BSS123IXTSA1 - 100V N-Ch 190mA OptiMOS MOSFET | Infineon
MPN: BSS123IXTSA1 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.35 | $3.50 |
| 100 | $0.22 | $22.00 |
| 500 | $0.16 | $80.00 |
| 1,000 | $0.13 | $130.00 |
| 3,000 | $0.11 | $330.00 |
BSS123IXTSA1 Overview
A small-signal MOSFET is a discrete field-effect transistor designed for low-current switching, level shifting, and analog signal routing rather than for power conversion. Within the broader semiconductor taxonomy, the BSS123I belongs to the MOSFET family (metal-oxide-semiconductor field-effect transistor), which itself sits under discrete semiconductors and power-management switching devices. Small-signal N-channel MOSFETs like this one are commonly used as low-side switches, in driver stages, in DC-DC converter peripheral circuitry, and in load- and interface-switching applications where the load current does not exceed a few hundred milliamps.
Key electrical features of the BSS123IXTSA1 include a 100 V drain-source breakdown voltage, a typical on-resistance (RDS(on)) of about 2.4 ohm at VGS=10 V (with a maximum of 6 ohm per the family datasheet), and a low gate threshold voltage that allows direct 3.3 V or 5 V logic-level drive. The device is housed in the industry-standard SOT-23-3 footprint, providing excellent thermal coupling to the PCB copper pour and enabling reflow-compatible surface-mount assembly.
The OptiMOS process technology used in this part delivers a clean, well-controlled transfer characteristic and tight threshold-voltage distribution, which simplifies parallel-device use and ensures predictable switching behavior across temperature. The combination of low gate charge, low input capacitance, and fast switching edges makes the BSS123IXTSA1 a practical choice for high-frequency small-signal paths.
Typical applications include low-side switching in battery management and power-path controllers, level-shifters between 1.8 V/3.3 V logic and 12 V/24 V loads, signal multiplexing in instrumentation and test equipment, and discrete driver stages for relays, LEDs, and small solenoids. The 100 V rating provides ample headroom for 12 V and 24 V industrial buses.
When designing with the BSS123IXTSA1, observe the 500 mW power dissipation limit of the SOT-23 package and derate appropriately above 25C ambient. For pulse loads, the safe operating area defined in the Infineon datasheet should be respected. Use a gate-source pull-down resistor to prevent inadvertent turn-on during MCU reset.
This page combines verified distributor pricing, drop-in same-brand and cross-brand alternatives, and practical design notes that go beyond the manufacturer datasheet to support component selection, sourcing, and PCB-level integration.
Drop-in alternatives for BSS123IXTSA1 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with BSS123IXTSA1 (same form factor and footprint) β differing in Package, Drain-Source Voltage (VDS), Continuous Drain Current (ID), FET Type, Gate Threshold Voltage (VGS(th)).
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
BSS123I
β Drop-Inπ Reference alternative (not in catalog)
BSS123NH6327XTSA1
β Drop-Inβ In Stock
$0.085 / Unit
View Datasheet βVB1106K
β Drop-Inπ Reference alternative (not in catalog)
2N7002L
β Drop-Inβ In Stock
$0.028 / Unit
View Datasheet β2N7002L
β Drop-Inβ In Stock
$0.028 / Unit
View Datasheet βBSS123IXTSA1 Maximum Ratings & Electrical Characteristics
| Transistor Type | N-Channel MOSFET |
| Technology | OptiMOS Small-Signal |
| Drain-Source Voltage (VDS) | 100 V |
| Continuous Drain Current (ID) at TA=25C | 190 mA |
| Power Dissipation (PD) at TA=25C | 500 mW |
| RDS(on) (typical, VGS=10 V) | 2.4 ohm |
| RDS(on) (max per family datasheet) | 6 ohm |
| Package | PG-SOT-23-3 (SOT-23-3) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -55C to +150C (per family datasheet) |
| Qualification | Industrial |
| Configuration | Single N-Channel |
| Lead-Free / RoHS | Yes (per distributor listing) |
| Gate Drive Logic Level | Logic-level compatible |
BSS123IXTSA1 Pin Configuration
| Pin 1 | Gate β MOSFET gate control input; logic-level compatible |
| Pin 2 | Source β MOSFET source terminal; typically tied to circuit ground in low-side switching |
| Pin 3 | Drain β MOSFET drain terminal; switches the load |
Typical Applications
BSS123IXTSA1 is suitable for 6 applications: Low-Side Switching in Battery Management, Logic-Level Level Shifter 3.3V to 12V, Signal Multiplexing and Analog Switching, LED Driver and Indicator Switch, Relay and Solenoid Driver Stage, IoT Sensor Node Load Switching.
Low-Side Switching in Battery Management
The BSS123IXTSA1 serves as a low-side switch in battery management and protection circuits, where its 100 V VDS rating easily covers 4S to 10S lithium packs (up to 42 V nominal). With 190 mA continuous drain current and 500 mW power dissipation, it can drive fuel-gauge enable lines, LED status indicators, and auxiliary load-disconnect FETs. The 2.4 ohm typical RDS(on) at VGS=10 V keeps conduction loss modest. Designers must observe the SOT-23-3 thermal envelope and use adequate copper pour to keep junction temperature within the -55C to +150C operating range during high-duty-cycle switching.
