peculiarity
Micro 5 SMD and SOT-23-5 packages in micro I/O
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Stable with ceramic and high quality tantalum capacitors
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Thermal shutdown and short-circuit current limiting
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The LP3985 is designed for portable and wireless applications with demanding performance and space requirements.
The LP3985 is a small 1μF ± 30% ceramic or high quality tantalum output capacitor stable. Micro SMDs require the smallest possible printed circuit board area – the total application circuit area can be less than 2.0 mm x 2.5mm at a fraction of a 1206 size.
The LP3985 is optimized for performance, with a battery-powered system providing ultra-low noise, very low dropout voltage and low quiescent current. The regulator's ground current only slightly increases dropouts, further extending battery life.
An optional external bypass capacitor reduces output noise without slowing down load transient response. Fast start-up time is achieved by utilizing an internal power circuit that actively precharges bypass capacitors.
Power rejection is introduced at low frequencies above 50 dB and begins at 1kHz. High power supply rejection is common for battery-powered circuits to maintain a low input voltage to.
The device is ideal for mobile phones and similar battery-powered wireless applications. It provides up to 150 mA, 2.5V to 6V input. The LP3985 consumes less than 1.5μA and has a fast turn-on time of more than 200μS in disable mode.
The LP3985 is available in a micro SMD with 5 bump small bumps, a micro SMD with 5 bumps with large bumps, a thin micro SMD with 5 bumps and a 5-pin SOT-23 package. Performance over the -40°C to +125°C temperature range of 2.5V, 2.6V, 2.7V, 2.8V, 2.85V, 2.9V, 3.0V. 3.1V, 3.2V, 3.3V, 4.7V, 4.75V, 4.8V and 5.0V output voltages. For other output voltages in 2.5V to 5.0V or a dual LP3985 option, please contact the National Semiconductor Sales Office.
Main specifications
2.5 to 6.0V input range
150 mA guaranteed output
50 dB PSRR at 1kHz @V IN = V OUT + 0.2V
Fast start-up time: 200μs typical
A maximum voltage drop of 100mV with a 150mA load
30μVrms Output Noise Over 10Hz to 100kHz (Typical)
-40 to +125 °C junction operating temperature range
2.5V, 2.6V, 2.7V, 2.8V, 2.85V, 2.9V, 3.0V, 3.1V, 3.2V, 3.3V, 4.7V, 4.75V, 4.8V and 5.0V output standards
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CDMA cellular handset
Broadband CDMA cellular handsets
GSM cellular handset
Portable information appliances