Texas Instruments UCC2946TPWRQ1

Overview

UCC2946TPWRQ1 from Texas Instruments is an automotive-grade microprocessor supervisor IC with integrated watchdog timer, programmable reset threshold (1.235 V ±2%), reset period (140–320 ms), and watchdog period (0.96–2.56 s). It operates from 2.1 V to 5.5 V, asserts valid reset down to 1 V, and supports glitch-resistant supervision in engine control units and ADAS domain controllers.

For engineers reviewing the UCC2946TPWRQ1 datasheet, UCC2946TPWRQ1 pinout, UCC2946TPWRQ1 application, or UCC2946TPWRQ1 equivalent, key selection considerations include its programmable dual-timing architecture, automotive temperature range (–40°C to 105°C), TSSOP-8 package, and independent RES/WDO outputs for fault-isolated system recovery.

Technical Context

The UCC2946TPWRQ1 implements a precision voltage comparator with 1.235 V internal reference and external resistor divider (RTH pin) to set custom reset thresholds. Its reset assertion remains active for a capacitor-programmed duration (TRP = 3.125 × CRP) after VDD exceeds threshold.

A separate 8-bit counter driven by a 25× precision current source sets the watchdog timeout (TWP = 25 × CWP). WDI toggling resets the counter; failure triggers WDO low. Watchdog operation is disabled during active reset, preventing false timeouts during power-up sequences.

Key Specifications

Pinout & Package

UCC2946TPWRQ1 is housed in an 8-pin TSSOP (PW) package, 3.0 mm × 4.4 mm, 1.2 mm max height, RoHS-compliant with NIPDAU lead finish and MSL Level-2 rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervision applications.

Compared with TLV803E33DBVRQ1 and TPS3839G33DBVRQ1, the UCC2946TPWRQ1 uniquely supports fully independent, capacitor-programmable reset and watchdog periods-enabling precise alignment with custom processor boot times and firmware health-check intervals in complex automotive domains.

Availability

UCC2946TPWRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, body control modules, and infotainment head units requiring stable component supply across extended automotive temperature ranges and long production lifecycles.

Supply support for UCC2946TPWRQ1 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 delivering analog, embedded processing, and connectivity solutions with emphasis on automotive, industrial, and power management applications.

The UCC2946-Q1 belongs to TI's automotive supervisory IC product line, designed specifically to meet AEC-Q100 requirements for microprocessor reset and watchdog functions in harsh-temperature vehicle subsystems.

FAQ

What is the minimum supply voltage at which UCC2946TPWRQ1 asserts a valid reset signal?

The UCC2946TPWRQ1 asserts a valid reset signal (RES) down to VDD = 1.1 V, as specified in the Electrical Characteristics table. This ensures reliable reset generation during severe brown-out events such as automotive cold-crank, where battery voltage may dip below 2 V. The device maintains functional reset assertion even when VDD falls below the nominal operating range, making UCC2946TPWRQ1 suitable for safety-critical automotive power sequencing.

How is the reset threshold programmed on UCC2946TPWRQ1?

The reset threshold on UCC2946TPWRQ1 is programmed using an external resistor divider connected to the RTH pin (Pin 2), referenced to an internal 1.235 V bandgap. Equation 1 in the datasheet defines VRESET = 1.235 × (R1 + R2)/R2. High-value resistors (MΩ range) are recommended to minimize quiescent current. The UCC2946TPWRQ1 does not require trimming or calibration-threshold accuracy is maintained at ±2% across temperature and supply variations.

Can UCC2946TPWRQ1's watchdog and reset functions operate independently?

Yes, UCC2946TPWRQ1 provides fully independent reset and watchdog circuits with separate timing elements (RP and WP pins) and outputs (RES and WDO). The watchdog function is automatically disabled during active reset, preventing false timeouts during power-up. Each function can be configured with different capacitor values to match distinct system timing requirements-e.g., longer reset delay for slow-ramping supplies and shorter watchdog period for fast-failure detection in real-time firmware.

What package type and environmental rating does UCC2946TPWRQ1 use?

UCC2946TPWRQ1 uses an 8-pin TSSOP (PW) package, measuring 3.0 mm × 4.4 mm with 1.2 mm maximum height. It is RoHS-compliant with NIPDAU lead finish and rated MSL Level-2 (260°C, 1 year). The device is qualified per AEC-Q100 Grade 2 for operation from –40°C to 105°C ambient temperature, making it suitable for under-hood and chassis-mounted automotive applications where thermal and mechanical reliability are critical.

Does UCC2946TPWRQ1 support connecting WDO directly to RES for combined reset functionality?

Yes, UCC2946TPWRQ1 allows direct connection of WDO to RES, leveraging wired-OR behavior where the lower output dominates. When both outputs drive simultaneously, the low state prevails-ensuring reset is asserted if either condition occurs. However, this configuration increases current draw during fault states. For low-power or safety-critical designs, TI recommends using an external OR gate instead to avoid unintended current paths and maintain clean signal integrity in the UCC2946TPWRQ1 reset chain.