LLSD103B-TP Equivalent & Substitute Parts

Part Overview

The LLSD103B-TP is a Schottky rectifier diode manufactured by Micro Commercial Co, rated for 30V DC reverse voltage and 350mA average rectified current in a Mini MELF surface mount package. This component is classified as obsolete, necessitating identification of functionally equivalent alternatives for new designs and production continuity. Substitute parts must maintain electrical performance within the specified voltage and current parameters while accommodating available packaging options.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	30 V
Current - Average Rectified (Io)	350 mA
Voltage - Forward (Vf) (Max) @ If	600 mV @ 200 mA
Reverse Recovery Time (trr)	10 ns
Current - Reverse Leakage @ Vr	5 µA @ 20 V
Technology	Schottky
Mounting Type	Surface Mount
Package / Case	DO-213AC, MINI-MELF, SOD-80
Operating Temperature - Junction	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the LLSD103B-TP is determined by the following critical parameters: voltage rating (30V minimum), current capacity, forward voltage characteristics, reverse recovery time, and surface mount package compatibility. The LLSD103B-TP operates at 350mA average rectified current with a 10ns reverse recovery time specification.

Substitute parts are grouped into two categories:

Direct Current Rating Match: The SD103BW-TP maintains identical electrical specifications (30V, 350mA, 600mV @ 200mA, 10ns trr) and differs only in package format (SOD-123 versus Mini MELF). This part provides functional equivalence with alternative packaging.

Reduced Current Rating Substitutes: Parts including BAS85-GS08, BAS85-GS18, BAS85-M-08, BAS85-M-18, LL42-GS08, LL42-GS18, and LL43-GS18 are rated for 200mA average rectified current, representing a 43% reduction from the original 350mA specification. These parts maintain the 30V voltage rating and Mini MELF packaging but operate within lower current parameters. Selection of reduced-current alternatives requires circuit analysis to confirm application compatibility.

Parameter Comparison

Parameter	LLSD103B-TP	SD103BW-TP	BAS85-GS08	BAS85-GS18	BAS85-M-08	BAS85-M-18	LL42-GS08	LL42-GS18	LL43-GS18
Manufacturer	Micro Commercial Co	Micro Commercial Co	Vishay	Vishay	Vishay	Vishay	Vishay	Vishay	Vishay
Voltage - DC Reverse (Vr) (Max)	30 V	30 V	30 V	30 V	30 V	30 V	30 V	30 V	30 V
Current - Average Rectified (Io)	350 mA	350 mA	200 mA	200 mA	200 mA	200 mA	200 mA	200 mA	200 mA
Voltage - Forward (Vf) (Max) @ If	600 mV @ 200 mA	600 mV @ 200 mA	800 mV @ 100 mA	800 mV @ 100 mA	800 mV @ 100 mA	800 mV @ 100 mA	650 mV @ 50 mA	650 mV @ 50 mA	450 mV @ 15 mA
Reverse Recovery Time (trr)	10 ns	10 ns	5 ns	5 ns	Not specified	Not specified	5 ns	5 ns	5 ns
Current - Reverse Leakage @ Vr	5 µA @ 20 V	5 µA @ 20 V	2 µA @ 25 V	2 µA @ 25 V	2 µA @ 25 V	2 µA @ 25 V	500 nA @ 25 V	500 nA @ 25 V	500 nA @ 25 V
Package / Case	DO-213AC, MINI-MELF, SOD-80	SOD-123	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80	DO-213AC, MINI-MELF, SOD-80
Operating Temperature - Junction	-55°C ~ 150°C	-55°C ~ 125°C	125°C (Max)	125°C (Max)	125°C (Max)	125°C (Max)	-55°C ~ 125°C	125°C (Max)	125°C (Max)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Automotive Grade	Not specified	Not specified	Not specified	Yes (AEC-Q101)	Yes (AEC-Q101)	Yes (AEC-Q101)	Not specified	Yes (AEC-Q101)	Yes (AEC-Q101)

Engineering Selection Recommendations

Primary Substitute - SD103BW-TP: This part is the direct electrical equivalent of the LLSD103B-TP, maintaining all critical specifications including 350mA current rating, 30V voltage rating, 600mV forward voltage at 200mA, and 10ns reverse recovery time. The SD103BW-TP is in active production status with ROHS3 compliance. The only difference is package format (SOD-123 versus Mini MELF). Selection of this part requires PCB layout modification to accommodate the SOD-123 footprint.

