General Description

The MAX1887/MAX1897 step-down slave controllers are intended for low-voltage, high-current, multiphase DC-to-DC applications. The MAX1887/MAX1897 slave controllers can be combined with any of Maxim’s Quick-PWM™ step-down controllers to form a multiphase DC-to-DC converter. Existing Quick-PWM controllers, such as the MAX1718, function as the master controller, providing accurate output voltage regulation, fast transient response, and fault protection features. Synchronized to the master’s low-side gate driver, the MAX1887/MAX1897 include the Quick-PWM constant on-time controller, gate drivers for a synchronous rectifier, active current balancing, and precision current-limit circuitry.

Features

♦ Quick-PWM Slave Controller

♦ Precise, Active Current Balance (±1.25mV )

♦ Accurate, Adjustable Current-Limit Threshold

♦ Optimized for Low-Output Voltages (≤2V)

♦ 4V to 28V Battery Input Range

♦ Fixed 300kHz (MAX1887) or Selectable 200kHz/300kHz/550kHz (MAX1897) Switching Frequency

♦ Drive Large Synchronous-Rectifier MOSFETs

♦ 525µA (typ) ICC Supply Current

♦ 20µA Standby Supply Current

♦ <1µA Shutdown (MAX1897) Supply Current

♦ Small 16-Pin QSOP (MAX1887), Compact

20-Pin 5mm x 5mm QFN (MAX1897), or

20-Pin 5mm x 5mm Thin QFN (MAX1897)

Applications

Notebook Computers

CPU Core Supply

Single-Stage (BATT to VCORE) Converters

Two-Stage (5V to VCORE) Converters

Servers/Desktop Computers

Telecom