BESCHREIBUNG

The LT3023 is a dual, micropower, low noise, low dropout regulator. With an external 0.01μF bypass capacitor, output noise drops to 20μVRMS over a 10Hz to 100kHz bandwidth. Designed for use in battery-powered systems, the low 20μA quiescent current per channel makes it an ideal choice. In shutdown, quiescent current drops to less than 0.1μA. Shutdown control is independent for each channel, allowing for fl exibility in power management. The device is capable of operating over  an input voltage from 1.8V to 20V, and can supply 100mA of output current from each channel with a dropout voltage of 300mV. Quiescent current is well controlled in dropout.

The LT3023 regulator is stable with output capacitors as low as 1μF. Small ceramic capacitors can be used without the series resistance required by other regulators.

Internal protection circuitry includes reverse battery protection, current limiting, thermal limiting and reverse current protection. The device is available as an adjustable device  with a 1.22V reference voltage. The LT3023 regulator is available in the thermally enhanced 10-lead MSOP and DFN packages.

 

FEATURES

Low Noise: 20μVRMS (10Hz to 100kHz)

Low Quiescent Current: 20μA/Channel

Breiter Eingangsspannungsbereich: 1,8V bis 20V

Output Current: 100mA/Channel

Very Low Shutdown Current: <0.1μA

Low Dropout Voltage: 300mV at 100mA

Adjustable Output from 1.22V to 20V

Stable with 1μF Output Capacitor

Stabil mit Aluminium-, Tantal- oder Keramikkondensatoren

Reverse Battery Protected

Kein Rückwärtsstrom

Keine Schutzdioden erforderlich

Overcurrent and Overtemperature Protected

Thermally Enhanced 10-Lead MSOP and DFN Packages

 

ANWENDUNGEN

Cellular Phones

Pagers

Batteriebetriebene Systeme

Frequency Synthesizers

Wireless Modems

 

ANWENDUNGSINFORMATIONEN

The LT3023 is a dual 100mA low dropout regulator with micropower quiescent current and shutdown. The device is capable of supplying 100mA per channel at a dropout voltage of 300mV. Output voltage noise can be lowered to 20μVRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.01μF reference bypass capacitor. Additionally, the reference bypass capacitor will improve transient response of the regulator, lowering the settling time for transient load conditions. The low operating quiescent current (20μA per channel) drops to less than 1μA in shutdown. In addition to the low quiescent current, the LT3023 regulator incorporates several protection features which make it ideal for use in battery-powered systems. The device is protected against both reverse input and reverse output voltages. In battery backup applications where the output can be held up by a backup battery when the input is pulled to ground, the LT3023 acts like it has a diode in series with its output and prevents reverse current flow.Additionally, in dual supply applications where the regulator load isreturned to a negative supply, the output can be pulled below ground by as much as 20V and still allow the device to start and operate.

Adjustable Operation

The LT3023 has an output voltage range of 1.22V to 20V. The output voltage is set by the ratio of two external resistors as shown in Figure 1. The device servos the output to maintain the corresponding ADJ1/ADJ2 pin voltage  at 1.22V referenced to ground. The current in R1 is then equal to 1.22V/R1 and the current in R2 is the current in R1 plus the ADJ1/ADJ2 pin bias current. The ADJ1/ADJ2 pin bias current, 30nA at 25°C, fl ows through R2 into the ADJ1/ADJ2 pin. The output voltage can be calculated using the formula in Figure 1. The value of R1 should be no greater than 250k to minimize errors in the output voltage caused by the ADJ1/ADJ2 pin bias current. Note that in shutdown the output is turned off and the divider current will be zero. Curves of ADJ1/ADJ2 Pin Voltage vs Temperature and ADJ1/ADJ2 Pin Bias Current vs Temperature appear in the Typical Performance Characteristics.