Texas Instruments TPS79918QDDCRQ1

Overview

TPS79918QDDCRQ1 from Texas Instruments is an AEC-Q100 qualified automotive-grade 200-mA low-dropout linear regulator with fixed 1.8-V output, enable control, 40-μA quiescent current, 29.5-μV_RMS output noise, and 100-mV typical dropout at full load-designed for powering noise-sensitive analog and RF circuitry in infotainment and ADAS modules.

For engineers reviewing the TPS79918QDDCRQ1 datasheet, TPS79918QDDCRQ1 pinout, TPS79918QDDCRQ1 application, or TPS79918QDDCRQ1 equivalent, key selection criteria include ultra-low noise performance under 100-kHz bandwidth, high PSRR (66 dB @ 1 kHz), fast 45-μs start-up with NR-pin support, and operation across –40°C to +125°C junction temperature with ±2% total output accuracy.

Technical Context

The TPS79918QDDCRQ1 employs a PMOS pass transistor architecture enabling low dropout and high PSRR at minimal headroom. Its high-gain, high-bandwidth error amplifier delivers excellent line and load transient response while maintaining 40-μA ground current across 500 μA–200 mA load range.

A dedicated noise-reduction (NR) pin allows external 0.01-μF capacitor bypassing of the internal bandgap reference, reducing output noise to 29.5 μV_RMS. An integrated quick-start circuit charges the NR capacitor within 135 μs, enabling simultaneous ultra-low noise and fast 45-μs start-up-critical for automotive power sequencing.

Key Specifications

Pinout & Package

TPS79918QDDCRQ1 is packaged in a 5-pin SOT-23 (DDC) with 2.9 mm × 2.8 mm footprint and exposed thermal pad connected to GND. The package supports high-density automotive PCB layouts and provides adequate thermal dissipation (R_θJA = 178.1°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79918QDDCRQ1, the WSON-packaged TPS79918QWDRBRQ1 offers superior thermal management for high-power-density modules, while NCP1117ST18T3G trades automotive reliability and noise performance for higher current capacity and lower cost in non-automotive contexts.

Availability

TPS79918QDDCRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and radar sensor power supplies requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for TPS79918QDDCRQ1 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 electronics, with decades of experience in high-reliability power management solutions.

The TPS799-Q1 product line delivers ultra-low-noise, high-PSRR LDOs optimized for automotive signal-chain applications-including infotainment, ADAS sensors, and radar front-ends-where precision regulation and EMI resilience are critical.

FAQ

What is the maximum input voltage rating for TPS79918QDDCRQ1?

The absolute maximum input voltage for TPS79918QDDCRQ1 is 7 V. However, the recommended operating range is 2.7 V to 6.5 V. Operation above 6.5 V risks exceeding thermal limits and degrading long-term reliability-even if within absolute max ratings-so system design must maintain VIN ≤ 6.5 V under all conditions including transients.

Does TPS79918QDDCRQ1 require an external noise-reduction capacitor to achieve its specified 29.5-μVRMS noise?

Yes, TPS79918QDDCRQ1 achieves 29.5-μV_RMS output noise only when a 0.01-μF ceramic capacitor is connected between the NR pin and GND. Without this capacitor, output noise rises to approximately 94 × V_OUT μV_RMS (≈170 μV_RMS at 1.8 V). The NR capacitor must be low-leakage (e.g., X7R/X5R) and placed close to the NR pin.

Can TPS79918QDDCRQ1 operate without any load connected to its output?

TPS79918QDDCRQ1 remains stable with zero load, but output voltage accuracy is only guaranteed for loads ≥500 μA. At light loads near 125°C junction temperature, the output may drift upward by up to 5%, triggering the internal pulldown circuit. For production designs, maintain ≥500 μA minimum load or verify accuracy under worst-case thermal conditions.

What is the purpose of the NR pin on TPS79918QDDCRQ1, and how does it differ from the FB pin on adjustable variants?

The NR pin on TPS79918QDDCRQ1 bypasses noise from the internal bandgap reference, directly lowering output noise. It is exclusive to fixed-output versions. Adjustable variants like TPS79901-Q1 use an FB pin for voltage-setting feedback and lack NR functionality-making them unsuitable for ultra-low-noise applications requiring <30 μV_RMS performance.

How does the enable (EN) pin behavior affect power sequencing in automotive systems using TPS79918QDDCRQ1?

The EN pin of TPS79918QDDCRQ1 is active-high with TTL/CMOS-compatible thresholds (ON ≥1.2 V, OFF ≤0.4 V). When used for power sequencing, driving EN high after VIN stabilizes ensures controlled 45-μs start-up without inrush current spikes. If EN is tied to VIN, start-up occurs immediately with input power-requiring careful coordination with upstream supply ramp rates to avoid undershoot.