Key Specs
| Spec | Value | Condition | Source |
|---|---|---|---|
| Control Features | Enable | Digi-Key | |
| Current Quiescent IQ | 3.5 µA | Digi-Key | |
| Current Supply (Max) | 200 µA | Digi-Key | |
| Grade | Automotive | Digi-Key | |
| Input Voltage (Max) | 40V | Digi-Key | |
| Mounting Type | Surface Mount | Digi-Key | |
| Number Of Regulators | 1 | Digi-Key | |
| Operating Temperature Range | -40°C ~ 175°C (TJ) | Digi-Key | |
| Output Configuration | Positive | Digi-Key | |
| Output Current (Max) | 300mA | Digi-Key | |
| Output Type | Fixed | Digi-Key | |
| Output Voltage (Max) | - | Digi-Key | |
| Output Voltage (Min) | 3.3V | Digi-Key | |
| Package Case | 12-PowerLSOP (0.154”, 3.90mm Width) | Digi-Key | |
| Protection Features | Over Current, Over Temperature, Short Circuit, Under Voltage Lockout (UVLO) | Digi-Key | |
| Psrr | 76dB (1kHz) | Digi-Key | |
| Qualification | AEC-Q100 | Digi-Key | |
| Supplier Device Package | PWSSO-12 | Digi-Key | |
| Voltage Dropout (Max) | 1V @ 300mA | Digi-Key |
When To Use
Use the L99VR033PTR in automotive applications requiring a robust, fixed 3.3 V positive voltage regulator with an output current up to 300 mA. Its wide operating temperature range of -40°C to 175°C (TJ) and AEC-Q100 qualification make it ideal for harsh environments. This part is suitable when a low quiescent current (3.5 µA) and a high maximum input voltage of 40 V are needed.
Avoid using this regulator in applications requiring adjustable output voltages or output currents exceeding 300 mA. For higher current or adjustable voltage needs, consider other devices specifically designed for those requirements.
When Not To Use
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Supply current > 300mA: Maximum output current of 300mA is insufficient. Use a multi-phase buck controller to handle higher current demands with better thermal distribution and scalability.
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Input-output voltage differential below 1V with tight noise requirements: Voltage dropout can reach 1V at 300mA, which is too high for low-dropout scenarios. Use an LDO regulator optimized for low dropout and low output noise instead.
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Applications requiring switching frequency above 500kHz: The device is not designed for high-frequency operation beyond typical limits. Use a high-frequency buck controller if inductor size reduction and high switching frequency are critical.
Application Notes
The input pin, which can withstand up to 40 V, is the primary switching node and should be routed with the smallest possible loop area to minimize EMI. The output pin is noise-sensitive; careful PCB layout with adequate decoupling and short traces is recommended to ensure stable operation. Given the maximum output current of 300 mA and a dropout voltage of 1 V at this load, a heatsink is generally not required under typical automotive operating conditions, but thermal considerations should be evaluated in high ambient temperature environments up to 175°C junction temperature.
Gotchas
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[Underrated thermal derating at high junction temperatures]: The device is rated to 175°C junction temperature, but power dissipation derates considerably above ambient temperatures >100°C. Ignoring this leads to thermal runaway and early failure under continuous high load.
Fix: Use thermal impedance measurements and verify junction temperature under worst-case ambient conditions with real PCB layout. -
[Incorrect startup sequence causing latch-up]: Applying input voltage before the enable pin is driven high can cause unpredictable startup behavior or internal latch-up. The regulator may fail to start or output voltage may oscillate.
Fix: Ensure the enable signal is asserted only after stable input voltage is present, with a controlled rise time if possible. -
[Output capacitor ESR outside recommended range]: Using ultra-low ESR ceramics without bulk capacitance or mixing multiple capacitor types can cause regulator instability and output voltage ringing.
Fix: Follow recommended capacitor types and minimum ESR guidelines in the datasheet; verify output ripple with oscilloscope during transient load steps. -
[Long PCB trace between VIN and device]: Excessive resistance or inductance in the input supply line causes voltage dips during load transients, triggering under-voltage lockout (UVLO) and output dropouts.
Fix: Keep VIN traces short and wide; add bulk input capacitance close to the device to maintain stable input voltage.