Analog Devices Inc. ADM706SAR-REEL

Overview

ADM706SAR-REEL from Analog Devices is a 3 V microprocessor supervisory circuit with active-low reset output, 2.93 V reset threshold, 200 ms reset pulse width, 100 µA quiescent current, and integrated watchdog timer. It monitors power supply integrity during power-up, brownout, and shutdown in embedded controllers and battery-powered instrumentation.

For engineers reviewing the ADM706SAR-REEL datasheet, ADM706SAR-REEL pinout, ADM706SAR-REEL application, or ADM706SAR-REEL equivalent, key selection criteria include reset threshold accuracy (±70 mV), guaranteed RESET validity down to VCC = 1 V, debounced manual reset input, independent watchdog timeout (1.6 sec), and dual-supply monitoring via PFI/PFO.

Technical Context

The ADM706SAR-REEL implements a precision bandgap voltage reference (2.93 V ±70 mV) for VCC monitoring and a separate 1.25 V comparator for power-fail detection on the PFI input. Its internal watchdog timer resets on any WDI transition and times out after 1.6 sec of inactivity, driving WDO low to trigger NMI or system reset.

Reset generation is synchronized to VCC crossing the threshold with 200 ms minimum assertion time, and remains valid even as VCC drops to 1 V. The MR input features internal 70 µA pull-up and hardware debouncing, eliminating external RC networks for switch-based reset initiation.

Key Specifications

Pinout & Package

ADM706SAR-REEL is housed in an 8-lead SOIC_N (R-8) package per JEDEC MS-012-AA, with 1.27 mm lead pitch and 5.00 mm × 4.00 mm body dimensions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM706SAR-REEL, MAX706SESA+ offers lower quiescent current but omits watchdog capability, while TPS3808G33DBVR reduces power further but sacrifices PFI monitoring and MR debouncing-making ADM706SAR-REEL the only option supporting full three-function supervision (reset, watchdog, power-fail) in a single SOIC-8 device.

Availability

ADM706SAR-REEL is available at Aetrix Electronics and suitable for industrial controllers, battery-powered instrumentation, embedded medical devices, and communications modules requiring stable component supply across extended temperature ranges.

Supply support for ADM706SAR-REEL 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.

The ADM706 family was designed specifically for robust microprocessor supervision in mission-critical embedded systems, emphasizing guaranteed reset validity, low-power operation, and integrated fault-detection features.

FAQ

What is the reset threshold voltage of the ADM706SAR-REEL?

The ADM706SAR-REEL has a nominal reset threshold of 2.93 V, with a tolerance of ±70 mV (2.85 V to 3.00 V). This value is specified over the full industrial temperature range (−40°C to +85°C) and ensures reliable detection of brownout conditions on 3 V supply rails. The threshold is derived from an internal precision bandgap reference and does not require external calibration. ADM706SAR-REEL maintains this specification under all operating conditions defined in the datasheet.

Does the ADM706SAR-REEL include a watchdog timer?

Yes, the ADM706SAR-REEL includes a fully integrated watchdog timer with a nominal timeout period of 1.6 seconds. The timer resets on any rising or falling edge at the WDI pin and asserts the WDO output low if no transition occurs within the timeout window. WDO is open-drain and requires an external pull-up resistor. The timer is also cleared automatically when RESET is asserted, ensuring coordinated behavior during power-up or manual reset events. ADM706SAR-REEL implements this function without external components.

Can the ADM706SAR-REEL monitor a second power supply?

Yes, the ADM706SAR-REEL can monitor a second supply using its dedicated PFI (Power Fail Input) and PFO (Power Fail Output) pins. The internal 1.25 V comparator compares PFI voltage against a precision reference; when PFI falls below 1.25 V, PFO goes low. By configuring a resistor divider from the secondary supply to PFI, designers can set custom trip points-for example, detecting battery voltage drop below 2.5 V. ADM706SAR-REEL supports this dual-supply monitoring alongside primary VCC supervision.

What is the minimum supply voltage at which ADM706SAR-REEL guarantees valid RESET output?

The ADM706SAR-REEL guarantees valid RESET output down to VCC = 1 V. Below this level, the internal output stage cannot maintain full logic low drive strength, but within the 1 V to 5.5 V operating range, RESET remains a well-defined active-low signal with VOL ≤ 0.3 V at ISINK = 1.2 mA. This specification ensures deterministic microprocessor reset behavior during deep brownout and uncontrolled power-down sequences. ADM706SAR-REEL meets this guarantee across the full −40°C to +85°C temperature range.

Is the manual reset input (MR) of ADM706SAR-REEL debounced internally?

Yes, the MR input of ADM706SAR-REEL is hardware-debounced with a built-in 200 ms timeout, eliminating the need for external RC filters or firmware debouncing routines. It features an internal 70 µA pull-up current that holds MR high when floating, enabling direct connection to momentary switches without external biasing. The input is TTL/CMOS-compatible and responds to logic-low transitions below 0.6 V. This internal debouncing is integral to ADM706SAR-REEL's architecture and operates independently of VCC level within its rated range.