Monolithic Power Systems Inc. EVHF500-15-S-00A

Overview

EVHF500-15-S-00A from Monolithic Power Systems is an evaluation board for the HF500-15GS multi-mode flyback regulator IC, designed to demonstrate a universal-input (85–265 VAC), 12 V/1 A offline AC/DC adapter solution. It integrates a 700 V/4.5 Ω avalanche-rugged MOSFET and controller in SOIC8, delivers 12 W output power at ≥79% average efficiency, meets EN55022 Class B conducted EMI, and implements full protection including OVP, SCP, OTP, and brown-in/out.

For engineers reviewing the EVHF500-15-S-00A datasheet, EVHF500-15-S-00A schematic, EVHF500-15-S-00A layout, or EVHF500-15-S-00A test results, this board supports rapid validation of flyback topology design, EMI compliance testing, thermal performance assessment under universal input conditions, and multi-protection feature verification in low-power adapter applications.

Technical Context

The EVHF500-15-S-00A implements a single-stage, current-mode flyback converter with fixed-frequency operation and frequency foldback at light load. Its control architecture includes built-in slope compensation, burst mode for standby power reduction, and jittering to suppress EMI peaks.

Primary-side regulation uses TL431 + PC817A optocoupler feedback with programmable OLP delay and soft-start. Input stage features MOV (RV1), X-cap (CX1), common-mode chokes (L2/L3), and differential-mode filter (L1/C2/C4) - all validated for EN55022 Class B compliance across 115 VAC and 230 VAC full-load conditions.

Key Specifications

Availability

EVHF500-15-S-00A is available at Aetrix Electronics and suitable for universal-input AC/DC adapter development, EN55022-compliant power supply qualification, and flyback controller reference design validation requiring stable component supply and documented thermal/EMI performance.

Supply support for EVHF500-15-S-00A 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 expertise in DC/DC converters, LED drivers, motor drivers, and AC/DC controllers.

This evaluation board supports MPS's HF500 series - a family of integrated flyback regulators targeting cost-sensitive, low-to-mid power (<25 W) offline adapters where high avalanche ruggedness, EMI robustness, and multi-protection integration are critical.

FAQ

What is the primary function of the EVHF500-15-S-00A evaluation board?

The EVHF500-15-S-00A is a fully assembled, tested demonstration platform for the HF500-15GS flyback controller IC. It provides a working 12 V/1 A universal-input AC/DC power supply that validates key system-level behaviors - including efficiency, EMI performance, thermal distribution, and protection response - without requiring custom PCB design or component sourcing.

Does the board include input EMI filtering components?

Yes. The board integrates a complete front-end EMI filter: a 275 VAC MOV (RV1), 100 nF X-capacitor (CX1), 1.0 mH common-mode choke (L1), two magnetic beads (L2/L3), and damping resistor (R22). These components collectively meet EN55022 Class B conducted emissions limits across 150 kHz–30 MHz.

How is output voltage regulation implemented?

Regulation uses primary-side sensing via TL431 shunt regulator (U3) and PC817A optocoupler (U2) on the secondary side. Feedback resistors R17/R18/R19 set the 12 V output threshold, while R15/C11 form the compensation network. This isolated feedback loop ensures tight line/load regulation without auxiliary winding dependency.

What protection features are demonstrated on this board?

The board demonstrates six hardware-based protections: brown-in/out (via R6/R7/R8/C13), over-voltage (OVP via optional D1/R3/C1/Q1 circuit), short-circuit (SCP), cycle-by-cycle current limiting, over-temperature (OTP via external RT2 thermistor option), and latch-off on TIMER pin fault - all enabled by the HF500-15GS IC.

Can the board be used for thermal testing?

Yes. Thermal imaging data is provided in the reference design document for both 85 VAC and 265 VAC full-load conditions. Key hotspots - HF500-15GS (SOIC8), BYV28-100 rectifier (D8), and transformer T1 - are identified, and the board uses 1 oz copper layers to reflect real-world thermal performance in enclosed adapter housings.

Is the transformer included, and what are its key specs?

Yes, EE19 flyback transformer T1 is mounted and fully specified: 2.45 mH ±10% primary inductance, <120 µH leakage inductance, 3500 VAC isolation between primary and secondary, and triple-insulated secondary winding (Φ0.45 mm TIW). Its winding diagram and tape-layer construction are documented for replication.