Monolithic Power Systems Inc. EV173A-J-00A

Overview

EV173A-J-00A from Monolithic Power Systems is an evaluation board for the MP173AGJ primary-side constant voltage regulator IC, configured in a buck topology to deliver 12 V / 250 mA (3 W) from universal AC input (85–265 VAC). It demonstrates non-isolated off-line regulation without optocoupler, achieves >75% full-load efficiency, meets EN55022 conducted EMI limits, and passes IEC61000-4-5 ±1 kV line-to-line surge testing.

For engineers reviewing the EV173A-J-00A datasheet, EV173A-J-00A pinout, EV173A-J-00A application, or EV173A-J-00A equivalent, this board enables rapid validation of MP173A-based buck regulators in low-power universal-input applications-particularly where cost-sensitive, compact, and EMI-compliant standby or auxiliary supplies are required.

Technical Context

The EV173A-J-00A implements a primary-side-controlled buck converter using the MP173AGJ IC in TSOT23-5 package, eliminating secondary-side feedback components. It operates with variable switching frequency (34.2–36.0 kHz across input range) and integrates internal high-voltage startup current source with external VCC bias via R2/C2/D1 network.

EMI performance is enhanced via π-filter (C4/L1/C5), ceramic + electrolytic output staging (C6/C7), and optimized layout per single-sided PCB (68 mm × 28 mm × 17 mm). Protection features-including SCP, OLP, OTP, open-loop, and VCC UVLO-are exercised and verified on-board during transient and fault testing.

Key Specifications

Availability

EV173A-J-00A is available at Aetrix Electronics and suitable for home appliance auxiliary power, industrial control logic supply, and consumer electronics standby power requiring stable component supply and fast design validation.

Supply support for EV173A-J-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 focus on efficiency, integration, and reliability across power management, motor drive, and interface solutions.

The EV173A-J-00A belongs to MPS's evaluation board product line for primary-side regulation ICs, designed to accelerate development of cost-sensitive, non-isolated AC/DC converters targeting white goods, smart home devices, and industrial controls.

FAQ

Is EV173A-J-00A still in production?

No. The EV173A-J-00A is End-of-Life per official MPS documentation, with direct migration path to EV174A-J-00A. Aetrix Electronics maintains limited legacy stock for design continuity but recommends evaluating EV174A-J-00A for new designs due to updated performance and long-term availability.

What topology does EV173A-J-00A implement?

The board implements a buck converter topology using the MP173AGJ IC. Though MP173A supports Buck, Buck-Boost, Boost, and Flyback, the EV173A-J-00A is specifically configured as a non-isolated buck regulator delivering 12 V from universal AC input, with no transformer isolation or optocoupler.

Can EV173A-J-00A be used for isolated designs?

No. This board is explicitly non-isolated and lacks reinforced insulation, safety-rated transformers, or creepage/clearance provisions for isolated applications. It is intended only for primary-side-regulated, low-risk auxiliary or standby supplies where galvanic isolation is not required by safety standards.

What protections are demonstrated on this board?

The board validates five key protections: short-circuit protection (SCP), over-load protection (OLP), thermal shutdown (OTP), open-loop protection, and VCC under-voltage lockout (UVLO). Waveform test results for entry and recovery of each are documented in the official EVB report (pages 11–12).

Does EV173A-J-00A meet regulatory EMI standards?

Yes. The board meets EN55022 Class A conducted emissions limits and shows improved radiated emissions versus prior MP173-based designs. Test data for both L- and N-line CE plots is provided in the reference document (page 9), confirming compliance without external filtering beyond the onboard π-filter.

What is the role of R6 on the board?

R6 is a 20 kΩ dummy load resistor placed across the 12 V output to prevent output voltage rise under no-load conditions. It ensures stable regulation and prevents overvoltage when the main load is disconnected, a known behavior of primary-side controllers lacking secondary feedback.