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Texas Instruments LMS1587CT-ADJ/NOPB
- Part No.:
- LMS1587CT-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-3
- Datasheet:
-
LMS1587CT-ADJ/NOPB.pdf
- Description:
- IC REG LINEAR POS ADJ 3A TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:435
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Product details
Overview
LMS1587CT-ADJ/NOPB from Texas Instruments is a 3A adjustable low-dropout linear regulator in TO-220 (NDE) package, featuring 1.25V reference voltage, 1.3V typical dropout at 3A, and fast transient response optimized for microprocessor core supplies. It delivers stable output voltage set via two external resistors and includes thermal shutdown and current limiting.
For engineers reviewing the LMS1587CT-ADJ/NOPB datasheet, LMS1587CT-ADJ/NOPB pinout, LMS1587CT-ADJ/NOPB application, or LMS1587CT-ADJ/NOPB equivalent, this page provides verified specifications, package details, real-world use cases, and validated alternative options for power supply design in embedded and industrial systems.
Technical Context
The LMS1587CT-ADJ/NOPB implements a zener-trimmed bandgap reference with internal current limiting and thermal protection circuitry. Its control loop maintains regulation across input voltages from 2.75V to 13V and load currents up to 3A, with dropout voltage defined at 1% VOUT deviation.
It operates over 0°C to 125°C junction temperature range and requires only two external resistors to configure output voltage per VOUT = VREF(1 + R2/R1) + IADJR2, where IADJ ≤120 µA ensures minimal error in standard resistor selections.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A maximum continuous - supports high-current logic rails and processor core supplies without derating at TA ≤ 70°C with adequate heatsinking. |
| Dropout Voltage | 1.3V typical at 3A - enables operation with VIN as low as VOUT + 1.3V, critical for low-voltage system designs. |
| Reference Voltage | 1.250V ±1.2% - sets precision of adjustable output; determines minimum resolvable VOUT step when using standard resistor values. |
| Line Regulation | 0.005% typical - ensures <±0.17mV change in VOUT per 1V input variation, supporting stable rail generation under varying input conditions. |
| Load Regulation | 0.05% typical - guarantees <±1.65mV shift in VOUT from no-load to full 3A, essential for tight-tolerance digital supply applications. |
| Ripple Rejection | 72dB at 120Hz - suppresses input ripple effectively, reducing need for large input filtering capacitors in noisy environments. |
| Quiescent Current | 7–13mA - remains constant across load and input range, enabling predictable bias power consumption in always-on subsystems. |
Pinout & Package
Package: TO-220 (NDE), 3-pin, through-hole, with exposed tab thermally connected to output (pin 2). Mounting requires mechanical and thermal interface to heatsink.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (INPUT) | Input voltage supply connection | Accepts 2.75V to 13V DC; must be decoupled with ≥10µF capacitor near device for stability. |
| Pin 2 (OUTPUT) | Regulated output voltage node | Delivers adjustable VOUT; electrically and thermally tied to metal tab - requires isolation if heatsink is grounded. |
| Pin 3 (ADJ/GND) | Adjust terminal / reference return | Connects to voltage divider (R1–R2); referenced to OUTPUT, not system ground - defines feedback path for VOUT setting. |
Key Features
| Feature | Design Value |
|---|---|
| Fast transient response | Stabilizes within microseconds after load step changes - minimizes undershoot/overshoot on CPU core rails during burst activity. |
| Thermal shutdown protection | Activates at TJ ≥150°C and latches off until cooldown - prevents permanent damage during overload or inadequate heatsinking. |
| Current limiting | 3.1–4.3A foldback limit - protects against short-circuit faults while maintaining safe power dissipation limits. |
| Adjustable output (1.2V to 12V) | Set by external R1/R2 ratio - eliminates need for multiple fixed-voltage SKUs and supports legacy or custom voltage requirements. |
| Low output noise | 0.003% RMS (of VOUT) - avoids interference in sensitive analog or RF subsystems powered from same supply domain. |
Applications
| Pentium® Processor Core Supply | PowerPC® System Rail |
|---|---|
Use Scenario: Provides clean, regulated 2.5V or 3.3V core voltage to legacy Pentium-class CPUs in industrial control modules. IC Role / Device Role / Timing Role: Primary linear regulator delivering low-noise, tightly regulated power to CPU VCC core pins. Use Value: Maintains <±1.65mV load regulation across 0–3A, ensuring stable clocking and preventing timing violations during dynamic load transitions. |
Use Scenario: Supplies 1.8V or 2.5V I/O or memory interface rails in PowerPC-based communications equipment. IC Role / Device Role / Timing Role: Secondary LDO generating isolated, low-ripple auxiliary rail for SerDes or DDR termination networks. Use Value: 72dB ripple rejection suppresses switching noise from upstream DC/DC converters, preserving signal integrity on high-speed buses. |
| Industrial PLC Logic Supply | Embedded FPGA Configuration Rail |
Use Scenario: Powers 3.3V or 5V logic families (e.g., 74LVC, CPLDs) in programmable logic controllers operating at 0°C to 70°C ambient. IC Role / Device Role / Timing Role: Fixed or adjustable point-of-load regulator replacing inefficient 78xx series with lower dropout and better thermal performance. Use Value: 1.3V dropout enables use with 5V intermediate bus, extending operational margin and simplifying thermal management vs. legacy regulators. |
Use Scenario: Generates precise 1.2V configuration voltage for Xilinx Spartan or Intel MAX 10 FPGAs during power-up sequencing. IC Role / Device Role / Timing Role: Precision-adjustable LDO ensuring accurate VCCINT compliance during FPGA configuration and initialization. Use Value: 1.250V ±1.2% reference enables <±15mV absolute output accuracy at 1.2V - meets FPGA vendor's ±3% VCCINT tolerance requirement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM317LDR2G | 1.5A max output, 1.25V reference, TO-220 package, higher dropout (2V typ at 1.5A) | Suitable for lower-current analog rails but cannot replace LMS1587CT-ADJ/NOPB in 3A digital loads | Select when cost sensitivity outweighs current capability and dropout requirements. |
| LT1587CM-ADJ#PBF | 3A output, identical pinout and electrical specs; higher price, limited availability, no RoHS exemption | Direct functional replacement with same thermal and layout compatibility | Choose only if TI supply constraints exist and LT1587CM-ADJ#PBF sourcing is confirmed. |
Compared with LM317LDR2G, LMS1587CT-ADJ/NOPB delivers double the current and 0.7V lower dropout; versus LT1587CM-ADJ#PBF, it offers RoHS-compliant lead finish and broader distribution without sacrificing performance or footprint.
