Texas Instruments TLV717185PDQNR

Overview

TLV717185PDQNR from Texas Instruments is a 150-mA, low-dropout linear regulator with fixed 1.85 V output, 215 mV dropout at full load, 0.5% typical output accuracy, and active pulldown for fast output discharge. It delivers stable regulation in space-constrained portable electronics requiring ultra-low quiescent current (35 µA) and high PSRR (70 dB at 1 kHz).

For engineers reviewing the TLV717185PDQNR datasheet, TLV717185PDQNR pinout, TLV717185PDQNR application, or TLV717185PDQNR equivalent, key selection criteria include foldback current limit (40 mA short-circuit), UVLO threshold (1.6 V), stability with 0.1 µF ceramic output capacitance, and operation across –40°C to +85°C junction temperature.

Technical Context

The TLV717185PDQNR uses a PMOS pass transistor architecture enabling very low dropout and inherent reverse-voltage protection via its body diode. Its foldback current limit reduces power dissipation during overload by throttling output current as VOUT drops - initiating near 350 mA and limiting short-circuit current to 40 mA.

It integrates an active pulldown resistor (120 Ω) to rapidly discharge the output when disabled, and features undervoltage lockout (UVLO) that holds regulation off until VIN exceeds 1.6 V. The enable pin operates with low-threshold logic compatibility (EN > 0.9 V to enable, < 0.4 V to disable), supporting direct connection to modern low-voltage GPIOs.

Key Specifications

Pinout & Package

TLV717185PDQNR is housed in a 1.0 mm × 1.0 mm, 4-pin X2SON (DQN) package with wettable flank terminations for automated optical inspection. Thermal pad on bottom must be connected to GND for optimal thermal performance (R_θJB = 330°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV717185PDQNR, TLV71718PDQNR offers identical form-factor and performance at 1.8 V, while TPS7A05185PDBVR trades foldback protection and compact packaging for extreme low-IQ operation - making TLV717185PDQNR optimal for space-constrained, fault-resilient 1.85 V applications.

Availability

TLV717185PDQNR is available at Aetrix Electronics and suitable for wearable health monitors, Bluetooth Low Energy modules, and industrial wireless sensors requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for TLV717185PDQNR 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 specializing in analog and embedded processing technologies, with leadership in power management ICs and precision analog solutions.

The TLV717P series was designed specifically for portable, battery-powered applications demanding low quiescent current, small footprint, and robust transient performance - targeting smartphones, wearables, and IoT edge nodes.

FAQ

What is the minimum input voltage required for TLV717185PDQNR to regulate at full 150 mA load?

The TLV717185PDQNR requires VIN ≥ VOUT + VDO = 1.85 V + 0.215 V = 2.065 V to maintain regulation at 150 mA. Below this, it enters dropout mode where VOUT tracks VIN minus dropout voltage. The device also requires VIN ≥ 1.6 V to exit UVLO and begin regulation - so functional startup occurs at 1.6 V, but full-load regulation starts at 2.065 V. This makes TLV717185PDQNR well-suited for single-cell Li-ion (2.7–4.2 V) and LiFePO₄ (2.0–3.6 V) systems.

Does TLV717185PDQNR require an input capacitor, and if so, what value is recommended?

While the TLV717185PDQNR is stable without an input capacitor, Texas Instruments recommends a 0.1 µF to 1 µF low-ESR ceramic capacitor between IN and GND. This improves transient response, reduces noise coupling from upstream sources, and mitigates voltage spikes caused by source inductance during load steps. For applications with high source impedance (>2 Ω) or fast load transients, a 1 µF capacitor is preferred. The capacitor should be placed as close as possible to the IN and GND pins to minimize loop inductance.

How does the foldback current limit function in TLV717185PDQNR during a short-circuit event?

In TLV717185PDQNR, foldback current limit reduces output current as VOUT falls - initiating near 350 mA and decreasing progressively until short-circuit current stabilizes at ~40 mA. Unlike fixed current limits, this behavior lowers power dissipation [(VIN – VOUT) × ILIMIT] in fault conditions, preventing thermal runaway. During a hard short, VOUT collapses to near 0 V and the device supplies only 40 mA, allowing safe operation without external current-limiting components or thermal shutdown intervention.

Can TLV717185PDQNR be used with non-ceramic output capacitors such as tantalum or aluminum electrolytic?

TLV717185PDQNR is optimized for ceramic capacitors and is guaranteed stable with ≥0.1 µF effective capacitance and ESR < 200 mΩ. While tantalum or aluminum electrolytic capacitors may work in some cases, their higher ESR and temperature/voltage derating can degrade PSRR, increase output noise, and cause instability - especially at low temperatures or high bias voltages. TI explicitly recommends X5R/X7R ceramics; using alternatives requires full system-level validation and is not advised for production designs relying on datasheet guarantees.

What is the purpose and value of the active pulldown resistor in TLV717185PDQNR?

The active pulldown resistor in TLV717185PDQNR is a 120 Ω internal path from OUT to GND that engages automatically when the device is disabled (EN < 0.4 V). It rapidly discharges output capacitance - clearing 1 µF in under 10 µs - ensuring clean power-down sequencing, preventing floating voltages on downstream logic, and meeting safety requirements in medical and industrial equipment. This eliminates the need for external bleed resistors, saving board space and BOM cost while improving reliability.