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STMicroelectronics STLQ50C-R
- Part No.:
- STLQ50C-R
- Manufacturer:
- STMicroelectronics
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
STLQ50C-R.pdf
- Description:
- IC REG LIN POS ADJ 50MA SOT323-5
- Quantity:
- Payment:
- Shipping:
Inventory:23,384
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Product details
Overview
STLQ50C-R from STMicroelectronics is an adjustable-output, BiCMOS low-dropout linear regulator delivering up to 50 mA output current with only 3 µA quiescent current, 200 mV dropout at 25 mA, and operation across 2.3 V–12 V input range - designed for microcontroller power, RTC backup, and battery-powered sensor nodes requiring ultra-low standby consumption.
For engineers reviewing the STLQ50C-R datasheet, STLQ50C-R pinout, STLQ50C-R application, or STLQ50C-R equivalent, this page provides verified technical context, validated pin functions, real-world application constraints, and confirmed alternative options for low-power LDO selection in space-constrained embedded systems.
Technical Context
The STLQ50C-R uses a PMOS pass element enabling low dropout (200 mV @ 25 mA) without degrading quiescent current - maintaining 3 µA IQ across input voltages from 2.3 V to 12 V and junction temperatures from –40 °C to 125 °C. Its internal 1.222 V bandgap reference feeds an adjustable feedback loop via the ADJ pin.
Thermal protection activates linearly starting at ~125 °C and fully disables output near 163 °C; short-circuit current is voltage-dependent due to inherent PMOS characteristics, not fixed-current limiting. The device requires ≥1 µF ceramic or electrolytic output capacitance for stability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | Adjustable 1.222 V to 11 V - set by external resistor divider; enables single BOM for multiple rail requirements. |
| Quiescent Current | 3.5–6.0 µA (typ. 3 µA) - enables >10-year battery life in 10 µA-system standby applications. |
| Dropout Voltage | 200 mV @ 25 mA, 400–700 mV @ 50 mA - supports regulation down to VIN = VOUT + 0.2 V under light load. |
| Input Voltage Range | 2.3 V to 12 V - accommodates single-cell Li-ion (3.0–4.2 V), two-cell alkaline (2.4–3.2 V), and 5/9/12 V rails. |
| Load Regulation | 0.15 %/mA - ensures ≤7.5 mV output shift over full 1–50 mA load range at nominal VOUT. |
| Supply Rejection | 30 dB @ 120 Hz - suppresses ripple from noisy DC-DC pre-regulators feeding the LDO input. |
| Thermal Shutdown | Activates linearly from 125 °C, forces VO → 0 V near 163 °C - prevents permanent junction damage during sustained overload. |
Pinout & Package
Supplied in compact SOT323-5L package (2.0 × 2.1 mm footprint, 0.36 mm height), optimized for PCB area-constrained portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - ADJ | Feedback reference node | Connects to resistor divider midpoint; sets output voltage via VO = 1.222 V × (1 + R1/R2); N/C on fixed-voltage variants. |
| 2 - GND | Ground reference | Primary return path for load current and bias circuitry; must be low-impedance connection to minimize noise coupling. |
| 3 - N/C | No-connect terminal | Internally unconnected; left floating per design - no routing or soldering required. |
| 4 - IN | Input supply | Accepts 2.3–12 V DC; internal PMOS source connects here; reverse-voltage blocking diode anode tied to OUT. |
| 5 - OUT | Regulated output | Delivers stable voltage to load; requires ≥1 µF capacitor placed adjacent to pin for stability and transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 3 µA typical - extends coin-cell or primary battery life beyond 10 years in always-on sensor nodes. |
| PMOS pass transistor | Enables 200 mV dropout at 25 mA while preserving IQ - eliminates need for complex bias networks or external transistors. |
| Integrated thermal protection | Linear foldback from 125 °C to 0 V output at ~163 °C - avoids catastrophic failure during board-level thermal stress. |
| Adjustable output architecture | 1.222 V internal reference with ADJ pin - supports custom rail generation without redesigning PCB or sourcing new fixed-LDO SKUs. |
| SOT323-5L packaging | 2.0 × 2.1 mm footprint - fits within 3×3 mm area, enabling placement directly beside MCU or RTC ICs on dense wearable PCBs. |
Applications
| Portable Medical Sensors | Industrial Wireless Node Power |
|---|---|
|
Use Scenario: Continuous glucose monitor using CR2032 coin cell with 10-year shelf life requirement and 1-second wake-up interval. IC Role / Device Role / Timing Role: Primary LDO supplying 1.8 V to ultra-low-power MCU and analog front-end during active measurement bursts. Use Value: 3 µA IQ minimizes standby drain; 200 mV dropout allows usable runtime down to 2.0 V battery voltage. |
Use Scenario: Battery-powered LoRaWAN temperature/humidity node deployed in remote field locations with 5-year maintenance cycle. IC Role / Device Role / Timing Role: Regulator for 3.3 V RF transceiver and 1.8 V sensor interface, activated only during scheduled transmission windows. Use Value: Adjustable output supports dual-rail needs; SOT323-5L footprint reduces total BOM count versus discrete fixed-LDO solutions. |
| Real-Time Clock Backup | Low-Power Microcontroller Core Supply |
|
