Texas Instruments TPS3306-25D

Overview

TPS3306-25D from Texas Instruments is a dual-voltage supervisory IC designed for DSP and processor-based systems requiring independent monitoring of 3.3 V and 2.5 V rails. It integrates power-on reset with 100 ms delay, watchdog timer (0.8 s timeout), open-drain RESET and PFO outputs, and operates from –40°C to +85°C in SOIC-8 package.

For engineers reviewing the TPS3306-25D datasheet, TPS3306-25D pinout, TPS3306-25D application, or TPS3306-25D equivalent, this page delivers verified specifications, terminal functions, real-world use cases in embedded control and portable equipment, and validated alternative options for voltage supervision design.

Technical Context

The TPS3306-25D implements two independent voltage comparators with fixed thresholds: 2.93 V (SENSE1) for 3.3 V rail and 2.25 V (SENSE2) for 2.5 V rail, each with ~20 mV hysteresis. RESET asserts low when either SENSE input falls below its threshold or during power-up until VDD ≥1.1 V.

It includes a dedicated PFI comparator referenced to 1.25 V for external power-fail detection and a WDI-triggered watchdog with 0.8 s timeout. All outputs are open-drain, supporting wired-OR configurations and flexible pull-up voltage selection.

Key Specifications

Pinout & Package

TPS3306-25D is housed in an 8-pin SOIC (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 supervisory applications.

Compared with TPS3306-25DGK and TPS3823-25DBVR, the TPS3306-25D offers full dual-rail supervision plus watchdog and PFI in a standard SOIC-8, making it optimal for industrial and automotive-adjacent designs where layout flexibility and feature completeness are prioritized over minimal size.

Availability

TPS3306-25D is available at Aetrix Electronics and suitable for industrial embedded control, portable medical instrumentation, and automotive infotainment systems requiring stable component supply and long-term production continuity.

Supply support for TPS3306-25D 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 and system-level integration.

The TPS3306 family was engineered specifically for dual-voltage supervision in DSP and microprocessor systems, addressing the need for coordinated reset, power-fail warning, and watchdog functionality in compact, low-power packages.

FAQ

What is the exact SENSE2 threshold voltage for TPS3306-25D?

The TPS3306-25D has a typical SENSE2 threshold voltage of 2.25 V, with a guaranteed range of 2.20 V to 2.32 V across –40°C to +85°C. This threshold is factory-trimmed to supervise a nominal 2.5 V supply with ~10% undervoltage margin, and includes ~20 mV hysteresis to prevent chatter near the trip point. The TPS3306-25D datasheet specifies this value under Electrical Characteristics Table, condition VDD = 2.7 V to 6 V.

Can TPS3306-25D monitor voltages other than 3.3 V and 2.5 V?

Yes - while SENSE1 and SENSE2 are optimized for 3.3 V and 2.5 V rails respectively, the PFI input accepts any voltage above 1.25 V via an external resistor divider. For example, connecting a 1 MΩ total divider (R1 + R2) with 1% tolerance to a 5 V supply allows PFI to trigger at ~3.75 V. The TPS3306-25D's internal 1.25 V reference and 10 mV hysteresis ensure accurate, stable power-fail detection independent of the main supply rails.

Is the watchdog timer in TPS3306-25D enabled by default?

No - the watchdog timer in TPS3306-25D is disabled by default when WDI (Pin 7) is left unconnected or held at high impedance. To enable it, the host processor must drive WDI with periodic rising or falling edges within the 0.8 s timeout window. The TPS3306-25D datasheet explicitly states that leaving WDI unconnected disables the watchdog, making it safe for systems where lockup detection is not required.

What is the minimum VDD required for TPS3306-25D to assert RESET?

The TPS3306-25D asserts RESET when VDD rises above 1.1 V, per the "Power-up reset voltage" specification in the Electrical Characteristics table. This ensures early reset assertion during power ramp-up, even before SENSE inputs reach valid levels. The TPS3306-25D maintains RESET assertion until both SENSE1 > 2.93 V and SENSE2 > 2.25 V are satisfied and the 100 ms delay expires - a behavior confirmed in the Detailed Description section.

Does TPS3306-25D support operation at 2.7 V supply?

Yes - the TPS3306-25D is fully specified for operation from VDD = 2.7 V to 6 V, as stated in the Recommended Operating Conditions table. At 2.7 V, all key parameters remain valid: SENSE thresholds retain their typical values (2.93 V and 2.25 V), RESET delay remains 100 ms, and supply current stays at 15 µA typical. This makes the TPS3306-25D compatible with low-voltage systems such as battery-powered devices operating near end-of-life voltage.