Texas Instruments TPS3851H18EDRBT

Overview

TPS3851H18EDRBT from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for system-level power monitoring and fault recovery in microcontroller-based embedded systems. It delivers 0.8% undervoltage threshold accuracy over –40°C to +125°C, 200 ms reset timeout (±15%), and user-programmable watchdog timing via CWD pin - enabling reliable startup supervision and runtime fault detection in 1.8V rail applications such as IP cameras and string inverters.

For engineers reviewing the TPS3851H18EDRBT datasheet, TPS3851H18EDRBT pinout, TPS3851H18EDRBT application, or TPS3851H18EDRBT equivalent, this page provides verified functional specifications, validated pin functions, confirmed thermal and timing behavior, and real-world implementation context for industrial-grade power sequencing and watchdog validation.

Technical Context

The TPS3851H18EDRBT implements a high-accuracy comparator architecture with built-in 0.5% hysteresis and factory-trimmed reference, ensuring stable undervoltage detection on 1.8V supply rails across automotive-grade temperature extremes. Its dual-output open-drain structure separates RESET (system reset) and WDO (watchdog fault flag), allowing independent handling of power faults versus software hangs.

Watchdog timing is determined by CWD pin configuration: unconnected or pulled up enables factory-programmed 1.6 s (standard) or 200 ms (extended) timeouts; capacitor-connected enables continuous adjustment (0.7 ms to 77 s). SET1 disables the watchdog entirely, while MR supports manual reset initiation with internal pullup - all operating within 1.6–6.5 V supply range and 10 µA typical quiescent current.

Key Specifications

Pinout & Package

TPS3851H18EDRBT is housed in an 8-pin VSON package (DRB) with 3.00 mm × 3.00 mm body size and exposed thermal pad connected internally to GND. The thermal pad must be soldered to a large-area ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851H18EDRBT, the G18 variant offers identical form factor and timing but reduced hysteresis control, while the MAX6373 provides simpler reset-only supervision in legacy SO-8 layout - neither matches the combined precision, programmability, and compactness of the TPS3851H18EDRBT for modern 1.8V embedded systems.

Availability

TPS3851H18EDRBT is available at Aetrix Electronics and suitable for WLAN access points, IP network cameras, string inverters, blood pressure monitors, and electricity meters requiring stable component supply across extended temperature and long product lifecycles.

Supply support for TPS3851H18EDRBT 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 precision power management and reliability-critical IC design.

The TPS3851H18EDRBT belongs to TI's high-accuracy voltage supervisor family, engineered specifically for industrial, medical, and communications equipment demanding guaranteed reset behavior and configurable fault recovery under extreme thermal and electrical stress.

FAQ

What is the exact undervoltage threshold voltage (VITN) for TPS3851H18EDRBT?

The TPS3851H18EDRBT has a nominal undervoltage threshold of 1.728 V, corresponding to a 1.8 V supply rail with 4% undervoltage detection. This value is factory-trimmed and achieves ±0.8% accuracy across –40°C to +125°C, as confirmed in the device's electrical characteristics table and typical accuracy plots. The 1.728 V threshold ensures reset assertion before the monitored 1.8 V rail falls below its minimum operational specification.

How does the CWD pin configure watchdog timing on TPS3851H18EDRBT?

The CWD pin on TPS3851H18EDRBT selects watchdog timeout mode: unconnected or pulled up with 10 kΩ to VDD enables factory-programmed 1600 ms (standard) or 200 ms (extended) timeouts; connecting a capacitor to GND enables user-adjustable timing per tWD = 3.23 × CCWD + 0.381 ms (standard) or tWD = 287 × CCWD + 62.7 ms (extended). The device evaluates CWD state within 381 µs after VDD enters valid range.

Can TPS3851H18EDRBT monitor a 1.8 V rail while powered from a higher voltage?

Yes - TPS3851H18EDRBT monitors its own VDD supply, so it must be powered directly from the 1.8 V rail it supervises. Its 1.6–6.5 V operating range accommodates 1.8 V nominal with margin for ripple and droop. It does not support remote sensing; VDD is both supply and monitored rail. For higher-supply monitoring, a resistor divider is not supported - use a dedicated supervisor with external sense input.

What is the function of the SET1 pin on TPS3851H18EDRBT?

The SET1 pin on TPS3851H18EDRBT enables or disables the watchdog timer: grounding SET1 disables watchdog functionality and causes WDI to be ignored, while pulling SET1 high enables normal watchdog operation. This allows safe firmware development and field updates without unintended resets. When disabled, WDI must be driven to VDD or GND to avoid increased IDD.

Does TPS3851H18EDRBT support manual reset, and how is it implemented?

Yes - TPS3851H18EDRBT includes a dedicated MR (manual reset) pin (Pin 3) that asserts RESET when driven low. MR has an internal 620 nA pullup current, so it can be left floating or tied to VDD if unused. RESET remains low for the full 200 ms tRST period after MR is released, ensuring reliable processor reset. Propagation delay from MR to RESET is 200 ns maximum.