BSS138LT1G-VB - 50V 200mA N-Channel MOSFET | VBsemi
部品番号: BSS138LT1G-VB ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $0.05 | $0.05 |
| 10 | $0.042 | $0.42 |
| 100 | $0.0311 | $3.11 |
| 500 | $0.0265 | $13.25 |
| 1,000 | $0.0228 | $22.80 |
| 3,000 | $0.0195 | $58.50 |
BSS138LT1G-VB 概要
A small-signal MOSFET is a discrete semiconductor switching transistor in the broader hierarchy: MOSFET -> field-effect transistor -> transistor -> discrete semiconductor. Unlike bipolar junction transistors, MOSFETs are voltage-controlled devices with essentially zero DC gate current, making them ideal for interfacing microcontroller GPIO outputs to loads. The BSS138 family is specifically a logic-level type, meaning its gate threshold is low enough for direct drive from 3.3 V and 5 V logic outputs.
Key features include a low gate threshold voltage suited to logic-level drive, a compact SOT-23 footprint that minimizes board area, surface-mount construction for automated assembly, and RoHS-compliant lead-free construction. The device switches low-current loads such as relay coils, LED strings, level-shifters, and power-management rails in portable products.
Architecturally, the BSS138LT1G-VB uses a lateral DMOS cell structure optimized for low-voltage, low-current switching rather than high-power conduction. Its small die keeps input capacitance low, enabling fast switching with modest gate drive, while the 50 V drain rating provides margin on 12 V and 24 V rails.
Typical applications include DC-DC converter auxiliary switches, load switches in battery-powered products, level-shifting between 5 V and 3.3 V logic domains, and low-side switching of relays and LEDs in cellular phones, printers, PCMCIA cards, and computers - the same application space targeted by the onsemi BSS138LT series.
When designing, keep continuous drain current well below the 200 mA rating at elevated ambient temperature, and add a gate series resistor (typically 100 ohm to 1 kohm) to damp ringing when driven from fast logic outputs.
This page synthesizes distributor pricing from LCSC, drop-in alternatives, pinout, and practical design notes not consolidated in the manufacturer datasheet.
ドロップイン代替品: BSS138LT1G-VB — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: BSS138LT1G-VB （同一形状・フットプリント） — 相違点: Package, Manufacturer, RoHS Status, Transistor Type.
クイック比較ツール — 並列比較する代替部品を選択:
BSS138LT1G
✅ ドロップイン✓ 在庫あり
$0.08 / 個
データシートを見る →BSS138W
✅ ドロップイン📋 参考代替品（カタログ未掲載）
BSS138NH6327XTSA2
✅ ドロップイン✓ 在庫あり
$0.15 / 個
データシートを見る →2N7002LT1G
✅ ドロップイン✓ 在庫あり
$0.02 / 個
データシートを見る →NTR4003
✅ ドロップイン📋 参考代替品（カタログ未掲載）
BSS138LT1G-VB 最大定格＆電気的特性
| トランジスタタイプ | N-Channel Enhancement Mode MOSFET |
| Drain-Source Voltage (Vdss) | 50 V |
| Continuous Drain Current (Id) | 200 mA (Ta) |
| Power Dissipation (Pd) | 225 mW (Ta) |
| 実装タイプ | Surface Mount |
| パッケージ | SOT-23-3 (TO-236) |
| Configuration | Single FET |
| RoHS ステータス | Compliant |
| Manufacturer | VBsemi Elec |
| Equivalent To | onsemi BSS138LT1G |
BSS138LT1G-VB ピン構成
| ピン 1 | G — Gate - logic-level control input |
| ピン 2 | S — Source - connected to ground in low-side configurations |
| ピン 3 | D — Drain - connects to the switched load |
主な用途
BSS138LT1G-VB の用途: 6 件s: Low-Side Load Switching in Battery-Powered Products, Logic-Level Translation (5V <-> 3.3V), DC-DC Converter Auxiliary Switching, Relay and Solenoid Low-Side Drivers, LED Indicators and Backlight Strings, Power Management in Portable and Handheld Products.
Low-Side Load Switching in Battery-Powered Products
The BSS138LT1G-VB fits battery-powered load switching because its logic-level gate threshold turns on fully from a single lithium cell or 3.3 V regulator output, while the 50 V drain rating gives wide margin on 12 V rails. Used as a low-side switch, the source ties to ground and the load connects between the supply and the drain; a 100 kohm gate-to-source pulldown keeps the FET off during MCU reset. Its 200 mA continuous rating covers LEDs, buzzers, small relays, and sensor rails. Because the gate draws no DC current, the switch adds essentially zero quiescent drain - a key benefit for always-on battery products, though switching speed should be limited by a series gate resistor to control inrush and ringing.
おすすめ
Logic-Level Translation (5V <-> 3.3V)
For open-drain buses such as I2C, the BSS138LT1G-VB is the canonical bidirectional level shifter: the gate ties to the low-voltage rail (3.3 V), the source to the 3.3 V pull-up line, and the drain to the 5 V pull-up line. When neither side drives, the body diode conducts and both lines settle at the lower rail; a low input then pulls the opposite side down through the channel. The MOSFET's low threshold guarantees full enhancement at 3.3 V gate bias, and its low gate charge minimizes capacitive loading on the bus. Pull-up resistors of 2.2 kohm to 10 kohm set rise times; the 200 mA rating vastly exceeds I2C sink currents, giving large reliability margin.
