BAS45A,143 Equivalent & Substitute Parts

Part Overview

The BAS45A,143 is a general-purpose rectifier diode manufactured by Nexperia USA Inc., rated for 125 V DC reverse voltage and 250 mA average rectified current in a DO-34 axial through-hole package. This component is classified as Active product status and is ROHS3 compliant. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to inventory constraints, manufacturing discontinuation, or design flexibility needs.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	125	V
Current - Average Rectified (Io)	250	mA
Voltage - Forward (Vf) (Max) @ If	1 V @ 100 mA	V
Reverse Recovery Time (trr)	1.5	µs
Current - Reverse Leakage @ Vr	1	nA @ 125 V
Capacitance @ Vr, F	4	pF @ 0V, 1MHz
Package / Case	DO-204AG, DO-34, Axial	—
Mounting Type	Through Hole	—
Operating Temperature - Junction (Max)	175	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the BAS45A,143 are classified into two categories based on electrical and mechanical compatibility:

Parametric Equivalent (Direct Substitution): Parts that match all critical electrical parameters and package specifications. The BAS45A,133 from Nexperia USA Inc. is a parametric equivalent, sharing identical voltage rating (125 V), current rating (250 mA), forward voltage characteristics, recovery time, and DO-34 package configuration.

Similar Parts (Application-Dependent Substitution): Parts that maintain the same voltage rating (125 V) and through-hole mounting type but differ in current rating, package variant (DO-35 instead of DO-34), or recovery speed characteristics. These include BAY72TR, BAY73, FDH444, and FDH444TR. Substitution of these parts is valid when circuit design permits operation at the specified current rating and package footprint differences are accommodated.

Key Parameters Determining Substitution:

Voltage - DC Reverse (Vr) (Max): 125 V (mandatory match)
Mounting Type: Through Hole (mandatory match)
Current - Average Rectified (Io): 250 mA (parametric equivalent) or lower (similar parts acceptable if circuit design permits)
Package / Case: DO-34 (parametric equivalent) or DO-35 (similar parts with mechanical accommodation)
Operating Temperature - Junction: 175°C (all parts match)

Parameter Comparison

Parameter	BAS45A,143	BAS45A,133	BAY72TR	BAY73	FDH444	FDH444TR
Manufacturer	Nexperia USA Inc.	Nexperia USA Inc.	Fairchild Semiconductor	onsemi	Fairchild Semiconductor	Fairchild Semiconductor
Voltage - DC Reverse (Vr) (Max)	125 V	125 V	125 V	125 V	125 V	125 V
Current - Average Rectified (Io)	250 mA	250 mA	200 mA	500 mA	200 mA	200 mA
Voltage - Forward (Vf) (Max) @ If	1 V @ 100 mA	1 V @ 100 mA	1 V @ 100 mA	1 V @ 200 mA	1.2 V @ 300 mA	1.2 V @ 300 mA
Reverse Recovery Time (trr)	1.5 µs	1.5 µs	50 ns	1 µs	60 ns	60 ns
Current - Reverse Leakage @ Vr	1 nA @ 125 V	1 nA @ 125 V	100 nA @ 100 V	5 nA @ 100 V	50 nA @ 100 V	50 nA @ 100 V
Capacitance @ Vr, F	4 pF @ 0V, 1MHz	4 pF @ 0V, 1MHz	5 pF @ 0V, 1MHz	8 pF @ 0V, 1MHz	2.5 pF @ 0V, 1MHz	2.5 pF @ 0V, 1MHz
Package / Case	DO-204AG, DO-34, Axial	DO-204AG, DO-34, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Operating Temperature - Junction (Max)	175°C	175°C	175°C	175°C	175°C	175°C
Product Status	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Not Specified	ROHS3 Compliant	Not Specified	Not Specified

Engineering Selection Recommendations

BAS45A,133 (Parametric Equivalent): This part is the direct substitute for BAS45A,143. Both components are manufactured by Nexperia USA Inc., share identical electrical specifications, and are packaged in DO-34 axial configuration. Both are ROHS3 compliant and Active product status. Selection of BAS45A,133 requires no circuit redesign and maintains full compatibility with existing PCB layouts and component footprints.

BAY72TR (Similar Part - Current Derating): BAY72TR is manufactured by Fairchild Semiconductor with a reduced current rating of 200 mA compared to the 250 mA specification of BAS45A,143. This part operates at a lower average rectified current and features faster recovery time (50 ns versus 1.5 µs). Selection is valid for applications where circuit design permits operation at 200 mA or lower. Package variant is DO-35 (DO-204AH), requiring mechanical accommodation on the PCB. Product status is Active.

