Texas Instruments TPS3851G18EDRBR

Overview

TPS3851G18EDRBR 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%), and user-programmable watchdog timeout via CWD pin capacitor or factory-set values. Its 1.8 V fixed undervoltage threshold (VITN = 1.728 V) supports 1.8 V logic rails in Wi-Fi access points and IP cameras.

For engineers reviewing the TPS3851G18EDRBR datasheet, TPS3851G18EDRBR pinout, TPS3851G18EDRBR application, or TPS3851G18EDRBR equivalent, this page provides verified technical context, exact pin functions, real-world use cases for tight-tolerance systems, and validated alternative parts - all grounded in TI's SBVS300B production data sheet.

Technical Context

The TPS3851G18EDRBR implements a high-accuracy comparator-based undervoltage detection circuit with 0.5% hysteresis and a dedicated state machine for independent watchdog timing control. Its RESET output asserts when VDD falls below 1.728 V and remains low for 200 ms after VDD rises above 1.728 V + hysteresis, ensuring reliable microcontroller initialization.

Watchdog functionality operates independently of RESET: WDO asserts on timeout only when RESET is deasserted (high), enabling fault isolation without full system reset. Timing is selected via CWD pin configuration (capacitor, 10 kΩ pullup, or open) and SET1 pin (GND = disable, VDD = enable), supporting both development flexibility and production repeatability.

Key Specifications

Pinout & Package

TPS3851G18EDRBR uses a 3.00 mm × 3.00 mm, 8-pin VSON package (DRB) with exposed thermal pad internally connected to GND. The thermal pad must be soldered to a large-area ground plane for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G18EDRBR, the DBVR variant sacrifices watchdog independence and pin count for smaller footprint, while the MAX6373 offers lower cost at the expense of accuracy and configurability - making TPS3851G18EDRBR optimal for designs demanding precision, diagnostics, and field-upgradeable timing.

Availability

TPS3851G18EDRBR is available at Aetrix Electronics and suitable for WLAN access points, IP network cameras, and string inverter control boards requiring stable component supply across extended temperature and long product lifecycles.

Supply support for TPS3851G18EDRBR 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 industrial ICs.

The TPS3851 family is engineered for precision power-supply monitoring in mission-critical embedded systems, combining high-accuracy voltage thresholds, independent watchdog signaling, and robust operation from –40°C to +125°C.

FAQ

What is the exact undervoltage threshold voltage for TPS3851G18EDRBR?

The TPS3851G18EDRBR has a factory-trimmed undervoltage threshold (VITN) of 1.728 V, corresponding to a nominal 1.8 V supply rail. This value is guaranteed within ±0.8% over the full –40°C to +125°C junction temperature range, as confirmed in TI's SBVS300B datasheet Section 5.5.

Does TPS3851G18EDRBR support both standard and extended watchdog timing modes?

Yes, TPS3851G18EDRBR supports both modes. Standard timing yields ~1600 ms watchdog timeout with factory settings (CWD open, SET1 high), while extended timing gives ~200 ms. The mode is determined by internal configuration - no external part number suffix distinguishes them, and both are accessible via CWD/SET1 pin states per Section 7.1.1.1.

Can TPS3851G18EDRBR be used to supervise a 3.3 V rail?

No - TPS3851G18EDRBR is specifically the 1.8 V threshold variant (G18 suffix). For 3.3 V supervision, TI offers TPS3851G33 variants. Using TPS3851G18EDRBR on a 3.3 V rail would assert RESET continuously since 3.3 V exceeds its 1.728 V VITN by >90%, violating intended operation.

What is the function of the thermal pad on the TPS3851G18EDRBR VSON package?

The exposed thermal pad on the TPS3851G18EDRBR DRB package is internally connected to GND and must be soldered to a large-area PCB ground plane. It reduces junction-to-board thermal resistance (RθJB = 25.8°C/W) and improves long-term reliability in thermally stressed applications like enclosed IP cameras or inverters.

How does the manual reset (MR) pin behave when left unconnected?

When left unconnected, the MR pin of TPS3851G18EDRBR remains at logic high due to its internal pullup current (500–700 nA), so it does not trigger RESET. This allows MR to be omitted from the schematic unless active reset initiation is required - simplifying design for applications needing only power-on supervision.