Texas Instruments LP3982IMMX-2.82/NOPB

Overview

LP3982IMMX-2.82/NOPB from Texas Instruments (formerly National Semiconductor) is a micropower, ultra low-dropout, low-noise CMOS linear regulator delivering 300mA output at fixed 2.82V with 120mV typical dropout at full load, 90µA typical quiescent current, and 37µV_RMS output noise (10Hz–100kHz). It targets battery-powered DSP core power and portable information appliances where extended runtime and clean supply are critical.

For engineers reviewing the LP3982IMMX-2.82/NOPB datasheet, LP3982IMMX-2.82/NOPB pinout, LP3982IMMX-2.82/NOPB application, or LP3982IMMX-2.82/NOPB equivalent, key selection factors include its PMOS pass transistor architecture enabling 1nA shutdown current, stability with 2.2µF ceramic output capacitors, ±2% output voltage tolerance, and fault detection via open-drain FAULT pin.

Technical Context

The LP3982IMMX-2.82/NOPB employs a PMOS pass transistor topology with internal 1.25V bandgap reference and error amplifier for closed-loop regulation. Its feedback network is fully internal for fixed-output versions, eliminating external resistor dependencies and ensuring ±2% output accuracy across −40°C to +85°C.

Stability is achieved via an internally generated compensation zero that counteracts phase shift from low-ESR ceramic capacitors down to 2.2µF. The device integrates fault detection (monitoring input-to-output differential, overcurrent, and thermal overload), shutdown control (logic-level compatible SHDN pin), and fast 120µs turn-on time with optional 33nF noise bypass capacitor on the reference node.

Key Specifications

Pinout & Package

LP3982IMMX-2.82/NOPB is housed in an 8-pin MSOP package (NSC drawing MUA08A), 3.0mm × 3.0mm × 1.0mm profile, with exposed thermal pad for enhanced power dissipation (θ_JA = 223°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3982IMMX-2.82/NOPB, the MAX8860EUB28+T offers drop-in replacement capability but sacrifices fault visibility and noise performance, while the TLS850F2TE/V33 provides robustness for harsh environments at the cost of unnecessary input voltage range and missing low-noise features essential for portable electronics.

Availability

LP3982IMMX-2.82/NOPB is available at Aetrix Electronics and suitable for wireless handsets, DSP core power, and portable information appliances requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LP3982IMMX-2.82/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 acquired National Semiconductor in 2011 and maintains its precision analog and power management portfolio. TI is a global leader in semiconductor design and manufacturing, serving industrial, automotive, and consumer markets.

The LP3982IMMX-2.82/NOPB belongs to TI's legacy micropower LDO family, engineered specifically for battery-powered portable electronics demanding ultra-low quiescent current, low-noise regulation, and minimal dropout voltage.

FAQ

What is the maximum input voltage rating for LP3982IMMX-2.82/NOPB?

The absolute maximum input voltage for LP3982IMMX-2.82/NOPB is 6.5V, but the recommended operating range is 2.5V to 6.0V per the datasheet. Exceeding 6.0V risks violating safe operating area limits, especially under high ambient temperatures or heavy load conditions. Always maintain VIN ≤ 6.0V in normal operation to ensure reliability and longevity of the LP3982IMMX-2.82/NOPB.

Does LP3982IMMX-2.82/NOPB require an external capacitor on the CC pin?

Yes - LP3982IMMX-2.82/NOPB achieves its specified 37µV_RMS output noise only when a 33nF NPO or COG ceramic capacitor is connected between the CC pin (Pin 6) and ground. This capacitor directly bypasses the internal bandgap reference; omitting it increases RMS noise to ~100µV. The LP3982IMMX-2.82/NOPB remains functional without it, but noise-sensitive applications like audio or RF biasing will degrade performance.

Can LP3982IMMX-2.82/NOPB operate stably with a 1µF output capacitor?

No - LP3982IMMX-2.82/NOPB is characterized and guaranteed stable only with ≥2.2µF ceramic output capacitance. Using 1µF violates the minimum stability condition and may cause oscillation or poor transient response. The internal compensation zero is tuned for 2.2µF–10µF ceramic capacitors (X5R/X7R dielectrics); lower values risk phase margin erosion and instability in the LP3982IMMX-2.82/NOPB.

What is the purpose of the dual GND pins on LP3982IMMX-2.82/NOPB?

The dual GND pins (Pins 2 and 7) on LP3982IMMX-2.82/NOPB reduce ground path impedance and separate high-frequency return currents from the main power ground. This improves PSRR by >10dB at 1MHz and lowers output voltage ripple caused by load transients. Both pins must be connected to the same low-impedance ground plane; splitting them degrades noise performance and thermal dissipation in the LP3982IMMX-2.82/NOPB.

How does the FAULT pin on LP3982IMMX-2.82/NOPB behave during thermal shutdown?

During thermal shutdown, the FAULT pin on LP3982IMMX-2.82/NOPB goes low (open-drain active) and remains asserted until the junction temperature drops by ~10°C (hysteresis). It also activates for current-limit events and when the input-to-output differential falls below ~150mV - tracking the actual dropout threshold. A 100kΩ pull-up resistor is required to interface with microcontroller GPIOs for fault logging in LP3982IMMX-2.82/NOPB systems.