MAX1816

19-2569; Rev 0; 10/02 Dual Step-Down Controllers Plus LinearRegulator Controller for Notebook Computers General Description The MAX1816/MAX1994 are dual step-down controllers for notebook computer applications. BUCK1 is a CPU core regulator with dynamically adjustable output, ultrafast transient response, high DC accuracy, and high efficiency. BUCK2 is an adjustable step-down regulator for I/O and memory supplies. Both regulators employ Maxim’s proprietary Quick-PWM™ control architecture. This fastresponse, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant” on-response to load transients, while maintaining a relatively constant switching frequency. The MAX1816/MAX1994 also have a linear-regulator controller for low-voltage auxiliary power supplies. The CPU regulator supports “active voltage positioning” to reduce output bulk capacitance and lower power dissipation. A programmable gain amplifier allows the use of lower value sense resistors. Four fixed-gain settings are available (0, 1.5, 2, and 4). A differential remotesense amplifier is also included to more accurately control the voltage at the load. Accuracy is further enhanced with an internal integrator. The MAX1816/MAX1994 include a specialized digital interface that makes them suitable for mobile CPU and video processor applications. The power-good (PGOOD) output for the core regulator is forced high during VID transitions, and the LINGOOD output for the...