Monolithic Power Systems Inc. MP020-5GS-P

Overview

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

For engineers reviewing the MP020-5GS-P datasheet, MP020-5GS-P pinout, MP020-5GS-P application, or MP020-5GS-P equivalent, key selection criteria include its 700V drain rating, SOIC8-7A package thermal performance (θJA = 76°C/W), CC/CV accuracy over temperature, cable compensation capability (2V CP pin max), and integrated protections including OCkP, OVP (6.35V), and OTP (150°C).

Technical Context

The MP020-5GS-P implements primary-side regulation via auxiliary winding voltage sampling at the FB pin with 3.5µs delay after MOSFET turn-off, enabling accurate CV control independent of secondary diode drop. Its DCM detection threshold (120mV falling edge on FB) ensures stable operation across line/load variations.

Constant-current regulation relies on ZCD-based duty-cycle sensing to estimate output current (IO_REF = 0.152A), with internal current limit set at 380mA (typ) and leading-edge blanking (300ns) to reject switching-node noise. The integrated 700V MOSFET features RON = 10Ω (typ) and VBRDSS = 700V, eliminating external HV startup circuitry.

Key Specifications

Pinout & Package

MP020-5GS-P is housed in a SOIC8-7A package (7-pin variant with pin 7 NC), optimized for thermal dissipation (θJA = 76°C/W) and compact offline SMPS layouts. Exposed pad not present; GND pins (2,5,6) provide shared return path for power and signal grounds.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP020-5GS-P, MP021-5GS-P trades 1W output capability for slightly lower cost, while LNK364PG increases BOM complexity and reduces EMI performance but offers broader legacy support and higher breakdown margin.

Availability

MP020-5GS-P is available at Aetrix Electronics and suitable for smartphone charging adapters, wireless earbud case power supplies, and IoT sensor node auxiliary rails requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MP020-5GS-P 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, AC/DC, and motor drive solutions.

The MP020 product line delivers highly integrated primary-side controllers for low-power offline adapters, designed specifically to replace opto-coupler-based feedback while meeting global energy efficiency standards (ERP, CoC, Energy Star).

FAQ

What is the maximum continuous output power achievable with MP020-5GS-P at 230Vac input?

The MP020-5GS-P supports up to 5W continuous output power under 230Vac input conditions, as verified in the typical application circuit (Figure 14) with 1.6mH primary inductance, 60kHz switching, and SOIC8-7A thermal derating. Output power is limited by R_ON (10Ω), junction temperature (150°C), and minimum switching frequency (120Hz) at light loads.

How does the CP pin implement cable compensation, and what external components are required?

The CP pin outputs a DC voltage (0–2V) proportional to load current, derived from ZCD-sampled secondary diode duty cycle. A 1µF ceramic capacitor must be connected from CP to GND as a low-pass filter. The upper resistor (R_UP) of the FB voltage divider is adjusted to convert CP voltage into compensating current, offsetting output cable voltage drop without additional ICs.

Does MP020-5GS-P require an auxiliary winding on the transformer, and what is its function?

Yes-an auxiliary winding is mandatory. It provides sampled voltage to the FB pin for primary-side CV regulation and enables DCM detection. The turns ratio (N_{P_AU}:N_S) sets the FB voltage scaling; for 5V output, typical ratio is 18:8. The auxiliary winding also powers the IC after startup, replacing the internal HV current source once VCC exceeds VCCH.

What protection features are integrated, and how do they behave during fault conditions?

MP020-5GS-P integrates VCC UVLO, over-current protection (OCP), over-voltage protection (OVP at 6.35V), open-circuit protection (OCkP), and over-temperature protection (OTP at 150°C). All protections trigger hiccup-mode restart except OTP, which enters auto-recovery mode-resuming operation only after die temperature falls below 120°C.

Can MP020-5GS-P operate in continuous conduction mode (CCM), and how is DCM enforced?

No-it is designed exclusively for DCM operation. The IC monitors the FB pin for a 120mV falling edge each cycle; failure to detect this edge (indicating CCM) forces immediate shutdown. This hard DCM enforcement ensures predictable CC/CV behavior, simplifies transformer design, and eliminates right-half-plane zero complications.

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

The datasheet recommends R_UP between 50kΩ and 100kΩ for optimal noise immunity and CV regulation accuracy. Values below 50kΩ increase substrate injection current and reduce CV precision; values above 100kΩ raise susceptibility to leakage currents and EMI coupling. A 68kΩ 1% resistor is commonly used in reference designs.

How does the MP020-5GS-P achieve <30mW no-load consumption without compromising startup reliability?

It combines a 550µA internal HV current source (drawn from Drain pin) for initial VCC charging with automatic disable once VCC reaches VCCH (17.3V). During no-load, the IC enters ultra-low-power sleep state-reducing quiescent current to 360µA-and resumes switching only when load demand increases, ensuring reliable startup and sub-30mW standby.