Texas Instruments TPS3305-18DR

Overview

TPS3305-18DR from Texas Instruments is a dual-voltage supervisor IC designed for DSP- and processor-based systems requiring independent monitoring of core (1.8 V) and I/O (3.3 V) supply rails. It features fixed 200 ms power-on reset delay, 1.6 s watchdog timeout, ±40 µA supply current, and operates from 2.7 V to 6 V over –40°C to +85°C - enabling reliable system initialization in portable and industrial embedded applications.

For engineers reviewing the TPS3305-18DR datasheet, TPS3305-18DR pinout, TPS3305-18DR application, or TPS3305-18DR equivalent, key selection criteria include dual-threshold sensing (1.68 V / 2.93 V), active-low and active-high RESET outputs, MR/WDI control interface, SOIC-8 packaging, and micropower operation critical for battery-powered and thermally constrained designs.

Technical Context

The TPS3305-18DR implements two independent voltage sense comparators with temperature-compensated 1.25 V reference, each feeding into a shared reset logic block with factory-programmed 200 ms delay. Its watchdog timer monitors WDI toggling with 1.6 s timeout, asserting RESET if no edge occurs - supporting fail-safe recovery in real-time processors.

RESET assertion occurs on any of three conditions: SENSE1 < 1.68 V, SENSE2 < 2.93 V, or WDI stall > 1.6 s. Manual reset (MR) provides asynchronous override, while dual RESET outputs (active-low and active-high) simplify interface to diverse host logic families without external inverters.

Key Specifications

Pinout & Package

TPS3305-18DR 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 supervision applications.

Compared with TPS3305-18DR, the TPS3305-18DGNR offers identical functionality in a smaller HVSSOP package ideal for compact layouts, while the TPS3808G33DBVR provides simpler single-rail supervision but cannot replace dual-monitoring requirements without redesign.

Availability

TPS3305-18DR is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive infotainment modules, and portable DSP-based equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TPS3305-18DR 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 and embedded processing solutions, with over 90 years of innovation in power management, signal chain, and microcontrollers.

The TPS3305 family was engineered specifically for dual-rail DSP and microprocessor systems, addressing the need for coordinated, low-power, and fault-tolerant power sequencing and runtime supervision.

FAQ

What is the exact threshold voltage for SENSE1 on the TPS3305-18DR?

The TPS3305-18DR has a nominal SENSE1 threshold of 1.68 V (VIT−) at TA = 0°C to +85°C, with min/max of 1.64 V / 1.72 V. This is factory-trimmed to supervise a 1.8 V supply rail, providing 6% hysteresis margin to prevent chatter near the trip point. The threshold remains stable across temperature due to an integrated temperature-compensated voltage reference.

Does the TPS3305-18DR require an external capacitor for its reset delay function?

No, the TPS3305-18DR uses an internal oscillator and counter to generate its 200 ms power-on reset delay - no external capacitor is needed. This simplifies design, improves timing accuracy versus RC-based solutions, and eliminates capacitor aging or temperature drift effects. The delay is factory-programmed and specified from 140 ms (min) to 280 ms (max) over temperature.

Can the TPS3305-18DR monitor voltages other than 1.8 V and 3.3 V?

The TPS3305-18DR is specifically trimmed for 1.8 V (SENSE1) and 3.3 V (SENSE2) nominal rails, with fixed thresholds of 1.68 V and 2.93 V respectively. While it will respond to any voltage applied to those pins, accurate supervision requires matching the device variant to the target rail - e.g., TPS3305-25DR for 2.5 V/3.3 V systems. Using mismatched variants risks premature or missed reset assertion.

What is the purpose of having both RESET and RESET pins on the TPS3305-18DR?

The TPS3305-18DR provides complementary reset outputs: RESET (Pin 5) is active-low open-drain, and RESET (Pin 6) is active-high push-pull. This allows direct interface to MCUs requiring either polarity without external logic. The open-drain output supports wired-OR configurations and level shifting, while the push-pull output eliminates external pull-up resistors and reduces power consumption in active-high reset architectures.

Is the TPS3305-18DR suitable for automotive applications?

Yes, the TPS3305-18DR is rated for –40°C to +85°C operation and manufactured in TI's qualified automotive-grade process flow. It meets key automotive reliability requirements including robust ESD protection (per JEDEC JS-001), stable threshold performance over temperature, and MSL Level-1 handling. While not AEC-Q200 certified out-of-box, it is widely deployed in automotive infotainment and body control modules where extended temperature and long-term stability are critical - TPS3305-18DR design-in documentation supports qualification per customer-specific requirements.