Texas Instruments TPS3851H50EDRBR

Overview

TPS3851H50EDRBR from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for system-level power integrity monitoring in microcontroller-based embedded systems. It delivers 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), and user-programmable or factory-set watchdog timeouts up to 1.84 s - enabling reliable startup sequencing and fault recovery in industrial IoT edge nodes.

For engineers reviewing the TPS3851H50EDRBR datasheet, TPS3851H50EDRBR pinout, TPS3851H50EDRBR application, or TPS3851H50EDRBR equivalent, this device supports tight-tolerance rail supervision (1.8V–5.0V), offers open-drain RESET/WDO outputs with 0.5% hysteresis, and integrates manual reset (MR), watchdog disable (SET1), and capacitor-programmable timing (CWD) - critical for Wi-Fi access points, IP cameras, and smart metering designs requiring high-accuracy power-on-reset and runtime fault detection.

Technical Context

The TPS3851H50EDRBR implements a precision bandgap-referenced comparator for undervoltage detection and a state-machine-controlled watchdog timer with dual timing modes (standard/extended). Its VITN = 4.8 V (H50 variant) is factory-trimmed with 0.8% accuracy across temperature, and hysteresis is fixed at 0.5% of VITN - eliminating external components for stable threshold behavior in noisy environments.

Watchdog operation is configurable via CWD (capacitor or 10 kΩ pullup) and SET1 (enable/disable), with tWD ranging from 170 ms (factory-standard) to 1.84 s (factory-extended); WDO asserts independently of RESET, allowing fault isolation without full system reset. MR input provides synchronous manual reset with internal 620 nA pullup and sub-µs propagation delay.

Key Specifications

Pinout & Package

TPS3851H50EDRBR is housed in a thermally enhanced 3.00 mm × 3.00 mm, 8-pin VSON (DRB) package with exposed thermal pad connected internally to GND - enabling efficient heat dissipation in compact, high-density 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 TPS3851H50EDRBR, the G50 variant trades 20°C junction range for lower cost in non-extended-temperature applications, while the MAX6369KA29+T omits programmable watchdog and independent WDO - making it suitable only for basic reset-only supervision without runtime fault isolation capability.

Availability

TPS3851H50EDRBR is available at Aetrix Electronics and suitable for WLAN access points, IP network cameras, string inverters, and portable medical devices requiring stable component supply with guaranteed long-term manufacturability and automotive-grade thermal reliability.

Supply support for TPS3851H50EDRBR 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 power management technologies, with decades of expertise in high-reliability supervisory circuits for mission-critical systems.

The TPS3851 product line is engineered for precision power integrity in microcontroller-based systems - delivering ultra-accurate voltage monitoring, flexible watchdog timing, and robust operation across extended industrial and automotive temperature ranges.

FAQ

What is the exact undervoltage threshold voltage for TPS3851H50EDRBR?

The TPS3851H50EDRBR has a factory-trimmed undervoltage threshold (VITN) of 4.8 V with ±0.8% accuracy over –40°C to +125°C. This value is confirmed in the device's orderable part number suffix "H50", where "H" denotes the high-temperature grade and "50" specifies the 4.8 V nominal threshold. The 0.5% hysteresis adds 24 mV, resulting in a clean 4.824 V turn-on point after undervoltage recovery.

How does the watchdog timeout get configured on TPS3851H50EDRBR?

The TPS3851H50EDRBR supports three watchdog timeout configurations: (1) leave CWD unconnected for 1600 ms typical factory-standard timing, (2) connect CWD to VDD via 10 kΩ resistor for 200 ms typical factory-standard timing, or (3) connect a capacitor between CWD and GND to achieve user-defined timeouts from 0.7 ms to 77 s. SET1 must be high for any watchdog operation; grounding SET1 disables the watchdog entirely.

Can TPS3851H50EDRBR monitor multiple supply rails simultaneously?

No, the TPS3851H50EDRBR monitors only the VDD supply rail - the same pin that powers the IC. It does not support multi-rail supervision. For systems requiring independent monitoring of 1.8 V, 3.3 V, and 5 V rails, multiple TPS3851H50EDRBR units or a multi-channel supervisor like the TPS386000 would be required. Its design focuses on high-accuracy single-rail supervision with integrated watchdog functionality.

What is the function of the WDO pin on TPS3851H50EDRBR, and how does it differ from RESET?

The WDO (Watchdog Output) pin on TPS3851H50EDRBR asserts low independently of RESET when a watchdog timeout occurs - but only when RESET is high. If RESET is low (e.g., during undervoltage), WDO enters high-impedance state. This decoupling allows fault diagnostics without triggering full system reset, enabling graceful recovery or error logging in applications like IP cameras and smart meters where uninterrupted operation is critical.

Is the thermal pad on the TPS3851H50EDRBR package required to be connected to ground?

Yes, the exposed thermal pad on the TPS3851H50EDRBR's VSON-8 (DRB) package is internally connected to GND and must be soldered to a large-area PCB ground plane. This connection is mandatory for both electrical functionality (providing low-impedance ground return) and thermal performance - achieving RθJB = 25.8°C/W. Omitting thermal pad connection risks exceeding junction temperature limits and violating absolute maximum ratings under sustained load.