Description

The MAX1901E is a buck-topology, step-down, switch-mode, power-supply controller designed for generating logic-supply voltages in battery-powered systems. This high-performance device includes various features such as on-board power-up sequencing, power-good signaling with delay, digital soft-start, secondary winding control, low dropout circuitry, internal frequency-compensation networks, and automatic bootstrapping. With up to 97% efficiency achieved through synchronous rectification and Maxim's proprietary Idle Mode™ control scheme, it extends battery life in system suspend or standby mode. The MAX1901E also offers excellent dynamic response to correct output load transients quickly. It is equipped with 1A on-board gate drivers to ensure fast external N channel MOSFET switching.

Specifications and features

• 97% Efficiency
• Input Range: 4.2V to 30V
• Dual Adjustable Outputs: 2.5V to 5.5V
• Selectable Dual Mode™: 3.3V and 5V Fixed or Adjustable Outputs
• 12V Linear Regulator
• Adjustable Secondary Feedback (MAX1901E)
• Linear Regulator Output: 5V/50mA
• Precision 2.5V Reference Output
• Programmable Power-Up Sequencing
• Power-Good (RESET) Output
• Output Overvoltage Protection (MAX1901E)
• Output Undervoltage Shutdown (MAX1901E)
• Low-Noise, Fixed-Frequency Operation: 333kHz/500kHz
• Low-Dropout, 98% Duty-Factor Operation
• Typical Quiescent Power: 2.5mW (12V input, both SMPSs on)
• Typical Shutdown Current: 4µA

Application Scenarios

The MAX1901E is suitable for various applications, including:

• Notebook and Subnotebook Computers
• PDAs and Mobile Communicators
• Desktop CPU Local DC-DC Converters

Comparison

- High efficiency up to 97%

- Wide input range of 4.2V to 30V

- Multiple adjustable and fixed output options

- Secondary feedback control

- Reliable power-up sequencing and power-good signaling

- On-board gate drivers for fast MOSFET switching

- Low quiescent power and shutdown current

- Some features are only available in certain models (e.g., output overvoltage protection and undervoltage shutdown are only present in MAX1901E)