onsemi 1PMT5931BT1G

Overview

1PMT5931BT1G from onsemi is a 3.2 W surface-mount Zener diode in the POWERMITE® (DO−216AA) package, rated for 17.1–18.9 V nominal Zener voltage at 20.8 mA test current, with 13.7 Ω dynamic impedance and 1.0 µA reverse leakage at 14.6 V. It delivers low-profile thermal performance (1.1 mm height, 23 °C/W junction-to-cathode thermal resistance) and is used for precision voltage regulation in space-constrained portable electronics.

For engineers reviewing the 1PMT5931BT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 3.2 W power rating at cathode temperature of 75°C, JEDEC-registered DO−216AA footprint, Pb-free compliance, ESD robustness (>16 kV HBM), and verified Zener voltage tolerance (±5%) across production lots.

Technical Context

The 1PMT5931BT1G operates as a two-terminal voltage reference device, maintaining stable reverse-biased breakdown across load and line variations. Its Zener voltage is specified at IZT = 20.8 mA with ±5% tolerance, and it exhibits a positive temperature coefficient above ~5 V, typical for 18 V-class Zeners.

Thermal design relies on direct cathode tab conduction to PCB copper; R_Jcathode = 23 °C/W enables 3.2 W dissipation only when the cathode (Terminal 1) is thermally anchored per recommended pad layout. The device is not intended for surge clamping but for steady-state regulation under controlled DC bias.

Key Specifications

Pinout & Package

POWERMITE® (DO−216AA) is a 2-terminal surface-mount plastic package with integral heat sink tabs and full metallic bottom. Cathode is Terminal 1 (marked by polarity band); Anode is Terminal 2. Package dimensions: 1.75–2.05 mm × 1.75–2.18 mm × ≤1.1 mm (L×W×H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4746A and SMBJ18A, the 1PMT5931BT1G uniquely combines surface-mount compatibility, 3.2 W continuous dissipation via cathode thermal path, and tight Zener voltage control-making it the only option among the three qualified for compact, thermally managed DC regulation at 18 V.

Availability

1PMT5931BT1G is available at Aetrix Electronics and suitable for smartphone power rails, wearable sensor biasing, industrial PLC I/O modules, and medical portable diagnostic devices requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for 1PMT5931BT1G 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 supplier focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and intelligent edge applications.

The 1PMT5931BT1G belongs to the 1PMT59xxB Series of high-power Zener diodes engineered specifically for space-constrained, thermally demanding portable and industrial systems requiring reliable DC voltage regulation without through-hole mounting.

FAQ

What is the Zener voltage tolerance of the 1PMT5931BT1G?

The 1PMT5931BT1G has a Zener voltage tolerance of ±5% around the nominal 18 V rating, specified as 17.1–18.9 V at I_ZT = 20.8 mA and T_L = 25°C. This tolerance is guaranteed across production lots and does not require binning or post-manufacture screening. The 1PMT5931BT1G achieves this consistency via process-controlled diffusion and laser trimming during wafer fabrication.

Can the 1PMT5931BT1G replace a standard SMA Zener diode?

The 1PMT5931BT1G is not a drop-in replacement for SMA-packaged Zeners due to different footprint and thermal interface requirements. While both offer similar power ratings, the 1PMT5931BT1G uses the smaller DO−216AA outline with cathode-tab thermal anchoring, whereas SMA relies on lead-frame conduction. Replacing an SMA part with 1PMT5931BT1G requires PCB redesign to accommodate the 1.75 × 1.75 mm pad layout and thermal via placement under Terminal 1.

What is the maximum allowable ambient temperature for continuous 3.2 W operation of the 1PMT5931BT1G?

The 1PMT5931BT1G achieves its full 3.2 W rating only when the cathode tab temperature (T_tab) is maintained at 75°C. At higher ambient temperatures, derating applies: power must be reduced linearly above 25°C at 4.0 mW/°C. For example, at T_A = 60°C, maximum dissipation drops to approximately 2.2 W unless additional copper area or forced airflow is applied to maintain T_tab ≤ 75°C.

Does the 1PMT5931BT1G have a specified temperature coefficient?

Yes-the 1PMT5931BT1G exhibits a positive temperature coefficient typical of 18 V Zeners, approximately +0.075 %/°C near 25°C. This value is derived from the slope of V_Z versus junction temperature curves in the datasheet's Figure 6 and confirms stable regulation over −55°C to +150°C operating range. The 1PMT5931BT1G's coefficient remains within industry norms for mid-voltage Zeners and is accounted for in precision reference designs.

Is the 1PMT5931BT1G suitable for surge protection applications?

No-the 1PMT5931BT1G is designed for continuous DC voltage regulation, not transient suppression. Its 3.2 W rating applies only to steady-state conditions with proper thermal management. For surge events, dedicated TVS diodes like SMBJ18A (600 W peak) are required. Using the 1PMT5931BT1G for surge clamping risks catastrophic failure due to insufficient peak power handling and lack of defined clamping voltage specs.