Texas Instruments TPS3840DL28DBVR

Overview

TPS3840DL28DBVR from Texas Instruments is a nano-power, high-input-voltage supervisor IC with active-low open-drain reset output, 2.8 V fixed threshold (±1.5% max), 300 nA typical supply current, and programmable reset delay up to 6.2 s via external capacitor on CT pin. It monitors power rails in battery-powered and industrial systems where ultra-low quiescent current and precise voltage supervision are critical.

For engineers reviewing the TPS3840DL28DBVR datasheet, TPS3840DL28DBVR pinout, TPS3840DL28DBVR application, or TPS3840DL28DBVR equivalent, key selection considerations include its 2.8 V detection threshold accuracy, SOT-23-5 package footprint, open-drain RESET topology requiring external pull-up, MR input for manual reset assertion, and CT-pin-based delay programming - all validated across –40°C to +125°C.

Technical Context

The TPS3840DL28DBVR implements a precision bandgap-referenced comparator with built-in hysteresis (100 mV typical for 2.8 V threshold) to prevent chatter during voltage recovery. Its internal state machine enforces a minimum startup delay of 220 µs (typical) before enabling reset release, and integrates glitch immunity on both VDD and MR inputs - rejecting transients <10 µs at 5% overdrive.

Reset assertion occurs when VDD falls below 2.8 V or MR is pulled low; deassertion requires VDD to rise above 2.9 V (2.8 V + 100 mV hysteresis) *and* expiration of the programmed tD delay. The CT pin's 500 kΩ (typical) internal resistance sets the RC time constant with an external capacitor, enabling deterministic delay tuning without external timing ICs.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm footprint, surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3840PL28DBVR, the TPS3840DL28DBVR saves one passive component (pull-up resistor) but requires careful trace routing to avoid leakage-induced false releases; versus MAX6326UT28+T, it trades higher design flexibility (MR, CT, nano-I_CC) for greater configuration effort.

Availability

TPS3840DL28DBVR is available at Aetrix Electronics and suitable for smart metering, portable medical devices, fire safety systems, and industrial PLC modules requiring stable component supply with full lifecycle support.

Supply support for TPS3840DL28DBVR 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 deep expertise in power management, signal chain, and real-time control ICs.

The TPS3840 family was designed specifically for ultra-low-power, high-voltage supervision in battery-backed and industrial equipment - prioritizing nanoscale current draw, wide input range, and robust noise immunity over cost-optimized simplicity.

FAQ

What is the exact threshold voltage of TPS3840DL28DBVR and how accurate is it?

The TPS3840DL28DBVR has a factory-trimmed negative-going input threshold (VIT−) of 2.8 V, with accuracy of ±1.5% maximum over –40°C to +125°C. Typical accuracy is ±1%, and hysteresis is 100 mV (typical), meaning the rising threshold (VIT+) is 2.9 V. This is verified in TI's SNVSB03E datasheet Section 6.5 Electrical Characteristics.

Does TPS3840DL28DBVR require an external pull-up resistor on the RESET pin?

Yes, TPS3840DL28DBVR features an open-drain active-low RESET output and requires an external pull-up resistor to VDD or another logic rail. Typical values range from 10 kΩ to 100 kΩ depending on rise time and bus capacitance. This is specified in the "Pin Configuration and Functions" section of the TPS3840DL28DBVR datasheet.

How is the reset delay time programmed on TPS3840DL28DBVR?

The reset delay (tD) on TPS3840DL28DBVR is programmed by connecting an external capacitor between the CT pin (Pin 5) and GND. With no capacitor, tD = 50 µs (min); with 10 µF, tD ≈ 6.2 s (max). The relationship follows tD = 618937 × CCT_EXT + 50 µs, where CCT_EXT is in farads - confirmed in Section 7.3.2 of the TPS3840DL28DBVR datasheet.

Can TPS3840DL28DBVR monitor a 24 V supply directly?

No, TPS3840DL28DBVR cannot monitor 24 V directly - its absolute maximum VDD rating is 12 V. To supervise 24 V rails, use a precision resistor divider to scale the voltage down to ≤10 V at the VDD pin. Ensure divider current remains << 700 nA to avoid loading error; TI recommends ≥1 MΩ total divider resistance per Section 8.2 of the TPS3840DL28DBVR datasheet.

What is the function of the MR pin on TPS3840DL28DBVR and what voltage levels trigger it?

The MR (Manual Reset) pin on TPS3840DL28DBVR is an active-low input that forces RESET assertion when pulled below V_{MR_L} = 600 mV (max). It releases reset when pulled above V_{MR_H} = 0.7 × VDD (min). An internal 100 kΩ pull-up keeps MR inactive when floating. These thresholds are specified in Table 6-5 of the TPS3840DL28DBVR datasheet.