STPS640CB Equivalent & Substitute Parts

Part Overview

The STPS640CB is a Schottky diode array manufactured by STMicroelectronics, configured as 1 pair common cathode with a maximum reverse voltage of 40 V and average rectified current of 3 A per diode. The device is packaged in TO-252-3 DPAK surface mount configuration. This part is classified as obsolete, making identification of equivalent and substitute components necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value
Diode Configuration	1 Pair Common Cathode
Technology	Schottky
Voltage - DC Reverse (Vr) (Max)	40 V
Current - Average Rectified (Io) (per Diode)	3 A
Voltage - Forward (Vf) (Max) @ If	630 mV @ 3 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	100 µA @ 40 V
Operating Temperature - Junction (Max)	150°C
Mounting Type	Surface Mount
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the STPS640CB is determined by the following critical parameters: diode configuration (1 pair common cathode), technology (Schottky), package type (TO-252-3 DPAK), reverse voltage rating, average rectified current per diode, and forward voltage characteristics. Substitute parts must maintain electrical compatibility within the application's voltage and current requirements while preserving the same physical package footprint for PCB compatibility.

The substitute parts identified are grouped into two categories:

Direct Electrical Equivalents: Parts that maintain identical or superior electrical specifications at the rated operating conditions, allowing drop-in replacement without circuit modification.

Higher Voltage Rated Alternatives: Parts with elevated reverse voltage ratings that provide enhanced voltage margin while maintaining current capacity and package compatibility.

Parameter Comparison

Parameter	STPS640CB (Main)	MBRD640CTT4G	MBRD650CTT4G	RB085BM-40TL
Manufacturer	STMicroelectronics	onsemi	onsemi	Rohm Semiconductor
Diode Configuration	1 Pair Common Cathode	1 Pair Common Cathode	1 Pair Common Cathode	Single Diode
Technology	Schottky	Schottky	Schottky	Schottky
Voltage - DC Reverse (Vr) (Max)	40 V	40 V	50 V	45 V
Current - Average Rectified (Io)	3 A	3 A	3 A	10 A
Voltage - Forward (Vf) (Max) @ If	630 mV @ 3 A	700 mV @ 3 A	700 mV @ 3 A	550 mV @ 5 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	100 µA @ 40 V	100 µA @ 40 V	100 µA @ 50 V	200 µA @ 40 V
Operating Temperature - Junction	150°C (Max)	-65°C ~ 175°C	-65°C ~ 175°C	150°C (Max)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK	TO-252-3, DPAK
Product Status	Obsolete	Active	Active	Not For New Designs
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

MBRD640CTT4G (onsemi): This part is the primary direct equivalent to the STPS640CB. It maintains identical diode configuration (1 pair common cathode), reverse voltage rating (40 V), and average rectified current (3 A per diode). The MBRD640CTT4G is classified as active product status with extended operating temperature range (-65°C to 175°C) compared to the STPS640CB maximum of 150°C. Forward voltage is specified at 700 mV @ 3 A, which is 70 mV higher than the STPS640CB. Both devices are ROHS3 compliant and packaged identically in TO-252-3 DPAK. This substitute is suitable for direct replacement in applications where the higher forward voltage drop is acceptable.

MBRD650CTT4G (onsemi): This part provides elevated reverse voltage rating of 50 V while maintaining the same diode configuration, current rating (3 A per diode), and package type. The MBRD650CTT4G is active product status with extended operating temperature range. This substitute is applicable in designs requiring additional voltage margin above the 40 V specification of the STPS640CB, provided the circuit topology accommodates the higher voltage rating.

RB085BM-40TL (Rohm Semiconductor): This part differs in configuration as a single diode rather than a diode pair, and provides significantly higher current capacity (10 A versus 3 A). The reverse voltage rating is 45 V with forward voltage of 550 mV @ 5 A. This part is classified as not for new designs. The single diode configuration and higher current rating make this substitute applicable only in applications where the circuit design can accommodate a single diode topology and where the increased current capacity is beneficial or neutral to the application.

Frequently Asked Questions (FAQ)

Q: Can MBRD640CTT4G be used as a direct replacement for STPS640CB?

A: Yes. The MBRD640CTT4G maintains identical electrical specifications for diode configuration, reverse voltage (40 V), and average rectified current (3 A per diode). Both devices use the same TO-252-3 DPAK package. The forward voltage specification differs by 70 mV at rated current; this difference must be evaluated within the specific circuit application to confirm acceptability.

Q: What is the primary difference between MBRD640CTT4G and MBRD650CTT4G?

A: The MBRD650CTT4G has a higher maximum reverse voltage rating of 50 V compared to 40 V for the MBRD640CTT4G. All other electrical parameters and the package type remain identical. The MBRD650CTT4G is selected when the application requires voltage margin above 40 V.

Q: Why is RB085BM-40TL listed as a substitute if it has different specifications?

A: The RB085BM-40TL is included because it shares the same package type (TO-252-3 DPAK) and Schottky technology. However, it is a single diode configuration with 10 A current rating, differing significantly from the STPS640CB's 1 pair common cathode configuration and 3 A rating. This part is applicable only in circuit designs that can accommodate a single diode topology.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. The STPS640CB and all identified substitute parts (MBRD640CTT4G, MBRD650CTT4G, and RB085BM-40TL) are ROHS3 compliant with moisture sensitivity level 1 (unlimited).

Q: What is the product status of each substitute part?

A: MBRD640CTT4G and MBRD650CTT4G are classified as active products. RB085BM-40TL is classified as not for new designs. For new design implementations, MBRD640CTT4G or MBRD650CTT4G are the recommended selections.

Q: Do all substitute parts use the same package footprint?

A: Yes. The STPS640CB and all substitute parts use the TO-252-3 DPAK (2 Leads + Tab) SC-63 package, ensuring PCB footprint compatibility for surface mount assembly.

Q: How does forward voltage affect substitute selection?

A: Forward voltage specifications vary among substitutes. The STPS640CB specifies 630 mV @ 3 A, while MBRD640CTT4G and MBRD650CTT4G specify 700 mV @ 3 A. The RB085BM-40TL specifies 550 mV @ 5 A. Forward voltage drop directly affects power dissipation and circuit efficiency; the application circuit must be evaluated to confirm the substitute's forward voltage is acceptable.

Q: Can RB085BM-40TL be used in applications designed for the STPS640CB?

A: Only if the circuit design can accommodate a single diode topology instead of a diode pair common cathode configuration. The higher current rating (10 A) does not automatically make it suitable; the circuit topology must be compatible with the single diode configuration.

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