Vishay Siliconix VP0808B-2

Overview

VP0808B from Siliconix is a P-channel enhancement-mode MOSFET designed for high-side switching in low-power analog and digital load control circuits. It features –80 V drain-source breakdown voltage, 2.5 Ω maximum rDS(on) at VGS = –10 V, –3.4 V typical gate threshold voltage, and –0.88 A continuous drain current at TJ = 150°C - enabling robust operation in battery-powered relays and lamp drivers.

For engineers reviewing the VP0808B datasheet, VP0808B pinout, VP0808B application, or VP0808B equivalent, key selection considerations include its TO-205AD (TO-39) metal-can package with case-drain configuration, moderate negative VGS(th) range (–2 to –4.5 V), fast 40 ns turn-off time, low 75 pF input capacitance, and suitability for low-voltage logic-driven switching without buffer stages.

Technical Context

This device operates as a normally-off P-channel power switch requiring negative gate drive relative to source. Its –80 V V(BR)DSS rating supports use in 48 V and lower DC bus systems, while the 2.5 Ω rDS(on) ensures <2.2 mW conduction loss at –0.5 A. The –3.4 V VGS(th) enables direct interface with TTL/CMOS outputs when referenced to a negative rail or level-shifted control.

Thermal performance is defined by RthJA = 156°C/W (TO-205AD), limiting continuous power dissipation to 6.25 W at TA = 25°C. Switching behavior is characterized by 11 ns turn-on delay, 25 ns rise time, 20 ns turn-off delay, and 30 ns fall time under standard test conditions (VDD = –25 V, RL = 50 Ω, ID = –500 mA).

Key Specifications

Pinout & Package

VP0808B is housed in a TO-205AD (TO-39) metal-can package with case-drain configuration - the metal case is electrically connected to the drain terminal and must be isolated from other system potentials unless intentionally used as a heat sink tied to high-side rail.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar P-channel MOSFET switching applications.

Compared with IRF9530 and DMN2004LK, VP0808B uniquely balances –80 V capability, TO-205AD metal-can thermal performance, and logic-compatible gate threshold in a through-hole package - making it optimal for ruggedized, medium-voltage, low-to-moderate current high-side switching where reliability and serviceability matter.

Availability

VP0808B is available at Aetrix Electronics and suitable for relay drivers, battery-powered load switches, and lamp control circuits requiring stable component supply across long-lifecycle industrial and instrumentation programs.

Supply support for VP0808B 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

Siliconix, founded in 1962 and acquired by Vishay in 1998, pioneered high-reliability discrete power semiconductors with emphasis on rugged packaging and stable parametric performance.

The VP0808B belongs to Siliconix's early-generation P-channel MOSFET family engineered for high-side switching in analog control systems, emphasizing predictable threshold behavior, low gate charge, and metal-can thermal robustness over raw current density.

FAQ

What is the maximum continuous drain current rating for VP0808B at 25°C ambient?

The VP0808B has a continuous drain current rating of –0.88 A at TJ = 150°C, which corresponds to approximately –0.53 A at TA = 25°C due to thermal limitations imposed by its RthJA = 156°C/W. This value assumes no heatsinking and free-air convection; actual current capacity increases with improved thermal management. The VP0808B must be operated within these limits to avoid junction overheating and parametric drift.

Is VP0808B suitable for high-side switching with 3.3 V microcontroller GPIOs?

Yes - the VP0808B's –3.4 V typical VGS(th) and –2 to –4.5 V range allow full enhancement when driven by an inverted 3.3 V logic signal (i.e., –3.3 V gate-to-source). A simple NPN inverter or open-drain buffer referenced to the source rail provides adequate gate drive without level-shifting ICs. The VP0808B's low 75 pF Ciss further eases drive requirements.

What does "case drain" mean for VP0808B in the TO-205AD package?

In the VP0808B, the metal case of the TO-205AD (TO-39) package is internally connected to the drain terminal. This means the exposed can is electrically live at drain potential and must be electrically isolated from all other conductive surfaces unless intentionally used as a heatsink tied to the high-side rail. Mounting hardware and PCB layout must account for this inherent drain-to-case short.

How does VP0808B's switching speed compare to modern P-channel MOSFETs?

The VP0808B offers 40 ns total turn-off time, which remains competitive for medium-speed switching applications like relay control and lamp dimming up to 100 kHz. While newer devices achieve sub-10 ns transitions, the VP0808B's 25 ns rise time and 30 ns fall time are well-matched to its 75 pF Ciss and gate drive requirements - ensuring reliable operation without excessive ringing or shoot-through risk in legacy designs.

Can VP0808B replace VP1008B in a design?

No - VP0808B and VP1008B differ in rated V(BR)DSS (–80 V vs. –100 V) and absolute maximum ratings, though both share identical gate threshold, on-resistance, and package. Substituting VP0808B for VP1008B is only safe if the application's worst-case drain-source voltage never exceeds –80 V. Derating margins, transients, and layout parasitics must be re-evaluated before replacement, as VP0808B lacks the extra 20 V safety margin of VP1008B.