STMicroelectronics STK820

Overview

STK820 from STMicroelectronics is an N-channel 25 V PolarPAK® Power MOSFET optimized for high-efficiency switching applications, featuring R_DS(on) = 0.0058 Ω at V_GS = 10 V, 21 A continuous drain current at T_A = 25 °C, and ultra-low junction-to-case thermal resistance (1.0 °C/W top-side). It enables compact, high-current power stages in DC-DC converters and motor drivers.

For engineers reviewing the STK820 datasheet, STK820 pinout, STK820 application, or STK820 equivalent, this page delivers verified electrical ratings, thermal performance data, PolarPAK® package layout guidance, and real-world switching behavior under 4.5 V and 10 V gate drive conditions.

Technical Context

The STK820 employs ST's "single feature size" strip-based process to achieve high cell density and low on-resistance. Its double-sided cooling PolarPAK® package allows heat extraction from both top (drain) and bottom (source) surfaces, enabling higher sustained current than comparable SO-8 or DPAK devices.

It exhibits low dynamic parameters: C_iss = 1425 pF, Q_g = 9.5 nC, and fast switching with t_d(on) = 15 ns and t_f = 4 ns under 4.7 Ω gate resistance - critical for high-frequency synchronous buck converters and Class-D audio output stages.

Key Specifications

Pinout & Package

PolarPAK® is a surface-mount, double-sided cooling package with exposed top-side drain and bottom-side source terminals. The die is fully encapsulated with matte tin finish, compliant with RoHS (2002/95/EC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel power MOSFET applications.

Compared with Si7157DP and BSC010N03LS, the STK820 uniquely balances ultra-low R_DS(on), sub-10 nC Q_g, and dual-sided thermal management - making it optimal for space-constrained, high-current, high-frequency switching where thermal headroom is limited.

Availability

STK820 is available at Aetrix Electronics and suitable for DC-DC converters, motor drives, Class-D amplifiers, and hot-swap controllers requiring stable component supply despite its obsolete status - supported via legacy inventory and cross-qualified sourcing.

Supply support for STK820 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.

The STK820 belongs to ST's PolarPAK® Power MOSFET product line, engineered specifically for high-current, high-efficiency switching in thermally constrained environments - emphasizing low R_DS(on), low thermal resistance, and robust avalanche performance.

FAQ

Is the STK820 still in active production?

No - STMicroelectronics has marked STK820 as obsolete per its February 2008 datasheet revision history. However, Aetrix Electronics maintains legacy stock and supports continuity through qualified alternate sourcing and obsolescence mitigation programs for long-lifecycle industrial programs.

Can the STK820 be driven directly by a 3.3 V microcontroller GPIO?

Yes - its gate threshold voltage (V_GS(th)) ranges from 1.0 V to 2.5 V, and R_DS(on) remains ≤0.008 Ω at V_GS = 4.5 V. For reliable 21 A switching, a dedicated gate driver is recommended to manage 9.5 nC charge and minimize rise/fall times.

What is the maximum safe operating area (SOA) limitation at 100 °C ambient?

At T_A = 100 °C, the continuous drain current is derated to 13 A (per Table 2), and total power dissipation drops to 2.5 W due to the 0.0416 W/°C derating factor. The SOA curve (Figure 2) confirms safe operation up to 25 V × 13 A in linear mode for pulse widths <10 ms.

How does the PolarPAK® package differ from standard SO-8 in thermal performance?

PolarPAK® provides two independent thermal paths: top-side drain (R_thj-c = 1.0 °C/W) and bottom-side source (R_thj-c = 2.8–3.4 °C/W), whereas SO-8 relies solely on bottom-side conduction (R_thj-c ≈ 3.5–4.5 °C/W). This dual-path design lowers total junction-to-ambient resistance by up to 40% on identical PCB layouts.