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STMicroelectronics LD1585CD2M-R
- Part No.:
- LD1585CD2M-R
- Manufacturer:
- STMicroelectronics
- Package:
- TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
- Datasheet:
-
LD1585CD2M-R.pdf
- Description:
- IC REG LINEAR POS ADJ 5A D2PAK-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,090
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Product details
Overview
LD1585CD2M-R from STMicroelectronics is a 5 A adjustable low-dropout linear voltage regulator in TO-220 package, featuring 1.2 V typical dropout at full load, ±1 % output voltage tolerance at 25 °C, and fast transient response optimized for low-voltage systems such as SCSI-2 active termination and industrial power rails.
For engineers reviewing the LD1585CD2M-R datasheet, LD1585CD2M-R pinout, LD1585CD2M-R application, or LD1585CD2M-R equivalent, key selection criteria include guaranteed 5 A output current, internal thermal/power limiting, minimum 10 µF output capacitor requirement, and compatibility with standard three-terminal adjustable regulator circuits.
Technical Context
The LD1585CD2M-R uses an NPN pass transistor architecture-unlike PNP-based regulators-so quiescent current flows into the load, improving efficiency. Its reference voltage is trimmed on-chip to ±1 % accuracy at 25 °C and maintains ±2 % over 0–125 °C junction temperature range.
It delivers fast line and load transient response (e.g., <10 µs recovery under 0.1–5 A step load) due to high-gain error amplifier and optimized compensation. Dropout voltage remains ≤1.4 V at 5 A and decreases linearly with lower output current, enabling operation with minimal input–output differential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | Guaranteed 5 A continuous; supports high-current analog/digital rails without external boost. |
| Dropout voltage | 1.2 V typical / 1.4 V max at 5 A; enables 3.3 V output from 4.7 V input in compact systems. |
| Output voltage tolerance | ±1 % at 25 °C; ensures precise regulation for sensitive ADC references or FPGA core supplies. |
| Line regulation | 0.1–0.2 % over VI = 2.75–15 V; minimizes output drift during input ripple or battery sag. |
| Load regulation | 0.25–0.5 % over 0–5 A; maintains stable voltage across dynamic processor or motor loads. |
| Thermal shutdown | Internally enabled; protects against sustained overload or poor heatsinking in enclosed enclosures. |
| Operating temperature | 0 °C to +125 °C junction; suitable for industrial control cabinets and non-automotive embedded environments. |
Pinout & Package
Supplied in TO-220 package with exposed tab (pin 2) for thermal conduction and mechanical mounting. Pin 1 is Adjust, Pin 2 is Output/VS, Pin 3 is Input.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (ADJ) | Reference adjust node | Connects to resistor divider to set output voltage; draws only 50–100 µA, minimizing divider power loss. |
| Pin 2 (OUT) | Regulated output terminal | High-current output path; tab is electrically connected to OUT for direct heatsink coupling. |
| Pin 3 (IN) | Unregulated input supply | Accepts up to 30 V DC input; requires ≥10 µF input capacitor for stability under fast transients. |
Key Features
| Feature | Design Value |
|---|---|
| NPN pass transistor topology | Directs quiescent current into load instead of ground, increasing efficiency by ~1–3 % at light loads. |
| On-chip voltage reference trimming | Enables ±1 % initial output accuracy without external calibration, reducing BOM count and test time. |
| Fast transient response | Stabilizes within microseconds after 0.1–5 A load steps-critical for burst-mode digital processors. |
| Internal thermal and current limiting | Automatically reduces output current or shuts down during overtemperature or short-circuit events. |
| Low external component count | Requires only two resistors (for adjustment) and one 10 µF output capacitor-no bypass or feedforward caps needed. |
Applications
| SCSI-2 Active Termination | Industrial 3.3 V/5 V Power Rail |
|---|---|
Use Scenario: Maintaining precise 2.85 V termination voltage across SCSI bus lines under hot-plug and signal reflection conditions. IC Role / Device Role / Timing Role: Adjustable LDO providing stable, low-noise termination bias independent of host supply variations. Use Value: Ensures signal integrity and bus reliability via ±1 % output tolerance and sub-10 µs transient recovery. |
Use Scenario: Delivering clean, regulated 3.3 V or 5 V to PLC I/O modules, sensor interfaces, and isolated communication peripherals. IC Role / Device Role / Timing Role: Primary local regulator converting unregulated 12 V or 24 V industrial rail to logic-level supply. Use Value: Sustains 5 A peak current during actuator switching while maintaining <0.5 % load regulation. |
| Embedded System Core Supply | Test Equipment Power Module |
Use Scenario: Powering FPGA configuration circuitry and low-power microcontrollers where input voltage margin is constrained. IC Role / Device Role / Timing Role: Low-dropout regulator enabling operation from marginal input sources like aging batteries or shared DC-DC outputs. Use Value: 1.2 V typical dropout allows 3.3 V output from 4.5 V input-maximizing usable input range and runtime. |
