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STMicroelectronics LD2985BM285R
- Part No.:
- LD2985BM285R
- Manufacturer:
- STMicroelectronics
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LD2985BM285R.pdf
- Description:
- IC REG LIN 2.85V 150MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,315
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Product details
Overview
LD2985BM285R from STMicroelectronics is a 150 mA fixed-output low-dropout linear voltage regulator with 2.85 V nominal output, 280 mV dropout at 150 mA, 30 µVrms output noise, and logic-controlled inhibit function. It operates from −40 °C to 125 °C in SOT23-5L and targets battery-powered portable electronics requiring ultra-low quiescent current and clean power rails.
For engineers reviewing the LD2985BM285R datasheet, LD2985BM285R pinout, LD2985BM285R application, or LD2985BM285R equivalent, key selection criteria include dropout voltage under load, inhibit input logic thresholds (VIL = 0.15 V, VIH = 2 V), thermal resistance (RthJA = 255 °C/W), bypass capacitor dependency for noise reduction, and SOT23-5L layout constraints.
Technical Context
The LD2985BM285R integrates a PNP pass transistor with internal current and thermal limiting, enabling stable 2.85 V regulation across 1–150 mA loads while maintaining sub-1 µA shutdown current when INHIBIT is pulled low. Its architecture relies on external 10 nF bypass capacitance between Bypass and GND to achieve 30 µVrms noise performance.
It features TTL-compatible inhibit control (Pin 3), no internal pull-up, and reverse-current blocking-no body diode between IN and OUT-preventing backfeed when VOUT > VIN. Line regulation is 0.003–0.014 %/V, and supply voltage rejection reaches 45 dB at 1 kHz with specified capacitors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | 2.85 V ±2.5% over −40 °C to 125 °C; ensures stable core voltage for 2.8 V–2.9 V logic domains |
| Dropout voltage | 280 mV at 150 mA; enables regulation down to VIN = 3.13 V, critical for single-cell Li-ion or Li-poly systems |
| Quiescent current | 80 µA at no load; drops to <1 µA in inhibit mode, extending battery life in standby states |
| Output noise | 30 µVrms (300 Hz–50 kHz); requires 10 nF CBYP to ground for spec compliance-directly impacts ADC reference stability |
| Supply rejection | 45 dB at 1 kHz; mitigates ripple from upstream switching converters without additional filtering stages |
| Inhibit threshold | VIL = 0.15 V max; compatible with open-drain GPIO or low-voltage logic without level-shifting |
| Thermal resistance | RthJA = 255 °C/W; limits continuous 150 mA operation to ≤75 °C ambient without PCB copper pour |
Pinout & Package
SOT23-5L package: 5-pin surface-mount, 1.45 mm height, 2.95 mm × 1.60 mm footprint, exposed pad not electrically connected. Requires reflow profile compliant with JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input voltage supply | Accepts 2.5–16 V DC; must be decoupled with ≥1 µF ceramic capacitor within 12.7 mm of pin |
| 2 (GND) | Power ground reference | Low-impedance return path for IN, OUT, and INHIBIT; connects to analog ground plane |
| 3 (INHIBIT) | Logic enable/disable control | TTL-compatible; drives regulator OFF when ≤0.15 V; must not float-tie to VI if unused |
| 4 (BYPASS) | Noise reduction node | Connects 10 nF ceramic capacitor to GND; reduces output noise from ~100 µVrms to 30 µVrms |
| 5 (OUT) | Regulated output | Delivers 2.85 V at up to 150 mA; requires 2.2 µF ceramic capacitor (low ESR) for stability per VO range |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 7 mV at 1 mA load enables micropower sensor biasing without headroom penalty |
| Sub-1 µA shutdown | Enables true zero-power sleep modes in wearables and IoT endpoints with precise timing wake-up |
| Bypass-capacitor noise reduction | 10 nF CBYP cuts broadband noise by >50%, meeting RF-sensitive analog front-end requirements |
| Reverse-current blocking | No body diode conduction prevents backfeed during hot-swap or multi-rail sequencing failures |
| Wide temperature range | −40 °C to 125 °C junction operation supports automotive cabin and industrial motor-control environments |
Applications
| Portable Medical Sensors | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Powering low-noise analog front-ends in handheld ECG or pulse oximetry units. IC Role / Device Role / Timing Role: Local 2.85 V LDO supplying ADC reference and op-amp rails. Use Value: 30 µVrms noise and 280 mV dropout preserve signal integrity and extend single-cell battery runtime beyond 72 hours. |
Use Scenario: Providing isolated 2.85 V bias for 4–20 mA transmitter signal conditioning circuits. IC Role / Device Role / Timing Role: Precision local regulator with reverse-current blocking in loop-powered field devices. Use Value: Prevents backfeed into 24 V loop during brownout, and −40 °C to 125 °C rating ensures reliability in uncontrolled cabinets. |
| Wearable Fitness Trackers | Automotive Infotainment Subsystems |
|
