Texas Instruments TPS3305-33DGNRG4

Overview

TPS3305-33DGNRG4 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 provides active-low and active-high RESET outputs and operates across –40°C to +85°C in HVSSOP-8 package.

For engineers reviewing the TPS3305-33DGNRG4 datasheet, TPS3305-33DGNRG4 pinout, TPS3305-33DGNRG4 application, or TPS3305-33DGNRG4 equivalent, key selection criteria include dual-rail threshold accuracy (4.55 V / 2.93 V typ), watchdog input timing compliance, MR assertion behavior, and HVSSOP-8 thermal pad layout requirements.

Technical Context

The TPS3305-33DGNRG4 implements two independent voltage-sense comparators with temperature-compensated 1.25 V reference, hysteresis (40 mV at 4.55 V threshold), and internal power-on reset generator. Its watchdog timer asserts RESET if WDI remains static beyond 1.1–2.3 s, with propagation delays under 5 µs from SENSEn to RESET.

RESET assertion occurs when either SENSE1 falls below 4.46–4.67 V or SENSE2 falls below 2.86–3.02 V (over full temperature range), or when MR is pulled low. The device supports VDD as low as 1.1 V for defined RESET output state and tolerates supply voltages from 2.7 V to 6.0 V.

Key Specifications

Pinout & Package

HVSSOP-8 (DGN) package: 3.0 mm × 3.0 mm body, 0.65 mm pitch, 1.1 mm max height, with exposed thermal pad (Pin 9) for enhanced thermal performance. RoHS-compliant, NIPDAU lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3305-33DGNRG4, TPS3305-33DGN offers identical supervision functionality but lacks the G4 environmental designation, while TPS3808G33DBVR reduces system complexity only when dual-rail and watchdog features are unnecessary - neither provides drop-in replacement capability without circuit redesign.

Availability

TPS3305-33DGNRG4 is available at Aetrix Electronics and suitable for industrial control units, automotive infotainment modules, and DSP-based signal processing equipment requiring stable component supply across extended temperature ranges.

Supply support for TPS3305-33DGNRG4 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, embedded processing, and connectivity technologies, with leadership in power management and precision analog ICs.

The TPS3305 family is designed specifically for dual-rail power supervision in DSP and microprocessor systems, addressing the need for coordinated reset sequencing, watchdog safety, and low-quiescent-current operation in space-constrained industrial and automotive applications.

FAQ

What is the exact reset threshold voltage for SENSE1 on the TPS3305-33DGNRG4?

The TPS3305-33DGNRG4 has a nominal SENSE1 threshold voltage of 4.55 V, with a guaranteed range of 4.46 V to 4.67 V over the full operating temperature range (–40°C to +85°C). This threshold applies specifically to the -33 variant and is factory-trimmed; it is not user-adjustable. The device uses an internal temperature-compensated 1.25 V reference to maintain stability across voltage and temperature variations. Hysteresis of 40 mV ensures noise immunity during rail recovery.

Does the TPS3305-33DGNRG4 support both active-high and active-low reset outputs simultaneously?

Yes, the TPS3305-33DGNRG4 provides two independent RESET outputs: Pin 5 is an active-low open-drain output requiring an external pull-up resistor, and Pin 6 is an active-high push-pull output capable of driving logic directly. Both outputs assert synchronously when any fault condition occurs - including SENSE1/SENSE2 undervoltage, WDI timeout, or MR assertion - and deassert only after both monitored rails remain above threshold for the full 200 ms delay period. This dual-output architecture simplifies integration with mixed-logic-system designs.

What is the watchdog timeout window for the TPS3305-33DGNRG4, and how is it triggered?

Watchdog timeout for the TPS3305-33DGNRG4 is specified as 1.1 s (min), 1.6 s (typ), and 2.3 s (max) - measured from the last valid edge on the WDI pin. A valid edge is defined as a transition crossing the MR/WDI input threshold (0.3×VDD to 0.7×VDD) with slew rate ≥50 ns/V. If no such edge occurs within the timeout window, RESET is asserted. The timeout is disabled when MR is held low. This behavior is implemented entirely within the TPS3305-33DGNRG4 and requires no external timing components.

Can the TPS3305-33DGNRG4 operate with a supply voltage lower than 2.7 V?

No, the absolute minimum recommended VDD for continuous operation of the TPS3305-33DGNRG4 is 2.7 V. However, the device guarantees defined RESET output behavior down to VDD = 1.1 V - meaning that if VDD drops below 2.7 V but remains ≥1.1 V, the RESET outputs will still respond correctly to SENSEn faults and MR assertion. Below 1.1 V, RESET state is undefined. The 2.7–6.0 V operating range ensures compatibility with common logic supplies while maintaining accurate threshold referencing via the internal bandgap.

Is the exposed thermal pad (Pin 9) on the TPS3305-33DGNRG4 HVSSOP package required to be soldered to ground?

Yes, the exposed thermal pad (Pin 9) on the TPS3305-33DGNRG4 HVSSOP-8 package must be electrically and thermally connected to PCB ground plane using multiple vias. TI's layout guidelines specify solder mask-defined pads, 100% solder paste coverage on the pad, and ≥4 thermal vias (0.3 mm diameter, filled/plugged) connecting to inner ground layers. Failure to properly connect the pad risks exceeding junction temperature limits under sustained load, potentially causing parametric shift or long-term reliability degradation - especially critical given the device's 1.1 mm profile and power dissipation characteristics in industrial environments.