Texas Instruments TPS3851H25EDRBT

Overview

TPS3851H25EDRBT from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for reliable power monitoring and fault detection in microcontroller-based systems. It delivers 0.8% undervoltage threshold accuracy over –40°C to +125°C, 200 ms reset timeout (±15%), 10 µA quiescent current, and supports 1.8 V to 5.0 V supply rails - enabling robust system startup and brownout protection in industrial IoT edge nodes.

For engineers reviewing the TPS3851H25EDRBT datasheet, TPS3851H25EDRBT pinout, TPS3851H25EDRBT application, or TPS3851H25EDRBT equivalent, this device serves as a high-accuracy supervisory solution where tight tolerance voltage monitoring, programmable watchdog timing, and open-drain reset/watchdog outputs are required for safety-critical embedded control and remote sensing applications.

Technical Context

The TPS3851H25EDRBT implements a precision comparator-based undervoltage detection circuit with 0.5% hysteresis and factory-programmed reset delay (tRST = 200 ms typ). Its watchdog function operates independently via dedicated WDI input and WDO output, supporting both user-adjustable capacitor timing and factory-set timeouts (1600 ms standard, 200 ms extended).

It uses dual configuration logic: SET1 pin disables the watchdog entirely, while CWD pin selects between capacitor-programmable mode (0.1–1000 nF) and factory-timed modes (via NC or 10 kΩ pullup). All timing paths are validated across –40°C to +125°C with ±15% accuracy for tRST and tWD.

Key Specifications

Pinout & Package

TPS3851H25EDRBT 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 high-density PCB layouts and efficient heat dissipation in thermally constrained enclosures.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G25EDRBT, the TPS3851H25EDRBT offers configurable undervoltage hysteresis (4% or 7%) rather than fixed threshold, enabling tighter margin control. Against MAX6371UT25+T, it delivers superior accuracy, independent fault signaling, and full industrial temperature support - critical for field-deployed equipment with zero-reset tolerance.

Availability

TPS3851H25EDRBT is available at Aetrix Electronics and suitable for WLAN access points, wireless security cameras, IP network cameras, and string inverters requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for industrial OEM programs.

Supply support for TPS3851H25EDRBT 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 high-reliability ICs.

The TPS3851 family is designed for precision power supervision in mission-critical embedded systems - targeting applications demanding guaranteed reset behavior, watchdog autonomy, and operation across extended industrial temperature ranges.

FAQ

What is the undervoltage threshold accuracy of the TPS3851H25EDRBT over temperature?

The TPS3851H25EDRBT achieves ±0.8% undervoltage threshold (VITN) accuracy across the full operating junction temperature range of –40°C to +125°C. This specification is validated per TI's production test flow and applies to both 4% and 7% UVLO configurations on the 2.5 V nominal rail. The accuracy includes hysteresis contribution and is confirmed using statistical process control on >36,000 units.

How does the TPS3851H25EDRBT implement watchdog timeout selection?

The TPS3851H25EDRBT selects watchdog timeout via the CWD and SET1 pins: leaving CWD unconnected or pulling it to VDD with 10 kΩ enables factory-programmed modes (1600 ms standard or 200 ms extended), while connecting a capacitor (0.1–1000 nF) to CWD enables user-adjustable timing. SET1 = GND disables the watchdog entirely. All configurations are evaluated at power-up within 381 µs.

Can the TPS3851H25EDRBT monitor multiple voltage rails simultaneously?

No - the TPS3851H25EDRBT monitors only the VDD supply rail. It does not include auxiliary sense inputs or multi-rail comparators. For systems requiring supervision of multiple rails (e.g., 1.8 V, 3.3 V, 5.0 V), separate TPS3851H25EDRBT devices or a multi-channel supervisor like TPS386000 must be used. Each TPS3851H25EDRBT instance supervises one rail with dedicated RESET and WDO outputs.

What is the function of the WDO pin on the TPS3851H25EDRBT?

The WDO (Watchdog Output) pin on the TPS3851H25EDRBT provides an independent open-drain fault signal that asserts low when a watchdog timeout occurs - but only when RESET is deasserted (high). This allows the system to log or respond to software hangs without triggering a full hardware reset, preserving RAM contents and communication state. WDO remains high-impedance when RESET is low.

Is the TPS3851H25EDRBT compatible with 1.8 V logic interfaces?

Yes - the TPS3851H25EDRBT supports VDD down to 1.6 V and features logic-compatible input thresholds: VIH(MR/SET1) = 0.8 V, VIL = 0.25 V, and WDI accepts 0.3×VDD to 0.8×VDD thresholds. When powered from 1.8 V, MR and SET1 operate reliably with standard 1.8 V CMOS levels, and WDO/RESET open-drain outputs interface cleanly with 1.8 V pullups.