Description

The MAX1549ETL+ is a dual pulse-width modulation (PWM) step-down controller designed specifically for generating low-voltage chipset and RAM power supplies in notebook computers. It provides high efficiency, excellent transient response, and high DC-output accuracy without the need for complex compensation. The controller features a fixed-frequency, current-mode PWM architecture that allows for interleaved operation of the dual step-down regulators, reducing the input capacitor requirements.

Specifications and features

• Interleaved, fixed-frequency, current-mode control architecture
• 1% VOUT accuracy over line and load
• Main Output (OUT1):
  • 0.5V to 2.0V adjustable output
  • External reference input for dynamically selectable output voltages
  • Four digitally selectable output voltages
  • Power-Good and fault blanking during transitions
• Second Output (OUT2):
  • 2.5V/1.8V fixed or 0.5V to 2.7V adjustable output
• Accurate differential current-sense inputs
• 100kHz/200kHz/300kHz/400kHz selectable switching frequency
• Output overvoltage/undervoltage protection
• Soft-start and soft-shutdown
• Drives large synchronous-rectifier FETs
• 2V ±0.6% reference output
• Separate enable inputs with accurate threshold voltages
• Separate power-good window comparators

Application Scenarios

The MAX1549ETL+ is ideal for use in notebook computers for tasks such as:

• Dynamically adjustable chipset supplies
• Video/GPU core supplies
• DDR memory termination
• CPU core or VCC supplies
• Fixed chipset/RAM supplies
• Active termination buses

Comparison

- High efficiency

- Excellent transient response

- High DC-output accuracy

- Interleaved operation reduces input capacitor requirements

- Fixed-frequency, current-mode PWM architecture

- Not suitable for applications outside of notebook computers