Texas Instruments LP3984IMF-1.8

Overview

LP3984IMF-1.8 from Texas Instruments is a micropower, ultra-low-dropout CMOS voltage regulator delivering 1.8 V at up to 150 mA from a 2.5–6.0 V input, featuring 75 mV typical dropout at full load, ≤1.2 µA shutdown current, and fast 20 µs turn-on time - designed for space-constrained battery-powered RF subsystems in cellular handsets.

For engineers reviewing the LP3984IMF-1.8 datasheet, LP3984IMF-1.8 pinout, LP3984IMF-1.8 application, or LP3984IMF-1.8 equivalent, key selection considerations include its SOT-23-5 package compatibility, 1 µF tantalum output capacitor support, 60 dB PSRR at 1 kHz, −40°C to +125°C operating range, and logic-controlled enable with VIH = 1.4 V / VIL = 0.4 V thresholds.

Technical Context

The LP3984IMF-1.8 employs a CMOS pass transistor architecture optimized for minimal quiescent current across load and input voltage variations, maintaining stable regulation down to 2.5 V input while increasing ground current only slightly in dropout. Its internal bandgap reference and error amplifier deliver ±1.2% initial output voltage tolerance over temperature.

It integrates thermal shutdown (160°C trip, 20°C hysteresis) and short-circuit current limiting (600 mA steady-state), with power supply rejection exceeding 60 dB at 1 kHz and sustaining 40 dB at 10 kHz - critical for noise-sensitive RF and baseband power domains in CDMA/GSM handsets.

Key Specifications

Pinout & Package

SOT-23-5 package (TI package code DBV), 2.9 mm × 1.6 mm footprint, 1.45 mm height, JEDEC-compliant lead finish (CuSn), moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with TPL720F18 and MCP1700T-1802E/MB, the LP3984IMF-1.8 uniquely balances wide-input-range operation (2.5 V min), integrated enable, and proven tantalum-stability - making it the preferred choice for legacy and cost-optimized cellular RF power domains.

Availability

LP3984IMF-1.8 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable information appliance development, and industrial handheld instrumentation requiring stable component supply with long-term lifecycle visibility.

Supply support for LP3984IMF-1.8 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 connectivity technologies, with over 50 years of innovation in power management ICs.

The LP3984IMF-1.8 belongs to TI's micropower LDO family engineered specifically for space- and power-constrained portable wireless systems - emphasizing ultra-low IQ, fast transient response, and robust capacitor compatibility.

FAQ

What is the maximum input voltage rating for the LP3984IMF-1.8?

The LP3984IMF-1.8 has an absolute maximum input voltage of 6.5 V, but its recommended operating input range is 2.5 V to 6.0 V. Exceeding 6.5 V risks permanent damage per the Absolute Maximum Ratings table. The LP3984IMF-1.8 maintains regulation and specified PSRR performance across the full 2.5–6.0 V range, making it ideal for single-cell Li-ion and multi-cell alkaline applications.

Does the LP3984IMF-1.8 require an external bypass capacitor?

No, the LP3984IMF-1.8 does not require an external bypass capacitor. Unlike some LDOs with noise-reduction pins, the LP3984IMF-1.8 uses an internal bandgap reference and error amplifier architecture that achieves 90 µV_RMS output noise with only a 1 µF tantalum output capacitor. Adding external capacitance beyond the specified 1–22 µF output range may degrade stability or transient response.

Can the LP3984IMF-1.8 be used with ceramic output capacitors?

The LP3984IMF-1.8 is explicitly characterized and guaranteed stable with 1–22 µF tantalum capacitors having 2–10 Ω ESR. While ceramic capacitors may function in some lab conditions, TI does not validate or guarantee stability with ceramics due to their near-zero ESR, which can cause oscillation. For production use, the LP3984IMF-1.8 must be paired with a tantalum or polymer capacitor meeting the ESR specification.

What is the thermal resistance (θ_JA) of the LP3984IMF-1.8 in its SOT-23-5 package?

The LP3984IMF-1.8 in the SOT-23-5 (DBV) package has a junction-to-ambient thermal resistance (θ_JA) of 220°C/W under standard JEDEC test conditions. This value assumes a 1-inch² copper pad on a 1-layer board. With proper PCB layout - including thermal vias and extended copper pour - actual θ_JA can improve significantly, allowing higher continuous output current before thermal shutdown activates at 160°C.

Is the LP3984IMF-1.8 RoHS compliant and lead-free?

Yes, the LP3984IMF-1.8/NOPB variant is RoHS compliant and lead-free, with Green (RoHS & no Sb/Br) eco-plan designation and CuSn lead finish. It meets JEDEC MSL Level-1 (unlimited floor life at ≤30°C/60% RH) and is qualified for reflow soldering at 260°C peak. The "NOPB" suffix explicitly confirms Pb-free compliance per TI's packaging addendum dated August 2016.