Analog Devices Inc. ADM823RYRJ-R7

Overview

ADM823RYRJ-R7 from Analog Devices is a supervisory circuit with integrated watchdog timer and manual reset input, designed for microprocessor supply voltage monitoring and code execution integrity assurance. It features a 2.63 V reset threshold (±50 mV), 140 ms minimum reset timeout, 1.6 sec typical watchdog timeout, push-pull active-low RESET output, and operates across −40°C to +125°C in automotive-grade SOT-23 packaging. It is used in engine control units to prevent lockup during voltage brownouts.

For engineers reviewing the ADM823RYRJ-R7 datasheet, ADM823RYRJ-R7 pinout, ADM823RYRJ-R7 application, or ADM823RYRJ-R7 equivalent, key selection criteria include reset threshold accuracy, guaranteed reset validity down to VCC = 1 V, manual reset pulse width tolerance (≥1 µs), watchdog input transition sensitivity (50 ns min), and SC70/SOT-23 package compatibility with space-constrained PCB layouts.

Technical Context

The ADM823RYRJ-R7 implements a precision bandgap-based voltage reference with 40 ppm/°C temperature coefficient and 5 mV hysteresis to ensure stable reset assertion across automotive temperature extremes. Its internal watchdog timer clears on any logic transition at WDI and asserts reset if no transition occurs within 1.12–2.40 sec.

Reset generation combines three independent triggers: VCC falling below 2.63 V (with 50 mV hysteresis), MR pin pulled low ≥1 µs, or WDI inactivity exceeding watchdog timeout. The push-pull RESET output guarantees logic-low state down to VCC = 1 V with 3.2 mA sink capability at VTH min.

Key Specifications

Pinout & Package

ADM823RYRJ-R7 is housed in a 5-lead SOT-23 (RJ-5) package per JEDEC MO-178-AA, with 0.95 mm lead pitch and 2.90 mm × 1.60 mm body size. Thermal resistance θJA is 270°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UT26D3+T and TPS3808G12QDBVRQ1, ADM823RYRJ-R7 uniquely integrates manual reset, watchdog timer, and push-pull output in a single SOT-23 package - eliminating external components and enabling both power-fail and software-fail recovery in safety-critical automotive nodes.

Availability

ADM823RYRJ-R7 is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, industrial PLC I/O modules, telematics control units, and automotive body electronics requiring stable component supply across extended temperature ranges.

Supply support for ADM823RYRJ-R7 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, Inc. is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM823 family is part of Analog Devices' supervisory IC product line, engineered specifically for automotive and industrial systems demanding robust power monitoring, watchdog-based firmware supervision, and manual reset capability in minimal footprint packages.

FAQ

What is the exact reset threshold voltage of ADM823RYRJ-R7 and its tolerance over temperature?

The ADM823RYRJ-R7 has a nominal reset threshold of 2.63 V at 25°C, with a guaranteed range of 2.55 V to 2.70 V across the full −40°C to +125°C operating temperature range. This 50 mV total variation includes 40 ppm/°C temperature coefficient and 5 mV hysteresis, ensuring predictable brownout response in automotive environments where supply rails fluctuate under load.

Does ADM823RYRJ-R7 require external components to function as a complete reset supervisor?

No, ADM823RYRJ-R7 operates autonomously with no external components required. Its internal 52 kΩ MR pull-up resistor eliminates the need for an external pull-up, and the push-pull RESET output drives standard CMOS inputs directly. Only bypass capacitance on VCC (recommended 0.1 µF) is advised for enhanced power supply noise immunity - no RC timing networks or additional resistors are necessary for basic operation.

How does the watchdog timer in ADM823RYRJ-R7 interact with power supply faults?

When a VCC undervoltage event occurs, the ADM823RYRJ-R7 asserts RESET and simultaneously clears the watchdog timer. The timer remains disabled until RESET deasserts after VCC rises above threshold and the 140 ms timeout expires. This prevents spurious watchdog timeouts during power-up or brownout recovery, ensuring the watchdog only monitors firmware execution during stable power conditions.

Can ADM823RYRJ-R7 be used in systems with VCC below 2.63 V, such as 1.8 V or 2.5 V logic domains?

Yes, ADM823RYRJ-R7 functions correctly with VCC as low as 1 V, and its RESET output remains valid down to that level. However, the 2.63 V reset threshold means it will assert RESET continuously when VCC is below 2.55 V (minimum threshold). For supervision of sub-2.63 V rails, select a variant like ADM823SYRJ-R7 (2.93 V) or ADM823TYRJ-R7 (3.08 V) - the RY suffix specifically denotes the 2.63 V threshold option.

What is the minimum pulse width required on the MR pin to guarantee reset assertion in ADM823RYRJ-R7?

The ADM823RYRJ-R7 requires a minimum MR low pulse width of 1 µs to guarantee reset assertion, with typical performance showing reliable triggering down to 100 ns across temperature. The internal debounce circuit rejects glitches shorter than 100 ns, ensuring noise immunity while maintaining responsiveness to legitimate manual reset commands from mechanical push-buttons or GPIO-controlled signals.