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STMicroelectronics LD2982AM31R
- Part No.:
- LD2982AM31R
- Manufacturer:
- STMicroelectronics
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LD2982AM31R.pdf
- Description:
- IC REG LINEAR 3.1V 50MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,611
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Product details
Overview
LD2982AM31R from STMicroelectronics is a 50 mA fixed-output low-dropout linear voltage regulator with 1.8 V output, TTL-compatible inhibit control (Pin 3), 120 mV dropout at 50 mA, 30 µVrms output noise (with 10 nF bypass capacitor), and SOT23-5L package. It delivers ultra-low quiescent current (75 µA at 1 mA load) and supports battery-powered portable electronics requiring stable, low-noise local regulation.
For engineers reviewing the LD2982AM31R datasheet, LD2982AM31R pinout, LD2982AM31R application, or LD2982AM31R equivalent, key selection criteria include dropout performance at light loads, shutdown current (<1 µA), bypass-capacitor–enabled noise reduction, and compatibility with low-ESR ceramic capacitors in space-constrained designs.
Technical Context
The LD2982AM31R employs a PNP pass transistor architecture enabling ultra-low dropout (7 mV at 1 mA) and minimal load-dependent quiescent current variation. Its inhibit function uses direct TTL-level logic control without internal pull-up, requiring external biasing to VI or GND for reliable ON/OFF operation.
Stability is achieved with ≥1 µF ceramic output capacitance (2.2 µF recommended for 1.8 V versions), and noise performance is enhanced via dedicated Bypass pin (Pin 4) accepting a 10 nF capacitor to ground-reducing output noise to 30 µVrms over 300 Hz–50 kHz bandwidth.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V ±1 % at 25 °C - tight tolerance enables precise core/logic rail regulation without external feedback. |
| Dropout Voltage | 120 mV at 50 mA - allows operation with input as low as 1.92 V, extending battery runtime in single-cell Li-ion or NiMH systems. |
| Quiescent Current | 75 µA at 1 mA load - minimizes standby power loss; drops to <1 µA in inhibit mode for system-level power gating. |
| Output Noise | 30 µVrms (300 Hz–50 kHz, with 10 nF CBYP) - meets stringent noise requirements for RF, audio, and precision analog subsystems. |
| Supply Rejection | 45 dB at 1 kHz - suppresses ripple from noisy DC-DC converters or shared input rails in mixed-signal PCBs. |
| Operating Temp | −40 °C to +125 °C - supports industrial and automotive under-hood applications where ambient thermal stress is critical. |
| Max Input Voltage | 16 V - accommodates wide-input industrial supplies while maintaining safe margin below absolute max rating. |
Pinout & Package
SOT23-5L: 5-pin surface-mount package (2.8 × 1.75 × 1.3 mm), thermally enhanced for high ambient operation; exposed pad not present; RoHS-compliant ECOPACK®.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN | Input supply connection | Accepts 2.5–16 V DC; requires ≤0.5″ placement of 1 µF input capacitor to analog ground for stability. |
| 2 GND | Ground reference | Common return for input, output, inhibit, and bypass paths; must connect to clean analog ground plane. |
| 3 INHIBIT | Logic-controlled enable/disable | TTL-compatible; drives regulator OFF when ≤0.15 V (IINH ≤15 µA); must not float-tie to VI if unused. |
| 4 Bypass | Noise-reduction terminal | Connects 10 nF capacitor to GND to shunt internal reference noise; reduces output noise to 30 µVrms. |
| 5 OUT | Regulated output | Delivers 1.8 V @ up to 50 mA; requires 2.2 µF low-ESR ceramic capacitor (X7R) placed ≤0.5″ from pin. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 7 mV at 1 mA load enables regulation from near-dead battery cells (e.g., 1.807 V input → 1.8 V out). |
| Sub-µA shutdown | Inhibit mode draws <1 µA total current-critical for always-on sensors or real-time clock backup domains. |
| Bypass-pin noise filter | Dedicated Pin 4 accepts 10 nF cap to cut broadband noise by >20 dB versus standard LDO configurations. |
| Low-ESR capacitor support | Stable with 1 µF ceramic output caps (2.2 µF for 1.8 V), eliminating need for costly tantalum or polymer alternatives. |
| Reverse-current blocking | No body diode between IN and OUT; prevents backfeed when output voltage exceeds input (e.g., hot-swap or backup rail scenarios). |
Applications
| Portable Audio Codec Supply | Wi-Fi/Bluetooth SoC Core Rail |
|---|---|
|
Use Scenario: Powering ADC/DAC sections in Bluetooth headphones or smart speakers where PSRR and noise directly impact THD+N. IC Role / Device Role / Timing Role: Local LDO providing clean 1.8 V reference for audio codec I/O and PLL circuits. Use Value: 30 µVrms noise and 45 dB SVR prevent switching noise from DC-DC converters from modulating audio signals. |
Use Scenario: Supplying 1.8 V I/O domain of dual-band Wi-Fi 6/Bluetooth 5.3 combo chips in wearables. IC Role / Device Role / Timing Role: Low-quiescent LDO enabling fast wake-from-sleep transitions with <1 µA shutdown current. Use Value: Inhibit pin synchronizes rail disable with host processor sleep states, cutting system idle power by >40 %. |
| Industrial Sensor Node MCU Core | Automotive Cabin Camera ISP Core |
|
