STMicroelectronics LDK220U33R

Overview

LDK220U33R from STMicroelectronics is a fixed-output 3.3 V, 200 mA low-dropout linear regulator in SOT-89 package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and logic-controlled shutdown with <1 µA off-mode current. It operates from 2.5 V to 13.2 V input and supports ceramic output capacitors as low as 1 µF - ideal for space-constrained, battery-powered consumer electronics requiring stable low-noise rail generation.

For engineers reviewing the LDK220U33R datasheet, LDK220U33R pinout, LDK220U33R application, or LDK220U33R equivalent, key selection criteria include dropout performance at full load, thermal resistance (110 °C/W junction-to-ambient in SOT-89), enable threshold compatibility with 1.8 V/3.3 V logic, output discharge behavior, and stability with minimal 1 µF ceramic capacitance.

Technical Context

The LDK220U33R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and high PSRR (55 dB at 120 Hz–1 kHz). Its internal bias generator and thermal shutdown (160 °C) with 20 °C hysteresis ensure robust operation across -40 °C to 125 °C ambient.

Logic-controlled EN pin directly interfaces with standard CMOS levels (V_IL ≤ 0.4 V, V_IH ≥ 1.2 V); when pulled low, it activates internal 18 Ω discharge path from VOUT to GND while limiting quiescent current to ≤1 µA. The SOT-89 variant lacks ADJ and EN pins - confirming this part is fixed-output only in that package.

Key Specifications

Pinout & Package

LDK220U33R is supplied in SOT-89 package - a 3-pin, surface-mount plastic power package with exposed thermal pad (pin 2), optimized for moderate-power LDO applications requiring low thermal resistance and simple layout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with LDK220M33R, the U33R sacrifices enable control for lower thermal resistance and simpler routing; versus LDK320U33R, it trades current headroom for tighter cost and proven reliability in legacy 200 mA designs.

Availability

LDK220U33R is available at Aetrix Electronics and suitable for battery-powered equipment, set-top boxes, and industrial control systems requiring stable component supply with long-term lifecycle assurance.

Supply support for LDK220U33R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The LDK220 series targets ultra-low-quiescent, low-noise LDO applications in space- and power-constrained portable and industrial electronics - emphasizing simplicity, reliability, and wide-input-voltage flexibility.

FAQ

Is LDK220U33R compatible with 1 µF ceramic output capacitors?

Yes - the device is explicitly characterized and guaranteed stable with 1 µF ceramic capacitors (X5R/X7R) on the output, per Table 6 and Figure 22 of DS10219 Rev 7. This eliminates need for larger or more expensive tantalum types and reduces PCB area significantly.

Does LDK220U33R have an enable pin?

No - the SOT-89 package variant (U33R) does not include an enable pin or ADJ pin, as confirmed in Table 3 and Section 3 of DS10219 Rev 7. It is a permanently enabled, fixed-output device; enable functionality is only available in SOT-23-5L and DFN6 packages.

What is the maximum power dissipation for LDK220U33R in SOT-89?

Maximum power dissipation is 500 mW, derived from absolute maximum ratings (Table 4) and thermal data (Table 5): with R_thJA = 110 °C/W and T_JMAX = 125 °C, P_D = (125 − 25)/110 ≈ 0.91 W - but the datasheet specifies 500 mW as the safe operational limit to maintain reliability and avoid thermal shutdown under worst-case ambient conditions.

Can LDK220U33R be used with input voltages below 2.5 V?

No - the absolute minimum input voltage is 2.5 V, as stated in Table 6 and Section 4 of DS10219 Rev 7. Operation below this violates the operating input voltage specification and may result in unregulated output, increased dropout, or failure to maintain regulation, especially near the 3.3 V output.