STTH3R04Q Equivalent & Substitute Parts

Part Overview

The STTH3R04Q 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-15 through-hole axial package. This component is classified as obsolete, indicating discontinuation from active production. Identification of equivalent and substitute parts is necessary to support ongoing maintenance, repair, and legacy system support where this diode remains in service or where design modifications require component replacement.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	400 V
Current - Average Rectified (Io)	3 A
Voltage - Forward (Vf) (Max) @ If	1.5 V @ 3 A
Speed Classification	Fast Recovery ≤ 500 ns, > 200 mA (Io)
Reverse Recovery Time (trr)	35 ns
Current - Reverse Leakage @ Vr	5 µA @ 400 V
Mounting Type	Through Hole
Package / Case	DO-204AC, DO-15, Axial
Operating Temperature - Junction (Max)	175°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the STTH3R04Q is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Requirements:

Voltage - DC Reverse (Vr) (Max): 400 V minimum
Current - Average Rectified (Io): 3 A minimum
Forward voltage (Vf) characteristics within acceptable operating range
Reverse leakage current at rated voltage

Mechanical Compatibility Requirements:

Mounting Type: Through Hole (axial configuration)
Package / Case: DO-15, DO-201AD, or equivalent axial packages
Physical form factor compatible with existing PCB layouts

Compliance Requirements:

RoHS3 Compliant status
REACH Unaffected status

Substitute parts are grouped into two categories based on recovery speed characteristics:

Category 1: Fast Recovery Diodes (≤ 500 ns) Parts with fast recovery characteristics matching or exceeding the STTH3R04Q performance envelope. These include STTH3R04QRL, EGP30G, FR304GP-AP, and FR304GP-TP.

Category 2: Standard Recovery Diodes (> 500 ns) Parts with standard recovery characteristics that meet the 400 V / 3 A electrical requirements but with different transient response. These include 1N5404-E3/54, 1N5404-G, 1N5404G, 1N5404GP-AP, 1N5404RLG, and GI504-E3/54.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf @ If	Speed	trr (ns)	Ir @ Vr	Package	Product Status
STTH3R04Q	STMicroelectronics	400 V	3 A	1.5 V @ 3 A	Fast Recovery ≤ 500 ns	35	5 µA @ 400 V	DO-15	Obsolete
STTH3R04QRL	STMicroelectronics	400 V	3 A	1.5 V @ 3 A	Fast Recovery ≤ 500 ns	35	5 µA @ 400 V	DO-15	Active
1N5404-E3/54	Vishay General Semiconductor	400 V	3 A	1.2 V @ 3 A	Standard Recovery > 500 ns	—	5 µA @ 400 V	DO-201AD	Active
1N5404-G	Comchip Technology	400 V	3 A	950 mV @ 3 A	Standard Recovery > 500 ns	—	5 µA @ 400 V	DO-27 (DO-201AD)	Active
1N5404G	onsemi	400 V	3 A	1 V @ 3 A	Standard Recovery > 500 ns	—	10 µA @ 400 V	DO-27	Not For New Designs
1N5404GP-AP	Micro Commercial Co	400 V	3 A	1.1 V @ 3 A	Standard Recovery > 500 ns	—	5 µA @ 400 V	DO-201AD	Active
1N5404RLG	onsemi	400 V	3 A	1 V @ 3 A	Standard Recovery > 500 ns	—	10 µA @ 400 V	DO-27	Not For New Designs
EGP30G	onsemi	400 V	3 A	1.25 V @ 3 A	Fast Recovery ≤ 500 ns	50	5 µA @ 400 V	DO-201AD	Not For New Designs
FR304GP-AP	Micro Commercial Co	400 V	3 A	1.3 V @ 3 A	Fast Recovery ≤ 500 ns	150	5 µA @ 400 V	DO-201AD	Active
FR304GP-TP	Micro Commercial Co	400 V	3 A	1.3 V @ 3 A	Fast Recovery ≤ 500 ns	150	5 µA @ 400 V	DO-201AD	Active
GI504-E3/54	Vishay General Semiconductor	400 V	3 A	1.1 V @ 9.4 A	Standard Recovery > 500 ns	2000	5 µA @ 400 V	DO-201AD	Active

Engineering Selection Recommendations

Primary Recommendation: STTH3R04QRL

The STTH3R04QRL is the direct equivalent to the obsolete STTH3R04Q, manufactured by the same supplier (STMicroelectronics) with identical electrical specifications and fast recovery characteristics. This part is in active production status with substantial inventory availability (9382 pcs), ensuring supply continuity. The only difference is packaging format (Cut Tape vs. unspecified for the original), which does not affect electrical performance. RoHS3 compliance and REACH unaffected status are maintained.

