BAS21THR Equivalent & Substitute Parts

Part Overview

The BAS21THR is a general-purpose rectifier diode manufactured by Nexperia USA Inc., rated for 200 V DC reverse voltage and 200 mA average rectified current in a surface mount TO-236AB package. This component is classified as a small-signal diode with automotive-grade qualification (AEC-Q101) and is actively produced. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and design continuity across manufacturing environments.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	200	V
Current - Average Rectified (Io)	200	mA
Voltage - Forward (Vf) (Max) @ If	1.25	V @ 200 mA
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	100	nA @ 200 V
Capacitance @ Vr, F	5	pF @ 0V, 1MHz
Operating Temperature - Junction (Max)	175	°C
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q101	—

Substitute Part Grouping Explanation

Substitution of the BAS21THR is determined by electrical and mechanical parameter alignment within the diode rectifier category. The following criteria establish substitution validity:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 200 V minimum
Current - Average Rectified (Io): 200 mA minimum
Package / Case: TO-236-3, SC-59, SOT-23-3 (surface mount compatibility)
Mounting Type: Surface Mount
Technology: Standard

Secondary Compliance Criteria:

RoHS3 Compliance
Moisture Sensitivity Level (MSL): 1 (Unlimited)
REACH Status: REACH Unaffected

Substitute parts are grouped into two categories: Parametric Equivalents (identical electrical specifications and single-diode configuration) and Similar Parts (matching voltage and current ratings with alternative internal configurations such as diode arrays).

Parameter Comparison

Parameter	BAS21THR	BAS21THVL	MMBD1504A
Manufacturer	Nexperia USA Inc.	Nexperia USA Inc.	onsemi
Voltage - DC Reverse (Vr) (Max)	200 V	200 V	200 V
Current - Average Rectified (Io)	200 mA	200 mA	200 mA (per Diode)
Voltage - Forward (Vf) (Max) @ If	1.25 V @ 200 mA	1.25 V @ 200 mA	1.1 V @ 200 mA
Reverse Recovery Time (trr)	50 ns	50 ns	Not specified
Current - Reverse Leakage @ Vr	100 nA @ 200 V	100 nA @ 200 V	10 nA @ 180 V
Operating Temperature - Junction (Max)	175°C	175°C	150°C
Package / Case	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3
Diode Configuration	Single Diode	Single Diode	1 Pair Common Cathode
Grade	Automotive	Automotive	Not specified
Qualification	AEC-Q101	AEC-Q101	Not specified
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

BAS21THVL (Parametric Equivalent): The BAS21THVL is a direct parametric equivalent to the BAS21THR. Both parts are manufactured by Nexperia USA Inc., share identical electrical specifications, and carry automotive-grade AEC-Q101 qualification. The BAS21THVL is suitable for direct substitution in applications requiring single-diode rectification at 200 V and 200 mA ratings. Both parts maintain ROHS3 compliance and unlimited moisture sensitivity classification.

MMBD1504A (Similar Part - Diode Array): The MMBD1504A is a diode array configuration (1 Pair Common Cathode) manufactured by onsemi. While it meets the 200 V reverse voltage and 200 mA per-diode current requirements, its internal configuration differs from the single-diode BAS21THR. The MMBD1504A exhibits lower forward voltage (1.1 V vs. 1.25 V) and superior reverse leakage characteristics (10 nA vs. 100 nA). However, the MMBD1504A does not carry automotive-grade certification or AEC-Q101 qualification, and its maximum junction temperature is 150°C compared to 175°C for the BAS21THR. Selection of MMBD1504A requires circuit-level evaluation to confirm compatibility with the common-cathode diode pair configuration and thermal operating conditions.

Frequently Asked Questions (FAQ)

Q: Can BAS21THVL be used as a direct replacement for BAS21THR?

A: Yes. The BAS21THVL is a parametric equivalent with identical voltage, current, and thermal specifications. Both parts are AEC-Q101 qualified and ROHS3 compliant. No circuit modifications are required for substitution.

Q: What is the key difference between BAS21THR and MMBD1504A?

A: The BAS21THR is a single-diode rectifier, while the MMBD1504A is a diode array with two diodes sharing a common cathode. This configuration difference affects circuit topology and pin assignment. Additionally, MMBD1504A lacks automotive-grade certification.

Q: Is MMBD1504A suitable for automotive applications?

A: The MMBD1504A is not qualified to AEC-Q101 automotive standards. While it meets the electrical voltage and current parameters, applications requiring automotive-grade components should use BAS21THR or BAS21THVL.

Q: Are all three parts available in the same package?

A: Yes. All three parts use the TO-236-3 (SC-59, SOT-23-3) surface mount package, ensuring mechanical and footprint compatibility on printed circuit boards.

Q: What are the thermal operating limits for each part?

A: BAS21THR and BAS21THVL both support maximum junction temperatures of 175°C. MMBD1504A is rated to 150°C maximum junction temperature, which may limit its use in high-temperature environments.

Q: Do all parts meet RoHS and REACH compliance requirements?

A: Yes. All three parts are ROHS3 compliant, REACH unaffected, and carry MSL 1 (Unlimited) moisture sensitivity classification.

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