Texas Instruments TPS73618QDCQRQ1

Overview

TPS73618QDCQRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified, fixed-output 1.8 V, 400-mA NMOS low-dropout regulator with ultra-low 75 mV typical dropout voltage, 30 μVRMS output noise (10 Hz–100 kHz), and capacitor-free stability. It operates from 1.7 V to 5.5 V input and delivers ±0.5% initial accuracy for powering noise-sensitive analog circuitry in vehicle infotainment and ADAS subsystems.

For engineers reviewing the TPS73618QDCQRQ1 datasheet, TPS73618QDCQRQ1 pinout, TPS73618QDCQRQ1 application, or TPS73618QDCQRQ1 equivalent, key selection criteria include its no-output-capacitor operation, thermal shutdown at +160°C, EN-active-high control interface, reverse leakage <10 μA, and SOT-223-6 DCQ package with exposed thermal pad.

Technical Context

The TPS73618QDCQRQ1 employs an NMOS pass transistor in voltage-follower topology, enabling stable regulation without mandatory output capacitance and delivering near-constant ground pin current (400–1000 μA) across 10–400 mA load range. Its internal charge pump generates gate drive above VOUT, supporting ultra-low dropout while maintaining high reverse blockage.

This architecture yields 0.002%/mA load regulation and 0.01%/V line regulation, with PSRR of 58 dB at 100 Hz and 37 dB at 10 kHz under 400 mA load. The NR pin accepts an external capacitor to reduce reference noise-32 μVRMS at NR becomes 8.5 × VOUT μVRMS at OUT when CNR = 0.01 μF.

Key Specifications

Pinout & Package

SOT-223-6 (DCQ) package with exposed thermal pad connected to GND; optimized for automotive thermal cycling and board-level reliability. Thermal resistance θJA = 70.4°C/W on JEDEC high-K board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79618QDCQRQ1 and TLV73318PQDBVRQ1, the TPS73618QDCQRQ1 uniquely combines 400 mA capability, capacitor-free stability, and 30 μVRMS noise-making it the only AEC-Q100 Grade 1 option meeting all three requirements simultaneously in SOT-223.

Availability

TPS73618QDCQRQ1 is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, and radar signal chain power rails requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for TPS73618QDCQRQ1 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 specializing in analog, embedded processing, and automotive-grade power management solutions, with decades of automotive qualification expertise.

The TPS736xx-Q1 product line was designed specifically for AEC-Q100 Grade 1 automotive applications demanding ultra-low noise, capacitor-free operation, and robust thermal/ESD performance in engine bay and cabin environments.

FAQ

What is the minimum input voltage required for TPS73618QDCQRQ1 to deliver full 400 mA at 1.8 V output?

The TPS73618QDCQRQ1 requires VIN ≥ VOUT + VDO = 1.8 V + 0.075 V = 1.875 V to sustain 400 mA output. Below this, dropout occurs and regulation degrades. At 1.7 V input, maximum output current drops to ~100 mA per Figure 4 in the datasheet. Always maintain ≥100 mV headroom for reliable full-load operation.

Does TPS73618QDCQRQ1 require an output capacitor for stability, and what happens if none is used?

No, the TPS73618QDCQRQ1 is explicitly designed for capacitor-free stability-its NMOS voltage-follower topology achieves >60° phase margin with zero output capacitance. Without COUT, load transient undershoot increases slightly but recovers within 200 μs; adding 1 μF reduces undershoot magnitude but extends recovery time. Stability is guaranteed across all capacitor types and values.

How does the NR pin function in TPS73618QDCQRQ1, and what capacitor value is recommended?

The NR pin connects to the internal bandgap reference. Adding a capacitor (CNR) from NR to GND forms a low-pass filter that attenuates reference noise. For TPS73618QDCQRQ1, TI recommends 0.01 μF to achieve 8.5 × VOUT = 15.3 μVRMS output noise (10 Hz–100 kHz). Larger CNR further reduces noise but adds board area; 0.001–0.1 μF is the validated range.

What thermal derating applies to TPS73618QDCQRQ1 in SOT-223-6 (DCQ) package at +105°C ambient?

In SOT-223-6 (DCQ), θJA = 70.4°C/W. At TA = +105°C, maximum allowable junction temperature TJ(max) = +125°C, so ΔT = 20°C. Max power dissipation = 20°C / 70.4°C/W ≈ 284 mW. With 1.8 V output and 400 mA load, PD = (VIN − 1.8 V) × 0.4 A. To stay within limit, VIN must be ≤ 2.51 V at +105°C ambient-requiring careful input voltage selection or heatsinking.

Is TPS73618QDCQRQ1 pin-compatible with other members of the TPS736xx-Q1 family, such as TPS73625QDCQRQ1?

Yes, all TPS736xx-Q1 variants in SOT-223-6 (DCQ) package-including TPS73618QDCQRQ1, TPS73625QDCQRQ1, and TPS73633QDCQRQ1-share identical pinout, package dimensions, thermal pad layout, and electrical interface. Only the fixed output voltage differs; no PCB redesign is needed when substituting between these variants for voltage-scaling design iterations.