Texas Instruments TPS3851G18SDRBT

Overview

TPS3851G18SDRBT from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for microcontroller and SoC power-rail monitoring in industrial and embedded systems. It provides 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), open-drain RESET and WDO outputs, and supports 1.8 V supply rails with 0.5% hysteresis. It is used in Wi-Fi access points and IP cameras to ensure reliable system boot and fault recovery.

For engineers reviewing the TPS3851G18SDRBT datasheet, TPS3851G18SDRBT pinout, TPS3851G18SDRBT application, or TPS3851G18SDRBT equivalent, key selection criteria include its factory-programmed 1.728 V undervoltage threshold, user-selectable watchdog timing via CWD pin, manual reset input (MR), thermal robustness up to +125°C junction temperature, and compatibility with tight-tolerance 1.8 V rail supervision.

Technical Context

The TPS3851G18SDRBT implements a high-accuracy comparator-based undervoltage detection circuit with built-in 0.5% hysteresis, enabling stable operation in noisy environments without external components. Its reset delay uses an internal precision timing circuit achieving ±15% accuracy over temperature, independent of external RC networks.

Watchdog functionality operates via dual configuration modes: factory-programmed timeouts (1600 ms typical, selectable via SET1/CWD logic states) or user-adjustable timing using an external capacitor on CWD (0.1–1000 nF). The WDO output remains high-impedance when RESET is asserted, allowing independent fault signaling without triggering full system reset.

Key Specifications

Pinout & Package

TPS3851G18SDRBT is housed in a 3.00 mm × 3.00 mm, 8-pin VSON package (DRB) with exposed thermal pad connected internally to GND. The package supports automated optical inspection and offers low thermal resistance (R_θJB = 25.8°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G18QDBVRQ1, the TPS3851G18SDRBT offers broader industrial temperature range (+125°C vs +105°C) but lacks AEC-Q100 certification; compared with MAX6373KA29+T, it delivers precise 1.728 V threshold, programmable watchdog, and lower quiescent current-critical for 1.8 V embedded systems.

Availability

TPS3851G18SDRBT is available at Aetrix Electronics and suitable for WLAN access points, IP network cameras, and string inverter control boards requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TPS3851G18SDRBT 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, signal chain, and real-time control solutions.

The TPS3851 product line delivers high-accuracy voltage supervisors with integrated watchdog timers for mission-critical embedded systems where reliable power sequencing and fault detection are essential.

FAQ

What is the exact undervoltage threshold voltage of the TPS3851G18SDRBT?

The TPS3851G18SDRBT has a factory-trimmed undervoltage threshold (V_ITN) of 1.728 V, with ±0.8% accuracy over –40°C to +125°C. This value is optimized for 1.8 V supply rails, providing a 4% margin below nominal voltage. The threshold is laser-trimmed during production and verified per TI's SBVS300B datasheet revision June 2025.

How does the watchdog timeout get configured on the TPS3851G18SDRBT?

The TPS3851G18SDRBT supports three watchdog configuration methods: (1) leave CWD unconnected for factory-programmed 1600 ms timeout, (2) connect CWD to VDD via 10 kΩ resistor for 200 ms timeout, or (3) connect external capacitor (0.1–1000 nF) to GND for user-adjustable timing. SET1 must be high for watchdog activation; grounding SET1 disables it entirely.

Can the TPS3851G18SDRBT supervise voltages other than 1.8 V?

Yes - the TPS3851G18SDRBT operates from 1.6 V to 6.5 V and supports supervision of 1.8 V, 2.5 V, 3.0 V, 3.3 V, and 5.0 V rails. While its V_ITN is fixed at 1.728 V, it can monitor any rail within that range by connecting VDD to the target supply. For higher thresholds, TI offers variants like TPS3851G25 (2.45 V) and TPS3851G33 (3.2 V).

What is the function of the WDO pin on the TPS3851G18SDRBT?

The WDO (Watchdog Output) pin on the TPS3851G18SDRBT is an open-drain fault indicator that asserts low only when a watchdog timeout occurs *and* RESET is high. It remains high-impedance when RESET is low, enabling independent fault signaling without forcing a system reset. This allows diagnostics, logging, or selective subsystem recovery while maintaining overall system stability.

Does the TPS3851G18SDRBT require external components for basic operation?

For basic operation, the TPS3851G18SDRBT requires only two external components: a 0.1 µF ceramic bypass capacitor on VDD and pullup resistors (1–100 kΩ) on RESET and WDO. No external timing resistors or capacitors are needed when using factory-programmed watchdog modes. The MR pin may be left floating (internally pulled up) if manual reset is unused.