120A 12S Single ESC
UESC-120-12S-S-B is a 120A 12S single-motor ESC for UAV designers and OEM teams working with high-current brushless powertrains. It supports 6–12S LiPo input, a 120A continuous and 140A peak current rating, and an eight-layer 4oz copper PCB in a 55 × 32 mm board format. Its independent ESC architecture offers flexibility for motor-by-motor placement, power wiring and local cooling. UltroNiu supports product sourcing and custom PCB/PCBA projects.
One high-current ESC channel, independently positioned
Designed for one three-phase brushless motor, the UESC-120-12S-S-B provides a 120A continuous and 140A peak current class for 6–12S UAV power systems. A dedicated ESC per motor lets engineers distribute motor-control hardware within an aircraft rather than concentrate four channels on a single board.
Evaluate the full motor-drive installation
Current requirements, battery-lead length, motor-phase connections, mounting clearance and local airflow must be considered together. The 55 × 32 mm board outline and 21 g net weight help system designers assess the mechanical envelope early.
Component layout and motor-power connections
UESC-120-12S-S-B technical specifications
| Parameter | Specification |
|---|---|
| Model | UESC-120-12S-S-B |
| ESC configuration | Single-motor, three-phase brushless ESC |
| Battery input | 6–12S LiPo |
| Continuous current rating | 120A |
| Peak current rating | 140A |
| Board outline | 55 × 32 mm |
| Net weight | 21 g |
| PCB stack-up | 8 layers, 4oz copper |
| Main MCU | AT32F421K8U7 |
| MCU clock capability | Up to 120 MHz (device maximum) |
| Gate-driver configuration | 3 × SLM21867 |
| Power MOSFET voltage class | 80V |
| Power regulation | DC–DC |
| Filtering components | Ceramic capacitor network |
| Firmware family | AT4G Rev.32.9 series |
| Supported throttle protocols | PWM, OneShot125, OneShot42, Multishot, DShot150, DShot300, DShot600 |
| Motor-control functions | Hardware PWM, Damped Light, active freewheeling |
| Motor phase outputs | A / B / C power pads |
| Control connections | TX / S / G board markings |
Continuous and peak current ratings are product specifications. Installed performance depends on motor loading, wiring, airflow and thermal conditions.
80V MOSFETs and three-phase gate-drive architecture
The specified switching stage uses 80V-class power MOSFETs driven through a three-driver SLM21867 configuration. The AT32F421K8U7 controller manages motor-control functions, while onboard DC–DC power regulation and ceramic filtering support the control electronics.
For a 12S installation, the full-charge battery voltage is only one part of the voltage-stress assessment. Lead inductance, switching transients, input capacitors and power-return layout also affect the electrical margin.
Eight-layer, 4oz copper for the ESC power path
The eight-layer, 4oz copper PCB supports current distribution and thermal conduction across the power and control circuitry. The supplied board construction also specifies resin-filled vias and metallized power-pad edges.
Heat removal is a system-level decision
Actual temperatures depend on switching losses, copper geometry, solder joints, board contact, airflow and mounting. The current class and copper weight should therefore be evaluated against the expected duty cycle rather than treated as a thermal guarantee.
High-current solder connections require appropriate conductor size, mechanical strain relief and reliable insulation.
Battery input, A/B/C motor phases and control markings
Battery input
Positive and negative power pads are used for the 6–12S LiPo supply. Confirm polarity, cable size and input-capacitor requirements during installation.
Motor phase outputs
Three output pads marked A, B and C connect to a single brushless motor. These are motor phases, not three separate ESC channels.
Control markings
The control-side board markings include TX, S and G. Confirm the exact signal, ground and telemetry wiring against the controller and harness used in the final system.
Board size: 55 × 32 mm
Plan the mounting method, vibration isolation, electrical clearances and cable exits using the actual aircraft design. The 21 g board weight is useful when balancing distributed ESC placement across multiple motors.
