Texas Instruments TPS3306-20QDRQ1

Overview

TPS3306-20QDRQ1 from Texas Instruments is an automotive-grade dual supervisory circuit for DSP and processor-based systems, monitoring 3.3 V and 2.0 V supply rails with threshold voltages of 2.93 V (SENSE1) and 1.85 V (SENSE2), featuring integrated power-on reset (100 ms delay), watchdog timer (0.8 s timeout), open-drain RESET and PFO outputs, and operation from −40°C to 125°C.

For engineers reviewing the TPS3306-20QDRQ1 datasheet, TPS3306-20QDRQ1 pinout, TPS3306-20QDRQ1 application, or TPS3306-20QDRQ1 equivalent, key selection criteria include dual-voltage supervision accuracy, watchdog timing tolerance, automotive temperature compliance, and SO-8 package compatibility in multivoltage embedded control designs.

Technical Context

The TPS3306-20QDRQ1 implements two independent voltage comparators with fixed internal reference (1.25 V) and resistor-divider scaling to detect undervoltage on SENSE1 (3.3 V rail) and SENSE2 (2.0 V rail), with hysteresis of 20 mV per input. Its RESET logic asserts low when either sense input falls below its threshold and holds active for ≥100 ms after recovery.

A dedicated watchdog circuit monitors WDI transitions (low-to-high or high-to-low) with a nominal 0.8 s timeout; unconnected WDI disables this function. The PFI comparator provides programmable power-fail detection via external resistors, with PFO output active low when PFI drops below 1.25 V.

Key Specifications

Pinout & Package

TPS3306-20QDRQ1 is housed in an 8-pin SOIC (D) package, 3.91 mm × 4.90 mm footprint, 1.75 mm max height, RoHS-compliant with NIPDAU lead finish and MSL Level-2 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3306-20QDRQ1, the TPS3306-25QDRQ1 shifts SENSE2 threshold upward for 2.5 V compatibility but sacrifices 2.0 V core supervision accuracy, while the MAX6326 offers smaller footprint at the expense of losing dual-rail coordination and watchdog safety coverage.

Availability

TPS3306-20QDRQ1 is available at Aetrix Electronics and suitable for automotive engine control units, industrial DSP motion controllers, portable telematics devices, and smart battery management systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TPS3306-20QDRQ1 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 deep expertise in automotive, industrial, and power management ICs.

The TPS3306-Q1 family was designed specifically for automotive-grade dual-voltage supervision in DSP and microprocessor systems, addressing stringent reliability, temperature, and functional safety requirements in modern vehicle electronics.

FAQ

What is the exact SENSE2 threshold voltage for TPS3306-20QDRQ1, and how does it vary with temperature?

The TPS3306-20QDRQ1 has a nominal SENSE2 threshold voltage of 1.85 V at 25°C, with guaranteed range of 1.79 V to 1.91 V across −40°C to 125°C. This 3.2% total variation ensures robust 2.0 V rail supervision without false resets during thermal stress, as confirmed in the Electrical Characteristics table (SGLS241B, page 7).

Can TPS3306-20QDRQ1 be used without connecting the WDI pin, and what is the impact on watchdog functionality?

Yes - leaving WDI unconnected disables the watchdog timer entirely, as stated in the Functional Description (SGLS241B, page 4). The TPS3306-20QDRQ1 then operates solely as a dual-voltage supervisor with power-on reset and PFI monitoring, with no timeout-related RESET assertions. This configuration is valid for systems where software-level watchdogs are implemented elsewhere.

How does the PFI input on TPS3306-20QDRQ1 enable low-battery detection, and what resistor values are recommended?

The PFI input compares against an internal 1.25 V reference; using a 1 MΩ total divider (e.g., R1 = 470 kΩ, R2 = 530 kΩ) scales battery voltage to trip PFO at ~12.5 V for a 12 V system. Per datasheet Figure 7 (SGLS241B, page 5), resistor tolerance must be ≤1% to limit threshold error, and PFI current remains <30 nA, minimizing battery drain.

Is TPS3306-20QDRQ1 pin-compatible with other members of the TPS3306-Q1 family, such as TPS3306-18QDRQ1?

Yes - all TPS3306-Q1 variants (including TPS3306-20QDRQ1, TPS3306-18QDRQ1, and TPS3306-25QDRQ1) share identical SOIC-8 (D) package, pinout, and electrical interface. Only the internal SENSE2 threshold differs (1.68 V, 1.85 V, 2.25 V respectively); no PCB changes are required when substituting within the same package variant.

What is the minimum VDD required for TPS3306-20QDRQ1 to assert a valid RESET signal, and how is this used during cold-start?

The TPS3306-20QDRQ1 defines RESET output when VDD reaches ≥1.1 V, as specified in the Recommended Operating Conditions table (SGLS241B, page 6). This enables early reset assertion during cold-start from weak batteries or slow-ramping supplies, ensuring processors remain held in reset until sufficient supply headroom exists for reliable digital operation.