Texas Instruments LM2587S-5.0/NOPB

Overview

LM2587S-5.0/NOPB from Texas Instruments is a monolithic 5-A step-up (boost) and flyback switching regulator IC with fixed 5.0-V output, 100-kHz fixed-frequency oscillator, 4-V to 40-V input range, NPN internal switch rated for 65-V standoff and 5-A peak current, and ±4% system output voltage tolerance over line and load. It enables compact, low-component-count DC-DC conversion in industrial power supplies and battery-powered systems.

For engineers reviewing the LM2587S-5.0/NOPB datasheet, LM2587S-5.0/NOPB pinout, LM2587S-5.0/NOPB application, or LM2587S-5.0/NOPB equivalent, key selection considerations include its fixed 5-V output configuration, TO-263-5 (DDPAK) thermal performance, current-mode control architecture for transient response, integrated soft-start, and undervoltage lockout with thermal shutdown protection.

Technical Context

The LM2587S-5.0/NOPB implements current-mode PWM control using an internal 100-kHz oscillator and cycle-by-cycle current limiting. Its error amplifier compares feedback voltage against a precision 5.0-V reference (measured at FB pin), generating a compensation signal that modulates switch on-time via a comparator driven by a ramp proportional to inductor current.

It integrates a 5-A NPN power switch with 65-V V_CEO rating, protected by thermal shutdown, undervoltage lockout (3.3 V threshold), and internal current limit (6.5 A typical). The device supports both boost and flyback topologies without external timing components, relying on fixed-frequency operation and internal soft-start (11 µA soft-start current) to manage in-rush.

Key Specifications

Pinout & Package

LM2587S-5.0/NOPB is housed in a thermally enhanced 5-pin DDPAK/TO-263 (KTT) package (10.16 mm × 8.42 mm body), with exposed drain pad soldered to PCB for optimal heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up/flyback regulator applications.

Compared with LM2587T-5.0/NOPB, LM2587S-5.0/NOPB delivers superior thermal management in SMT layouts, while versus LM2577-5.0/NOPB it provides higher current capability, faster switching, and enhanced protection features-making it the preferred choice for demanding 5-V industrial and automotive power rails.

Availability

LM2587S-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, automotive auxiliary rails, and medical portable equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM2587S-5.0/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.

The LM2587 series was designed specifically for cost-sensitive, high-reliability flyback, boost, and forward converter applications where minimal external components, integrated protection, and wide input voltage range are critical.

FAQ

What topology does the LM2587S-5.0/NOPB support?

The LM2587S-5.0/NOPB supports flyback, step-up (boost), and forward converter topologies. Its internal 5-A NPN switch, 100-kHz oscillator, and current-mode control architecture enable all three configurations using discrete external components. For boost operation, it requires an inductor, diode, and output capacitor; for flyback, a transformer replaces the inductor. The LM2587S-5.0/NOPB datasheet includes reference schematics for each topology.

Does the LM2587S-5.0/NOPB require external feedback resistors?

No, the LM2587S-5.0/NOPB does not require external feedback resistors. It is a fixed 5.0-V output variant with the feedback divider integrated internally. The FB pin is internally connected to the 5.0-V reference, eliminating the need for external resistors and reducing component count and layout sensitivity. This differs from the adjustable LM2587-ADJ version, which requires external resistors to set output voltage.

What is the maximum continuous output current achievable with LM2587S-5.0/NOPB?

The LM2587S-5.0/NOPB supports up to 5-A peak switch current, but continuous output current depends on topology, input voltage, and thermal design. In boost configuration, output current is externally limited to prevent switch damage; typical continuous output is 1.45 A at 12 V_IN (per datasheet Section 6.6). In flyback mode, internal current limiting applies, enabling higher continuous outputs-up to 1.75 A at 12 V_IN-with proper transformer and PCB thermal management.

How does the soft-start function work in LM2587S-5.0/NOPB?

The LM2587S-5.0/NOPB implements soft-start via a 11 µA (typical) current source charging the compensation (COMP) pin capacitor. This gradually increases the COMP voltage, ramping up the duty cycle and limiting in-rush current during startup. Soft-start duration is determined by the external RC network on COMP; typical values (e.g., 10 nF + 100 kΩ) yield ~10-ms ramp. This prevents input rail sag and output overshoot, especially critical in battery-powered systems.

Is LM2587S-5.0/NOPB RoHS-compliant and lead-free?

Yes, LM2587S-5.0/NOPB is RoHS-compliant and lead-free. The "/NOPB" suffix explicitly denotes lead-free packaging per TI's product marking convention. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) 3 and is qualified for reflow soldering per IPC/JEDEC J-STD-020. Full compliance documentation-including RoHS, REACH, and conflict minerals statements-is available on Texas Instruments' official product page for LM2587S-5.0/NOPB.