The MAX796/MAX797/MAX799 high-performance, step-down DC-DC converters with single or dual outputs provide main CPU power in battery-powered systems. These buck controllers achieve 96% efficiency by using synchronous rectification and Maxim's proprietary Idle Mode control scheme to extend battery life at full-load (up to 10A) and no-load outputs. Excellent dynamic response corrects output transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Unique bootstrap circuitry drives inexpensive N-channel MOSFETs, reducing system cost and eliminating the crowbar switching currents found in some PMOS/NMOS switch designs. The MAX796/MAX799 are specially equipped with a secondary feedback input (SECFB) for transformer-based dual-output applications. This secondary feedback path improves cross-regulation of positive (MAX796) or negative (MAX799) auxiliary outputs. The MAX797MJE has a logic-controlled and synchronizable fixed-frequency pulse-width-modulating (PWM) operating mode, which reduces noise and RF interference in sensitive mobile-communications and pen-entry applications. The SKIP-bar override input allows automatic switchover to idle-mode operation (for high-efficiency pulse skipping) at light loads, or forces fixed-frequency mode for lowest noise at all loads. The MAX796/MAX797/MAX799 are all available in 16-pin DIP and narrow SO packages. See the table below to compare these three converters. 
Feature
 
 
  
  - 96% Efficiency 
 
  - 4.5V to 30V Input Range 
 
  - 2.5V to 6V Adjustable Output 
 
  - Preset 3.3V and 5V Outputs (at up to 10A) 
 
  - Multiple Regulated Outputs 
 
  - +5V Linear-Regulator Output 
 
  - Precision 2.505V Reference Output 
 
  - Automatic Bootstrap Circuit 
 
  - 150kHz/300kHz Fixed-Frequency PWM Operation 
 
  - Programmable Soft-Start 
 
  - 375μA Typ Quiescent Current (VIN = 12V, VOUT = 5V) 
 
  - 1μA Typ Shutdown Current 
 
 
 
  
Applications
 
 
 
  - Cell Phones
 
  - Notebook and Subnotebook Computers
 
  - PDAs and Mobile Communicators