Nexperia USA Inc. BAS31,215

Overview

BAS31,215 from Nexperia is a dual-series general-purpose controlled avalanche diode in SOT23 package, rated for 110 V repetitive peak reverse voltage, 600 mA repetitive peak forward current, and 50 ns reverse recovery time; used for high-speed switching in compact surface-mounted power management and signal routing circuits.

For engineers reviewing the BAS31,215 datasheet, BAS31,215 pinout, BAS31,215 application, or BAS31,215 equivalent, key selection criteria include series-connected dual-diode topology, avalanche energy handling (5 mJ), thermal resistance (360 K/W junction-to-tie-point), and FR4 PCB derating behavior at elevated ambient temperatures.

Technical Context

The BAS31 integrates two identical planar silicon diodes in series within a single SOT23-3 package, enabling higher blocking voltage per unit footprint than single-diode alternatives. Its controlled avalanche capability supports transient energy absorption without catastrophic failure under repetitive surge conditions.

Designed for operation up to 150 °C junction temperature, it delivers stable reverse leakage (<100 nA at 90 V, 25 °C) and predictable forward voltage (≤900 mV at 100 mA), with thermal performance governed by R_{th j-tp} = 360 K/W and R_{th j-a} = 500 K/W on FR4.

Key Specifications

Pinout & Package

Supplied in SOT23 (TO-236AB) plastic surface-mount package: 3-lead, rectangular outline, 1.3 mm × 2.9 mm footprint, 1.1 mm height, with gull-wing leads and defined tie-point thermal path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-series avalanche diode applications.

Compared with BAS31,215, BAS31,115 offers identical performance in a different packaging format, while MMBD301LT1G trades avalanche robustness for faster switching-making it viable only in non-surge environments requiring sub-10 ns recovery.

Availability

BAS31,215 is available at Aetrix Electronics and suitable for automotive door modules, industrial PLC input stages, and consumer appliance motor control circuits requiring stable component supply and long-term lifecycle continuity.

Supply support for BAS31,215 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a global leader in high-volume discrete, logic, and PowerMOS semiconductors, spun off from NXP in 2017 and focused on automotive, industrial, computing, and consumer markets.

The BAS31 belongs to Nexperia's General Purpose Controlled Avalanche Diode product line, engineered for reliable transient suppression and high-speed switching in space-constrained SMT designs.

FAQ

What is the maximum continuous forward current rating for BAS31,215?

The maximum continuous forward current is 150 mA when both diodes in the series string are loaded, as specified in the Limiting Values table under "double diode loaded" condition. This derating accounts for thermal coupling between diodes in the shared SOT23 package and must be applied at Tamb = 25 °C on FR4 PCB.

Does BAS31,215 support bidirectional clamping?

No - BAS31,215 is a unidirectional series-connected diode pair with anode (pin 1) and cathode (pin 3) terminals; it conducts only from pin 1 to pin 3. For bidirectional protection, two BAS31 devices must be connected in anti-parallel or a dedicated bidirectional TVS device should be used.

Can BAS31,215 replace BAS29 in existing designs?

No - BAS29 is a single-diode device in the same SOT23 package, while BAS31 contains two diodes in series. Substituting BAS31 for BAS29 doubles the forward voltage drop (~1.8 V vs. ~0.9 V at 100 mA) and changes blocking behavior, requiring circuit-level validation of voltage margins and power dissipation.

What is the meaning of the marking code 'L21' on BAS31,215?

'L21' is the Nexperia device identification code printed on the top surface of the SOT23 package, uniquely identifying the BAS31 variant. It appears alongside country-of-origin indicators (e.g., 'p' for Hong Kong, 't' for Malaysia) and is used for traceability and counterfeit detection in automated optical inspection systems.