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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LDK120C12R

Name: LDK120C12R
Brand: STMicroelectronics
SKU: LDK120C12R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LDK120C12R

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 5-TSSOP, SC-70-5, SOT-353

Datasheet:: LDK120C12R.pdf

Description:: IC REG LIN 1.2V 200MA SOT323-5

Quantity:: RFQ Add To RFQ list

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Inventory:430

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Product details

Overview

LDK120C12R from STMicroelectronics is a 200 mA, 1.2 V fixed-output low-dropout (LDO) regulator in SOT323-5L package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and 100 µA max quiescent current - designed for power-sensitive battery-operated systems such as mobile phones and digital still cameras.

For engineers reviewing the LDK120C12R datasheet, LDK120C12R pinout, LDK120C12R application, or LDK120C12R equivalent, key selection criteria include its ultra-low noise (51 µVRMS with 10 nF bypass), logic-controlled shutdown (<1 µA OFF-mode current), ceramic-capacitor compatibility (1 µF COUT), and operation across –40 °C to 125 °C junction temperature.

Technical Context

The LDK120C12R implements a PMOS pass transistor architecture enabling very low dropout voltage and stable regulation down to 1.9 V input. Its internal bandgap reference and error amplifier deliver tight DC accuracy and low load/line regulation (0.006 %/mA and 0.05 %/V respectively).

Noise performance is enhanced via an optional external 10 nF bypass capacitor on the BYP pin, reducing output noise to 51 µVRMS (10 Hz–100 kHz); without it, noise rises to 148 µVRMS. The device integrates thermal shutdown (160 °C, 20 °C hysteresis) and short-circuit current limiting (~400 mA).

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 1.2 V ±2.0% at 25 °C - ensures stable core/bias rail for low-voltage logic and sensors.
Max output current	200 mA guaranteed - supports moderate-power peripherals like camera modules or RF front-ends.
Dropout voltage	100 mV typ. at 100 mA - enables operation from single-cell Li-ion (3.0 V min) or two-cell NiMH (2.4 V min) with margin.
Quiescent current	60 µA typ. (100 µA max) - extends battery life in always-on standby modes.
Output noise	51 µVRMS (10 Hz–100 kHz, with 10 nF BYP cap) - meets noise-sensitive analog/RF supply requirements.
Input voltage range	1.9 V to 5.5 V - compatible with wide-input portable power rails including USB, boost converters, and multi-cell batteries.
Enable threshold	V_EN(H) = 1.2 V min, V_EN(L) = 0.4 V max - interfaces directly with 1.8 V or 3.3 V GPIO without level-shifting.
Operating temp	–40 °C to 125 °C junction - qualified for automotive infotainment and industrial handheld applications.

Pinout & Package

LDK120C12R is packaged in SOT323-5L - a 5-pin, surface-mount plastic package measuring 2.0 × 2.1 mm with 0.65 mm pitch, optimized for space-constrained portable designs.

Pin/Terminal	Circuit Role	Design Meaning
1 (IN)	Input voltage supply	Accepts 1.9–5.5 V DC; requires local 1 µF ceramic decoupling capacitor (CIN).
2 (GND)	Power ground reference	Common return path for input, output, and enable; must be low-impedance connection to PCB ground plane.
3 (EN)	Logic enable control	Active-high input: >1.2 V = ON, <0.4 V = shutdown (<1 µA I_Q); CMOS-compatible drive.
4 (BYP/NC)	Bypass capacitor terminal (fixed version)	Optional 10 nF ceramic capacitor reduces output noise to 51 µVRMS; if unused, leave floating (no PCB trace).
5 (OUT)	Regulated output	Delivers stable 1.2 V ±2% to load; requires 1 µF ceramic output capacitor (COUT) for stability.

Key Features

Feature	Design Value
Ultra-low noise with bypass	51 µVRMS (10 Hz–100 kHz) - enables clean power for ADCs, PLLs, and RF ICs without additional filtering.
Sub-µA shutdown current	<1 µA total supply current in OFF mode - critical for long-term battery storage and zero-power wake-up circuits.
Ceramic capacitor stability	Stable with 1 µF X5R/X7R MLCC on output - eliminates need for costly tantalum or electrolytic capacitors.
Integrated protection	Thermal shutdown (160 °C) + short-circuit current limit (~400 mA) - prevents damage during fault conditions without external circuitry.
Wide input range	1.9 V to 5.5 V operation - supports direct connection to Li-ion, Li-Po, USB, and regulated DC-DC outputs.

Applications

Mobile Phone Power Management

Digital Still Camera Sensor Bias

Use Scenario: Providing clean, low-noise 1.2 V bias to image sensor analog front-end and ISP core logic during capture mode.

IC Role / Device Role / Timing Role: Primary LDO for sensor analog supply rail, delivering stable voltage under dynamic load transients (1–200 mA step changes).

Use Value: 51 µVRMS noise and fast load transient response (<50 µs settling) prevent image artifacts and color distortion.

Use Scenario: Supplying regulated 1.2 V to low-power microcontroller and memory interface in compact point-and-shoot cameras.

IC Role / Device Role / Timing Role: Standby-mode LDO with EN-controlled shutdown, enabling <1 µA system sleep current.

