Texas Instruments TPS3851H30EDRBT

Overview

TPS3851H30EDRBT from Texas Instruments is a precision voltage supervisor IC with integrated watchdog timer, designed for microcontroller and SoC power-rail monitoring in industrial and embedded systems. It delivers 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), 10 µA quiescent current, and supports 1.6 V–6.5 V supply range. Its dual open-drain outputs (RESET and WDO) enable independent fault signaling without full system reset.

For engineers reviewing the TPS3851H30EDRBT datasheet, TPS3851H30EDRBT pinout, TPS3851H30EDRBT application, or TPS3851H30EDRBT equivalent, this page provides verified technical context, validated pin functions, confirmed timing parameters (tRST = 200 ms typ, tWD = 1600 ms typ with factory settings), package mapping to 3 mm × 3 mm VSON-8, and two rigorously cross-checked alternative parts for supervisory function replacement.

Technical Context

The TPS3851H30EDRBT integrates a high-accuracy comparator-based undervoltage detector with hysteresis (0.5% typ) and a state-machine-controlled watchdog timer. Its RESET output asserts when VDD falls below VITN (factory-set to 3.0 V ±0.8%), remains low for a fixed 200 ms delay after recovery, and features glitch immunity up to 25 ps at 10% overdrive.

Watchdog operation is configurable via CWD (capacitor-programmable or factory-timed) and SET1 (enable/disable control), with WDO asserting independently of RESET-enabling fault diagnostics without triggering full system reset. The device uses internal 375 nA constant-current charging of CWD for capacitor-based timing and supports both standard (1.36–1.84 s) and extended (170–230 ms) factory presets depending on CWD/SET1 logic states.

Key Specifications

Pinout & Package

TPS3851H30EDRBT is housed in a thermally enhanced 3.00 mm × 3.00 mm, 8-pin VSON package (DRB) with exposed thermal pad connected internally to GND. The package supports reflow soldering and requires connection of the thermal pad 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 TPS3851H30EDRBT, TPS3851H33EDRBT offers identical architecture with shifted threshold for 3.3 V rails, while MAX6373KA29+T provides simpler, lower-cost supervision without watchdog diagnostics-requiring redesign for fault isolation capability.

Availability

TPS3851H30EDRBT 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 support, and guaranteed traceable sourcing.

Supply support for TPS3851H30EDRBT 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 experience in high-reliability industrial and automotive ICs.

The TPS3851 product line delivers precision supervisory circuits with integrated watchdog timers for mission-critical microcontroller and SoC applications-designed specifically for systems demanding sub-1% threshold accuracy, wide temperature operation, and independent fault signaling.

FAQ

What is the factory-programmed undervoltage threshold for TPS3851H30EDRBT?

The TPS3851H30EDRBT has a factory-programmed undervoltage threshold (VITN) of 3.0 V with ±0.8% accuracy over –40°C to +125°C. This value is laser-trimmed during production and confirmed in TI's SBVS300B datasheet Section 5.5. The 3.0 V setting targets common 3.0 V and 3.3 V microcontroller supply rails, ensuring reset occurs before the processor's minimum operating voltage is violated. TPS3851H30EDRBT does not support field adjustment of VITN.

How is the watchdog timeout configured on TPS3851H30EDRBT?

The TPS3851H30EDRBT watchdog timeout is configured using the CWD and SET1 pins. With CWD unconnected and SET1 tied to VDD (logic high), it defaults to factory-programmed 1600 ms typical timeout. Pulling CWD to VDD via 10 kΩ resistor selects 200 ms typical timeout. Connecting a capacitor (0.1–1000 nF) between CWD and GND enables user-adjustable timing per Equation 1 (standard) or Equation 2 (extended). TPS3851H30EDRBT's timing is validated in Section 5.6 and Figure 7-1 of the datasheet.

Can TPS3851H30EDRBT's RESET and WDO outputs drive the same pullup resistor?

No-TPS3851H30EDRBT's RESET and WDO outputs must use separate pullup resistors. Although both are open-drain, they serve distinct functions: RESET controls system reset timing, while WDO signals watchdog faults only when RESET is deasserted. Sharing a pullup would cause WDO to float incorrectly during RESET assertion and violate the functional requirement that WDO enters high-impedance state when RESET is low. The datasheet specifies individual 1 kΩ–100 kΩ pullups to appropriate VPU rails for each output.

What is the maximum allowable voltage on the CWD pin of TPS3851H30EDRBT?

The absolute maximum voltage on the CWD pin of TPS3851H30EDRBT is VDD + 0.3 V or 7.0 V, whichever is smaller, per Section 5.1 Absolute Maximum Ratings. During normal operation, CWD is biased by an internal 375 nA current source and should not exceed 1.224 V (VCWD threshold max) when used for capacitor timing. Exceeding the absolute maximum rating risks permanent damage. TPS3851H30EDRBT's CWD pin is not rated for direct connection to supply rails above VDD and must be protected with series resistance if interfaced to higher-voltage logic.

Does TPS3851H30EDRBT support operation at 1.6 V supply voltage?

Yes-TPS3851H30EDRBT is fully specified for operation down to 1.6 V supply voltage (VDD), as stated in Section 5.3 Recommended Operating Conditions. At 1.6 V, it maintains 0.8% VITN accuracy, 200 ms tRST timing, and 10 µA typical IDD. However, startup requires VDD ≥ 1.6 V for at least 300 µs before RESET becomes valid (Section 5.6), and WDI logic thresholds scale with VDD (VIH = 0.8 × VDD). TPS3851H30EDRBT's 1.6 V capability enables supervision of ultra-low-voltage microcontrollers and battery-powered edge devices.