Texas Instruments LP38693QSDX-3.3/NOPB

Overview

LP38693QSDX-3.3/NOPB from Texas Instruments is a 500-mA, 3.3-V fixed-output CMOS low-dropout linear regulator in a 6-pin WSON package with exposed thermal pad. It features 250 mV typical dropout at 500 mA (V_OUT = 5 V), ±2% output accuracy over –40°C to 125°C, and stable operation with only 1-µF ceramic output capacitance. It is used in battery-powered portable instrumentation where compact size, low quiescent current, and remote sensing capability are critical.

For engineers reviewing the LP38693QSDX-3.3/NOPB datasheet, LP38693QSDX-3.3/NOPB pinout, LP38693QSDX-3.3/NOPB application, or LP38693QSDX-3.3/NOPB equivalent, key selection considerations include enable-controlled power sequencing, SNS pin support for remote voltage sensing, thermal shutdown behavior at 160°C, and compatibility with ultra-low-ESR ceramic capacitors without external compensation.

Technical Context

The LP38693QSDX-3.3/NOPB uses a PMOS pass transistor architecture enabling ground pin current under 100 µA across load, input voltage, and temperature - eliminating base-drive losses. Its internal trimmed bandgap reference and feedback loop deliver tight DC regulation and fast transient response, supported by foldback current limiting that scales with VIN–VOUT differential (e.g., ~350 mA limit at >5 V drop, ~850 mA at <4 V drop).

Unlike the LP38691, the LP38693QSDX-3.3/NOPB integrates an active-enable logic input (EN) referenced to GND, requiring ≥3 V at VIN = 6 V to fully turn on, and supports shutdown with ≤0.4 V input. The SNS pin - present only in WSON variants - enables Kelvin-sense connection directly at the load to cancel PCB trace IR drop, ensuring regulated voltage accuracy at point-of-load.

Key Specifications

Pinout & Package

The LP38693QSDX-3.3/NOPB is housed in a 3.0 mm × 3.0 mm, 6-pin WSON package with exposed thermal pad (DAP) on the bottom for enhanced heat dissipation. The DAP must be soldered to a PCB copper plane per TI AN-1187 for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LDR and TPS7A2033PDQNR, the LP38693QSDX-3.3/NOPB uniquely combines 500-mA capability, enable control, remote sensing, and ±2% accuracy in a thermally robust WSON package - making it irreplaceable for high-fidelity, sequenced, and point-of-load 3.3-V regulation in portable industrial systems.

Availability

LP38693QSDX-3.3/NOPB is available at Aetrix Electronics and suitable for battery-powered devices, portable instrumentation, and notebook computer subsystems requiring stable component supply, long-term lifecycle support, and guaranteed AEC-Q100-compliant variants.

Supply support for LP38693QSDX-3.3/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 company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and system-on-chip solutions for industrial, automotive, and consumer markets.

The LP38693QSDX-3.3/NOPB belongs to TI's LP3869x family of CMOS LDOs engineered for portable, battery-powered digital systems demanding fast start-up, low dropout, and ceramic-capacitor stability - especially where space, thermal performance, and enable-controlled sequencing are critical.

FAQ

What is the minimum input voltage required for LP38693QSDX-3.3/NOPB to regulate 3.3 V output?

The LP38693QSDX-3.3/NOPB requires VIN ≥ (V_OUT + V_DO) or 2.7 V, whichever is higher. With a typical dropout of 330 mV at 500 mA, the minimum functional VIN is 3.63 V. Below 2.7 V, internal circuitry is nonfunctional; regulation begins only once VIN exceeds both the dropout threshold and 2.7 V.

Does LP38693QSDX-3.3/NOPB require external compensation components?

No. The LP38693QSDX-3.3/NOPB is internally compensated and stable with only a 1-µF ceramic output capacitor - no ESR requirements or external RC networks needed. This eliminates tuning effort and improves reliability versus older LDOs requiring specific capacitor types or values.

How does the SNS pin on LP38693QSDX-3.3/NOPB improve regulation accuracy?

The SNS pin on LP38693QSDX-3.3/NOPB enables remote voltage sensing at the load, closing the feedback loop directly at the point-of-load. This cancels voltage drop across PCB traces and connectors, improving load regulation accuracy from ±2% (local sense) to ±0.5% typical - critical for precision analog or high-speed digital loads.

Can LP38693QSDX-3.3/NOPB be used in automotive applications?

Yes - the LP38693QSDX-3.3/NOPB is the commercial-grade version of the AEC-Q100 Grade 1 qualified LP38693-Q1. While LP38693QSDX-3.3/NOPB itself is not Q100-certified, its identical electrical and thermal specifications make it suitable for non-safety-critical automotive subsystems (e.g., infotainment peripherals) when validated per customer requirements.

What happens to LP38693QSDX-3.3/NOPB during thermal shutdown?

When the junction temperature reaches 160°C, LP38693QSDX-3.3/NOPB disables the output and enters thermal shutdown. It remains off until the junction cools to ~150°C (10°C hysteresis), then automatically resumes regulation. Continuous cycling indicates insufficient PCB copper or excessive power dissipation - redesign thermal layout before deployment.