onsemi 1SMB5947BT3

Overview

1SMB5947BT3 from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 82 V (±5%), maximum Zener impedance of 4.6 Ω at 160 mA test current, and reverse leakage current ≤0.25 μA at 62.2 V. It operates across −65 °C to +150 °C and is used for overvoltage protection in DC power rails and voltage reference circuits in industrial power supplies.

For engineers reviewing the 1SMB5947BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 82 V regulation tolerance, 3 W steady-state power dissipation at 75 °C lead temperature, low dynamic impedance, AEC−Q101 qualification status, and SMB package compatibility with automated SMT assembly.

Technical Context

This device functions as a precision voltage clamp in unidirectional DC protection circuits, leveraging its tightly controlled 82 V Zener breakdown with ±5% tolerance and low temperature coefficient above 6 V. Its 4.6 Ω Zener impedance at 160 mA ensures stable regulation under moderate load transients.

The SMB (Case 403A) package provides thermal resistance of 40 °C/W junction-to-lead and 226 °C/W junction-to-ambient (at 25 °C), enabling reliable 3 W operation when mounted on FR-4 PCBs with recommended footprint. Cathode polarity is marked by a band, and the device meets UL 94 V-0 flammability rating.

Key Specifications

Pinout & Package

The 1SMB5947BT3 is housed in an SMB (Case 403A) plastic surface-mount package with cathode indicated by a polarity band. The package features modified L-bend leads for enhanced pad contact area and is rated UL 94 V-0.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener voltage regulation applications.

Compared with 1SMB5947BT3, 1N5375B offers higher power but sacrifices SMT compatibility and low-impedance regulation, while SZ1SMB5947BT3G adds automotive-grade process controls without altering electrical behavior-making it the drop-in qualified variant for production-critical deployments.

Availability

1SMB5947BT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, telecom infrastructure, and renewable energy charge controllers requiring stable component supply and long-term obsolescence management.

Supply support for 1SMB5947BT3 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The 1SMB5947BT3 belongs to the 1SMB59xxBT3 series of 3 W surface-mount Zener regulators, engineered for high-reliability voltage clamping and reference applications in space-constrained, thermally demanding environments.

FAQ

What is the Zener voltage tolerance of the 1SMB5947BT3?

The 1SMB5947BT3 has a Zener voltage tolerance of ±5%, with a nominal value of 82 V, a minimum of 77.9 V, and a maximum of 86.1 V at 160 mA test current. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet (Rev. 7, November 2011). The 1SMB5947BT3 maintains this specification across its full operating temperature range.

Is the 1SMB5947BT3 RoHS-compliant and lead-free?

Yes, the 1SMB5947BT3 is Pb-free and RoHS-compliant, as indicated by the "G" suffix in its ordering designation and explicitly stated in the Mechanical Characteristics section. The device uses void-free transfer-molded plastic packaging and meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements for reflow soldering at 260 °C for 10 seconds. The 1SMB5947BT3 complies with global environmental regulations without compromising solderability or thermal performance.

What is the maximum power dissipation of the 1SMB5947BT3 at ambient temperature?

The 1SMB5947BT3 delivers 550 mW maximum steady-state power dissipation at T_A = 25 °C, derating linearly at 4.4 mW/°C above that temperature. At T_L = 75 °C (lead temperature), it achieves its full 3.0 W rating-enabled by the SMB package's 40 °C/W junction-to-lead thermal resistance. This dual-rating structure means the 1SMB5947BT3 must be mounted on a PCB with adequate copper pour or thermal vias to sustain 3 W continuously in real-world conditions.

Does the 1SMB5947BT3 meet AEC−Q101 reliability standards?

No-the base 1SMB5947BT3 is not AEC−Q101 qualified. Only the SZ-prefixed variant, SZ1SMB5947BT3G, carries AEC−Q101 qualification and PPAP capability as noted in the Features section of the datasheet. The 1SMB5947BT3 shares identical electrical and mechanical specifications but lacks the automotive-grade process controls, lot traceability, and stress-test validation required for automotive production. For automotive use, the 1SMB5947BT3 must be replaced with SZ1SMB5947BT3G.

What is the reverse leakage current specification for the 1SMB5947BT3?

The 1SMB5947BT3 exhibits a maximum reverse leakage current (I_R) of 0.25 μA at V_R = 62.2 V, per the Electrical Characteristics table. This ultra-low leakage ensures minimal parasitic loading in high-impedance reference divider networks and preserves accuracy in precision voltage monitoring circuits. The 1SMB5947BT3 maintains this spec across its full storage and operating temperature range (−65 °C to +150 °C), supporting stable performance in harsh thermal environments.