Texas Instruments LP38841T-1.2/LF03

Overview

LP38841T-1.2/LF03 from Texas Instruments is a 1.2V, 0.8A ultra-low-dropout linear regulator in TO-220-5 package, featuring 75mV dropout at full load, ±1.5% initial output accuracy, and stable operation with ceramic output capacitors ≥22µF. It employs dual-rail architecture (VIN + VBIAS) to enable regulation from inputs as low as ~1.3V and is used in FPGA core supplies and SMPS post-regulation.

For engineers reviewing the LP38841T-1.2/LF03 datasheet, LP38841T-1.2/LF03 pinout, LP38841T-1.2/LF03 application, or LP38841T-1.2/LF03 equivalent, key selection criteria include dropout voltage under 0.8A load, bias rail dependency (4.5–5.5V), shutdown quiescent current (<0.06µA), thermal resistance (θ_J-A = 65°C/W, no heatsink), and compatibility with ceramic vs. tantalum output capacitors.

Technical Context

The LP38841T-1.2/LF03 uses an N-MOS pass transistor driven by a separate VBIAS rail (4.5–5.5V), enabling ultra-low dropout while maintaining high bandwidth and fast transient response. Its CMOS-based control circuitry draws only 2mA quiescent current from VBIAS and 30mA from VIN at full load.

Stability is achieved via external capacitor selection: minimum 22µF ceramic or 4.7µF tantalum on VOUT, 10µF ceramic on VIN, and 0.1µF on VBIAS. The device integrates over-temperature and over-current protection, with junction temperature rated from −40°C to +125°C.

Key Specifications

Pinout & Package

LP38841T-1.2/LF03 is housed in a 5-lead TO-220 package (NDH variant) with exposed tab electrically connected to GND. Pin 3 and the metal tab are both ground terminals and must be tied together on PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and LP3985IM5-1.2/NOPB, the LP38841T-1.2/LF03 uniquely balances high current (0.8A), ultra-low dropout (75mV), and dual-rail flexibility-making it optimal for systems with constrained input voltage and available 5V bias rail, unlike the single-supply alternatives.

Availability

LP38841T-1.2/LF03 is available at Aetrix Electronics and suitable for FPGA core supplies, server I/O rails, ASIC power delivery, and SMPS post-regulation requiring stable component supply across industrial temperature range (−40°C to +125°C).

Supply support for LP38841T-1.2/LF03 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.

The LP38841 series was designed specifically for high-current, ultra-low-dropout applications in computing and communications infrastructure-where fast transient response, ceramic capacitor compatibility, and dual-rail flexibility are essential.

FAQ

What is the minimum input voltage required for LP38841T-1.2/LF03 to regulate 1.2V output?

The LP38841T-1.2/LF03 requires a minimum input voltage of approximately 1.275V (1.2V + 75mV typical dropout) at 0.8A load. However, this assumes VBIAS is properly supplied at 4.5–5.5V. Without valid VBIAS, the device will not operate-even if VIN exceeds VOUT + VDO-due to lack of gate drive for the N-MOS pass transistor. Always verify VBIAS presence before evaluating VIN margin.

Can LP38841T-1.2/LF03 operate without the VBIAS supply?

No, LP38841T-1.2/LF03 cannot operate without VBIAS. The VBIAS pin supplies gate drive voltage to the internal N-MOS pass transistor and powers the control circuitry. If VBIAS is missing or below ~4V, the device enters under-voltage lockout and disables output regardless of VIN level. A stable 4.5–5.5V bias rail is mandatory for functional operation of LP38841T-1.2/LF03.

What output capacitor value is required for stable operation of LP38841T-1.2/LF03?

LP38841T-1.2/LF03 requires ≥22µF X7R or X5R ceramic capacitor on the OUTPUT pin for guaranteed stability. Tantalum capacitors may be used at ≥4.7µF, but ceramic is preferred for lower ESR, better temperature stability, and reduced aging. Z5U/Y5V dielectrics are prohibited-they lose >80% capacitance at operating voltage/temperature and risk instability.

Does LP38841T-1.2/LF03 have built-in thermal protection?

Yes, LP38841T-1.2/LF03 includes integrated thermal shutdown protection. When junction temperature exceeds ~150°C, the device disables output until temperature falls below the hysteresis threshold (~140°C). This protects against permanent damage during sustained overload or inadequate heatsinking. Thermal derating must still be calculated using θ_J-A = 65°C/W (TO-220, no heatsink) per the datasheet.

Is LP38841T-1.2/LF03 RoHS compliant?

Yes, LP38841T-1.2/LF03 is RoHS compliant. Per TI's Package Option Addendum, the part carries "Yes" in the RoHS column and uses Sn (tin) lead finish. It meets JEDEC Level-1 moisture sensitivity requirements and is qualified for reflow soldering up to 245°C peak temperature. The NDH package variant is fully compatible with standard lead-free assembly processes.