Analog Devices Inc. ADM708RAN

Overview

ADM708RAN from Analog Devices is a 3 V microprocessor supervisory circuit with dual active-high/active-low reset outputs, 2.63 V precision voltage monitoring threshold, 200 ms reset pulse width, and power-fail warning capability via PFI/PFO. It ensures reliable system reset during power-up, brownout, or supply failure in embedded controllers and battery-powered instrumentation.

For engineers reviewing the ADM708RAN datasheet, ADM708RAN pinout, ADM708RAN application, or ADM708RAN equivalent, key selection considerations include its dual-reset output architecture, guaranteed RESET validity down to 1 V VCC, debounced manual reset input, and compatibility with 3 V/3.3 V supply domains in industrial and portable systems.

Technical Context

The ADM708RAN implements a precision bandgap-based voltage reference (2.63 V) for supply monitoring and a dedicated 1.25 V comparator for power-fail detection on the PFI input. Its reset generator guarantees valid logic-level outputs even as VCC drops to 1 V, enabling fail-safe shutdown sequencing.

No watchdog timer is integrated - unlike the ADM706R series - freeing design resources while retaining MR-triggered reset, PFO-driven early-warning interrupts, and independent reset assertion timing controlled by an internal 200 ms monostable.

Key Specifications

Pinout & Package

ADM708RAN is housed in an 8-lead narrow-body plastic dual in-line package (PDIP, N-8), compliant with JEDEC MS-001, with 0.300-inch body width and 0.100-inch lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX708RCSA+, ADM708RAN offers lower quiescent current and documented PFI hysteresis implementation; compared with TPS3808G12DBVR, ADM708RAN delivers native dual-reset capability without added components, simplifying layout in space-constrained industrial PCBs.

Availability

ADM708RAN is available at Aetrix Electronics and suitable for industrial controller monitoring, portable medical instrumentation, smart sensor node deployment, and embedded test equipment requiring stable component supply across extended temperature ranges.

Supply support for ADM708RAN 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 ADM708RAN belongs to the ADM706/ADM708 family of microprocessor supervisory circuits designed specifically for robust, low-power, dual-output reset generation in 3 V/3.3 V embedded systems with stringent reliability requirements.

FAQ

What is the reset threshold voltage of the ADM708RAN?

The ADM708RAN has a precision reset threshold of 2.63 V, with ±70 mV tolerance over temperature and supply. This value is factory-trimmed and specified in Table 1 of the Rev. E datasheet. The threshold ensures reliable detection of 3 V supply brownout conditions while avoiding false triggers near nominal operation. The ADM708RAN maintains this exact threshold regardless of VCC within its 1.0 V to 5.5 V operating range, and it is distinct from the 2.93 V (ADM708S) and 3.08 V (ADM708T) variants.

Does the ADM708RAN include a watchdog timer function?

No, the ADM708RAN does not include a watchdog timer. Unlike the ADM706R series, the ADM708RAN omits the WDI and WDO pins entirely - Pin 6 is designated NC (No Connect), and the functional block diagram shows no watchdog circuitry. Its supervision is limited to VCC monitoring, manual reset (MR), and power-fail detection (PFI/PFO). If watchdog functionality is required, the ADM706RAN is the functionally matched counterpart with identical reset threshold and packaging.

How do the two RESET outputs on the ADM708RAN differ in behavior?

The ADM708RAN provides two independent, complementary reset outputs: Pin 7 (RESET) is active-low, and Pin 8 (RESET) is active-high. Both assert simultaneously for exactly 200 ms upon VCC drop below 2.63 V or MR assertion, and both deassert together after the timeout. They share identical drive strength (500 µA sink/source at 3.3 V) and timing - neither is delayed or inverted relative to the other. This dual-output architecture eliminates external inverters in systems requiring both logic polarities, such as interfacing with legacy peripherals and modern SoCs.

Can the ADM708RAN operate reliably when VCC falls below 1 V?

The ADM708RAN guarantees valid RESET output states down to VCC = 1 V, as explicitly stated in the General Description and validated in Figure 12 of the datasheet. Below 1 V, the internal output transistors lose drive capability, and RESET may float or rise weakly. For applications requiring forced low-state below 1 V, Analog Devices recommends adding an external 10 kΩ pull-down resistor from RESET to GND, as shown in Figure 19. This ensures deterministic behavior during deep discharge or catastrophic supply collapse.

What package options are available for the ADM708RAN?

ADM708RAN is exclusively offered in the 8-lead narrow-body plastic dual in-line package (PDIP, N-8), per the Ordering Guide on page 14 of Rev. E. It is not available in SOIC (R-8) or tape-and-reel variants under the "AN" suffix - those use the "AR" or "ARZ" suffixes (e.g., ADM708RARZ). The N-8 package measures 0.300 inches wide with 0.100-inch lead pitch and complies with JEDEC MS-001 standards, making it suitable for through-hole prototyping and legacy industrial assembly.