Texas Instruments TPS3839A09DBZT

Overview

TPS3839A09DBZT from Texas Instruments is an ultralow-power voltage supervisor IC designed for single-supply monitoring in battery-critical systems. It features a factory-trimmed 0.9 V reset threshold, 150 nA typical supply current at 25°C, push-pull RESET output, valid operation down to 0.6 V VDD, and operates across –40°C to +85°C. It is used to safeguard microprocessor startup and brownout recovery in single-cell alkaline-powered devices.

For engineers reviewing the TPS3839A09DBZT datasheet, TPS3839A09DBZT pinout, TPS3839A09DBZT application, or TPS3839A09DBZT equivalent, key selection criteria include reset threshold accuracy (±1% at 25°C), temperature stability of VIT– (±0.02%/°C), transient rejection capability, 200 ms reset delay timing, and compatibility with low-impedance bypassing for high-source-impedance supplies.

Technical Context

The TPS3839A09DBZT implements a precision bandgap-based voltage reference and comparator with hysteresis (54 mV typical) to detect VDD drops below 0.9 V. Its sampling architecture draws only ~15 µA for ~200 µs per measurement cycle, enabling 150 nA average quiescent current.

It lacks a manual reset (MR) input-unlike the TPS3831 family-and uses a 3-pin SOT23-3 (DBZ) package with VDD, GND, and active-low RESET terminals. The push-pull output drives bidirectional reset lines directly but requires series resistance when interfacing with open-drain or weak-pullup microcontroller reset pins.

Key Specifications

Pinout & Package

SOT23-3 (DBZ) package: 2.92 mm × 2.37 mm footprint, surface-mount, lead-free, RoHS-compliant, moisture sensitivity level (MSL) 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with TPS3831A09DQNR, TPS3839A09DBZT saves board space and eliminates MR routing complexity; compared with MAX6375XR29+T, it reduces standby current by 10.7×, extending battery life significantly in portable equipment.

Availability

TPS3839A09DBZT is available at Aetrix Electronics and suitable for portable medical devices, battery-powered meters, wearable electronics, and industrial IoT edge nodes requiring stable component supply over multi-year production cycles.

Supply support for TPS3839A09DBZT 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 company specializing in analog, embedded processing, and power management technologies, with decades of leadership in precision analog ICs and low-power design.

The TPS383x product line was developed specifically for ultralow-power voltage supervision in energy-constrained applications such as coin-cell and single-cell battery systems, emphasizing sub-µA quiescent current and robust brownout detection.

FAQ

What is the minimum supply voltage at which TPS3839A09DBZT guarantees a valid RESET output?

The TPS3839A09DBZT guarantees a valid RESET output down to VDD = 0.6 V, as specified by the V(POR) parameter in the Electrical Characteristics table. Below this voltage, the RESET state is undefined and must not be relied upon for system safety. This 0.6 V POR threshold ensures deterministic reset behavior deeper into battery discharge than many competing supervisors, making TPS3839A09DBZT especially valuable in single-cell alkaline applications where voltage can decay slowly below 0.9 V.

Does TPS3839A09DBZT include a manual reset (MR) input?

No, the TPS3839A09DBZT does not include a manual reset (MR) input. It is a 3-pin device (VDD, GND, RESET) with no MR terminal. The MR function is exclusive to the TPS3831 family (e.g., TPS3831A09DQNR), which uses a 4-pin X2SON package. If manual reset capability is required, TPS3831A09DQNR is the functional counterpart-but TPS3839A09DBZT remains optimal when only supply-voltage supervision is needed and board space is constrained.

What is the recommended bypass capacitor for TPS3839A09DBZT, and why is it necessary?

A 0.1 µF ceramic capacitor is recommended directly at the VDD pin of the TPS3839A09DBZT. This is necessary because the device samples VDD intermittently, drawing ~15 µA for ~200 µs per cycle. Without local bypassing, high source impedance (e.g., long PCB traces or resistive voltage dividers) causes momentary VDD droop during sampling, potentially triggering false resets. The 0.1 µF capacitor maintains stable VDD during sampling events, ensuring reliable threshold detection and eliminating spurious reset assertions in real-world layouts.

How does the reset delay time of TPS3839A09DBZT vary with temperature?

The reset delay time (td) of TPS3839A09DBZT varies from 120 ms (min) to 350 ms (max) across –40°C to +85°C, with 200 ms typical at 25°C. Figure G002 in the datasheet shows td increases slightly with temperature-e.g., ~220 ms at +85°C-due to internal RC timing element drift. This variation is fully characterized and accounted for in system timing budgets; no external compensation is required. Designers should use the 350 ms maximum value for worst-case power-up sequencing analysis.

Can TPS3839A09DBZT drive a microcontroller's bidirectional reset pin directly?

TPS3839A09DBZT can drive a microcontroller's bidirectional reset pin, but a series resistor (typically 1–10 kΩ) is required between RESET and the MCU pin. This protects against contention current when both the TPS3839A09DBZT and MCU attempt to drive the line simultaneously-e.g., during MCU-initiated reset or debug probe activity. Figure 16 in the datasheet illustrates this configuration. Omitting the resistor risks excessive current flow, potential I/O damage, or unpredictable reset behavior, especially with weak internal MCU pull-ups.