MMBF5485 vs 2N7002BKS,115: Component Comparison for Power Electronics Design
Quick verdict
For RF switching and low-current, high-frequency analog applications, the MMBF5485 excels due to its JFET technology, low noise figure, and 400 MHz frequency rating. Conversely, for general-purpose low-voltage digital switching, load switching, or level shifting in power or logic circuits, the 2N7002BKS,115 offers superior current handling, logic-level gate drive, and ruggedness, making it the better choice for embedded and automotive-grade digital switching applications.
Spec comparison table
| Spec | MMBF5485 | 2N7002BKS,115 | Notes |
|---|---|---|---|
| Configuration | N-Channel JFET | 2 x N-Channel MOSFET (dual) | MOSFETs offer lower gate drive power; JFET has different drive characteristics. |
| Current rating (continuous) | 10 mA | 300 mA (typ) | 2N7002BKS supports 30x higher continuous current for power switching. |
| Peak current | Not specified | 1.2 A | 2N7002BKS can handle transient surges far beyond MMBF5485 capability. |
| Frequency rating | 400 MHz | ≥1 MHz switching frequency (min) | MMBF5485 is suitable for RF applications; 2N7002BKS is for low-frequency switching. |
| Voltage rating (max) | 25 V | 60 V | 2N7002BKS supports over twice the voltage, enabling higher-voltage switching. |
| Voltage test rating | 15 V | Not specified | Test rating less relevant than max voltage rating. |
| Drain-Source On Resistance (Rds(on)) | Not specified | Typ 1.6 Ω @10V/500mA, Max 3 Ω @5V/50mA | 2N7002BKS has measurable Rds(on) specs for conduction loss; MMBF5485 data unavailable. |
| Gate threshold voltage (Vgs_th) | Not specified | Typ 1.6 V, Min 1.1 V, Max 2.1 V | 2N7002BKS is logic-level (1.6 V typical threshold), suitable for 3.3 V and 5 V logic. |
| Gate charge | Not specified | Typ 50 nC, Min 10 nC | 2N7002BKS requires moderate gate charge; MMBF5485 gate drive not specified. |
| Noise figure | 4 dB | Not specified | MMBF5485 optimized for low-noise RF applications. |
| Output power max | Not specified | Not specified | Output power not specified for either; MMBF5485 implied RF output use. |
| Package type | SOT-23-3 (TO-236-3) | 6-TSSOP (SOT-363) dual MOSFET | Different packages; 2N7002BKS is dual transistor, larger footprint. |
| Mounting type | Surface mount | Surface mount | Both SMT, but different footprints and pinouts. |
| Technology | JFET | MOSFET (Metal Oxide) | Fundamental device technology difference affects drive and switching behavior. |
| Power dissipation (typical/max) | Not specified | Typ 295 mW, Max 1040 mW | 2N7002BKS supports significantly higher power dissipation. |
| Thermal resistance (max per transistor) | Not specified | 425 K/W | 2N7002BKS data available; MMBF5485 lacks thermal specs, likely lower due to lower power. |
| Operating temperature range | Not specified | -55 °C to +150 °C | 2N7002BKS is automotive-qualified with wide temperature range. |
| Storage temperature range | Not specified | -65 °C to +150 °C | 2N7002BKS rated for wider storage temperature range. |
| ESD rating | Not specified | 2 kV | 2N7002BKS offers documented ESD protection rating. |
| Switching delays (td_on/off) | Not specified | td_on typ 10 ns, td_off typ 24 ns | 2N7002BKS offers fast switching suitable for digital control. |
| Leakage current (Id) at 25°C | Not specified | Max 1 µA | 2N7002BKS low leakage current at room temp. |
| Leakage current (Id) at 150°C | Not specified | Max 10 µA | 2N7002BKS leakage increases with temperature but remains low. |
| Input capacitance (Ciss) | Not specified | Max 50 pF @ 10 V | 2N7002BKS input capacitance relevant for switching speed and gate driver design. |
| Gate leakage current (Ig) | Not specified | Max 10 µA @ 25°C | 2N7002BKS gate leakage specified; important for low-power gate drive. |
| Grade/Qualification | Not specified | AEC-Q101 Automotive | 2N7002BKS is qualified for automotive use, implying higher reliability. |
Design trade-offs
The MMBF5485 is a JFET transistor designed primarily for RF and low-noise analog applications, with a frequency rating of 400 MHz and a noise figure of 4 dB. Its current handling is limited to 10 mA, making it unsuitable for power switching or load driving. The JFET’s high input impedance reduces loading on preceding stages, beneficial in sensitive analog front-ends. However, the lack of detailed gate charge, switching speed, and Rds(on) data limits its use in digital or power switching circuits.
In contrast, the 2N7002BKS,115 is a dual N-channel MOSFET array with a 60 V rating and 300 mA continuous drain current capability, with 1.2 A peak pulses. Its Rds(on) at typical operating conditions is around 1.6 Ω at 10 V gate drive and 500 mA current, which is relatively high compared to power MOSFETs but sufficient for low-current switching tasks. The logic-level gate threshold (typ 1.6 V) makes it compatible with 3.3 V and 5 V logic without additional drive circuitry.
Thermally, the 2N7002BKS,115 supports a max power dissipation of 1040 mW (max) and is rated for junction temperatures up to 150 °C, making it robust for embedded and automotive applications. The MMBF5485 lacks explicit thermal dissipation specs, but given its 10 mA current limit, it is unlikely to dissipate significant power and thus does not require heavy thermal management.
The 2N7002BKS’s switching times (td_on ~10 ns, td_off ~24 ns) support moderate frequency digital switching, but it’s clearly not designed for RF applications approaching hundreds of MHz. Its input capacitance (50 pF max) and gate charge (typ 50 nC) require consideration in fast switching circuits or low-power gate drive designs.
From a layout perspective, the MMBF5485’s SOT-23-3 package is smaller and simpler, suitable for compact analog front-end designs. The 2N7002BKS’s 6-TSSOP package is larger and includes two MOSFETs, which may be beneficial for dual-switching applications but requires more PCB area.
Cost-wise, the 2N7002BKS,115 targets automotive-grade applications with AEC-Q101 qualification, which generally implies higher cost and traceability. The MMBF5485 is a simpler, lower-cost component for RF analog circuits, but volume pricing should be verified for large runs.
Use-case fit
Choose MMBF5485 when…
- Designing low-noise RF front-end switches or amplifiers requiring a low 4 dB noise figure at frequencies up to 400 MHz.
- Implementing analog switching in circuits where gate drive power must be minimized and signal integrity preserved.
- Working with very low current signals (≤10 mA) that require JFET input characteristics such as high input impedance.
- Space-constrained RF modules where a small SOT-23-3 package is preferred.
- Applications where minimal parasitic capacitances and noise are critical, such as sensor interface circuits.
Choose 2N7002BKS,115 when…
- Switching loads up to 300 mA at voltages up to 60 V in embedded or automotive electronics.
- Implementing logic-level driven digital switches or level shifters compatible with 3.3 V or 5 V logic families.
- Designing circuits that require dual N-channel MOSFETs in one package for complementary or half-bridge configurations.
- Operating in automotive or industrial environments needing AEC-Q101 qualification and extended temperature range (-55 °C to +150 °C).
- Requiring fast switching times (~10 ns turn-on) for moderate-frequency PWM or digital signals.
Drop-in compatibility
These devices are neither pin-compatible nor footprint-compatible