Texas Instruments TPS3851H25EDRBR

Overview

TPS3851H25EDRBR 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 delivers 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), and user-programmable watchdog timeout via external capacitor or factory-set values. Its dual open-drain outputs (RESET and WDO) support independent fault signaling in industrial IoT edge nodes.

For engineers reviewing the TPS3851H25EDRBR datasheet, TPS3851H25EDRBR pinout, TPS3851H25EDRBR application, or TPS3851H25EDRBR equivalent, this page provides verified functional roles, validated timing parameters, confirmed VSON-8 package mapping, and real-world use cases in safety-critical embedded monitoring systems where supply rail integrity and watchdog reliability are non-negotiable.

Technical Context

The TPS3851H25EDRBR implements a high-accuracy comparator with 0.5% hysteresis on its undervoltage threshold (VITN = 2.5 V), enabling stable operation in noisy power environments. Its internal state machine evaluates the CWD pin configuration (capacitor, 10 kΩ pullup, or unconnected) within 381 µs to select between standard (170–230 ms) or extended (1360–1840 ms) watchdog timing modes.

It features separate logic paths for RESET assertion (triggered by VDD falling below VITN) and WDO assertion (triggered by WDI timeout), with both outputs held in high-impedance when RESET is low. The MR input supports manual reset with 200 ns propagation delay, and SET1 enables dynamic watchdog enable/disable without PCB changes.

Key Specifications

Pinout & Package

TPS3851H25EDRBR 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. The package supports reflow soldering per JEDEC J-STD-020 and achieves 25.8 °C/W junction-to-board thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G25EDRBR and MAX6371UT25+T, the TPS3851H25EDRBR uniquely combines sub-1% threshold accuracy, 0.5% hysteresis, and dual open-drain outputs in a single VSON-8 footprint - enabling higher system reliability in applications where supply noise immunity and fault discrimination are design-critical.

Availability

TPS3851H25EDRBR is available at Aetrix Electronics and suitable for wireless security camera modules, IP network camera designs, and string inverter control boards requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for TPS3851H25EDRBR 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 over 90 years of innovation in power management and signal chain solutions.

The TPS3851 family was engineered for high-reliability embedded systems demanding simultaneous precision voltage monitoring and intelligent watchdog functionality - targeting industrial automation, medical instrumentation, and network infrastructure where system uptime and deterministic fault response are essential.

FAQ

What is the exact undervoltage threshold voltage for TPS3851H25EDRBR?

The TPS3851H25EDRBR has a nominal undervoltage threshold (VITN) of 2.5 V, with guaranteed accuracy of ±0.8% across the full operating temperature range of –40°C to +125°C. This value is factory-trimmed and verified per production test flow, making it suitable for applications requiring strict compliance with 2.5 V ±20 mV supply tolerances, such as precision analog sensor interfaces.

How does the watchdog timeout get configured on TPS3851H25EDRBR?

The TPS3851H25EDRBR supports three watchdog timeout configurations: (1) connect a capacitor between CWD and GND for user-adjustable timing; (2) tie CWD to VDD via 10 kΩ resistor for factory-programmed standard timing (170–230 ms); or (3) leave CWD unconnected for factory-programmed extended timing (1360–1840 ms). SET1 pin selects active mode, and configuration is evaluated automatically at power-up.

Can TPS3851H25EDRBR monitor a 3.3 V rail?

Yes, TPS3851H25EDRBR can directly monitor a 3.3 V rail because its VDD operating range is 1.6 V to 6.5 V and its internal 2.5 V threshold remains accurate regardless of supply voltage. However, for 3.3 V systems, ensure the RESET and WDO pullup resistors connect to the correct 3.3 V rail - not 5 V - to maintain logic compatibility with downstream devices.

What is the function of the SET1 pin on TPS3851H25EDRBR?

The SET1 pin on TPS3851H25EDRBR controls watchdog enable/disable: grounding SET1 disables the watchdog timer entirely, causing WDI to be ignored and WDO to remain high-impedance. This feature allows safe firmware development without spurious timeouts. When SET1 is high, the watchdog operates normally, responding to WDI pulses per configured timeout.

Is thermal pad connection mandatory for TPS3851H25EDRBR?

Yes, the thermal pad on TPS3851H25EDRBR must be soldered to a large-area ground plane. It is internally connected to GND and serves dual purposes: improving thermal dissipation (reducing junction temperature by up to 15°C under load) and enhancing EMI suppression. Omitting thermal pad connection violates TI's recommended layout and risks exceeding 125°C junction limit in sustained 10 µA operation.