MS3111S Overview
The RELMON MS3111S is a highly integrated low-voltage brushed DC (BDC) motor driver IC providing a complete H-bridge driving solution in a minimal SOT-23-6 footprint. Designed for supply voltages from 1.8V to 6V, the device is optimised for single-cell and dual-cell Li-ion battery-powered applications where compact PCB area and low operating voltage are primary design constraints. The MS3111S delivers a continuous output current of 800mA and handles peak currents up to 1A, making it well matched to small brushed DC motors found in handheld consumer and imaging products.
The MS3111S employs a PWM IN/IN input interface, the industry-standard two-pin control scheme in which each input pin independently controls one side of the H-bridge, enabling forward, reverse, brake, and coast operating modes directly from a microcontroller’s GPIO or PWM output with no additional logic translation required. An on-resistance of RDS(on) = 850mΩ (combined high-side and low-side) keeps conduction losses low at the device’s rated operating voltages, improving overall system efficiency in battery-powered designs. Integrated over-temperature protection shuts the device down automatically if die temperature exceeds safe limits, protecting both the IC and the motor under stall or short-circuit conditions without requiring external protection circuitry.
The compact SOT-23-6 package of the RELMON MS3111S makes it one of the smallest fully integrated brushed motor driver solutions available, ideal for space-constrained PCB designs where a discrete MOSFET H-bridge is impractical. Its combination of ultra-low supply voltage operation, PWM compatibility, and integrated protection makes it a natural fit for portable, coin-cell, or single-Li-cell motion control applications.
Key Specifications
| Parameter | Value |
|---|---|
| Part Number | MS3111S |
| Manufacturer | RELMON |
| Supply Voltage Range | 1.8V to 6V |
| Continuous Output Current (IOutput) | 800mA |
| Peak Output Current (IPeak) | 1A |
| On-Resistance (RDS(on)) | 850mΩ |
| Input Interface | PWM (IN/IN) |
| Drive Topology | H-bridge (integrated) |
| Motor Type Supported | Brushed DC (BDC) |
| Protection Features | Over-temperature protection |
| Package | SOT-23-6 |
| RoHS Compliance | Yes |
Applications
The RELMON MS3111S is well suited to any compact, battery-powered application requiring low-voltage brushed DC motor control in minimal board space. Primary application areas include digital and video cameras (lens autofocus and iris actuators), handheld toys and robotic kits, portable personal care devices, compact home appliances, and coin-operated vending mechanisms. Its 1.8V minimum supply voltage and SOT-23-6 footprint also make it a strong candidate for wearable haptic actuator drives and ultra-compact IoT devices where a single Li-ion or alkaline cell powers the entire system.
Pin-to-Pin Compatible Alternatives
Replacing an established Western brand motor driver with a pin-to-pin compatible device such as the MS3111S allows design teams to reduce unit BOM cost and improve supply chain resilience with no PCB or firmware changes required.
| Reference Part Number | Original Manufacturer | Why Choose MS3111S |
|---|---|---|
| DRV8837 | Texas Instruments | Pin-to-pin compatible replacement with equivalent PWM IN/IN interface; significant cost reduction at volume through ABL Semi’s UK supply chain |
| DRV8833 | Texas Instruments | MS3111S offers a comparable low-voltage H-bridge solution in the same compact footprint at a lower unit price for high-volume consumer production |
| TC78H621FNG | Toshiba | Direct functional replacement with identical SOT-23-6 package; MS3111S provides a cost-competitive alternative with factory-authenticated UK supply |
| BD6211F-E2 | ROHM Semiconductor | Compatible low-voltage BDC motor driver; RELMON MS3111S offers equivalent performance with flexible MOQ for both prototype and mass production sourcing |
Frequently Asked Questions
Is MS3111S RoHS compliant?
Yes. The RELMON MS3111S is manufactured in compliance with the RoHS Directive (2011/65/EU), restricting hazardous substances including lead, cadmium, and mercury. Compliance documentation is available upon request through ABL Semi.
What are the pin-to-pin replacements for MS3111S?
The MS3111S is a pin-to-pin compatible replacement for widely used low-voltage brushed DC motor drivers including the TI DRV8837, TI DRV8833, Toshiba TC78H621FNG, and ROHM BD6211F. Please refer to the compatibility table above for a specific advantage comparison for each substitution.
What is the minimum order quantity (MOQ) for MS3111S?
ABL Semi offers flexible MOQ for MS3111S, supporting both prototype quantities and mass production orders. Contact us for current stock and pricing.
What package options are available for MS3111S?
The RELMON MS3111S is available in the SOT-23-6 package, a compact 6-pin small-outline transistor format widely used in space-constrained portable PCB designs and fully compatible with standard SMT reflow assembly. Contact ABL Semi to confirm current stock availability and lead times.
Does the MS3111S support PWM speed control for brushed DC motors?
Yes. The MS3111S features a PWM IN/IN input interface, meaning motor speed is controlled by varying the duty cycle of the PWM signal applied to the input pins directly from a microcontroller. Both input pins accept PWM signals independently, allowing the host MCU to command forward, reverse, brake, and coast modes as well as proportional speed control across the full 1.8V–6V supply range — with no additional external logic or gate drive components required.
For complete product specifications, please refer to: