Texas Instruments TPS3850H33DRCT

Overview

TPS3850H33DRCT from Texas Instruments is a precision voltage supervisor IC with integrated programmable window watchdog timer, designed for high-reliability power-rail monitoring in microcontroller and SoC systems. It delivers 0.8% threshold accuracy over –40°C to +125°C, supports 1.6 V–6.5 V supply range, features open-drain RESET and WDO outputs, and enables ±4% or ±7% fault windows on rails from 0.9 V to 5.0 V - used in ultrasound scanners and active antenna systems.

For engineers reviewing the TPS3850H33DRCT datasheet, TPS3850H33DRCT pinout, TPS3850H33DRCT application, or TPS3850H33DRCT equivalent, key selection criteria include its factory-programmed vs capacitor-programmable reset/watchdog timing, dual-threshold hysteresis (0.5%), SENSE pin idle current (2.5 µA), and VSON-10 thermal-pad package compatibility with tight-layout industrial designs.

Technical Context

The TPS3850H33DRCT implements a dual-comparator window architecture on the SENSE pin with independent overvoltage (VIT+(OV)) and undervoltage (VIT−(UV)) thresholds, each achieving ±0.8% accuracy across temperature. Its internal precision clock drives both the RESET delay timer (tRST) and window watchdog boundaries (tWDL/tWDU), with timing selectable via CRST/CWD pins or factory defaults.

Watchdog operation uses a ratio-based window (1:2, 1:4, 3:4) defined by SET0/SET1 logic states, where WDI edge timing must fall strictly between tWDL(max) and tWDU(min); WDO asserts only when RESET is high, ensuring coordinated fault signaling. The device operates with 10 µA typical supply current and supports glitch immunity up to 40 ps at full temperature range.

Key Specifications

Pinout & Package

VSON-10 (DRC) package with 3.00 mm × 3.00 mm body size and exposed thermal pad connected internally to GND. Requires solder paste stencil optimization for thermal pad reflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3850H33DRCT, TPS3851H33DRCT adds hardware watchdog disable capability while maintaining pin and timing compatibility, whereas MAX6373KA29+T offers lower-cost fixed-threshold supervision without window watchdog or programmable timing - making it suitable only for non-safety-critical, single-rail use cases.

Availability

TPS3850H33DRCT is available at Aetrix Electronics and suitable for ultrasound scanner power management, active antenna system monitoring, and robot servo drive control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TPS3850H33DRCT 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 solutions, with leadership in power management, signal chain, and high-reliability ICs.

The TPS3850 product line delivers precision voltage supervision with integrated window watchdog timers for mission-critical systems where deterministic fault detection and timing integrity are essential - targeting medical imaging, 5G infrastructure, and industrial automation.

FAQ

What is the voltage threshold accuracy of the TPS3850H33DRCT over temperature?

The TPS3850H33DRCT achieves ±0.8% overvoltage and undervoltage threshold accuracy across the full operating junction temperature range of –40°C to +125°C. This specification applies to both VIT+(OV) and VIT−(UV) thresholds on the SENSE pin and is validated per TI's production test flow using statistical process control on 41,111 units. The TPS3850H33DRCT maintains this accuracy without calibration, enabling robust power-rail monitoring in automotive under-hood and industrial control environments.

How does the watchdog window timing work on the TPS3850H33DRCT?

The TPS3850H33DRCT implements a true window watchdog where the WDI falling edge must occur strictly between tWDL (lower boundary) and tWDU (upper boundary) to prevent WDO assertion. These boundaries are set independently via CWD pin configuration (capacitor or resistor) and SET0/SET1 logic states, supporting ratios of 1:2, 1:4, or 3:4. For example, with CWD = NC and SET0 = 0/SET1 = 1, tWDL = 1.48–2.22 ms and tWDU = 23.4–31.6 ms. The TPS3850H33DRCT enforces this window with 50 ns timing resolution and ignores WDI when RESET is low.

Can the TPS3850H33DRCT monitor voltages below 1.0 V?

No, the TPS3850H33DRCT is not specified to monitor rails below 0.9 V. Its SENSE pin supports common rails from 0.9 V to 5.0 V, with factory-programmed thresholds including 0.9 V, 1.2 V, 1.8 V, 3.0 V, 3.3 V, and 5.0 V options. The device's internal reference and comparator architecture require minimum headroom for accurate 0.8% threshold tracking; attempting to supervise sub-0.9 V rails (e.g., 0.8 V core supplies) will result in undefined behavior and loss of accuracy. For such rails, TI recommends the TPS3852 series with 0.4 V adjustable threshold.

What is the purpose of the thermal pad on the TPS3850H33DRCT VSON-10 package?

The exposed thermal pad on the TPS3850H33DRCT VSON-10 (DRC) package is internally connected to GND and serves two critical functions: (1) it provides a low-thermal-resistance path (RθJB = 26.1°C/W) from die to PCB ground plane, enabling reliable operation at +125°C junction temperature; and (2) it improves electrical stability by reducing ground impedance for the internal comparators and timing circuitry. TI specifies that the pad must be soldered to a large-area copper pour using appropriate stencil aperture and reflow profile - omitting this connection degrades thermal performance and may cause timing drift or false resets under sustained load.

Does the TPS3850H33DRCT support watchdog disable during development?

Yes, the TPS3850H33DRCT supports hardware watchdog disable via SET0 and SET1 pin configuration. When SET0 = 1 and SET1 = 0 (or SET0 = 1 and SET1 = 1 with CWD pulled up), the watchdog function is disabled and WDO remains high-impedance regardless of WDI activity. In this mode, WDI must be actively driven to VDD or GND - leaving it floating violates the absolute maximum rating and risks latch-up. This feature allows safe firmware development and debugging without unintended resets, and the TPS3850H33DRCT retains full supervisor functionality (RESET generation on OV/UV) during disable.