Monolithic Power Systems Inc. MP020-5GS-Z

Overview

MP020-5GS-Z from Monolithic Power Systems is an offline, primary-side flyback controller IC with integrated 700V MOSFET, delivering precise constant-voltage (4.0 V ±3%) and constant-current (0.152 A) regulation without opto-coupler or secondary feedback. It operates in discontinuous conduction mode (DCM) using variable off-time peak-current control, supports ≤5 W adapter output power at 85–265 V_AC, and achieves <30 mW no-load consumption for energy-efficient low-power chargers.

For engineers reviewing the MP020-5GS-Z datasheet, MP020-5GS-Z pinout, MP020-5GS-Z application, or MP020-5GS-Z equivalent, key selection criteria include its 700V drain rating, SOIC8-7A package thermal resistance (θ_JA = 76 °C/W), programmable cable compensation via CP pin, and built-in protections including OVP (6.35 V), OCkP, OTP (150 °C), and VCC UVLO (6.3 V/17.3 V).

Technical Context

The MP020-5GS-Z implements primary-side regulation by sampling auxiliary winding voltage at the FB pin 3.5 µs after MOSFET turn-off to maintain CV accuracy, while detecting zero-current crossing (ZCD) to enable CC mode with load-independent current regulation. Its internal 700V MOSFET eliminates external high-voltage switch requirements, and variable switching frequency (120 Hz min) provides natural EMI spectrum shaping.

Startup relies on a 550 µA high-voltage current source from the Drain pin, transitioning to auxiliary winding supply once VCC reaches 17.3 V; shutdown occurs below 6.3 V. Protection logic includes leading-edge blanking (300 ns), open-circuit detection (120 mV FB falling edge), and hiccup-mode recovery after OVP or OCkP faults.

Key Specifications

Pinout & Package

MP020-5GS-Z is housed in a SOIC8-7A package (8-pin, 7.5 mm × 4.9 mm, 1.27 mm pitch), optimized for thermal dissipation (θ_JA = 76 °C/W) and board-level EMI control via GND pin placement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side flyback controller applications.

Compared with MP020-5GS-Z, MP021-5GS-Z trades 1 W output capability for slightly lower cost, while LNK304DG sacrifices cable compensation and EMI flexibility for broader legacy compatibility - neither matches the integrated 5 W/30 mW/cable-compensation triad of the MP020-5GS-Z.

Availability

MP020-5GS-Z is available at Aetrix Electronics and suitable for cell phone chargers, USB wall adapters, and standby power supplies requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP020-5GS-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 over 20 years of leadership in DC/DC converters, LED drivers, and AC/DC controllers.

The MP020 product line targets ultra-low-power offline adapters and chargers, emphasizing integration, EMI performance, and regulatory compliance without secondary-side components.

FAQ

What is the maximum continuous output power achievable with MP020-5GS-Z?

The MP020-5GS-Z supports up to 5 W output power under universal AC input (85–265 V_AC) in open-frame configuration, verified per manufacturer specifications. This assumes proper thermal design (SOIC8-7A θ_JA = 76 °C/W), 1.6 mH transformer inductance, and operation within -40°C to +125°C junction temperature range. Exceeding 5 W risks thermal shutdown or reduced reliability.

How does the CP pin implement cable compensation?

The CP pin outputs a DC voltage (0–2 V) proportional to load current, derived from ZCD duty-cycle sampling. This voltage sources current into the FB resistor divider, effectively lowering the FB reference voltage as load increases - counteracting voltage drop across USB cables and maintaining regulated output voltage within ±1% across 0–1 A.

Can MP020-5GS-Z operate without an auxiliary winding?

No. The MP020-5GS-Z requires an auxiliary winding to generate VCC supply and provide feedback voltage to the FB pin. Without it, the IC cannot sustain operation after initial HV start-up current source disengages at VCC = 17.3 V, and CV/CC regulation fails due to missing sampling reference.

What is the purpose of the three GND pins (pins 2, 5, 6)?

Pins 2, 5, and 6 are separate GND terminals assigned to analog ground (FB/CP), power ground (Drain return), and VCC ground respectively. This separation minimizes noise coupling between high-dV/dt switching paths and sensitive feedback circuitry, improving CV regulation stability and EMI performance in compact layouts.

Does MP020-5GS-Z support continuous conduction mode (CCM)?

No. The MP020-5GS-Z is designed exclusively for discontinuous conduction mode (DCM) operation. Its DCM detection circuit monitors the FB pin for ≥120 mV falling edges each cycle; failure to detect this triggers shutdown, preventing CCM entry and ensuring predictable transformer reset and ZCD-based CC control.

What is the minimum recommended value for the FB voltage divider's upper resistor (R_UP)?

The datasheet specifies R_UP should be between 50 kΩ and 100 kΩ for optimal CV regulation and noise immunity. Values below 50 kΩ increase substrate injection current and degrade light-load regulation; values above 100 kΩ raise susceptibility to EMI-induced errors on the FB node.

How does the MP020-5GS-Z achieve <30 mW no-load consumption?

It combines a low-quiescent-current design (410 µA at VCC = 20 V), internal HV start-up current source (550 µA), and automatic transition to auxiliary winding supply - eliminating external start-up resistors and minimizing bias losses. The variable-frequency DCM operation further reduces switching losses at light loads.