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STMicroelectronics LDK320ADU33R — Power Management (PMIC / Gate Driver)

STMicroelectronics LDK320ADU33R LDO Regulator, 3.3V 200mA

MPNLDK320ADU33R
End of Life

STMicroelectronics LDK320ADU33R, fixed-output positive LDO regulator, 3.3V, 200mA, 0.35V dropout max, 90µA quiescent current, PSRR 88dB ~ 48dB (120Hz ~ 10kHz), SOT-89 (TO-243AA) package, -40°C to 125°C junction temperature.

$0.89Ref. price · indicative, final on quote
STMicroelectronics LDK320ADU33R datasheet (PDF)
PackagingTO-243AA
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

LDK320ADU33R specifications
ParameterValue
Output typeFixed
MountingSurface Mount
Voltage - input18V
Voltage dropout0.35V @ 200mA
Voltage - output (Min (Fixed))3.3V
Output current200mA
Current - supply100 µA
Current - quiescent90 µA
Operating temperature-40°C ~ 125°C (TJ)
PSRR88dB ~ 48dB (120Hz ~ 10kHz)
PackageTape & Reel (TR); Cut Tape (CT)
CaseTO-243AA
Protection featuresOver Current, Over Temperature
Number of regulators1
Output configurationPositive

Product details

3.3V fixed LDO for industrial and automotive rails

Key features include a maximum dropout voltage of 0.35 V at the full 200 mA load, a quiescent current of 90 µA typical, and a supply current ceiling of 100 µA. The part integrates over-current and over-temperature protection.

The LDK320ADU33R delivers 88 dB of power-supply rejection at 120 Hz, dropping to 48 dB at 10 kHz. That 88 dB at line frequency is strong — it cleans up the 100/120 Hz ripple from a rectified mains supply down to microvolt levels. The roll-off above 1 kHz means this LDO alone won't fully suppress switching-regulator ripple in the 100 kHz to 1 MHz range; a post-filter LC stage or a separate low-noise regulator is worth budgeting if the load is an analog front-end or a PLL supply.

At 200 mA with 1 V input-to-output differential, dissipation is 200 mW.

It is ROHS3 compliant. For new designs this part is a current-production choice — no EOL risk on the near horizon.

Frequently asked questions

Does LDK320ADU33R have thermal shutdown protection?

Yes, the part includes over-temperature protection as one of its integrated protection features, alongside over-current protection.

Is LDK320ADU33R a direct replacement for LD39020DTPU33R?

Both are 3.3 V fixed-output 200 mA LDOs in SOT-89 packages with the same temperature range, but the LD39020DTPU33R has a lower maximum input voltage of 5.5 V versus the LDK320ADU33R's 18 V. They are not pin-compatible substitutes — the LDK320ADU33R handles higher input rails, while the LD39020DTPU33R adds an enable pin and soft-start. Check the input voltage and control feature requirements before substituting.

What is the PSRR of LDK320ADU33R?

The power-supply rejection ratio is 88 dB at 120 Hz, rolling off to 48 dB at 10 kHz. This makes it effective for 100/120 Hz mains ripple but less so for high-frequency switching noise above 1 MHz.