Features

• Tiny 5-Lead SOT-23 Package
• Uses Tiny Capacitors and Inductor
• High Frequency Operation: 1MHz
• High Output Current: 500mA
• Low R_DS(ON) Internal Switch: 0.28 Ohms
• High Efficiency: Up to 94%
• Current Mode Operation for Excellent Line and Load Transient Response
• Short-Circuit Protected
• Low Quiescent Current: 135µA (LTC1701)
• Low Dropout Operation: 100% Duty Cycle
• Ultralow Shutdown Current: I_Q < 1µA
• Peak Inductor Current Independent of Inductor Value
• Output Voltages from 5V Down to 1.25V

Typical Application

Description

The LTC1701/LTC1701B are the industry's first SOT-23 step-down, current mode, DC/DC converters. Intended for low to medium power applications, they operate from 2.5V to 5.5V input voltage range and switch at 1MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. The output voltage is adjustable from 1.25V to 5V. A built-in 0.28 Ohm switch allows up to 0.5A of output current at high efficiency. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of loads and output capacitors.

The LTC1701 incorporates automatic power saving BurstMode operation to reduce gate charge losses when the load current drops below the level required for continuous operation. The LTC1701B operates continuously to very low load currents to provide low ripple at the expense of light load efficiency. With no load, the LTC1701 draws only 135µA. In shutdown, both devices draw less than 1µA, making them ideal for current sensitive applications.

Their small size and switching frequency enables a complete DC/DC converter function to consume less than 0.3 square inches of PC board area.