CDST-21S-G Equivalent & Substitute Parts

Part Overview

The CDST-21S-G is a general-purpose diode array manufactured by Comchip Technology, configured as 1 pair series connection with 250 V reverse voltage rating and 200 mA average rectified current per diode. The device is packaged in SOT-23-3 (TO-236-3, SC-59) surface mount configuration. This part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility within the specified electrical and mechanical parameters.

Substiute Parts

CDST-21S-G

Comchip TechnologyIn Stock: 2087CDST-21S-G Datasheet

Current PartRFQ

BAS21S-HF

Comchip TechnologyIn Stock: 8984BAS21S-HF Datasheet

DirectRFQ

NSVBAS21SLT1G

onsemiIn Stock: 35112NSVBAS21SLT1G Datasheet

MFR RecommendedRFQ

BAS21S RFG

Taiwan Semiconductor CorporationIn Stock: 6684BAS21S RFG Datasheet

Parametric EquivalentRFQ

BAV23S

Good-Ark SemiconductorIn Stock: 305194BAV23S Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CDST-21S-G is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Voltage - DC Reverse (Vr) (Max): 250 V minimum
• Package / Case: TO-236-3, SC-59, SOT-23-3 surface mount
• Diode Configuration: 1 Pair Series Connection
• Reverse Recovery Time (trr): 50 ns
• Voltage - Forward (Vf) (Max) @ If: 1.25 V @ 200 mA
• RoHS3 Compliance

Current Rating Flexibility: Current - Average Rectified (Io) per diode may be equal to or greater than 200 mA, as higher current ratings provide functional equivalence in applications requiring 200 mA or less.

Substitute Classification:

Direct Manufacturer Substitute (Comchip Technology):

• BAS21S-HF: Higher current rating (400 mA) with identical voltage and package specifications

Manufacturer Recommended Substitute (onsemi):

• NSVBAS21SLT1G: Intermediate current rating (225 mA) with active product status

Parametric Equivalents:

• BAS21S RFG (Taiwan Semiconductor Corporation): Identical electrical specifications with active status
• BAV23S (Good-Ark Semiconductor): Intermediate current rating (225 mA) with active status and extended temperature range

Parameter Comparison

Engineering Selection Recommendations

BAS21S-HF (Comchip Technology): Direct manufacturer substitute with active product status. Current rating of 400 mA exceeds the 200 mA requirement, providing operational margin. Identical voltage, package, and recovery time specifications. Recommended for new designs requiring Comchip sourcing continuity.

NSVBAS21SLT1G (onsemi): Manufacturer-recommended substitute with active product status and extended operating temperature range (-55°C to 150°C). Current rating of 225 mA accommodates the 200 mA requirement. Suitable for applications requiring broader temperature performance and onsemi supply chain integration.

BAS21S RFG (Taiwan Semiconductor Corporation): Parametric equivalent with identical electrical specifications to the original CDST-21S-G. Active product status with extended operating temperature range. Appropriate for applications requiring exact current rating matching and Taiwan Semiconductor Corporation sourcing.

BAV23S (Good-Ark Semiconductor): Parametric equivalent with 225 mA current rating and active product status. Extended operating temperature range and highest inventory availability (305,100 pcs). Suitable for high-volume applications and extended temperature environments.

All substitute parts maintain ROHS3 compliance, MSL 1 rating, and identical package specifications, ensuring direct PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can BAS21S-HF replace CDST-21S-G in all applications?

A: Yes. BAS21S-HF maintains identical voltage (250 V), forward voltage (1.25 V @ 200 mA), reverse recovery time (50 ns), and package specifications (SOT-23-3). The higher current rating (400 mA vs. 200 mA) provides operational margin without functional degradation.

Q: What is the difference between the substitute parts?

A: All substitutes meet the mandatory 250 V reverse voltage and SOT-23-3 package requirements. Differences exist in current ratings (200 mA to 400 mA), operating temperature ranges, and manufacturer sourcing. BAS21S RFG matches the original 200 mA specification exactly. BAS21S-HF and BAV23S provide higher current ratings (225-400 mA). NSVBAS21SLT1G offers intermediate current (225 mA) with onsemi sourcing.

Q: Are all substitutes pin-compatible with CDST-21S-G?

A: Yes. All substitute parts use the TO-236-3 (SC-59, SOT-23-3) package with identical pinout configuration for 1 pair series connection diode arrays. Direct PCB replacement is possible without layout modification.

Q: Which substitute has the best availability?

A: BAV23S (Good-Ark Semiconductor) has the highest inventory at 305,100 pcs. NSVBAS21SLT1G (onsemi) has 35,100 pcs. BAS21S-HF (Comchip Technology) has 8,941 pcs. BAS21S RFG (Taiwan Semiconductor Corporation) has 6,655 pcs.

Q: Do all substitutes comply with RoHS3 and REACH requirements?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and carry MSL 1 (unlimited) moisture sensitivity rating, matching the original CDST-21S-G specifications.

Q: What is the significance of the 50 ns reverse recovery time across all parts?

A: The 50 ns reverse recovery time is a critical parameter maintained across all substitutes. This specification determines switching speed and is essential for applications requiring fast diode response. All substitutes preserve this parameter, ensuring functional equivalence in time-sensitive circuits.

Q: Can I use a substitute with higher current rating in a 200 mA application?

A: Yes. Higher current ratings (225 mA or 400 mA) are functionally equivalent in applications designed for 200 mA operation. The diode will operate within its safe operating area with additional thermal margin. No circuit modification is required.