Monolithic Power Systems Inc. EVHF500-7-S-00A

Overview

EVHF500-7-S-00A from Monolithic Power Systems is an evaluation board for the HF500-7 multi-mode flyback regulator IC, designed to demonstrate a universal-input (85–265 VAC), dual-output offline SMPS delivering 12 V/0.3 A and 5 V/0.3 A (5.1 W total). It integrates a 700 V avalanche-rugged MOSFET and controller in SOIC-8, supports EN55022 Class B conducted EMI compliance, and includes brown-in/out, OVP, SCP, OTP, and cycle-by-cycle current limiting.

For engineers reviewing the EVHF500-7-S-00A datasheet, EVHF500-7-S-00A pinout, EVHF500-7-S-00A application, or EVHF500-7-S-00A equivalent, this board enables rapid validation of fixed-frequency current-mode flyback designs with burst-mode low standby power, frequency jittering for EMI reduction, and programmable soft-start-key for cost-sensitive, safety-certified AC/DC adapters and IoT power supplies.

Technical Context

The EVHF500-7-S-00A implements a single-stage flyback topology using the HF500-7 IC, which embeds a 700 V/12 Ω MOSFET and current-mode controller with built-in slope compensation. Its transformer (EE16 core, 3.5 mH primary inductance) supports dual isolated outputs with TIW-wound auxiliary and feedback windings.

Input stage features a bridge rectifier (D1–D4), differential-mode EMI filter (C1/C4/L1), fusible resistor (FR1), and magnetic beads (L2/L3); output regulation uses TL431K + PC817A optocoupler feedback with programmable B/O detection via R3/R4/R5/C2 and VCC supply derived from R8/C7/D6.

Key Specifications

Availability

EVHF500-7-S-00A is available at Aetrix Electronics and suitable for AC/DC adapter development, IoT edge node power design, and industrial control module prototyping requiring stable component supply, fast turnaround, and pre-validated safety margins.

Supply support for EVHF500-7-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 power management ICs, with expertise in integrated DC/DC, AC/DC, LED drivers, and motor drivers for consumer, industrial, and automotive markets.

The HF500-7 product line targets cost-optimized, safety-compliant offline flyback converters for sub-10 W applications, emphasizing integration (700 V MOSFET + controller), EMI robustness, and low no-load consumption.

FAQ

What is the primary function of the EVHF500-7-S-00A evaluation board?

The EVHF500-7-S-00A is a fully assembled, tested demonstration platform for the HF500-7 multi-mode flyback regulator IC. It delivers two isolated DC outputs (12 V/0.3 A and 5 V/0.3 A) from universal AC input and validates key features including EN55022 Class B EMI compliance, burst-mode operation, and comprehensive protection schemes.

Can the EVHF500-7-S-00A be used for production-level power supply design?

No-it is strictly an evaluation board intended for functional verification, reference design derivation, and parameter tuning. Production use requires full safety certification (e.g., UL/IEC 62368-1), layout review, thermal validation, and component requalification per end-equipment requirements.

How is input brown-in/out implemented on this board?

Brown-in/out detection is configured via resistive divider R3/R4/R5 and capacitor C2 connected to the B/O pin of U1 (HF500-7). Thresholds are programmable; the function can be disabled by connecting a ~100 kΩ resistor between VCC and B/O to reduce no-load power consumption.

What transformer is used, and why is its winding configuration critical?

The board uses custom EE16 transformer FX0378 with 3.5 mH primary inductance, <100 µH leakage inductance, and triple-insulated windings (N4, N3) for reinforced isolation. Precise winding order, polarity (anti-clockwise N4), and parallel secondary windings (N5/N6) ensure cross-regulation, safety margin, and optimal efficiency under varying loads.

Does the board support adjustable output voltages?

No-the 12 V and 5 V outputs are fixed by the feedback resistor network (R14/R15/R16/R18) and TL431K reference. Output voltage adjustment requires modifying these resistors and revalidating regulation accuracy, loop stability, and protection thresholds across input and load ranges.

What safety certifications has the EVHF500-7-S-00A itself achieved?

The board is not certified as a standalone end-product. However, its design meets EN55022 Class B conducted EMI limits and incorporates safety-rated components (Y-capacitor CY1, TIW transformer windings, reinforced isolation barriers), enabling faster path to IEC/UL 62368-1 certification when adapted into a properly enclosed, labeled system.