FLLD261TA Equivalent & Substitute Parts

Part Overview

The FLLD261TA is a general-purpose diode array manufactured by Diodes Incorporated, configured as a 1 Pair Series Connection with a maximum reverse voltage rating of 100 V and average rectified current of 250 mA per diode. The device is housed in a Surface Mount TO-236-3 (SOT-23-3) package. This part is classified as obsolete, necessitating identification of equivalent substitute components that maintain functional compatibility within specified electrical and mechanical parameters.

Substiute Parts

FLLD261TA

Diodes IncorporatedIn Stock: 15520FLLD261TA Datasheet

Current PartRFQ

BAS31,215

Nexperia USA Inc.In Stock: 48420BAS31,215 Datasheet

MFR RecommendedRFQ

MMBD1503A

onsemiIn Stock: 381039MMBD1503A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FLLD261TA is determined by the following critical parameters:

Package Compatibility: All substitute parts must use the TO-236-3 (SOT-23-3) Surface Mount package to ensure mechanical and electrical compatibility with existing PCB layouts.

Diode Configuration: Substitute parts must maintain the 1 Pair Series Connection configuration to preserve circuit functionality.

Electrical Parameters: Substitute parts must satisfy the following conditions:

• Voltage - DC Reverse (Vr) rating must be equal to or greater than 100 V
• Current - Average Rectified (Io) rating must be equal to or greater than 250 mA per diode
• Forward voltage (Vf) characteristics must be compatible with circuit design requirements
• Operating temperature range must encompass the application requirements

Speed Classification: Substitute parts classified as Fast Recovery (≤ 500ns, > 200mA) or faster are acceptable.

The identified substitute parts meet these criteria while offering improved product status (Active) and enhanced compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

BAS31,215 (Nexperia USA Inc.): This substitute offers Active product status with ROHS3 compliance and AEC-Q100 automotive qualification. The part maintains the required 1 Pair Series Connection configuration and SOT-23-3 package. The reverse voltage rating of 90 V is below the FLLD261TA specification of 100 V; therefore, this substitute is suitable only for applications where the circuit operates at or below 90 V reverse bias conditions. The forward voltage is lower (1 V vs. 1.4 V), and the reverse recovery time is significantly faster (50 ns vs. 400 ns), which may alter circuit switching characteristics. Current rating matches at 250 mA.

MMBD1503A (onsemi): This substitute offers Active product status with ROHS3 compliance. The part maintains the required 1 Pair Series Connection configuration and SOT-23-3 package. The reverse voltage rating of 200 V exceeds the FLLD261TA specification, providing margin for overvoltage protection. However, the average rectified current rating is 200 mA, which is below the FLLD261TA specification of 250 mA; therefore, this substitute is suitable only for applications where the circuit operates at or below 200 mA per diode. The forward voltage is lower (1.1 V vs. 1.4 V), and the speed classification differs (Small Signal vs. Fast Recovery).

Both substitutes provide improved product availability and regulatory compliance compared to the obsolete FLLD261TA.

Frequently Asked Questions (FAQ)

Q: Can the BAS31,215 be used as a direct replacement for the FLLD261TA?

A: The BAS31,215 is mechanically compatible (identical SOT-23-3 package) and maintains the same diode configuration. However, the reverse voltage rating is 90 V compared to the FLLD261TA's 100 V. Substitution is valid only if the circuit operates at reverse bias voltages of 90 V or below. The lower forward voltage and faster recovery time may affect circuit performance in timing-sensitive applications.

Q: Can the MMBD1503A be used as a direct replacement for the FLLD261TA?

A: The MMBD1503A is mechanically compatible (identical SOT-23-3 package) and maintains the same diode configuration. However, the average rectified current rating is 200 mA compared to the FLLD261TA's 250 mA. Substitution is valid only if the circuit operates at average rectified currents of 200 mA or below. The higher reverse voltage rating provides additional margin for overvoltage conditions.

Q: What is the significance of the SOT-23-3 package specification?

A: The SOT-23-3 package (also designated TO-236-3 or SC-59) is a three-pin Surface Mount package. All identified substitutes use this identical package, ensuring compatibility with existing PCB layouts, solder reflow profiles, and assembly processes without modification.

Q: How do forward voltage differences affect circuit operation?

A: Forward voltage (Vf) determines the voltage drop across the diode during conduction. The FLLD261TA specifies 1.4 V @ 200 mA, while substitutes specify lower values (BAS31,215: 1 V; MMBD1503A: 1.1 V). Lower forward voltage reduces power dissipation but may alter circuit biasing, voltage regulation, or signal conditioning characteristics. Circuit validation is necessary when forward voltage differs significantly.

Q: What does "1 Pair Series Connection" mean?

A: This configuration indicates the diode array contains two diodes connected in series within a single package. Both substitute parts maintain this configuration, preserving the electrical topology of the original circuit.

Q: Are there temperature range differences between the main part and substitutes?

A: The FLLD261TA specifies -55°C to 150°C junction operating temperature. The BAS31,215 and MMBD1503A specify 150°C maximum junction temperature without a minimum specification. For applications requiring operation below 0°C, the FLLD261TA's extended lower temperature range may be necessary.

Q: What is the difference between Fast Recovery and Small Signal speed classifications?

A: Fast Recovery diodes (≤ 500ns, > 200mA) are optimized for applications requiring rapid switching at higher currents. Small Signal diodes (≤ 200mA) are optimized for low-current applications. The MMBD1503A's Small Signal classification indicates it is not optimized for the 250 mA current level of the original FLLD261TA.

Q: Why is product status (Obsolete vs. Active) important?

A: Obsolete parts have discontinued manufacturing and limited inventory availability. Active parts have ongoing production and assured long-term supply. Both identified substitutes are Active, providing supply chain continuity and reduced procurement risk compared to the obsolete FLLD261TA.

Q: What does RoHS3 compliance mean?

A: RoHS3 (Restriction of Hazardous Substances Directive 3) compliance indicates the component meets European Union environmental regulations restricting hazardous materials. Both substitutes are RoHS3 compliant, while the FLLD261TA is non-compliant. This is significant for applications subject to environmental regulations or customer requirements.