Professional IC Distribution & Technical Solutions

The part L9935 is manufactured by STMicroelectronics. Below are the specifications, descriptions, and features based on the available knowledge:

Specifications:

• Manufacturer: STMicroelectronics
• Type: Dual Full-Bridge Driver
• Operating Voltage: 5.5V to 36V
• Output Current: Up to 1.5A per channel (peak)
• Operating Temperature Range: -40°C to +150°C
• Package: PowerSO-20

Description:

The L9935 is a dual full-bridge driver designed for DC motor and inductive load control applications. It integrates two independent H-bridges, allowing bidirectional control of two motors or a single stepper motor.

Features:

• Dual H-Bridge Configuration
• Low Saturation Voltage
• Built-in Protection Features (Overcurrent, Overtemperature, Undervoltage Lockout)
• PWM Capability for speed control
• TTL/CMOS Compatible Inputs

This information is strictly based on the manufacturer's datasheet and technical documentation.

# L9935 Motor Driver: Application Scenarios, Design Pitfalls, and Implementation Considerations

## Practical Application Scenarios

The ST L9935 is a versatile dual H-bridge motor driver IC designed for bidirectional DC motor control in automotive and industrial applications. Its robust architecture makes it suitable for:

1. Automotive Actuators

The L9935 is widely used in throttle control, exhaust gas recirculation (EGR) valves, and turbocharger actuators. Its ability to handle high currents (up to 1.5A per channel) and operate in harsh environments (-40°C to +150°C) ensures reliable performance under extreme conditions.

2. Industrial Automation

In conveyor systems, robotic arms, and CNC machines, the L9935 provides precise PWM-based speed and direction control. Its integrated protection features (overcurrent, overtemperature, and short-circuit detection) minimize downtime in high-duty-cycle applications.

3. Consumer Electronics

The IC’s low standby current (typ. 10µA) suits battery-operated devices like smart blinds or camera gimbals, where energy efficiency is critical.

## Common Design Pitfalls and Avoidance Strategies

1. Thermal Management Issues

*Pitfall:* Inadequate heat dissipation can trigger thermal shutdown, especially in high-load applications.

*Solution:* Use a PCB with sufficient copper area for the exposed pad (PowerSSO-36 package). A 4-layer board with thermal vias is recommended for high-current designs.

2. EMI and Noise Susceptibility

*Pitfall:* Poor layout practices can lead to electromagnetic interference, affecting motor performance.

*Solution:* Place decoupling capacitors (100nF ceramic + 10µF tantalum) close to the VCC pins. Route motor traces away from sensitive analog signals and use twisted-pair cables for long motor leads.

3. Incorrect Bootstrap Capacitor Selection

*Pitfall:* Undersized bootstrap capacitors cause high-side gate drive voltage droop, leading to MOSFET malfunctions.

*Solution:* Select a 100nF low-ESR ceramic capacitor (X7R or better) per H-bridge, placed within 5mm of the BSx pins.

## Key Technical Considerations for Implementation

1. Supply Voltage Range

The L9935 operates from 5V to 28V, but derating may be necessary for sustained operation above 24V due to increased thermal stress.

2. Logic-Level Compatibility

The control inputs (IN1, IN2, EN) are 3.3V/5V compatible, but a level shifter is required if interfacing with lower-voltage microcontrollers (e.g., 1.8V).

3. Diagnostic Features

Leverage the fault output pin (ERROR) to implement real-time monitoring. A pull-up resistor (10kΩ typical) to VCC is required for proper operation.

By addressing these factors, designers can optimize the L9935’s performance while mitigating risks in demanding applications.