Texas Instruments LM2675MX-ADJ/NOPB

Overview

LM2675MX-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator IC delivering up to 1 A output current with adjustable output voltage from 1.21 V to 37 V, 260 kHz fixed-frequency operation, ±1.5% output voltage tolerance, and 90% typical efficiency at 12 V_IN/1 A. It serves as a primary power conversion stage in industrial power supplies and embedded system rails.

For engineers reviewing the LM2675MX-ADJ/NOPB datasheet, LM2675MX-ADJ/NOPB pinout, LM2675MX-ADJ/NOPB application, or LM2675MX-ADJ/NOPB equivalent, key selection criteria include its 8-pin SOIC package, internal DMOS switch, feedback-based voltage programming, thermal shutdown, and TTL-compatible ON/OFF control - all critical for compact, high-efficiency buck converter design.

Technical Context

The LM2675MX-ADJ/NOPB integrates a DMOS power MOSFET switch, internal 260 kHz oscillator, patented frequency compensation, and precision 1.21 V reference. Its feedback loop regulates output by comparing FB pin voltage against this internal reference, enabling precise external resistor-divider programming.

It operates across 8 V–40 V input range and supports active mode (ON/OFF ≥ 1.4 V) and low-power shutdown mode (ON/OFF ≤ 1.4 V, 50 μA standby). Protection includes cycle-by-cycle current limiting (1.25–2.1 A), thermal shutdown, and overvoltage-safe bootstrapping via CB pin.

Key Specifications

Pinout & Package

LM2675MX-ADJ/NOPB is packaged in an 8-pin SOIC (D package), 4.9 mm × 6 mm body size, with exposed pad not present (non-WSON variant). Pin functions are validated per TI SNVS129G Rev G.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with LM2675MX-ADJ/NOPB, LM2678-5.0/NOPB offers identical performance in fixed-output use cases with zero component changes, while TPS54202DRCT provides higher current and integration at the cost of layout complexity and non-drop-in replacement.

Availability

LM2675MX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded system rail generation, and preregulator applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM2675MX-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 technologies, with decades of expertise in high-reliability power conversion ICs.

The LM2675 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, minimal external component count, and robust operation in industrial and embedded power applications.

FAQ

What is the minimum input voltage required for stable operation of the LM2675MX-ADJ/NOPB?

The LM2675MX-ADJ/NOPB requires a minimum input voltage of 6.5 V under recommended operating conditions. Below this threshold, regulation cannot be maintained - especially when programmed for higher output voltages where duty cycle approaches 100%. For example, generating 12 V output demands VIN ≥ 15 V to ensure sufficient headroom. Always verify minimum VIN against target VOUT and worst-case duty cycle in your design.

How do I calculate the feedback resistor values for a desired output voltage with the LM2675MX-ADJ/NOPB?

To set output voltage with LM2675MX-ADJ/NOPB, use R2 = 10 kΩ (recommended value) and calculate R1 = R2 × (V_OUT/1.21 V − 1). For instance, for 3.3 V output: R1 = 10 kΩ × (3.3/1.21 − 1) ≈ 17.4 kΩ. The FB pin bias current is only 85 nA, so resistor values between 10 kΩ and 100 kΩ maintain accuracy without excessive power loss or noise sensitivity.

Does the LM2675MX-ADJ/NOPB require an external bootstrap capacitor, and what value is recommended?

Yes, the LM2675MX-ADJ/NOPB requires a bootstrap capacitor connected between CB (Pin 1) and VSW (Pin 8) to drive the internal high-side DMOS gate. TI specifies a 470 nF ceramic capacitor rated for ≥16 V. This value ensures sufficient charge transfer during each switching cycle to maintain gate voltage above threshold, especially at high duty cycles or elevated temperatures.

Can the LM2675MX-ADJ/NOPB be used in discontinuous conduction mode (DCM), and how does it affect performance?

Yes, the LM2675MX-ADJ/NOPB operates in both continuous (CCM) and discontinuous (DCM) conduction modes depending on load and inductor value. At light loads (<300 mA), DCM reduces switching losses and improves light-load efficiency. However, DCM introduces higher output voltage ripple and slower transient response. Figure 5-16 in the datasheet shows measured waveforms confirming stable DCM behavior with appropriate L and C selection.

What thermal considerations apply to the LM2675MX-ADJ/NOPB in SOIC-8 package at full 1 A load?

In SOIC-8 (D package), the LM2675MX-ADJ/NOPB has R_θJA = 105°C/W. At 1 A output into 5 V (5 W), with 10% power loss (0.5 W), junction temperature rise is ~52.5°C above ambient. With 25°C ambient, T_J ≈ 77.5°C - well within the 125°C max rating. TI confirms that PCB copper traces alone serve as adequate heatsinking; no additional heatsink is required if ≥1 in² of 2-oz copper is connected to GND pins.