Secondary Recommendations for Fast Recovery Applications:

FR304GP-AP and FR304GP-TP (Micro Commercial Co) provide fast recovery performance (150 ns trr) with active product status. These parts are suitable for applications requiring fast switching characteristics. FR304GP-TP is supplied in Tape & Reel format for automated assembly.

EGP30G (onsemi) offers fast recovery characteristics (50 ns trr) but carries "Not For New Designs" status, limiting its use to legacy system support only.

Alternative Recommendations for Standard Recovery Applications:

1N5404-E3/54 (Vishay General Semiconductor) and 1N5404GP-AP (Micro Commercial Co) are active production parts meeting the 400 V / 3 A requirements with standard recovery characteristics. These are suitable for applications where switching speed is not critical. Forward voltage is lower than the STTH3R04Q (1.2 V and 1.1 V respectively vs. 1.5 V), which may reduce power dissipation in some circuit topologies.

1N5404-G (Comchip Technology) provides the lowest forward voltage (950 mV @ 3 A) among standard recovery options, offering potential efficiency improvements in high-current applications.

Parts to Avoid for New Designs:

1N5404G and 1N5404RLG (onsemi) carry "Not For New Designs" status and should be used only for legacy system maintenance where no alternative exists.

Frequently Asked Questions (FAQ)

Q: Can I use a standard recovery diode (1N5404 series) as a direct replacement for the STTH3R04Q?

A: Electrical substitution is possible because both fast and standard recovery diodes meet the 400 V / 3 A ratings and reverse leakage specifications. However, circuit performance may differ. Fast recovery diodes (STTH3R04Q, FR304GP series) have shorter reverse recovery times (35–150 ns), reducing switching losses and EMI in high-frequency applications. Standard recovery diodes (1N5404 series) have longer recovery times (>500 ns to 2 µs), which may cause increased switching losses and higher EMI. Application-specific circuit analysis is required to determine if standard recovery performance is acceptable.

Q: What is the difference between DO-15 and DO-201AD packages?

A: Both are through-hole axial packages for rectifier diodes. DO-15 (DO-204AC) and DO-201AD (DO-27) are physically similar but have different standardized dimensions. The STTH3R04Q uses DO-15 packaging. Substitute parts using DO-201AD packaging are mechanically compatible with existing through-hole PCB layouts designed for axial diodes, though lead spacing and body diameter may vary slightly. Physical verification against PCB artwork is recommended for space-constrained applications.

Q: Why does the STTH3R04Q show as obsolete when STTH3R04QRL is available?

A: The STTH3R04Q (without the "RL" suffix) has been discontinued by STMicroelectronics. The STTH3R04QRL is the active production equivalent with identical electrical specifications. The "RL" suffix indicates a packaging or reel format change. For new designs and ongoing procurement, the STTH3R04QRL should be specified.

Q: Are all listed substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed in this document carry RoHS3 Compliant status and REACH Unaffected designation, meeting current environmental and regulatory requirements.

Q: What is the significance of reverse recovery time (trr) in selecting a substitute?

A: Reverse recovery time determines how quickly the diode transitions from conducting to blocking state when reverse voltage is applied. Fast recovery diodes (trr ≤ 500 ns) are required in high-frequency switching applications, power factor correction circuits, and switch-mode power supplies to minimize switching losses and EMI. Standard recovery diodes (trr > 500 ns) are suitable for low-frequency rectification, power supply filtering, and applications where switching speed is not performance-critical. The STTH3R04Q's 35 ns trr indicates fast recovery performance; substitutes should maintain this characteristic for equivalent circuit behavior.

Q: Can I substitute a 1N5404 series diode in a circuit designed for the STTH3R04Q?

A: Electrical compatibility exists for the 400 V / 3 A ratings. However, circuit performance depends on application context. In low-frequency rectification (50/60 Hz), standard recovery 1N5404 diodes function identically. In switching power supplies, inverters, or high-frequency circuits, the longer recovery time of 1N5404 diodes may cause increased switching losses, higher junction temperatures, and increased EMI compared to the fast recovery STTH3R04Q. Circuit simulation or bench testing is necessary to confirm acceptable performance before production implementation.

Q: What inventory considerations should I account for when selecting a substitute?

A: Inventory availability varies significantly among substitute parts. STTH3R04QRL has the highest availability (9382 pcs), followed by 1N5404-G (208,868 pcs) and 1N5404RLG (16,846 pcs). Parts with lower inventory (FR304GP-AP: 720 pcs, 1N5404GP-AP: 1066 pcs) may have longer lead times or supply constraints. For high-volume production, parts with substantial inventory provide supply security. For legacy system support with lower volume requirements, any listed part with active status is suitable.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message