Diodes Incorporated 1SMB5949B-13

Overview

1SMB5949B-13 from Diodes Incorporated is a 3.0W surface-mount power Zener diode with a nominal zener voltage of 100 V (min 95 V, max 105 V), ±5% tolerance, 250 mA maximum zener test current, and 3100 Ω dynamic impedance at I_ZT. It provides precise voltage regulation in DC power supply rails and overvoltage protection circuits for industrial power converters.

For engineers reviewing the 1SMB5949B-13 datasheet, 1SMB5949B-13 pinout, 1SMB5949B-13 application, or 1SMB5949B-13 equivalent, key selection criteria include zener voltage accuracy, thermal resistance (226 °C/W), ESD robustness (>16 kV HBM), SMB package compatibility, and derating behavior above +25°C ambient.

Technical Context

This Zener diode operates in reverse breakdown to clamp voltage across load circuits, maintaining stable reference or protection thresholds under varying current conditions. Its 3.0 W power rating applies at T_L = +75°C with 40 mW/°C derating, and junction-to-ambient thermal resistance is 226 °C/W on FR-4 PCB per AP02001 layout.

The device exhibits a typical temperature coefficient near +8.5 mV/°C at 100 V (inferred from Figure 2), supports 0.25 µA maximum reverse leakage at 76 V, and delivers 15 A peak pulse current capability per 10×1000 µs waveform (Figure 9), enabling transient suppression in power rail interfaces.

Key Specifications

Pinout & Package

SMB (DO-214AA) package: molded plastic case rated UL 94V-0, copper alloy leadframe with matte tin plating, cathode indicated by band on top surface, weight ≈ 0.096 g. Moisture sensitivity level 1 per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power Zener diode applications.

Compared with 1N5375B and SMBJ100A, the 1SMB5949B-13 uniquely balances SMT manufacturability, ±5% DC regulation accuracy, and 3.0 W continuous dissipation-making it optimal for space-constrained, high-reliability DC rail stabilization rather than surge-only or through-hole use cases.

Availability

1SMB5949B-13 is available at Aetrix Electronics and suitable for industrial power supply protection, PLC input conditioning, telecom line card surge suppression, and test equipment reference calibration requiring stable component supply and RoHS-compliant sourcing.

Supply support for 1SMB5949B-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The 1SMB59xxB series belongs to Diodes' high-power Zener diode product line, engineered specifically for precision voltage regulation and overvoltage protection in industrial, telecom, and automotive power systems where reliability and SMT compatibility are critical.

FAQ

What is the maximum continuous zener current for 1SMB5949B-13 at +75°C?

The device supports 250 mA zener test current (I_ZT) at 25°C, but continuous current must be limited by thermal derating. At T_L = +75°C, its 3.0 W power rating allows up to ~30 mA at 100 V (P = V × I), assuming adequate PCB copper area per AP02001 layout. Exceeding this risks junction overheating beyond 150°C.

Does 1SMB5949B-13 have a specified temperature coefficient?

No explicit temperature coefficient value is listed in the datasheet, but Figure 2 shows typical TC ≈ +8.5 mV/°C for 100 V Zeners. This positive coefficient means V_Z increases ~0.0085 V per °C rise, which must be accounted for in precision reference designs operating across -65°C to +150°C.

Can 1SMB5949B-13 replace a 1N5375B in an existing design?

Electrically, yes - both have 100 V nominal V_Z and ±5% tolerance - but mechanically no: 1SMB5949B-13 uses SMB (DO-214AA) SMT package versus DO-41 through-hole. PCB redesign and reflow validation are required; thermal performance differs due to lower R_θJA (226 vs ~300 °C/W).

Is 1SMB5949B-13 suitable for automotive applications?

It meets AEC-Q200 stress test requirements for passive components (per Diodes' qualification reports), carries RoHS 3 and "Green" certifications, and operates from -65°C to +150°C. However, it is not AEC-Q101 qualified as a discrete semiconductor; use requires validation per vehicle-specific EMC and lifetime reliability standards.