Diodes Incorporated BSS138DWK-7

Overview

BSS138DWK-7 from Diodes Incorporated is a dual N-channel enhancement-mode MOSFET in SOT363 package, rated for 50V V_DSS, 2.6Ω R_DS(ON) at V_GS = 10V, and 310mA continuous drain current at +25°C. It features ESD-protected gates, low input capacitance (22pF C_iss), and fast switching (t_F = 7.3ns), deployed as a compact load switch in portable power management circuits.

For engineers reviewing the BSS138DWK-7 datasheet, BSS138DWK-7 pinout, BSS138DWK-7 application, or BSS138DWK-7 equivalent, key selection criteria include gate threshold voltage (0.5–1.5V), R_DS(ON) vs. V_GS performance at 2.5V/4.5V/10V, thermal resistance (R_θJA = 371°C/W on FR-4), and dual-channel isolation for independent load control.

Technical Context

This dual MOSFET integrates two matched N-channel devices sharing no internal connection-each channel operates independently with separate source, drain, and gate terminals. Its low V_GS(TH) enables direct drive from 2.5V and 3.3V logic, while tight R_DS(ON) tolerance (±20% typical) ensures consistent current handling across channels.

The device uses a planar silicon process with optimized gate oxide thickness to balance low gate charge (Q_g = 0.8nC at V_GS = 10V) and robust ±20V gate-source rating. Its 22pF input capacitance and 4pF Crss support high-frequency switching up to several MHz in DC-DC enable paths and USB port protection.

Key Specifications

Pinout & Package

Package: SOT363 - 6-pin, surface-mount, dual-channel discrete package with 0.65mm pitch, 2.15mm × 2.10mm footprint, and 0.30mm nominal height. Molded green compound, matte tin terminations, JEDEC-compliant moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DMN2041LSD-13 and NTJD4152PZ-1, BSS138DWK-7 uniquely balances 50V rating, 2.5V logic compatibility, ESD protection, and industrial temperature range in the smallest SOT363 footprint-making it optimal for compact, robust, multi-rail load switching where reliability and layout density are critical.

Availability

BSS138DWK-7 is available at Aetrix Electronics and suitable for USB power management, IoT sensor node power gating, and automotive body control modules requiring stable component supply, full RoHS/Green compliance, and traceable sourcing.

Supply support for BSS138DWK-7 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and automotive markets.

The BSS138DWK belongs to Diodes' "Small Signal MOSFET" product line, engineered specifically for space-constrained, low-voltage load switching applications demanding low gate charge, tight parametric matching, and robust ESD immunity.

FAQ

Is BSS138DWK-7 suitable for bidirectional current flow?

No. While each channel's body diode conducts from source to drain, the device is designed for unidirectional load switching with source tied to ground or common reference. Bidirectional blocking requires external circuitry or complementary P/N pairs. The datasheet specifies only forward diode conduction (V_SD = 0.8–1.2V) and does not characterize reverse conduction capability.

What is the maximum safe operating frequency for PWM switching with BSS138DWK-7?

Based on t_F = 7.3ns and t_R = 1.2ns, the device supports clean switching up to ~10MHz in low-duty-cycle, low-current (<100mA) applications. For sustained 50% duty-cycle PWM at >1MHz, thermal limits (P_D = 0.33W) and gate drive strength must be validated per layout-typical use remains below 1MHz in load-switching roles.

Does BSS138DWK-7 require external gate resistors for MCU GPIO driving?

Not strictly required for static switching, but recommended for EMI control and ringing suppression. With C_iss = 22pF and typical MCU GPIO R_OUT ≈ 20–50Ω, adding a 10–47Ω series resistor near the gate reduces overshoot and improves edge monotonicity-especially critical when routing traces >2cm or sharing ground planes with noise-sensitive analog sections.

How does R_DS(ON) change with temperature in real-world operation?

R_DS(ON) increases linearly with junction temperature: normalized to 1.0× at 25°C, it reaches ~1.4× at 125°C and ~1.6× at 150°C (per Figure 6). At 100°C junction, R_DS(ON) rises to ~3.6Ω @ V_GS = 4.5V-designers must derate current accordingly to avoid thermal runaway in enclosed, high-ambient environments.