Analog Devices Inc. ADM705ARZ-REEL7

Overview

ADM705ARZ-REEL7 from Analog Devices is a low-cost microprocessor supervisory circuit designed for 5 V supply monitoring in embedded systems. It provides guaranteed active-low RESET output down to VCC = 1 V, 4.65 V precision reset threshold, 200 ms reset pulse width, and integrated watchdog timer with 1.60 sec timeout - enabling reliable power-up, brownout, and software stall detection in industrial controllers and intelligent instruments.

For engineers reviewing the ADM705ARZ-REEL7 datasheet, ADM705ARZ-REEL7 pinout, ADM705ARZ-REEL7 application, or ADM705ARZ-REEL7 equivalent, key selection criteria include reset threshold accuracy (4.65 V), guaranteed operation below 1 V VCC, manual reset debouncing, PFI/PFO power-fail warning capability, and SOIC-8 packaging compatibility with standard PCB layouts.

Technical Context

The ADM705ARZ-REEL7 implements a precision voltage monitor with 40 mV hysteresis and internal 1.25 V reference for PFI comparator functionality. Its watchdog circuit responds to WDI transitions (high-to-low or low-to-high) and resets on each toggle, with timeout enforced at 1.60 sec ±0.60 sec.

RESET assertion is triggered by VCC falling below 4.65 V or MR pulled below 0.8 V, and remains asserted for ≥160 ms after recovery. The device supports bidirectional reset line interfacing via external current-limiting resistor and guarantees valid logic levels across full 1 V–5.5 V VCC range.

Key Specifications

Pinout & Package

ADM705ARZ-REEL7 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 × 4.00 mm body, and gull-wing leads. Thermal impedance θJA = 110°C/W enables operation up to +85°C ambient without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX705CSA+ and TPS3808G33DBVR, ADM705ARZ-REEL7 uniquely integrates watchdog timer, PFI/PFO comparator, and 1 V valid reset in a single SOIC-8 package - making it the only option among the three that satisfies full 5 V supervisory requirements including software stall detection and auxiliary supply monitoring.

Availability

ADM705ARZ-REEL7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, telecom remote terminal units, and automotive body control modules requiring stable component supply and long-term lifecycle support.

Supply support for ADM705ARZ-REEL7 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, headquartered in Norwood, MA, with design and manufacturing operations worldwide.

The ADM705/ADM706 family was engineered specifically for cost-sensitive, space-constrained microprocessor systems needing robust power supervision, watchdog monitoring, and power-fail warning - targeting industrial, computing, and instrumentation markets.

FAQ

What is the reset threshold voltage of the ADM705ARZ-REEL7?

The ADM705ARZ-REEL7 has a precision reset threshold of 4.65 V with ±0.15 V tolerance over temperature. This value is factory-trimmed and specified in Table 1 of the Rev. H datasheet. The threshold applies to both power-up and brownout detection, and the device guarantees RESET remains asserted until VCC rises above this level plus 40 mV hysteresis. The ADM705ARZ-REEL7 does not support adjustable or user-programmable thresholds.

Does the ADM705ARZ-REEL7 include a watchdog timer?

Yes, the ADM705ARZ-REEL7 includes an independent watchdog timer with a nominal timeout period of 1.60 seconds. The timer is cleared on any transition (high-to-low or low-to-high) at the WDI pin and asserts WDO low if no transition occurs within the timeout window. The watchdog is disabled when WDI is left floating or connected to a high-impedance source. This feature is confirmed in the Functional Block Diagram (Figure 1) and Specifications table of the ADM705/ADM706/ADM707/ADM708 datasheet.

Can the ADM705ARZ-REEL7 monitor a secondary power supply?

Yes, the ADM705ARZ-REEL7 can monitor a secondary supply using its PFI (Power Fail Input) and PFO (Power Fail Output) pins. The internal 1.25 V reference compares against the voltage applied to PFI via an external resistor divider. When PFI falls below 1.25 V, PFO goes low - enabling early warning of supply collapse or battery depletion. This capability is documented in the "Power Fail Comparator" section and Figure 15 of the datasheet.

What package type is used for the ADM705ARZ-REEL7?

The ADM705ARZ-REEL7 uses an 8-lead Standard Small Outline Package (SOIC_N), also designated R-8 per JEDEC MS-012-AA. It measures 5.00 mm × 4.00 mm with 1.27 mm lead pitch and gull-wing leads. The "-REEL7" suffix indicates tape-and-reel packaging with 1,000 units per reel, and "Z" denotes RoHS-compliant construction. This package is confirmed in the Ordering Guide on page 12 of the Rev. H datasheet.

Is the ADM705ARZ-REEL7 compatible with 3.3 V microcontrollers?

The ADM705ARZ-REEL7 is designed for 5 V systems and requires VCC between 4.75 V and 5.5 V for full specification compliance, though RESET remains valid down to VCC = 1 V. Its logic thresholds (e.g., MR low = 0.8 V, WDI high = 3.5 V) are TTL/CMOS-compatible but not optimized for direct 3.3 V interface without level translation. For 3.3 V applications, Analog Devices recommends the ADM707/ADM708 variants or dedicated 3.3 V supervisors like the ADM6315 series.