MP150GJ-Z 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. It delivers up to 2W output power, achieves <150mW no-load consumption, and operates in green-mode with frequency foldback and peak current compression for high light-load efficiency. It is used in offline low-power AC/DC converters for home appliances and standby power supplies.

For engineers reviewing the MP150GJ-Z datasheet, MP150GJ-Z pinout, MP150GJ-Z application, or MP150GJ-Z equivalent, key selection criteria include its primary-side regulation architecture, integrated high-voltage MOSFET, VCC UVLO thresholds (5.3V turn-on / 5.6V turn-off), FB reference voltage (2.55V typ), and thermal shutdown at 150°C - all critical for isolated/non-isolated SMPS design validation.

Technical Context

The MP150GJ-Z implements primary-side regulation via sampling capacitor feedback, eliminating optocouplers and secondary-side references. Its internal error amplifier samples FB 6µs after MOSFET turn-off and applies ramp compensation that scales exponentially with decreasing load, enabling precise CV control across 0–200mA CCM output range.

It uses a dual-stage minimum OFF time limit (72µs → 36µs → 18µs soft-start) and leading-edge blanking (350ns for current sense, 180ns for SCP). Protection logic includes auto-restart OLP (170ms delay at 37kHz), SCP (450mA threshold), open-loop detection (60mV FB threshold), and thermal shutdown with VCC discharge to 2.4V.

Key Specifications

Pinout & Package

MP150GJ-Z is packaged in TSOT23-5, a thermally enhanced 5-pin surface-mount package with exposed drain pad for improved heat dissipation. Pin 1 is VCC, Pin 2 is FB, Pins 3 & 4 are SOURCE (internally tied), and Pin 5 is DRAIN. No pins are NC in this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP150GJ-Z, MP157GJ-Z extends voltage rating and power capability while maintaining pinout compatibility, whereas LNK304DG trades integration for greater layout flexibility and EMI tuning - making MP150GJ-Z optimal for cost-sensitive, space-constrained ≤2W applications needing minimal external components.

Availability

MP150GJ-Z is available at Aetrix Electronics and suitable for home appliance control boards, IoT sensor hubs, and industrial standby power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP150GJ-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 core expertise in DC/DC conversion, LED drivers, and motor control solutions.

The MP150 product line targets cost-sensitive, low-power offline AC/DC conversion, emphasizing primary-side regulation, integrated high-voltage MOSFETs, and green-mode efficiency for consumer and industrial auxiliary power applications.

FAQ

What topologies does MP150GJ-Z support, and which require isolation?

MP150GJ-Z supports Buck, Buck-boost, Boost, and Flyback topologies. Only Flyback provides galvanic isolation; the others are non-isolated. Isolation is determined by transformer usage-not the IC itself-so Flyback designs use a transformer for safety separation, while Buck/Buck-boost/Boost rely on input filtering and creepage/clearance compliance.

How does MP150GJ-Z achieve constant voltage regulation without an optocoupler?

MP150GJ-Z uses primary-side regulation via a sampling capacitor (C3 in typical schematics) that captures output voltage during freewheeling phase. The FB pin monitors this sampled voltage, and internal error amplifier compares it to 2.55V reference. This eliminates need for optocoupler and secondary-side feedback components.

What is the maximum continuous output power achievable with MP150GJ-Z in CCM mode?

In continuous conduction mode (CCM), MP150GJ-Z delivers up to 2W output power at 5V/200mA with proper inductor selection (e.g., 1mH) and 230VAC input. This is constrained by 290mA peak current limit and 18µs minimum off-time; exceeding these causes transition to DCM or OLP activation.

Does MP150GJ-Z require an external startup resistor, and how is VCC powered?

No external startup resistor is required. MP150GJ-Z integrates a high-voltage current source connected to the DRAIN pin that charges the VCC capacitor during start-up. Once VCC reaches 5.6V, the internal regulator turns off and the IC switches; VCC is then sustained by auxiliary winding or capacitive dropper.

What protection features are implemented, and do they auto-recover?

MP150GJ-Z includes thermal shutdown (150°C), short-circuit protection (450mA), over-load protection (170ms timer), open-loop detection (60mV FB), and VCC UVLO. All protections trigger auto-restart: after fault removal, internal 16µA current source recharges VCC from 2.4V to 5.3V, restarting normal operation.

Can MP150GJ-Z be used in designs requiring <30mW no-load consumption?

No. MP150GJ-Z specifies <150mW no-load consumption - sufficient for Level VI and CoC Tier 2 - but not for stricter <30mW requirements (e.g., some EU ERP Lot 9 mandates). For sub-30mW, consider MPS's MP174GQ or competing ICs with deeper burst-mode depth and lower quiescent current.

Is the TSOT23-5 package of MP150GJ-Z thermally adequate for 2W operation?

Yes, when properly laid out. The TSOT23-5 has θ_JA = 100°C/W; at 2W dissipation and 25°C ambient, junction temperature rises ~200°C - exceeding 150°C limit. However, the exposed DRAIN pad must be soldered to ≥1cm² copper pour, reducing effective θ_JA to ~60°C/W, keeping T_J within spec.