Texas Instruments TPS3851H33EDRBR

Overview

TPS3851H33EDRBR 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 applications. It delivers 0.8% undervoltage threshold accuracy over –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 on 1.6V–6.5V supply rails.

For engineers reviewing the TPS3851H33EDRBR datasheet, TPS3851H33EDRBR pinout, TPS3851H33EDRBR application, or TPS3851H33EDRBR equivalent, this device serves as a high-accuracy supervisory solution where tight supply tolerance, glitch-immune reset assertion, and configurable watchdog behavior are critical - especially in industrial IoT edge nodes and safety-aware embedded systems.

Technical Context

The TPS3851H33EDRBR implements a precision bandgap-referenced comparator for undervoltage detection with 0.5% hysteresis and ±0.8% VITN accuracy across temperature. Its reset delay uses an internal RC timing circuit achieving ±15% tolerance, eliminating need for external timing components.

Watchdog functionality operates independently of RESET: WDO asserts low for tRST duration upon timeout while RESET remains high, enabling diagnostic flagging without full system reset. Timing is selectable via CWD pin configuration (capacitor, 10kΩ pullup, or open) and SET1 logic control - supporting both standard (170–230 ms) and extended (1.36–1.84 s) factory presets.

Key Specifications

Pinout & Package

TPS3851H33EDRBR 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 applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G33EDRBR and MAX6373KA33+T, the TPS3851H33EDRBR uniquely combines 4% UVLO accuracy, independent WDO signaling, and capacitor-programmable watchdog timing - making it the only option that satisfies simultaneous requirements for tight trip-point control, layered fault response, and hardware-configurable supervision in industrial edge devices.

Availability

TPS3851H33EDRBR is available at Aetrix Electronics and suitable for WLAN access points, wireless security cameras, IP network cameras, and string inverter control units requiring stable component supply across extended temperature and long product lifecycles.

Supply support for TPS3851H33EDRBR 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 industrial and automotive-grade components.

The TPS3851H33EDRBR belongs to TI's precision voltage supervisor family, engineered specifically for mission-critical embedded systems demanding sub-1% threshold accuracy, independent watchdog signaling, and robust operation from –40°C to +125°C.

FAQ

What is the undervoltage threshold (VITN) for TPS3851H33EDRBR?

The TPS3851H33EDRBR has a nominal 3.3V supply monitoring capability with a 4% undervoltage lockout threshold, resulting in VITN = 3.168V (3.3V × 0.96). This value is factory-trimmed to ±0.8% accuracy across –40°C to +125°C, confirmed in the Electrical Characteristics table of the SBVS300B datasheet. The TPS3851H33EDRBR achieves this precision using a bandgap-referenced comparator with built-in hysteresis.

How does the watchdog timeout work on TPS3851H33EDRBR?

The TPS3851H33EDRBR supports two watchdog timeout modes: factory-programmed (via CWD pin open or 10kΩ pullup to VDD) and user-programmable (via external capacitor on CWD). With SET1 = high, open CWD yields 1.36–1.84 s timeout; 10kΩ pullup yields 170–230 ms. Capacitor timing follows tWD = 3.23 × CCWD(nF) + 0.381 ms (standard) or extended variants. The TPS3851H33EDRBR asserts WDO low for tRST (200 ms) upon timeout while RESET remains high.

Can TPS3851H33EDRBR monitor multiple voltage rails?

No - the TPS3851H33EDRBR monitors only the VDD supply rail directly. It does not include auxiliary sense inputs or multi-rail comparators. For systems requiring supervision of multiple rails (e.g., 1.2V, 3.3V, 5V), separate TPS3851H33EDRBR units or multi-channel supervisors like TPS386000 are required. The TPS3851H33EDRBR's design focuses on high-accuracy single-rail monitoring with integrated watchdog, not multi-voltage tracking.

What is the function of the SET1 pin on TPS3851H33EDRBR?

The SET1 pin on TPS3851H33EDRBR controls watchdog enable/disable: grounding SET1 disables the watchdog timer entirely, causing WDI to be ignored and WDO to remain high-impedance. When SET1 is high, watchdog operation resumes. This feature allows safe development-mode operation and dynamic watchdog control - for example, disabling during bootloader execution or firmware update phases. The TPS3851H33EDRBR requires WDI to be driven to VDD or GND when watchdog is disabled to prevent increased IDD.

Is TPS3851H33EDRBR compatible with 1.8V logic systems?

Yes - the TPS3851H33EDRBR operates with VDD as low as 1.6V and supports input logic thresholds scaled to VDD (e.g., VIH(WDI) = 0.8 × VDD). Its open-drain RESET and WDO outputs are compatible with 1.8V pullup rails when configured with appropriate external resistors (1kΩ–100kΩ). The TPS3851H33EDRBR's 0.8% VITN accuracy and 0.5% hysteresis ensure reliable supervision even at 1.8V nominal rails, as validated in TI's typical characteristics data (Figures 5-7, 5-9).