BAT54S Equivalent & Substitute Parts

Part Overview

The BAT54S is a Schottky diode array in a 1 Pair Series Connection configuration, rated for 30 V DC reverse voltage and 200 mA average rectified current per diode. Manufactured by onsemi, this component is packaged in the TO-236-3 (SOT-23-3) surface mount form factor. The BAT54S is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and ongoing production requirements. Active alternatives maintain the same electrical specifications and package footprint, ensuring direct replacement capability in existing circuit applications.

Key Parameters

Parameter	Value	Unit
Diode Configuration	1 Pair Series Connection	—
Technology	Schottky	—
Voltage - DC Reverse (Vr) (Max)	30	V
Current - Average Rectified (Io) (per Diode)	200	mA
Voltage - Forward (Vf) (Max) @ If	800 mV @ 100 mA	—
Reverse Recovery Time (trr)	5	ns
Current - Reverse Leakage @ Vr	2	µA @ 25 V
Operating Temperature - Junction	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the BAT54S is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Diode Configuration: 1 Pair Series Connection
Technology: Schottky
Voltage - DC Reverse (Vr) (Max): 30 V minimum
Current - Average Rectified (Io) (per Diode): 200 mA minimum
Voltage - Forward (Vf) (Max) @ If: 800 mV @ 100 mA or lower
Reverse Recovery Time (trr): 5 ns or lower
Current - Reverse Leakage @ Vr: 2 µA @ 25 V or lower
Package / Case: TO-236-3, SC-59, SOT-23-3 (or compatible footprint)
Mounting Type: Surface Mount

Direct Equivalents maintain all electrical parameters and identical package specifications, enabling pin-for-pin replacement without circuit modification.

Similar Parts meet the core electrical requirements but may exhibit minor variations in secondary parameters such as reverse leakage current, forward voltage, or operating temperature range. These parts are functionally compatible within the application's design margins.

Upgrade Parts from alternative manufacturers provide equivalent or superior electrical performance with active product status and enhanced compliance certifications (RoHS3, AEC-Q101 where applicable).

Parameter Comparison

Part Number	Manufacturer	Product Status	Vr (Max) [V]	Io (per Diode) [mA]	Vf (Max) @ If [mV]	trr [ns]	Ir @ Vr [µA]	Tj (Max) [°C]	Package	RoHS Status
BAT54S	onsemi	Obsolete	30	200	800 @ 100	5	2 @ 25	150	SOT-23-3	—
BAT54SLT1G	onsemi	Active	30	200	800 @ 100	5	2 @ 25	125	SOT-23-3	ROHS3
SBAT54SLT1G	onsemi	Active	30	200	800 @ 100	5	2 @ 25	150	SOT-23-3	ROHS3
MMBD452LT1G	onsemi	Active	30	—	—	5	—	125	SOT-23-3	ROHS3
SBAS40-04LT1G	onsemi	Active	40	120	1000 @ 40	—	1 @ 25	150	SOT-23-3	ROHS3
BAT5404E6327HTSA1	Infineon Technologies	Active	30	200	800 @ 100	5	2 @ 25	150	SOT-23-3	ROHS3
BAT54S-7-F	Diodes Incorporated	Active	30	200	800 @ 100	5	2 @ 25	150	SOT-23-3	ROHS3
BAT54STA	Diodes Incorporated	Active	30	200	1000 @ 100	5	4 @ 25	125	SOT-23-3	ROHS3
BAR43S-TP	Micro Commercial Co	Active	30	200	800 @ 100	5	0.5 @ 25	150	SOT-23-3	—
BAT5404WH6327XTSA1	Infineon Technologies	Active	30	200	800 @ 100	5	2 @ 25	150	SOT-323	ROHS3
BAT54S,235	Nexperia USA Inc.	Active	30	200	800 @ 100	5	2 @ 25	150	SOT-23-3	ROHS3

Engineering Selection Recommendations

Direct Replacement (Pin-for-Pin Compatible):

The following parts provide complete electrical and mechanical equivalence to the BAT54S and are suitable for direct substitution in existing designs:

BAT54SLT1G (onsemi): Active product with identical electrical specifications. Maximum junction temperature reduced to 125°C. RoHS3 compliant. Recommended for new designs requiring onsemi sourcing.
SBAT54SLT1G (onsemi): Automotive-grade variant with full temperature range (-55°C to 150°C) matching the original BAT54S. RoHS3 compliant. Suitable for automotive and extended temperature applications.
BAT5404E6327HTSA1 (Infineon Technologies): Active equivalent from alternative manufacturer. Maintains all electrical parameters and operating temperature range. RoHS3 compliant. Provides supply chain diversification.
BAT54S-7-F (Diodes Incorporated): Active equivalent with extended operating temperature range (-65°C to 150°C). RoHS3 compliant. Offers superior low-temperature performance.
BAT54S,235 (Nexperia USA Inc.): Automotive-qualified equivalent (AEC-Q101) with full temperature range. RoHS3 compliant. Recommended for automotive applications requiring qualification documentation.

