Analog Devices Inc. ADM709RANZ

Overview

ADM709RAN from Analog Devices is a precision power supply monitor IC with active-low reset output, 2.63 V threshold, 140 ms minimum power-on reset pulse, and operation down to 1 V supply voltage; used for reliable microprocessor reset in industrial embedded systems requiring brownout and power-up supervision.

For engineers reviewing the ADM709RAN datasheet, ADM709RAN pinout, ADM709RAN application, or ADM709RAN equivalent, key selection factors include reset threshold accuracy (±0.08 V), guaranteed RESET functionality at VCC ≥ 1 V, 35 µA quiescent current at low VCC, and compatibility with bidirectional µP reset lines via external series resistor.

Technical Context

The ADM709RAN implements a comparator-based reset generator with internal timing circuitry that holds RESET low for ≥140 ms after VCC rises above 2.63 V, and asserts RESET immediately when VCC falls below 2.55 V (min). It features glitch immunity against short VCC transients and maintains valid RESET output down to 1 V VCC.

Its architecture includes no internal pull-up on RESET - the output is open-drain compatible with external pull-up, supports sink currents up to 1.2 mA at 0.3 V, and requires no external components for basic operation beyond optional VCC decoupling capacitor (≥0.1 µF) and pull-down resistor (100 kΩ) if RESET must remain asserted below 1 V.

Key Specifications

Pinout & Package

ADM709RAN is housed in an 8-pin plastic DIP (N-8) package with 0.3 inch body width and through-hole mounting. Pin 1 is marked by notch or dot; pins 1, 4, 5, 6, and 8 are internally unconnected (NC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply monitor applications.

Compared with MAX709RCPA+ and TPS3808G12DBVR, the ADM709RAN uniquely combines guaranteed 1 V operation, tight 2.63 V threshold tolerance, DIP packaging, and documented glitch immunity - making it optimal for industrial and automotive designs where robustness and ease of prototyping are critical.

Availability

ADM709RAN is available at Aetrix Electronics and suitable for industrial PLC controllers, medical handheld diagnostics, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM709RAN 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The ADM709 belongs to Analog Devices' precision power monitoring product line, designed specifically for deterministic microprocessor reset generation in harsh industrial and automotive environments where reliability under voltage transients is non-negotiable.

FAQ

What is the exact reset threshold voltage for ADM709RAN?

The ADM709RAN has a nominal reset threshold of 2.63 V, with a guaranteed range of 2.55 V (min) to 2.70 V (max) over the full –40°C to +85°C temperature range. This value is laser-trimmed at wafer test and does not require external calibration. The ADM709RAN's threshold is optimized for supervision of +2.8 V and +3.0 V logic supplies, and its tight tolerance ensures consistent reset behavior across production units and temperature extremes.

Does ADM709RAN support operation below 2.0 V VCC?

Yes, the ADM709RAN guarantees functional RESET output down to 1.0 V VCC - a key differentiator versus most competing supervisors. At VCC = 1.0 V, RESET remains low and can sink 50 µA while maintaining ≤0.3 V output voltage. For applications requiring RESET to stay asserted *below* 1.0 V, a 100 kΩ pull-down resistor between RESET and GND is recommended per Analog Devices' Figure 5.

Is ADM709RAN pin-compatible with MAX709R?

Yes, ADM709RAN is a direct pin-compatible upgrade for MAX709R in 8-pin DIP (N-8) packages. Both share identical pinout: VCC (Pin 2), GND (Pin 3), RESET (Pin 7), and NC on Pins 1,4,5,6,8. The ADM709RAN improves upon MAX709R with tighter threshold tolerance (±0.08 V vs. ±0.15 V), lower quiescent current (35 µA vs. 50 µA), and guaranteed 1 V operation - no PCB changes required.

What is the minimum power-on reset pulse width for ADM709RAN?

The ADM709RAN guarantees a minimum RESET active time of 140 ms after VCC rises above the 2.63 V threshold. Typical duration is 280 ms, and maximum is 380 ms under worst-case conditions. This fixed timeout is generated by an internal RC timer and does not depend on external components - ensuring predictable boot sequencing across all operating conditions and temperatures.

Can ADM709RAN interface directly with a bidirectional microcontroller reset line?

Yes, ADM709RAN can interface with bidirectional µP reset lines (e.g., MC68HC11) using a 4.7 kΩ series resistor between RESET (Pin 7) and the microcontroller pin, as shown in Analog Devices' Figure 6. This prevents signal contention during µP-driven reset assertion while allowing the ADM709RAN to drive the line low during power faults. No additional buffering or level translation is needed.