Use Scenario: Supplying always-on real-time clock (RTC) and accelerometer in ultra-thin wristbands. IC Role / Device Role / Timing Role: Micropower LDO with inhibit control enabling RTC-only operation during deep sleep. Use Value: 80 µA quiescent current and <1 µA inhibit mode reduce average system current to <5 µA, enabling 6-month coin-cell life. |
Use Scenario: Regulating 2.85 V for CAN transceiver logic interface in head unit domain controllers. IC Role / Device Role / Timing Role: Secondary LDO delivering clean, sequenced power to communication ICs during ignition cycles. Use Value: 45 dB PSRR suppresses switching noise from adjacent DC-DC converters, preventing CAN bit errors at 500 kbps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise, inhibit-enabled LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6219B285MR-G | 280 mV dropout at 100 mA; 25 µVrms noise; no dedicated BYPASS pin-noise filtered via output cap only | Lacks separate bypass node; requires higher-output-capacitance solution for equivalent noise performance | Select when board space prohibits 10 nF BYPASS routing but 3.3 µF ceramic output cap is acceptable |
| Diodes Inc. AP2210K-2.85TRG1 | 350 mV dropout at 150 mA; 45 µVrms noise; 1.2 µA shutdown current (vs. <1 µA) | Higher dropout and noise limit use in high-precision analog or single-cell Li-ion systems | Prefer for cost-sensitive industrial controls where 2.85 V tolerance ±3% and 70 °C ambient suffice |
Compared with XC6219B285MR-G and AP2210K-2.85TRG1, the LD2985BM285R uniquely delivers sub-1 µA shutdown, dedicated bypass pin for guaranteed 30 µVrms, and tighter output tolerance-making it optimal for battery-constrained, noise-critical portable designs.
Availability
LD2985BM285R is available at Aetrix Electronics and suitable for portable medical sensors, wearable fitness trackers, industrial PLC I/O modules, and automotive infotainment subsystems requiring stable component supply with full production lifecycle support.
Supply support for LD2985BM285R 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 components for industrial, automotive, and consumer markets.
The LD2985 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for battery-powered portable electronics demanding ultra-low dropout, micropower shutdown, and clean power delivery in compact SOT23-5L packages.
FAQ
What is the minimum input voltage required for regulation at 150 mA load?
The LD2985BM285R requires VIN ≥ VOUT + VDROP = 2.85 V + 0.28 V = 3.13 V to maintain regulation at 150 mA. Below this, output voltage collapses linearly with input; datasheet specifies absolute minimum operating input as 2.5 V, but regulation is not guaranteed below 3.13 V under full load.
Can the INHIBIT pin be left floating?
No-the INHIBIT pin has no internal pull-up or pull-down and must never be left floating. If unused, it must be tied directly to the IN pin to ensure permanent enable. Floating INHIBIT causes undefined output state and may result in erratic shutdown or oscillation due to noise coupling.
Is an external bypass capacitor mandatory for 30 µVrms noise performance?
Yes-30 µVrms noise is only achieved with a 10 nF ceramic capacitor connected between the BYPASS pin and GND. Without it, typical output noise rises to ~100 µVrms. The capacitor must be placed within 2 mm of the BYPASS and GND pins using short, low-inductance traces.
Does the LD2985BM285R support reverse-current protection?
Yes-it contains no intrinsic body diode between IN and OUT, so no reverse current flows when VOUT > VIN. Reverse current is limited to ~160 µA through internal feedback resistors (R1/R2), making it safe for hot-swap, multi-supply, or backup-battery configurations where output voltage may exceed input.
LD2985BM285R 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):
- 2.85V
- 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
LD2985BM285R FAQ
1.How can I place an order for LD2985BM285R through Aetrix?
Please submit a Request for Quotation (RFQ) for LD2985BM285R 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 LD2985BM285R reliable?
The price and inventory of LD2985BM285R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD2985BM285R is usually 5 days.
3.What payment methods are accepted for LD2985BM285R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD2985BM285R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD2985BM285R?
LD2985BM285R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD2985BM285R 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 LD2985BM285R?
For technical support, including LD2985BM285R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD2985BM285R requirements.
6.How does Aetrix verify that LD2985BM285R is sourced from the original manufacturer or authorized distributors?
All LD2985BM285R 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 LD2985BM285R meets industry standards.
7.What is the process for return or replacement of LD2985BM285R?
All LD2985BM285R units undergo pre-shipment inspection (PSI). If there is an issue with LD2985BM285R, 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 LD2985BM285R part is unused and in its original packaging.
Return procedure for LD2985BM285R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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