Texas Instruments LM5009SDC

Overview

LM5009SDC from Texas Instruments is a wide-input, non-synchronous buck switching regulator with integrated 100-V N-channel MOSFET, delivering up to 150 mA output current across 9.5–95 V input range, featuring 2.5-V ±2% feedback reference over –40°C to +125°C, no external loop compensation required, and switching frequency exceeding 600 kHz. It serves as a high-voltage bias supply in telecom, industrial power conversion, and LED current-source applications.

For engineers reviewing the LM5009SDC datasheet, LM5009SDC pinout, LM5009SDC application, or LM5009SDC equivalent, key selection considerations include its VIN feedforward control architecture, intelligent current limit with RCL-programmable off-time, thermal shutdown at 165°C, bootstrap gate drive implementation, and dual-package availability (VSSOP-8/WSON-8) for thermal optimization.

Technical Context

The LM5009SDC employs a constant-on-time control scheme where switch on-time is inversely proportional to VIN, enabling stable operating frequency across line and load variations without compensation components. Its regulation relies on internal 2.5-V reference comparison at FB and overvoltage protection at 2.875 V.

Current limiting uses an RCL-programmable off-timer with inverse dependence on VFB-35 µs at short-circuit (FB = 0 V), scaling down under partial overload-and integrates blanking (50–70 ns) to avoid false triggering during switch turn-on. Startup is enabled by an internal 7-V, 9.5-mA high-voltage regulator fed from VIN.

Key Specifications

Pinout & Package

LM5009SDC is available in thermally enhanced 8-pin WSON package (4.00 mm × 4.00 mm) with exposed pad for PCB ground connection to improve thermal performance. Pin functions are validated per TI SNVS402I Rev I (May 2021).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-input-voltage buck regulator applications.

Compared with LM5009SDC, LM5163RTWR offers synchronous rectification and higher current but lacks the same ultra-fast transient response due to compensation requirements, while LM5017MRX/NOPB delivers greater current headroom and precision enable control at the cost of larger footprint and higher BOM complexity.

Availability

LM5009SDC is available at Aetrix Electronics and suitable for telecom bias supplies, industrial AC-mains converters, LED current sources, and automotive 42-V system bias requiring stable component supply across extended temperature and high-voltage operating conditions.

Supply support for LM5009SDC 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 technologies, with decades of expertise in high-reliability power conversion ICs.

The LM5009SDC belongs to TI's wide-input-voltage DC/DC regulator product line, designed specifically for cost-sensitive, high-voltage industrial and telecom applications where simplicity, thermal efficiency, and transient performance are critical.

FAQ

What is the maximum input voltage rating for the LM5009SDC?

The LM5009SDC has an absolute maximum input voltage rating of 100 V, with recommended operating range from 9.5 V to 95 V. This allows direct connection to rectified 48-V AC mains or automotive 42-V systems, including transient surges up to 100 V without external clamping. The device incorporates internal protection to sustain these conditions reliably.

Does the LM5009SDC require external loop compensation components?

No, the LM5009SDC does not require external loop compensation components. Its constant-on-time control architecture, with on-time inversely proportional to VIN, eliminates the need for compensation networks. This simplifies design, reduces bill-of-materials count, and delivers ultra-fast transient response - a key advantage confirmed in TI's SNVS402I datasheet Section 7.3.1.

How is current limiting implemented in the LM5009SDC?

The LM5009SDC implements intelligent current limiting using an RCL-programmable off-timer whose duration is inversely proportional to FB voltage. At short-circuit (FB = 0 V), off-time is fixed at 35 µs; under partial overload, it scales downward - reducing foldback and improving recovery. Current limit threshold is 0.31 A typical, with blanking (50–70 ns) to prevent false triggering during switch turn-on.

What package options are available for the LM5009SDC?

The LM5009SDC is offered in two thermally optimized packages: 8-pin VSSOP (3.00 mm × 3.00 mm) and 8-pin WSON (4.00 mm × 4.00 mm) with exposed thermal pad. The WSON variant achieves R_θJB = 20.1°C/W, making it preferred for high-ambient or high-duty-cycle applications where PCB-level heat dissipation is critical to maintaining 150 mA output capability.

Can the LM5009SDC be used in constant-current LED driver configurations?

Yes, the LM5009SDC can be configured as a constant-current LED driver by connecting the FB pin to a current-sense resistor in series with the LED string. Its 2.5-V reference accuracy (±2%) and sub-5-nA FB bias current ensure stable current regulation across temperature. Designers must ensure minimum 25-mV ripple at FB and select appropriate output capacitor ESR to maintain stability per Section 7.3.1 of the datasheet.