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STMicroelectronics LD2985AM30R
- Part No.:
- LD2985AM30R
- Manufacturer:
- STMicroelectronics
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LD2985AM30R.pdf
- Description:
- IC REG LINEAR 3V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,709
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Product details
Overview
LD2985AM30R from STMicroelectronics is a 150 mA fixed-output low-dropout linear voltage regulator delivering 3.0 V with 280 mV dropout at 150 mA load, 30 µVrms output noise (with 10 nF bypass capacitor), and logic-controlled inhibit shutdown reducing quiescent current to <1 µA. It serves as a local power rail regulator in portable battery-powered systems requiring ultra-low noise and standby power optimization.
For engineers reviewing the LD2985AM30R datasheet, LD2985AM30R pinout, LD2985AM30R application, or LD2985AM30R equivalent, key selection criteria include dropout performance at light/heavy loads, inhibit input logic thresholds (VIL = 0.15 V, VIH = 2 V), thermal resistance (RthJA = 255 °C/W), and ceramic capacitor stability requirements for 3.0 V output.
Technical Context
The LD2985AM30R employs a PNP pass transistor architecture enabling ultra-low dropout-7 mV at 1 mA and 280 mV at 150 mA-while maintaining tight output regulation (±2.4% over -40 °C to 125 °C). Its inhibit function is TTL-compatible and requires external pull-up when unused; floating INHIBIT is prohibited.
Output noise is actively suppressed via dedicated Bypass (BP) pin: a 10 nF capacitor to GND reduces integrated noise to 30 µVrms (300 Hz–50 kHz). Internal current and thermal limiting protect against fault conditions without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.0 V ±2.4% over full temperature and load range (1–150 mA) |
| Dropout Voltage | 280 mV at 150 mA load; enables operation with VI ≥ 3.28 V-critical for single-cell Li-ion or 3.3 V rail derivation |
| Quiescent Current | 80 µA typical at no load; drops to <1 µA in inhibit-off state-extends battery life in sleep modes |
| Output Noise | 30 µVrms (300 Hz–50 kHz) with 10 nF BP capacitor-meets analog sensor/RF front-end noise budgets |
| Inhibit Logic Thresholds | VIL ≤ 0.15 V (disable), VIH ≥ 2 V (enable); supports direct GPIO control without level-shifting |
| Thermal Resistance | RthJA = 255 °C/W in SOT23-5L-limits max ambient to ~85 °C at 150 mA continuous without derating |
| Stability Capacitors | Requires 2.2 µF ceramic output cap (low-ESR); input cap ≥1 µF-ensures phase margin >60° across operating conditions |
Pinout & Package
SOT23-5L package: 5-pin surface-mount, 1.3 mm height, 2.95 mm × 1.60 mm footprint, ECOPACK® compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input supply connection | Accepts 2.5–16 V DC; must be decoupled within 12.7 mm of pin with ≥1 µF ceramic capacitor |
| 2 (GND) | Analog ground reference | Low-impedance return path for IN, OUT, BP, and INHIBIT; must connect to clean analog ground plane |
| 3 (INHIBIT) | Logic enable/disable control | TTL-compatible input; drives regulator into sub-1 µA shutdown when ≤0.15 V; must not float |
| 4 (Bypass) | Noise reduction node | Connects to GND via 10 nF capacitor to reduce output noise to 30 µVrms; no internal bias |
| 5 (OUT) | Regulated output terminal | Delivers 3.0 V @ up to 150 mA; requires 2.2 µF ceramic capacitor with ESR < 100 mΩ for stability |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 7 mV at 1 mA enables use in energy-harvesting or coin-cell applications where headroom is constrained |
| Sub-µA shutdown | <1 µA quiescent current in inhibit-off state meets EN 50160 standby power compliance for portable medical devices |
| Dedicated noise-reduction pin | Bypass pin allows 30 µVrms noise floor-eliminates need for post-LDO ferrite beads or second-stage filtering |
| Internal protection | Integrated current limit and thermal shutdown prevent damage during short-circuit or overload without external components |
| Wide temperature range | -40 °C to +125 °C junction operation supports under-hood automotive modules and industrial edge sensors |
Applications
| Portable Medical Sensors | Wearable Biometric Monitors |
|---|---|
Use Scenario: Powering analog front-end (AFE) of ECG/PPG sensor ICs in disposable patch monitors. IC Role / Device Role / Timing Role: Local 3.0 V LDO supplying precision ADC reference and op-amp rails. Use Value: 30 µVrms noise ensures <1 LSB error in 16-bit biomedical ADCs; 280 mV dropout extends usable battery life by 18% vs. standard LDOs. |
Use Scenario: Regulating power to optical heart-rate sensor and BLE SoC in wrist-worn fitness trackers. IC Role / Device Role / Timing Role: Dual-rail source: active mode (3.0 V @ 150 mA) and deep-sleep mode (<1 µA). Use Value: Inhibit pin synchronizes with BLE SoC's sleep signal-reducing system-wide quiescent current by 92% during idle intervals. |
| Industrial IoT Edge Nodes | Automotive Cabin Camera Modules |
Use Scenario: Providing clean 3.0 V supply to MEMS accelerometer and LoRaWAN transceiver in battery-operated condition-monitoring nodes. IC Role / Device Role / Timing Role: Primary power regulator with thermal shutdown protecting against enclosure overheating in sealed enclosures. Use Value: RthJA = 255 °C/W allows full 150 mA output at 70 °C ambient-enabling fanless deployment in dusty factory environments. |
