AS1358-BTTT-18

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The AS1358-BTTT-18 is a low-dropout linear regulator from the AS1358/AS1359 series, manufactured by ams-OSRAM USA INC. It provides a fixed 1.8V output with a maximum continuous load current of 150mA. The device operates within an input voltage range of 2V to 5.5V and achieves a dropout voltage as low as 70mV at 150mA. Key electrical characteristics include an ultra-low output noise of 9µVRMS (100Hz to 100kHz) and a power-supply rejection ratio exceeding 80dB up to 10kHz. Quiescent current is maintained at 40µA, dropping below 500nA in shutdown mode. It features integrated overcurrent and thermal protection and is housed in a TSOT23 5-pin package.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Ultra-low noise architecture delivering 9µVRMS output noise for sensitive analog circuits
• High power-supply rejection ratio exceeding 80dB across critical frequency ranges
• Integrated P-channel MOSFET pass transistor enabling extremely low quiescent current consumption
• Operational stability guaranteed with small-value 1µF ceramic capacitors

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Mobile phones and wireless communication devices
• Bluetooth portable radios and accessories
• Digital cameras and personal audio devices
• Battery-powered handheld computers and PDAs

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific ordering code AS1358-BTTT-18 against official manufacturer documentation to confirm the 1.8V preset output and 150mA load rating. Ensure compatibility with the required TSOT23 5-pin surface-mount package. Confirm RoHS compliance status and check for any recent product change notices regarding lead frame or assembly modifications before finalizing procurement plans.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component when designing space-constrained portable electronics requiring precise 1.8V regulation. It is suitable for applications demanding minimal power consumption during standby via its shutdown pin. Consider the 150mA current limit and thermal dissipation capabilities relative to the PCB copper area. Verify that the input voltage remains above the minimum dropout threshold under all operating conditions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

This part belongs to the AS1358/AS1359 family of ultra-low-noise LDOs designed for battery-powered systems. While the AS1359 variant supports higher currents up to 300mA, the AS1358 is optimized for 150mA loads. Both share identical architectural features, including the noise bypass circuitry and P-channel pass transistor, ensuring consistent performance profiles across the series for mobile and wireless applications.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

Direct substitutes within the same family include other AS1358 variants with different fixed output voltages, such as AS1358-BTTT-25 or AS1358-BTTT-33. Cross-family replacements require matching the 150mA current rating, 1.8V output, TSOT23-5 package, and low-noise specifications. Verify pinout compatibility and thermal resistance values before integrating alternative regulators.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

How does the BYPASS pin function?

The BYPASS pin connects to an internal noise reduction circuit. Connecting a 10nF capacitor between this pin and the OUT pin significantly reduces output voltage noise.

What is the purpose of the SHDNN pin?

The SHDNN pin controls the shutdown mode. Pulling this pin low disables the internal reference and pass transistor, reducing supply current to less than 500nA.

Is the device stable with ceramic capacitors?

Yes, the AS1358/AS1359 are specifically designed to remain stable with low-cost, small-capacitance ceramic capacitors, requiring only 1µF on both input and output pins.