Monolithic Power Systems Inc. MP156GJ-Z

Overview

MP156GJ-Z from Monolithic Power Systems is a primary-side constant-voltage (CV) off-line regulator with integrated 500V/20Ω MOSFET, supporting Buck, Buck-Boost, Boost, and Flyback topologies. It delivers up to 4W output power, achieves <30mW no-load consumption, and features green-mode operation with frequency foldback and peak-current compression for high light-load efficiency - ideal for standby power in home appliances and white goods.

For engineers reviewing the MP156GJ-Z datasheet, MP156GJ-Z pinout, MP156GJ-Z application, or MP156GJ-Z equivalent, key selection criteria include its TSOT23-5 package, 5.3–5.6V VCC operating range, 2.55V feedback reference, 150°C thermal shutdown threshold, and support for non-isolated/isolated topologies without optocoupler.

Technical Context

The MP156GJ-Z implements primary-side regulation using internal error amplifier compensation and ramp-based feedback control that samples FB voltage 6µs after MOSFET turn-off. Its green-mode architecture dynamically reduces switching frequency and peak current under light load to maintain >75% efficiency at 10% load.

It integrates a 500V high-voltage start-up current source on the DRAIN pin, self-supplies via internal VCC regulation with 250mV hysteresis, and employs 350ns leading-edge blanking to suppress current-sense noise. Protection logic includes timer-based OLP (170ms delay at 37kHz), SCP at 450mA, and open-loop detection at 60mV FB voltage.

Key Specifications

Pinout & Package

MP156GJ-Z is packaged in TSOT23-5 - a 2.9mm × 1.6mm surface-mount package with exposed drain pad for thermal enhancement. Pin 1 is VCC, Pin 2 is FB, Pins 3 and 4 are SOURCE (internally tied), and Pin 5 is DRAIN.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP156GJ-Z, MP157GJ-Z extends input ruggedness without changing footprint or control behavior, while LNK3206G trades efficiency and integration for broader legacy compatibility - making MP156GJ-Z optimal for new designs prioritizing ultra-low standby power and topology flexibility.

Availability

MP156GJ-Z is available at Aetrix Electronics and suitable for home appliance control boards, industrial sensor nodes, white goods displays, and USB-C adapter auxiliary rails requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP156GJ-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP156 product line targets cost-sensitive, space-constrained off-line power conversion applications requiring high integration, ultra-low standby power, and primary-side regulation - specifically addressing demands in smart home, industrial IoT, and energy-efficient consumer electronics.

FAQ

What is the maximum recommended output power for MP156GJ-Z in TSOT23-5 package?

The MP156GJ-Z in TSOT23-5 is rated for up to 4W output power under proper thermal conditions. Derating is required above +85°C ambient due to its 1W continuous power dissipation limit and 100°C/W θ_JA; for sustained 4W operation, use forced airflow or copper pour under the exposed drain pad.

Does MP156GJ-Z require an external VCC capacitor, and what value is recommended?

Yes - a 1–4.7μF ceramic capacitor is required between VCC and SOURCE pins. This capacitor sustains control circuitry during light-load periods when the internal HV current source is inactive; values below 1μF risk UVLO cycling, while >10μF delays startup and increases inrush stress.

How does MP156GJ-Z achieve <30mW no-load power consumption without an auxiliary winding?

It uses an internal high-voltage current source on the DRAIN pin to charge the VCC capacitor during each switching cycle, combined with green-mode frequency foldback and peak-current compression. At no-load, frequency drops below 10kHz and peak current falls to ~100mA, minimizing both switching and conduction losses.

Can MP156GJ-Z be used in isolated flyback topologies without optocoupler feedback?

Yes - it supports indirect primary-side sensing in flyback mode using a third-winding or auxiliary winding to sample reflected output voltage. The FB pin monitors this sampled signal, enabling ±5% regulation without optocoupler or secondary-side references, as verified in MPS Application Note AN109.

What is the purpose of the dual leading-edge blanking times (350ns and 180ns)?

The 350ns blanking applies during normal switching to suppress gate-drive-induced current-sense noise; the shorter 180ns blanking activates specifically during short-circuit protection to allow faster fault detection while still rejecting initial turn-on transients - ensuring reliable SCP without nuisance tripping.

Is MP156GJ-Z compatible with both CCM and DCM operation, and how does it manage mode transition?

Yes - it operates in both modes. Minimum off-time (18µs) and peak-current limit (290mA typ) define the CCM/DCM boundary. As load decreases, frequency foldback and peak-current compression automatically shift operation toward DCM, maintaining regulation while reducing losses - no external mode-select components are needed.