Texas Instruments TPS3851H18SQDRBRQ1

Overview

TPS3851H18SQDRBRQ1 from Texas Instruments is a high-accuracy AEC-Q100 Grade 1 voltage supervisor IC with integrated programmable watchdog timer, 0.8% undervoltage threshold accuracy (–40°C to +125°C), 200 ms reset timeout (±15%), and open-drain RESET/WDO outputs. It monitors 1.8 V supply rails in automotive ADAS domain controllers and front camera modules.

For engineers reviewing the TPS3851H18SQDRBRQ1 datasheet, TPS3851H18SQDRBRQ1 pinout, TPS3851H18SQDRBRQ1 application, or TPS3851H18SQDRBRQ1 equivalent, key selection criteria include factory-programmed watchdog timing (1600 ms typ), manual reset input (MR), SET1 watchdog enable/disable control, and wettable-flank 3mm × 3mm VSON-8 packaging for automated optical inspection.

Technical Context

The TPS3851H18SQDRBRQ1 implements a precision bandgap-based comparator for undervoltage detection with 0.5% hysteresis and 35 µs propagation delay at 2.5% overdrive. Its dual-output architecture separates system reset (RESET) and fault flagging (WDO) functions, enabling independent watchdog fault diagnosis without full system reset.

Watchdog timing is determined by CWD pin configuration: unconnected or 10 kΩ pullup enables factory-programmed 1600 ms (standard) or 77.45 s (extended) timeouts; capacitor connection enables user-adjustable timing via 375 nA constant-current charge of CCWD to 1.21 V threshold. SET1 dynamically disables the watchdog, and WDI accepts falling-edge-triggered pulses with 150 µs setup time after enable.

Key Specifications

Pinout & Package

TPS3851H18SQDRBRQ1 uses 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 TPS3851H25SQDRBRQ1 and TPS3851H33SQDRBRQ1, the TPS3851H18SQDRBRQ1 provides optimal 1.728 V threshold accuracy for 1.8 V systems-substituting higher-threshold variants risks premature reset assertion or loss of undervoltage protection margin.

Availability

TPS3851H18SQDRBRQ1 is available at Aetrix Electronics and suitable for automotive ADAS domain controllers, surround-view ECUs, and front camera modules requiring stable component supply with AEC-Q100 compliance and long-term production continuity.

Supply support for TPS3851H18SQDRBRQ1 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 automotive, industrial, and power management solutions.

The TPS3851-Q1 product line delivers high-accuracy, AEC-Q100-qualified supervisors with integrated watchdog timers specifically for automotive safety-critical ECUs where precise power-rail monitoring and fault-detection timing are essential.

FAQ

What is the undervoltage threshold voltage of the TPS3851H18SQDRBRQ1?

The TPS3851H18SQDRBRQ1 has a nominal undervoltage threshold of 1.728 V, corresponding to a 4% undervoltage lockout on a 1.8 V rail. This value is guaranteed within ±0.8% over the full –40°C to +125°C operating temperature range, as confirmed in the device's electrical characteristics table and typical accuracy histograms.

Does the TPS3851H18SQDRBRQ1 support both factory-programmed and user-adjustable watchdog timing?

Yes, the TPS3851H18SQDRBRQ1 supports both modes. Leaving the CWD pin unconnected or pulling it up with a 10 kΩ resistor selects factory-programmed timing (1600 ms typical for standard mode). Connecting a capacitor from CWD to GND enables user-adjustable timing using a 375 nA constant-current source charging the capacitor to 1.21 V.

What is the function of the SET1 pin on the TPS3851H18SQDRBRQ1?

The SET1 pin on the TPS3851H18SQDRBRQ1 controls watchdog enable/disable functionality. When SET1 is grounded, the watchdog timer is disabled and the WDI input is ignored. When SET1 is pulled high, the watchdog operates normally. The pin supports dynamic toggling, with a 150 µs setup time required after enabling before WDI is recognized.

Can the TPS3851H18SQDRBRQ1 be used to monitor supply rails other than 1.8 V?

No-the TPS3851H18SQDRBRQ1 is factory-trimmed for a 1.728 V threshold optimized for 1.8 V rails. While its VDD input accepts 1.6 V–6.5 V, the undervoltage detection threshold is fixed and not adjustable. For 2.5 V or 3.3 V rails, TI offers pin-compatible variants like TPS3851H25SQDRBRQ1 and TPS3851H33SQDRBRQ1.

What package type and dimensions does the TPS3851H18SQDRBRQ1 use?

The TPS3851H18SQDRBRQ1 uses a 3.00 mm × 3.00 mm, 8-pin VSON package (DRB suffix) with wettable flanks. The thermal pad is internally connected to GND and must be soldered to a large-area ground plane for thermal performance and AOI compatibility.