Monolithic Power Systems Inc. MP100LGN-Z

Overview

MP100LGN-Z from Monolithic Power Systems is an inductor-less offline AC/DC regulator IC designed for bias power generation in low-power off-line applications. It accepts universal AC input (85–305 VAC), delivers adjustable DC output (1.5–15 V) up to 220 mA, achieves <100 mW standby power, and integrates thermal shutdown, OVP, SCP, and active bleeder circuitry. Used in wall switches, ZigBee/Z-Wave power supplies, and standby rails.

For engineers reviewing the MP100LGN-Z datasheet, MP100LGN-Z pinout, MP100LGN-Z application, or MP100LGN-Z equivalent, this page provides verified functional identity, SOIC-8 EP package mapping, confirmed 8-pin terminal roles, real-world regulation performance (0.1% load regulation, 60 dB PSRR), and validated alternatives for low-power offline bias supply design.

Technical Context

The MP100LGN-Z implements a proprietary smart charging architecture that samples AC line voltage only within a narrow "charging window" (31.5–34 V), minimizing conduction time and enabling ultra-low standby power. Its internal NMOS switch features controlled slew rates (130–200 µs/A) to meet conducted EMI standards with only a 220 nF X-capacitor.

It operates as a two-stage regulator: first, it charges the external VD capacitor from AC line during low-voltage intervals; second, an integrated LDO stage regulates stable VOUT from VD. Protection logic includes auto-restart over-current/short-circuit response, active bleeder activation below 14.4 V on VD, and precise 160°C thermal shutdown with 20°C hysteresis.

Key Specifications

Pinout & Package

MP100LGN-Z is housed in an SOIC-8 EP (exposed pad) package. The exposed thermal pad must be soldered to a large GND copper area for thermal dissipation and surge robustness.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar offline inductor-less regulator applications.

Compared with MP101LGN-Z, the MP100LGN-Z trades 80 mA output headroom for lower quiescent current and reduced thermal stress in compact enclosures; versus LNK3206P, it eliminates magnetics and simplifies certification but caps usable power at ~260 mW.

Availability

MP100LGN-Z is available at Aetrix Electronics and suitable for smart wall switches, ZigBee/Z-Wave modules, and IoT gateway standby rails requiring stable component supply, RoHS-compliant packaging, and long-term industrial availability.

Supply support for MP100LGN-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 across Asia and North America.

The MP100L product line targets ultra-low-power offline bias supply applications, delivering inductor-less AC/DC conversion for smart home, industrial IoT, and energy-efficient standby systems.

FAQ

What is the minimum VD capacitor value required for stable 12 V / 20 mA operation?

A 220 µF/35 V aluminum electrolytic capacitor is specified in the typical application circuit. This value ensures ≤2 V ripple on VD under full-load conditions with a full-bridge rectifier and 10 ms discharge time constant. Smaller values risk VD collapse below 7.0 V, triggering UVLO shutdown.

Can MP100LGN-Z operate directly from 230 VAC without a bridge rectifier?

No. The device requires rectified DC input on VIN. It is designed to interface with the output of a bridge rectifier (e.g., MB6S). Direct AC connection will exceed absolute maximum ratings and cause immediate failure.

How does the active bleeder improve system reliability during AC removal?

When AC is disconnected, parasitic capacitance maintains residual voltage on VIN. The active bleeder activates when VD falls below 14.4 V, discharging this stored energy through a 270 µA current sink-ensuring rapid, predictable restart upon reapplication of AC without latch-up.

Is the PG pin compatible with 3.3 V logic microcontrollers?

Yes. PG is open-drain and requires an external pull-up resistor. When pulled to 3.3 V, it asserts logic-high at ≥2.64 V (80% of 3.3 V), meeting standard CMOS input thresholds. Delay remains fixed at 245 µs regardless of pull-up voltage.

What is the impact of omitting the exposed thermal pad connection?

Omitting the exposed pad connection increases θJA from 50°C/W to >70°C/W, raising junction temperature by ~15°C at 200 mW dissipation. This reduces thermal margin, risks premature thermal shutdown, and degrades surge immunity-soldering the pad to ≥1 cm² GND copper is mandatory.

Does MP100LGN-Z support output voltages below 3.3 V?

Yes. The FB reference is 1.235 V, and the datasheet confirms operation down to 1.5 V using appropriate RUP/RLW ratios. However, output below 3.3 V reduces available headroom for dropout and may limit load current due to LDO thermal constraints at high input voltages.

Why is a fuse resistor recommended instead of a standard fusible resistor?

A 20 Ω fuse resistor limits peak inrush current during startup and improves surge test margin by delaying entry into the charging window. Standard fusible resistors lack the precise resistance tolerance and surge-withstand rating needed to reliably trigger the 86 V fast-turnoff threshold without nuisance tripping.