Analog Devices Inc. ADM823LYRJ-R7

Overview

ADM823LYRJ-R7 from Analog Devices is a precision supervisory circuit with integrated watchdog timer and manual reset input, designed for microprocessor supply voltage monitoring in automotive-grade systems. It features a 4.63 V reset threshold, 140 ms minimum reset timeout, 1.6 sec watchdog timeout, push-pull active-low RESET output, and operates across −40°C to +125°C.

For engineers reviewing the ADM823LYRJ-R7 datasheet, ADM823LYRJ-R7 pinout, ADM823LYRJ-R7 application, or ADM823LYRJ-R7 equivalent, this device supports robust power-on/power-down sequencing, brownout recovery, and code-execution integrity verification in safety-critical embedded controllers.

Technical Context

The ADM823LYRJ-R7 implements a precision bandgap-based reset comparator with 40 ppm/°C temperature coefficient and 10 mV hysteresis, ensuring stable threshold behavior over automotive temperature extremes. Its watchdog timer clears on any logic transition at WDI (min. 50 ns pulse width) and asserts reset if unattended for ≥1.12 sec.

Manual reset is supported via an internal 52 kΩ pull-up on MR, requiring only a 1 µs low pulse to trigger reset with 500 ns propagation delay. The push-pull RESET output remains valid down to VCC = 1 V and sinks 3.2 mA at VTH min, enabling direct interface with TTL/CMOS inputs without external pull-ups.

Key Specifications

Pinout & Package

ADM823LYRJ-R7 is housed in a 5-lead SOT-23 package (JEDEC MO-178-AA, RJ-5), 2.90 mm × 1.60 mm × 1.15 mm, with gull-wing leads and 0.95 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM823LYRJ-R7, MAX6326UT46D3+T omits critical fault-recovery features (watchdog, MR), while TPS3808G33DBVR targets different voltage domains and lacks automotive qualification - ADM823LYRJ-R7 remains optimal for 5 V automotive microcontroller supervision requiring full feature set in SOT-23.

Availability

ADM823LYRJ-R7 is available at Aetrix Electronics and suitable for automotive engine control, ADAS camera modules, and industrial PLC I/O requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM823LYRJ-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 leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM823 family delivers automotive-qualified power supervision with integrated watchdog and manual reset - engineered specifically for reliability-critical microprocessor systems in harsh environments.

FAQ

What is the exact reset threshold voltage of ADM823LYRJ-R7 and how does it vary with temperature?

The ADM823LYRJ-R7 has a nominal reset threshold of 4.63 V at 25°C, with guaranteed range of 4.50 V to 4.75 V across −40°C to +125°C. Its temperature coefficient is 40 ppm/°C, resulting in ≤±12 mV drift over the full automotive range - sufficient for stable 5 V rail supervision without calibration.

Does ADM823LYRJ-R7 support operation below 1.8 V supply voltage?

Yes, ADM823LYRJ-R7 guarantees functional reset output down to VCC = 1 V, with specified supply current of 5 µA at VCC = 4.75–5.5 V and valid operation confirmed from 1.2 V to 5.5 V. This enables use in brownout scenarios where main rail sags but remains above 1 V.

Can ADM823LYRJ-R7 be used as a direct replacement for ADM823LYKSZ-R7?

No - ADM823LYRJ-R7 uses a 5-lead SOT-23 (RJ-5) package, while ADM823LYKSZ-R7 uses 5-lead SC70 (KS-5). Though electrically identical, their footprints differ: SOT-23 measures 2.90 mm × 1.60 mm, SC70 is 2.00 mm × 1.25 mm. PCB redesign is required for substitution.

What is the minimum pulse width required on the MR pin to assert reset in ADM823LYRJ-R7?

The MR pin of ADM823LYRJ-R7 requires a minimum low pulse width of 1 µs to reliably trigger reset, with typical propagation delay of 500 ns from MR deassertion to RESET deassertion. On-chip debounce rejects glitches <100 ns, ensuring noise immunity in electrically noisy automotive environments.

How does the watchdog timer in ADM823LYRJ-R7 interact with power supply faults?

When VCC drops below 4.63 V, ADM823LYRJ-R7 asserts RESET regardless of WDI state - and simultaneously clears the watchdog timer. The timer only resumes counting after VCC rises above threshold and RESET deasserts, preventing false timeouts during brownout recovery sequences.