Analog Devices Inc. ADM8699AN

Overview

ADM8699AN from Analog Devices is a microprocessor supervisory circuit with integrated watchdog timer, precision 4.65 V voltage monitor, and guaranteed RESET assertion down to VCC = 1 V. It provides power-up/power-down reset, brown-out protection, and 1.6 s typical watchdog timeout for embedded microprocessor systems requiring reliable fault recovery.

For engineers reviewing the ADM8699AN datasheet, ADM8699AN pinout, ADM8699AN application, or ADM8699AN equivalent, key selection considerations include its 8-pin DIP package, WDI three-level input behavior, RESET active-low output with 140–280 ms delay, and compatibility with 5 V ±10% supply rails in industrial temperature environments.

Technical Context

The ADM8699AN implements a precision bandgap-based voltage detector with 40 mV hysteresis and a monostable power-on reset timer. Its watchdog transition detector responds to rising or falling edges on WDI, resetting the 1.6 s timeout period on each valid toggle.

Unlike the ADM8698, the ADM8699AN includes dedicated WDI input logic that disables the watchdog when left floating or driven to midsupply. RESET remains functional at VCC ≥ 1 V, enabling robust low-voltage shutdown sequencing without external support circuitry.

Key Specifications

Pinout & Package

ADM8699AN is housed in an 8-pin plastic DIP (N-8) package with 0.3-inch body width and through-hole mounting. Pin 1 is marked by a notch or dot; pins are numbered counterclockwise from top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX699CPA+ and TPS3823-46DBVR, the ADM8699AN uniquely integrates both precision voltage monitoring and a configurable watchdog in an industry-standard 8-pin DIP, making it the only option among the three that delivers full hardware-level fault detection and recovery without firmware dependency.

Availability

ADM8699AN is available at Aetrix Electronics and suitable for industrial PLC controller monitoring, automotive ECU power supervision, and medical diagnostic instrument boot integrity requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM8699AN 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, communications, automotive, and healthcare markets since 1965.

The ADM8698/ADM8699 family was designed specifically for robust, low-component-count microprocessor supervision in harsh industrial and automotive environments where reliability under voltage stress and temperature variation is critical.

FAQ

What is the function of the WDI pin on the ADM8699AN?

The WDI (Watchdog Input) pin on the ADM8699AN is a three-level input that monitors microprocessor activity. Each rising or falling edge resets the 1.6 s watchdog timer; if no transition occurs within the timeout period, ADM8699AN asserts RESET. WDI can be disabled by leaving it floating or driving it to midsupply (~2.5 V), eliminating need for additional control logic.

Does the ADM8699AN provide RESET assertion when VCC drops below 1 V?

No - the ADM8699AN guarantees RESET assertion *down to* VCC = 1 V, meaning RESET remains functional and correctly asserted as low even when VCC declines to 1 V. Below 1 V, the device ceases operation and RESET behavior is undefined. This feature ensures reliable µP hold-down during deep brown-out conditions before complete power loss.

Can the ADM8699AN be used with a 3.3 V microprocessor system?

The ADM8699AN is specified for VCC = 3.0 V to 5.5 V, but its 4.65 V reset threshold is optimized for 5 V systems. Using it with a 3.3 V supply would cause immediate, permanent RESET assertion since 3.3 V < 4.65 V. For 3.3 V systems, select a supervisor with matching threshold (e.g., ADM809/ADM810 series), not the ADM8699AN.

What is the purpose of the multiple GND pins on the ADM8699AN DIP package?

The ADM8699AN's 8-pin DIP includes three dedicated GND pins (pins 2, 7, and 8) to reduce ground impedance, improve noise immunity, and enhance thermal dissipation. These pins must be connected to a common low-impedance ground plane on the PCB - separating them or routing individually degrades reset timing accuracy and increases susceptibility to supply noise.

How does the ADM8699AN differ from the ADM8698AN in terms of functionality?

The ADM8699AN adds a dedicated WDI input and internal watchdog transition detector not present in the ADM8698AN. Both share identical voltage monitoring, reset timing, and output drive specs. The ADM8699AN is the only version capable of detecting µP software hangs via I/O toggling; the ADM8698AN provides power-supply-only supervision without runtime activity checking.