Recommended
Logic-Level Level Shifter 3.3V to 12V
Used as a low-side level translator, the BSS123IXTSA1 accepts 3.3 V GPIO drive from an MCU and switches 12 V loads on its drain. Its logic-level threshold permits direct GPIO connection without a gate driver. The 100 V VDS provides ample margin for 24 V industrial rails. A 100 kohm gate-source pull-down resistor prevents floating-gate turn-on during MCU reset, while the 500 mW dissipation limit keeps the SOT-23-3 package within thermal limits for typical pulse-driven signal lines and small relay coils.
Recommended
Signal Multiplexing and Analog Switching
In test and instrumentation equipment, the BSS123IXTSA1 multiplexes low-current analog signals between ADC channels and sensor front-ends. Its low gate charge and fast switching edges support multiplex rates well into the kHz range. The 100 V rating allows switching of higher-voltage transducer outputs when needed. Designers should note that the drain-source capacitance forms an RC network with source impedance, which may introduce settling-time artifacts in high-precision measurement paths.
Recommended
LED Driver and Indicator Switch
The BSS123IXTSA1 efficiently PWM-drives indicator LEDs, status lamps, and optocoupler input diodes from a microcontroller GPIO. At 190 mA continuous current, it handles most discrete indicator LEDs and optocoupler inputs directly. The 100 V VDS allows driving high-side LED strings in industrial HMI panels. For higher currents or multi-channel LED matrices, designers should consider dedicated LED drivers such as the BTS3011TEATMA1 to offload thermal stress from the small SOT-23-3 footprint.
Recommended
Relay and Solenoid Driver Stage
The BSS123IXTSA1 drives small signal relays and solenoids in industrial control and white-goods applications, switching inductive loads on its drain. The 100 V VDS withstands flyback spikes when paired with a flyback diode across the coil. Continuous current of 190 mA covers most sub-miniature signal relays; larger contactors require a higher-current MOSFET or a dedicated smart switch such as the BTS500801TEAAUMA1. Place a TVS or snubber across the drain-source for unclamped inductive loads.
Recommended
IoT Sensor Node Load Switching
In battery-powered IoT sensor nodes, the BSS123IXTSA1 enables duty-cycled power to sub-circuits such as environmental sensors, radios, and ADCs, extending battery life through sub-microamp off-state leakage. Its small SOT-23-3 footprint fits space-constrained wearable and smart-home designs. The 100 V VDS rating supports USB-C VBUS hot-swap protection up to 20 V. Pair with a low-quiescent LDO such as the TLE42662GSV33HTMA2 to maintain overall node sleep current below 10 uA.
Recommended
Recommended Products Summary
Engineering reference data for BSS123IXTSA1 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BSS123I | BSS123 | VB1106K | 2N7002 |
|---|---|---|---|---|---|
| Package | SOT-23-3 (PG-SOT-23-3) | SOT-23-3 - same | SOT-23-3 - same | SOT-23-3 - same | SOT-23-3 - same |
| Drain-Source Voltage (VDS) | 100 V | 100 V | 100 V | 100 V (per cross-reference data) | 60 V |
Key Differentiators
- Higher VDS rating (100 V) versus 2N7002 (60 V) (vs 2N7002 (onsemi))
- OptiMOS process technology (vs BSS123 (legacy Infineon))
- Higher power dissipation (500 mW vs 350 mW for 2N7002) (vs 2N7002 (onsemi))
Design Notes
The BSS123IXTSA1 has a power dissipation limit of 500 mW at TA=25C in the SOT-23-3 package. With a typical theta_JA around 357 C/W on a standard JEDEC 1sq-in 1oz copper test board, the device derates linearly to near 0 mW at 150C junction temperature. For continuous loads above 100 mA, attach the SOT-23-3 drain pad (pin 3) to at least 100 sq mm of 1 oz copper pour on both PCB layers to reduce theta_JA below 200 C/W. Estimated: at 100 mA continuous and VDS=10 V, conduction loss is approximately 0.24 W, requiring a heatsink copper pour of 200 sq mm to keep Tj below 100C at 50C ambient.
Use the standard SOT-23-3 land pattern (IPC-7351 nominal footprint) for drop-in compatibility with 2N7002, BSS138, and similar parts. Place a 100 kohm gate-source pull-down resistor within 2 mm of the gate pin to prevent floating-gate turn-on during MCU reset or hot-plug events. Keep the drain trace short and direct to minimize parasitic inductance, especially when switching inductive loads. A small TVS or Schottky flyback diode across the load is recommended for relay or solenoid drive applications.
Do not assume the BSS123IXTSA1 will fully enhance at 2.5 V gate drive - the threshold voltage is typically 1-2 V and RDS(on) is only specified at VGS=10 V. For 3.3 V-only designs, verify that the actual RDS(on) at VGS=3.3 V still meets your load-current budget. Never operate the device above the 100 V VDS rating, even transiently - inductive load spikes can easily exceed VDS and cause avalanche breakdown. For unclamped inductive switching, add a TVS or RC snubber rated below 80% of VDS(max).
Compliance Information
RoHS and lead-free per DigiKey and Mouser distributor listings; REACH and conflict-minerals compliance per Infineon product page. Industrial qualification only - not AEC-Q100 qualified for automotive.
