Equivalent & Substitute Parts for 10BQ040

Part Overview

The Vishay 10BQ040 is a Schottky rectifier diode rated for 40 V DC reverse voltage and 1 A average rectified current in a DO-214AA (SMB) surface mount package. This part is classified as obsolete, which necessitates identification of active equivalent and substitute components for new designs and ongoing production requirements. The 10BQ040 operates across a junction temperature range of -55°C to 150°C and is RoHS non-compliant. Active alternatives with equivalent or superior electrical characteristics are available from multiple manufacturers.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	40	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	530 mV @ 1 A	mV
Current - Reverse Leakage @ Vr	100	µA @ 40 V
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	ns
Technology	Schottky	—
Mounting Type	Surface Mount	—
Package / Case	DO-214AA, SMB	—
Operating Temperature - Junction	-55 to 150	°C

Substitute Part Grouping Explanation

Substitution of the 10BQ040 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 40 V
Current - Average Rectified (Io): Must equal or exceed 1 A
Technology: Schottky rectifier diode
Mounting Type: Surface Mount
Package / Case: DO-214AA (SMB) or compatible SMB variant
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)

Secondary Compatibility Factors:

Operating Temperature Range: Minimum -55°C to maximum 150°C or broader
Forward Voltage (Vf): Acceptable range 450 mV to 700 mV @ rated current
Reverse Leakage Current: Acceptable range 12 µA to 1 mA @ 40 V

Substitute parts are grouped into two categories:

Category A - Direct Equivalents (40 V, 1 A): Parts meeting all primary criteria with identical voltage and current ratings. These include VS-10BQ040-M3/5BT, B140B-13-F, B140HB-13-F, MBRS140T3G, and STPS140U.

Category B - Higher Current Capability (40 V, ≥ 2 A): Parts exceeding the 1 A current requirement while maintaining 40 V voltage rating. These include SK24-AU_R1_000A1 (2 A), SK34B-LTP (3 A), and SK44BL-TP (4 A). These parts are electrically compatible for applications where higher current capacity provides design margin or future scalability.

Category C - Higher Voltage Rating (≥ 50 V, 1 A): Part B150B-13-F rated for 50 V, 1 A. This part is compatible for applications requiring higher voltage margin but is not recommended as a direct replacement due to increased forward voltage drop (700 mV @ 1 A).

Category D - Incompatible Parts: RB051L-40TE25 (20 V, 3 A) does not meet the 40 V minimum voltage requirement and is excluded from substitution consideration.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [mV]	Ir @ Vr [µA]	Product Status	RoHS Status	Operating Temp [°C]
10BQ040	Vishay	40	1	530 @ 1A	100 @ 40V	Obsolete	Non-compliant	-55 to 150
VS-10BQ040-M3/5BT	Vishay	40	1	450 @ 1A	100 @ 40V	Active	ROHS3 Compliant	-55 to 150
B140B-13-F	Diodes Inc.	40	1	500 @ 1A	500 @ 40V	Active	ROHS3 Compliant	-65 to 150
B140HB-13-F	Diodes Inc.	40	1	530 @ 1A	100 @ 40V	Active	ROHS3 Compliant	-55 to 150
B150B-13-F	Diodes Inc.	50	1	700 @ 1A	500 @ 50V	Active	ROHS3 Compliant	-65 to 150
MBRS140T3G	onsemi	40	1	600 @ 1A	1000 @ 40V	Active	ROHS3 Compliant	-65 to 125
SK24-AU_R1_000A1	Panjit	40	2	500 @ 2A	90 @ 40V	Active	ROHS3 Compliant	-55 to 150
SK34B-LTP	Micro Commercial	40	3	500 @ 3A	500 @ 40V	Active	ROHS3 Compliant	-55 to 150
SK44BL-TP	Micro Commercial	40	4	450 @ 4A	500 @ 40V	Active	ROHS3 Compliant	-55 to 150
STPS140U	STMicroelectronics	40	1	550 @ 1A	12 @ 40V	Active	ROHS3 Compliant	-55 to 150

Engineering Selection Recommendations

Primary Recommendation for Direct Replacement:

VS-10BQ040-M3/5BT (Vishay) is the preferred direct substitute. This part maintains identical voltage and current ratings (40 V, 1 A), operates across the same temperature range (-55°C to 150°C), and offers improved forward voltage performance (450 mV vs. 530 mV @ 1 A). The part is ROHS3 compliant and carries active product status with substantial inventory availability (61,143 units).

Alternative Direct Equivalents:

B140HB-13-F (Diodes Incorporated) provides electrical equivalence with identical forward voltage (530 mV @ 1 A) and reverse leakage (100 µA @ 40 V) characteristics. This part is ROHS3 compliant and active. Operating temperature range extends to -55°C to 150°C, matching the original specification.

STPS140U (STMicroelectronics) offers superior reverse leakage performance (12 µA @ 40 V) compared to the original 10BQ040 (100 µA @ 40 V). Forward voltage is 550 mV @ 1 A. This part is ROHS3 compliant and active with adequate inventory (16,100 units).

