Texas Instruments TPS3306-18DGKG4

Overview

TPS3306-18DGKG4 from Texas Instruments is a dual-voltage supervisory IC designed for DSP and processor-based systems requiring independent monitoring of 3.3 V and 1.8 V rails. It integrates power-on reset (100 ms delay), watchdog timer (0.8 s timeout), open-drain RESET and PFO outputs, and a dedicated power-fail comparator. It operates across –40°C to +85°C in the 8-pin VSSOP package and is used in embedded control systems and portable battery-powered equipment.

For engineers reviewing the TPS3306-18DGKG4 datasheet, TPS3306-18DGKG4 pinout, TPS3306-18DGKG4 application, or TPS3306-18DGKG4 equivalent, key selection considerations include its dual-threshold sensing (2.93 V / 1.68 V), low 15 µA supply current, defined RESET assertion down to VDD ≥ 1.1 V, and compatibility with microprocessor/DSP initialization sequences requiring precise voltage supervision and fail-safe recovery.

Technical Context

The TPS3306-18DGKG4 implements two independent voltage comparators with fixed thresholds (2.93 V on SENSE1, 1.68 V on SENSE2) referenced to an internal 1.25 V bandgap, each with ~15 mV hysteresis. Its RESET output is asserted low when either sensed voltage falls below its threshold or during power-up until VDD exceeds 1.1 V and both SENSE inputs stabilize above their thresholds for 100 ms.

The integrated watchdog circuit triggers on any WDI edge (low-to-high or high-to-low) and resets after 0.8 s if untriggered; leaving WDI floating disables it. The PFI/PFO path provides a separate 1.25 V reference comparator for external voltage monitoring, supporting configurable trip points via resistor dividers.

Key Specifications

Pinout & Package

VSSOP-8 (DGK) package: 3.0 mm × 3.0 mm, 1.1 mm max height, exposed pad optional, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3306-18DR and MAX6326–18, the TPS3306-18DGKG4 uniquely delivers compact dual-rail supervision with integrated watchdog and power-fail warning in one VSSOP-8 device - essential for space-limited, multi-voltage DSP platforms where coordination between rails and fail-safe recovery are non-negotiable.

Availability

TPS3306-18DGKG4 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, automotive infotainment head units, and network edge gateways requiring stable component supply and long-term production continuity.

Supply support for TPS3306-18DGKG4 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, precision, and energy efficiency.

The TPS3306 family was engineered specifically for dual-voltage DSP and processor initialization, addressing the need for coordinated, low-power, and temperature-stable supervision of multiple supply rails in real-time embedded systems.

FAQ

What is the exact SENSE1 and SENSE2 threshold voltage for TPS3306-18DGKG4?

The TPS3306-18DGKG4 has a typical SENSE1 threshold of 2.93 V and a typical SENSE2 threshold of 1.68 V, both measured at TA = 25°C and specified over –40°C to +85°C with ±3% tolerance. These thresholds are factory-trimmed and apply directly to monitoring 3.3 V and 1.8 V rails respectively, with ~15 mV hysteresis to prevent chatter near trip points. The TPS3306-18DGKG4 datasheet Table 1 confirms these values as nominal for the -18 variant.

Does TPS3306-18DGKG4 require external components to operate?

The TPS3306-18DGKG4 requires no external timing components for its core functions: RESET delay (100 ms) and watchdog timeout (0.8 s) are fully internal. A 0.1 µF ceramic bypass capacitor is recommended between VDD and GND per TI guidelines. External resistors are optional - only needed if using PFI for custom voltage monitoring. The TPS3306-18DGKG4 operates stand-alone for basic dual-rail supervision.

Can TPS3306-18DGKG4 supervise 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, the PFI input accepts any voltage above 1.25 V via an external resistor divider, enabling supervision of auxiliary rails (e.g., 5 V, 2.5 V, or battery voltage). SENSE1/SENSE2 thresholds are fixed and not adjustable; only PFI offers configurable monitoring. The TPS3306-18DGKG4 specification explicitly supports this PFI flexibility in the "Power-Fail Comparator" section.

What is the function of the WDI pin on TPS3306-18DGKG4?

The WDI (Watchdog Input) pin on TPS3306-18DGKG4 is an edge-sensitive input that resets the internal 0.8 s watchdog timer on any transition (low-to-high or high-to-low). If untriggered for >0.8 s, it forces RESET low. Leaving WDI floating disables the watchdog. The TPS3306-18DGKG4 datasheet specifies WDI timing parameters including pulse width (100 ns min) and input current limits, confirming its role as a hardware safety mechanism for firmware liveliness.

Is TPS3306-18DGKG4 pin-compatible with other TPS3306 variants?

Yes - all TPS3306-xxDGK variants (including TPS3306-15DGK, TPS3306-18DGK, TPS3306-20DGK, etc.) share identical VSSOP-8 pinout, electrical interface, and package dimensions. The only differences are factory-programmed SENSE1/SENSE2 thresholds. The TPS3306-18DGKG4 can be substituted for other DGK-packaged variants on the same PCB footprint, provided the voltage monitoring requirements match its 2.93 V / 1.68 V thresholds.