Texas Instruments LM3724EM5-4.63/NOPB

Overview

LM3724EM5-4.63/NOPB from Texas Instruments is an active-low open-drain microprocessor reset supervisor IC designed for precise 5V supply monitoring. It asserts reset when VCC falls below 4.63 V ±1.8%, maintains reset for ≥100 ms after VCC recovers, guarantees valid output down to VCC = 1 V, and draws only 6 µA typical supply current. It is used in industrial embedded systems requiring reliable power-on initialization and brownout protection.

For engineers reviewing the LM3724EM5-4.63/NOPB datasheet, LM3724EM5-4.63/NOPB pinout, LM3724EM5-4.63/NOPB application, or LM3724EM5-4.63/NOPB equivalent, key selection criteria include its 4.63 V threshold accuracy, −40°C to +125°C extended temperature range, SOT-23-5 open-drain output configuration, manual reset (MR) debouncing, and transient immunity for robust system-level reset control.

Technical Context

The LM3724EM5-4.63/NOPB integrates a precision voltage comparator with 30 ppm/°C tempco, internal 1.225 V reference, one-shot timer for 190 ms typical reset timeout, and fully debounced MR input with 22 kΩ internal pull-up. Its open-drain RESET output enables wired-OR configurations and logic-level translation via external pull-up.

It operates across VCC = 1.0 V to 5.5 V, supports manual reset assertion with <10 µs minimum pulse width, and provides glitch immunity on both VCC and MR inputs (≤100 ns). The device meets industrial and extended temperature grade specifications with guaranteed performance over −40°C to +125°C.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.9 mm × 1.6 mm × 1.45 mm body, gull-wing leads, RoHS-compliant matte tin (Sn) finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX811TEUS+T, LM3724EM5-4.63/NOPB offers open-drain output and extended temperature support; compared with TPS3808G33DBVR, it delivers factory-trimmed 4.63 V accuracy without external components and lower supply current-critical for fixed-threshold, low-power 5 V systems.

Availability

LM3724EM5-4.63/NOPB is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and portable medical equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM3724EM5-4.63/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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability ICs.

The LM372x family was designed specifically for microprocessor supervisory functions in cost-sensitive, space-constrained applications demanding precision voltage monitoring, low power, and robust reset timing-particularly in industrial and automotive edge nodes.

FAQ

What is the exact reset threshold voltage of the LM3724EM5-4.63/NOPB?

The LM3724EM5-4.63/NOPB has a factory-programmed reset threshold of 4.63 V with ±1.8% tolerance over the full −40°C to +125°C operating range. This value is trimmed during production and specified in the Electrical Characteristics table of the SNVS154E datasheet. The threshold applies directly to 5 V nominal supply rails and ensures reliable detection of brownout conditions before critical logic failure occurs. LM3724EM5-4.63/NOPB maintains this accuracy without external components.

Does the LM3724EM5-4.63/NOPB support manual reset functionality?

Yes, the LM3724EM5-4.63/NOPB includes a dedicated Manual Reset (MR) input on Pin 4. It features internal 22 kΩ pull-up resistance and is fully debounced. Asserting MR low for >10 µs initiates a reset pulse lasting ≥100 ms. The MR pin accepts logic-level signals and tolerates glitches ≤100 ns. This function enables pushbutton-initiated system reset without external filtering, and LM3724EM5-4.63/NOPB holds reset active even if MR returns high before timeout completion.

What is the output configuration of the LM3724EM5-4.63/NOPB and why does it matter?

The LM3724EM5-4.63/NOPB features an active-low open-drain RESET output on Pin 3. This configuration requires an external pull-up resistor but enables wired-OR connections with other supervisors, supports mixed-voltage logic interfacing (e.g., pull-up to 3.3 V while VCC = 5 V), and avoids contention in multi-source reset buses. Unlike push-pull outputs, open-drain allows safe parallel operation without additional logic gates-making LM3724EM5-4.63/NOPB ideal for complex systems with redundant supervision.

Can the LM3724EM5-4.63/NOPB operate reliably below 1 V supply voltage?

No-the LM3724EM5-4.63/NOPB guarantees valid RESET output only for VCC ≥1 V. Below 1 V, the internal circuitry cannot maintain defined logic states or sink rated current. However, the datasheet recommends adding a 100 kΩ pull-down resistor from RESET to GND to ensure a known low state during deep undervoltage events. This external component ensures deterministic behavior where LM3724EM5-4.63/NOPB itself ceases guaranteed operation, preserving system safety during catastrophic rail collapse.

Is the LM3724EM5-4.63/NOPB compatible with legacy MAX811-based designs?

The LM3724EM5-4.63/NOPB shares the same 4.63 V threshold and functional intent as the MAX811 series but differs in output architecture: LM3724EM5-4.63/NOPB uses open-drain, whereas MAX811 variants use push-pull. Direct replacement requires verifying that the target system's RESET net is configured for open-drain (i.e., includes a pull-up). If the existing design relies on push-pull drive strength or lacks a pull-up, board-level modifications are needed. LM3724EM5-4.63/NOPB also extends temperature range to +125°C and improves supply current efficiency.