Key Specs

SpecValueConditionSource
Output ConfigurationPositiveDigi-Key
Output TypeFixedDigi-Key
Number Of Regulators1Digi-Key
Input Voltage (Max)6VDigi-Key
Output Voltage (Min)1.5VDigi-Key
Output Voltage (Max)-Digi-Key
Voltage Dropout (Max)0.35V @ 200mADigi-Key
Output Current (Max)200mADigi-Key
Current Quiescent IQ4 µADigi-Key
Psrr44dB (100Hz)Digi-Key
Control Features-Digi-Key
Protection FeaturesOver Current, Over Temperature, Short CircuitDigi-Key
Operating Temperature Range-40°C ~ 125°CDigi-Key
Mounting TypeSurface MountDigi-Key
Package CaseTO-236-3, SC-59, SOT-23-3Digi-Key
Supplier Device PackageSOT-23-3Digi-Key

When To Use

  1. 3.3V @ 150mA from 5V USB supply: The 6V maximum input rating covers standard USB voltage with margin for transient spikes, while the 0.35V dropout at 200mA ensures stable regulation under load. Using a switching regulator here could introduce noise and complexity, and a linear regulator without sufficient dropout margin risks output collapse near dropout.

  2. Battery-powered sensor node at 1.8V @ 50mA: The ultra-low quiescent current of 4 µA minimizes battery drain in standby, and the 1.2V minimum output voltage allows regulation close to battery cutoff. Switching regulators would add complexity and EMI, while linear regulators with higher dropout voltage or quiescent current could shorten battery life or cause brownout.

  3. Powering analog circuitry at 1.5V @ 100mA from 3V rail: The fixed positive output and 44dB PSRR at 100Hz provide good noise filtering for sensitive analog loads, with reliable overcurrent and thermal protection. Switching regulators risk injecting switching noise, and linear regulators with poorer PSRR may degrade analog performance.

When Not To Use

  1. Output current > 250mA: The maximum current rating of 200–250mA is insufficient. Use a high-current synchronous buck with external FETs to handle higher load currents efficiently without thermal risk.

  2. Input voltage less than 2.3V or very low dropout needed: The minimum input voltage is 2.3V and dropout voltage can reach 0.35V at 200mA. For input voltages near or below 2.3V or dropout below 0.3V, use a low-IQ PFM buck to maintain regulation without dropout-induced voltage sag.

  3. Applications requiring galvanic isolation: This regulator lacks isolation capability and is not suitable for isolated power domains. An isolated flyback topology is required for safe and reliable isolation.

Application Notes

  1. The input and output pins require a minimum 1µF ceramic capacitor (X7R) close to the regulator terminals to maintain stability and prevent oscillations; use low ESL/ESR capacitors.

  2. The package is SOT-23-3 (TO-236-3), so thermal dissipation is limited; layout should maximize copper area on the PCB to the ground plane to reduce junction temperature rise.

  3. Noise-sensitive loads benefit from placing the output capacitor as close as possible to the regulator output pin to minimize noise coupling.

  4. The device has no switching node (SW), being a linear regulator, so no switching noise routing concerns, but guarding the input line from high-frequency noise sources improves PSRR effectiveness.

  5. Avoid routing noisy digital lines near the output pin to maintain the 44dB PSRR at 100Hz and prevent degradation of the analog output quality.

Gotchas

  1. [Low output capacitance destabilizes regulator]: Using an output capacitor below 1µF or with ESR outside 0–2Ω range can cause output voltage oscillations or instability. Symptom includes output voltage ringing or ripple observed on a scope during load transients. Fix: Use a 1µF ceramic capacitor with ESR < 2Ω placed as close as possible to the output pin.

  2. [Thermal derating above 125°C junction temperature ignored]: The device is rated only up to 125°C junction; exceeding this causes permanent damage or thermal shutdown. Designers sometimes assume the maximum storage temp (150°C) applies to operation. Symptom: regulator shuts down or output collapses under heavy load at high ambient temp. Fix: Confirm junction temperature via thermal modeling and keep TJ < 125°C under all operating conditions.

  3. [Minimum load current assumption causes undervoltage]: Operating the regulator at very low load currents (<50mA typical) without a minimum load resistor can lead to unstable regulation or output voltage drift. Symptom: output voltage rises above nominal or fluctuates during startup or no-load conditions. Fix: Add a minimum load resistor (e.g., 10kΩ) or ensure the load never falls below the stable regulation threshold.

  4. [Input voltage near dropout causes misinterpretation of regulation]: At input voltages close to 2.3V minimum, the dropout voltage can rise to 0.35V at 200mA, causing output voltage to sag below nominal without triggering fault. Symptom: output voltage slowly droops under load, causing downstream circuitry errors. Fix: Design input voltage margin > dropout voltage at maximum load or reduce load current to stay within dropout limits.