Texas Instruments TPS3306-18QDRG4Q1

Overview

TPS3306-18QDRG4Q1 from Texas Instruments is an automotive-grade dual supervisory circuit designed for DSP and processor-based systems requiring independent monitoring of 3.3 V and 1.8 V supply rails. It integrates power-on reset (100-ms delay), watchdog timer (0.8-s timeout), open-drain RESET and PFO outputs, and operates across −40°C to 125°C with 15 µA typical supply current.

For engineers reviewing the TPS3306-18QDRG4Q1 datasheet, TPS3306-18QDRG4Q1 pinout, TPS3306-18QDRG4Q1 application, or TPS3306-18QDRG4Q1 equivalent, this device delivers verified dual-voltage supervision, fail-safe watchdog timing, and automotive-qualified thermal robustness in an SOIC-8 package - critical for multivoltage embedded control and intelligent instrumentation designs.

Technical Context

The TPS3306-18QDRG4Q1 implements two independent voltage comparators with fixed thresholds: SENSE1 monitors 3.3 V nominal at 2.93 V (typ), SENSE2 monitors 1.8 V nominal at 1.68 V (typ), each with 15 mV hysteresis. Its internal 100-ms reset delay timer activates only after both sense inputs exceed their respective thresholds.

A dedicated watchdog circuit responds to WDI transitions with a 0.8-s timeout (typ), asserting RESET if untriggered; the PFI comparator references 1.25 V internally and supports external resistor networks for custom power-fail detection. All outputs are open-drain, enabling wired-OR configurations and flexible pull-up voltage selection.

Key Specifications

Pinout & Package

TPS3306-18QDRG4Q1 is housed in an 8-pin SOIC (D) package with standard 1.27 mm pitch, 3.9 mm body width, and 1.75 mm max height - compatible with automated PCB assembly and IPC-7351 land patterns.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3306-18QDRG4Q1, the active TPS3306-18QDRQ1 offers identical performance with assured long-term supply, while TLV809E29DBVR reduces footprint and quiescent current but sacrifices dual-rail autonomy, watchdog safety, and automotive qualification - making it unsuitable for safety-critical or multivoltage systems.

Availability

TPS3306-18QDRG4Q1 is available at Aetrix Electronics and suitable for automotive engine control units, industrial motion controllers, portable medical instruments, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for TPS3306-18QDRG4Q1 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 automotive ICs, with decades of experience in high-reliability power management and system supervision solutions.

The TPS3306-Q1 family was engineered specifically for automotive and industrial systems demanding concurrent monitoring of multiple voltage domains, combining reset generation, watchdog safety, and power-fail warning in a single AEC-Q100-qualified package.

FAQ

What is the exact SENSE2 threshold voltage for TPS3306-18QDRG4Q1?

The TPS3306-18QDRG4Q1 has a nominal SENSE2 threshold of 1.68 V, specified as 1.62 V (min) to 1.74 V (max) over −40°C to 125°C. This value is factory-trimmed to supervise 1.8 V nominal supplies with 15 mV hysteresis, ensuring stable release during brownout recovery without oscillation. The threshold remains stable across supply voltage (2.7–6 V) and temperature.

Does TPS3306-18QDRG4Q1 support watchdog functionality, and how is it configured?

Yes, TPS3306-18QDRG4Q1 integrates a watchdog timer with a 0.8-s timeout (typ). It is configured via the WDI pin (Pin 7): either a rising or falling edge resets the internal timer. If no transition occurs within the timeout window, RESET is asserted for the full 100-ms delay period. Leaving WDI unconnected disables the watchdog entirely - no external pull-up or pull-down is required.

Can TPS3306-18QDRG4Q1 monitor voltages other than 3.3 V and 1.8 V?

Yes - while SENSE1 and SENSE2 are optimized for 3.3 V and 1.8 V rails respectively, the PFI input (Pin 3) accepts any external voltage above 1.25 V via a resistor divider. With 1% precision resistors and ~1 MΩ total resistance, PFI can supervise auxiliary supplies (e.g., 5 V, 12 V, or battery voltage) for low-battery warnings or secondary power-fail detection independent of the main reset logic.

What is the minimum VDD required for TPS3306-18QDRG4Q1 to assert RESET?

TPS3306-18QDRG4Q1 defines RESET output functionality down to VDD ≥ 1.1 V. Below this level, RESET behavior is undefined. At VDD = 1.1 V, the internal reference and comparators remain operational enough to detect SENSEn or WDI faults and assert RESET - enabling early-fail detection during power ramp-up or brownout conditions before full logic-level operation is possible.

Is TPS3306-18QDRG4Q1 pin-compatible with other devices in the TPS3306-Q1 family?

Yes - all TPS3306-Q1 variants (e.g., TPS3306-15QDRQ1, TPS3306-25QDRQ1) share identical SOIC-8 (D) packaging and pinout. The only differences are factory-trimmed SENSE1/SENSE2 thresholds and part marking (e.g., "618Q1" for TPS3306-18QDRG4Q1). No PCB layout changes are needed when substituting between members of the family for different voltage combinations.