Analog Devices Inc. ADM709TARZ

Overview

ADM709TARZ from Analog Devices is a precision power supply monitor IC with active-low reset output, 3.08 V threshold, 140 ms minimum power-on reset pulse, and operation down to 1 V supply voltage-designed for reliable microprocessor reset in +3.3 V and +3 V systems.

For engineers reviewing the ADM709TARZ datasheet, ADM709TARZ pinout, ADM709TARZ application, or ADM709TARZ equivalent, key selection criteria include reset threshold accuracy (±70 mV), guaranteed RESET assertion at VCC ≥ 1 V, glitch-immune monitoring, SOIC-8 packaging, and compatibility with bidirectional µP reset lines via external series resistor.

Technical Context

The ADM709TARZ implements a comparator-based reset generator with internal timing circuitry that holds RESET low for ≥140 ms after VCC rises above 3.08 V (typ), ensuring stable processor initialization. It features no-connect pins (1,4,5,6,8) and operates across –40°C to +85°C with quiescent current as low as 35 µA at VCC < 3.6 V.

Its RESET output remains functional down to VCC = 1 V, enabling controlled shutdown sequencing; glitch immunity is achieved via internal filtering, and external 0.1 µF decoupling on VCC further suppresses transients without requiring additional logic.

Key Specifications

Pinout & Package

ADM709TARZ is housed in an 8-pin SOIC (SO-8) package with gull-wing leads, 1.27 mm pitch, and JEDEC MS-012AC compliance. Pin 1 is marked by notch or dot; pins 1, 4, 5, 6, and 8 are internally unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX709TSA+ and TPS3808G30DBVR, the ADM709TARZ uniquely guarantees RESET assertion down to 1 V VCC and delivers tighter threshold accuracy (±70 mV) in a pin-compatible SOIC-8 package-critical for brownout resilience in industrial and automotive edge nodes.

Availability

ADM709TARZ is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical handheld diagnostics, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM709TARZ 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The ADM709 belongs to Analog Devices' precision power supply supervisor product line, engineered specifically for deterministic microprocessor reset in noise-prone, wide-temperature environments with minimal external components.

FAQ

What is the exact reset threshold voltage of the ADM709TARZ?

The ADM709TARZ has a nominal reset threshold of 3.08 V, with a guaranteed range of 3.00 V to 3.15 V over the full –40°C to +85°C operating temperature range. This value is factory-trimmed and specified in the Absolute Maximum Ratings table of the official Analog Devices datasheet Rev. 0. The ADM709TARZ uses this precise threshold to reliably detect undervoltage conditions on +3.3 V and +3 V power rails.

Does the ADM709TARZ support operation below 1.2 V VCC?

Yes-the ADM709TARZ is explicitly guaranteed to maintain functional RESET output down to VCC = 1.0 V, as confirmed in the "RESET at Voltages < 1 V" section and electrical specifications. Below 1 V, a 100 kΩ pull-down resistor is recommended to ensure RESET stays asserted. This capability makes the ADM709TARZ uniquely suited for deep brownout recovery scenarios where other supervisors fail.

Is the ADM709TARZ pin-compatible with the MAX709 series?

The ADM709TARZ is a functional upgrade for the MAX709, sharing identical SOIC-8 pinout (VCC=2, GND=3, RESET=7), same no-connect pin assignments (1,4,5,6,8), and matching reset polarity and timing architecture. However, it improves threshold accuracy and extends low-VCC operation-no PCB changes are required for direct replacement in existing MAX709T designs.

What is the minimum power-on reset pulse width for the ADM709TARZ?

The ADM709TARZ guarantees a minimum power-on reset pulse width of 140 ms after VCC rises above the 3.08 V threshold, with typical duration of 280 ms and maximum of 380 ms. This timing is generated by an internal RC-controlled timer and ensures sufficient stabilization time for microprocessors and associated peripherals before release from reset.

Can the ADM709TARZ drive a microcontroller reset pin directly?

Yes-the ADM709TARZ RESET output is an active-low, open-drain compatible signal capable of sinking up to 1.2 mA at 0.3 V, making it suitable for direct interface with most µP reset inputs. For bidirectional reset lines (e.g., MC68HC11), a 4.7 kΩ series resistor is recommended to prevent contention, as documented in Figure 6 of the ADM709 datasheet.