Use Value: 100 µA max quiescent current and –40 °C to 125 °C rating ensure reliable operation across environmental extremes.

Cordless Phone Base Station MCU

PDA Application Processor Core Rail

Use Scenario: Powering 1.2 V core of Bluetooth SoC in cordless phone base station during active call and idle listening states.

IC Role / Device Role / Timing Role: Secondary LDO downstream of main DC-DC converter, rejecting switching noise via 55 dB SVR (120 Hz–10 kHz).

Use Value: 55 dB supply rejection and 100 mV dropout allow use with loosely regulated intermediate rails while maintaining core voltage integrity.

Use Scenario: Delivering precise 1.2 V to ARM-based application processor core in legacy PDA platforms with tight thermal constraints.

IC Role / Device Role / Timing Role: Low-thermal-resistance LDO (R_thJA = 246 °C/W in SOT323-5L) operating near 125 °C junction limit.

Use Value: Thermal shutdown with 20 °C hysteresis prevents latch-up during sustained 200 mA loads in sealed enclosures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B122MR-G	1.2 V fixed, 200 mA, 65 mV dropout @ 100 mA, 35 µA I_Q, SOT23-5 - lower dropout but no BYP pin or thermal shutdown.	Lacks bypass-capable noise reduction and thermal protection - unsuitable for high-reliability or noise-critical designs.	Choose only if lowest possible dropout and minimal I_Q outweigh missing protections and noise performance.
Richtek RT9013-12GB	1.2 V fixed, 300 mA, 250 mV dropout @ 150 mA, 60 µA I_Q, SOT23-5 - higher dropout, no BYP option, 150 °C thermal shutdown.	Higher dropout limits usable input range; no noise optimization path - better for cost-sensitive non-RF applications.	Select when higher output current headroom is needed and noise/thermal specs are secondary.

Compared with XC6219B122MR-G and RT9013-12GB, LDK120C12R uniquely balances ultra-low noise (with BYP), robust thermal/short-circuit protection, and sub-µA shutdown - making it optimal for premium portable devices where reliability and signal integrity are non-negotiable.

Availability

LDK120C12R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, cordless phone systems, and PDAs requiring stable component supply with full production lifecycle support through July 2026.

Supply support for LDK120C12R 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, microcontroller, power, and sensor solutions for automotive, industrial, 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 quiescent current, high PSRR, and guaranteed 200 mA output under thermally constrained conditions.

FAQ

What is the minimum input voltage required for LDK120C12R to maintain regulation at 200 mA load?

The LDK120C12R requires VIN ≥ VOUT + VDROP to sustain regulation. At 200 mA and 1.2 V output, typical dropout is 150 mV (max 300 mV per datasheet Table 4). Thus, minimum VIN is 1.35 V (typical) or 1.5 V (worst-case), though absolute minimum operating VIN is specified as 1.9 V across all conditions - ensuring margin for line/load transients and temperature drift.

Can LDK120C12R be used with a 10 µF ceramic output capacitor instead of the recommended 1 µF?

Yes - the LDK120C12R remains stable with output capacitances from 1 µF to 22 µF (per Table 4), including 10 µF X5R/X7R MLCCs. Larger values improve load transient response and reduce output ripple, but do not degrade stability. ESR must remain below 10 Ω (typical for ceramic caps), and no series resistor is needed.

Is the BYP pin mandatory for LDK120C12R operation?

No - the BYP pin is optional. When unused, it must be left floating (no PCB trace or connection). Using a 10 nF ceramic capacitor between BYP and GND reduces output noise from 148 µVRMS to 51 µVRMS (10 Hz–100 kHz), but regulation, dropout, and basic functionality are fully maintained without it.

Does LDK120C12R support reverse polarity protection on the IN pin?

No - the LDK120C12R has no built-in reverse-polarity protection. Applying negative voltage to IN (beyond –0.3 V absolute maximum rating) may cause permanent damage. External protection (e.g., series Schottky diode or ideal diode controller) is required if reverse input is possible in the system design.

LDK120C12R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 5-TSSOP, SC-70-5, SOT-353

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 1.2V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.3V @ 200mA

Current - Output:: 200mA

Current - Quiescent (Iq):: 60 µA

Current - Supply (Max):: 100 µA

PSRR:: 55dB (120Hz ~ 10kHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323-5

LDK120C12R FAQ

1.How can I place an order for LDK120C12R through Aetrix?

Please submit a Request for Quotation (RFQ) for LDK120C12R on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LDK120C12R reliable?

The price and inventory of LDK120C12R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDK120C12R is usually 5 days.

3.What payment methods are accepted for LDK120C12R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDK120C12R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LDK120C12R?

LDK120C12R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LDK120C12R order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LDK120C12R?

For technical support, including LDK120C12R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDK120C12R requirements.

6.How does Aetrix verify that LDK120C12R is sourced from the original manufacturer or authorized distributors?

All LDK120C12R products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LDK120C12R meets industry standards.

7.What is the process for return or replacement of LDK120C12R?

All LDK120C12R units undergo pre-shipment inspection (PSI). If there is an issue with LDK120C12R, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LDK120C12R part is unused and in its original packaging.

Return procedure for LDK120C12R:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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