Higher Current Alternatives (40 V Rating):

SK24-AU_R1_000A1 (Panjit, 2 A), SK34B-LTP (Micro Commercial, 3 A), and SK44BL-TP (Micro Commercial, 4 A) are electrically compatible for applications requiring current capacity beyond 1 A. All three maintain 40 V voltage rating, ROHS3 compliance, and active product status. These parts are suitable for designs where increased current margin is beneficial.

Not Recommended:

B150B-13-F (50 V, 1 A) exhibits significantly higher forward voltage (700 mV @ 1 A) and elevated reverse leakage (500 µA @ 50 V). This part introduces unnecessary power dissipation and is not recommended as a direct replacement.

MBRS140T3G (onsemi) exhibits elevated reverse leakage (1 mA @ 40 V) and reduced maximum operating temperature (125°C vs. 150°C). This part is not recommended for applications requiring the full -55°C to 150°C temperature range.

Frequently Asked Questions (FAQ)

Q: Can the VS-10BQ040-M3/5BT directly replace the obsolete 10BQ040 without circuit modification?

A: Yes. The VS-10BQ040-M3/5BT maintains identical voltage (40 V) and current (1 A) ratings, operates across the same temperature range (-55°C to 150°C), and is housed in the same DO-214AA (SMB) package. The improved forward voltage (450 mV vs. 530 mV @ 1 A) reduces power dissipation. No circuit modification is required.

Q: What is the difference between the substitute parts in terms of forward voltage drop?

A: Forward voltage varies across the substitute parts. VS-10BQ040-M3/5BT exhibits the lowest drop at 450 mV @ 1 A. B140B-13-F and SK24-AU_R1_000A1 are rated at 500 mV. B140HB-13-F and STPS140U are rated at 530 mV and 550 mV respectively. MBRS140T3G is rated at 600 mV. B150B-13-F exhibits the highest drop at 700 mV @ 1 A. Lower forward voltage reduces power dissipation and heat generation in the circuit.

Q: Are all substitute parts RoHS compliant?

A: The original 10BQ040 is RoHS non-compliant. All recommended substitute parts (VS-10BQ040-M3/5BT, B140B-13-F, B140HB-13-F, B150B-13-F, MBRS140T3G, SK24-AU_R1_000A1, SK34B-LTP, SK44BL-TP, and STPS140U) are ROHS3 compliant, meeting current regulatory requirements.

Q: Can I use a higher current rated part such as SK34B-LTP (3 A) in place of the 1 A rated 10BQ040?

A: Yes. SK34B-LTP maintains the 40 V voltage rating and is electrically compatible. The higher current rating (3 A vs. 1 A) provides design margin and does not create incompatibility. The part operates across the same temperature range (-55°C to 150°C) and is housed in the same DO-214AA (SMB) package. This substitution is suitable for applications where increased current capacity is beneficial or where future design scaling is anticipated.

Q: What is the significance of reverse leakage current differences among the substitute parts?

A: Reverse leakage current ranges from 12 µA (STPS140U) to 1 mA (MBRS140T3G) across the substitute parts. Lower reverse leakage reduces standby power consumption and heat generation. The original 10BQ040 specifies 100 µA @ 40 V. STPS140U offers superior performance at 12 µA. Parts with higher leakage (500 µA to 1 mA) are acceptable for most applications but may increase power dissipation in high-impedance circuits.

Q: Are all substitute parts available in the same DO-214AA (SMB) package?

A: Yes. All recommended substitute parts are housed in the DO-214AA (SMB) surface mount package, ensuring mechanical and footprint compatibility with the original 10BQ040. Package designation may vary slightly (SMB, HSMB, or PMDS) but all parts are compatible with standard DO-214AA PCB layouts.

Q: What is the operating temperature range difference between substitute parts?

A: The original 10BQ040 operates from -55°C to 150°C. Most substitute parts maintain this range. B140B-13-F and B150B-13-F extend the lower limit to -65°C. MBRS140T3G reduces the upper limit to 125°C. For applications requiring the full -55°C to 150°C range, VS-10BQ040-M3/5BT, B140HB-13-F, SK24-AU_R1_000A1, SK34B-LTP, SK44BL-TP, and STPS140U are suitable selections.

Q: Why is B150B-13-F (50 V) not recommended as a direct replacement?

A: While B150B-13-F maintains the 1 A current rating and is electrically compatible, the 50 V voltage rating exceeds the 40 V requirement of the original circuit. More significantly, the forward voltage is substantially higher at 700 mV @ 1 A compared to 530 mV for the 10BQ040. This increases power dissipation by approximately 32% and introduces unnecessary thermal stress. The part is suitable only for applications requiring higher voltage margin.

Q: What inventory status should I consider when selecting a substitute?

A: All recommended substitute parts carry active product status with substantial inventory availability. VS-10BQ040-M3/5BT offers the highest inventory (61,143 units), followed by SK34B-LTP (146,400 units) and MBRS140T3G (55,300 units). Parts with lower inventory such as B140HB-13-F (7,680 units) and SK24-AU_R1_000A1 (867 units) may require longer lead times. For production continuity, VS-10BQ040-M3/5BT or SK34B-LTP are preferred selections.

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