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
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Battery-powered 3.3V IoT node @ 200mA: The ultra-low quiescent current of 8µA at no load maximizes battery life during sleep, while the 500mA max output current supports moderate active loads. A switching regulator might save power at higher currents but would introduce switching noise and complexity, risking analog front-end interference.
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5V automotive accessory from 12V battery @ 500mA: The 16V input max rating and reverse polarity protection cover automotive transients and miswiring. The internal current limit at 950mA prevents device damage under short circuits. Using a simple LDO without these protections risks latch-up or thermal runaway during cold-crank or fault conditions.
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Precision 1.2V rail for FPGA core power @ 400mA: The fixed output voltage with ±1% tolerance and low dropout voltage (typ 180mV) ensures stable supply close to the input voltage, minimizing power loss. Switching regulators would complicate EMI-sensitive FPGA power domains and might cause timing issues due to ripple noise.
When Not To Use
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High-current 3.3V rail @ 3A: The 500mA max output current rating is insufficient for this load. Use a high-current synchronous buck with external FETs to handle the current and maintain efficiency without overheating.
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Always-on IoT sensor powered by coin cell: Although the quiescent current is low, the typical 8µA is still too high for ultra-low power sleep modes. Use a low-IQ PFM buck regulator designed for sub-µA standby currents to maximize battery life.
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Input voltage >16V, e.g. 24V industrial rail: The absolute max input voltage of 16V is too low for this application, risking immediate device failure. Use a synchronous buck controller designed for higher input voltages to safely step down from 24V.
Application Notes
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A 10nF capacitor is recommended on the BYP pin to reduce output noise; omitting it leads to higher output ripple and slower startup time.
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Output capacitor selection impacts loop stability; a minimum of 1μF tantalum or 2.2μF aluminum electrolytic is advised, especially at higher output currents to prevent oscillations.
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The Enable pin thresholds require an input logic high >2.0V and low <0.4V; driving this pin with a voltage between these values can cause undefined regulator states or increased quiescent current.
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The device does not have a switching node (SW) since it is a linear regulator; however, keep the ground pin current return path low impedance to avoid ground bounce and erratic enable behavior.
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Layout should minimize trace length on input and output capacitors to reduce parasitic inductance and maintain transient response; place the BYP capacitor close to the IC pin.
Gotchas
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[Minimum Load Current Misassumption]: Designers often assume the device will regulate properly at very low or no load. Below about 10mA output current, the regulator’s loop gain decreases, potentially causing output voltage instability or oscillation.
Fix: Include a minimum load resistor or ensure load current exceeds 10mA during startup and light load conditions. -
[Output Capacitor ESR Overlooked]: Using low ESR ceramic capacitors exclusively can destabilize the feedback loop due to insufficient phase margin, leading to output voltage ringing or oscillations under load transient.
Fix: Use a capacitor with ESR in the datasheet-recommended range (tantalum or aluminum electrolytic) or add a small series resistance to ceramic capacitors. -
[Enable Pin Drive Level Ambiguity]: Driving the enable pin with a voltage near the threshold (around 1.5V) can cause erratic toggling or increased quiescent current, as the pin input current minimum is 3µA and thresholds are not symmetrical.
Fix: Use a dedicated logic signal rail >2.0V for enable, or add a Schmitt trigger buffer to clean the enable input. -
[Thermal Shutdown Margin Ignored]: Relying solely on the internal power dissipation limit without accounting for worst-case junction-to-ambient thermal resistance and ambient temperature can cause intermittent thermal shutdown under high ambient or low airflow.
Fix: Verify (TJ(max)-TA)/θJA thermal budget with worst-case scenarios and provide adequate PCB copper area or heatsinking.