Availability
LMS1587CT-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, embedded FPGA platforms, legacy microprocessor systems, and high-reliability power supply designs requiring stable component supply and long-term manufacturability.
Supply support for LMS1587CT-ADJ/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability linear regulators and power solutions.
The LMS1587 series was designed specifically for low-voltage, high-current microprocessor core and I/O supply applications where fast transient response and thermal robustness are critical.
FAQ
What is the minimum required output capacitance for stability of the LMS1587CT-ADJ/NOPB?
The LMS1587CT-ADJ/NOPB requires a minimum 10 µF output capacitor for stability, as specified in the datasheet. Ceramic, tantalum, or aluminum electrolytic types are acceptable, but ESR must remain within 0.1–10 Ω. Using less than 10 µF risks oscillation under load transients, especially above 1A. The LMS1587CT-ADJ/NOPB datasheet Figure 1 confirms this value for the TO-220 variant.
Can the LMS1587CT-ADJ/NOPB be used in parallel for higher current capability?
No, the LMS1587CT-ADJ/NOPB is not designed for parallel operation. Its internal current limit and thermal protection are per-device, and mismatched reference voltages between units would cause unequal current sharing and potential thermal runaway. For >3A, select the LMS1585ACT-ADJ/NOPB (5A version) or use a switching regulator instead. This limitation applies to all LMS1585A/LMS1587 variants including the LMS1587CT-ADJ/NOPB.
What is the maximum input voltage rating for the LMS1587CT-ADJ/NOPB?
The absolute maximum input-to-ground voltage for the LMS1587CT-ADJ/NOPB is 13V, per the Absolute Maximum Ratings table. Exceeding this risks permanent damage even momentarily. For reliable operation, VIN should not exceed 12V continuously, and the input-output differential must stay ≥1.3V to maintain regulation at 3A. These limits are explicitly defined for the LMS1587CT-ADJ/NOPB in SNVS061G Rev. July 2013.
Does the LMS1587CT-ADJ/NOPB require a minimum load current to maintain regulation?
Yes, the LMS1587CT-ADJ/NOPB requires a minimum load current of 2.0–10.0 mA to maintain regulation, as stated in the Electrical Characteristics table under "Minimum Load Current (4)". Below this threshold, output voltage may drift or become unstable. This behavior is inherent to the LMS1587CT-ADJ/NOPB's internal bandgap and error amplifier architecture and is documented in TI's SNVS061G datasheet.
How does the ADJ pin current affect output voltage accuracy in the LMS1587CT-ADJ/NOPB?
The ADJ pin draws up to 120 µA, introducing an error term in the output voltage equation VOUT = VREF(1 + R2/R1) + IADJR2. To keep this error below 0.5%, R2 should be ≤10 kΩ when R1 = 100 Ω. This effect is quantified in the LMS1587CT-ADJ/NOPB application note (Figure 3) and confirmed in the "Adjust Pin Current" specification. Ignoring it causes measurable VOUT deviation, especially at higher setpoints.
LMS1587CT-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Tube
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 13V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 11.7V
- Voltage Dropout (Max):
- 1.3V @ 3A
- Current - Output:
- 3A
- Current - Quiescent (Iq):
- 7 mA
- Current - Supply (Max):
- 13 mA
- PSRR:
- 72dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
LMS1587CT-ADJ/NOPB FAQ
1.How can I place an order for LMS1587CT-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LMS1587CT-ADJ/NOPB 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 LMS1587CT-ADJ/NOPB reliable?
The price and inventory of LMS1587CT-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMS1587CT-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LMS1587CT-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMS1587CT-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMS1587CT-ADJ/NOPB?
LMS1587CT-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMS1587CT-ADJ/NOPB 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 LMS1587CT-ADJ/NOPB?
For technical support, including LMS1587CT-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMS1587CT-ADJ/NOPB requirements.
6.How does Aetrix verify that LMS1587CT-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LMS1587CT-ADJ/NOPB 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 LMS1587CT-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LMS1587CT-ADJ/NOPB?
All LMS1587CT-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMS1587CT-ADJ/NOPB, 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 LMS1587CT-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LMS1587CT-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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