Analog Devices Inc. ADM707AR

Overview

ADM707AR from Analog Devices is a low-cost microprocessor supervisory circuit designed for 5 V supply monitoring in embedded systems. It provides active-high and active-low reset outputs, a 4.65 V precision voltage monitor, 200 ms reset pulse width, and power-fail detection via PFI/PFO. It operates down to 1 V VCC and draws only 190 μA quiescent current - ideal for industrial controllers requiring reliable power-on reset and brownout protection.

For engineers reviewing the ADM707AR datasheet, ADM707AR pinout, ADM707AR application, or ADM707AR equivalent, key selection criteria include its dual-reset output polarity, guaranteed reset validity below 1 V, absence of watchdog timer (distinguishing it from ADM705/ADM706), and compatibility with TTL/CMOS manual reset inputs in space-constrained SOIC-8 layouts.

Technical Context

The ADM707AR implements a precision bandgap-based voltage reference (4.65 V ±150 mV) to trigger reset assertion during power-up, brownout, or power-down. Its internal reset generator holds RESET low for 200 ms after VCC exceeds threshold or MR deasserts, ensuring stable microprocessor initialization.

It integrates a dedicated 1.25 V power-fail comparator with nanosecond-scale response (Fig. 8–9), enabling early warning of supply collapse via PFI/PFO. Unlike ADM705/ADM706, it omits watchdog circuitry - simplifying design where software activity monitoring is handled externally or unnecessary.

Key Specifications

Pinout & Package

ADM707AR 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 size. Thermal impedance θ_JA = 110°C/W supports operation up to +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM707AR, ADM707ARZ offers identical functionality with RoHS compliance, while MAX707CPA+ sacrifices active-high reset capability and consumes more current - making ADM707AR optimal for new designs needing dual-output flexibility and low power.

Availability

ADM707AR is available at Aetrix Electronics and suitable for industrial PLC control, medical diagnostic equipment, automotive body control modules, and networked industrial sensor hubs requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for ADM707AR 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–ADM708 family was engineered for cost-sensitive microprocessor supervision in industrial and computing systems - delivering robust power monitoring, reset generation, and power-fail warning in compact SOIC and PDIP packages.

FAQ

What is the reset threshold voltage for ADM707AR?

The ADM707AR features a precision 4.65 V reset threshold with ±150 mV tolerance over temperature. This value is fixed and factory-trimmed - not adjustable - and ensures reset assertion before the 5 V supply falls below the minimum operating voltage of most microcontrollers. The ADM707AR maintains this specification across its full industrial temperature range (−40°C to +85°C) and guarantees valid reset output down to VCC = 1.0 V.

Does ADM707AR include a watchdog timer function?

No, the ADM707AR does not include a watchdog timer. It belongs to the ADM707/ADM708 subgroup, which omits the WDI/WDO pins and associated timing circuitry present in ADM705/ADM706. Instead, ADM707AR provides dual-reset outputs (active-high and active-low) and a dedicated power-fail comparator (PFI/PFO). If watchdog functionality is required, ADM705AR or ADM706AR must be selected.

What is the purpose of the NC pin on ADM707AR?

Pin 6 on the ADM707AR is marked NC (No Connect) and is internally unbonded. Per the official Analog Devices datasheet (Figure 4 and Table 3), this pin must remain unconnected in PCB layout - no trace, pad, or solder should be attached. Connecting it may cause unpredictable behavior or damage. The NC designation reflects the device's functional differentiation from the ADM705/ADM706 variants, which use this pin for WDI input.

Can ADM707AR drive a microprocessor reset pin directly without external components?

Yes, ADM707AR can drive most microprocessor reset pins directly. Its active-low RESET (pin 7) sinks up to 3.2 mA at 0.4 V, and active-high RESET (pin 8) sources up to 800 μA at VCC − 1.5 V - compatible with standard CMOS/TTL input thresholds. No external pull-up or pull-down resistors are needed unless interfacing with open-drain systems or bidirectional reset lines, where a 4.7 kΩ current-limiting resistor is recommended per datasheet Figure 21.

How does the power-fail comparator in ADM707AR work?

The ADM707AR's power-fail comparator uses an internal 1.25 V reference connected to the inverting input; the noninverting input is exposed as the PFI pin. When voltage at PFI drops below 1.25 V - typically set via a resistive divider from a monitored supply - the PFO output goes low. This provides nanosecond-scale response (Fig. 8–9) for early warning of supply collapse. PFO is open-drain and requires an external pull-up resistor to generate a logic-high signal when inactive.