Texas Instruments LP3986BL-2528

Overview

LP3986BL-2528 from National Semiconductor is a dual ultra-low-dropout CMOS voltage regulator delivering 150 mA per channel with fixed 2.5 V and 2.8 V outputs, optimized for space-constrained battery-powered systems such as GSM/CDMA handsets. It features 60 mV typical dropout at full load, 40 µVrms output noise, 115 µA ground current, and operates across −40°C to +125°C.

For engineers reviewing the LP3986BL-2528 datasheet, LP3986BL-2528 pinout, LP3986BL-2528 application, or LP3986BL-2528 equivalent, key selection criteria include dual independent enable control, micro SMD package footprint (1.55 mm × 1.55 mm), low-noise performance with optional 0.01 µF bypass capacitor, and guaranteed stability with 1 µF ceramic output capacitors.

Technical Context

The LP3986BL-2528 integrates two independent LDO regulators sharing a common input (VIN) but with separate enable inputs (EN1, EN2) and output pins (VOUT1 = 2.5 V, VOUT2 = 2.8 V). Each regulator uses a CMOS pass device and bandgap reference with active bypass capacitor charging for fast turn-on (200 µs).

It maintains >60 dB PSRR at 1 kHz and >50 dB at 10 kHz while operating from 2.7 V to 6 V input, with crosstalk rejection of −60 dB between channels. Thermal shutdown and current limiting protect both regulators under fault conditions.

Key Specifications

Pinout & Package

LP3986BL-2528 uses an 8-bump micro SMD package (NS package BLA08CCC, 1.55 mm × 1.55 mm, 0.995 mm thickness) with bottom-side solder bumps and JEDEC-compliant pin numbering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3986BL-2528, TPL720F2528 offers higher current and lower dropout but sacrifices noise performance and bypass flexibility, while TPS7992528 trades off noise and capacitor size for broader thermal protection-making LP3986BL-2528 optimal for compact, noise-critical dual-rail RF applications.

Availability

LP3986BL-2528 is available at Aetrix Electronics and suitable for GSM handsets, CDMA modems, portable information appliances, Bluetooth headsets, and other battery-powered wireless devices requiring stable component supply with tight voltage regulation and minimal board space.

Supply support for LP3986BL-2528 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 company acquired by Texas Instruments in 2011, known for precision power management and data conversion ICs.

The LP3986 family was designed specifically for ultra-compact, low-noise dual-rail power in cellular handsets and portable wireless equipment-prioritizing micropower operation, micro SMD integration, and RF-friendly noise performance.

FAQ

What are the exact output voltages of the LP3986BL-2528?

The LP3986BL-2528 provides two fixed, factory-trimmed output voltages: VOUT1 = 2.5 V ±3% and VOUT2 = 2.8 V ±3%, specified over −40°C to +125°C junction temperature. These values are laser-trimmed during production and do not require external feedback resistors. The "2528" suffix in LP3986BL-2528 explicitly denotes this dual-voltage configuration.

Does the LP3986BL-2528 require external capacitors, and what are the minimum values?

Yes, the LP3986BL-2528 requires an input capacitor (≥1 µF ceramic) and output capacitors (≥1 µF ceramic per rail, up to 22 µF). A 0.01 µF ceramic capacitor on the BYPASS pin is strongly recommended to achieve 40 µVrms output noise. All capacitors must be placed within 1 cm of their respective pins and connected to a clean analog ground plane to ensure stability and low noise.

How does the enable functionality work on the LP3986BL-2528?

The LP3986BL-2528 has two independent enable inputs: EN1 controls VOUT1 (2.5 V) and EN2 controls VOUT2 (2.8 V). Each enables when driven to ≥1.4 V (VIH) and disables when ≤0.4 V (VIL). Both regulators enter ultra-low 1 nA shutdown current when their respective EN pins are low. This allows flexible power sequencing-for example, enabling VOUT1 first for baseband initialization before powering VOUT2 for RF activation.

What is the thermal performance and maximum power dissipation of the LP3986BL-2528?

The LP3986BL-2528 has a junction-to-ambient thermal resistance (θJA) of 220°C/W in its micro SMD package. Its maximum continuous power dissipation is 250 mW under operating conditions (−40°C to +125°C), derating by 4.5 mW/°C above 70°C ambient. At 150 mA load per rail and 60 mV dropout, total power dissipation is ~18 mW-well within safe limits even in sealed handheld enclosures.

Is the LP3986BL-2528 compatible with ceramic output capacitors having high temperature coefficient dielectrics like Y5V?

The LP3986BL-2528 is stable with X7R, X5R, Z5U, and Y5V ceramic capacitors in the 1–22 µF range, provided ESR stays between 5 mΩ and 500 mΩ. However, Y5V capacitors can lose >50% capacitance from 25°C to 85°C, risking instability at high temperature. National Semiconductor recommends X7R for applications with wide ambient swings, as it maintains ±15% capacitance across −55°C to +125°C-ensuring robust regulation for LP3986BL-2528 across full spec.