Monolithic Power Systems Inc. EV174A-S-00A

Overview

EV174A-S-00A from Monolithic Power Systems is an evaluation board demonstrating the MP174AGS primary-side constant voltage regulator in a buck topology, delivering 12V/300mA (3.6W) from universal 85–265VAC input, with >75% full-load efficiency, EN55022-compliant conducted EMI, and IEC61000-4-5 1kV surge immunity.

For engineers reviewing the EV174A-S-00A datasheet, EV174A-S-00A pinout, EV174A-S-00A application, or EV174A-S-00A equivalent, this board enables rapid validation of non-isolated offline CV regulation for cost-sensitive, low-power AC/DC conversion where optocoupler-free design, <30mW no-load consumption, and thermal/overload/surge robustness are critical.

Technical Context

The EV174A-S-00A implements a primary-side-controlled buck regulator using the MP174AGS IC, eliminating optocouplers and secondary-side feedback. It operates across 85–265VAC input with fixed 12V output and supports line-to-line 1kV surge testing per IEC61000-4-5 at 230VAC.

EMI performance is enhanced via a π-filter (C4–L1–C5), ceramic hold capacitor (C1), and optimized layout; thermal management achieves 70.6°C max case temperature at 265VAC full load. Protection features include SCP, OLP, OTP, open-loop, and VCC UVLO-implemented entirely by the MP174AGS.

Key Specifications

Availability

EV174A-S-00A is available at Aetrix Electronics and suitable for home appliance power supplies, industrial control auxiliary rails, and consumer electronics standby converters requiring stable component supply, fast prototyping cycles, and regulatory-compliant reference designs.

Supply support for EV174A-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 conversion, LED drivers, motor drivers, and AC/DC controllers.

The MP174A product line delivers primary-side constant voltage regulation for non-isolated offline applications, targeting cost-sensitive, space-constrained AC/DC adapters and auxiliary power supplies in white goods and consumer electronics.

FAQ

What is the maximum output power demonstrated by the EV174A-S-00A?

The EV174A-S-00A evaluation board delivers up to 3.6W (12V/300mA) continuously across 85–265VAC input. This rating is validated with thermal derating applied above 70°C ambient and confirmed by test data showing stable regulation and <2% load variation under full load conditions.

Does the board support topologies other than buck?

No-the EV174A-S-00A is specifically configured as a buck regulator. While the underlying MP174AGS IC supports buck-boost, boost, and flyback topologies, this evaluation board's schematic, layout, and component selection (e.g., STTH1R06 freewheeling diode, L2 inductor value) are optimized exclusively for buck operation.

How is EMI performance improved over the MP174 reference design?

EMI improvement is achieved through a revised π-filter (C4–L1–C5), tighter layout routing, and optimized snubber components. Test results show compliance with EN55022 conducted limits across 150kHz–30MHz, with margin exceeding the MP174 baseline by ≥6dB in peak amplitude at 1–10MHz.

What protections are implemented and how are they verified?

All MP174AGS-integrated protections-short-circuit (SCP), over-load (OLP), open-loop, thermal shutdown (OTP), and VCC UVLO-are validated on the board. Waveform captures (pages 11–12) confirm clean entry/recovery behavior for each fault mode under real operating conditions.

Can the board be used for safety-certified final designs?

No-the EV174A-S-00A is an engineering prototype not agency-approved (e.g., UL, CE). It lacks reinforced insulation, creepage/clearance certification, and production-grade safety markings. Users must implement isolation transformers during testing and redesign for safety compliance per IEC62368-1 before commercial deployment.

What external components define the 12V output voltage?

The output voltage is set by the R1/R4 resistor divider (19.1kΩ and 4.99kΩ) connected to the FB pin of U1 (MP174AGS), sampling voltage across hold capacitor C1 (470nF). This network establishes precise 12V regulation without secondary feedback components.