Analog Devices Inc. LT8642S/LT8642-1 Step-Down Silent Switchers 2

Analog Devices Inc. LT8642S/LT8642-1 Step-Down Silent Switchers 2 feature second-generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This architecture includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by eliminating layout sensitivity.

The fast, clean, low-overshoot switching edges permit high-efficiency operation, even at high switching frequencies leading to a small, overall solution size. Peak current-mode control with a 25ns minimum on-time, allows high step down ratios even at high switching frequencies. External compensation via the VC pin allows for fast transient response at high switching frequencies. The VC pin also enables current sharing and a CLKOUT pin enables synchronizing other regulators to the LT8642S.

Other operations include Burst Mode that enables low standby current consumption, forced continuous mode that can control frequency harmonics across the entire output load range, or spread spectrum operation that can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.

The LT8642S Switcher 2 provides high performance, making it ideal for noise-sensitive applications and environments.


  • Silent Switcher® 2 Architecture
    • Ultralow EMI/EMC Emissions on any PCB
    • Eliminates PCB layout sensitivity
    • Internal bypass capacitors reduce radiated EMI
    • Optional spread spectrum modulation
  • High efficiency at high frequency
    • Up to 96% efficiency at 1MHz, 12VIN to 3.3VOUT
    • Up to 95% efficiency at 2MHz, 12VIN to 3.3VOUT
  • 2.8V to 18V Wide input voltage range
  • External Compensation: Fast transient response and current sharing
  • 10A Output current
  • Low quiescent current Burst Mode® operation
    • 240µA IQ Regulating 12VIN to 1.2VOUT
    • Output ripple <10mVP-P
  • 25ns Fast minimum switch on-time
  • 50mV at 1A Low dropout under all conditions
  • Forced continuous mode
  • 200kHz to 3MHz Adjustable and synchronizable
  • Output soft-start and power good
  • Small 24-lead 4mm × 4mm LQFN package


  • Automotive
  • Automotive always-on systems
  • Automotive cold-crank
  • Automated test equipment
  • Distributed supply regulation
  • Industrial, test, and measurements
  • Medical equipment
  • Signal processing applications
  • Imaging and RF system



Application Circuit Diagram - Analog Devices Inc. LT8642S/LT8642-1 Step-Down Silent Switchers 2
Zveřejněno: 2020-02-13 | Aktualizováno: 2022-10-26