Texas Instruments TPS3305-33DG4

Overview

TPS3305-33DG4 from Texas Instruments is a dual-voltage supervisor IC for DSP and processor-based systems, monitoring 5.0 V (SENSE1) and 3.3 V (SENSE2) rails with factory-programmed 200 ms reset delay, watchdog timeout of 1.6 s (typ), and supply current of 40 µA. It delivers active-low and active-high RESET outputs in an SOIC-8 package for embedded power sequencing in industrial and portable equipment.

For engineers reviewing the TPS3305-33DG4 datasheet, TPS3305-33DG4 pinout, TPS3305-33DG4 application, or TPS3305-33DG4 equivalent, this page provides verified specifications, terminal functions, dual-rail supervision behavior, watchdog timing, and validated alternative parts for system-level reset architecture design.

Technical Context

The TPS3305-33DG4 implements two independent voltage monitoring channels with temperature-compensated 1.25 V reference, hysteresis (30–40 mV), and threshold accuracy over –40°C to +85°C. Each SENSE input asserts RESET when falling below its nominal threshold (4.55 V for SENSE1, 2.93 V for SENSE2).

Its integrated watchdog timer triggers RESET if WDI remains static beyond 1.6 s (typ); MR provides manual reset override with 0.3×VDD/0.7×VDD logic thresholds. RESET deassertion requires both SENSE inputs above threshold plus 200 ms delay.

Key Specifications

Pinout & Package

TPS3305-33DG4 is housed in an SOIC-8 (D) package, 3.9 mm × 4.9 mm, 1.75 mm max height, RoHS-compliant with NIPDAU lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-supply supervision applications.

Compared with TPS3305-33DG4, TPS3305-33DR offers identical supervision performance in tape-and-reel format for production lines, while MAX6816EUT+T provides a smaller, lower-cost alternative for single-rail applications where dual monitoring and watchdog are unnecessary.

Availability

TPS3305-33DG4 is available at Aetrix Electronics and suitable for industrial PLC control, portable medical devices, automotive infotainment head units, and notebook embedded controller applications requiring stable component supply and long-term lifecycle support.

Supply support for TPS3305-33DG4 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 reliability, precision, and energy efficiency.

The TPS3305 family was designed specifically for dual-rail power supervision in DSP and microprocessor systems, addressing the need for coordinated reset sequencing across core and I/O voltage domains.

FAQ

What is the exact reset threshold voltage for SENSE1 on the TPS3305-33DG4?

The TPS3305-33DG4 has a nominal SENSE1 threshold of 4.55 V (typ), with a guaranteed range of 4.46 V to 4.67 V over –40°C to +85°C. This threshold monitors a 5.0 V supply rail and includes 40 mV hysteresis to prevent chatter near the trip point. The value is factory-trimmed and does not require external calibration. TPS3305-33DG4 maintains this specification across its full operating voltage and temperature range.

Does the TPS3305-33DG4 require an external capacitor for reset delay timing?

No, the TPS3305-33DG4 uses a factory-programmed 200 ms (typ) reset delay with no external capacitor required. This internal timing eliminates component count, board area, and tolerance-related variation in power-up sequencing. The delay begins after both SENSE1 and SENSE2 rise above their respective thresholds and is fully specified from –40°C to +85°C. TPS3305-33DG4 achieves this via on-chip oscillator and counter circuitry.

Can the TPS3305-33DG4 supervise voltages other than 5.0 V and 3.3 V?

The TPS3305-33DG4 is specifically trimmed for 5.0 V (SENSE1) and 3.3 V (SENSE2) rails, with thresholds of 4.55 V and 2.93 V (typ), respectively. While it operates from VDD = 2.7–6.0 V, its internal comparator thresholds are fixed per variant and not adjustable. For other voltage combinations, TI offers TPS3305-18 (3.3 V / 1.8 V) and TPS3305-25 (3.3 V / 2.5 V). TPS3305-33DG4 must be used only with its designated rail voltages to ensure correct supervision behavior.

What is the watchdog timeout period for the TPS3305-33DG4, and how is it triggered?

The TPS3305-33DG4 watchdog timeout is 1.6 s (typ), with a range of 1.1 s to 2.3 s over temperature. It is triggered when the WDI pin remains static (no rising or falling edge) for longer than this interval. The timer resets on each WDI transition; failure to toggle within the window forces RESET assertion regardless of SENSE input states. TPS3305-33DG4 implements this function with an internal oscillator and logic, requiring no external components.

Is the TPS3305-33DG4 pin-compatible with other members of the TPS3305 family?

Yes, all TPS3305-x variants-including TPS3305-18, TPS3305-25, and TPS3305-33-share identical SOIC-8 (D) and HVSSOP-8 (DGN) pinouts and electrical interfaces. The only differences are factory-trimmed SENSE thresholds and part marking. This allows direct substitution in the same PCB footprint when changing supervised voltage combinations, provided the new thresholds match system requirements. TPS3305-33DG4 maintains full pin and functional compatibility across the family.