Key Specs
| Spec | Value | Condition | Source |
|---|---|---|---|
| Control Features | Enable | Digi-Key | |
| Current Quiescent IQ | 8 µA | Digi-Key | |
| Current Supply (Max) | 30 mA | Digi-Key | |
| Input Voltage (Max) | 16V | Digi-Key | |
| Mounting Type | Surface Mount | Digi-Key | |
| Number Of Regulators | 1 | Digi-Key | |
| Operating Temperature Range | -40°C ~ 125°C | Digi-Key | |
| Output Configuration | Positive | Digi-Key | |
| Output Current (Max) | 500mA | Digi-Key | |
| Output Type | Fixed | Digi-Key | |
| Output Voltage (Max) | - | Digi-Key | |
| Output Voltage (Min) | 1.2V | Digi-Key | |
| Package Case | SC-74A, SOT-753 | Digi-Key | |
| Protection Features | Over Current, Over Temperature, Reverse Polarity | Digi-Key | |
| Psrr | - | Digi-Key | |
| Supplier Device Package | SOT-23-5 | Digi-Key | |
| Voltage Dropout (Max) | - | Digi-Key |
When To Use
-
5V rail from 12V input @ 500mA: The 16V absolute maximum input voltage rating and the 450mV max dropout voltage at full load make this regulator suitable for stepping down a 12V supply to 5V with moderate current. Using a switching regulator here could reduce power dissipation but risks complexity and switching noise, while a linear regulator with insufficient dropout voltage would enter dropout and supply unstable voltage.
-
Battery-powered system needing low quiescent current @ 100mA load: The typical quiescent current of 8µA enables efficient operation in systems with long standby times and intermittent loads. A synchronous buck controller might deliver better efficiency but usually has higher quiescent current, leading to faster battery drain in low-load conditions.
-
Noise-sensitive analog supply @ 1.2V output: The fixed output voltage option with a 10nF bypass capacitor pin allows low output noise (~40µVRMS minimum), making it a good choice for sensitive analog blocks. Switching regulators or synchronous buck controllers generally produce higher output ripple and switching noise that can corrupt sensitive analog circuits.
When Not To Use
-
Load current > 500mA (e.g., 1A motor driver): The maximum output current of 500mA is insufficient for high-current loads. Use a high-current synchronous buck with external FETs to handle higher current with better thermal management and efficiency.
-
Input-output voltage differential < 0.5V with low noise requirement: The dropout voltage minimum of 2mV is low, but the max dropout voltage can be 450mV, which may cause excessive voltage drop and heat in low-dropout scenarios. Use an LDO regulator designed specifically for ultra-low dropout and low noise at small differentials.
-
Battery-powered IoT sensor with µA-level sleep current: The typical quiescent current of 8µA is relatively high for ultra-low power applications where battery life is critical. Use a low-IQ PFM buck regulator optimized for sub-µA sleep currents in intermittent load scenarios.
Application Notes
-
The BYP pin requires a 10nF capacitor to reduce output noise. Omitting this capacitor may increase output ripple and degrade regulator stability in noise-sensitive applications.
-
The output capacitor value and type strongly affect stability; a minimum of 1µF tantalum or equivalent electrolytic capacitor is recommended. Using ceramic capacitors with low ESR can sometimes cause high-frequency oscillation if not bench-tested.
-
Enable pin logic thresholds require careful attention: the input voltage must exceed 2.0V to guarantee a logic high. Applying voltages between 0.4V and 2.0V can cause undefined behavior or partial turn-on.
-
Ground pin current varies between 1mA and 30mA depending on load. PCB layout should minimize ground impedance and avoid noise coupling through ground return paths.
-
The package is SOT-23-5 (SC-74A), so thermal dissipation is limited; keep the PCB copper area adequate to maintain junction temperature below 125°C under max load.
Gotchas
-
[Incorrect output capacitor ESR assumption]: Assuming any low-ESR ceramic capacitor will guarantee regulator stability can cause high-frequency oscillations. The datasheet implies a minimum output capacitance dependent on output voltage and load current, and some ceramic capacitors with near-zero ESR can destabilize the feedback loop.
Fix: Bench test with the recommended 1µF tantalum or equivalent electrolytic capacitor, and verify stability at maximum load. -
[Enable pin threshold misinterpretation]: Designers may assume that any voltage above 0.4V on the enable pin is sufficient to turn the device on. In reality, the enable pin requires >2.0V for guaranteed logic high. Applying an intermediate voltage (0.4–2.0V) can cause the regulator to enter a partially enabled state with erratic output voltage and increased quiescent current.
Fix: Confirm enable input voltage is >2.0V or tied directly to VIN during startup. -
[Thermal derating overlooked due to package]: Using the small SOT-23-5 package with its high thermal resistance (191°C/W) without adequate PCB copper area or heat sinking leads to junction temperature quickly exceeding +125°C at high load currents, causing thermal shutdown or accelerated device degradation.
Fix: Calculate power dissipation using (TJ(max)–TA)/θJA, design PCB layout with thermal relief, and verify junction temperature under worst-case conditions. -
[Bypass capacitor omitted or undervalued]: Skipping the 10nF BYP capacitor or using a significantly lower value reduces start-up speed and increases output noise. This can cause slow regulator response to load transients and noisy output detrimental to sensitive analog circuits.
Fix: Always include a 10nF capacitor on the BYP pin as close as possible to the device pin.