High-Power Synchronous HB LED Drivers with Rapid Current Pulsing

1.5MHz, 30A Synchronous LED Driver Ensures High Efficiency and Rapid Current Pulsing

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The MAX16821A/MAX16821B/MAX16821C pulse-width-modulation (PWM) LED driver controllers provide high output-current capability in a compact package with a minimum number of external components. The MAX16821A/MAX16821B/MAX16821C are suitable for use in synchronous and nonsynchronous step-down (buck), boost, buck-boost, SEPIC, and Cuk LED drivers. A logic input (MODE) allows the devices to switch between synchronous buck and boost modes of operation. These devices are the first high-power drivers designed specifically to accommodate common-anode HB LEDs.

The ICs offer average current-mode control that enable the use of MOSFETs with optimal charge and on-resistance figure of merit, thus minimizing the need for external heatsinking even when delivering up to 30A of LED current.

The differential sensing scheme provides accurate control of the LED current. The ICs operate from a 4.75V to 5.5V supply range with the internal regulator disabled (VCC connected to IN). These devices operate from a 7V to 28V input supply voltage with the internal regulator enabled.

The MAX16821A/MAX16821B/MAX16821C feature a clock output with 180° phase delay to control a second out-of-phase LED driver to reduce input and output filter capacitor size and to minimize ripple currents. The wide switching frequency range (125kHz to 1.5MHz) allows the use of small inductors and capacitors.

Additional features include programmable overvoltage protection and an output enable function.
MAX16821, MAX16821A, MAX16821B, MAX16821C: Simplified Diagram MAX16821, MAX16821A, MAX16821B, MAX16821C: Simplified Diagram Enlarge+

Key Features

  • Up to 30A Output Current
  • True-Differential Remote Output Sensing
  • Average Current-Mode Control
  • 4.75V to 5.5V or 7V to 28V Input-Voltage Range
  • 0.1V/0.03V LED Current-Sense Options Maximize Efficiency (MAX16821B/MAX16821C)
  • Thermal Shutdown
  • Nonlatching Output Overvoltage Protection
  • Low-Side Buck Mode with or without Synchronous Rectification
  • High-Side Buck and Low-Side Boost Mode with or without Synchronous Rectification
  • 125kHz to 1.5MHz Programmable/Synchronizable Switching Frequency
  • Integrated 4A Gate Drivers
  • Clock Output for 180° Out-of-Phase Operation for Second Driver
  • -40°C to +125°C Operating Temperature Range


  • Front Projectors/Rear Projection TVs
  • LCD TVs and Display Backlight
  • Portable and Pocket Projectors
Part NumberRegulation TopologyMax. No. of LEDsLED ChannelsLED ConfigurationILED per Channel
PWM Dimming Freq.
Dimming RatioDimming ControlVDROPOUT
LED String Volt.
Oper. Freq.
maxmaxmaxtypminmaxmaxmaxSee Notes
MAX16821 Inductor Based61Series30101000PWM300303004.75285.51001500
$3.16 @1k
See All LED Drivers (78)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX16821BEVKIT: Evaluation Kit for the MAX16821B

Quality and Environmental Data

Request Reliability Report for: MAX16821B 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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