Texas Instruments TPS3305-33DGNG4

Overview

TPS3305-33DGNG4 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 8-pin HVSSOP package for embedded power sequencing.

For engineers reviewing the TPS3305-33DGNG4 datasheet, TPS3305-33DGNG4 pinout, TPS3305-33DGNG4 application, or TPS3305-33DGNG4 equivalent, key selection criteria include dual-rail threshold accuracy (4.55 V / 2.93 V typ), temperature-compensated reference, MR/WDI control flexibility, and operation across –40°C to +85°C.

Technical Context

The TPS3305-33DGNG4 integrates two independent voltage monitors with hysteresis (30–40 mV), a 1.25 V internal reference, and a watchdog timer with 1.6 s timeout. Its logic combines SENSEn undervoltage detection, manual reset (MR), and WDI edge-triggering to assert RESET when any monitored rail falls below its threshold or WDI stalls.

RESET assertion is synchronized to a fixed 200 ms delay after all conditions recover; no external capacitor is required. The device supports VDD operation from 2.7 V to 6 V and guarantees defined RESET output down to VDD ≥ 1.1 V, enabling robust initialization in brownout scenarios.

Key Specifications

Pinout & Package

HVSSOP-8 (DGN) package: 3.0 mm × 3.0 mm, 0.65 mm pitch, 1.1 mm max height, exposed thermal pad (PowerPAD™) for enhanced thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3305-33DGNG4, the SOIC variant trades space efficiency for easier hand-soldering and thermal margin, while TPS3808G33 sacrifices dual monitoring to achieve sub-µA quiescent current-making it unsuitable as a drop-in replacement but viable for simplified 3.3 V-only designs.

Availability

TPS3305-33DGNG4 is available at Aetrix Electronics and suitable for industrial PLCs, automotive body controllers, DSP-based test equipment, and battery-powered instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for TPS3305-33DGNG4 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 specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in industrial, automotive, and communications markets.

The TPS3305 family was designed specifically for dual-rail power supervision in DSP and microprocessor systems, addressing the need for accurate, low-power, and integrated reset generation with watchdog safety.

FAQ

What is the function of the two RESET pins on the TPS3305-33DGNG4?

The TPS3305-33DGNG4 provides both active-low (Pin 5) and active-high (Pin 6) RESET outputs to interface flexibly with diverse host logic families. The active-low output is open-drain for wired-OR capability, while the active-high output is push-pull for direct connection to CMOS inputs. Both reflect identical reset state timing and are asserted simultaneously during any fault condition-SENSE undervoltage, WDI timeout, or MR activation.

Does the TPS3305-33DGNG4 require external components to set its reset delay?

No, the TPS3305-33DGNG4 uses an internal factory-programmed timer to deliver a fixed 200 ms reset delay after all monitored voltages and inputs return to valid states. This eliminates the need for external RC networks, reducing component count, PCB area, and timing variability due to capacitor tolerance or temperature drift-critical for repeatable power-on behavior in production systems.

What are the exact threshold voltages monitored by the TPS3305-33DGNG4?

The TPS3305-33DGNG4 monitors SENSE1 at a typical threshold of 4.55 V (min 4.46 V, max 4.64 V) and SENSE2 at a typical threshold of 2.93 V (min 2.86 V, max 3.00 V), both specified over –40°C to +85°C. These thresholds correspond to 5.0 V and 3.3 V nominal supplies, providing ~10% undervoltage margin for reliable detection of rail collapse or brownout events.

Can the TPS3305-33DGNG4 operate with a 2.7 V supply voltage?

Yes, the TPS3305-33DGNG4 operates across a VDD range of 2.7 V to 6 V and guarantees defined RESET output behavior down to VDD ≥ 1.1 V. At 2.7 V, it maintains full functionality-including accurate SENSE threshold detection, watchdog timing, and MR response-enabling use in wide-input auxiliary supplies or legacy 3 V systems where headroom is constrained.

How does the watchdog timer in the TPS3305-33DGNG4 respond to WDI signal transitions?

The watchdog timer in the TPS3305-33DGNG4 triggers on edges (rising or falling) of the WDI input. If no transition occurs within 1.6 s (typical timeout), RESET is asserted. The timer resets on each valid edge, allowing firmware to maintain supervision by toggling WDI periodically-typically every 500–800 ms-to prevent false resets while detecting true software hangs or execution stalls.