Texas Instruments LP38852SX-ADJ/NOPB

Overview

LP38852SX-ADJ/NOPB from Texas Instruments is a 1.5-A adjustable low-dropout linear regulator with dual-rail operation (VIN and VBIAS), 130-mV typical dropout at full load, ±2% output voltage accuracy over –40°C to +125°C, and programmable soft-start. It powers microcontroller cores, DSPs, and SMPS post-regulators where ultra-low VIN and fast transient response are critical.

For engineers reviewing the LP38852SX-ADJ/NOPB datasheet, LP38852SX-ADJ/NOPB pinout, LP38852SX-ADJ/NOPB application, or LP38852SX-ADJ/NOPB equivalent, key selection considerations include its dual-supply architecture (VIN/VBIAS), bias-dependent operating range (3–5.5 V), 7-pin DDPAK/TO-263 package thermal performance (RθJA = 34.3°C/W), and soft-start timing dependency on external CSS capacitor.

Technical Context

The LP38852SX-ADJ/NOPB uses an N-MOS pass transistor driven by a separate VBIAS rail, enabling stable regulation down to VIN = VOUT + 130 mV while maintaining low quiescent current (7–9 mA from VIN, 3–4.5 mA from VBIAS). Its internal reference (0.6 V) and ADJ pin feedback allow precise output setting from 0.8 V to 1.8 V via external resistor divider.

It integrates undervoltage lockout (UVLO threshold ≈2.45 V, 150-mV hysteresis), thermal shutdown (160°C), overcurrent protection (4.5-A short-circuit limit), and enable-controlled sequencing. Soft-start is implemented via internal 13.5-kΩ SS pin resistance charging external CSS, yielding tSS = CSS × 13.5 kΩ × 5.

Key Specifications

Pinout & Package

LP38852SX-ADJ/NOPB is packaged in a 7-pin DDPAK/TO-263 (KTW) with exposed thermal tab (electrically connected to GND). The package measures 10.10 mm × 8.89 mm and provides RθJA = 34.3°C/W, enabling 1.5-A operation without forced airflow when properly mounted to copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP38852SX-ADJ/NOPB, TPS7A8300RGRT offers lower output noise but sacrifices ultralow dropout and dual-rail flexibility; neither part is pin-compatible, and both require distinct PCB layouts and external component sets.

Availability

LP38852SX-ADJ/NOPB is available at Aetrix Electronics and suitable for ASIC power supplies, server core/I/O rails, and DSP/FPGA core voltage regulation requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LP38852SX-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 company designing analog ICs, embedded processors, and digital signal solutions for industrial, automotive, and communications markets.

The LP38852SX-ADJ/NOPB belongs to TI's high-performance LDO family targeting high-current, low-noise, fast-transient applications in computing and infrastructure systems where precision regulation and thermal robustness are essential.

FAQ

What is the minimum input voltage required for LP38852SX-ADJ/NOPB to regulate a 0.8-V output?

The LP38852SX-ADJ/NOPB requires VIN ≥ VOUT + VDO. With a typical dropout voltage of 130 mV at 1.5-A load, the minimum VIN is 0.93 V. This ultralow headroom is enabled by the separate VBIAS rail powering the control circuitry independently of the high-current VIN path.

Can LP38852SX-ADJ/NOPB operate with VBIAS = 3.3 V while delivering 1.5 V at the output?

No. Per the datasheet, when VOUT > 1.2 V, VBIAS must be between 4.5 V and 5.5 V to ensure proper gate drive and regulation. At VBIAS = 3.3 V, the device may not sustain 1.5-V output under full load or across temperature, risking instability or dropout.

How does the SS pin function in LP38852SX-ADJ/NOPB, and what capacitor value sets a 2-ms soft-start time?

The SS pin sources current through an internal 13.5-kΩ resistor to charge an external CSS capacitor. Soft-start time is calculated as tSS = CSS × 13.5 kΩ × 5. For tSS = 2 ms, CSS = 2,000 µs / (13.5 kΩ × 5) ≈ 29.6 nF-use a standard 30-nF ceramic capacitor rated for ≥6.3 V.

Does LP38852SX-ADJ/NOPB require an external compensation capacitor like traditional LDOs?

No. The LP38852SX-ADJ/NOPB is internally compensated and stable with only a 10-µF ceramic output capacitor. Its CMOS N-MOS architecture provides wide bandwidth without external CFF, though a feedforward capacitor (CFF) is recommended on the ADJ node for optimal transient response across the full VOUT range.

What thermal derating applies to LP38852SX-ADJ/NOPB in a 7-pin DDPAK package at 1.5-A load?

In the 7-pin DDPAK (KTW) package, RθJA = 34.3°C/W. At 1.5-A load with 130-mV dropout, power dissipation is ~195 mW. Junction temperature rise is 195 mW × 34.3°C/W ≈ 6.7°C above ambient. With TJ(max) = 125°C, this allows operation up to ~118°C ambient-no derating needed below that threshold.