おすすめ
DC-DC Converter Auxiliary Switching
The BSS138LT family is specified by onsemi for DC-DC converter applications, and the VBsemi equivalent inherits that role. Typical uses include switching the enable or sync input of a converter, gating a bias rail before the main switch, or acting as a small synchronous element in low-current buck circuits. The device's low input capacitance permits direct drive from PWM controller logic outputs with fast transitions and minimal drive loss, and the 50 V rating safely covers 24 V input topologies with transient margin. Designers should verify that average current including inductor ripple stays below 200 mA and that the 225 mW dissipation limit is respected at the converter's maximum ambient temperature.
おすすめ
Relay and Solenoid Low-Side Drivers
Small signal relays in telecom, test equipment, and appliance control boards typically draw 20 mA to 150 mA coil currents at 5 V to 24 V - squarely within the BSS138LT1G-VB's 200 mA and 50 V envelope. The FET is wired low-side with the coil between the supply and the drain; a flyback diode across the coil clamps the inductive kick that would otherwise exceed the drain rating, and a 1 kohm gate resistor isolates the MCU pin from gate ringing. Its logic-level gate means no driver stage is needed. For larger solenoids, step up to a power MOSFET package such as SOT-223 or DPAK, since 225 mW dissipation bounds this device's continuous duty.
おすすめ
LED Indicators and Backlight Strings
Low-current LED indicators and small backlight strings are ideal loads for the BSS138LT1G-VB in low-side drive configuration. A series resistor sets LED current; the MOSFET switches the cathode side, so either GPIO polarity or PWM dimming is trivially implemented with logic-level drive. The 50 V rating allows series LED chains well beyond 5 V rails, and the 200 mA current limit suits indicator clusters and small 0402/0603 LED arrays. Because PWM dimming toggles the gate capacitively, keep the series gate resistance near 100 ohm for crisp edges at kilohertz PWM frequencies. Power dissipation in the FET is minimal since the LED resistor, not the switch, drops the load voltage.
おすすめ
Power Management in Portable and Handheld Products
onsemi targets the BSS138L at power management in portable and battery-powered products such as computers, printers, PCMCIA cards, and cellular and cordless telephones; the BSS138LT1G-VB serves the same design space at lower cost. Typical roles include gating peripheral power rails under software control, switching between battery and USB power paths at low current, and discharging output capacitors during shutdown. The SOT-23 footprint occupies under 3 mm by 3 mm of board area, critical in wearables and phone-style layouts. Designers should confirm leakage specifications for rail-keeping applications and verify the gate pulldown keeps the switch firmly off in deep-sleep states where GPIO floats.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: BSS138LT1G-VB — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | BSS138LT1G | BSS138W | BSS138 | 2N7002LT1G | NTR4003 |
|---|---|---|---|---|---|---|
| Package | SOT-23-3 (TO-236) | SOT-23-3 (TO-236) - same | SOT-23-3 (TO-236) - same | SOT-23-3 (TO-236) - same | SOT-23-3 (TO-236) - same | SOT-23-3 (TO-236) - same |
| Brand | VBsemi Elec | onsemi | onsemi | NXP Semiconductors | onsemi | onsemi |
| Gate Threshold (Logic Level) | Low (logic-level) | Low (logic-level) | Low (logic-level) | Low (logic-level) | Higher threshold - not ideal at 3.3 V | Low (logic-level) |
| Pinout (SOT-23) | 1=G, 2=S, 3=D | 1=G, 2=S, 3=D | 1=G, 2=S, 3=D | 1=G, 2=S, 3=D | 1=G, 2=S, 3=D | 1=G, 2=S, 3=D |
主な差別化要因
- Significantly lower unit cost than the original （vs BSS138LT1G)
- True logic-level threshold for 3.3 V drive （vs 2N7002LT1G)
- Identical footprint to the entire BSS138/2N7002 SOT-23 ecosystem （vs BSS138W)
設計ノート
The 200 mA rating is specified at 25 C ambient; dissipation must be derated above that temperature because total package power is capped at 225 mW at Ta. Estimated: at 50 C ambient with a typical SOT-23 derating near 1.8 mW/C, allowable dissipation falls to roughly 190 mW - keep continuous load current and RDS(on) losses well under this margin. Inductive loads without a flyback diode can spike the drain past 50 V and destroy the device; always clamp coils.
Place the SOT-23 with generous copper on the drain pad if switching near the 200 mA limit, as the small pads are the primary heat path. Keep the gate trace short and add a 100 kohm gate-to-source pulldown so the FET stays off when the MCU is in reset or the GPIO is high-impedance. A series gate resistor of 100 ohm to 1 kohm damps ringing when driven from fast logic, at a small cost in switching speed - negligible for load-switch duty cycles.
When using the BSS138LT1G-VB as an I2C or bidirectional level shifter, the MOSFET's body diode and gate-capacitance determine bus rise/fall behavior. Choose pull-up resistors (typically 2.2 kohm to 10 kohm) that meet the bus rise-time requirement at the target bus speed; a 3.3 V gate bias fully enhances the channel so the low-level voltage is set by RDS(on) times sink current, which is only a few millivolts at I2C currents. Verify threshold distribution at your actual gate voltage from the VBsemi datasheet.
コンプライアンス情報
RoHS compliance inferred from the G suffix convention of the emulated BSS138LT1G and current VBsemi production standards. REACH, halogen-free, and conflict-minerals status must be confirmed with VBsemi documentation.