Use Scenario: Regulating 1.8 V core voltage for ARM Cortex-M4 microcontrollers in battery-operated environmental monitors. IC Role / Device Role / Timing Role: Primary LDO delivering regulated power to MCU VDDCORE, with thermal shutdown protection. Use Value: −40 °C to +125 °C operation and 125 °C junction limit ensure reliability in unventilated outdoor enclosures. |
Use Scenario: Powering image signal processor (ISP) core logic in AEC-Q100–qualified cabin-facing cameras. IC Role / Device Role / Timing Role: Secondary LDO generating noise-sensitive 1.8 V rail downstream of main PMIC buck converter. Use Value: 120 mV dropout preserves headroom during cold-crank transients (battery dip to 8 V), sustaining ISP operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise, low-IQ LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6219B182MR-G | 1.8 V, 100 mA, 65 mV dropout @ 100 mA, no inhibit pin, 25 µVrms noise (no bypass pin) | Lacks logic-controlled shutdown; requires external enable circuitry for power gating | Select when higher output current is needed and system-level enable control is already implemented. |
| Analog Devices ADP160ACBZ-1.8-R7 | 1.8 V, 150 mA, 195 mV dropout @ 150 mA, 22 µVrms noise, no bypass pin, 550 nA shutdown | Lower noise but higher dropout; no dedicated bypass path-noise filtering relies on output cap ESR | Prefer when sub-µA shutdown is mandatory and board space allows larger output capacitor optimization. |
Compared with XC6219B182MR-G and ADP160ACBZ-1.8-R7, the LD2982AM31R uniquely combines TTL inhibit control, bypass-pin–enabled 30 µVrms noise, and 7 mV ultra-low dropout at microamp loads-making it optimal for compact, battery-sensitive designs requiring both precision regulation and active power-state coordination.
Availability
LD2982AM31R is available at Aetrix Electronics and suitable for portable medical monitors, industrial IoT edge nodes, and automotive cabin electronics requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for LD2982AM31R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.
The LD2982 series belongs to ST's high-performance analog LDO portfolio, engineered specifically for ultra-low-noise, ultra-low-IQ regulation in space- and power-constrained portable and embedded systems.
FAQ
What is the minimum output capacitance required for stability with LD2982AM31R at 1.8 V?
The LD2982AM31R requires a minimum 2.2 µF ceramic output capacitor (X7R dielectric) for stable operation at 1.8 V output. This value ensures sufficient phase margin across temperature and load variations; using less than 2.2 µF risks oscillation unless a series resistor is added per Section 6.3 of the datasheet.
Can the INHIBIT pin be left unconnected if shutdown functionality is not used?
No-the INHIBIT pin (Pin 3) has no internal pull-up and must never be left floating. If shutdown is unused, it must be tied directly to the input voltage (VI) to maintain continuous regulator operation and avoid erratic enable behavior due to noise coupling.
How does the Bypass pin reduce output noise, and what capacitor value is specified?
The Bypass pin (Pin 4) connects to an internal bandgap reference node; adding a 10 nF capacitor to ground filters high-frequency reference noise before it modulates the error amplifier, reducing integrated output noise to 30 µVrms. Ceramic C0G/NP0 types are recommended for stable capacitance vs. voltage and temperature.
Does LD2982AM31R support reverse current protection, and how is it implemented?
Yes-LD2982AM31R blocks reverse current flow from OUT to IN because its PNP pass transistor lacks an inherent body diode. When VOUT > VIN, only leakage current (~160 µA through internal feedback resistors) flows to GND; no significant backfeed occurs, protecting upstream sources during hot-swap or backup-power transitions.
LD2982AM31R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 3.1V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.225V @ 50mA
- Current - Output:
- 50mA
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- 1.2 mA
- PSRR:
- 45dB (1kHz)
- 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-23-5
LD2982AM31R FAQ
1.How can I place an order for LD2982AM31R through Aetrix?
Please submit a Request for Quotation (RFQ) for LD2982AM31R 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 LD2982AM31R reliable?
The price and inventory of LD2982AM31R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD2982AM31R is usually 5 days.
3.What payment methods are accepted for LD2982AM31R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD2982AM31R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD2982AM31R?
LD2982AM31R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD2982AM31R 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 LD2982AM31R?
For technical support, including LD2982AM31R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD2982AM31R requirements.
6.How does Aetrix verify that LD2982AM31R is sourced from the original manufacturer or authorized distributors?
All LD2982AM31R 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 LD2982AM31R meets industry standards.
7.What is the process for return or replacement of LD2982AM31R?
All LD2982AM31R units undergo pre-shipment inspection (PSI). If there is an issue with LD2982AM31R, 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 LD2982AM31R part is unused and in its original packaging.
Return procedure for LD2982AM31R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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