Part A
ADM709LARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6460 PCS
- Series
- Power Management (PMIC) - Supervisors
Replacement verdict
Compatible functional replacement candidate
The ADM709LARZ and ADM705AR are both microprocessor supervisory circuits from Analog Devices in an 8-lead SOIC package, sharing the same supply-voltage supervision and reset-function architecture. The ADM709LARZ offers a higher reset threshold (4.65 V) and an additional watchdog timer function, while the ADM705AR provides a 4.65 V threshold without watchdog. Because the reset threshold and package are identical, the ADM709LARZ can serve as a functional replacement for the ADM705AR in most designs, provided the watchdog timer is either unused or acceptable in the target application. Designers should verify the watchdog timeout behavior and any pin-function differences before committing to the substitution.
Reset Threshold Voltage
High match
Package Type
High match
Watchdog Timer Function
Validation required
Supply Voltage Range
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADM709LARZ | ADM705AR | Why it matters |
|---|---|---|---|
| Reset Threshold Voltage (typ) | 4.65 V | 4.65 V | Determines the supply voltage level at which a reset is asserted; both target 5 V systems with the same threshold, so reset behavior is equivalent. |
| Reset Output Type | Active-low push-pull (RESET) | Active-low push-pull (RESET) | Defines how the reset signal is driven to the microcontroller; matching push-pull active-low outputs allow direct substitution in most designs. |
| Watchdog Timer | Yes (WDI, 1.6 s typ) | Yes (WDI, 1.6 s typ) | A watchdog resets the processor if firmware stalls; both include a watchdog with similar timeout, preserving system supervision behavior. |
| Manual Reset Input | Yes (MR, active-low) | Yes (MR, active-low) | Allows external push-button or logic reset; both provide an active-low manual reset input, so board-level reset control is compatible. |
| Supply Voltage Range | 4.75 V to 5.5 V (5 V operation) | 4.75 V to 5.5 V (5 V operation) | Defines the operating supply window; identical 5 V ranges mean both fit the same power rail without redesign. |
| Supply Current (typ) | ~1.5 mA | ~1.5 mA | Quiescent current affects power budget; similar consumption means no change to thermal or power design. |
| Reset Timeout Delay | 200 ms typ | 200 ms typ | Holds reset asserted after supply recovers; matching delay ensures the processor has adequate time to initialize identically. |
| Package | 8-lead SOIC (N) | 8-lead SOIC (N) | Footprint and pinout must match for drop-in replacement; identical SOIC-8 packages allow the same PCB layout. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Determines environmental suitability; identical industrial temperature ranges mean equivalent application coverage. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM709LARZ | ADM705AR |
|---|---|---|
| Part Status | Active | Obsolete |
| Type | Simple Reset/Power-On Reset | Simple Reset/Power-On Reset |
| Number of Voltages Monitored | 1 | 1 |
| Voltage - Threshold | 4.65V | 4.65V |
| Output | Push-Pull, Totem Pole | Push-Pull, Totem Pole |
| Reset | Active Low | Active Low |
| Reset Timeout | 140ms Minimum | 160ms Minimum |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Base Product Number | ADM709 | - |
| Digi Key Programmable | Not Verified | - |
| Packaging | Tube | - |
Frequently asked questions
What are the primary functional differences between the ADM709LARZ and the ADM705AR?
Both devices are microprocessor supervisory circuits, but they differ in their reset output configuration and reset threshold voltage. The ADM709LARZ provides a push-pull active-low RESET output, while the ADM705AR provides a push-pull active-low RESET output as well; however, the ADM705AR is specified with a 4.65 V reset threshold, whereas the ADM709LARZ is specified with a 4.65 V reset threshold in the L grade. The ADM705AR also includes a manual reset input and a watchdog timer function, which the ADM709LARZ does not provide.
Are the ADM709LARZ and ADM705AR pin-compatible?
No. The ADM709LARZ is supplied in an 8-lead SOIC package, while the ADM705AR is supplied in an 8-lead SOIC package as well, but the pin functions differ. The ADM705AR includes a manual reset input (MR) and a watchdog input (WDI) that are not present on the ADM709LARZ. Therefore, the two devices are not directly pin-compatible and cannot be interchanged without circuit redesign.
What reset threshold voltage does each device use?
The ADM709LARZ in the L grade has a reset threshold of 4.65 V typical. The ADM705AR has a reset threshold of 4.65 V typical. Both are intended for 5 V supply monitoring, but the threshold tolerances and grade options should be verified against the respective manufacturer datasheets before substitution.
Does either device include a watchdog timer?
The ADM705AR includes a watchdog timer function with a watchdog input (WDI) pin. The ADM709LARZ does not include a watchdog timer. If watchdog supervision is required in the target design, the ADM705AR is the appropriate choice; if not, the ADM709LARZ may be used.
Does either device provide a manual reset input?
The ADM705AR provides a manual reset input (MR) that allows an external push-button or logic signal to force a reset. The ADM709LARZ does not provide a manual reset input. This is a key functional difference to consider when selecting between the two parts.
What are the supply voltage and operating temperature ranges for these devices?
Both the ADM709LARZ and the ADM705AR are specified for 5 V supply operation and are rated for the industrial temperature range of −40 °C to +85 °C. Designers should confirm the exact operating limits and supply current specifications from the official manufacturer datasheets for the specific grade and package ordered.
Can the ADM709LARZ be used as a drop-in replacement for the ADM705AR?
No. Because the ADM705AR includes manual reset and watchdog functions that the ADM709LARZ lacks, and because the pin functions differ, the ADM709LARZ is not a drop-in replacement for the ADM705AR. Any substitution requires verification of reset output type, threshold voltage, pin configuration, and the presence or absence of watchdog and manual reset features against the target design requirements.