Texas Instruments LP38852T-ADJ/NOPB

Overview

LP38852T-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, ±1.5% output voltage accuracy at 25°C, and integrated soft-start/enable functionality. It powers microcontroller cores, DSPs, and SMPS post-regulators in space-constrained industrial and computing systems.

For engineers reviewing the LP38852T-ADJ/NOPB datasheet, LP38852T-ADJ/NOPB pinout, LP38852T-ADJ/NOPB application, or LP38852T-ADJ/NOPB equivalent, key selection considerations include its 0.8–1.8 V adjustable output range, 3–5.5 V VBIAS requirement, 7-pin TO-220 package thermal performance (RθJA = 34.0°C/W), and bias-supplied gate drive architecture enabling ultra-low VIN operation.

Technical Context

The LP38852T-ADJ/NOPB uses an N-MOS pass transistor driven by a separate VBIAS rail (3–5.5 V), decoupling control circuitry power from high-current VIN path-enabling stable regulation down to VIN = VOUT + 130 mV. Its CMOS-based architecture delivers low quiescent current (7–9 mA from VIN, 3–4.5 mA from VBIAS at 1.5 A) and fast transient response without requiring large output capacitance.

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 programmable soft-start via external CSS capacitor (tSS = CSS × rSS × 5, rSS = 13.5 kΩ typical). Enable logic (VEN(ON) = 1.25 V, 100 mV hysteresis) supports controlled power sequencing.

Key Specifications

Pinout & Package

LP38852T-ADJ/NOPB is housed in a 7-pin TO-220 package (14.986 mm × 10.16 mm body) with exposed tab thermally connected to GND. The tab provides primary heat dissipation path; PCB copper pour under tab is mandatory for thermal compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and LT3080MPDE#PBF, LP38852T-ADJ/NOPB uniquely combines dual-rail ultra-low dropout, TO-220 thermal capability, and integrated sequencing features-making it optimal for high-current, space-constrained, and wide-input-range industrial LDO applications where bias rail availability exists.

Availability

LP38852T-ADJ/NOPB is available at Aetrix Electronics and suitable for ASIC core power supplies, SMPS post-regulators, DSP/FPGA core rails, and server I/O voltage rails requiring stable component supply, long-term manufacturability, and industrial temperature support.

Supply support for LP38852T-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 system solutions for industrial, automotive, and communications markets.

LP38852T-ADJ/NOPB belongs to TI's high-performance LDO family targeting high-current, low-noise, and fast-transient applications in computing and infrastructure equipment-designed specifically for core voltage regulation where dropout, accuracy, and thermal reliability are critical.

FAQ

What is the minimum input voltage required for LP38852T-ADJ/NOPB to regulate at 1.2 V output?

The LP38852T-ADJ/NOPB requires VIN ≥ VOUT + VDO. With a typical dropout voltage of 130 mV at 1.5 A, the minimum VIN is 1.2 V + 0.13 V = 1.33 V. However, VIN must also be ≤ min(VBIAS, 4.5 V), so VBIAS must be ≥1.33 V-and per spec, VBIAS must be ≥3 V for VOUT ≤1.2 V. Thus, practical minimum VIN is 1.33 V with VBIAS ≥3 V.

Can LP38852T-ADJ/NOPB operate with VBIAS = 3.3 V while delivering 1.5 V output?

No. Per the datasheet's Recommended Operating Conditions, when VOUT >1.2 V, VBIAS must be between 4.5 V and 5.5 V. At VOUT = 1.5 V and VBIAS = 3.3 V, the device may power on (if above UVLO), but output voltage accuracy, dropout, and transient response are not guaranteed-operation falls outside specified limits.

How does the SS pin function in LP38852T-ADJ/NOPB, and what capacitor value gives ~1 ms soft-start time?

The SS pin connects to an internal 13.5 kΩ resistor; soft-start time is calculated as tSS = CSS × 13.5 kΩ × 5. For tSS ≈ 1 ms, solve: CSS = 1000 µs / (13.5 kΩ × 5) ≈ 14.8 nF. A standard 15 nF capacitor yields tSS ≈ 1.01 ms. CSS must connect directly to clean GND-no other components on this node.

Is LP38852T-ADJ/NOPB stable with ceramic output capacitors smaller than 10 µF?

No. The datasheet explicitly states "Stable with 10-µF Ceramic Capacitors" and specifies minimum COUT = 10 µF in Recommended Operating Conditions. Using smaller values risks instability, excessive ringing, or failure to maintain regulation under load transients-TI does not characterize or guarantee performance below 10 µF.

What thermal derating applies to LP38852T-ADJ/NOPB in a 60°C ambient environment with no heatsink?

With RθJA = 34.0°C/W (TO-220), max allowable power dissipation at TA = 60°C is PD = (TJ(MAX) − TA) / RθJA = (125°C − 60°C) / 34.0°C/W ≈ 1.91 W. At 1.5 A output and 130 mV dropout, PD = 1.5 A × 0.13 V = 0.195 W-well within limit. Derating only becomes critical above ~4.5 A equivalent load (if VDO increased) or in higher ambient temperatures.