Use Scenario: Powering image signal processor (ISP) and CMOS image sensor in AEC-Q200-compliant rear-view cameras. IC Role / Device Role / Timing Role: Secondary LDO downstream of main PMIC, delivering low-noise 3.0 V for analog pixel readout. Use Value: -40 °C to +125 °C operation satisfies automotive junction temp requirement; 2.4% output tolerance prevents ISP reset during cold cranking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6219B302MR-G | 300 mA output, 150 mV dropout at 300 mA, but higher 50 µVrms noise (no bypass pin) | Lacks dedicated noise-reduction pin-requires external RC filter to match 30 µVrms performance | Select if higher output current is required and board space permits added filtering components |
| ROHM BD3572EFJ-M | 300 mA output, 250 mV dropout at 300 mA, 45 µVrms noise, includes soft-start | Soft-start prevents inrush into large capacitive loads-but adds 2 ms startup delay unsuitable for fast wake-up systems | Select for high-capacitance loads (>10 µF) where inrush control outweighs wake-up latency |
Compared with XC6219B302MR-G and BD3572EFJ-M, the LD2985AM30R uniquely delivers 30 µVrms noise without external filtering and sub-1 µA shutdown-making it optimal for ultra-low-power, noise-sensitive portable electronics where PCB area and BOM count are constrained.
Availability
LD2985AM30R is available at Aetrix Electronics and suitable for portable medical sensors, wearable biometric monitors, industrial IoT edge nodes, and automotive cabin camera modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LD2985AM30R 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 microcontrollers, power management ICs, sensors, and analog chips for industrial, automotive, and consumer markets.
The LD2985 series belongs to ST's high-performance LDO portfolio targeting ultra-low-noise, low-quiescent-current applications in battery-powered and space-constrained electronics-emphasizing dropout minimization and EMI resilience.
FAQ
Can LD2985AM30R operate with an input voltage below 3.0 V?
No. The absolute minimum operating input voltage is 2.5 V per datasheet Table 4, but functional regulation requires VI ≥ VO + VDROP. At 150 mA load, dropout is 280 mV-so minimum viable input is 3.28 V. Below that, output collapses and regulation is lost.
What happens if the INHIBIT pin is left unconnected?
The INHIBIT pin has no internal pull-up or pull-down. Leaving it floating violates the "cannot be left floating" requirement in Table 2 and may cause erratic on/off behavior or increased quiescent current. It must be tied to IN (to enable) or GND (to disable) through a direct connection or GPIO driver.
Is a bypass capacitor mandatory for LD2985AM30R?
Yes-the 10 nF capacitor between Bypass (pin 4) and GND is required to achieve the specified 30 µVrms output noise. Without it, noise rises to 120 µVrms (per Figure 11 application note). The capacitor must be placed within 2 mm of the BP pin with low-inductance layout.
Does LD2985AM30R support reverse current protection?
Yes-its PNP pass transistor lacks an intrinsic body diode, preventing reverse current flow from OUT to IN when output voltage exceeds input. Reverse current flows only through feedback resistors (typ. 160 µA), eliminating need for external blocking diodes in back-powered systems.
LD2985AM30R 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):
- 3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.575V @ 150mA
- Current - Output:
- 150mA
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- 4 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
LD2985AM30R FAQ
1.How can I place an order for LD2985AM30R through Aetrix?
Please submit a Request for Quotation (RFQ) for LD2985AM30R 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 LD2985AM30R reliable?
The price and inventory of LD2985AM30R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD2985AM30R is usually 5 days.
3.What payment methods are accepted for LD2985AM30R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD2985AM30R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD2985AM30R?
LD2985AM30R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD2985AM30R 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 LD2985AM30R?
For technical support, including LD2985AM30R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD2985AM30R requirements.
6.How does Aetrix verify that LD2985AM30R is sourced from the original manufacturer or authorized distributors?
All LD2985AM30R 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 LD2985AM30R meets industry standards.
7.What is the process for return or replacement of LD2985AM30R?
All LD2985AM30R units undergo pre-shipment inspection (PSI). If there is an issue with LD2985AM30R, 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 LD2985AM30R part is unused and in its original packaging.
Return procedure for LD2985AM30R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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