LT1764A Series 3A, Fast Transient Response, Low Noise, LDO Regulators UFEATURESDESCRIPTIO ■ Optimized for Fast Transient Response The LT®1764A is a low dropout regulator optimized for ■ Output Current: 3A fast transient response. The device is capable of supplying ■ Dropout Voltage: 340mV at 3A 3A of output current with a dropout voltage of 340mV. ■ Low Noise: 40 µ VRMS (10Hz to 100kHz) Operating quiescent current is 1mA, dropping to < 1µA in ■ 1mA Quiescent Current shutdown. Quiescent current is well controlled; it does not ■ Wide Input Voltage Range: 2.7V to 20V rise in dropout as it does with many other regulators. In ■ No Protection Diodes Needed addition to fast transient response, the LT1764A has very ■ Controlled Quiescent Current in Dropout low output voltage noise which makes the device ideal for ■ Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3.3V sensitive RF supply applications. ■ Adjustable Output from 1.21V to 20V Output voltage range is from 1.21V to 20V. The LT1764A ■ < 1µA Quiescent Current in Shutdown regulators are stable with output capacitors as low as 10µF. ■ Stable with 10µF Output Capacitor* Internal protection circuitry includes reverse battery pro- ■ Stable with Ceramic Capacitors* tection, current limiting, thermal limiting and reverse cur- ■ Reverse Battery Protection rent protection. The device is available in fixed output ■ No Reverse Current voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an adjustable ■ Thermal Limiting device with a 1.21V reference voltage. The LT1764A regu- lators are available in 5-lead TO-220 and DD packages, and U 16-lead FE packages. APPLICATIO S , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ 3.3V to 2.5V Logic Power Supply All other trademarks are the property of their respective owners. ■ Post Regulator for Switching Supplies *See Applications Information Section. UTYPICAL APPLICATIODropout Voltage 400 3.3VIN to 2.5VOUT Regulator 350 300 2.5V IN OUT 250 3A + + V 10µF* 10 IN > 3V µF* 200 LT1764A-2.5 150 SHDN SENSE *TANTALUM, GND CERAMIC OR DROPOUT VOLTAGE (mV) 100 ALUMINUM ELECTROLYTIC 50 1764 TA01 0 0 0.5 1.0 1.5 2.0 2.5 3.0 LOAD CURRENT (A) 1764 TA02 1764afb 1