Dual Synchronous Step-Down DC/DC Converter Delivers 95% Efficiency

Linear Technology recently announced the LT8616, a 42-V input capable, high-efficiency dual synchronous monolithic step-down switching regulator. Its dual channel design delivers independent 2.5- and 1.5-A continuous current to outputs as low as 0.8 V. A dual channel synchronous rectification topology delivers up to 95% efficiency while Burst Mode operation keeps quiescent current under 6.5 µA (both channels enabled) in no-load standby conditions, making it ideal for always-on systems. Switching frequency can be programmed from 200 kHz to 3 MHz and is synchronizable throughout this range.LT8616 Linear

The LT8616’s 35-ns minimum on-time enables 16 VIN to 1.8 VOUT step-down conversions, while switching at 2 MHz helps you avoid critical noise-sensitive frequency bands, such as AM radio while having a very compact solution footprint. Its 3.4- to 42-V input voltage range makes it ideal for automotive applications which must regulate through cold-crank and stop-start scenarios with minimum input voltages as low as 3.4 V and load dump transients in excess of 40 V. Each channel of the LT8616 maintains a minimum dropout voltage of only 400 mV (at 1 A) under all conditions, enabling it to excel in scenarios such as automotive cold-crank. The LT8616’s 28-lead thermally enhanced TSSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.

The LT8616 utilizes dual internal top and bottom high efficiency power switches with the necessary boost diodes, oscillator, control and logic circuitry integrated into a single die. Each channel switches 180° out-of-phase to reduce output ripple. Each channel has a separate input for added design flexibility. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15 mVPP. Unique design techniques and a new high speed process enable high efficiency over a wide input voltage range, and the LT8616’s current-mode topology provides fast transient response and excellent loop stability. Other features include internal compensation, power good flags, output soft-start/tracking and thermal protection.

The LT8616 is available in a thermally enhanced 28-lead TSSOP package. Three temperature grades are available, with operation from –40°C to 125°C (junction) for the extended (E) and industrial (I) grades and a high temperature (H) grade of –40°C to 150°C. The 1,000-piece price starts at $4.15.

Features

  • 3.4 to 42 V Input voltage range
  • 5- and 1.5-A Buck regulators with separate inputs
  • Fast minimum switch on-time: 35 ns
  • Ultralow quiescent current burst mode operation
  • 180° Out-of-phase switching
  • Adjustable and synchronizable: 200 kHz to 3 MHz
  • Accurate 1-V Enable pin thresholds
  • Internal compensation
  • Output soft-start and tracking
  • TSSOP Package:
  • Thermally enhanced 28-lead TSSOP package

 

Synchronous Buck Regulator with Output Tracking and Sequencing for FPGAs and Microprocessors

Intersil Corp. recently announced the availability of the ISL8002B synchronous buck (step-down) switching regulator, which delivers up to 2 A of continuous output current from a 2.7- to 5.5-V input supply. Its 2-MHz switching frequency provides superior transient response, and its key features—including programmable soft-start and output tracking and sequencing of FPGAs and microprocessors—increase system reliability for point-of load conversions in networking, factory automation, instrumentation, and medical equipment.Intersil ISL8002B

The ISL8002B enables greater system reliability through several innovative features. For example, the regulator’s output tracking and sequencing of FPGAs and MPUs ensures sensitive multi-rails properly start up and shutdown. In addition, its output rails are configurable for coincidental, ratio metric, or sequential settings, ensuring the FPGA or MPU’s internal ESD diodes are not biased or overstressed during rising or falling outputs. The ISL8002B’s undervoltage lockout and several other protection/stability features protect the system from damage from unwanted electrical fault events. And its unique negative current protection prevents switch failure.

The ISL8002B’s superior transient response and high level of integration enable a complete synchronous step-down DC/DC converter solution in less than a 0.10 in2 footprint. By integrating low RDS(ON) high-side PMOS and low-side NMOS MOSFETs, the buck regulator eliminates the need for a bootstrap capacitor and diode. Its high efficiency enables the use of small inductors to further reduce board space.

Features and specifications:

  • Dimensions: 2 mm × 2 mm
  • Output tracking and sequencing
  • Switching at high frequency, 2 MHz
  • High peak efficiency: up to 95%
  • Wide input voltage range: 2.7 to 5.5 V
  • Maximum output current: 2A
  • Under voltage lockout, overvoltage protection
  • Selectable PFM or PWM operation
  • Over current, short-circuit protection
  • Over temperature/thermal protection

The ISL8002B synchronous buck regulator is available in a 2 mm  × 2 mm, eight-pin TDFN package. It costs $1 in 1,000-piece quantities. The ISL8002B DEMO1Z demonstration board is available for $23.

Source: Intersil Corp.