Taiwan Semiconductor Corporation PUAD4B

Overview

PUAD4B from Taiwan Semiconductor is a 4A, 100V ultra-fast surface-mount rectifier in ThinDPAK package, featuring 20 ns reverse recovery time, 0.85 V forward voltage at 4A/25°C, and 130 A surge current capability; it serves as a primary output rectifier in high-frequency DC/DC converters.

For engineers reviewing the PUAD4B datasheet, PUAD4B pinout, PUAD4B application, or PUAD4B equivalent, key selection criteria include its 100 V repetitive peak reverse voltage, 3.5 °C/W junction-to-lead thermal resistance, low 77 pF junction capacitance, and suitability for snubber circuits requiring fast switching and low stored charge.

Technical Context

The PUAD4B employs planar silicon technology to achieve ultra-fast recovery with trr ≤ 20 ns under IF = 4.0A, di/dt = 200A/µs, VR = 100V conditions, and delivers Qrr = 42 nC - enabling efficient operation in hard-switched topologies above 100 kHz.

Its single-die ThinDPAK construction provides RθJC = 2.0 °C/W and RθJA = 11.8 °C/W (on 2" × 3" × 0.25" Al heatsink), supporting continuous 4A conduction at TJ ≤ 175°C while maintaining low forward power loss (VF = 0.71 V at 4A/125°C).

Key Specifications

Pinout & Package

Package: ThinDPAK (JEDEC TO-252 variation AE), 3-terminal surface-mount package with exposed drain pad (Pin 2) for thermal and electrical connection; cathode indicated by band on Pin 3 side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-fast rectifier applications.

Compared with STTH4L06D and MBR4100CT, the PUAD4B uniquely balances 100 V rating, 20 ns trr, 175°C operation, and 0.71 V VF at 125°C - making it optimal for thermally constrained, high-frequency industrial power supplies where Schottky leakage or FRD slowness are unacceptable.

Availability

PUAD4B is available at Aetrix Electronics and suitable for high-frequency DC/DC converters, active clamp snubbers, and industrial auxiliary power supplies requiring stable component supply and long-term manufacturability.

Supply support for PUAD4B 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global power electronics markets since 1979.

The PUAD4B belongs to TSC's ultra-fast rectifier product line, engineered specifically for high-efficiency, high-frequency switching power supplies where low Qrr, tight VF consistency, and robust thermal performance are critical.

FAQ

What is the maximum junction temperature rating for PUAD4B?

The PUAD4B has a maximum junction temperature (TJ MAX) of +175°C, verified per absolute maximum ratings table. This allows sustained 4A operation in sealed industrial enclosures without active cooling, provided PCB copper area meets thermal design guidelines. The PUAD4B maintains stable VF and trr performance up to this limit, unlike many Schottky alternatives that degrade above 150°C.

Does PUAD4B have a specified reverse recovery charge (Qrr)?

Yes, the PUAD4B specifies Qrr = 42 nC under conditions IF = 4.0A, di/dt = 200A/µs, VR = 100V. This value is critical for estimating turn-on losses in synchronous rectification circuits and is confirmed in the Electrical Specifications table on page 2 of the official TSC datasheet revision A2302.

What is the marking code printed on the PUAD4B device body?

The PUAD4B is marked with "UAD4B" on its top surface, as stated in the Absolute Maximum Ratings table. This 5-character laser marking distinguishes it from the 200V variant PUAD4D (marked "UAD4D") and confirms the 100V VRRM rating during visual inspection or automated optical sorting.

Is PUAD4B RoHS compliant and halogen-free?

Yes, the PUAD4B is RoHS compliant and halogen-free, as explicitly stated in the FEATURES section of the official TSC documentation. It meets JEDEC J-STD-020 moisture sensitivity level 1 and passes JESD 201 class 2 whisker testing - confirming suitability for lead-free reflow assembly without delamination or tin whisker risk.

What is the thermal resistance from junction to ambient (RθJA) for PUAD4B?

The PUAD4B has RθJA = 11.8 °C/W when mounted on a 2" × 3" × 0.25" aluminum heatsink, per Thermal Performance table. This value assumes full thermal pad soldering and is used for worst-case thermal design; actual RθJA on standard PCBs ranges 45–65 °C/W depending on copper area and layer count.