Texas Instruments TPS3851G25EDRBT

Overview

TPS3851G25EDRBT 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 settings. Its dual open-drain outputs (RESET and WDO) support independent fault signaling in industrial and embedded systems.

For engineers reviewing the TPS3851G25EDRBT datasheet, TPS3851G25EDRBT pinout, TPS3851G25EDRBT application, or TPS3851G25EDRBT equivalent, this page provides verified functional roles, validated timing parameters, confirmed VSON-8 package mapping, and real-world use cases in IP cameras, string inverters, and medical monitors - all derived from TI's SBVS300B production datasheet.

Technical Context

The TPS3851G25EDRBT implements a high-accuracy comparator with 0.5% hysteresis and a dedicated state machine for watchdog timing evaluation. Its CWD pin supports three configuration modes: unconnected (factory default), 10 kΩ pullup to VDD (fixed timeout), or capacitor-to-GND (user-adjustable timeout), with initialization completed within 381 µs after VDD enters the valid operating range.

It features separate logic paths for RESET assertion (triggered by VDD falling below VITN = 2.5 V ± 0.8%) and WDO assertion (triggered by WDI edge violation), both synchronized to a precision internal clock. The MR input enables manual reset with 200 ns propagation delay, while SET1 provides dynamic watchdog enable/disable control with 150 µs setup time.

Key Specifications

Pinout & Package

TPS3851G25EDRBT is housed in an 8-pin VSON package (DRB), measuring 3.00 mm × 3.00 mm with exposed thermal pad connected internally to GND. The package supports reflow soldering and provides low thermal resistance (R_θJB = 25.8 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G25EDRBT, the G33 and G50 variants retain identical watchdog functionality, timing accuracy, and thermal performance but differ solely in factory-set VITN thresholds - making them functionally interchangeable only when the target supply rail matches their respective threshold voltage.

Availability

TPS3851G25EDRBT is available at Aetrix Electronics and suitable for IP network cameras, string inverters, and blood pressure monitors requiring stable component supply, long-term lifecycle support, and automotive-grade temperature resilience.

Supply support for TPS3851G25EDRBT 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 engineered for mission-critical power supervision in industrial, medical, and communications equipment, delivering precision voltage monitoring and configurable watchdog protection in compact VSON packages.

FAQ

What is the exact undervoltage threshold voltage for TPS3851G25EDRBT?

The TPS3851G25EDRBT has a factory-programmed undervoltage threshold (VITN) of 2.5 V with ±0.8% accuracy across –40°C to +125°C, as specified in TI's SBVS300B datasheet Section 5.5. This value is laser-trimmed during production and applies to the G25 variant specifically - distinct from G18 (1.8 V), G33 (3.3 V), or G50 (5.0 V) versions. The 0.5% hysteresis ensures stable release above 2.5125 V.

How does the watchdog timeout work on TPS3851G25EDRBT when CWD is left unconnected?

When the CWD pin of the TPS3851G25EDRBT is left unconnected (high-impedance), the device selects the factory-programmed standard timing mode with a typical watchdog timeout of 1600 ms (min 1360 ms, max 1840 ms), as documented in SBVS300B Table 7-1. This mode requires SET1 = 1 (logic high) and provides ±15% timing accuracy without external components - ideal for designs prioritizing BOM simplicity and timing predictability.

Can TPS3851G25EDRBT monitor multiple voltage rails simultaneously?

No, the TPS3851G25EDRBT monitors only the VDD supply rail it is powered from - in this case, the 2.5 V rail. It does not include auxiliary sense inputs or multi-rail comparators. To supervise additional rails (e.g., 3.3 V or 1.2 V), separate supervisors such as TPS3851G33EDRBT or TPS3851G12EDRBT must be used, each powered from and monitoring its respective rail.

What is the role of the SET1 pin on TPS3851G25EDRBT?

The SET1 pin on TPS3851G25EDRBT controls watchdog enable/disable functionality: grounding SET1 disables the watchdog timer entirely (WDO becomes inactive and WDI is ignored), while pulling SET1 high enables normal watchdog operation. This allows safe development-mode operation without unintended timeouts, and supports dynamic runtime control with a 150 µs setup time when transitioning from disabled to enabled state.

Is the thermal pad on TPS3851G25EDRBT electrically connected, and how should it be handled in layout?

Yes, the thermal pad on the TPS3851G25EDRBT is internally connected to GND. Per TI's SBVS300B datasheet Section 4 and Section 5.4, it must be soldered to a large-area ground plane to achieve specified thermal performance (R_θJB = 25.8 °C/W). Leaving it floating or connecting it to a non-ground net violates thermal and electrical specifications and may cause malfunction or reduced reliability.