Use Scenario: Providing stable, low-noise bench power for calibrating DMMs, oscilloscopes, and signal generators. IC Role / Device Role / Timing Role: Precision voltage source with tight tolerance and low RMS noise (0.003 % of VO) for metrology-grade references. Use Value: Delivers ±1 % accuracy and <0.02 %/W thermal regulation-critical for traceable calibration workflows. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM338KTP/NOPB | 3 A max output, 2 V typical dropout, ±2 % output tolerance, TO-220 package. | Limited to medium-current applications; less suitable for 5 A SCSI termination or industrial 3.3 V rails. | Select when cost sensitivity outweighs current/headroom requirements and 1.2 V dropout is not critical. |
| LT1083CP#PBF | 7.5 A max output, 1.5 V dropout at 7.5 A, ±1 % tolerance, TO-220 package. | Higher current capability but larger quiescent current (10 mA vs. LD1585's ~5 mA), slightly slower transient response. | Prefer when >5 A headroom is required and thermal design accommodates higher dissipation. |
Compared with LM338KTP/NOPB and LT1083CP#PBF, the LD1585CD2M-R offers optimal balance of 5 A capability, 1.2 V dropout, and ±1 % accuracy in TO-220-making it ideal for space-constrained, high-efficiency industrial and interface power designs where both current and precision matter.
Availability
LD1585CD2M-R is available at Aetrix Electronics and suitable for SCSI-2 termination circuits, industrial 3.3 V/5 V power rails, and embedded system core supplies requiring stable component supply and long-term manufacturability.
Supply support for LD1585CD2M-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 analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.
The LD1585C series belongs to ST's high-current linear regulator product line, engineered specifically for low-dropout, fast-response applications in industrial control, test equipment, and legacy interface standards like SCSI-2.
FAQ
What is the minimum output capacitor required for stability?
The LD1585CD2M-R requires a minimum 10 µF tantalum or aluminum electrolytic capacitor at the output for unconditional stability across all load and input conditions. Ceramic capacitors may be used if ≥22 µF and paired with a 1–2 Ω series ESR resistor to emulate tantalum behavior.
Can the LD1585CD2M-R be used in parallel for higher current?
No-parallel operation is not supported. The device lacks current-sharing features or master-slave control. Attempting parallel connection risks thermal runaway due to mismatched dropout voltages and thermal coefficients between units.
Is the TO-220 tab electrically connected to any pin?
Yes-the metal tab is internally connected to Pin 2 (Output). This provides both thermal conduction to the heatsink and electrical continuity to the regulated output rail, simplifying mechanical mounting but requiring insulating hardware if the heatsink is grounded.
What is the maximum input voltage rating?
The absolute maximum DC input voltage is 30 V. Operation above 25 V is discouraged for extended periods due to increased power dissipation and thermal stress; recommended maximum continuous input is 24 V with adequate heatsinking at full 5 A load.
LD1585CD2M-R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-263-4, D2PAK (3 Leads + Tab), TO-263AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 28.6V
- Voltage Dropout (Max):
- 1.4V @ 5A
- Current - Output:
- 5A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- -
- PSRR:
- 75dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- D2PAK-3
LD1585CD2M-R FAQ
1.How can I place an order for LD1585CD2M-R through Aetrix?
Please submit a Request for Quotation (RFQ) for LD1585CD2M-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 LD1585CD2M-R reliable?
The price and inventory of LD1585CD2M-R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1585CD2M-R is usually 5 days.
3.What payment methods are accepted for LD1585CD2M-R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1585CD2M-R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD1585CD2M-R?
LD1585CD2M-R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD1585CD2M-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 LD1585CD2M-R?
For technical support, including LD1585CD2M-R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1585CD2M-R requirements.
6.How does Aetrix verify that LD1585CD2M-R is sourced from the original manufacturer or authorized distributors?
All LD1585CD2M-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 LD1585CD2M-R meets industry standards.
7.What is the process for return or replacement of LD1585CD2M-R?
All LD1585CD2M-R units undergo pre-shipment inspection (PSI). If there is an issue with LD1585CD2M-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 LD1585CD2M-R part is unused and in its original packaging.
Return procedure for LD1585CD2M-R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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