Description

The MAX1902EAI+ is a buck-topology, step-down, switch-mode power-supply controller used to generate logic-supply voltages in battery-powered systems. This high-performance device includes 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. The efficiency of up to 97% is achieved through synchronous rectification and Maxim's proprietary Idle Mode™ control scheme. The efficiency is greater than 80% over a 1000:1 load-current range, which extends battery life in systems' suspend or standby mode, while the excellent dynamic response corrects output load transients within five clock cycles.

Specifications and features

- Efficiency: 97%
- Input Range: 4.2V to 30V
- Dual Adjustable Outputs: 2.5V to 5.5V
- Selectable 3.3V and 5V Fixed or Adjustable Outputs (Dual Mode™)
- Linear Regulator: 12V
- Adjustable Secondary Feedback (MAX1901/MAX1904)
- Linear Regulator Output: 5V/50mA
- Precision 2.5V Reference Output
- Programmable Power-Up Sequencing
- Power-Good (RESET) Output
- Output Overvoltage Protection (MAX1901/MAX1902)
- Output Undervoltage Shutdown (MAX1901/MAX1902)
- Low-Noise: 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 MAX1902EAI+ can be used in various electronic devices such as:

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

Comparison

• High efficiency
• On-board power-up sequencing
• Low dropout circuitry
• Precision 2.5V Reference Output
• Programmable power-up sequencing
• Output overvoltage protection
• Low quiescent power
• Low dropout voltage
• Undervoltage shutdown protection

• Only used in battery-powered systems
• May not be compatible with certain devices that require a higher voltage input range