onsemi 1PMT5921BT1G

Overview

1PMT5921BT1G from onsemi is a 3.2 W surface-mount Zener diode in the POWERMITE (DO-216AA) package, with nominal Zener voltage 6.8 V, test current 55.1 mA, and maximum dynamic impedance 2.5 Ω at IZT. It delivers low-profile thermal performance (1.1 mm height, 23 °C/W junction-to-cathode thermal resistance) and is rated for −55 °C to +150 °C operation. Used for voltage regulation and overvoltage protection in space-constrained portable electronics.

For engineers reviewing the 1PMT5921BT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 6.8 V ±5% Zener tolerance, 3.2 W cathode-tab power rating at 75 °C, Class 3 ESD robustness (>16 kV HBM), and DO-216AA footprint compatibility with high-density PCB layouts.

Technical Context

The 1PMT5921BT1G operates as a precision voltage reference and clamping device, leveraging silicon PN-junction Zener breakdown. Its thermal design centers on the cathode tab as primary heat path (R_Jcathode = 23 °C/W), enabling stable regulation under pulsed or continuous DC loads up to 3.2 W when mounted per JEDEC DO-216AA layout guidelines.

Electrical behavior is defined at T_L = 30 °C with V_F ≤ 1.25 V @ 200 mA forward bias. Zener impedance is measured at 60 Hz AC superimposed on DC bias (i_Z(rms) = 0.1 I_Z(dc)), yielding ZZT = 2.5 Ω and ZZK = 200 Ω at specified test currents - critical for low-noise regulation in power supply feedback paths.

Key Specifications

Pinout & Package

Package: POWERMITE (JEDEC DO-216AA), surface-mount plastic case with integral heat sink tabs and full metallic bottom. Cathode indicated by polarity band; anode and cathode terminals are co-planar on the same side of the package.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4734ATR and MMSZ4686T1G, the 1PMT5921BT1G uniquely combines 3.2 W power handling, DO-216AA miniaturization, and cathode-tab thermal management - making it the only option among the three capable of regulating 5 V/600 mA loads in <2 mm Z-height consumer enclosures.

Availability

1PMT5921BT1G is available at Aetrix Electronics and suitable for smartphone power management, USB-C port protection, and wireless headset battery monitoring requiring stable component supply and consistent thermal performance across production volumes.

Supply support for 1PMT5921BT1G 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The 1PMT5920B Series was engineered specifically for high-density, thermally constrained portable electronics - prioritizing low-profile packaging, robust ESD immunity, and stable Zener regulation without external thermal enhancement.

FAQ

What is the Zener voltage tolerance of the 1PMT5921BT1G?

The 1PMT5921BT1G has a Zener voltage range of 6.46 V to 7.14 V at I_ZT = 55.1 mA, corresponding to a nominal 6.8 V with ±5% tolerance. This specification is verified per onsemi's Electrical Characteristics table on page 2 of the October 2024 Rev. 6 datasheet and applies under thermal equilibrium at T_L = 30 °C. The 1PMT5921BT1G maintains this tolerance across its full operating temperature range of −55 °C to +150 °C.

How is thermal management implemented in the 1PMT5921BT1G?

The 1PMT5921BT1G uses its cathode terminal (Pin 1) as the primary thermal path, with a specified junction-to-cathode thermal resistance of 23 °C/W. To achieve the full 3.2 W power rating, the cathode must be soldered to a minimum recommended copper pad per JEDEC DO-216AA layout guidelines. The 1PMT5921BT1G does not rely on ambient convection alone - its integral heat sink tabs and full metallic bottom ensure efficient conduction into the PCB, enabling operation at 75 °C tab temperature.

Is the 1PMT5921BT1G suitable for ESD protection in high-speed interfaces?

Yes - the 1PMT5921BT1G carries a Class 3 Human Body Model ESD rating (>16 kV), validated per ANSI/ESDA/JEDEC JS-001. While not a dedicated TVS diode, its low leakage (<5 μA @ 5.2 V), fast Zener response, and robust junction design make it effective as a secondary clamp in USB-C, I²C, or UART lines where moderate surge energy must be absorbed without signal distortion. The 1PMT5921BT1G is commonly deployed downstream of primary TVS devices in layered protection schemes.

What is the forward voltage drop of the 1PMT5921BT1G?

The forward voltage drop of the 1PMT5921BT1G is specified as ≤1.25 V at I_F = 200 mA, measured at T_L = 30 °C. This parameter is relevant when the device is used in forward-biased configurations (e.g., polarity protection or LED driver biasing). In normal Zener regulation mode, the 1PMT5921BT1G operates in reverse bias; forward conduction is not part of its intended regulation function but remains within safe limits per absolute maximum ratings.

Does the 1PMT5921BT1G require special PCB layout considerations?

Yes - the 1PMT5921BT1G requires adherence to JEDEC DO-216AA footprint and thermal pad guidelines. Specifically, Pin 1 (cathode) must connect to a minimum 2.0 × 2.0 mm exposed copper area with ≥2 thermal vias to internal ground planes to maintain R_θJA ≤ 248 °C/W and sustain 3.2 W operation. The 1PMT5921BT1G datasheet specifies tape-and-reel orientation (cathode toward sprocket holes), and incorrect placement will compromise both thermal performance and functional reliability.