Texas Instruments LM5008SDX/NOPB

Overview

LM5008SDX/NOPB from Texas Instruments is a 95-V, 350-mA constant on-time (COT) buck switching regulator with integrated 100-V N-channel MOSFET, internal 7-V VCC regulator, and no loop compensation required. It delivers regulated DC output from 9.5–95 V input in compact VSSOP-8 package, supporting applications such as 48-V automotive post-regulation and telecom secondary supplies.

For engineers reviewing the LM5008SDX/NOPB datasheet, LM5008SDX/NOPB pinout, LM5008SDX/NOPB application, or LM5008SDX/NOPB equivalent, key selection criteria include input voltage range (9.5–95 V), current limit threshold (0.51 A typ), FB reference (2.5 V), minimum off-time (300 ns), and thermal shutdown (165 °C).

Technical Context

The LM5008SDX/NOPB uses a hysteretic constant-on-time control architecture where on-time varies inversely with VIN, enabling near-constant operating frequency across line and load variations. Its regulation relies on a 2.5-V internal reference compared against FB voltage, with overvoltage protection triggered at 2.875 V.

It integrates a high-voltage start-up regulator (6.3 V UVLO), intelligent current-limit off-timer (programmable via RCL), bootstrap gate drive (BST–SW capacitor), and thermal shutdown with 25 °C hysteresis. The device operates in discontinuous conduction mode (DCM) at light loads and continuous conduction mode (CCM) at higher loads.

Key Specifications

Pinout & Package

LM5008SDX/NOPB is packaged in an 8-pin VSSOP (DGK) with 3.00 mm × 3.00 mm body size and exposed thermal pad (non-electrical). Pinout optimized for minimal trace length between SW, BST, and VIN to reduce switching noise and improve EMI performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5008SDX/NOPB, LM5164QDDARQ1 adds automotive qualification and EMI reduction at the cost of added complexity, while MAX17690ATP+ trades integrated FET simplicity for higher precision and frequency flexibility - neither is pin-compatible, and both require PCB redesign.

Availability

LM5008SDX/NOPB is available at Aetrix Electronics and suitable for 48-V automotive post-regulation, telecom secondary buck supplies, and industrial sensor power applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM5008SDX/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 specializing in analog, embedded processing, and power management ICs, with leadership in high-reliability industrial and automotive power solutions.

The LM5008 product line delivers high-voltage buck conversion for harsh environments - designed specifically for unregulated 24 V, 48 V, and 95 V input rails in telecom infrastructure, transportation, and factory automation.

FAQ

What is the absolute maximum input voltage rating for LM5008SDX/NOPB?

The LM5008SDX/NOPB has an absolute maximum VIN rating of 100 V, with recommended operating range from 9.5 V to 95 V. This 100-V rating accommodates transient surges common in automotive and industrial systems. Exceeding 100 V risks permanent damage, and operation above 95 V should only occur briefly during validated surge events - sustained operation above 95 V is outside specification and may degrade reliability. Always verify layout parasitics and input filtering to ensure clamping within limits.

Does LM5008SDX/NOPB require external loop compensation components?

No, LM5008SDX/NOPB does not require external loop compensation components due to its constant-on-time (COT) hysteretic control architecture. Regulation is achieved by comparing FB voltage to a 2.5-V internal reference and adjusting on-time per cycle - eliminating the need for error amplifiers, compensation networks, or phase-margin analysis. This simplifies design, reduces bill-of-materials, and improves transient response. However, FB node requires ≥25 mV ripple (via output capacitor ESR or added R3) for stable operation.

How is the output voltage programmed on LM5008SDX/NOPB?

The output voltage of LM5008SDX/NOPB is programmed using a resistive divider from VOUT to FB and from FB to RTN. The internal 2.5-V reference determines regulation point: VOUT = 2.5 × (R1 + R2) / R2, where R1 connects VOUT to FB and R2 connects FB to RTN. For example, a 10-V output uses R1 = 3.01 kΩ and R2 = 1.0 kΩ. FB bias current is only 100 nA, so resistor values can be relatively high (e.g., 100 kΩ total) to minimize quiescent current without affecting accuracy.

Can LM5008SDX/NOPB operate with no load or very light load?

LM5008SDX/NOPB requires a minimum load current of 1 mA to maintain stable operation and prevent bootstrap capacitor discharge during extended off-times. Below this threshold, the device may enter burst-mode cycling or shut down intermittently. If the application demands true zero-load operation, add a small bleed resistor across the output (e.g., 10 kΩ for 10 V → 1 mA) or use the RON/SD pin to disable the regulator during idle periods to reduce system quiescent current to 76 µA.

What thermal management considerations apply to LM5008SDX/NOPB in VSSOP-8 package?

LM5008SDX/NOPB in VSSOP-8 (DGK) has a junction-to-ambient thermal resistance (RθJA) of 139.7 °C/W. To maintain TJ ≤ 125 °C at full 350-mA load and 95-V input, PCB layout must maximize copper area under the exposed pad (though non-electrical in VSSOP), use multiple thermal vias to inner ground planes, and avoid enclosing the IC in sealed enclosures. Thermal shutdown activates at 165 °C with 25 °C hysteresis, but sustained operation above 125 °C accelerates aging - derate output current or add airflow if ambient exceeds 85 °C.