Texas Instruments UCC2946DTR

Overview

UCC2946DTR from Texas Instruments is a microprocessor supervisor IC with integrated watchdog timer, programmable reset threshold (1.235 V ±2%), programmable reset period (140–320 ms), and programmable watchdog period (0.96–2.56 s). It operates from 2.1 V to 5.5 V, draws ≤18 µA supply current, and asserts valid reset down to VDD = 1 V - used in industrial embedded systems requiring reliable power-on and fault recovery.

For engineers reviewing the UCC2946DTR datasheet, UCC2946DTR pinout, UCC2946DTR application, or UCC2946DTR equivalent, key selection criteria include its –40°C to +95°C operating temperature range, 8-pin TSSOP (PW) package, dual-programmable timing architecture, and independent RES/WDO outputs for flexible system-level reset coordination.

Technical Context

The UCC2946DTR implements two independent precision timing blocks: a reset circuit triggered by voltage monitoring at RTH (comparing against 1.235 V internal reference) and a watchdog circuit driven by edge detection on WDI. Reset assertion is filtered against VDD glitches using hysteresis (15 mV) and overdrive-delay response per Figure 1.

Both reset period (TRP = 3.125 × CRP) and watchdog period (TWP = 25 × CWP) are set via external capacitors charged by 400 nA current sources. The IC maintains functional reset validity down to 1 V VDD and supports manual reset via RTH shunt switch.

Key Specifications

Pinout & Package

UCC2946DTR is housed in an 8-pin TSSOP (PW) package - thin, surface-mount, 3.0 mm × 4.4 mm footprint with 0.65 mm pitch - optimized for space-constrained industrial PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33DBVR and MAX6816EUT+T, the UCC2946DTR uniquely delivers fully independent, capacitor-programmable reset and watchdog timing in one device - essential for systems requiring both power-rail integrity and runtime firmware health monitoring without external logic.

Availability

UCC2946DTR is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and telecom infrastructure requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for UCC2946DTR 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The UCC2946DTR belongs to TI's legacy microprocessor supervisor family - designed specifically for robust, programmable power-monitoring and fault-recovery in harsh-environment embedded systems.

FAQ

What is the operating temperature range for UCC2946DTR?

The UCC2946DTR is rated for –40°C to +95°C junction temperature, making it suitable for extended-temperature industrial applications such as factory automation controllers and outdoor telecom equipment. This range exceeds the commercial-grade UCC3946 (0°C to +70°C) and sits between the military-grade UCC1946 (–55°C to +125°C) and commercial variant. Its qualification ensures stable reset threshold and timing performance across the full span.

Can UCC2946DTR monitor voltages other than VDD?

Yes - the UCC2946DTR monitors voltage at the RTH pin, not VDD directly. By connecting a resistor divider from the target rail (e.g., 5 V, 12 V, or isolated auxiliary supply) to RTH, users can program any reset threshold using V_RESET = 1.235 V × (R1 + R2)/R2. This flexibility allows supervision of multiple rails with a single device and supports manual reset via a switch across R2 - a capability confirmed in the SLUS247B datasheet application diagrams.

How does the UCC2946DTR handle supply voltage glitches?

The UCC2946DTR rejects short-duration VDD transients using built-in glitch filtering: only dips exceeding 100 mV in amplitude and lasting longer than ~120 µs (per Figure 1) will trigger RES assertion. This behavior stems from internal overdrive-delay circuitry tied to the RTH comparator, ensuring immunity to switching noise or coupling spikes. Glitches below this threshold are ignored - preventing false resets during normal operation of adjacent high-speed circuits.

What capacitor types are recommended for RP and WP on UCC2946DTR?

NPO/C0G ceramic capacitors are explicitly recommended for both RP and WP pins due to their low leakage, tight tolerance, and minimal voltage/temperature drift. The UCC2946DTR uses 400 nA precision current sources to charge these caps; high-leakage dielectrics (e.g., X7R, Y5V) introduce timing errors and reduce watchdog/reset period accuracy. Typical values are 64 nF for nominal 200 ms reset and 1.6 s watchdog periods - values validated in the SLUS247B electrical characteristics table.

Is UCC2946DTR pin-compatible with UCC3946 or UCC1946?

Yes - UCC2946DTR shares identical pinout, package options (SOIC-8, TSSOP-8, DIP-8), and functional block diagram with UCC1946 and UCC3946. All three variants use the same connection diagram (SLUS247B, page 3) and pin descriptions. Differences lie solely in temperature rating and minor electrical specs (e.g., UCC2946 min VDD = 2.1 V vs. UCC3946's 2.0 V); no PCB layout change is needed when substituting within the same package type.