Analog Devices Inc. ADM8694ARN

Overview

ADM8694ARN from Analog Devices is a microprocessor supervisory circuit providing power-on/brownout reset, battery backup switchover, watchdog timer, and power-fail detection in a 16-lead TSSOP package. It asserts RESET down to VCC = 1 V, delivers up to 100 mA at VOUT, features 4.65 V reset threshold with 40 mV hysteresis, and supports 100 ms or 1.6 s watchdog timeout. It is used in industrial controllers and embedded systems requiring reliable power monitoring and nonvolatile memory protection.

For engineers reviewing the ADM8694ARN datasheet, ADM8694ARN pinout, ADM8694ARN application, or ADM8694ARN equivalent, key selection considerations include its 16-pin TSSOP footprint, dual-mode watchdog (fixed/adjustable), battery switchover with 70 mV rise/50 mV fall thresholds, CE gating capability, and compatibility with 5 V ±5% supplies in automotive and industrial environments.

Technical Context

The ADM8694ARN implements a precision voltage monitor with 4.65 V reset threshold and 40 mV hysteresis, ensuring stable reset assertion during brownout conditions. Its internal PMOS switch provides 0.7 Ω on-resistance for main supply path and 7 Ω for battery path, enabling 100 mA VOUT drive and sub-1 V operation.

It integrates a three-level WDI input with 5 MΩ impedance and 38% VCC bias, supporting watchdog timeout selection via OSC SEL/OSC IN pins. The device includes dedicated PFO (power-fail output), BATT ON, LOW LINE, and active-high RESET outputs - all confirmed in the ADM8691/ADM8695 functional block diagram and pin table.

Key Specifications

Pinout & Package

ADM8694ARN is housed in a 16-lead TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), identical to the ADM8691/ADM8695 family members per Analog Devices Rev. C datasheet Figure 4 and Ordering Guide.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX691ACPE+ and TPS3823DBVR, ADM8694ARN uniquely integrates battery switchover, CE gating, dual watchdog modes, and power-fail warning in one 16-lead TSSOP - reducing BOM count and PCB area while enabling robust data retention in mission-critical embedded systems.

Availability

ADM8694ARN is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply, long-term lifecycle support, and qualified sourcing for safety-critical designs.

Supply support for ADM8694ARN 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 since 1965.

The ADM869x family was designed specifically for microprocessor system supervision - integrating reset, watchdog, battery switchover, and memory protection into single-chip solutions for reliability-critical embedded applications.

FAQ

What is the function of the OSC SEL pin on the ADM8694ARN?

The OSC SEL pin on the ADM8694ARN selects the oscillator source for reset timing and watchdog timeout. When high or floating, it enables the internal oscillator and allows OSC IN to choose between 100 ms or 1.6 s watchdog periods. When low, it enables external clock or capacitor-based timing. This configuration flexibility is confirmed in Table 5 and Figures 17–20 of the Rev. C datasheet.

Does the ADM8694ARN support active-high and active-low reset outputs simultaneously?

Yes, the ADM8694ARN provides both active-low RESET (Pin 15) and active-high RESET (Pin 16) outputs. These are complementary signals derived from the same internal reset generator, allowing direct interface with microprocessors requiring either polarity without external inverters - a feature explicitly documented in the Pin Function Descriptions (Page 7) and General Description (Page 3).

Can the ADM8694ARN drive CMOS RAM directly without external transistors?

Yes, the ADM8694ARN can drive CMOS RAM directly via its VOUT pin, which delivers up to 100 mA with ≤0.2 V dropout at full load. Its internal PMOS switch has 0.7 Ω on-resistance in normal mode, eliminating the need for external pass transistors in most RAM backup applications - as verified in the Battery Switchover Section (Page 11) and Specifications Table 2 (Page 4).

What is the minimum VCC voltage at which ADM8694ARN guarantees RESET assertion?

The ADM8694ARN guarantees RESET assertion down to VCC = 1 V, as stated in the Product Highlights (Page 1), General Description (Page 3), and RESET Output Voltage specification (Table 2, Page 4). This ensures the microprocessor remains held in reset during deep brownout conditions, preventing undefined operation.

How does the ADM8694ARN handle battery switchover hysteresis?

The ADM8694ARN uses asymmetric hysteresis: switchover occurs at +70 mV (VCC rising above VBATT) and −50 mV (VCC falling below VBATT), yielding 20 mV total hysteresis. This prevents oscillation during slow VCC transitions and is explicitly defined in the Battery Switchover Section (Page 11) and Table 2 (Page 4) of the datasheet.