Texas Instruments TPS3850H18DRCT

Overview

TPS3850H18DRCT from Texas Instruments is a precision voltage supervisor IC with integrated programmable window watchdog timer, designed for high-reliability microcontroller and SoC power-rail monitoring. It delivers 0.8% threshold accuracy over –40°C to +125°C, supports 1.6 V–6.5 V supply range, features open-drain RESET and WDO outputs, and monitors rails from 0.9 V to 5.0 V - used in ultrasound scanners and active antenna systems.

For engineers reviewing the TPS3850H18DRCT datasheet, TPS3850H18DRCT pinout, TPS3850H18DRCT application, or TPS3850H18DRCT equivalent, this page provides verified specifications, validated pin functions, confirmed thermal and timing behavior, factory- and capacitor-programmable reset/watchdog delays, and real-world use cases in medical, telecom, and industrial embedded systems.

Technical Context

The TPS3850H18DRCT implements dual-threshold precision window supervision on the SENSE pin with ±0.8% accuracy across temperature, plus 0.5% hysteresis to prevent chatter near thresholds. Its state-machine-controlled window watchdog uses dedicated WDI input and WDO output to detect both early and late faults within user-configurable time boundaries.

Reset delay (tRST) and watchdog window boundaries (tWDL/tWDU) are set either by factory programming (e.g., 170–230 ms tRST with CRST = NC) or external capacitors (0.1–1000 nF), while SET0/SET1 logic pins select watchdog ratios (1/8, 3/4, 1/2) or disable the watchdog entirely - enabling flexible fault-detection tuning without firmware changes.

Key Specifications

Pinout & Package

TPS3850H18DRCT is housed in a thermally enhanced 3-mm × 3-mm, 10-pin VSON package (DRC) with exposed thermal pad internally connected to GND. The package supports reflow soldering and provides low 26.1°C/W junction-to-board thermal resistance for sustained operation at +125°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervision and watchdog timer applications.

Compared with TPS3850H18DRCT, TPS3851H18DRCT adds an LDO but increases power and pin count, while MAX6373KA29+T sacrifices window supervision, accuracy, and programmability for lower cost and legacy footprint - making TPS3850H18DRCT the optimal balance of precision, flexibility, and integration for modern embedded safety systems.

Availability

TPS3850H18DRCT is available at Aetrix Electronics and suitable for ultrasound scanner, active antenna system mMIMO, and infusion pump applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS3850H18DRCT 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 and embedded processing technologies, with decades of expertise in precision power management and reliability-critical IC design.

The TPS3850 family was developed to address growing demand for high-accuracy, multi-function supervisory ICs in medical imaging, 5G infrastructure, and industrial automation - combining window voltage monitoring and programmable watchdog in a single compact package.

FAQ

What is the exact overvoltage and undervoltage threshold for TPS3850H18DRCT?

The TPS3850H18DRCT is factory-configured for 1.8 V nominal SENSE rail supervision. Its overvoltage threshold (VIT+(OV)) is 1.8 V × 1.04 = 1.872 V, and undervoltage threshold (VIT−(UV)) is 1.8 V × 0.96 = 1.728 V - both with ±0.8% accuracy over −40°C to +125°C. These values are fixed per the 'H18' suffix and verified in TI's SBVS301B datasheet Section 6.5.

Can TPS3850H18DRCT monitor a 1.2-V rail?

No - the 'H18' in TPS3850H18DRCT denotes a factory-set 1.8-V threshold configuration. To supervise a 1.2-V rail, use TPS3850H12DRCT (1.2-V version) or TPS3850Gxx variants with adjustable thresholds. Attempting to use TPS3850H18DRCT on 1.2 V will cause immediate RESET assertion since 1.2 V falls below its 1.728 V undervoltage threshold.

How does the watchdog disable feature work on TPS3850H18DRCT?

The TPS3850H18DRCT watchdog is disabled when SET0 = HIGH and SET1 = LOW (per Table 6-6). In this state, WDI input is ignored, WDO remains high-impedance, and only voltage supervision remains active. This mode is intended for development or safe-boot sequences - but WDI must still be driven to VDD or GND (not left floating) when disabled.

What is the minimum capacitor value for programmable reset delay on TPS3850H18DRCT?

The minimum recommended capacitor for CRST is 0.1 nF, yielding a reset delay (tRST) of 703 µs (per Section 6.3). Using smaller values risks timing inaccuracy due to parasitic capacitance and internal evaluation window (tINIT = 381 µs). Capacitors below 0.1 nF are not characterized and may result in undefined tRST behavior.

Does TPS3850H18DRCT require external pull-up resistors on RESET and WDO?

Yes - both RESET and WDO are open-drain outputs and require external pull-up resistors (1 kΩ to 100 kΩ) to the appropriate logic rail (e.g., 3.3 V or 5 V). The resistor value affects VOL (output low voltage) and rise time; TI recommends 10 kΩ for general use. Leaving either output un-pulled will result in undefined logic levels and system malfunction.