Texas Instruments LP3985ITL-4.8

Overview

LP3985ITL-4.8 from National Semiconductor is a micropower, 150mA ultra-low-noise, ultra-low-dropout CMOS voltage regulator optimized for battery-powered portable wireless systems. It delivers 4.8V output from 2.5–6.0V input, achieves ≤100mV dropout at 150mA load, consumes ≤1.5µA in shutdown, and maintains 30µV_rms output noise (10Hz–100kHz) with optional 0.01µF bypass capacitor - enabling clean power for RF front-ends and precision analog circuits in space-constrained handsets.

For engineers reviewing the LP3985ITL-4.8 datasheet, LP3985ITL-4.8 pinout, LP3985ITL-4.8 application, or LP3985ITL-4.8 equivalent, key selection considerations include its 5-bump thin micro SMD (TLA05) package, logic-controlled enable with 0.4V/1.4V thresholds, thermal shutdown and short-circuit protection, and guaranteed stability with 1µF ±30% ceramic output capacitors - critical for high-density mobile PCB layouts.

Technical Context

The LP3985ITL-4.8 employs a CMOS pass transistor architecture to achieve ultra-low quiescent current and minimal dropout voltage across its full operating range. Its bandgap reference includes an internal 70µA pre-charge current source for the BYPASS pin, enabling fast 200µs turn-on while preserving low-noise performance.

Power supply rejection exceeds 50dB at 1kHz under VIN = VOUT + 0.2V conditions and remains effective down to low input voltages typical of discharging Li-ion batteries. Output regulation tolerances are ±3% over −40°C to +125°C junction temperature, with load regulation error as low as 0.0004%/mA in micro SMD variants.

Key Specifications

Pinout & Package

LP3985ITL-4.8 uses the thin micro SMD (TLA05) package: 5-bump, 1.006mm × 1.463mm footprint, 0.6mm height, non-solder-mask-defined (NSMD) pads per AN-1112. JEDEC-compliant pin numbering applies.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise LDO applications.

Compared with XC6206P482MR and RP108L481B-TR, LP3985ITL-4.8 uniquely combines JEDEC-standardized micro SMD footprint, dedicated BYPASS pin for configurable noise filtering, and guaranteed 30µV_rms performance - making it optimal for ultra-dense RF modules where noise, size, and enable timing are co-constrained.

Availability

LP3985ITL-4.8 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable medical instrumentation, industrial handheld terminals, and battery-powered IoT edge nodes requiring stable component supply with long lifecycle visibility.

Supply support for LP3985ITL-4.8 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

National Semiconductor was a U.S.-based analog semiconductor pioneer, acquired by Texas Instruments in 2011, known for high-performance power management and data conversion ICs.

The LP3985 series was designed specifically for space- and power-constrained portable wireless devices, emphasizing micropower operation, ultra-low noise, and minimal PCB footprint - targeting cellular handsets, PDAs, and handheld test equipment.

FAQ

What is the maximum dropout voltage specification for LP3985ITL-4.8 at full 150mA load?

The LP3985ITL-4.8 has a maximum dropout voltage of 100mV when delivering 150mA output current, measured as the input-to-output differential required to maintain VOUT within 100mV of its nominal 4.8V value. This specification is guaranteed over the full −40°C to +125°C junction temperature range and enables efficient operation even as input voltage declines near battery exhaustion.

Does LP3985ITL-4.8 require an external bypass capacitor to achieve its specified 30µVrms output noise?

Yes - the 30µV_rms output noise figure (10Hz–100kHz) for LP3985ITL-4.8 is achieved only when a 0.01µF NPO or COG ceramic capacitor is connected between the BYPASS pin and ground. Without this capacitor, output noise increases significantly; the BYPASS node interfaces directly with the bandgap reference, and the capacitor provides low-impedance shunting of high-frequency noise without affecting transient response.

What package type and dimensions does LP3985ITL-4.8 use, and what assembly guidance applies?

LP3985ITL-4.8 uses the thin micro SMD (TLA05) package: 5-bump, 1.006mm × 1.463mm body size, 0.6mm height, with NSMD (non-solder-mask-defined) copper pads. Per National Semiconductor Application Note AN-1112, assembly requires precise stencil design, controlled reflow profile, and alignment ordinals on the PCB to ensure accurate placement - critical due to the absence of leads and fine pitch.

Can LP3985ITL-4.8 operate stably with a 0.7µF output capacitor, and what capacitor characteristics are mandatory?

Yes - LP3985ITL-4.8 is stable with a minimum 0.7µF output capacitor, provided it meets ±30% tolerance over temperature and has ESR between 5mΩ and 500mΩ. X7R dielectric ceramic capacitors are strongly recommended to maintain capacitance across −40°C to +125°C; Y5V or Z5U types are discouraged due to excessive drift. The capacitor must be placed within 1cm of the VOUT pin and connected to a clean analog ground.

What are the enable voltage thresholds and shutdown current for LP3985ITL-4.8?

LP3985ITL-4.8 asserts enable when VEN exceeds 1.4V (VIH) and disables when VEN falls below 0.4V (VIL), with guaranteed operation across 2.5–6.0V input range. In shutdown mode, the device draws ≤1.5µA total quiescent current - verified over temperature - making it suitable for systems requiring ultra-low standby power, such as always-on sensor wake-up circuits.