Analog Devices Inc. ADM706AR

Overview

ADM706AR from Analog Devices is a low-cost microprocessor supervisory circuit designed for 5 V supply monitoring in embedded systems. It provides active-low reset output with 4.40 V threshold, 200 ms reset pulse width, 190 μA quiescent current, and integrated watchdog timer (1.60 sec timeout), used to ensure reliable power-up sequencing and stall detection in industrial controllers.

For engineers reviewing the ADM706AR datasheet, ADM706AR pinout, ADM706AR application, or ADM706AR equivalent, key selection criteria include reset threshold accuracy (4.40 V ±150 mV), guaranteed RESET validity down to VCC = 1 V, debounced manual reset input (MR), power-fail comparator (PFI/PFO), and SOIC-8 package compatibility with standard PCB layouts.

Technical Context

The ADM706AR implements a precision bandgap-based voltage reference (1.25 V) feeding a comparator that triggers reset when VCC falls below 4.40 V with 40 mV hysteresis. Its independent watchdog circuit monitors WDI transitions and asserts WDO low after 1.60 sec of inactivity - cleared by any edge on WDI or by RESET assertion.

It integrates three functional blocks: (1) power-supply monitor with reset generator, (2) watchdog timer with edge-sensitive input and open-drain WDO output, and (3) power-fail comparator with 1.25 V reference and PFO open-drain output. All logic inputs (MR, WDI, PFI) are TTL/CMOS-compatible with defined thresholds and internal pull-up (MR) or high-impedance (WDI, PFI).

Key Specifications

Pinout & Package

ADM706AR is housed in an 8-lead SOIC_N (R-8) package per JEDEC MS-012-AA, with 1.27 mm lead pitch, 5.00 mm × 3.99 mm body, and gull-wing leads. Thermal resistance θJA = 110°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706CSA+ and TPS3808G33DBVR, the ADM706AR uniquely combines 5 V supervision, integrated PFI/PFO comparator, and SOIC-8 compatibility - making it optimal for industrial designs requiring dual-supply monitoring and legacy footprint alignment.

Availability

ADM706AR is available at Aetrix Electronics and suitable for industrial PLCs, embedded controllers, medical diagnostic instruments, and telecom remote terminals requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for ADM706AR 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 ADM705/ADM706 family was engineered specifically for robust, low-cost microprocessor supervision in harsh industrial environments - emphasizing brownout resilience, watchdog autonomy, and multi-rail monitoring capability.

FAQ

What is the reset threshold voltage for ADM706AR and how tightly is it specified?

The ADM706AR has a nominal reset threshold of 4.40 V, with a guaranteed range of 4.25 V to 4.50 V over the full industrial temperature range (−40°C to +85°C). This specification ensures reliable reset assertion before the 5 V supply falls into the microprocessor's undefined operating region, and is confirmed in Table 1 of the Rev. H datasheet under "Reset Threshold" for ADM706/ADM708 devices.

Can ADM706AR generate a valid reset signal when VCC drops below 1.2 V?

Yes - the ADM706AR guarantees valid RESET output down to VCC = 1.0 V, as explicitly stated in the General Description and verified in Figure 6 of the datasheet. At VCC = 1.0 V, RESET remains low with a sink capability of 50 µA, ensuring the microprocessor stays held in reset during deep brownout. This behavior is intrinsic to the ADM706AR's internal design and does not require external components.

How does the watchdog timer in ADM706AR interact with the manual reset input (MR)?

In the ADM706AR, the watchdog timer operates independently but can trigger system reset via MR: when WDO goes low due to timeout, connecting WDO to MR forces a hardware reset. The internal timer resets on every WDI transition (rising or falling edge) and also clears automatically whenever RESET is asserted low - ensuring the watchdog restarts cleanly after each power-up or manual reset event.

Is ADM706AR RoHS compliant and what is its packaging format?

Yes, the ADM706AR is RoHS compliant (denoted by the "Z" suffix in ordering codes like ADM706ARZ), and is supplied in an 8-lead SOIC_N (R-8) package per JEDEC MS-012-AA. The device uses lead-free terminations and meets J-STD-020 moisture sensitivity level 1, supporting standard reflow profiles without special handling requirements.

Does ADM706AR support active-high reset output for processors requiring that logic polarity?

No - the ADM706AR provides only an active-low RESET output (Pin 7). For active-high reset, designers must select the pin-compatible ADM707AR or ADM708AR, which feature complementary RESET and RESET outputs. The ADM706AR's functional block diagram (Figure 1) and Pin Function Descriptions (Table 3) confirm RESET is active-low only; no internal inversion or dual-output capability exists in this variant.