Key Specs

SpecValueConditionSource
Control FeaturesEnableDigi-Key
Grade-Digi-Key
Input Voltage (Max)5.5VDigi-Key
Mounting Type-Digi-Key
Operating Temperature Range-40°C ~ 85°C (TA)Digi-Key
Output ConfigurationPositiveDigi-Key
Output Current (Max)300mADigi-Key
Output TypeFixedDigi-Key
Output Voltage (Max)-Digi-Key
Output Voltage (Min)3.3VDigi-Key
Package Case-Digi-Key
Protection FeaturesOver Current, Over TemperatureDigi-Key
Psrr75dB (1kHz)Digi-Key
Qualification-Digi-Key
Supplier Device PackageSOT-23-5Digi-Key
Voltage Dropout (Max)0.24V @ 300mADigi-Key

When To Use

  1. 3.3V rail @ 300mA from 5.5V supply: The ET52333’s 5.5V max input rating and 300mA typical output current align perfectly here, allowing efficient regulation with low dropout around 265mV at full load. Using a generic LDO with higher dropout or current rating mismatch risks thermal shutdown or excessive voltage drop under load.

  2. Battery-powered sensor node with enable control: The ultra-low active supply current (90 µA typical) combined with an enable pin input current near zero (0.1 µA typical) suits battery-operated designs requiring tight power gating. A synchronous buck controller would add complexity and quiescent current, risking premature battery drain.

  3. Compact industrial control board with limited PCB area: Die size under 1 mm² and small SOT-23-5 package fit tight layouts without thermal issues up to 85°C ambient. A multi-phase buck solution would occupy more board space and require complex routing, risking noise coupling and layout errors in constrained environments.

When Not To Use

  1. Output current demand > 300mA: The ET52333’s maximum output current is 300mA typical, insufficient for higher loads. Use a high-current synchronous buck with external FETs to safely handle elevated current without thermal or current-limit failures.

  2. Input voltage below 1.7V or above 5.5V: The ET52333’s input voltage range is limited to 1.7–5.5V, so it cannot operate reliably outside this window. For sub-1.7V supplies or higher-voltage rails, a synchronous buck controller or multi-phase buck controller is required.

  3. Applications demanding very low quiescent current in sleep mode: The quiescent current of 1 µA typical is too high for ultra-low power designs like coin cells or μA sleep-mode sensors. Use a low-IQ PFM buck instead to avoid battery drain during standby.

Application Notes

Gotchas

  1. [EN pin floating or noisy]: Assuming the enable pin can be left unconnected or driven by a high-impedance noisy source. This causes erratic enable/disable cycling and output voltage glitches because the weak internal pull-down (typical 1 MΩ) is insufficient to hold a stable logic state. Fix by explicitly driving EN with a clean logic signal or adding a dedicated external pull-down resistor (<1 MΩ).

  2. [Output capacitance ESR too high]: Expecting ceramic capacitors with high ESR or tantalum caps without verifying stability. Elevated ESR can cause output voltage oscillations or increased output noise beyond the 70 µVRMS typ spec. Fix by using low-ESR X7R or better ceramics within the 0.47–4.7 µF range.

  3. [Input voltage near lower limit during startup]: Designing with input voltage just above 1.7V minimum but ignoring start-up transient dips. This leads to brownout-like behavior where the device fails to regulate or exhibits extended start-up times (60 µs typical soft-start). Fix by ensuring input voltage remains above the minimum under all conditions, including transient drops.

  4. [Thermal derating invisible in main specs]: Relying solely on max 300mA output current without accounting for the 250 °C/W junction-to-ambient thermal resistance in constrained PCB layouts. This causes junction overheating and premature shutdown despite electrical load compliance. Fix by implementing thermal relief in PCB design or derating load current per thermal analysis.