40V, 600mA Buck Converters with Low-Quiescent-Current Linear Regulator Mode

The MAX5096/MAX5097 easy-to-use, Dual Mode™, DC-DC converters operate as LDO (low dropout) or switch-mode buck converters. At a high output load, the converters operate as high-efficiency pulse-width-modulated (PWM) switch-mode converters and reduce the power dissipation. The devices switch to a low-quiescent-current (IQ) LDO mode of operation at light load. During the key-off condition, the system's microcontroller drives the LDO/active-low BUCK input on the fly and forces the MAX5096/MAX5097 into LDO Mode, thereby reducing the quiescent current significantly.

In Buck Mode, the MAX5096/MAX5097 operate from a 5V to 40V input voltage range and deliver up to 600mA of load current with excellent load and line regulation. The fixed-switching frequency versions of 135kHz and 330kHz are available. The MAX5096/MAX5097 DC-DC internal oscillator can be synchronized to an external clock. External compensation and a current-mode control scheme make it easy to design with.

In LDO Mode, the MAX5096/MAX5097 operate from a 4V to 40V input voltage. The LDO Mode operation is intended for a lower output load current of up to 100mA. The quiescent current at 100µA load in LDO Mode is only 41µA (typ).

The MAX5096/MAX5097 feature an enable input that shuts down the device, reducing the current consumption to 6µA (typ). Additional features include a power-on reset output with a capacitor-adjustable timeout period, programmable soft-start, output tracking, output overload, short-circuit and 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 or 16-pin TQFN packages.

Applications

* Home Security/Safety

* High-Efficiency Switcher Mode (Buck Mode) or Low-Quiescent-Current Linear Regulator (LDO Mode) Operation

* Wide Operating Input Voltage Range

* +5V to +40V Buck Mode

* +4V to +40V LDO Mode

* Fixed 3.3V or 5V and Adjustable (1.24V to 11V) Output Voltage Versions

* 6µA (typ) Shutdown Current

* Fixed 135kHz or 330kHz Switching Frequency

* External Frequency Synchronization

* Programmable Soft-Start

* Integrated Microprocessor Reset (Active-Low RESET) Circuit with Programmable Timeout Period

* Thermal and Short-Circuit Protection

* -40°C to +125°C Automotive Temperature Range

* Thermally-Enhanced Package Dissipates

* 2.6W at TA = +70°C (16-Pin TQFN)

* 1.7W at TA = +70°C (20-Pin TSSOP)