Secondary Substitutes - 200mA Rated Parts: The BAS85-GS08, BAS85-GS18, BAS85-M-08, BAS85-M-18, LL42-GS08, LL42-GS18, and LL43-GS18 parts are suitable for applications where circuit current requirements do not exceed 200mA. These parts maintain Mini MELF packaging compatibility with the original LLSD103B-TP, eliminating PCB redesign requirements. Parts designated with automotive grade (BAS85-GS18, BAS85-M-08, BAS85-M-18, LL42-GS18, LL43-GS18) carry AEC-Q101 qualification for automotive applications.

Temperature Considerations: The LLSD103B-TP operates to 150°C junction temperature. Most substitute parts are rated to 125°C maximum junction temperature. Applications requiring operation above 125°C require circuit analysis to confirm thermal compatibility.

Compliance Status: All substitute parts maintain ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, matching the original part specifications.

Frequently Asked Questions (FAQ)

Q: Can SD103BW-TP directly replace LLSD103B-TP without circuit modification?

A: SD103BW-TP provides electrical equivalence but requires PCB layout modification. The SD103BW-TP uses SOD-123 packaging while LLSD103B-TP uses Mini MELF (SOD-80). Footprint and land pattern changes are necessary. All electrical parameters remain identical.

Q: What is the impact of using a 200mA-rated diode in place of the 350mA LLSD103B-TP?

A: The 200mA-rated substitutes (BAS85 series, LL42 series, LL43 series) operate within reduced current specifications. Circuit analysis must confirm that maximum operating current does not exceed 200mA. Exceeding this rating results in diode failure.

Q: Are the Vishay BAS85 and LL-series parts pin-compatible with LLSD103B-TP?

A: Yes. All substitute parts use Mini MELF (SOD-80) or SOD-123 packaging with identical pin configurations for Schottky diodes. Pin compatibility is maintained across all listed substitutes.

Q: Which substitute parts are suitable for automotive applications?

A: BAS85-GS18, BAS85-M-08, BAS85-M-18, LL42-GS18, and LL43-GS18 carry AEC-Q101 automotive qualification. These parts are suitable for automotive-grade circuit designs.

Q: Does the lower reverse recovery time (5ns) of substitute parts affect circuit performance?

A: Substitute parts with 5ns reverse recovery time (versus 10ns for LLSD103B-TP) represent improved switching characteristics. This change is not detrimental and typically improves circuit efficiency in switching applications.

Q: What is the significance of forward voltage differences among substitute parts?

A: Forward voltage varies across substitutes: LLSD103B-TP and SD103BW-TP specify 600mV @ 200mA; BAS85 series specify 800mV @ 100mA; LL42 series specify 650mV @ 50mA; LL43 series specify 450mV @ 15mA. Forward voltage affects power dissipation and circuit efficiency. Selection depends on operating current levels and thermal budget.

Q: Can LLSD103B-TP be used in new designs given its obsolete status?

A: LLSD103B-TP is classified as obsolete and not recommended for new designs. Active production alternatives (SD103BW-TP for direct equivalence, or 200mA-rated parts for reduced-current applications) ensure long-term supply availability and design continuity.

Q: What packaging options are available for Mini MELF-compatible substitutes?

A: All 200mA-rated substitutes (BAS85 series, LL42 series, LL43 series) are available in Mini MELF (SOD-80) packaging, maintaining footprint compatibility with LLSD103B-TP. SD103BW-TP uses SOD-123 packaging, requiring PCB modification.

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