ADP2139

Data Sheet Compact, 800 mA, 3 MHz, Step-Down DC-to-DC Converter ADP2138/ADP2139 FEATURES GENERAL DESCRIPTION Input voltage: 2.3 V to 5.5 V Peak efficiency: 95% 3 MHz fixed frequency operation Typical quiescent current: 24 μA Very small solution size 6-lead, 1 mm × 1.5 mm WLCSP package Fast load and line transient response 100% duty cycle low dropout mode Internal synchronous rectifier, compensation, and soft start Current overload and thermal shutdown protections Ultralow shutdown current: 0.2 μA (typical) Forced PWM and automatic PWM/PSM modes Supported by ADIsimPower™ design tool The ADP2138 and ADP2139 are high efficiency, low quiescent current, synchronous step-down dc-to-dc converters. The ADP2139 has the additional feature of an internal discharge switch. The total solution requires only three tiny external components. When the MODE pin is set high, the buck regulator operates in forced PWM mode, which provides low peak-to-peak ripple for power supply noise sensitive loads at the expense of light load efficiency. When the MODE pin is set low, the buck regulator automatically switches operating modes, depending on the load current level. At higher output loads, the buck regulator operates in PWM mode. When the load current falls below a predefined threshold, the regulator operates in power save mode (PSM), improving light load efficiency. APPLICATIONS PDAs and palmtop computers Wireless handsets Digital audio, portable media players Digital cameras, GPS navigation ...