Overview
The LDS3985M18R, produced by STMicroelectronics, is a very low drop and low noise BiCMOS 300 mA voltage regulator. This device is designed to operate with an input voltage range of 2.5 V to 6 V and is stable with low ESR ceramic capacitors and high-quality tantalum capacitors. The ultra-low dropout voltage, low quiescent current, and low noise characteristics make it highly suitable for low power applications and battery-powered systems. The regulator also features a shutdown logic control function, allowing parts of the board to be put in standby mode, thereby reducing total power consumption. Typical applications include mobile phones, battery-powered wireless systems, and portable information appliances.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Input Voltage | 2.5 V to 6 V | V |
| Output Voltage (nominal) | 1.8 V | V |
| Output Current (nominal) | 300 mA | A |
| Dropout Voltage (typical at 300 mA load) | 150 mV | mV |
| Quiescent Current (typical at no load) | 85 µA | µA |
| Quiescent Current (typical at 300 mA load) | 200 µA | µA |
| Quiescent Current (maximum in OFF mode) | 1.5 µA | µA |
| Turn-on Time (typical) | 240 µs | µs |
| Output Noise Voltage (RMS over 10 Hz to 100 kHz) | 30 µV | µV |
| Supply Voltage Rejection (SVR) at 1 kHz | 55 dB | dB |
| Supply Voltage Rejection (SVR) at 10 kHz | 50 dB | dB |
| Operating Temperature Range | -40 °C to 125 °C | °C |
| Package Type | SOT23-5L |
Key Features
- Input voltage range from 2.5 V to 6 V
- Stable with low ESR ceramic capacitors and high-quality tantalum capacitors
- Very low dropout voltage (150 mV typical at 300 mA load, 0.4 mV typical at 1 mA load)
- Very low quiescent current (85 µA typical at no load, 200 µA typical at 300 mA load; maximum 1.5 µA in OFF mode)
- Guaranteed output current up to 300 mA
- Wide range of output voltages available on request: fixed from 1.25 V to 5 V with 100 mV step
- Fast turn-on time: typical 240 µs
- Logic-controlled electronic shutdown
- Internal current and thermal limit
- Low output voltage noise: 30 µV RMS over 10 Hz to 100 kHz
- SVR of 55 dB at 1 kHz, 50 dB at 10 kHz
- Temperature range: -40 °C to 125 °C
- Automotive grade product available in DFN6 package, temperature range: -40 °C to 85 °C
Applications
The LDS3985M18R is typically used in various low power and battery-powered applications, including:
- Mobile phones and similar battery-powered wireless systems
- Portable information appliances
- Low power electronic devices requiring stable and efficient voltage regulation
- Battery-powered systems where low quiescent current and low noise are critical
Q & A
- What is the input voltage range of the LDS3985M18R?
The input voltage range of the LDS3985M18R is from 2.5 V to 6 V.
- What is the typical dropout voltage of the LDS3985M18R at 300 mA load?
The typical dropout voltage at 300 mA load is 150 mV.
- What is the quiescent current of the LDS3985M18R at no load and at 300 mA load?
The quiescent current is typically 85 µA at no load and 200 µA at 300 mA load.
- What is the maximum output current of the LDS3985M18R?
The guaranteed output current is up to 300 mA.
- Does the LDS3985M18R have a shutdown function?
Yes, the LDS3985M18R features a logic-controlled electronic shutdown function.
- What is the turn-on time of the LDS3985M18R?
The turn-on time is typically 240 µs.
- What is the output noise voltage of the LDS3985M18R?
The output noise voltage is 30 µV RMS over 10 Hz to 100 kHz.
- What is the operating temperature range of the LDS3985M18R?
The operating temperature range is from -40 °C to 125 °C.
- Is the LDS3985M18R RoHS compliant?
Yes, the LDS3985M18R is RoHS compliant.
- What package types are available for the LDS3985M18R?
The LDS3985M18R is available in SOT23-5L and DFN6 packages.