Use Scenario: Industrial PLC mainboard retaining time/date during AC power loss using supercapacitor-backed RTC circuit. IC Role / Device Role / Timing Role: Standby LDO delivering 3.3 V to RTC IC when main 5 V rail is absent; powered from 3.6 V supercap. Use Value: 3 µA IQ preserves supercap charge for >30 days; 2.3 V min input supports full discharge range of backup source. |
Use Scenario: Wearable fitness tracker with ARM Cortex-M0+ MCU operating in deep-sleep mode >99.9% of time. IC Role / Device Role / Timing Role: Core voltage regulator providing 1.2 V to MCU core domain, dynamically scaled with clock frequency. Use Value: Adjustable output enables precise core voltage tuning; low dropout maintains regulation during brief battery sag during BLE transmit bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1703T-ADJ/TO | Higher IQ (2.5 µA typ.) but wider dropout (600 mV @ 250 mA); SOT23-5 package (larger footprint). | Rated for 250 mA output - over-specified for 50 mA use case; less optimal for ultra-small PCBs. | Select if higher output current headroom or legacy SOT23-5 layout compatibility is required. |
| TCS2117-ADJ | Lower IQ (1.8 µA typ.), but narrower input range (2.2–6.5 V); no thermal foldback - only shutdown at 150 °C. | Limited to single-cell Li-ion or 3.3/5 V systems; lacks linear thermal response for gradual overload mitigation. | Select only for sub-6.5 V input systems where absolute minimum IQ outweighs thermal safety margin. |
Compared with MCP1703T-ADJ/TO and TCS2117-ADJ, the STLQ50C-R uniquely balances ultra-low IQ (3 µA), compact SOT323-5L size, linear thermal foldback, and 12 V input capability - making it optimal for long-life, space-constrained, wide-input industrial and medical sensors.
Availability
STLQ50C-R is available at Aetrix Electronics and suitable for portable medical sensors, industrial wireless nodes, RTC backup circuits, and low-power microcontroller core supplies requiring stable component supply across multi-year production cycles.
Supply support for STLQ50C-R 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 products for automotive, industrial, power management, and microcontroller markets.
The STLQ50 series belongs to ST's ultra-low-power linear regulator product line, engineered specifically for battery-operated equipment demanding multi-year operational life and minimal PCB footprint.
FAQ
What is the minimum input voltage required for regulation at 1.8 V output?
The STLQ50C-R maintains regulation down to VIN = VOUT + VDROP. At 1.8 V output and 25 mA load, dropout is 200 mV, so minimum functional input is 2.0 V. With 50 mA load, dropout rises to ~400 mV, requiring ≥2.2 V input. Below these thresholds, output collapses linearly with input.
Can the STLQ50C-R be used with ceramic output capacitors smaller than 1 µF?
No - the datasheet specifies ≥1 µF output capacitance for stability across all operating conditions. Using <1 µF ceramics risks oscillation, especially under light loads or high ESR conditions. Figure 11 confirms stable operation only with CO ≥1 µF and ESR ≤5 Ω.
How does the ADJ pin leakage affect accuracy at high-resistor-divider values?
ADJ pin leakage (~10 nA max) introduces error when R1 + R2 exceeds ~10 MΩ. For example, with R2 = 1 MΩ and R1 = 9 MΩ (VO ≈ 11 V), 10 nA through R2 creates ~10 mV offset. ST recommends R2 = 1 MΩ and limits R1 to ≤10 MΩ to keep error <0.5%.
Is reverse-voltage protection provided between IN and OUT pins?
No - the internal PMOS body diode conducts from OUT to IN when VO > VI. If reverse bias is possible (e.g., hot-swap or backup-source scenarios), an external Schottky diode in series with IN or OUT is mandatory to prevent backfeed and potential damage.
STLQ50C-R 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:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 12V
- Voltage - Output (Min/Fixed):
- 1.22V
- Voltage - Output (Max):
- 11V
- Voltage Dropout (Max):
- 0.7V @ 50mA
- Current - Output:
- 50mA
- Current - Quiescent (Iq):
- 5 µA
- Current - Supply (Max):
- 6 µA
- PSRR:
- 30dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323-5
STLQ50C-R FAQ
1.How can I place an order for STLQ50C-R through Aetrix?
Please submit a Request for Quotation (RFQ) for STLQ50C-R 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 STLQ50C-R reliable?
The price and inventory of STLQ50C-R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STLQ50C-R is usually 5 days.
3.What payment methods are accepted for STLQ50C-R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STLQ50C-R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STLQ50C-R?
STLQ50C-R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STLQ50C-R 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 STLQ50C-R?
For technical support, including STLQ50C-R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STLQ50C-R requirements.
6.How does Aetrix verify that STLQ50C-R is sourced from the original manufacturer or authorized distributors?
All STLQ50C-R 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 STLQ50C-R meets industry standards.
7.What is the process for return or replacement of STLQ50C-R?
All STLQ50C-R units undergo pre-shipment inspection (PSI). If there is an issue with STLQ50C-R, 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 STLQ50C-R part is unused and in its original packaging.
Return procedure for STLQ50C-R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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