Texas Instruments LP3961EMP-5.0/NOPB

Overview

LP3961EMP-5.0/NOPB from Texas Instruments is a fixed-output 5.0 V, 800-mA ultra-low-dropout linear regulator in SOT-223 package, featuring 24 mV dropout at 80 mA and 240 mV at 800 mA, ±1.5% output voltage accuracy, and an ERROR flag for output undervoltage detection - used in microprocessor core power supplies where tight regulation and fast transient response are critical.

For engineers reviewing the LP3961EMP-5.0/NOPB datasheet, LP3961EMP-5.0/NOPB pinout, LP3961EMP-5.0/NOPB application, or LP3961EMP-5.0/NOPB equivalent, key selection considerations include dropout performance under 800-mA load, ERROR flag hysteresis (5–16%), shutdown quiescent current (15 µA), thermal shutdown threshold (165°C), and compatibility with low-ESR tantalum output capacitors (33 µF min, 0.2–5 Ω ESR).

Technical Context

The LP3961EMP-5.0/NOPB uses a PMOS pass element with 240 mΩ typical R_DS(on), enabling ultra-low dropout operation down to 24 mV at light load. Its ERROR flag comparator monitors output voltage with 10% nominal threshold and built-in hysteresis, asserting low when V_OUT falls below regulation - independent of input voltage or temperature drift.

It operates across −40°C to 125°C junction temperature, supports 2.5 V to 7 V input, and delivers stable 5.0 V output with 0.02% load regulation and 0.02% line regulation. Shutdown is controlled via CMOS-compatible SD pin, requiring external 10-kΩ pullup for valid logic-level operation.

Key Specifications

Pinout & Package

SOT-223 (5-pin) package: 6.50 mm × 3.56 mm body size, thermally enhanced with exposed pad (connected to GND); suitable for surface-mount assembly and moderate-power dissipation without external heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSS721AIPW and TPS76350QDBVRQ1, the LP3961EMP-5.0/NOPB uniquely combines 800 mA output, 240 mV dropout, and integrated ERROR flag in SOT-223 - making it irreplaceable in 5-V microprocessor core and high-current bus termination roles where both performance and fault visibility are required.

Availability

LP3961EMP-5.0/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL bus terminators, SCSI termination circuits, and post-regulation stages requiring stable component supply with guaranteed long-term sourcing.

Supply support for LP3961EMP-5.0/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 is a global semiconductor leader designing analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The LP396x series was developed as fast ultra-low-dropout linear regulators targeting low-voltage microprocessor and bus-termination applications demanding high accuracy, low noise, and robust fault reporting - with LP3961EMP-5.0/NOPB optimized for fixed 5.0 V, 800 mA use cases.

FAQ

What is the minimum input voltage required for LP3961EMP-5.0/NOPB to regulate 5.0 V at full 800 mA load?

The LP3961EMP-5.0/NOPB requires a minimum input voltage of 5.24 V to maintain regulation at 800 mA, based on its 240 mV typical dropout voltage. At lighter loads (e.g., 80 mA), the dropout drops to 24 mV, allowing operation from as low as 5.024 V. Input voltage must remain ≥2.5 V per absolute ratings, but functional regulation begins at V_OUT + V_DROPOUT.

How does the ERROR flag on LP3961EMP-5.0/NOPB behave during thermal shutdown?

During thermal shutdown, the LP3961EMP-5.0/NOPB's ERROR flag asserts low - consistent with its design to indicate any condition causing output undervoltage, including overtemperature, overcurrent, or insufficient input headroom. The flag remains low until V_OUT recovers to ≥90% of nominal (i.e., ≥4.5 V) and thermal conditions stabilize within hysteresis limits.

Can LP3961EMP-5.0/NOPB operate without an external pullup resistor on the ERROR pin?

No - the ERROR pin is open-drain and requires an external pullup resistor (typically 10 kΩ to VIN) to provide a defined high state when the flag is inactive. Without it, the pin floats and cannot reliably signal normal operation. If the ERROR function is unused, TI specifies connecting the pin directly to GND - not leaving it unconnected.

What output capacitor specifications are mandatory for stable operation of LP3961EMP-5.0/NOPB?

LP3961EMP-5.0/NOPB requires a minimum 33 µF output capacitor with ESR between 0.2 Ω and 5 Ω for loop stability. Ceramic capacitors alone are unsuitable due to excessively low ESR; solid tantalum is recommended. The capacitor must maintain both capacitance and ESR within spec across −40°C to 125°C - verified per manufacturer's datasheet.

Is LP3961EMP-5.0/NOPB pin-compatible with other devices in the LP396x family, such as LP3964 variants?

No - LP3961EMP-5.0/NOPB (SOT-223, 5-pin, ERROR pin) is not pin-compatible with LP3964 variants, which feature a SENSE/ADJ pin instead of ERROR and differ in pin assignment (e.g., SENSE on Pin 5 vs. GND on Pin 5 for LP3961). PCB layout must be specific to LP3961EMP-5.0/NOPB's pinout; no mechanical or electrical interchangeability exists.