BYT03-400RL Equivalent & Substitute Parts

Part Overview

The BYT03-400RL is a general-purpose rectifier diode manufactured by STMicroelectronics, rated for 400 V DC reverse voltage and 3 A average rectified current in a DO-201AD axial through-hole package. This component is classified as obsolete, indicating it has been discontinued and is no longer recommended for new designs. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support legacy system maintenance and repairs.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 3 A	V
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	55	ns
Current - Reverse Leakage @ Vr	20	µA @ 400 V
Mounting Type	Through Hole	—
Package / Case	DO-201AD, Axial	—
Operating Temperature - Junction (Max)	150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the BYT03-400RL is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 400 V
Current - Average Rectified (Io): Must equal or exceed 3 A
Mounting Type: Through Hole
Package / Case: DO-201AD or compatible axial package

Secondary Compatibility Factors:

Forward voltage (Vf) at rated current
Reverse recovery time (trr) and speed classification
Reverse leakage current
Operating temperature range
RoHS and REACH compliance status

Parts are grouped into two categories:

Direct Equivalents: Parts with identical electrical ratings (400 V, 3 A), same package (DO-201AD), and active product status. These provide pin-for-pin and functional replacement.

Functional Substitutes: Parts meeting or exceeding the core electrical requirements (400 V, 3 A) but with different package configurations (DO-15) or alternative manufacturers. These require mechanical board layout verification but maintain electrical compatibility.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V]	Speed	trr [ns]	Ir @ Vr [µA]	Package	Tj (Max) [°C]	Product Status
BYT03-400RL	STMicroelectronics	400	3	1.5 @ 3 A	Fast Recovery ≤ 500ns	55	20 @ 400 V	DO-201AD	150	Obsolete
STTH3R04RL	STMicroelectronics	400	3	1.5 @ 3 A	Fast Recovery ≤ 500ns	35	5 @ 400 V	DO-201AD	175	Active
STTH3R04QRL	STMicroelectronics	400	3	1.5 @ 3 A	Fast Recovery ≤ 500ns	35	5 @ 400 V	DO-15	175	Active
1N5404-E3/54	Vishay General Semiconductor	400	3	1.2 @ 3 A	Standard Recovery >500ns	—	5 @ 400 V	DO-201AD	150	Active
1N5404-G	Comchip Technology	400	3	0.95 @ 3 A	Standard Recovery >500ns	—	5 @ 400 V	DO-201AD	125	Active
1N5404RLG	onsemi	400	3	1.0 @ 3 A	Standard Recovery >500ns	—	10 @ 400 V	DO-201AA / DO-27	150	Not For New Designs
1N5404GP-AP	Micro Commercial Co	400	3	1.1 @ 3 A	Standard Recovery >500ns	—	5 @ 400 V	DO-201AD	150	Active

Engineering Selection Recommendations

For Direct Replacement (Preferred):

STTH3R04RL is the primary recommended substitute. This STMicroelectronics part maintains identical electrical ratings (400 V, 3 A) and package configuration (DO-201AD) as the BYT03-400RL. The STTH3R04RL offers improved performance characteristics including reduced reverse recovery time (35 ns versus 55 ns), lower reverse leakage current (5 µA versus 20 µA), and higher maximum junction temperature (175°C versus 150°C). The part is in active production status and carries ROHS3 compliance.

For Package-Variant Replacement:

STTH3R04QRL provides equivalent electrical performance in a DO-15 package. This substitution requires verification of printed circuit board layout compatibility due to the different package footprint. The DO-15 package is smaller than DO-201AD, which may necessitate board redesign. This part is active and ROHS3 compliant.

For Alternative Manufacturers (Same Package):

1N5404-E3/54 (Vishay), 1N5404-G (Comchip), and 1N5404GP-AP (Micro Commercial Co) all meet the 400 V, 3 A electrical requirements in DO-201AD packages. These parts are in active production. The 1N5404 series uses standard recovery technology (>500ns) rather than fast recovery, which may affect switching performance in high-frequency applications. All three alternatives are ROHS3 compliant.

Not Recommended for New Designs:

1N5404RLG (onsemi) is designated "Not For New Designs" and should be avoided for new applications, though it remains available for legacy system support.

Compliance Verification:

All recommended substitutes maintain ROHS3 compliance and REACH unaffected status, matching the original BYT03-400RL specifications.

Frequently Asked Questions (FAQ)

Q: Can STTH3R04RL directly replace BYT03-400RL without board modifications?

A: Yes. STTH3R04RL is a direct pin-for-pin replacement with identical DO-201AD package configuration. No board layout changes are required. The improved electrical characteristics (lower reverse recovery time and leakage current) are compatible with existing circuit designs.

Q: What is the difference between fast recovery and standard recovery diodes in the substitute list?

A: The BYT03-400RL and STTH3R04RL are fast recovery diodes with reverse recovery time ≤ 500 ns. The 1N5404 series variants are standard recovery diodes with reverse recovery time > 500 ns. Fast recovery diodes switch more quickly, reducing switching losses in high-frequency applications. Standard recovery diodes are suitable for lower-frequency rectification circuits. Circuit performance requirements determine which technology is appropriate.

Q: Can I use STTH3R04QRL (DO-15 package) instead of the DO-201AD package?

A: STTH3R04QRL provides equivalent electrical performance but requires board layout verification. The DO-15 package is physically smaller than DO-201AD. If the original design uses DO-201AD footprints, the DO-15 package will not fit without board modification. Consult the PCB layout and component placement documentation before substituting.

Q: Are all substitute parts RoHS compliant?

A: Yes. All recommended substitute parts listed carry ROHS3 compliance certification, matching the original BYT03-400RL specification.

Q: What does "Not For New Designs" mean for the 1N5404RLG?

A: This designation indicates the manufacturer has discontinued active development and recommends against using this part in new circuit designs. The 1N5404RLG remains available for legacy system repairs and maintenance but should not be selected for new applications. Use STTH3R04RL or alternative active-status parts for new designs.

Q: How do forward voltage differences affect circuit performance?

A: Forward voltage (Vf) differences between substitutes range from 0.95 V to 1.5 V at 3 A. In rectifier circuits, this affects voltage drop across the diode and power dissipation. Lower forward voltage reduces heat generation. For most general-purpose rectification applications, these variations are acceptable. High-efficiency or thermally constrained designs should verify that the selected substitute's forward voltage meets power budget requirements.

Q: Can I substitute a 2 A diode (such as EGP20G) for the 3 A requirement?

A: No. EGP20G is rated for 2 A maximum average rectified current, which is below the 3 A requirement of the BYT03-400RL. Using an undersized diode creates thermal stress and reduces component reliability. Always select substitutes rated for equal or greater current capacity.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message