Guides / Finding equivalent parts · Data from 22 October 2026

How to find an equivalent electronic component

An equivalent part is one you can put on the same pads without changing anything else on the board. For a diode or a MOSFET that comes down to a few numbers. For an op-amp or a timer, a part in the same package from the same family can still behave differently. Here are four common parts we cross-referenced on 22 October 2026, and what each search found.

Short answer

Discretes are easy to cross-reference. For MOSFETs and diodes a handful of specs decide it, and most popular parts have several drop-in equivalents in stock.
The same part number from another manufacturer is usually the cheapest equivalent. An AO3400 or SS34 from a second source cost a fraction of the original.
For ICs, "same package, same category" is not enough. An MCP6002 fits the LM358's footprint and pinout but cannot run from the LM358's 3 to 32 V supply range.

What has to match

Part type	Must match	Same or better is fine
MOSFET	package, channel type, pinout	V_DS, drain current, R_DS(on) at your gate voltage, lower V_GS(th)
Schottky diode	package, configuration	reverse voltage, current, lower forward voltage
Resistor, capacitor	value, package, dielectric	tolerance, voltage, power
Op-amp, timer, logic	package, pinout, supply range	everything else needs the datasheet

One trap: R_DS(on) is quoted at different gate voltages. A MOSFET listed at 35 mΩ at 10 V may be worse than one at 48 mΩ at 2.5 V if your gate is driven from a 3.3 V microcontroller pin. Compare at the voltage you actually drive it with.

AO3400A N-channel MOSFET (SOT-23)

The Alpha & Omega AO3400A (30 V, 5.7 A, 48 mΩ at 2.5 V) is a JLCPCB basic part at $0.0776 at 100 pieces, with 1.26 million in stock. A search for SOT-23 equivalents checked 400 candidates and found:

Part	Key specs	Price at 100	JLCPCB fee	Match
`HL3400` (hongjiacheng)	30 V, 5.6 A, 33 mΩ at 2.5 V	$0.0422	none (preferred)	every rule checked
`AO3400` (FOSAN)	30 V, 5.8 A, 25 mΩ at 4.5 V	$0.0174	$3	R_DS(on) at 2.5 V not listed
`AO3400` (GOODWORK)	30 V, 5.8 A, 28 mΩ at 10 V	$0.0305	$3	R_DS(on) at 2.5 V not listed
`AO3400C` (Alpha & Omega)	30 V, 6.2 A, 20 mΩ at 4.5 V	$0.0892	$3	R_DS(on) at 2.5 V not listed

The HL3400 is the only one whose datasheet values could all be compared at the same gate voltage, and it is a no-fee part, so for a JLCPCB board it is the easy swap: $4.22 instead of $7.76 for 100 boards. The FOSAN part is cheaper per piece, but with the $3 fee it only wins above about 120 boards, and its 2.5 V figure has to come from the datasheet.

SS34 Schottky diode (SMA)

The MDD SS34 (40 V, 3 A, 550 mV) is a basic part at $0.035 with 3.7 million in stock. All five equivalents found passed every check:

SS54 (MDD): 5 A instead of 3 A, $0.0363, basic. More headroom for almost the same price.
SS34 (hongjiacheng): same specs, $0.0355, preferred.
SL34 (MDD): 450 mV forward voltage instead of 550 mV, $0.0597, extended. Worth it where the diode drop matters, such as reverse polarity protection on a battery input.
B340A (MDD): same specs under another name, $0.0352, extended.

LM358 dual op-amp (SOIC-8)

The TI LM358DR was $0.0537 at JLCPCB as an extended part. Op-amps have no automatic comparison rules in our tool yet, so the search returned similar SOIC-8 dual op-amps and marked them as unchecked. Reading the specs:

LM358DR2G (onsemi): the same LM358 from another manufacturer, $0.0427 and a basic part with 663,580 in stock. This is the real equivalent. Its listed CMRR is 70 dB against TI's 99 dB, which rarely matters in the circuits LM358s are used in.
LM2904DR2G (onsemi): the automotive-temperature version of the same design, −40 to 105 °C, $0.0534, preferred. A fine drop-in.
MCP6002T-I/SN (Microchip): same pinout, but a 1.8 to 6 V supply. On a 12 V rail it would be destroyed. Not an equivalent.
NE5532DR (TI): same pinout, but 16 mA quiescent current and made for split-supply audio. Not an equivalent for a single-supply LM358 circuit.

NE555 timer (SOIC-8)

The TI NE555DR was $0.0841, a preferred part. The candidates split into two groups:

Bipolar 555s, true equivalents: NE555G-S08-R (UTC, 4.5 to 16 V, 200 mA output, $0.0738) and NA555DR (TI, the same chip rated −40 to 105 °C, $0.1797).
CMOS 555s, different parts: TLC555CDR and LMC555CMX run from 2 or 1.5 V and draw far less current, but their output only sources 100 mA instead of 200 mA. A better choice for a battery-powered board, a risk if the 555 drives a relay or a buzzer directly.

A process that works for any part

Search for the same part number from other manufacturers first. It is usually a true equivalent and often much cheaper.
Keep the package, then filter by the specs that must match for that part type.
Compare ratings at the conditions in your circuit, not the headline numbers.
For ICs, check the pinout and the supply range in the datasheet before anything else.
If JLCPCB assembles the board, prefer basic and preferred parts: an equivalent that saves $0.01 per piece but adds a $3 fee only pays off above 300 boards.

Prices and stock are JLCPCB/LCSC figures from 22 October 2026. If you search from an AI assistant with Next Everything, find_alternatives runs steps 2 and 3 for discretes and passives and shows the comparison for each candidate; for ICs it returns similar parts marked as unchecked, as above. More cases, including obsolete parts, are in how to replace an obsolete or out-of-stock part.

About the data

The numbers in this article come from Next Everything, an MCP server we build that lets AI assistants such as Claude, Cursor and Codex check a BOM against the JLCPCB/LCSC catalog and live Mouser and DigiKey prices. If you want to run the same check on your own BOM, the setup guides show how to connect it.

Next Everything is not affiliated with Mouser, DigiKey, JLCPCB or LCSC. Prices are list prices in USD at the time stated and change daily.