New Industry Products

Maxim Introduces Automotive Buck Converters with Low-IQ LDO Mode

September 21, 2006 by Jeff Shepard

Maxim Integrated Products Inc. introduced the MAX5096/MAX5097 easy-to-use, 40V input, Dual Mode™ buck converters with user-selectable low-dropout (LDO) mode. At a high-output load, the converters reduce power dissipation by operating as high-efficiency, pulse-width modulated (PWM) switch-mode buck converters. During a key-off condition, the system's microcontroller drives the LDO or /BUCK input pin on-the-fly and forces the change to LDO mode, thus reducing the quiescent current (IQ). For example, the quiescent current is only 41µA at 100µA load in LDO mode. The flexible configuration, low IQ operation, protection features, and thermal enhancement make these converters ideal for low-cost, compact, automotive dc-dc applications.

In buck mode, the MAX5096/MAX5097 operate from a 5 to 40V input-voltage range and deliver up to 600mA of load current with excellent load and line regulation. In LDO mode, these converters operate from a 4V cold crank to 40V input voltage. LDO mode operation is intended for a lower output load current (up to 100mA).

These devices operate at a fixed-switching frequency of 135kHz (MAX5096) or 330kHz (MAX5097). In addition, the converters' internal dc-dc converter clock can be synchronized to an external clock. The devices use external compensation, which allows the use of low-cost inductors and output capacitors while optimizing loop stability. Additional features include current-mode control for ease of design, power-on reset output with a capacitor-adjustable timeout period, programmable soft-start, output tracking, output overload, and short-circuit/ thermal-shutdown protections.

The MAX5096/MAX5097 operate over the -40°C to +125°C automotive temperature range, and are available in thermally enhanced 20-pin TSSOP and 16-pin TQFN packages. Prices start at $2.74 (1000-up, FOB USA).