Texas Instruments TPS7A4518DCQT

Overview

TPS7A4518DCQT from Texas Instruments is a fixed-output 1.8 V, 1.5-A low-dropout (LDO) voltage regulator optimized for fast transient response and low-noise RF supply applications. It delivers 1.5 A output current with 300 mV dropout at full load, 1% output voltage accuracy at 25°C, and 35 μVRMS output noise (10 Hz–100 kHz). It operates with only a 10-μF ceramic output capacitor and includes reverse-battery and reverse-current protection.

For engineers reviewing the TPS7A4518DCQT datasheet, TPS7A4518DCQT pinout, TPS7A4518DCQT application, or TPS7A4518DCQT equivalent, key selection criteria include its 1.8 V fixed output, SOT-223-6 package thermal performance (RθJA = 50.5°C/W), shutdown quiescent current <1 μA, and Kelvin-sense capability via SENSE pin for precision regulation in high-current PCB traces.

Technical Context

The TPS7A4518DCQT uses a PMOS pass element architecture enabling controlled quiescent current in dropout-unlike NMOS-based LDOs-and eliminates need for external protection diodes. Its error amplifier features a dedicated SENSE pin that enables remote sensing to compensate for IR drop across PCB traces up to 600 μA bias current.

It integrates reverse-battery protection (withstands –20 V on IN), reverse-current protection (blocks >600 μA reverse flow from OUT to GND), thermal shutdown, and current limiting (1.6 A typical). The device maintains stability with ≥10 μF ceramic output capacitance and achieves 68 dB ripple rejection at 1 kHz.

Key Specifications

Pinout & Package

SOT-223-6 (DCQ) package: 6.50 mm × 7.06 mm body, exposed thermal pad connected to GND; requires PCB copper pour for thermal management per RθJB = 5.1°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4518DCQT, TPS7A4701RGWR offers superior noise performance but sacrifices output current and fixed-voltage convenience, while MCP1826T-1802E/DB provides functional equivalence at lower cost but lacks SENSE-based accuracy and transient speed-making TPS7A4518DCQT optimal for RF and precision analog applications demanding both current and regulation fidelity.

Availability

TPS7A4518DCQT is available at Aetrix Electronics and suitable for wireless infrastructure, industrial PLCs, medical imaging sensors, and automotive ADAS camera modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS7A4518DCQT 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 and embedded processing solutions for industrial, automotive, and communications markets.

The TPS7A45xx product line was engineered specifically for high-performance, low-noise power delivery in RF and fast-transient digital systems-emphasizing regulation accuracy, thermal resilience, and integrated protection.

FAQ

What is the maximum input voltage rating for the TPS7A4518DCQT?

The TPS7A4518DCQT has an absolute maximum input voltage of 20 V on the IN pin. Exceeding this may cause permanent damage. For reliable operation, the recommended input range is 2.8 V to 20 V, with minimum VIN dependent on load current-e.g., 2.5 V required at 1.5 A to maintain 1.8 V output given its 300 mV dropout specification.

Does the TPS7A4518DCQT require an external capacitor on the SENSE pin?

No, the TPS7A4518DCQT does not require an external capacitor on the SENSE pin. The SENSE pin is a high-impedance feedback input (600 μA bias current) intended for direct connection to the OUT pin-or to the load for Kelvin sensing. Adding capacitance here would destabilize the control loop and is not supported per the datasheet.

Can the TPS7A4518DCQT be used with a 10-μF ceramic output capacitor only?

Yes, the TPS7A4518DCQT is explicitly characterized and guaranteed stable with a minimum 10-μF ceramic output capacitor (X5R/X7R dielectric). Unlike many LDOs, it does not require added ESR or tantalum capacitors-enabling smaller, more reliable, and lower-cost output filtering in space-constrained designs.

How does the SENSE pin improve regulation accuracy in the TPS7A4518DCQT?

The SENSE pin in the TPS7A4518DCQT enables Kelvin (4-wire) feedback by connecting directly to the load instead of the OUT pin. This cancels voltage drop across PCB traces between the regulator and load-ensuring the error amplifier regulates precisely at the point of use. For example, with 50 mΩ trace resistance and 1.5 A load, it corrects for up to 75 mV of IR loss.

What thermal derating applies to the TPS7A4518DCQT in SOT-223-6 package?

In the DCQ (SOT-223-6) package, the TPS7A4518DCQT has RθJA = 50.5°C/W. At 1.5 A and 300 mV dropout (0.45 W dissipation), junction temperature rise is ~22.8°C above ambient. With 125°C max TJ and 85°C max ambient, usable power dissipation is limited to ~0.79 W-requiring careful PCB copper area design or forced airflow for high-power, high-temperature deployments.