Texas Instruments TPS3851H33SQDRBRQ1

Overview

TPS3851H33SQDRBRQ1 from Texas Instruments is a high-accuracy automotive-grade voltage supervisor IC with integrated programmable watchdog timer, 0.8% undervoltage threshold accuracy over –40°C to +125°C, 200 ms reset timeout (±15%), and open-drain RESET/WDO outputs. It monitors 3.3V supply rails in ADAS domain controllers and front camera modules.

For engineers reviewing the TPS3851H33SQDRBRQ1 datasheet, TPS3851H33SQDRBRQ1 pinout, TPS3851H33SQDRBRQ1 application, or TPS3851H33SQDRBRQ1 equivalent, key selection criteria include AEC-Q100 Grade 1 qualification, factory-programmed 1600 ms watchdog timeout (H33 variant), 10 µA typical supply current, 0.5% hysteresis, and VSON-8 wettable flanks package for automated optical inspection.

Technical Context

The TPS3851H33SQDRBRQ1 implements a precision bandgap-based comparator for undervoltage detection and a state-machine-controlled watchdog timer with dual timing modes (standard/extended). Its RESET delay uses a trimmed RC oscillator achieving ±15% accuracy across temperature, while the watchdog timeout is determined either by internal factory programming (H33 = 1.6 s typ) or external capacitor on CWD pin.

It features independent open-drain outputs: RESET asserts when VDD falls below 3.3V ±0.8% (VITN = 3.3V), with 0.5% hysteresis; WDO asserts only when RESET is deasserted and watchdog timeout occurs, enabling fault isolation without full system reset. SET1 and MR pins provide hardware control of watchdog enable and manual reset initiation.

Key Specifications

Pinout & Package

TPS3851H33SQDRBRQ1 is housed in a 3.00 mm × 3.00 mm, 8-pin VSON package with wettable flanks for solder joint 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 TPS3851G33SQDRBRQ1 and MAX6373KA33+T, the TPS3851H33SQDRBRQ1 uniquely delivers 0.8% threshold accuracy, factory-programmed 1600 ms watchdog, and dual open-drain outputs-making it the only option qualified for ASIL-B–capable ADAS subsystems requiring both precision supervision and fault-diagnostic granularity.

Availability

TPS3851H33SQDRBRQ1 is available at Aetrix Electronics and suitable for ADAS domain controllers, automotive front cameras, surround view ECUs, and vehicle occupant detection sensors requiring stable component supply across extended automotive lifecycles.

Supply support for TPS3851H33SQDRBRQ1 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 designing analog and embedded processing solutions for automotive, industrial, and personal electronics markets.

The TPS3851-Q1 product line delivers AEC-Q100–qualified voltage supervisors with integrated watchdog timers specifically for functional safety–critical automotive systems including ADAS, body electronics, and infotainment.

FAQ

What is the exact undervoltage threshold voltage for TPS3851H33SQDRBRQ1?

The TPS3851H33SQDRBRQ1 has a nominal undervoltage threshold (V_ITN) of 3.3 V with ±0.8% accuracy over –40°C to +125°C. This is factory-trimmed and verified per AEC-Q100 Grade 1 requirements. The actual threshold for any given unit falls between 3.2736 V and 3.3264 V at 25°C, and remains within this tolerance band across the full operating temperature range.

Does TPS3851H33SQDRBRQ1 require an external capacitor for watchdog timing?

No, the TPS3851H33SQDRBRQ1 does not require an external capacitor for watchdog timing. As an H33 variant, it uses factory-programmed timing with a typical watchdog timeout of 1600 ms. The CWD pin must be left unconnected or pulled up to VDD via a 10 kΩ resistor to select this default setting. External capacitors are only needed for user-adjustable timing variants.

How does the SET1 pin affect watchdog operation in TPS3851H33SQDRBRQ1?

In the TPS3851H33SQDRBRQ1, grounding the SET1 pin disables the watchdog timer entirely, causing WDI to be ignored and WDO to remain high-impedance. When SET1 is pulled high (≥0.8×VDD), the watchdog operates using the timing selected by CWD configuration. A 150 µs setup time applies when transitioning from disabled to enabled state.

What is the purpose of the wettable flanks on the TPS3851H33SQDRBRQ1 VSON package?

Wettable flanks on the TPS3851H33SQDRBRQ1's 3 mm × 3 mm VSON package expose solderable metal along the vertical side walls of the package. This enables automated optical inspection (AOI) systems to verify solder joint quality and coplanarity after reflow-critical for zero-defect manufacturing in automotive electronics where field reliability is mandated by ISO/TS 16949.

Can TPS3851H33SQDRBRQ1 monitor supply rails other than 3.3V?

Yes, the TPS3851H33SQDRBRQ1 can monitor supply rails from 1.8 V to 5.0 V, though its V_ITN is fixed at 3.3 V. For rails outside 3.3 V, external resistor dividers must be used to scale the monitored voltage to match the 3.3 V threshold. The device's 1.6 V to 6.5 V VDD operating range supports such configurations, and its 0.5% hysteresis maintains stability even with divider network tolerances.