Texas Instruments TPS3851H18EQDRBRQ1

Overview

TPS3851H18EQDRBRQ1 from Texas Instruments is a high-accuracy AEC-Q100 Grade 1 automotive voltage supervisor with integrated watchdog timer, featuring 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), and user-programmable or factory-set watchdog timeouts up to 1.84 s. It monitors 1.8 V rails in ADAS domain controllers and front camera power supplies.

For engineers reviewing the TPS3851H18EQDRBRQ1 datasheet, TPS3851H18EQDRBRQ1 pinout, TPS3851H18EQDRBRQ1 application, or TPS3851H18EQDRBRQ1 equivalent, key selection criteria include its ±0.5% hysteresis, 10 µA supply current, open-drain RESET/WDO outputs, MR input for manual reset, and CWD/SET1 configuration flexibility for watchdog timing control.

Technical Context

The TPS3851H18EQDRBRQ1 implements a precision bandgap-based comparator for undervoltage detection on the VDD rail, with factory-trimmed 1.728 V threshold (H18 variant) and 0.5% hysteresis. Its internal state machine evaluates CWD pin configuration (capacitor, 10 kΩ pullup, or open) at power-up to select watchdog timing mode-standard (170–230 ms) or extended (1.36–1.84 s)-with SET1 enabling/disabling.

It integrates independent open-drain outputs: RESET asserts when VDD falls below VITN and remains low for tRST after recovery; WDO asserts only when RESET is high and watchdog timeout occurs, providing fault isolation without full system reset. MR input supports external reset initiation with internal 620 nA pullup.

Key Specifications

Pinout & Package

TPS3851H18EQDRBRQ1 is housed in a 3.00 mm × 3.00 mm, 8-pin VSON package (DRB) with wettable flanks for optical solder inspection. Thermal pad is internally connected to GND and must be soldered to a large-area ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3851G18EQDRBRQ1 and MAX6373KA21+T, the TPS3851H18EQDRBRQ1 delivers superior threshold accuracy (0.8% vs. 3.5%), tighter hysteresis (0.5% vs. 4%), and true dual-output fault signaling-making it the only option qualified for high-integrity automotive vision systems requiring deterministic reset and watchdog behavior.

Availability

TPS3851H18EQDRBRQ1 is available at Aetrix Electronics and suitable for automotive ADAS domain controllers, surround-view ECUs, and front camera modules requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-compliant sourcing.

Supply support for TPS3851H18EQDRBRQ1 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 deep expertise in automotive-grade IC design and functional safety certification.

The TPS3851-Q1 product line was developed specifically for ASIL-B automotive safety applications, integrating precision supervision and configurable watchdog functionality into a single AEC-Q100 Grade 1 device for next-generation ADAS and cockpit electronics.

FAQ

What is the exact undervoltage threshold voltage of the TPS3851H18EQDRBRQ1?

The TPS3851H18EQDRBRQ1 has a factory-programmed undervoltage threshold (VITN) of 1.728 V, corresponding to a nominal 1.8 V rail with 0.8% accuracy over –40°C to +125°C. This value is trimmed during production and documented in TI's SBVS286B datasheet revision July 2025. The hysteresis is fixed at 0.5% of VITN, yielding 8.64 mV.

How does the CWD pin configure watchdog timing on the TPS3851H18EQDRBRQ1?

The CWD pin on the TPS3851H18EQDRBRQ1 selects watchdog mode via three configurations: unconnected (enables extended timing: 1.36–1.84 s), pulled to VDD with 10 kΩ (enables standard timing: 170–230 ms), or connected to GND via capacitor (user-programmable timing per Equation 1/2). The device samples CWD at power-up during a 381 µs evaluation window.

Can the TPS3851H18EQDRBRQ1 be used without connecting the WDI pin?

Yes-the WDI pin may be left unconnected only if the watchdog is disabled via SET1 = GND. When watchdog is active, WDI must be driven to VDD or GND at all times; floating WDI increases supply current (IDD) due to internal logic gate ambiguity. TI specifies this in Section 6.3.4.2 of the SBVS286B datasheet.

What is the purpose of the SET1 pin on the TPS3851H18EQDRBRQ1?

The SET1 pin on the TPS3851H18EQDRBRQ1 controls watchdog enable/disable: logic low (GND) disables the watchdog entirely and ignores WDI, while logic high enables normal watchdog operation. This allows safe firmware development without unintended timeouts. A 150 µs setup time applies when transitioning from disabled to enabled state.

Does the TPS3851H18EQDRBRQ1 support functional safety certification?

Yes-the TPS3851H18EQDRBRQ1 is functional safety-capable with documentation available to aid ISO 26262 system-level design. It is AEC-Q100 Grade 1 qualified (–40°C to +125°C), features 0.8% VITN accuracy, 15% tRST accuracy, and independent WDO/RESET outputs to support ASIL-B fault containment strategies per TI's safety manual SLVSBX9.