MMBF5485 vs AON7611: Component Comparison for Power Electronics Engineers

Quick verdict

For low-current, high-frequency RF switching or small-signal amplification up to 400 MHz, the JFET-based MMBF5485 is the clear choice due to its low noise figure and suitable frequency response. Conversely, for power switching applications requiring high continuous current (up to 18.5A) and low R_DS(on) with logic-level drive, the AON7611 MOSFET array is the better candidate, offering significantly higher current handling and integrated complementary MOSFETs.

Spec comparison table

SpecMMBF5485AON7611Notes
ConfigurationN-Channel JFETN and P-Channel MOSFET Array (common drain)AON7611 offers complementary pairs, enabling half-bridge or push-pull configurations.
Current rating (continuous)10 mA9 A (N-Channel), 18.5 A (P-Channel)AON7611 supports three orders of magnitude higher current, suited for power applications.
Frequency400 MHzNot specified (power MOSFET)MMBF5485 supports RF frequencies; AON7611 is for DC to low MHz switching, not RF.
GainNot specifiedNot specifiedGain not applicable; MMBF5485 is a JFET, AON7611 is a MOSFET array.
Mounting typeSurface Mount (SOT-23-3)Surface Mount (8-DFN-EP 3x3 mm)Both are SMT, but AON7611 is larger with better thermal dissipation.
Noise figure4 dBNot specifiedMMBF5485 low noise figure suits low-noise RF front-ends; AON7611 not specified for noise.
Output power maxNot specified1.5 WAON7611 can handle higher power dissipation, relevant for power stages.
Package caseTO-236-3 / SC-59 / SOT-23-38-PowerVDFN (3x3 mm)AON7611’s package supports thermal pad for improved heat dissipation.
TechnologyJFETMOSFET (Metal Oxide)JFET better for RF low-noise; MOSFET better for power switching efficiency.
Voltage rated25 V30 VAON7611 offers higher voltage margin.
Voltage test15 VNot specifiedMMBF5485 rated/tested at 15 V; no test voltage listed for AON7611.
FET feature-Logic Level GateAON7611 can be driven directly from 5 V logic; MMBF5485 gate drive is different (JFET).
Gate charge (Q_g max @ V_GS)Not specified10 nC @ 10 VAON7611 has moderate gate charge, relevant for switching losses and gate drive design.
Input capacitance (C_iss max) @ 15 VNot specified170 pFAON7611 input capacitance affects switching speed and gate driver selection.
Operating temperature rangeNot specified-55°C to 150°C (TJ)AON7611 rated for wide junction temperature range, beneficial for power applications.
R_DS(on) max @ I_D, V_GSNot specified50 mΩ @ 4A, 10VAON7611 has known on-resistance for conduction loss calculations.
V_GS(th) max @ I_DNot specified2.5 V @ 250 µAAON7611 threshold voltage suitable for logic-level drive.

Design trade-offs

The MMBF5485 is a low-current N-channel JFET optimized for RF applications up to 400 MHz, with a low noise figure of 4 dB. This makes it suitable for front-end amplification or switching in RF circuits where linearity and noise figure are critical. Its current rating is very low (10 mA), so it cannot be used for power switching or load driving. The SOT-23 package is compact but offers limited thermal dissipation capability. The JFET structure means gate drive considerations differ from MOSFETs: it requires a bias voltage and cannot be driven by logic-level signals directly.

In contrast, the AON7611 is an integrated MOSFET array containing complementary N- and P-channel devices in an 8-pin DFN package with an exposed pad for improved thermal management. It supports up to 18.5 A continuous current with a maximum drain-source voltage of 30 V, suitable for medium-voltage power switching applications. Its logic-level gate feature and 2.5 V threshold voltage enable direct drive from microcontroller GPIOs or logic ICs, simplifying gate drive circuitry. Its gate charge (10 nC at 10 V) and 170 pF input capacitance are moderate and should be accounted for in gate driver design to optimize switching losses and speed.

Thermally, the AON7611 can dissipate up to 1.5 W, making it suitable for power stages with proper PCB thermal design, whereas the MMBF5485 is limited by package and current capability. The MMBF5485’s JFET technology and high-frequency response come at the cost of low current handling and lack of integrated complementary devices.

From a layout perspective, the AON7611’s DFN package requires good thermal via design and careful PCB layout to realize its low R_DS(on) and power dissipation capabilities. The MMBF5485’s SOT-23 footprint is standard and easier for compact low-power RF circuits but offers no thermal pad for heat sinking.

Cost-wise, the MMBF5485 is expected to be lower cost per unit and simpler to source for RF front-end applications, while the AON7611 is more specialized and likely higher cost but justified in power switching use cases.

Use-case fit

Choose MMBF5485 when…

Choose AON7611 when…

Drop-in compatibility

The MMBF5485 and AON7611 are not pin-compatible nor footprint-compatible. MMBF5485 is a three-terminal JFET in a SOT-23-3 package, while AON7611 is an 8-pin DFN with dual complementary MOSFETs and an exposed pad. Substituting one for the other would require significant PCB redesign and circuit-level adjustments, including gate drive, biasing, and thermal management. No direct drop-in replacement is possible.

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