RB491D-TP Schottky Diode Equivalent & Substitute Parts

Part Overview

The RB491D-TP is a Schottky rectifier diode manufactured by Micro Commercial Co, rated for 20 V DC reverse voltage and 1 A average rectified current in a surface mount SOT-23 package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The part is RoHS3 compliant with unlimited moisture sensitivity level (MSL 1) and is suitable for fast recovery applications requiring switching speeds of 500 ns or less at currents exceeding 200 mA.

Substiute Parts

RB491D-TP

Micro Commercial CoIn Stock: 1182RB491D-TP Datasheet

Current PartRFQ

ZHCS1000TA

Diodes IncorporatedIn Stock: 77227ZHCS1000TA Datasheet

SimilarRFQ

RB491DT146

Rohm SemiconductorIn Stock: 89402RB491DT146 Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the RB491D-TP are selected based on strict electrical and mechanical compatibility criteria. The primary substitution parameters are:

Electrical Compatibility Requirements:

• Voltage - DC Reverse (Vr) rating must equal or exceed 20 V
• Current - Average Rectified (Io) must equal or exceed 1 A
• Technology must be Schottky
• Speed classification must support Fast Recovery ≤ 500ns at currents > 200mA
• Forward voltage (Vf) must not exceed 500 mV @ 1 A to maintain circuit performance

Mechanical Compatibility Requirements:

• Package / Case must be TO-236-3, SC-59, or SOT-23-3
• Mounting Type must be Surface Mount
• Operating Temperature - Junction must support 125°C maximum

Compliance Requirements:

• RoHS3 Compliant status required
• Moisture Sensitivity Level (MSL) must be 1 (Unlimited)

Two substitute parts meet these criteria: ZHCS1000TA (parametric upgrade with higher voltage rating) and RB491DT146 (parametric equivalent with identical electrical specifications).

Parameter Comparison

Engineering Selection Recommendations

RB491DT146 (Parametric Equivalent)

The RB491DT146 manufactured by Rohm Semiconductor is a parametric equivalent substitute. It provides identical electrical specifications: 20 V DC reverse voltage, 1 A average rectified current, 450 mV forward voltage at 1 A, and 200 µA reverse leakage current at 20 V. The part maintains the same fast recovery speed classification and operating temperature range. RB491DT146 is active in production with 89,300 pieces in stock, ensuring procurement continuity. It carries ROHS3 compliance and MSL 1 rating identical to the main part. The supplier device package designation differs (SMD3 versus SOT-23), but both conform to the TO-236-3, SC-59, SOT-23-3 package family standard.

ZHCS1000TA (Parametric Upgrade)

The ZHCS1000TA manufactured by Diodes Incorporated is a parametric upgrade substitute with enhanced voltage rating of 40 V DC reverse (versus 20 V). This part maintains 1 A average rectified current and fast recovery speed classification. Forward voltage is 500 mV at 1 A, representing a 50 mV increase from the main part specification. Reverse leakage current is 100 µA at 30 V, demonstrating improved leakage characteristics. ZHCS1000TA is active in production with 77,200 pieces in stock. It meets ROHS3 compliance and MSL 1 requirements. The higher voltage rating provides additional design margin in applications where the 20 V specification is adequate but margin enhancement is beneficial. The supplier device package is SOT-23-3, conforming to the same package family standard.

Both substitutes are suitable for direct replacement based on compliance status and active production availability. Selection between RB491DT146 and ZHCS1000TA depends on circuit voltage requirements and design margin considerations.

Frequently Asked Questions (FAQ)

Q: Can ZHCS1000TA replace RB491D-TP in all applications?

A: ZHCS1000TA is electrically compatible with RB491D-TP for circuits operating at 20 V or below. The 40 V rating provides additional voltage margin. The 50 mV increase in forward voltage (500 mV versus 450 mV at 1 A) must be evaluated in applications where forward voltage drop affects circuit performance. Both parts share identical current rating, speed classification, and package family.

Q: Is RB491DT146 a direct replacement for RB491D-TP?

A: Yes. RB491DT146 provides identical electrical specifications: 20 V reverse voltage, 1 A current, 450 mV forward voltage, and 200 µA reverse leakage. Both parts use the same package family (TO-236-3, SC-59, SOT-23-3) and share identical compliance certifications. The supplier device package designation differs (SMD3 versus SOT-23), but this reflects internal supplier packaging conventions without affecting PCB assembly compatibility.

Q: What is the difference between SOT-23 and SOT-23-3 package designations?

A: SOT-23 and SOT-23-3 refer to the same physical package family (TO-236-3, SC-59). The "-3" designation explicitly indicates a 3-lead configuration. Both designations are equivalent for component selection and PCB assembly purposes.

Q: Why does ZHCS1000TA have lower reverse leakage current?

A: ZHCS1000TA specifies 100 µA reverse leakage at 30 V, while RB491D-TP specifies 200 µA at 20 V. These measurements occur at different voltage levels, making direct comparison inappropriate. Leakage current increases with applied voltage; the ZHCS1000TA measurement at higher voltage (30 V) with lower leakage indicates superior leakage characteristics across its operating range.

Q: Are all three parts RoHS3 compliant?

A: Yes. RB491D-TP, ZHCS1000TA, and RB491DT146 are all ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity level. All parts are REACH unaffected and classified under ECCN EAR99.

Q: Which substitute should be selected for new designs?

A: For new designs, either substitute is acceptable based on circuit requirements. RB491DT146 is recommended for direct replacement of existing RB491D-TP designs due to parametric equivalence. ZHCS1000TA is recommended when design margin enhancement through higher voltage rating is beneficial. Both parts are active in production with substantial inventory availability.