Texas Instruments LMQ664x0/LMQ664x0-Q1 Step-Down Converter

Texas Instruments LMQ664x0/LMQ664x0-Q1 Synchronous Step-Down Converter is a small 36V, 3A (available in 2A and 1A variants) synchronous step-down DC/DC converter with an integrated bypass and bootstrap capacitor. These come in an enhanced HotRod™ QFN package. This easy-to-use converter supports a wide input voltage range of 2.7V to 36V (after start-up or after operating) with transients up to 42V.

The LMQ664x0 is designed to meet low standby power requirements for always-on industrial applications. The auto mode enables frequency foldback when operating at light loads, allowing an unloaded typical current consumption of 1.5µA at 13.5VIN and high light load efficiency. A seamless transition between PWM and PFM modes and very low MOSFET ON resistances ensures exceptional efficiency across the entire load range. The control architecture (peak current mode) and feature set are optimized for an ultra-small solution size with minimal output capacitance. The device minimizes input filter size using a dual-random spread spectrum (DRSS), a low-EMI enhanced HotRod™ QFN package, and an optimized pin-out. The MODE/SYNC and RT pin variants can be used to set or synchronize the frequency to avoid noise-sensitive frequency bands. There are NC pins between critical high voltage pins, reducing potential failures (optimal pin FMEA). The rich feature set of the Texas Instruments LMQ664x0 is designed to simplify implementation for a wide range of industrial end equipment.


  • Designed for industrial applications
    • Junction temperature range –40°C to +150°C
    • NC pin between critical pins for better reliability
    • Excellent in-class pin FMEA
    • Input transient protection up to 42V
    • 2.7V (falling threshold) to 36V wide input voltage range after start-up
    • Adjustable output up to 95% of VIN, 3.3V, and 5V fixed VOUT options available
  • Functional Safety-Capable
    • Documentation available to aid functional safety system design
  • Greater than 85% efficiency at 1mA
  • Optimized for low EMI requirements
    • Integrated bypass and boot capacitors reduce EMI
    • The Dual Random Spread Spectrum reduces peak emissions
    • Enhanced HotRod™ QFN package minimizes switch node ringing
    • Adjustable FSW: 200kHz–2.2MHz with RT pin
  • Miniature solution size and low component cost
    • Integrated input bypass capacitors and bootstrap capacitor reduce EMI
    • 2.6mm × 2.6mm Enhanced HotRod™QFN package with wettable flanks
    • Internal compensation


  • Factory automation: PLC, DCS, and PAC
  • Test and measurement
  • Medical
  • Aerospace and defense

Functional Block Diagram

Block Diagram - Texas Instruments LMQ664x0/LMQ664x0-Q1 Step-Down Converter
Published: 2023-02-22 | Updated: 2023-08-28