MAX1999

Product Summary

The MAX1999 is a dual step-down, switch-mode power-supply (SMPS) controller.It generate logic-supply voltages in battery-powered systems. The MAX1999 include two pulse-width modulation (PWM) controller, adjustable from 2V to 5.5V or fixed at 5V and 3.3V. The MAX1999 feature two linear regulators providing 5V and 3.3V always-on outputs. Each linear regulator provides up to 100mA output current with automatic linear regulator bootstrapping to the main SMPS outputs. The MAX1999 include on-board power-up sequencing, a power-good (PGOOD) output, digital soft-start, and internal soft-stop output discharge that prevents negative voltages on shutdown. Applications are (1)Notebook and Subnotebook Computers; (2)PDAs and Mobile Communication Devices; (3)3- and 4-Cell Li+ Battery-Powered Devices.

Parametrics

MAX1999 absolute maximum ratings: (1)V+, SHDN to GND: -0.3V to +25V; (2)BST_ to GND: -0.3V to +30V; (3)LX_ to BST: -6V to +0.3V; (4)CS_ to GND: -2V to +6V; (5)VCC, LDO5, LDO3, OUT3, OUT5, ON3, ON5, REF, FB3, FB5, SKIP, PRO, PGOOD to GND: -0.3V to +6V; (6)DH3 to LX3: -0.3V to (VBST3 + 0.3V); (7)DH5 to LX5: -0.3V to (VBST5 + 0.3V); (8)ILIM3, ILIM5 to GND: -0.3V to (VCC + 0.3V); (9)DL3, DL5 to GND: -0.3V to (VLDO5 + 0.3V); (10)TON to GND: -0.3V to +6V; (11)LDO3, LDO5, REF Short Circuit to GND: Momentary; (12)LDO3 Current (Internal Regulator)Continuous: +100mA; (13)LDO3 Current (Switched Over to OUT3)Continuous: +200mA; (14)LDO5 Current (Internal Regulator)Continuous: +100mA; (15)LDO5 Current (Switched Over to OUT5)Continuous: +200mA; (16)Continuous Power Dissipation 28-Pin QSOP (derate 10.8mW/°C above +70°C): 860mW; (17)Operating Temperature Range : -40°C to +85°C; (18)Junction Temperature: +150°C; (19)Storage Temperature Range: -65°C to +150°C; (20)Lead Temperature (soldering, 10s): +300°C.

Features

MAX1999 features: (1)No Current-Sense Resistor Needed; (2)1.5% Output Voltage Accuracy; (3)3.3V and 5V 100mA Bootstrapped Linear Regulators; (4)Internal Soft-Start and Soft-Stop Output Discharge; (5)Quick-PWM with 100ns Load Step Response; (6)3.3V and 5V Fixed or Adjustable Outputs; (7)4.5V to 24V Input Voltage Range; (8)Ultrasonic Pulse-Skipping Mode (25kHz min); (9)Power-Good (PGOOD)Signal; (10)Overvoltage Protection Enable/Disable.

Diagrams