Texas Instruments TPS3306-18DGKRG4

Overview

TPS3306-18DGKRG4 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 (DGK) package and is used in embedded control systems and portable battery-powered equipment.

For engineers reviewing the TPS3306-18DGKRG4 datasheet, TPS3306-18DGKRG4 pinout, TPS3306-18DGKRG4 application, or TPS3306-18DGKRG4 equivalent, key selection criteria include dual-threshold voltage supervision (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 reset sequencing and power-fail warning circuits.

Technical Context

The TPS3306-18DGKRG4 implements two independent voltage comparators with fixed thresholds (2.93 V on SENSE1, 1.68 V on SENSE2), each with ~20 mV hysteresis. Its internal power-on reset generator asserts RESET until both sensed voltages exceed their respective thresholds and remain stable for 100 ms.

A separate PFI comparator referenced to 1.25 V enables external power-fail detection via resistor divider, while the integrated watchdog circuit resets on WDI transitions (low-to-high or high-to-low) within 0.8 s - disabling when WDI is left floating. All outputs (RESET, PFO) are open-drain and rated for 5 mA sink current.

Key Specifications

Pinout & Package

The TPS3306-18DGKRG4 is housed in an 8-pin VSSOP (DGK) package, 3.0 mm × 3.0 mm × 1.1 mm, with exposed thermal pad and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3306-18DGKRG4, the SOIC-packaged TPS3306-18DR trades compactness for ease of handling, while the TPS386000RGPT offers lower IQ but sacrifices integrated dual-rail supervision, watchdog, and power-fail features - making TPS3306-18DGKRG4 optimal for space-limited DSP/processor systems needing full-feature supervision in one chip.

Availability

TPS3306-18DGKRG4 is available at Aetrix Electronics and suitable for embedded control systems, portable medical instruments, and automotive infotainment modules requiring stable component supply, guaranteed long-term availability, and RoHS-compliant packaging.

Supply support for TPS3306-18DGKRG4 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 TPS3306 family was engineered specifically for dual-rail DSP and processor initialization, addressing the need for precise, low-power, and integrated supervision of core and I/O supply domains in high-density embedded systems.

FAQ

What is the exact reset threshold voltage for SENSE2 on the TPS3306-18DGKRG4?

The TPS3306-18DGKRG4 has a factory-trimmed SENSE2 threshold voltage of 1.68 V (typical), with a tolerance of ±30 mV over temperature (–40°C to +85°C). This value is specified in Table 1 of the SLVS290C datasheet and applies exclusively to the -18 variant, ensuring accurate supervision of 1.8 V rails without external calibration.

Does the TPS3306-18DGKRG4 require external components to function as a basic power-on reset device?

No, the TPS3306-18DGKRG4 requires no external components for core reset functionality. With only VDD, GND, SENSE1, SENSE2, and RESET connected, it delivers a 100 ms active-low reset pulse after both monitored voltages exceed their thresholds. External resistors are needed only for PFI-based power-fail detection or if pull-up resistors are required on open-drain outputs.

Can the watchdog timer on the TPS3306-18DGKRG4 be disabled, and how?

Yes, the watchdog timer on the TPS3306-18DGKRG4 is disabled by leaving the WDI pin unconnected (high-impedance). The datasheet explicitly states that "leaving WDI unconnected disables the watchdog." No pull-up or pull-down is required - floating WDI is the defined disable condition, simplifying design when watchdog functionality is not needed.

What is the maximum sink current capability of the RESET output on the TPS3306-18DGKRG4?

The RESET output of the TPS3306-18DGKRG4 is an open-drain driver rated for a maximum sink current of 5 mA at VO ≤ 0.4 V (per Electrical Characteristics table, VDD = 3.3 V, IOL = 2 mA). This allows direct interfacing with standard CMOS inputs or driving small LEDs through appropriate current-limiting resistors without external buffers.

Is the TPS3306-18DGKRG4 pin-compatible with other members of the TPS3306 family, such as the TPS3306-25DGKR?

Yes, all TPS3306-x variants - including TPS3306-18DGKRG4 and TPS3306-25DGKR - share identical pinouts, package dimensions, and terminal functions across both DGK (VSSOP-8) and D (SOIC-8) packages. Only the internal voltage thresholds differ (e.g., 1.68 V vs. 2.25 V on SENSE2), enabling drop-in replacement when adjusting supervised rail voltages without layout changes.