The MAX8732A/MAX8733A/MAX8734A dual step-down, switch-mode power-supply (SMPS) controllers generate logic-supply voltages in battery-powered systems. The MAX8732A/MAX8733A/MAX8734A include two pulse-width modulation (PWM) controllers, adjustable from 2V to 5.5V or fixed at 5V and 3.3V. These devices 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 MAX8732A/MAX8733A/MAX8734A 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. Additionally, the outputs are high impedance when VCC falls below its UVLO set point while the outputs are enabled.
Maxim's proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme operates without sense resistors and provides 100ns response to load transients while maintaining a relatively constant switching frequency.
The unique ultrasonic pulse-skipping mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications. Other features include pulse skipping, which maximizes efficiency in light-load applications, and fixed-frequency PWM mode, which reduces RF interference in sensitive applications.
The MAX8732A features a 200kHz/5V and 300kHz/3.3V SMPS for highest efficiency, while the MAX8733A features a 400kHz/5V and 500kHz/3.3V SMPS for "thin and light" applications. The MAX8734A provides a pin-selectable switching frequency, allowing either 200kHz/300kHz or 400kHz/500kHz operation of the 5V/3.3V SMPSs, respectively. The MAX8732A/MAX8733A/MAX8734A are available in 28-pin QSOP packages and operate over the extended temperature range (-40°C to +85°C).
The MAX8732A/MAX8733A/MAX8734A are pin-for-pin upgrades to the MAX1777/MAX1977/MAX1999. The MAX1999 evaluation kit (EV kit) can be used to evaluate the MAX8732A/MAX8733A/MAX8734A.
Applications
- 3- and 4-Cell Li+ Battery-Powered Devices
- Notebook and Subnotebook Computers
- PDAs and Mobile Communication Devices
