What L4 can be
L4BAT54Schottky diodeSOT-23 · Nexperia · 30 V · 200 mA
Pins: 1=A 2=n.c. 3=K
On the part, one more character can follow L4: a date or factory code. datasheet
L4BAT54WSchottky diodeSOT-323 · Nexperia · 30 V · 200 mA
Pins: 1=A 2=n.c. 3=K
On the part, one more character can follow L4: a date or factory code. datasheet
Package size
| Package | Also called | Body | Height |
|---|---|---|---|
| SOT-23 | TO-236AB, SOT-23-3 | 2.9 × 1.3 mm | 1 mm |
| SOT-323 | SC-70, SC-70-3 | 2 × 1.25 mm | 0.95 mm |
Nominal body size without the leads.
How to tell them apart
Measure the plastic body without the leads: SOT-23 2.9 × 1.3 mm · SOT-323 2 × 1.25 mm.
Look at where it sits: a small part next to a USB connector is often ESD protection or a Schottky diode; a 3- or 5-pin part near the power input is often a regulator.
The same code can mean different parts at different makers. The package narrows it down, so measure the body.
Open the SMD identifier →Not sure it is this part? Enter the marking with the shape and size of the body: the identifier checks it against all 340 markings in the database.
Related parts and their markings
| Part | Marking | Type | Package |
|---|---|---|---|
| BAT54 | L4P, JV3, KL1 | Schottky diode | SOT-23 |
| BAT54A | V3, L42, KL2 | Dual Schottky diode | SOT-23 |
| BAT54AW | 42 | Dual Schottky diode | SOT-323 |
| BAT54C | W1, L43, KL3 | Dual Schottky diode | SOT-23 |
| BAT54CW | 43 | Dual Schottky diode | SOT-323 |
| BAT54S | V4, L44, LD3, KL4 | Dual Schottky diode | SOT-23 |
| BAT54SW | 44 | Dual Schottky diode | SOT-323 |
| BAT54WS | L9 | Schottky diode | SOD-323 |
Codes that look similar
Easy to mix up with L4 when the print is worn or a character is cut off:
Frequently asked questions
What is the pinout of SMD code L4?
BAT54 (SOT-23): 1=A 2=n.c. 3=K. BAT54W (SOT-323): 1=A 2=n.c. 3=K.
Marking codes checked against the makers’ datasheets; each part links to its own.