Components

1A Very-Low Dropout Fast Transient Ultra-Low Noise Linear Regulator

The LD56100 from STMicroelectronics is a high accuracy voltage regulator that provides 1A of current from an input voltage ranging from 1.8V to 5.5V, with a typical dropout voltage of 120mV. It is available in DFN8 (1.2 x 1.6 mm) package, allowing the maximum space saving.

The device is stabilized with a ceramic capacitor on the output. The ultra-low drop voltage, low quiescent current and fast transient response, together with the internal soft-start circuit, make the LD56100 suitable for low power battery-operated applications.

An enable logic control function puts the LD56100 in shutdown mode allowing a total current consumption lower than 0.1µA. Short-circuit protection with current limit foldback and thermal protection are also included.

The LD56100 has an internal soft-start circuit. By increasing the start-up time up to 100µs, without the need of any external soft-start capacitor, this feature is able to keep the regulator inrush current at start-up under control.

This device integrates a MOSFET connected between Vout and GND. This transistor is activated when the EN pin goes to low logic level and has the function to quickly discharge the output capacitor when the device is disabled by the user. The device is available with or without the auto-discharge feature.

The LD56100 is protected against short-circuit on the output. When the load current increases above 1.6 A typical the device starts limiting it to the ILIM value. If the load resistance decreases even more then the foldback, circuit starts limiting the current to 0.4 A when VOUT = 0. When pulling LCON pin to ground, the ILIM and ISC values are reduced to 0.8 A and 0.18 A respectively.

Summary of Key Features

  • Input voltage from 1.8 to 5.5 V
  • Ultra-low dropout voltage (120 mV typ. at 1 A load and VOUT = 3.3 V)
  • Very low quiescent current (100 µA typ. at no-load, 0.03 µA typ. in off mode)
  • Output voltage tolerance: ± 1% from -40 °C to +85 °C
  • Ultra-low Noise: 13 µV RMS Noise from 10 Hz to 100 kHz at VOUT = 3.0 V
  • High PSRR (70 dB@1 kHz)
  • Wide range of output voltages available on request: from 1.0 V up to 5.0 V in 50 mV step
  • Logic-controlled electronic shutdown
  • Internal soft-start
  • Optional output voltage discharge feature
  • Compatible with ceramic capacitor COUT = 1 µF
  • Internal current limit foldback and thermal protections
  • Available in DFN8 (1.2×1.6 mm)
  • Operating temperature range: -40 °C to 125 °C
STMicroelectronics NV
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