The first of a new family of low-voltage, high current low-dropout regulators (LDOs), manufactured in a small, thin, and light power package, is now available from Micrel Semiconductor, a provider of power management and high-speed communication ICs. Available in the new S-Pak package, the MIC37150/1/2 is a 1.5A LDO designed specifically for powering 1.5V, 1.8V, or 2.5V from a minimum supply of 2.25V or 3.0V. The MIC37150/1/2 features a dropout of 500mV over all conditions. The MIC37150 is a three terminal device, offering simplicity and performance. The MIC37151 includes an error flag to warn of a fault condition and an enable pin for on/off control. The MIC37152 offers the added benefit of an adjustable output voltage as well as on/off control of the output voltage. The MIC37150/1/2 is a uCap design, offering stability when driving high capacitance loads. The uCap capability permits the MIC37150/1/2 to use either tantalum capacitors or smaller, less expensive ceramic capacitors. "The device is an ideal solution for powering low-voltage ICs where real-estate is limited but performance requirements are high," said John McGinty, LDO Applications Engineer.

Features of the MIC37150/1/2 LDO include:

• 1.5A Output Capability
• Ultra-Low Dropout: 500mV @ 1.5A (over temperature)
• Fixed 1.5V, 1.65V, 1.8V, 2.5V, 3.0V, and Adjustable Outputs
• Stable with Ceramic or Tantalum Output Capacitor
• Logic Enable Input
• Fully Protected: Reverse Battery Reverse Current, Current Limit and Thermal Shutdown
• Junction Temperature Range: -40degC to +125degC
• Low Profile S-Pak

Applications include low voltage microcontrollers, multimedia and PC processor supplies, high-efficiency linear power supplies

Micrel Semiconductor, Inc., 1849 Fortune Drive, San Jose, CA 95131. Tel: 408-944-0800. www.micrel.com

This series of low dropout regulators has an impressive 500 mV dropout for powering 1.5V, 1.8V, or 2.5V from a minimum supply of 2.25V or 3.0V - over a wide temperature range. These PNP output design devices have a dropout performance that is limited only by the low V_CE saturation voltage. This is superior to the older NPN-pass transistor designs that have a minimum dropout voltage limited by the base-to-emitter voltage drop and collector-to-emitter saturation voltage. I would like to have seen some noise figure information because it would help determine how much filtering was needed.

The S-Pak is a new packaging design for Micrel. It is two-thirds the area of the traditional TO-263 package and almost half the thickness, while providing the same power handling capability. The MIC37150/1/2 is a 1.5A LDO operating from an input of 2.25V to 6.0V. It is designed to drive digital circuits requiring low voltage at high currents such as PLDs, DSPs, and microcontrollers.

The MIC37151 features an error flag circuit that monitors the output voltage and signals an error condition when the voltage is 5% below the nominal output voltage. The error flag is an open-collector output that can sink 10 mA during a fault condition. The MIC37151and 37152 also feature an enable input for on/off control of the device. The enable input is TTL/CMOS compatible for simple logic interface. When enabled, it draws approximately 15 microamps.

The MIC37150/51/52 are available in fixed and adjustable output voltages. The adjustable version is capable of 1.24V to 5.5V. The LDOs include thermal and current limit protection, as well as reverse current and reverse battery protection.

When purchased in a quantity of 1,000, price for the MIC37150/1/2 starts at $1.98. Samples are available, and production quantities are stocked to 8 weeks ARO.

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