Texas Instruments SM72240MFX-3.08/NOPB

Overview

SM72240MFX-3.08/NOPB from Texas Instruments is a renewable-energy-grade microprocessor supervisory circuit designed to monitor 3.3V supply rails and assert an active-low open-drain RESET signal during power-up, brown-out, or manual reset events. It features a factory-programmed 3.08V reset threshold (±0.05V), 190 ms typical reset timeout, operation from −40°C to +125°C, and ultra-low 7 µA typical supply current at 3.6V - enabling reliable system initialization in solar-powered and industrial embedded controllers.

For engineers reviewing the SM72240MFX-3.08/NOPB datasheet, SM72240MFX-3.08/NOPB pinout, SM72240MFX-3.08/NOPB application, or SM72240MFX-3.08/NOPB equivalent, key selection criteria include its precise 3.08V threshold for 3.3V systems, guaranteed reset assertion down to VCC ≥1V, MR input debouncing with internal 22 kΩ pull-up, and SOT-23 (DBV) package compatibility with space-constrained PCB layouts.

Technical Context

The SM72240MFX-3.08/NOPB integrates three comparators - a precision reset comparator with 30 ppm/°C tempco, a manual reset (MR) comparator with 0.25×VCC thresholds, and a low-line detector - feeding into reset logic with a one-shot timer. Its internal 1.225V reference enables stable threshold generation across temperature.

It delivers deterministic reset behavior: RESET remains asserted for ≥100 ms after VCC rises above 3.08V, with 190 ms typical timeout; MR pulses as short as 10 µs trigger reset with 2 µs propagation delay; and the open-drain output supports pull-up to any voltage ≤5.5V, enabling level-shifting across mixed-voltage domains.

Key Specifications

Pinout & Package

SOT-23 (DBV) 5-pin package - 2.9 mm × 1.6 mm footprint, 1.45 mm max height, JEDEC MO-178 compliant, with pin 1 index area and Q3 quadrant orientation on tape.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor reset circuit applications.

Compared with MAX811TEUS+T and TPS3808G30DBVR, the SM72240MFX-3.08/NOPB uniquely combines extended-temperature operation, factory-trimmed 3.08V accuracy, internal MR pull-up, and fixed 190 ms timeout - making it optimal for solar, industrial, and energy-metering designs where reliability and component count reduction are prioritized over programmability or sub-µA quiescent current.

Availability

SM72240MFX-3.08/NOPB is available at Aetrix Electronics and suitable for solar microinverters, industrial PLC controllers, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SM72240MFX-3.08/NOPB 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 delivering analog and embedded processing solutions, with leadership in power management, signal chain, and microcontrollers.

The SM72240 product line was developed specifically for renewable-energy applications - emphasizing precision voltage monitoring, extended temperature operation, and ultra-low power consumption in solar PV systems and grid-tied inverters.

FAQ

What is the exact reset threshold voltage of the SM72240MFX-3.08/NOPB?

The SM72240MFX-3.08/NOPB has a factory-programmed reset threshold of 3.08V, with a guaranteed tolerance of ±0.05V over the full −40°C to +125°C operating range. This value is laser-trimmed during production and documented in the Electrical Characteristics table of the SNIS154C datasheet. The 3.08V threshold is optimized for reliable monitoring of nominal 3.3V power rails in solar and industrial systems.

Does the SM72240MFX-3.08/NOPB require an external pull-up resistor on the RESET pin?

Yes, the SM72240MFX-3.08/NOPB features an active-low open-drain RESET output and requires an external pull-up resistor to a valid logic supply (≤5.5V). A 100 kΩ resistor is recommended for most applications to ensure proper voltage levels while limiting sink current to <10 mA. The datasheet confirms that the RESET output remains valid for VCC ≥1V, but the pull-up must be externally provided.

Can the SM72240MFX-3.08/NOPB operate with a 3.3V supply, and what is its minimum functional VCC?

Yes, the SM72240MFX-3.08/NOPB is explicitly designed to monitor 3.3V supplies and operates correctly with VCC as low as 1.0V. Its RESET output remains valid down to VCC = 1V, and the internal circuitry functions across the full 1.0V–5.5V range. This capability ensures fail-safe reset assertion during deep brown-out conditions common in battery-backed or solar-harvested systems.

What is the purpose of the dual GND pins (pins 1 and 2) on the SM72240MFX-3.08/NOPB?

Pins 1 and 2 on the SM72240MFX-3.08/NOPB are both connected to the device substrate and serve as dedicated ground terminals. This dual-GND configuration improves thermal dissipation and reduces ground impedance, enhancing noise immunity in electrically noisy environments such as solar inverters and industrial motor drives. Both pins must be connected to the system ground plane for optimal performance.

Is the SM72240MFX-3.08/NOPB pin-compatible with the MAX811 series?

The SM72240MFX-3.08/NOPB is compatible with MAX811/812 applications per TI's official documentation, but it is not pin-to-pin identical. While both use 5-pin SOT-23 packages, the SM72240 places GND on pins 1 and 2, RESET on pin 3, MR on pin 4, and VCC on pin 5 - differing from MAX811's pinout (VCC, GND, RESET, MR, GND). Board redesign is required for direct replacement; functional substitution is possible with layout adaptation.