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LM3401 MR16 Bulb Reference Design for Non-Dimming & Dimming LED Applications

US ECCN: EAR99 US/Local Export Classification Number

Inventory: In stock
Limit:  2

Features for the LM3401-MR16DEMO

Input Voltage, VIN12 VAC
Output Voltage, VOUT6.2V
(2 series LEDs)
Input Current, IIN650 mA
LED Output Current, ILED1.0A
Input Power, PIN~7.7W
Output Power, POUT~6.2W
Power Factor0.85
SMPS TopologyBuck
NOTE: These specifications are typical values based on the LED driver being powered directly by a 12VAC supply (i.e. no electronic or magnetic step-down transformer).
  • Tested with Electronic Transformers (12VAC output)
  • Work with off the shelf dimmers with no flicker, stable operation
  • Design features the Cree MT-G LED that is optimized for MR-16 applications
  • Flicker-free operation with common Electronic Low Voltage dimmers, and Electronic Transformers

Description for the LM3401-MR16DEMO

This reference design was based on the released LM3401 evaluation board and associated application note AN-1657. The circuit and BOM was modified to optimize performance in MR16 solutions. A PCB was created that fits into the MR16 cavity. For fast bench set-up, the LM3401 evaluation board can be modified with the LM3401 MR16 bill of materials that is listed in the design document.

This design was developed to minimize the current spikes coming out of an electronic transformer to less than 5A, which is a typical transformer rating, when driving an LED MR16 circuit. The off the shelf LED MR16 solutions exhibit spikes that significantly exceed a transformer's maximum rated output current which will degrade the reliability of the transformer and reduce its operating lifetime. This LM3401 evaluation board is designed to operate (flicker-free) with common Electronic Low Voltage dimmers, and Electronic Transformers.

This design also generates a constant LED current over most of the power cycle when an electronic transformer is on versus the short bursts of current applied to an LED stack from the off the shelf LED MR16 bulbs. This results in better power factor and more stable circuit operation.