BAY73 (Similar Part - Current Upgrade): BAY73 is manufactured by onsemi with an elevated current rating of 500 mA, exceeding the 250 mA specification of BAS45A,143. This part is ROHS3 compliant and Active product status. The package variant is DO-35 (DO-204AH), requiring mechanical accommodation. Selection is valid for applications requiring higher current capacity or as a general-purpose upgrade. Recovery time is 1 µs, comparable to BAS45A,143.

FDH444 and FDH444TR (Similar Parts - Current Derating): Both FDH444 and FDH444TR are manufactured by Fairchild Semiconductor with identical specifications: 200 mA current rating, 125 V voltage rating, and DO-35 package. FDH444TR is the tape-reel variant of FDH444. These parts feature faster recovery time (60 ns) and lower capacitance (2.5 pF) compared to BAS45A,143. Selection is valid for applications where circuit design permits operation at 200 mA or lower. Package variant is DO-35 (DO-204AH), requiring mechanical accommodation on the PCB. Product status is Active for both variants.

Frequently Asked Questions (FAQ)

Q: Can BAS45A,133 be used as a direct replacement for BAS45A,143?

A: Yes. BAS45A,133 is a parametric equivalent with identical voltage rating (125 V), current rating (250 mA), forward voltage characteristics, recovery time (1.5 µs), and DO-34 package configuration. Both are manufactured by Nexperia USA Inc. and are ROHS3 compliant. No circuit redesign is required.

Q: What is the difference between DO-34 and DO-35 packages?

A: DO-34 and DO-35 are both axial through-hole diode packages with different physical dimensions. DO-34 (DO-204AG) is smaller than DO-35 (DO-204AH). When substituting a DO-34 part with a DO-35 part, the PCB footprint and lead spacing must be verified for mechanical compatibility. The electrical performance is not affected by package variant.

Q: Can BAY72TR replace BAS45A,143 in all applications?

A: BAY72TR has a reduced current rating of 200 mA compared to BAS45A,143 at 250 mA. Substitution is valid only when circuit design permits operation at 200 mA or lower. The package variant is DO-35 instead of DO-34, requiring mechanical accommodation. Verify circuit current requirements before selection.

Q: Why does BAY73 have a higher current rating than BAS45A,143?

A: BAY73 is rated for 500 mA average rectified current, which exceeds the 250 mA specification of BAS45A,143. This higher rating reflects different semiconductor design and thermal characteristics. BAY73 can be used in applications requiring higher current capacity or as a general-purpose upgrade when the DO-35 package is acceptable.

Q: Are FDH444 and FDH444TR electrically identical?

A: Yes. FDH444 and FDH444TR are electrically identical. FDH444TR is the tape-reel packaging variant of FDH444, suitable for automated assembly processes. Both have 200 mA current rating, 125 V voltage rating, and identical electrical characteristics. Selection between them depends on packaging and assembly requirements.

Q: What does "parametric equivalent" mean in this context?

A: A parametric equivalent part matches all critical electrical specifications and package configuration of the original part. For BAS45A,143, the parametric equivalent is BAS45A,133, which shares identical voltage rating, current rating, forward voltage, recovery time, and DO-34 package. Parametric equivalents require no circuit redesign.

Q: Can I use BAY73 in place of BAS45A,143 if my circuit only requires 250 mA?

A: Yes. BAY73 is rated for 500 mA, which exceeds the 250 mA requirement. Operating at 250 mA is within the part's specification. The package variant is DO-35 instead of DO-34, so mechanical accommodation on the PCB must be verified. BAY73 is ROHS3 compliant and Active product status.

Q: What is the significance of reverse recovery time in diode selection?

A: Reverse recovery time (trr) affects switching speed and switching losses in high-frequency applications. BAS45A,143 has trr of 1.5 µs (standard recovery), while FDH444 and BAY72TR have faster recovery times (60 ns and 50 ns respectively). For low-frequency rectification applications, recovery time differences are not critical. For high-frequency switching applications, faster recovery times reduce switching losses.

Q: Are all substitute parts ROHS3 compliant?

A: BAS45A,143, BAS45A,133, and BAY73 are explicitly ROHS3 compliant. FDH444, FDH444TR, and BAY72TR do not have RoHS status specified in the provided data. Verify RoHS compliance requirements with the manufacturer or supplier before final selection.

Q: What inventory levels are available for each part?

A: BAS45A,143 has 4,178 pieces in stock. BAS45A,133 has 10,460 pieces. BAY72TR has 80,843 pieces. BAY73 has 8,928 pieces. FDH444 has 26,955 pieces. FDH444TR has 40,970 pieces. Inventory levels are subject to change and should be confirmed with the supplier.

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