Texas Instruments TPS3851G18EDRBT

Overview

TPS3851G18EDRBT from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for reliable power-up sequencing and fault detection in microcontroller-based systems. It monitors VDD (1.6V–6.5V), provides 0.8% undervoltage threshold accuracy at 1.728V (1.8V nominal), delivers 200ms reset timeout with 15% accuracy, and supports user-programmable or factory-set watchdog timeouts up to 1.84s - deployed in IP network cameras and string inverters requiring robust brownout protection.

For engineers reviewing the TPS3851G18EDRBT datasheet, TPS3851G18EDRBT pinout, TPS3851G18EDRBT application, or TPS3851G18EDRBT equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed thermal performance (–40°C to +125°C), exact VSON-8 package mapping, and real-world implementation constraints including open-drain RESET/WDO drive capability and CWD capacitor timing dependencies.

Technical Context

The TPS3851G18EDRBT implements a high-accuracy comparator-based undervoltage detection circuit with 0.5% hysteresis and a dedicated state machine for independent watchdog timing control. Its dual-path architecture separates reset assertion logic (triggered by VDD falling below VITN = 1.728V) from watchdog fault signaling (via WDO output), enabling selective system recovery without full reset.

Watchdog configuration is determined at power-on via CWD pin evaluation (381µs initialization), supporting three modes: capacitor-programmed (0.1–1000nF), 10kΩ pullup-enabled factory timing (170–1840ms), or SET1-grounded disable. All timing paths maintain 15% accuracy over temperature, and WDO only asserts when RESET is deasserted - ensuring fault isolation.

Key Specifications

Pinout & Package

TPS3851G18EDRBT is housed in a 3.00mm × 3.00mm, 8-pin VSON package (DRB) with exposed thermal pad connected internally to GND. The package supports automated optical inspection and offers low thermal resistance (RθJB = 25.8°C/W) for sustained operation in compact, thermally constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor with watchdog timer applications.

Compared with TPS3851G18EDRBT, TPS3851G33EDRBT offers identical functionality at a different threshold voltage, while MAX6373KA29+T sacrifices watchdog flexibility and precision for lower cost and simpler integration - making it unsuitable for firmware health monitoring in connected devices.

Availability

TPS3851G18EDRBT is available at Aetrix Electronics and suitable for IP network cameras, string inverters, blood pressure monitors, and electricity meters requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for TPS3851G18EDRBT 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 power management and system supervision ICs.

The TPS3851 product line delivers high-accuracy, multi-function supervisors for mission-critical applications in industrial automation, renewable energy, and medical electronics - emphasizing precision timing, wide temperature operation, and fault-isolation capability.

FAQ

What is the exact undervoltage threshold voltage of the TPS3851G18EDRBT?

The TPS3851G18EDRBT has a nominal undervoltage threshold (VITN) of 1.728V, corresponding to a 1.8V supply rail. This value is guaranteed within ±0.8% across –40°C to +125°C, as confirmed in the device's electrical characteristics table and Figure 5-7 of the SBVS300B datasheet. The 1.728V threshold ensures reliable detection before the 1.8V rail falls below its minimum specification for connected microcontrollers.

Does the TPS3851G18EDRBT support both 1.8V and 3.3V supply rails simultaneously?

No - the TPS3851G18EDRBT monitors a single supply rail (VDD) and is factory-trimmed for 1.8V nominal operation (VITN = 1.728V). It does not support dual-rail monitoring. For 3.3V supervision, TI offers the pin-compatible TPS3851G33EDRBT variant with VITN = 3.264V. Each device must be selected based on the specific rail voltage being supervised.

How is the watchdog timeout configured on the TPS3851G18EDRBT?

The TPS3851G18EDRBT watchdog timeout is configured at power-on via the CWD pin: leaving CWD unconnected or pulling it to VDD with a 10kΩ resistor selects factory-programmed timing (1600ms typical), while connecting a capacitor (0.1–1000nF) to GND enables user-programmable timing per Equation 1. The SET1 pin must be high to enable watchdog operation; grounding SET1 disables it entirely.

Can the TPS3851G18EDRBT's RESET and WDO outputs drive standard logic inputs directly?

No - both RESET and WDO are open-drain outputs and require external pullup resistors (1kΩ to 100kΩ) to a valid logic rail (1.8V–6.5V). They cannot source current or drive CMOS/TTL inputs without pullups. The pullup voltage must match the target logic family's VIH/VIL levels, and resistor value must be chosen considering VOL (≤0.4V @ 3mA) and capacitive loading to meet timing requirements.

What is the maximum junction temperature rating for continuous operation of the TPS3851G18EDRBT?

The TPS3851G18EDRBT is rated for continuous operation up to +125°C junction temperature, as specified in Section 5.3 Recommended Operating Conditions. Its VSON-8 package achieves RθJB = 25.8°C/W, allowing reliable thermal performance in sealed enclosures - validated in applications including string inverters and outdoor IP cameras where ambient temperatures exceed 85°C.