SF33-AP General Purpose Rectifier Diode Equivalent & Substitute Parts

Part Overview

The SF33-AP is a general purpose rectifier diode manufactured by Micro Commercial Co, rated for 150V DC reverse voltage and 3A average rectified current in a DO-201AD axial through-hole package. This component is classified as obsolete, which necessitates identification of active equivalent alternatives to maintain design continuity and ensure supply chain availability for new production and repair applications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	150	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	950 mV @ 3 A	mV
Reverse Recovery Time (trr)	35	ns
Current - Reverse Leakage @ Vr	5	µA @ 150 V
Package / Case	DO-201AD, Axial	—
Mounting Type	Through Hole	—
Technology	Standard	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SF33-AP is determined by electrical and mechanical parameter equivalence within the general purpose rectifier diode category. The critical parameters that define substitution eligibility are:

Voltage Rating: DC reverse voltage (Vr) must equal or exceed 150V
Current Rating: Average rectified current (Io) must equal or exceed 3A
Forward Voltage Drop: Maximum forward voltage (Vf) at rated current must not exceed 950 mV @ 3A
Recovery Characteristics: Reverse recovery time (trr) must not exceed 35 ns for fast recovery operation
Reverse Leakage: Maximum reverse leakage current must not exceed 5 µA @ 150V
Package Compatibility: DO-201AD axial through-hole package required for mechanical and thermal compatibility
Compliance: ROHS3 compliance required for regulatory alignment

The SF33G-AP qualifies as a direct substitute based on matching all critical electrical parameters and package specifications while offering active product status and extended operating temperature range.

Parameter Comparison

Parameter	SF33-AP (Main Part)	SF33G-AP (Substitute)	Match Status
Manufacturer	Micro Commercial Co	Micro Commercial Co	Identical
Voltage - DC Reverse (Vr) (Max)	150 V	150 V	Identical
Current - Average Rectified (Io)	3 A	3 A	Identical
Voltage - Forward (Vf) (Max) @ If	950 mV @ 3 A	950 mV @ 3 A	Identical
Reverse Recovery Time (trr)	35 ns	35 ns	Identical
Current - Reverse Leakage @ Vr	5 µA @ 150 V	5 µA @ 150 V	Identical
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Identical
Package / Case	DO-201AD, Axial	DO-201AD, Axial	Identical
Mounting Type	Through Hole	Through Hole	Identical
Operating Temperature - Junction	-55°C ~ 125°C	-65°C ~ 150°C	Substitute Exceeds
Capacitance @ Vr, F	100 pF @ 4V, 1MHz	50 pF @ 4V, 1MHz	Substitute Lower
Product Status	Obsolete	Active	Substitute Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Identical

Engineering Selection Recommendations

The SF33G-AP is a direct functional equivalent to the SF33-AP and is the appropriate selection for new designs and production applications. The SF33G-AP maintains identical electrical performance across all critical rectification parameters while offering the following advantages:

Product Status: The SF33G-AP carries active product status, ensuring continued availability and manufacturing support, whereas the SF33-AP is obsolete and subject to supply discontinuation.

Compliance: Both parts maintain ROHS3 compliance and identical moisture sensitivity ratings, ensuring regulatory alignment and handling consistency.

Operating Range: The SF33G-AP provides an extended junction temperature operating range (-65°C to 150°C) compared to the SF33-AP (-55°C to 125°C), offering improved thermal margin for demanding applications.

Capacitance Characteristic: The SF33G-AP exhibits lower junction capacitance (50 pF versus 100 pF at 4V, 1MHz), which may provide improved high-frequency switching performance in certain circuit topologies.

Mechanical Compatibility: Both parts utilize identical DO-201AD axial through-hole packaging, ensuring direct mechanical and thermal compatibility in existing PCB layouts without modification.

Frequently Asked Questions (FAQ)

Q: Can the SF33G-AP be used as a direct replacement for the SF33-AP in existing designs?

A: Yes. The SF33G-AP is electrically and mechanically equivalent to the SF33-AP. All critical rectification parameters—voltage rating, current rating, forward voltage drop, and recovery time—are identical. The DO-201AD axial through-hole package is identical, requiring no PCB layout modifications.

Q: What is the primary reason to transition from SF33-AP to SF33G-AP?

A: The SF33-AP is classified as obsolete, which creates supply chain risk. The SF33G-AP is an active product with confirmed manufacturing support and inventory availability, ensuring long-term design continuity.

Q: Are there any electrical performance differences between these parts?

A: The core rectification parameters are identical. The SF33G-AP exhibits lower junction capacitance (50 pF versus 100 pF), which may improve performance in high-frequency switching applications. The SF33G-AP also provides an extended operating temperature range, offering additional thermal margin.

Q: Do both parts require the same handling and storage procedures?

A: Yes. Both parts carry identical Moisture Sensitivity Level (MSL) ratings of 1 (Unlimited), indicating no special moisture control requirements during storage or handling.

Q: Is the DO-201AD package suitable for automated assembly?

A: The DO-201AD is an axial through-hole package designed for manual or wave soldering processes. Both the SF33-AP and SF33G-AP use this package format and are compatible with standard through-hole assembly equipment and procedures.

Q: What compliance certifications apply to the SF33G-AP?

A: The SF33G-AP is ROHS3 compliant and carries REACH Unaffected status, meeting current environmental and regulatory requirements for electronic component manufacturing and distribution.

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