Analog Devices Inc. ADM709LAN

Overview

ADM709LAN from Analog Devices is a precision power supply monitor IC with active-low reset output, 4.65 V threshold, 140 ms minimum power-on reset pulse, and operation down to 1 V supply voltage; used for reliable microprocessor reset in industrial embedded systems during power-up, brownout, and power-down events.

For engineers reviewing the ADM709LAN datasheet, ADM709LAN pinout, ADM709LAN application, or ADM709LAN equivalent, key selection considerations include reset threshold accuracy (±0.15 V), guaranteed RESET functionality at VCC ≥ 1 V, 35 µA typical quiescent current, and compatibility with +5 V supply rails in N-8 DIP packaging.

Technical Context

The ADM709LAN integrates a precision voltage comparator and internal timer to generate a clean, glitch-immune active-low reset signal. It monitors VCC against a fixed 4.65 V threshold and asserts RESET until VCC exceeds that level and remains stable for ≥140 ms.

RESET remains functional even as VCC drops to 1 V, ensuring controlled shutdown; no external components are required for basic operation, though a 0.1 µF bypass capacitor on VCC improves transient immunity and a 100 kΩ pull-down enables valid RESET below 1 V.

Key Specifications

Pinout & Package

ADM709LAN is housed in an 8-pin plastic DIP (N-8) package with 0.3 inch width, through-hole mounting, and industry-standard pin spacing. Pins 1, 4, 5, 6, and 8 are internally unconnected (NC); only VCC (Pin 2), GND (Pin 3), and RESET (Pin 7) are functional.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply monitor applications.

Compared with MAX709CPA+ and TPS3808G33DBVR, the ADM709LAN offers unique combination of fixed 4.65 V accuracy, N-8 DIP form factor, guaranteed 1 V operation, and 35 µA IQ-making it optimal for legacy +5 V industrial control boards where layout change is prohibited.

Availability

ADM709LAN is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded data acquisition systems, and medical diagnostic instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM709LAN 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

Analog Devices is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM709 belongs to Analog Devices' power monitoring and reset supervisor product line, engineered specifically for deterministic, low-risk microprocessor reset in industrial and instrumentation applications where supply voltage integrity is critical.

FAQ

What is the exact reset threshold voltage of the ADM709LAN?

The ADM709LAN has a nominal reset threshold of 4.65 V, with a guaranteed range of 4.50 V to 4.75 V over the full –40°C to +85°C operating temperature range. This tight tolerance ensures consistent detection of +5 V supply brownouts without false triggering or missed events. The ADM709LAN threshold is factory-trimmed and does not require external calibration.

Does the ADM709LAN support operation below 1 V on VCC?

No-the ADM709LAN RESET output is guaranteed functional down to 1 V VCC, but not below. If VCC falls below 1 V, RESET may become indeterminate. To maintain a defined low state under deep undervoltage, a 100 kΩ pull-down resistor between RESET and GND is recommended per the datasheet Figure 5. This ensures safe microprocessor shutdown even during catastrophic power collapse.

Can the ADM709LAN replace the MAX709 in existing designs?

Yes-the ADM709LAN is a direct functional upgrade for the MAX709, sharing identical 4.65 V threshold, pinout (N-8 DIP), and timing behavior. It improves upon the MAX709 with lower quiescent current (35 µA vs. ~100 µA), enhanced glitch immunity, and guaranteed operation down to 1 V VCC. No PCB changes are needed when substituting ADM709LAN for MAX709 in legacy +5 V systems.

What is the minimum power-on reset pulse width of the ADM709LAN?

The ADM709LAN guarantees a minimum power-on reset pulse width of 140 ms after VCC rises above the 4.65 V threshold. Typical duration is 280 ms, and maximum is 380 ms. This interval provides ample time for +5 V rails and microprocessors to stabilize before releasing reset-critical for avoiding boot failures in industrial controllers and instrumentation.

Which pins of the ADM709LAN are unused and must be left unconnected?

Pins 1, 4, 5, 6, and 8 of the ADM709LAN are designated NC (No Connect) and must remain unconnected on the PCB. These pins are not bonded internally and serve only mechanical or packaging purposes. Connecting them risks introducing noise coupling, unintended current paths, or solder joint reliability issues-especially in high-vibration industrial environments.