MP1584EN PCB Design Guide: Footprint, Pinout, and Alternatives
3 A peak 28 V-input buck converter on countless cheap modules
The MP1584EN is the step-down converter behind a huge share of the small, cheap buck modules sold on AliExpress, Amazon, and eBay. It takes 4.5 V to 28 V in, switches at a programmable 100 kHz to 1.5 MHz, and idles at a 100 uA operational quiescent current — a combination that made it the default choice for shrinking 12 V or battery rails down to 5 V or 3.3 V in hobby and low-volume designs.
Two things to know before designing it in. First, MPS has flagged the MP1584 as Not Recommended for New Designs: it remains in production for existing customers, but MPS points new designs to the MP2338GTL. Second, the full datasheet PDF sits behind a login on the MPS site, so the anonymous product page is the reference linked here — pull the gated datasheet for electrical tables before finalizing a layout.
Most MP1584 disappointments trace to the same handful of issues: reading the 3 A headline as a continuous rating, skimping on the external catch diode, fighting the minimum on-time at high switching frequency, or building on a counterfeit module. Each is covered below.
What breaks boards
It is NRND — pick a successor for new boards
The MPS product page carries a NOT RECOMMENDED FOR NEW DESIGNS banner. The part is still in production for existing customers, so modules will keep shipping for a while, but a new custom layout should start from the MPS-recommended MP2338GTL or a synchronous part like the MP2315 rather than lock in a chip already on the way out.
"3 A" is a peak output rating, not what you get continuously
The product page advertises 3 A output, and module listings repeat it without qualification. In an exposed-pad SOIC-8 with the thin copper typical of cheap modules, thermal limiting arrives well before that — plan on roughly 1.5 to 2 A continuous with decent copper pour under the pad, less in still air at high Vin-to-Vout ratios. The internally set switch current limit is specified only in the login-gated datasheet, so verify it there before counting on peak numbers.
Non-synchronous topology needs an external catch Schottky
The MP1584 has no internal low-side switch, so a freewheeling Schottky (SS34-class on most modules) carries the inductor current during the off-time. Diode selection and placement drive efficiency and output ripple: keep the diode-to-SW-to-input-cap loop tight, and size the diode for the full output current, not the average diode current at your duty cycle alone.
Minimum on-time limits high step-down ratios at high fsw
Switching frequency is programmable from 100 kHz to 1.5 MHz via the frequency-set resistor. Running fast shrinks the inductor, but at large Vin-to-Vout ratios the required on-time can fall below the controller minimum, forcing pulse skipping and audible or measurable ripple. If you are dropping 24 V to 3.3 V, choose a lower fsw; check the minimum on-time figure in the MPS datasheet against your duty cycle.
Set the output with the FB divider — pull the reference from the datasheet
Output voltage is programmed by a resistor divider from VOUT to the FB pin, and a feedforward capacitor across the top resistor improves transient response. The FB reference voltage is not published on the anonymous product page, so take its exact value (and the divider design procedure) from the login-gated MPS datasheet rather than from module schematics or memory — clone boards do not always copy the divider correctly.
Cheap modules carry remarked chips and marginal layouts
The MP1584's popularity made it a counterfeiting target: modules with remarked or out-of-spec chips are common, and even genuine ones often pair the part with a loose SW-node loop that rings and radiates. If a module misbehaves, suspect the module before the design. For a custom layout, keep the SW loop minimal, place the input capacitor tight against the IC, and follow the pad-layout guidance in the gated datasheet for the exposed pad.
Key specifications
| Parameter | Value | Source |
|---|---|---|
| Vin range | 4.5 V to 28 V | https://www.monolithicpower.com/en/mp1584.html - Features ('Wide 4.5V to 28V Operating Input Range') |
| fsw range | Programmable 100 kHz to 1.5 MHz (1.5 MHz nominal per product title) | https://www.monolithicpower.com/en/mp1584.html - Features ('Programmable Switching Frequency from 100kHz to 1.5MHz') |
| Iq | 100 uA operational quiescent current | https://www.monolithicpower.com/en/mp1584.html - Description ('A 100uA operational quiescent current allows use in battery-powered applications') |
| Package thermal pad | Thermally enhanced SOIC8E (exposed-pad SOIC-8); detailed pad-layout guidance is in the gated datasheet | https://www.monolithicpower.com/en/mp1584.html - Description ('available in a thermally enhanced SOIC8E package') |
Verified against the manufacturer datasheet on 2026-07-09. Confirm the current revision before production use.
Alternatives
- MP2338GTL — the successor MPS recommends for new designs now that the MP1584 is NRND — synchronous, and the right starting point for a fresh layout.
- MP2315 — synchronous buck in the same family: no external catch diode, runs cooler at the same load, and common on newer modules.
- TPS54331 — TI's 28 V, 3 A non-synchronous buck with a well-documented design flow (WEBENCH, full datasheet); like the MP1584 it needs an external catch diode between PH and GND.
- LM2596 — the older 150 kHz generation: needs a physically huge inductor, but the slow switching makes it tolerant of sloppy layout and it is easy to source.
Common questions
- How much current can an MP1584 module really deliver?
- Treat the advertised 3 A as a peak output rating. In the exposed-pad SOIC-8 on a typical cheap module, thermal limiting sets in around 1.5 to 2 A continuous — less with high Vin-to-Vout ratios or poor airflow. Check the internally set current limit in the MPS datasheet before relying on peak numbers.
- Is the MP1584 discontinued?
- Not discontinued, but MPS marks it NOT RECOMMENDED FOR NEW DESIGNS. It stays in production for existing customers, and MPS recommends the MP2338GTL for new designs. Existing modules keep working; new custom boards should specify a successor.
- MP1584 or LM2596 — which should I use?
- The MP1584 switches up to 1.5 MHz, so it uses a far smaller inductor and idles at 100 uA, while the LM2596 runs at a fixed low frequency with a large inductor but tolerates rough layouts. For a genuinely new design, neither is ideal: the MP1584 is NRND, so look at the MP2338GTL or a synchronous part like the MP2315 first.
- Why is my MP1584 module noisy or unstable?
- Cheap modules frequently carry remarked or counterfeit chips and marginal layouts with a loose SW-node loop, which rings and radiates. Swap in a known-good module before debugging your circuit. If you laid out the board yourself, tighten the SW loop, move the input capacitor against the IC, and confirm the FB divider against the MPS datasheet.