Monolithic Power Systems Inc. EV174A-J-00A

Overview

EV174A-J-00A from Monolithic Power Systems is an evaluation board designed to demonstrate the MP174AGJ primary-side constant voltage regulator in a buck topology, delivering 12 V / 300 mA (3.6 W) from universal 85–265 VAC input, with >75% full-load efficiency, <30 mW no-load consumption, and EN55022-compliant conducted EMI performance.

For engineers reviewing the EV174A-J-00A datasheet, EV174A-J-00A pinout, EV174A-J-00A application, or EV174A-J-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, surge immunity (IEC61000-4-5), and thermal shutdown are critical.

Technical Context

The EV174A-J-00A implements a primary-side-controlled buck converter using the MP174AGJ IC in TSOT23-5 package, eliminating secondary-side feedback components. It operates with variable switching frequency (22.2–24.4 kHz across input range) and integrates internal high-voltage startup current source with external VCC bias via R2/C2/D1 network.

EMI suppression relies on a π-filter (C4/L1/C5), ceramic output filtering (C7), and optimized PCB layout per single-sided top/bottom layer drawings. Protection logic includes cycle-by-cycle over-current detection, open-loop fault latching, and thermal shutdown triggered at ~150°C.

Key Specifications

Availability

EV174A-J-00A is available at Aetrix Electronics and suitable for home appliance control modules, industrial sensor interface power supplies, and consumer electronics standby rails requiring stable component supply, quick-turn evaluation, and regulatory-compliant EMI performance.

Supply support for EV174A-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 core expertise in DC/DC conversion, LED drivers, and motor control solutions.

The MP174A product line delivers primary-side constant voltage regulation for non-isolated offline AC/DC applications, targeting cost-sensitive, space-constrained designs where optocoupler elimination and fast time-to-test are essential.

FAQ

What topology does the EV174A-J-00A implement?

The EV174A-J-00A is configured exclusively as a buck regulator using the MP174AGJ IC. Though the MP174A supports Buck-Boost, Boost, and Flyback topologies, this evaluation board's schematic, component placement, and test data confirm fixed buck operation with D5 as freewheeling diode and L2 as series inductor.

Does the board include safety agency certification?

No - the EV174A-J-00A is an engineering prototype not certified by UL, CE, or other agencies. MPS explicitly warns that all testing must use an isolation transformer for AC input, and the board lacks reinforced insulation or creepage/clearance compliance required for end-product certification.

How is output voltage set and trimmed?

Output voltage is set by resistor divider R1 (19.1 kΩ) and R4 (4.99 kΩ) across sample-hold capacitor C1 (470 nF). The ratio yields ~12 V nominal at FB pin of MP174AGJ; trimming requires replacing R1 or R4 with precision resistors - no onboard potentiometer or DAC is provided.

Can the board operate at 2 kV surge level?

Yes - the reference schematic in Figure 4 shows modification with two 10 Ω/1 W fuse resistors (F1 and F2) enabling 2 kV line-to-line surge compliance per IEC61000-4-5. The base EV174A-J-00A Rev.1.0 board passes only 1 kV without this change.

What is the role of R6 on the board?

R6 (20 kΩ, 1206) serves as a dummy load to prevent output voltage rise under no-load conditions. Without it, the 12 V rail can exceed specification due to light-load regulation drift inherent in primary-side control architecture.

Which protection features are demonstrated on this board?

The board validates short-circuit protection (SCP), over-load protection (OLP), open-loop protection, thermal shutdown (OTP), and VCC under-voltage lockout (UVLO) through oscilloscope waveforms in Sections 11–12 of the reference document, including entry/recovery timing and fault latch behavior.