Functionally Compatible Alternatives:

SBAS40-04LT1G (onsemi): Schottky diode array with higher reverse voltage rating (40 V) but reduced current rating (120 mA per diode). Suitable for applications where higher voltage margin is required and current demand does not exceed 120 mA. Automotive-qualified (AEC-Q101).
BAR43S-TP (Micro Commercial Co): Equivalent electrical specifications with superior reverse leakage characteristics (500 nA vs. 2 µA). Suitable for low-leakage applications. Limited compliance documentation available.
BAT54STA (Diodes Incorporated): Slightly elevated forward voltage (1 V @ 100 mA) and reverse leakage (4 µA @ 25 V) with reduced maximum junction temperature (125°C). Acceptable for applications with relaxed forward voltage and leakage requirements.

Package Variant:

BAT5404WH6327XTSA1 (Infineon Technologies): Identical electrical specifications in SOT-323 (SC-70) package. Suitable only for designs using SOT-323 footprint. Not compatible with SOT-23-3 PCB layouts.

Similar Performance (Reduced Current Rating):

MMBD452LT1G (onsemi): RF-optimized Schottky diode with 30 V rating but unspecified current rating. Characterized by low capacitance (1.5 pF @ 15 V, 1 MHz). Suitable for RF and high-frequency applications where current demand is below 200 mA.

Frequently Asked Questions (FAQ)

Q: Can BAT54SLT1G directly replace BAT54S without PCB modification?

A: Yes. BAT54SLT1G is electrically and mechanically equivalent, with identical SOT-23-3 package footprint and pinout. The only difference is reduced maximum junction temperature (125°C vs. 150°C). Verify that your application's thermal environment does not exceed 125°C at the junction.

Q: What is the difference between BAT54SLT1G and SBAT54SLT1G?

A: SBAT54SLT1G is the automotive-grade variant with full operating temperature range (-55°C to 150°C) matching the original BAT54S. BAT54SLT1G has a reduced maximum junction temperature of 125°C. Select SBAT54SLT1G for automotive applications or designs requiring the full temperature range.

Q: Is BAT5404WH6327XTSA1 compatible with existing BAT54S PCB layouts?

A: No. BAT5404WH6327XTSA1 uses SOT-323 (SC-70) package, which has a different footprint than the SOT-23-3 package of BAT54S. PCB redesign is required for this substitution.

Q: Can SBAS40-04LT1G replace BAT54S in all applications?

A: SBAS40-04LT1G has a higher reverse voltage rating (40 V) but lower current rating (120 mA per diode vs. 200 mA). It is suitable only for applications where the current requirement does not exceed 120 mA. Verify circuit current demands before substitution.

Q: What does RoHS3 compliance mean for component selection?

A: RoHS3 compliance indicates the component meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. All active substitute parts listed are RoHS3 compliant, suitable for modern manufacturing and environmental regulations.

Q: Are automotive-qualified parts (AEC-Q101) required for my application?

A: AEC-Q101 qualification is required only for automotive applications. SBAT54SLT1G, SBAS40-04LT1G, and BAT54S,235 carry automotive qualification. For non-automotive applications, any active equivalent is acceptable.

Q: What is the significance of reverse recovery time (trr) in Schottky diode selection?

A: Reverse recovery time determines switching speed. All listed equivalents maintain 5 ns trr, ensuring identical high-frequency performance. This parameter is critical for switching power supplies and RF applications.

Q: How does reverse leakage current affect circuit performance?

A: Reverse leakage current (Ir) affects power consumption and circuit accuracy in precision applications. BAT54S specifies 2 µA @ 25 V. BAR43S-TP offers superior performance at 500 nA, while BAT54STA exhibits higher leakage at 4 µA. Select based on application sensitivity to leakage current.

Q: Can I use MMBD452LT1G as a general replacement for BAT54S?

A: MMBD452LT1G is RF-optimized with low capacitance characteristics but lacks specified current rating. It is suitable for RF and high-frequency applications where current demand is confirmed below 200 mA. For general-purpose rectification, use standard equivalents (BAT54SLT1G, SBAT54SLT1G, or BAT54S-7-F).

Q: What packaging options are available for BAT54S equivalents?

A: All direct equivalents are available in SOT-23-3 (TO-236-3, SC-59) surface mount package. BAT5404WH6327XTSA1 offers SOT-323 (SC-70) as an alternative for space-constrained designs. Verify PCB footprint compatibility before selection.

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