Texas Instruments LM809M3-2.63

Overview

LM809M3-2.63 from Texas Instruments is a 3-pin SOT-23 microprocessor reset supervisor IC with a factory-programmed 2.63 V ±3% precision reset threshold, 240 ms typical active-low reset timeout, and 15 µA typical supply current. It monitors VCC in low-voltage embedded systems and asserts RESET during power-up, brown-out, or power-down - used in programmable logic controllers and battery-powered instrumentation.

For engineers reviewing the LM809M3-2.63 datasheet, LM809M3-2.63 pinout, LM809M3-2.63 application, or LM809M3-2.63 equivalent, key selection criteria include guaranteed reset assertion for VCC ≥1 V, immunity to ≤20 µs VCC transients below threshold, operation across –40°C to 105°C, and compatibility with 3.0 V nominal supply rails requiring 85–90% undervoltage detection.

Technical Context

The LM809M3-2.63 implements a precision bandgap-based voltage comparator with internal hysteresis to detect VCC falling below 2.63 V, triggering an active-low open-drain RESET output. Its internal timing circuit ensures minimum 140 ms (typical 240 ms) reset pulse width after VCC recovers above threshold.

It operates over full industrial temperature range (–40°C to 105°C) with guaranteed functionality down to VCC = 1.0 V, supports transient immunity up to 100 mV overdrive for ≤20 µs, and features low 30 ppm/°C reset threshold temperature coefficient for stable trip points across thermal conditions.

Key Specifications

Pinout & Package

SOT-23 (DBZ) package, 2.92 mm × 1.30 mm body size, 3-pin surface-mount outline with gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD3-T and TPS3808G12DBVR, the LM809M3-2.63 delivers longer guaranteed reset duration and lowest quiescent current in a drop-in fixed-threshold solution - critical for industrial systems where deterministic boot reliability outweighs configurability.

Availability

LM809M3-2.63 is available at Aetrix Electronics and suitable for programmable logic controllers, portable data loggers, industrial HMI panels, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM809M3-2.63 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 industrial ICs.

The LM809 product line delivers cost-optimized, precision voltage supervisors for microprocessor reset functions - designed specifically for robust operation in factory automation, building controls, and battery-powered instrumentation.

FAQ

What is the exact reset threshold voltage of the LM809M3-2.63 and how does it vary with temperature?

The LM809M3-2.63 has a factory-programmed reset threshold of 2.63 V ±3% at 25°C. Over the full operating range (–40°C to +105°C), the threshold varies by ±30 ppm/°C, resulting in a maximum deviation of ±15 mV. At 105°C, the threshold remains within 2.50 V to 2.76 V, ensuring consistent undervoltage detection for 3.0 V systems across industrial environments.

Does the LM809M3-2.63 provide a valid RESET output when VCC falls below 1.0 V?

No - the LM809M3-2.63 guarantees RESET output validity only for VCC ≥1.0 V. Below this level, the internal circuitry cannot maintain defined logic states, and the RESET pin enters high-impedance. To prevent floating conditions, TI recommends adding a 100 kΩ pull-down resistor from RESET to GND when interfacing with CMOS inputs in low-VCC scenarios.

What is the minimum reset pulse width guaranteed by the LM809M3-2.63 across temperature?

The LM809M3-2.63 guarantees a minimum reset active timeout of 140 ms over –40°C to +85°C, and 100 ms from +85°C to +105°C. The typical value is 240 ms at 25°C. This ensures compliance with JEDEC JESD78 requirements for microprocessor reset hold time, even under worst-case thermal and process variations.

Can the LM809M3-2.63 be used with a 3.3 V supply rail?

Yes - the LM809M3-2.63 is fully compatible with 3.3 V supplies. Its 2.63 V threshold corresponds to 79–82% of 3.3 V, placing it within the standard undervoltage detection window for 3.3 V systems. It operates reliably across the full 1.0–5.5 V VCC range and draws only 15 µA, making it ideal for 3.3 V embedded applications.

Is the LM809M3-2.63 pin-compatible with other members of the LM809 family?

Yes - all LM809 variants (e.g., LM809M3-2.93, LM809M3-4.63) share identical SOT-23 (DBZ) 3-pin packaging and pinout (GND, RESET, VCC). They differ only in factory-programmed reset threshold voltage, allowing direct substitution in designs where threshold adjustment is acceptable without PCB modification.