• LM3421Q1/LM3423Q1 are Automotive Grade Products That are AEC-Q100 Grade 1 Qualified
• LM3421Q0/LM3423Q0 are Automotive Grade Products That are AEC-Q100 Grade 0 Qualified
• VIN Range From 4.5 V to 75 V
• High-Side Adjustable Current Sense
• 2-Ω, 1-A Peak MOSFET Gate Driver
• Input Undervoltage and Output Overvoltage Protection
• PWM and Analog Dimming
• Cycle-by-Cycle Current Limit
• Programmable Switching Frequency
• Zero Current Shutdown and Thermal Shutdown
• LED Output Status Flag (LM3423/23Q1/23Q0 Only)
• Fault Status Flag and Timer (LM3423/23Q1/23Q0 Only)

• LED Drivers: Buck, Boost, Buck-Boost, and SEPIC
• Indoor and Outdoor Area SSL
• Automotive
• General Illumination
• Constant-Current Regulators

The LM3421 and LM3423 family of devices are versatile high voltage N-channel MOSFET controllers for LED drivers. They can be easily configured in buck, boost, buck-boost and SEPIC topologies. This flexibility, along with an input voltage rating of 75 V, makes the LM3421 and LM3423 devices ideal for illuminating LEDs in a large family of applications.

Adjustable high-side current sense voltage allows for tight regulation of the LED current with the highest efficiency possible. The LM3421 and LM3423 devices use predictive off-time (PRO) control, which is a combination of peak current-mode control and a predictive off-timer. This method of control eases the design of loop compensation while providing inherent input voltage feed-forward compensation.

The LM3421 and LM3423 devices include a high-voltage start-up regulator that operates over a wide input range of 4.5 V to 75 V. The internal PWM controller is designed for adjustable switching frequencies of up to 2 MHz, thus enabling compact solutions.