Texas Instruments LMS1587CSX-1.5/NOPB

Overview

LMS1587CSX-1.5/NOPB from Texas Instruments is a fixed-output 1.5V, 3A low-dropout linear regulator in DDPAK/TO-263 (KTT) package. It delivers fast transient response, 1.2V typical dropout at 3A, ±1.5% output voltage accuracy over load and temperature, and integrates thermal shutdown and current limiting. It powers microprocessor core supplies where stable low-voltage bias and high PSRR are required.

For engineers reviewing the LMS1587CSX-1.5/NOPB datasheet, LMS1587CSX-1.5/NOPB pinout, LMS1587CSX-1.5/NOPB application, or LMS1587CSX-1.5/NOPB equivalent, key selection criteria include dropout voltage at full load, thermal resistance (0.65°C/W junction-to-case), ripple rejection (60 dB at 120 Hz), minimum input voltage margin (≥3V), and compatibility with 10 µF tantalum output capacitance for stability.

Technical Context

The LMS1587CSX-1.5/NOPB uses an internal zener-trimmed bandgap reference and NPN pass transistor architecture to achieve low dropout and fast load transient recovery. Its control loop is optimized for stability with ≥10 µF output capacitance and includes built-in foldback current limiting that activates at 3.1 A (min) under overcurrent conditions.

Thermal regulation is specified at 0.003%/W, and quiescent current remains tightly controlled at 7–13 mA across input voltages from 3V to 7V. The device operates across 0°C to 125°C ambient, with junction temperature limited to 150°C and absolute maximum input-to-ground voltage of 13V.

Key Specifications

Pinout & Package

Package: DDPAK/TO-263 (KTT), 3-pin surface-mount with exposed thermal pad. Requires soldering to PCB copper pour for thermal performance; vias under pad recommended per TI SLMA002/SLMA004 guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with LM1085IT-1.5/NOPB, LMS1587CSX-1.5/NOPB offers lower dropout and superior thermal performance in surface-mount form; versus TPS7A4701RGWR, it trades ultra-low noise for higher current and fixed 1.5 V output-making it optimal for digital core supply rather than precision analog bias.

Availability

LMS1587CSX-1.5/NOPB is available at Aetrix Electronics and suitable for Pentium® processor supplies, PowerPC® logic rails, and low-voltage FPGA configuration requiring stable component supply, long-term production continuity, and RoHS-exempt compliance for industrial applications.

Supply support for LMS1587CSX-1.5/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 and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.

The LMS1587 series was designed specifically for high-current, low-dropout regulation in microprocessor and digital logic applications-emphasizing fast transient response, integrated protection, and thermal efficiency in compact surface-mount packages.

FAQ

What is the minimum input voltage required for LMS1587CSX-1.5/NOPB to maintain regulation at 3 A?

The LMS1587CSX-1.5/NOPB requires a minimum input voltage of 2.65 V (1.5 V + 1.15 V dropout) to sustain regulation at 3 A load. However, TI specifies 3 V minimum input in datasheet conditions to ensure margin across temperature and process variation. Operating below 3 V risks dropout and output collapse under worst-case conditions.

Can LMS1587CSX-1.5/NOPB be used with ceramic output capacitors instead of tantalum?

Yes, LMS1587CSX-1.5/NOPB supports ceramic output capacitors, but requires careful selection: ≥10 µF X7R/X5R with ESR ≥5 mΩ to ensure phase margin. TI recommends verifying stability via load-step testing, as low-ESR ceramics may cause ringing if not damped. The datasheet specifies 10 µF tantalum as minimum for guaranteed stability.

Does LMS1587CSX-1.5/NOPB require an input capacitor, and what value is recommended?

Yes, LMS1587CSX-1.5/NOPB requires an input capacitor for EMI suppression and source impedance control. TI recommends ≥10 µF aluminum or tantalum capacitor placed within 10 mm of VIN and GND pins. Ceramic capacitors (e.g., 1 µF X7R) may be added in parallel for high-frequency bypass, but cannot replace the bulk input cap.

What is the thermal pad soldering requirement for LMS1587CSX-1.5/NOPB in DDPAK package?

The exposed thermal pad of LMS1587CSX-1.5/NOPB must be soldered to a minimum 100 mm² copper pour on the PCB, preferably with ≥4 thermal vias (0.3 mm diameter) filled or tented. Per TI SLMA002, this achieves the rated 0.65°C/W θ_JC; omitting the pad increases junction temperature by >40°C at 3 A, risking thermal shutdown.

Is LMS1587CSX-1.5/NOPB pin-compatible with LMS1585ACSX-1.5/NOPB?

No, LMS1587CSX-1.5/NOPB is not pin-compatible with LMS1585ACSX-1.5/NOPB. Both use DDPAK/TO-263 (KTT) package and share identical pinout (VIN–VOUT–GND), but LMS1585A delivers 5 A vs. 3 A for LMS1587. Substituting without verifying thermal design and current capability may cause overheating or premature failure.