STMicroelectronics LDK120C15R

Overview

LDK120C15R from STMicroelectronics is a 1.5 V fixed-output, 200 mA low-dropout linear regulator with 100 µA max quiescent current, 100 mV typical dropout at 100 mA, and ±2.0% output voltage tolerance at 25 °C. It features logic-controlled shutdown (EN pin), ceramic capacitor compatibility (1 µF COUT), and operates across -40 °C to 125 °C - designed for power-sensitive mobile and portable battery systems.

For engineers reviewing the LDK120C15R datasheet, LDK120C15R pinout, LDK120C15R application, or LDK120C15R equivalent, key selection criteria include ultra-low noise (51 µVRMS with bypass cap), thermal/short-circuit protection, SOT323-5L package footprint, and enable-driven power sequencing in compact handheld devices.

Technical Context

The LDK120C15R implements a PMOS pass transistor architecture enabling very low dropout voltage and stable operation with 1 µF ceramic output capacitance. Its internal bandgap reference and error amplifier deliver tight DC accuracy and low load/line regulation (0.006 %/mA and 0.05 %/V).

It integrates logic-level enable control (VIL ≤ 0.4 V, VIH ≥ 1.2 V), thermal shutdown at 160 °C with 20 °C hysteresis, and constant-current short-circuit limiting (~400 mA). The device supports both fixed-output (1.5 V) and adjustable versions via the same core topology.

Key Specifications

Pinout & Package

LDK120C15R is packaged in SOT323-5L - a 1.8 × 2.0 mm, 5-pin surface-mount package with exposed thermal pad (no internal connection), optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, low-IQ LDO applications.

Compared with XC6210B152MR-G and RT9013-15GB, LDK120C15R uniquely balances ultra-low noise (51 µVRMS), sub-100 µA IQ, 100 mV dropout, and integrated thermal hysteresis - making it optimal for noise- and efficiency-critical portable RF and imaging systems.

Availability

LDK120C15R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and cordless phone systems requiring stable component supply with full production lifecycle support through July 2026.

Supply support for LDK120C15R 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 LDK120 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for battery-powered portable electronics demanding ultra-low IQ, minimal dropout, and high PSRR in miniature packages.

FAQ

What is the minimum input voltage required for LDK120C15R to maintain regulation at full 200 mA load?

The minimum input voltage is calculated as VOUT + VDROP(max). At 200 mA and 40–125 °C, VDROP reaches 300 mV per datasheet Table 4. Thus, VIN(min) = 1.5 V + 0.3 V = 1.8 V. However, the absolute minimum specified operating VIN is 1.9 V - so 1.9 V is the guaranteed functional lower limit across temperature and process variation.

Can LDK120C15R operate with a 0.47 µF output capacitor instead of the recommended 1 µF?

No - the datasheet specifies 1 µF minimum for stability across all operating conditions. Testing shows phase margin drops below 45° with 0.47 µF, risking oscillation under load transients. Ceramic capacitors with X5R/X7R dielectric and ≤100 mΩ ESR are mandatory; smaller values violate the stability region defined in Figure 25.

Is the BYP pin required to be connected for LDK120C15R to function?

No - the BYP pin is optional. When unused, it must be left floating with no PCB routing (per Table 1 note). Connecting it to GND or VOUT will degrade noise performance and may cause instability. Only connect a 10 nF capacitor between BYP and GND if 51 µVRMS noise is required; otherwise, leave unconnected for standard operation.

Does LDK120C15R support reverse current blocking when VIN < VOUT?

No - the LDK120C15R uses a PMOS pass device without integrated reverse-current protection. If VIN falls below VOUT (e.g., during input brownout), reverse current can flow from OUT to IN unless an external Schottky diode or ideal diode controller is added. This behavior is confirmed by absence of "reverse current blocking" in features and electrical characteristics tables.