For system commissioning, confirm control protocol, motor direction, phase wiring and appropriate safe-start behavior before applying propulsion load.
PWM, OneShot, Multishot and DShot interfaces
PWM and OneShot
PWM, OneShot125 and OneShot42 allow the ESC to receive throttle commands from compatible controllers.
Multishot and DShot
Multishot and DShot150/300/600 provide additional command-interface choices for supported flight-controller configurations.
Braking behavior
Damped Light braking and active freewheeling are listed control functions; their behavior depends on the firmware configuration and motor system.
The reference firmware belongs to the AT4G Rev.32.9 series. Use the firmware build matched to the ESC hardware revision when configuring or servicing the unit.
Independent ESC placement in UAV powertrains
Distributed motor-drive installations
A single ESC can be placed according to motor location, harness routing and available cooling, making it relevant to single-motor propulsion modules and multi-motor aircraft using a separate controller per motor.
Engineering selection criteria
Evaluate supply voltage, motor and propeller combination, current profile, electrical transients, ambient conditions, vibration and maintenance access. This helps determine whether the selected ESC architecture fits the platform.
Multilayer PCB manufacturing for UAV power electronics
UltroNiu supports PCB fabrication for UAV power-electronics projects. Manufacturing controls can cover CAM review, stack-up requirements, imaging, copper processing, via metallization and bare-board electrical testing against approved project data.
Assembly, inspection and defined functional checks
ESC PCBA work requires controlled component placement, power-terminal soldering, visual inspection and defined firmware or powered functional checks. For custom hardware programs, assembly and acceptance criteria can be established using approved fabrication files, a BOM and project specifications.
Motor-control and load-testing procedures should reflect the required battery, motor, cooling and operating conditions. These are important inputs to an OEM qualification plan.
From a defined single ESC to custom power electronics
Product supply
Discuss UESC-120-12S-S-B sourcing, quantity, delivery requirements and approved accessory configuration.
Integration review
Share your motor, battery, throttle-control interface, mechanical arrangement and cooling conditions for the target UAV system.
Custom PCB/PCBA
For separate engineering projects, discuss PCB fabrication, component sourcing, assembly and inspection against customer-approved design data.
Technical and sourcing questions about the 120A 12S Single ESC
Is the UESC-120-12S-S-B a single ESC or a 4-in-1 ESC?
It is a single-channel ESC designed to control one brushless motor. The A, B and C output pads are the three motor phases, not separate ESC channels.
What battery input range does this ESC support?
The specified supply range is 6–12S LiPo. Confirm battery wiring, input transients and voltage margin for the intended aircraft.
What are its continuous and peak current ratings?
The product specifications list 120A continuous current and 140A peak current. The applicable load depends on operating conditions and cooling.
What are the board dimensions and weight?
The board outline is 55 × 32 mm and the specified net weight is 21 g.
What PCB construction is used?
The ESC uses an eight-layer PCB with 4oz copper. Its final thermal performance depends on component losses, layout and installation conditions.
Which controller and gate drivers are specified?
The configuration specifies an AT32F421K8U7 MCU and three SLM21867 gate drivers, together with 80V-class MOSFETs.
Which throttle-control protocols are supported?
The listed protocols are PWM, OneShot125, OneShot42, Multishot, DShot150, DShot300 and DShot600.
How are the motor and flight-controller signals connected?
The motor phase pads are marked A, B and C. The control side includes TX, S and G markings; verify the corresponding signal and harness connections before installation.
Can UltroNiu support OEM supply or custom PCB/PCBA?
Yes. Share order quantity, the motor and battery configuration, control interface and relevant design requirements to discuss product supply or a separate custom manufacturing project.
Request a quote for the 120A 12S Single ESC
Discuss your UAV motor-control requirements
Tell us your motor and propeller combination, battery configuration, expected current profile, control interface, target quantity and delivery schedule. For a custom PCB/PCBA program, include drawings or BOM files where available.
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